Reducing the risks associated with the ingestion of vegetables grown on soils contaminated with trace metal elements through the application of soil amendments: Results of experiments in Lubumbashi/Democratic Republic of the Congo.

Reducing the risks associated with the ingestion of vegetables grown on soils contaminated with trace metal elements through the application of soil amendments: Results of experiments in Lubumbashi/Democratic Republic of the Congo. | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Reducing the risks associated with the ingestion of vegetables grown on soils contaminated with trace metal elements through the application of soil amendments: Results of experiments in Lubumbashi/Democratic Republic of the Congo. Félicien Mununga Katebe, Gilles Colinet, Jean-Marc Kaumbu Kyalamakasa, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3848977/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 06 Sep, 2024 Read the published version in Environmental Monitoring and Assessment → Version 1 posted 4 You are reading this latest preprint version Abstract The expansion of mining companies in the province of Haut-Katanga in general, and in the city of Lubumbashi in particular, is one of the main causes of the very worrying environmental problems facing the city's inhabitants. These problems include contamination of agricultural and residential soils, river and well water, the atmosphere and vegetables. This study evaluates the effectiveness of organocalcareous soil improvers applied to heavy metal-contaminated soils in reducing the mobility and bioavailability of heavy metals. Trials were conducted under glass at the Faculty of Agronomic Sciences, University of Lubumbashi, using a randomized factorial design with four replications. Treatments included four plant species ( Brassica chinensis, Amaranthus vulgaris, Beta vulgaris and Brassica carinata ), five levels of amendment (D0: no amendment; D1: 150g sawdust; D2: 150g chicken droppings; D3: 75g sawdust and 15g agricultural lime; D4: 75g chicken droppings and 15g agricultural lime), and three types of urban market gardens (Chem-chem; Manoah Kinsevere and Kashamata). The results reveal that the soil and plant biomass of four vegetables are contaminated with metals, with the daily consumption index of vegetables produced on the soils of the Kashamata garden with low copper contamination exceeding the limits authorized by the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) for daily vegetable consumption for a person of 60 kilograms body weight. The daily consumption index was not determined due to insufficient biomass linked to high soil contamination, inhibiting plant growth for the market gardens of Manoah Kinsevere and Chem-Chem, soils moderately and highly contaminated with copper, respectively. However, these vegetables remain unfit for human consumption, underlining the need to adopt new soilless production techniques such as conventional hydroponics or bioponics in areas heavily impacted by anthropogenic activities. Vegetables amendments ingestion risks trace elements Lubumbashi Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction Lubumbashi, a copper-bearing city, is facing environmental problems of great concern to human health, resulting from ore processing activities and the intensification of mining company activities. These activities have resulted in the contamination of soil, water, plants and air. Substantial quantities of metals, including copper (Cu), cobalt (Co), arsenic (As) and cadmium (Cd), exceed the limits set by the World Health Organization (WHO) and are found in agricultural and residential soils (Alfaro et al. 2022 ; He et al. 2020 ; Kinuthia et al. 2020 ; Z. Li et al. 2014 ; Mubemba et al. 2014 ; Shutcha et al. 2015 ; Zhao et al. 2022 ). Contaminated soils transfer metals to plants, interfering with the normal functioning of living organisms (Briffa, Sinagra, and Blundell 2020; Okereafor et al. 2020 ; Zu et al. 2011 ). Studies carried out in Lubumbashi showed that vegetables produced in gardens and sold on various markets were contaminated with heavy metals ranging, for example, from 13.1 to 39.3 mg/kg for copper and 0.33 to 2.94 mg/Kg for cobalt (Al-Hwaiti and Al-Khashman 2015; S. Khan et al. 2010 ; Yang et al. 2011 ). The WHO has proposed toxicity thresholds for copper and cobalt of around 10 and 1 mg/kg vegetable dry matter, respectively (Al-Hwaiti and Al-Khashman 2015; S. Khan et al. 2010 ; Radwan and Salama 2006 ; Yang et al. 2011 ). Heavy metals are extremely harmful to living beings, including humans, plants, other terrestrial and aquatic animals (Ahmed et al. 2023 ; I. U. Khan et al. 2023 ; Kishore, Malik, and Kumari 2023). Due to heavy metal concentrations found in their urine that were above the toxicity threshold (17.8 ppm for As, 0.75 ppm for Cadmium (Cd), 15.7 ppm for Cobalt (Co), 17.1 ppm for Copper (Cu), 3.17 ppm for Lead (Pb), and 0.028 ppm for Uranium (U), human populations living near ore processing and treatment facilities are exposed to contamination by these heavy metals. The toxicity thresholds proposed by the WHO for arsenic, cadmium, cobalt and uranium in urine are 8, 24, 0, 20, 0, 36 and 0.008 mg/kg respectively. (Banza et al. 2009 ; Ilechukwu et al. 2021 ; Kampa and Castanas 2008; Song and Li 2015 ). Similar conclusions were reached by (Bandara et al. 2008 ; Cao et al. 2020 ; Ghayoraneh and Qishlaqi 2017; Gómez-Meda et al. 2017 ; C. Li et al. 2019 ; Munir et al. 2022 ; Pruvot et al. 2006 ; Rai et al. 2019 ; Zeng et al. 2015 ) which showed that consumption of cadmium-contaminated rice had caused kidney failure in 5,000 residents of the agricultural region of Sri Lanka. Faced with such heavy metal contamination, the application of organic or calcareous amendments to metal-contaminated soils is one possible solution for reducing the transfer of metals from soil to plant biomass (C. Li et al. 2019 ; Sarwar et al. 2017 ; Wan, Lei, and Chen 2016; H. M. Chen et al. 2000 ). These amendments aim to reduce the bioavailability and mobility of metals in the soil and in plants. Copper concentrations in the aerial parts of Microchloa altera plants were reduced from (76.3 ± 22.1 mg/kg Cu), to (25.2 ± 3.4 mg/kg) after addition of organic amendments from water hyacinth ( Eichhornia crassipes ) and agricultural lime (Jaskulak, Grobelak, and Vandenbulcke 2020; Lin et al. 2022 ; Mahar et al. 2016 ; Shutcha et al. 2015 ). Studies carried out by (Achiba et al. 2010 ; Mousavi et al. 2018 ; Mubemba et al. 2014 ) showed that the use of organic or limestone amendments to metal-contaminated soils had reduced the mobility of metals in the soil (Cu, Co, Cd, Pb and Zn), but that metal concentrations in vegetables remained above WHO-recommended levels for human consumption of vegetables. (Amin et al., 2023 ; Guo et al., 2020 ; Nkoh et al., 2022 )In China, the application of chicken manure mixed with limestone amendments was shown to increase soil pH and significantly reduce the mobility of metals in the soil and their transfer to maize plants. (Cui et al. 2023 ; W. Liu et al. 2023 ; Vandyck et al. 2023 ) show that the application of limestone amendments to soils contaminated with heavy metals was responsible for increasing soil pH, cation exchange capacity and the stability of metals in soils, thereby reducing the transfer of metals from the soil to the various plants grown on contaminated soils. From these studies (Gao et al. 2023 ; P. Wu et al. 2023 ) report that the effective composting of cow dung and green waste composts applied to metal-contaminated soils reduced the mobility of heavy metals in soils and their bioavailability to lettuce ( Lactuca sativa ) plants. However, most of these studies clearly show that the quantities of both organic and calcareous soil improvers used are very high. The variation in organic matter types and crop types needs to be tested in order to draw the best conclusions applicable to the majority of crops, and to confirm the hypothesis that the use of organic and calcareous soil improvers would reduce the transfer to plants and mobility of metals, especially cobalt and copper, with a view to guaranteeing quality production and nutrition of the vegetables sold and consumed in the city of Lubumbashi. (Franco-Uría et al. 2009 ; S. Khan et al. 2010 ). The aim of this study was to evaluate the effectiveness of different levels of organocalcareous soil improvers in reducing the mobility and bioavailability of trace metals to ensure the quality production of vegetables free from contamination. 2. Materials and methods 2.1. Study site The experiments were carried out between July and September 2019 at the Faculty of Agronomic Sciences, University of Lubumbashi, Democratic Republic of Congo. Lubumbashi's climate is classified CW6 according to the Koppen classification system, characterized by three distinct seasons: a rainy season from November to March, a dry season from May to September, and two transition months (April and October). Average annual rainfall in the region is estimated at around 1,200 mm. Soils in the Lubumbashi region belong to the ferralitic soil category, with a pH of around 5.9, and are mainly colonized by cupricolous plant species such as Cynodon dactylon , Haumaniastrum katangense , Microchloa altera , Imperata cylindrica and Bulbostislis pseudoperenis . The average annual temperature is 20°C (Malaisse 1997 ). The geographical location of this site is specified by the following coordinates: Altitude: 1275 meters, Longitude: 27° 28' 35.7" East, Latitude: 11° 36' 30.6" South. 2.2 Experimental design, soil sampling and crop selection Experimental design : An experiment was carried out to evaluate the effectiveness of organocalcareous amendments on metal mobility and bioavailability, following a completely randomized factorial design, using chicken droppings, sawdust and agricultural lime. For each treatment, soils from both amended and unamended market gardens were placed in polyethylene pots under glass and repeated four times. Soil samples were taken from each of three market gardens in Lubumbashi (Fig. 1 ), and 500 grams of the sampled soils were kept for laboratory analysis to determine the physico-chemical characteristics of the market garden soils. Treatments included four plant species ( Brassica chinensis, Amaranthus vulgaris, Beta vulgaris and Brassica carinata ), five levels of amendment (D0: no amendment; D1: 150g sawdust; D2: 150g chicken droppings; D3: 75g sawdust and 15g agricultural lime; D4: 75g chicken droppings and 15g agricultural lime), as well as three types of urban market gardens (Chem-chem; Manoah Kinsevere and Kashamata). Vegetable crops Of the twenty species most widely grown and consumed in the market gardens of Lubumbashi, four vegetable plants ( Brassica chinensis, Amaranthus vulgaris, Beta vulgaris and Brassica carinata ) were used in these trials. Improved seeds were purchased from local stores in Lubumbashi. After 60 days of cultivation, all plants were harvested and then dried in an oven to determine the heavy metals in the biomass produced, in order to assess the sanitary quality of the vegetables produced after application of the organocalcareous soil improvers alone or mixed with soil from gardens contaminated with heavy metals. Soil : the experiments carried out in 2019 were conducted in polyethylene pots containing 2.5 kg of soil and placed under glass in the experimental garden of the Faculty of Agronomic Sciences at the University of Lubumbashi. Three categories of market garden soils were selected: low copper contamination, medium copper contamination and high copper contamination, respectively Kashamata, Manoah Kinsevere and Chem-Chem (Fig. 2 ). Soils from the market gardens were sampled to a depth of 20 cm, and five soil samples were taken from each garden. The five samples taken from each garden were mixed to form a composite sample, which was then air-dried, crushed in a porcelain mortar and sieved to 2 mm, then preserved and analyzed in the laboratory to determine the physico-chemical characteristics of the garden soils. According to the International Soil Classification, Lubumbashi soils belong to a group of soils known as Ferralsoil group (WRB 2022). Amendments : three types of soil improver were used: chicken droppings, sawdust and dolomitic limestone were applied to soil contaminated with heavy metals. The manure and sawdust were mixed in polyethylene pots, and the agricultural lime was purchased locally. Contaminated soil amendments were applied in polyethylene pots, using locally purchased limestone. The use of limestone amendments to contaminated soils reduces the mobility and bioavailability of metals by increasing soil pH and solubilizing oxides, with the result that trace metals precipitate out. In addition, organic soil improvers, notably chicken droppings and sawdust, were purchased locally in Lubumbashi and composted for 15 days before sowing the crops. Organic amendments are renowned for their richness in organic matter, which positively influences the mobility of trace metal elements in soils by forming organo-metallic complexes, and also raises soil pH levels. 2.3. Measurement and analysis The pH and trace metal content of dried soil samples were determined. Water pH and KCl pH were determined using the potentiometric method (Lasota et al. 2020). Soil samples were ground in a porcelain mortar and sieved using a 2.0 mm mesh sieve. Total metal trace elements in the soil were measured using a portable X-ray fluorescence spectrophotometer (XRF, Olympus Delta Classic Plus, model DCC-4000), as described in (Mpinda et al. 2022 ). Quantities of exchangeable metals in soils were determined using the 0.01 M CaCl 2 extraction method and measured by atomic absorption spectrophotometry (AAS, VARIAN 220, Agilent Technologies, Santa Clara, CA, USA) (Houba, Uittenbogaard, and Pellen 1996 ). Chemical analysis of hen droppings and sawdust was carried out at the Agro-pedological laboratory of the Faculty of Agronomic Sciences, University of Lubumbashi. Samples of hen droppings and sawdust were dried at room temperature for 14 days. Trace metal and major element contents were determined in hen droppings and sawdust to determine the nutritional quality of these amendments. Extraction with aqua regia was carried out using the ISO 11466:1995 method. For extraction, the OCC/RD Congo laboratory used 3 g of sample and 28 ml of aqua regia. After extraction, the extract was filtered through paper filters, diluted with demineralized water, then digested for 20 minutes at 175°C in a microwave digestion vessel. A typical calibration method was used to determine trace metals (Cu, Co, Cd, Pb) in the various materials (chicken droppings, sawdust and agricultural lime) using Perkin Elmer's Optima 7000 DV ICP-OES spectrometer. In order to eliminate soil particles and determine only the metals absorbed by plants, the four vegetables harvested ( B. chinensis , B. carinata , B. vulgaris and A. vulgaris ) were washed with tap water to determine the quantities that consumers were able to ingest. These four vegetable biomasses were oven-dried for 24 hours before being ground to powder in an electric grinder. The quantities of heavy metals in the plants were determined by acid mineralization (HNO + HClO 34 ), and measurements were made using an atomic absorption spectrophotometer of the type (AAS, VARIAN 220, Agilent Technologies, Santa Clara, CA, USA) (Adams and Miller 1998 ). 2.4. Statistical analysis Raw results for vegetative parameters were subjected to a two-factor analysis of variance (ANOVA), and means were compared using a Tukey test with a significance level of 5%. Data processing was carried out using R x64 4.1.2 and Minitab statistical software. 2.5. Physico-chemical characteristics of soils, chicken droppings, sawdust and agricultural lime Three types of urban market gardens (Chem-Chem; Kashamata and Manoah Kinsevere) were selected, and physico-chemical characteristics were determined in each soil of these gardens (Table 1 ). Table 1 Physico-chemical characteristics of soils in Lubumbashi's urban market gardens. Legend. Cu, Cd, Pb and Zn/dispo: available; ˂0.05: below detection limit ; Nd : Not determined Market Gardens/Heavy metals (mg/kg) Kashamata Manoah Kinsevere Chem-Chem Toxicity threshold (mg/kg) pH water 6,7 5,4 5,8 7 pH KCl 6,3 4,5 5 7 TOC (%) 2,54 2,3 3,14 - Cu/total 204 535 1355 100 Cu/dispo 0,026 0,001 0,046 - Cd/total ˂0,05 ˂0,05 45 2 Cd/dispo 0,013 0,002 0,058 - Co/total Nd Nd Nd 30 Co/dispo 0 0,018 0,069 - Pb/total 20 81 221 100 Pb/dispo 1,427 2,472 1,255 - Zn/total 60 394 1470 300 Zn/dispo 0,643 0,261 1,933 - The various organic and calcareous amendments were analyzed to determine their nutritional quality (Table 2 ). The chicken droppings were purchased from an industrial farm located some 15 km from the Faculty of Agronomic Sciences at the University of Lubumbashi. Agricultural lime was purchased from a lime and calcium producer in Likasi, 120 km from Lubumbashi. The sawdust was purchased from the sawmills of the Texaco market, located in the city of Lubumbashi, four kilometers from the Faculty of Agronomic Sciences. Table 2 Physico-chemical characteristics of hen droppings, sawdust and agricultural lime Types of amendment Mg (%) Ca (%) Heavy metals (mg/kg) Cu Co Cd Pb Zn Fe Agricultural quicklime (CaCO 3 . MgCO ) 3 25 52 ˂0,05 ˂0,05 ˂0,05 ˂0,05 ˂0,05 ˂0,05 Hen droppings 0,11 7,48 80,5 5,6 0,04 0,3 321,3 654 Sawdust 0,05 0,12 22,6 2,4 0,3 1,9 21,6 1064 2.6. Estimating the daily intake of vegetables. To determine the level of heavy metal toxicity in plant biomass, the daily dose was estimated for vegetable consumption in the city of Lubumbashi for an individual over a period of one day, one week or even one month. This index also makes it possible to determine the quantities of metals ingested by a person of known body weight, and is calculated using the following relationship [46, 47] : $$\varvec{E}\varvec{D}\varvec{I}=\frac{{\varvec{C}}_{\varvec{m}\varvec{g}/\varvec{k}\varvec{g}}\times \varvec{I}\varvec{n}\varvec{t}\varvec{a}\varvec{k}\varvec{e}\left(\frac{\varvec{k}\varvec{g}}{\varvec{d}\varvec{a}\varvec{y}}\right)}{\varvec{B}\varvec{M}\left(\varvec{k}\varvec{g}\right)}$$ C mg /kg is the average concentration of the metal in the vegetable, where Intake represents the quantity of vegetables to be consumed per day (kg/day), and finally, BM is the average body weight of the vegetable consumer. The WHO recommends eating 300 to 350 grams of vegetables a day. Then, an average of 0.325 kg/person/day was used to estimate the daily dose of vegetables to be consumed, and a body mass of 60 kg was chosen as the average body weight. 3. Results 3.1 Effects of organocalcareous amendments applied to soils contaminated with trace metallic elements on vegetative parameters. 3.1.1. Germination rates of four plants grown on soil contaminated with heavy metals. Figure 3 shows that plant germination rates vary from species to species and from garden to garden. Analysis of variance shows significant differences between the different types of organic material used (p D1 > D0 > D3 > D4 modality. Furthermore, germination rates of B. chinensis plants and analysis of variance show that the use of organocalcareous amendments significantly influenced plant germination at 7 days, with the best germination rate obtained with modality D1 > D0 > D2 > D3 > D4 (p D1 > D3 > D4 > D1, and analysis of variance shows that the application of organocalcareous amendments significantly influenced chard plant germination (p D0 > D2 > D3 > D4, and the analysis of variance shows significant differences between the organocalcareous amendment modalities used (p < 0.05). 3.1.2. Survival rate of A. vulgaris plants grown on soils contaminated with heavy metals. Analysis of variance (ANOVA) revealed that there were significant differences between the market gardens used in terms of plant survival at all observation dates (p˂0.05), unlike the type of amendments applied to the contaminated soils which did not significantly influence amaranth plant survival, however the Kashamata garden had given the highest survival rate unlike the others. Thus, the interaction between market gardens and the type of organic and limestone amendments showed that there were significant differences between treatments in terms of plant survival at all observation dates (p˂0.05), except at day 15 where the ANOVA revealed no significant difference (Fig. 4 ). The survival rate of B. carinata plants ranged from (0.0 + 0.00 to 100.0 + 0.00%), and analysis of variance reveals that there are significant differences (p˂ 0.05) between market gardens in the survival rate of B. carinata plants at all observation dates, with the highest survival rate obtained in the Chem-Chem garden. The application of organic and limestone amendments had a significant influence on B. carinata plant survival (p˂0.05), with the best plant survival rate recorded in the Chem-Chem gardens. On the other hand, the combination of organic and limestone amendments had a significant influence on plant survival (p˂0.05) (Fig. 5 ). The survival rate of B. chinensis plants ranged from 0 to 100%, with Analysis of Variance showing significant differences between market gardens at all observation dates (p˂0.05), except at day 15, where ANOVA showed no significant difference. And the best survival rate of B. chinensis plants was obtained with the Chem-Chem garden. Furthermore, analysis of variance showed that there were significant differences between the types of organic and limestone amendments applied (p˂0.05), for B. chinensis seedling survival at all observation dates except day 15, where ANOVA showed no significant difference. The interaction between vegetable crops and types of organic and limestone amendments significantly influenced (p˂0.05) B. chinensis seedling survival at all observation dates except day 15 th, where ANOVA revealed no significant difference (Fig. 6 ). As for the survival rate of Beta vulgaris plants, analysis of variance shows that the use of different market gardens significantly influenced the survival of B. vulgaris plants at all observation dates (p˂0.05), with the highest survival rate obtained in the Manoah market garden. In all cases, organocalcareous soil amendments significantly influenced the survival rate of B. vulgaris seedlings (p˂0.05) and, the best seedling survival rate was obtained with the modalities (D1 and D0). However, the interaction between market gardens and organocalcareous amendment types significantly influenced B. vulgaris seedling survival at all observation dates, except at day 15 where ANOVA revealed no significant difference (Fig. 7 ). 3.2 Effects of organocalcareous soil improvers on the pH of soils contaminated by heavy metals. Table 3 shows that the application of organocalcareous soil improvers in different market gardens significantly influenced soil pH, irrespective of the plant species grown. ANOVA revealed that the use of three market gardens significantly influenced soil pH. However, the interaction between organocalcareous soil improvers and market gardens also significantly influenced soil pH for all plant species used (p < 0.05). Table 3 Effects of organic amendments on the pH of soils contaminated with heavy metals. Legend: (D0: no amendments; D1: 150 g sawdust; D2: 150 g hen droppings; D3: 75 g sawdust ± 15 g lime; D4: 75 g hen droppings ± 15 g lime; black dot: extreme values; horizontal bar: mean; diamond: median. Gardens Amendments pH A. vulgaris pH B. chinensis pH B. vulgaris pH B. carinata Chemchem D0 5.69 ± 0.03 h 5.69 ± 0.07 fg 6.07 ± 0.10 de 5.96 ± 0.02 de Chemchem D1 5.85 ± 0.02 fgh 6.05 ± 0.06 cd 5.90 ± 0.12 de 6.08 ± 0.09 de Chemchem D2 6.15 ± 0.04 de 6.18 ± 0.09 c 6.14 ± 0.13 c 6.13 ± 0.08 d Chemchem D3 6.37 ± 0.09 cd 6.18 ± 0.14 c 5.85 ± 0.15 ef 6.05 ± 0.06d e Chemchem D4 6.07 ± 0.11 ef 5.82 ± 0.06 ef 6.02 ± 0.08 de 6.46 ± 0.05 c Manoah D0 5.66 ± 0.03 h 5.55 ± 0.11 g 5.60 ± 0.10 ef 5.48 ± 0.10 f Manoah D1 5.83 ± 0.05 gh 5.79 ± 0.07 ef 5.58 ± 0.10 e 5.43 ± 0.07 f Manoah D2 6.33 ± 0.08 d 6.16 ± 0.05 c 5.78 ± 0.06 ef 5.81 ± 0.08 e Manoah D3 6.01 ± 0.06 efg 5.84 ± 0.05 def 5.71 ± 0.06 ef 5.85 ± 0.23 e Manoah D4 6.03 ± 0.07 efg 5.93 ± 0.13 de 5.93 ± 0.13 de 6.05 ± 0.06 de Kashamata D0 6.62 ± 0.12 b 6.97 ± 0.10 ab 6.33 ± 0.10 c 6.69 ± 0.02 bc Kashamata D1 6.77 ± 0.04 b 6.81 ± 0.09 ab 6.47 ± 0.22 c 6.96 ± 0.05 ab Kashamata D2 6.74 ± 0.06 b 6.83 ± 0.05 ab 6.69 ± 0.19 bc 7.11 ± 0.21 a Kashamata D3 6.56 ± 0.07 bc 6.77 ± 0.08 b 6.97 ± 0.08 b 6.76 ± 0.23 b Kashamata D4 7.22 ± 0.22 a 7.02 ± 0.07 a 7.26 ± 0.33 a 7.21 ± 0.18 a Effets sites (p-value) 0.000 0.000 0.000 0.000 Effets matières organiques (p-value) 0.000 0.000 0.000 0.000 Interaction Sites x M.O (p-value) 0.000 0.000 0.000 0.000 Estimated daily consumption of vegetables produced in Lubumbashi's urban market gardens was carried out for the Kashamata market garden, a garden with low copper contamination. In contrast, data from the Chem-Chem and Manoah Kinsevere market gardens are not presented in Table 4 , as the majority of treatments applied did not result in sufficient biomass for analysis of metal concentration. This is due to moderate and high levels of trace metal contamination. In the Kashamata vegetable garden, the daily vegetable consumption indices are below the FAO/WHO limits for daily vegetable consumption per person for most trace metals (Cu, Cd and Pb). Table 4 Determination of daily consumption of leafy vegetables in the city of Lubumbashi (mg/60 Kg/day). Legend: ND: not determined Crop types Gardens Types of amendment Trace metals Cd Cu Pb Co Limit WHO/FAO 0,06 3 0,214 0,055 Amaranthus vulgaris Kashamata D0 0,023 0,375 0,004 0,449 Amaranthus vulgaris Kashamata D1 0,007 0,182 0,005 0,102 Amaranthus vulgaris Kashamata D2 ND ND ND ND Amaranthus vulgaris Kashamata D3 0,002 0,461 0,013 0,056 Amaranthus vulgaris Kashamata D4 0,001 0,805 0,023 0,101 Brassica chinensis Kashamata D0 0,005 0,231 0,004 0,177 Brassica chinensis Kashamata D1 0,004 0,223 0,004 0,05 Brassica chinensis Kashamata D2 0,002 0,208 0,003 0,027 Brassica chinensis Kashamata D3 0,005 0,389 0,003 0,029 Brassica chinensis Kashamata D4 0,002 0,288 0,004 0,05 Brassica carinata Kashamata D0 0,009 0,363 0,004 0,326 Brassica carinata Kashamata D1 0,005 0,385 0,007 0,052 Brassica carinata Kashamata D2 0,002 1,03 0,055 0,119 Brassica carinata Kashamata D3 0,003 0,526 0,029 0,063 Brassica carinata Kashamata D4 0,002 0,947 0,036 0,086 Beta vulgarus Kashamata D0 0,015 0,612 0,012 0,465 Beta vulgarus Kashamata D1 0,007 0,346 0,008 0,084 Beta vulgarus Kashamata D2 ND 0,779 0,029 0,075 Beta vulgarus Kashamata D3 ND ND ND ND Beta vulgarus Kashamata D4 ND ND ND ND However, with regard to cobalt, the results indicate that the four vegetables cannot be consumed by the population of Lubumbashi, as the high quantities of metals found in the leaves exceed the limits set by the FAO/WHO for the daily consumption of vegetables for a person of 60 kg body weight. In addition, the application of organocalcareous amendments influenced the daily consumption index. Treatment D4 proved more effective than other treatments with fewer amendments, following the order of accumulation D4 > D3 > D2 > D1 > D0. 4. Discussion 4.1. Level of soil contamination and/or pollution in market gardens in Lubumbashi. In Lubumbashi, not all soils present the same risks of metal contamination and/or pollution. In view of the levels found in market garden soils, which show that soils located close to mining activities have extremely high levels, often exceeding recommended toxicity thresholds, in contrast to soils where mining is not present (Mubemba et al. 2014 ; Muimba-Kankolongo et al. 2021 ; Mununga Katebe et al. 2023 ). Soil contamination results from a combination of various sources, including natural sources and anthropogenic activities impacting the environment. Agricultural soils in the vicinity of these mineral extraction companies are known to be the most contaminated by trace metals, mainly due to the intensity of their operations (Abiya SE 2019; Muimba-Kankolongo et al. 2021 ; Sonter, Ali, and Watson 2018; Tran et al. 2022 ; Yoon et al. 2023 ) than garden soils away from human activities. Our results corroborate those of (Hu et al. 2013 ) carried out in Canada, which revealed that the mining industry was responsible for heavy metal contamination of river water through the use of land application sludge in agriculture. In addition, mining companies are responsible for the contamination and pollution of agricultural soils (Candeias et al. 2014 ; Giri, Singh, and Mahato 2017; Luo et al. 2022 ; Mirzaei Aminiyan et al. 2018 ; J. Wang et al. 2019 ). This shows that areas close to mining activities have been contaminated by dust, effluent and water containing metal particles. Nevertheless, this contamination has had a disruptive impact on the environment, crops and agricultural soils (He et al. 2020 ; Ma et al. 2015; D. Wang et al. 2020 ). In Lubumbashi, this phenomenon was exacerbated by the liberalization of the Société générale des carrières et mines (GECAMINES), which led to the creation of several mining companies and consequently contaminated the soils of market gardens located near the mining companies. However, different levels of soil contamination and/or pollution may require different remediation techniques. Soils with low or moderate levels of trace metal contamination may require specific approaches such as phytoremediation techniques, but where the level of contamination in market garden soils is higher, it is advisable to switch to other cultivation approaches such as bioponics or hydroponics (Guo et al. 2023 ; Szekely, Zeaiter, and Jijakli 2023). 4.2 Reducing the bioavailability of heavy metals and estimating the daily consumption of vegetables for a high-quality human diet. Organocalcareous soil improvers are proposed as techniques for reducing the transfer of metals from soil to plants. Studies conducted by (Mubemba et al. 2014 ; Shutcha et al. 2015 )have shown that organocalcareous amendments reduce the mobility and bioavailability of trace metals (Frick et al. 2019 ; Khoshru et al. 2023 ; Narayanan and Ma 2023; Sarwar et al. 2017 ; H. Wang et al. 2023 ; Y. J. Wu et al. 2016 ). However, the quantities of amendments are still very large. Our results indicate that the application of organocalcareous amendments reduced the transfer of trace metal elements from the soil to plants, on the one hand by creating chelates of trace metal elements, but on the other hand, they made the soils slightly acidic (Mubemba et al. 2014 ; Shutcha et al. 2015 ). With regard to the daily vegetable consumption index, our results reveal persistent problems, as the consumption indices exceed the limits set by the FAO/WHO for daily vegetable consumption, particularly with regard to cobalt for vegetables from the Kashamata market garden (Abuzed Sadee and Jameel Ali 2023; Adefa and Tefera 2020; Langunu et al. 2023 ; Tasleem et al. 2023 ). This phenomenon could be explained by the fact that the soils of Haut-Katanga province in general, and the city of Lubumbashi in particular, have a pedogeochemical background enriched in copper and cobalt. In addition, the poor management of quarries and mines, as well as the discharge of effluents rich in metallic particles and aerosols containing dust, can contribute to the propensity of this environmental scourge. (Bogaert, Colinet, and Mahy 2018; Shengo et al. 2020 ; Shutcha et al. 2015 ). The recommended quantities of vegetables (300 grams/60kg of an adult) could prove very dangerous for children whose weight is less than that of adults, given the danger that the city of Lubumbashi presents in terms of copper and cobalt production. On the other hand, if we consider the other metallic trace elements (Cu, Pb and Cd), the daily vegetable consumption index indicates that these vegetables can be consumed up to three times a week without exceeding the limits set by the FAO/WHO for daily vegetable consumption for a person of 60 kg body weight (Cherfi et al. 2016 ; Zhuang et al. 2009 ). According to the International Soil Classification, Lubumbashi soils belong to the category of ferralitic soils characterized by the presence of over 20% clay in soil profiles A-C and A-B-C, mainly composed of Kaolinite, as well as iron and aluminum oxides (G. Chen et al. 2019 ). However, the clay component is mainly composed of kaolinite and is mixed with significant amounts of free oxides, resulting in a SiO2/Al2O3 ratio less than or equal to 2. Applying organocalcic soil improvers to ferritic soils contaminated with trace metal elements improves soil fertility and offers a high capacity for immobilizing trace metal elements in the soil. This is due to the high reactivity of dissolved and colloidal iron in ferralsols, mixed with other elements such as Si, Ca, Mg, Na and K introduced by the application of organo-calcium amendments on metal-contaminated soils, destabilizing kaolinite and allowing the formation of 2:1 clay minerals. These minerals then reduce the bioavailability of metals to plants (G. Chen et al. 2019 ; Mohamed, Ahamadou, and Li 2010 ). 4.3 Effect of organocalcareous soil improvers on growth parameters of four vegetable crops grown on soil contaminated with heavy metals in Lubumbashi. The use of organocalcareous amendments aims to increase soil pH and reduce the mobility and bioavailability of metals in agricultural soils (Alam et al. 2020 ; He et al. 2020 ; Tuan et al. 2020 ; Yin et al. 2016 ). However, analysis of variance indicates that the use of various market gardens did not significantly influence amaranth plant emergence rates. This could be attributed to the low nitrogen content of the organic matter supplied to the plants (Felix, Charles, and Wang 2022; Xu et al. 2022 ). Similar conclusions were drawn by (Mubemba et al. 2014 ) who found that the application of organocalcareous amendments to agricultural soils had no significant effect on the growth of A. vulgaris amaranth plants. Furthermore, amaranth plant survival was significantly influenced by market garden types, while organic matter did not significantly influence amaranth plant survival at all observation dates. Similar results were reported by (Ullah et al. 2023 ; M. Wang et al. 2023 ) who found that compost application on metal-contaminated soils did not significantly influence germination and survival of Brassica juncea plants in the Spanish region of Aznalcóllar (Alam et al. 2020 ). Our results can be explained by the fact that during the decomposition of organic matter, specific organic compounds can release substances that have the ability to immobilize heavy metals by forming precipitates or insoluble complexes. For example, sulfides released during the decomposition of organic matter can bind to heavy metals (Z. Chen et al. 2021 ; Kwiatkowska-malina 2018 ; M. Liu et al. 2022 ; Sun et al. 2021 ; Zhang et al. 2021 ). 4.4 Involvement in the production of quality vegetables, choice of urban market gardens in Lubumbashi. In agro-environmental applications, the use of organocalcareous soil improvers has been suggested as a remediation technique for soils contaminated by heavy metals. However, few studies have been carried out in Lubumbashi to confirm or refute these techniques. These techniques are applied to moderately contaminated soils, and their effectiveness depends on the plant species used, and the types and quantities of organic amendments applied to the soil. Our results show that the majority of Lubumbashi's urban gardens are contaminated by heavy metals, mainly copper and cobalt, and that the vegetables produced there are of poor sanitary quality for human health (Mubemba et al. 2014 ; Muimba-Kankolongo et al. 2021 ; Mununga Katebe et al. 2023 ; Muyumba et al. 2019 ). Studies carried out by (Mununga Katebe et al. 2023 ) showed that the level of contamination, pollution and enrichment of each market garden was not the same, as the majority of gardens were contaminated. We therefore recommend that urban market gardens in Lubumbashi with extremely high levels of contamination, as well as those with exceptionally high levels of pollution, use soilless production techniques such as conventional hydroponics or bioponics to guarantee the quality of the vegetables produced in their gardens to safeguard human health (Dhawi 2023 ; Gartmann et al. 2023 ; Magwaza et al. 2020 ; Mai et al. 2023 ). The Congolese government must ensure that planning for urban agriculture in the country takes into account the implications of pollution and high levels of contamination on the potential risk posed by market gardens. To produce in quantity and quality, gardens with very severe levels of pollution and/or contamination should be prioritized for the adoption of new soilless production techniques such as bioponics or conventional hydroponics. In summary, bioponics is a method of growing plants in an aquatic environment, where the roots are immersed in a nutrient solution derived from animal manure or plant waste, with the aim of promoting both the quantity and quality of plant growth (Ezziddine, Liltved, and Seljåsen 2021 ; Bergstrand Karl-Johan and Hakan Asp and Malin Hulberg 2020; Resh 2013 ). In developing countries, where obtaining agricultural inputs is becoming increasingly difficult and expensive, adopting bioponics could prove a sustainable solution for Lubumbashi's poor urban farmers. These farmers need to adopt new techniques to grow vegetables, enabling them to reduce production costs in order to increase producer profits (Nsele et al. 2022 ). 5. Conclusion and outlook The overall aim of this study was to evaluate the effectiveness of applying organocalcium amendments to contaminated soils in order to reduce the mobility and bioavailability of heavy metals. The results indicate that as the amount of organic matter applied to the soil increases, the mobility and bioavailability of metals decreases. In terms of metal uptake by plants, it's clear that treatments receiving 150g + 15g of organic matter and agricultural lime, respectively, absorbed fewer trace metals in the above-ground parts of the crops than treatments with lower amounts of organic matter and agricultural lime, as well as the control, which bioaccumulated more metals in their above-ground biomass. Thus, the daily consumption index of vegetables produced in the urban market garden of Kashamata indicates that the levels of cobalt found in the biomass of four crops exceed the FAO/WHO permissible limit for daily consumption of vegetables for a person of 60 kg body weight. In addition, the daily consumption index was not determined due to insufficient biomass linked to high soil contamination, inhibiting plant growth for the market gardens of Manoah Kinsevere and Chem-Chem, respectively moderately and highly contaminated with copper. Organocalcareous amendments reduce the mobility and bioavailability of metals in the soil for gardens with low levels of trace metal contamination, in contrast to soils with moderate and high levels of trace metal contamination. Hence the importance of using new sustainable technologies to produce vegetables in healthy quantities and quality, and to protect consumer health, in particular bioponics and hydroponic gardening in areas heavily impacted by human activity. Declarations Acknowledgments: The authors would like to thank Engineer Lebeau LAURIN NGOY for his cartographic contributions. We also thank the ONGD REFED and BDD as well as the students who accompanied us in the field for data collection . Author Contributions : Félicien Mununga Katebe: conceptualization, methodology, data analysis and drafting of the manuscript. Jean-Marc Kaumbu Kyalamakasa: methodology, data analysis and critical revision of the manuscript. Gilles Colinet: contribution to drafting, critical revision of the manuscript and project manager. Michel Mpundu Mubemba: methodology, critical revision of the manuscript. M. Haïssam Jijakli: supervision, contribution to drafting, data analysis and critical revision of the manuscript. All authors contributed to the finalization of this manuscript. Data availability: All data used and analyzed in this study will be available from the corresponding author on reasonable request. Funding : This research was funded by the Académie de Recherche et d'Enseignement Supérieur (ARES-CCD) as part of the Research and Development Project entitled : Improving the living conditions of the inhabitants of Lubumbashi by strengthening Urban Agriculture and optimizing ecosystem services in the Democratic Republic of Congo. Declarations: I hereby declare that the contents of this manuscript are original and have not been published elsewhere in whole or in part. The corresponding author has received permission from all authors to submit this manuscript. 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Haissam Jijakli. 2023. “Development of a Simple Bioponic Method Using Manure and Offering Comparable Lettuce Yield than Hydroponics.” Water 15(13): 2335. Tasleem, Samiyah et al. 2023. “Investigation of the Incidence of Heavy Metals Contamination in Commonly Used Fertilizers Applied to Vegetables, Fish Ponds, and Human Health Risk Assessments.” Environmental Science and Pollution Research (0123456789). https://doi.org/10.1007/s11356-023-29480-y . Tran, Thanh Son, Viet Chien Dinh, Thi Anh Huong Nguyen, and Kyoung Woong Kim. 2022. “Soil Contamination and Health Risk Assessment from Heavy Metals Exposure near Mining Area in Bac Kan Province, Vietnam.” Environmental Geochemistry and Health 44(4): 1189–1202. https://doi.org/10.1007/s10653-021-01168-7 . Tuan, Vu Ngoc et al. 2020. “Combination of Multivariate Standard Addition Technique and Deep Kernel Learning Model for Determining Multi-Ion in Hydroponic Nutrient Solution.” Sensors (Switzerland) 20(18): 1–20. 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Wang, Mengyuan et al. 2023. “Influence of Soil Amendments on the Growth and Cadmium Accumulation of Rice in High – Cadmium – Contaminated Agricultural Soils: A Pot Experiment.” Cereal Research Communications (0123456789). https://doi.org/10.1007/s42976-023-00398-y . WRB, IUSS Working Group. 2022. World Reference Base for Soil Resources. International Soil Classification System for Naming Soils and Creating Legends for Soil Maps. Wu, Pingping, Zhibin Guo, Keke Hua, and Daozhong Wang. 2023. “Long – Term Application of Organic Amendments Changes Heavy Metals Accumulation in Wheat Grains by Affecting Soil Chemical Properties and Wheat Yields.” Journal of Soils and Sediments: 2136–47. https://doi.org/10.1007/s11368-023-03473-3 . Wu, Yu Jun et al. 2016. “A Three-Year in-Situ Study on the Persistence of a Combined Amendment (Limestone + sepiolite) for Remedying Paddy Soil Polluted with Heavy Metals.” Ecotoxicology and Environmental Safety 130: 163–70. Xu, Decong et al. 2022. “Effects of Soil Properties on Heavy Metal Bioavailability and Accumulation in Crop Grains under Different Farmland Use Patterns.” Scientific Reports: 1–15. https://doi.org/10.1038/s41598-022-13140-1 . Yang, Qing wei et al. 2011. “Concentration and Potential Health Risk of Heavy Metals in Market Vegetables in Chongqing, China.” Ecotoxicology and Environmental Safety 74(6): 1664–69. http://dx.doi.org/10.1016/j.ecoenv.2011.05.006 . Yin, Bingkui, Liqiang Zhou, Bin Yin, and Liang Chen. 2016. “Effects of Organic Amendments on Rice (Oryza Sativa L.) Growth and Uptake of Heavy Metals in Contaminated Soil.” : 537–46. Yoon, Sungmoon et al. 2023. “Metal(Loid)-Specific Sources and Distribution Mechanisms of Riverside Soil Contamination near an Abandoned Gold Mine in Mongolia.” Journal of Hazardous Materials 443(PB): 130294. https://doi.org/10.1016/j.jhazmat.2022.130294 . Zeng, Fanfu et al. 2015. “Heavy Metal Contamination in Rice-Producing Soils of Hunan Province, China and Potential Health Risks.” International Journal of Environmental Research and Public Health 12(12): 15584–93. Zhang, Qiuguo et al. 2021. “Effect of the Direct Use of Biomass in Agricultural Soil on Heavy Metals.” Environmental Pollution 272: 115989. https://doi.org/10.1016/j.envpol.2020.115989 . Zhao, Haodong et al. 2022. “Comprehensive Assessment of Harmful Heavy Metals in Contaminated Soil in Order to Score Pollution Level.” Scientific Reports (0123456789): 1–13. https://doi.org/10.1038/s41598-022-07602-9 . Zhuang, Ping et al. 2009. “Health Risk from Heavy Metals via Consumption of Food Crops in the Vicinity of Dabaoshan Mine, South China.” Science of the Total Environment 407(5): 1551–61. http://dx.doi.org/10.1016/j.scitotenv.2008.10.061 . Zu, Yanqun et al. 2011. “Factors Affecting Trace Element Content in Periurban Market Garden Subsoil in Yunnan Province, China.” Journal of Environmental Sciences 23(3): 488–96. http://dx.doi.org/10.1016/S1001-0742(10)60401-9 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 06 Sep, 2024 Read the published version in Environmental Monitoring and Assessment → Version 1 posted Editorial decision: Revision requested 23 Feb, 2024 Submission checks completed at journal 21 Feb, 2024 Editor assigned by journal 21 Feb, 2024 First submitted to journal 09 Jan, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3848977","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":274207260,"identity":"93ad9806-ad2c-4924-b260-9e951eae4271","order_by":0,"name":"Félicien Mununga Katebe","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIiWNgGAWjYBADAyBmY2CoAFLMzA1EamEDaTkD0sJIihbGNhCbgBbdGbnHpAt+2Rnzz28+9uDjvNpo/naglh8V23BqMbuRlyY9sy/ZTOIYW7rhzG3Hc2ccZmxg7DlzG4+WHDNp3h5mG4ZjPEDGtmO5DUAtzIxtBLXU28gf4/8m/XfOsdz5RGnh+XHYzOAYD5s0Y0NN7gaCWs68MbbmbThubHgszdyw59iB3I1ALQfx+uV4juFtnj/VhvMOH3724EdNXe6884cPPvhRgVsLGECiAwwOg8kD+NWDwB84q46w4lEwCkbBKBhxAABZHlsnoHEJPgAAAABJRU5ErkJggg==","orcid":"","institution":"1. Centre de Recherches en Agriculture Urbaine (C-RAU), Gembloux Agro-Bio Tech, University of Liege, Passage des Déportés 2, 5030 Gembloux","correspondingAuthor":true,"prefix":"","firstName":"Félicien","middleName":"Mununga","lastName":"Katebe","suffix":""},{"id":274207261,"identity":"9fbdde2a-6e88-4206-883d-8199f486d775","order_by":1,"name":"Gilles Colinet","email":"","orcid":"","institution":"3. Water, Soil \u0026 Plant Exchanges TERRA, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés 2, 5030 Gembloux, Belgium.","correspondingAuthor":false,"prefix":"","firstName":"Gilles","middleName":"","lastName":"Colinet","suffix":""},{"id":274207262,"identity":"633a3786-d1f3-43dd-9163-41714e59ba97","order_by":2,"name":"Jean-Marc Kaumbu Kyalamakasa","email":"","orcid":"","institution":"2. Ecology, Ecological Restoration and Landscape, Agronomy Faculty, University of Lubumbashi, Route Kasapa, Campus Universitaire, Lubumbashi, Congo (Kinshasa).","correspondingAuthor":false,"prefix":"","firstName":"Jean-Marc","middleName":"Kaumbu","lastName":"Kyalamakasa","suffix":""},{"id":274207263,"identity":"46884b46-fb3a-4bd9-b79b-601a316581a7","order_by":3,"name":"Michel Mpundu Mubemba","email":"","orcid":"","institution":"2. Ecology, Ecological Restoration and Landscape, Agronomy Faculty, University of Lubumbashi, Route Kasapa, Campus Universitaire, Lubumbashi, Congo (Kinshasa).","correspondingAuthor":false,"prefix":"","firstName":"Michel","middleName":"Mpundu","lastName":"Mubemba","suffix":""},{"id":274207264,"identity":"2f097693-76e5-4b75-bbf5-693a377fa27c","order_by":4,"name":"M. Haïssam Jijakli","email":"","orcid":"","institution":"1. Centre de Recherches en Agriculture Urbaine (C-RAU), Gembloux Agro-Bio Tech, University of Liege, Passage des Déportés 2, 5030 Gembloux","correspondingAuthor":false,"prefix":"","firstName":"M.","middleName":"Haïssam","lastName":"Jijakli","suffix":""}],"badges":[],"createdAt":"2024-01-09 18:29:45","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3848977/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3848977/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10661-024-13029-8","type":"published","date":"2024-09-06T15:57:39+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":51567152,"identity":"152d41ef-9d3d-4c8a-82b4-51d8571cc354","added_by":"auto","created_at":"2024-02-23 19:39:50","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":44660,"visible":true,"origin":"","legend":"\u003cp\u003eSchematics of the experimental set-up. Legend: D0: no amendments; D1: 150 g of sawdust; D2: 150 g of hen droppings; D3: 75 g of sawdust ± 15 g of lime; D4: 75 g of hen droppings ± 15 g of lime; \u003cem\u003eB. chinensis: Brassica chinensis; B. carinata: Brassica carinata; B. vulgaris: Beta vulgaris; A. vulgaris: Amaranthus vulgaris\u003c/em\u003e; R4: Four replicates.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/9002c77c87a571fcbc4ea83d.jpg"},{"id":51567154,"identity":"1c7e1c5e-73bb-4e3a-8550-650690aa68e8","added_by":"auto","created_at":"2024-02-23 19:39:50","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":158788,"visible":true,"origin":"","legend":"\u003cp\u003eIllustration of sampled urban and peri-urban market gardens in Lubumbashi.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/5cad42bbfe090f50f139a4c9.jpg"},{"id":51567597,"identity":"790fd92c-2a94-4ab8-85a7-390067609605","added_by":"auto","created_at":"2024-02-23 19:55:50","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":83606,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of organocalcareous amendments on the germination rate of four plants grown on contaminated soils. Legend: [A]: \u003cem\u003eA. Vulgaris; \u003c/em\u003e[B]: \u003cem\u003eB. chinesis\u003c/em\u003e; [C]: \u003cem\u003eB. vulgaris\u003c/em\u003e; [D]: \u003cem\u003eB. carinata\u003c/em\u003e; D0: no amendments; D1: 150 g sawdust; D2: 150 g hen droppings; D3: 75 g sawdust ± 15 g lime; D4: 75 g hen droppings ± 15 g lime.\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/0d990e92f4cc7d15bc79ee59.jpg"},{"id":51567158,"identity":"e9b67a03-96f4-41a2-addb-1bb6857c86b9","added_by":"auto","created_at":"2024-02-23 19:39:50","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":100208,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of organocalcareous amendments on the survival rate of \u003cem\u003eA. vulgaris \u003c/em\u003eplants grown on soils contaminated with heavy metals. Legend: D0: no amendments; D1: 150g sawdust; D2: 150g hen droppings; D3:75g sawdust ± 15g lime; D4:75g hen droppings ± 15g lime; -: extreme values; \u003cstrong\u003e-\u003c/strong\u003e: Mean; ◊: Median; [A]: Survival rate at 15 days; [B]: Survival rate at 30 days; [C]: Survival rate at 45 days; [D]: 60-day survival rate; Amend: Types of amendment; Chem: Chem-Chem; Kash: Kashamata Daipen and Mano: Manoah Kinsevere.\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/64078141f953199f0fe3b221.jpg"},{"id":51567155,"identity":"3c187fef-ed8d-4f4b-854c-54490db4b4a6","added_by":"auto","created_at":"2024-02-23 19:39:50","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":101305,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of organocalcareous amendments on the survival rate of \u003cem\u003eB. carinata \u003c/em\u003eplants grown on soil contaminated with heavy metals. Legend: (D0: no amendments; D1: 150g sawdust; D2: 150g hen droppings; D3:75g sawdust ± 15g lime; D4:75g hen droppings ± 15g lime; -: extreme values; \u003cstrong\u003e-\u003c/strong\u003e: Mean; ◊: Median; [A]: Survival rate at 15 days; [B]: Survival rate at 30 days; [C]: Survival rate at 45 days; [D]: 60-day survival rate; Amend: Types of amendment; Chem: Chem-Chem; Kash: Kashamata Daipen and Mano: Manoah Kinsevere.\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/90aa9be3cc57d38b07a3293d.jpg"},{"id":51567270,"identity":"d5f79ac3-4c29-4acd-9524-3b9c44e1bed6","added_by":"auto","created_at":"2024-02-23 19:47:50","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":96246,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of organocalcareous amendments on the survival rate of \u003cem\u003eB. chinensis \u003c/em\u003eplants grown on soil contaminated with heavy metals. Legend: (D0: no amendments; D1: 150g sawdust; D2: 150g hen droppings; D3:75g sawdust ± 15g lime; D4:75g hen droppings ± 15g lime; -: extreme values; \u003cstrong\u003e-\u003c/strong\u003e: Mean; ◊: Median; [A]: Survival rate at 15 days; [B]: Survival rate at 30 days; [C]: Survival rate at 45 days; [D]: 60-day survival rate; Amend: Types of amendment; Chem: Chem-Chem; Kash: Kashamata Daipen and Mano: Manoah Kinsevere.\u003c/p\u003e","description":"","filename":"Figure6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/354160bf4874208bd0dc68dd.jpg"},{"id":51567157,"identity":"f937d827-1912-4963-b847-5b9a7363a7af","added_by":"auto","created_at":"2024-02-23 19:39:50","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":100902,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of organocalcareous amendments on the survival rate of \u003cem\u003eB. vulgaris \u003c/em\u003eplants grown on soil contaminated with heavy metals. Legend: (D0: no amendments; D1: 150g sawdust; D2: 150g hen droppings; D3: 75g sawdust ± 15g lime; D4: 75g hen droppings ± 15g lime; -: extreme values; -: Mean; ◊: Median; [A]: Survival rate at 15 days; [B]: Survival rate at 30 days; [C]: Survival rate at 45 days; [D]: 60-day survival rate; Amend: Types of amendments; Chem: Chem-Chem; Kash: Kashamata Daipen and Mano: Manoah Kinsevere.\u003c/p\u003e","description":"","filename":"Figure7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/30516c75fc52581f46e97aa8.jpg"},{"id":64185984,"identity":"69d1fe5c-5768-455a-be01-14ccc627d7f7","added_by":"auto","created_at":"2024-09-09 16:23:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1876548,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3848977/v1/e5e3dc39-d5d2-4d7e-9301-976e8256b466.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Reducing the risks associated with the ingestion of vegetables grown on soils contaminated with trace metal elements through the application of soil amendments: Results of experiments in Lubumbashi/Democratic Republic of the Congo.","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eLubumbashi, a copper-bearing city, is facing environmental problems of great concern to human health, resulting from ore processing activities and the intensification of mining company activities. These activities have resulted in the contamination of soil, water, plants and air. Substantial quantities of metals, including copper (Cu), cobalt (Co), arsenic (As) and cadmium (Cd), exceed the limits set by the World Health Organization (WHO) and are found in agricultural and residential soils (Alfaro et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; He et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Kinuthia et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Z. Li et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Shutcha et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Zhao et al. \u003cspan citationid=\"CR103\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eContaminated soils transfer metals to plants, interfering with the normal functioning of living organisms (Briffa, Sinagra, and Blundell 2020; Okereafor et al. \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Zu et al. \u003cspan citationid=\"CR105\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Studies carried out in Lubumbashi showed that vegetables produced in gardens and sold on various markets were contaminated with heavy metals ranging, for example, from 13.1 to 39.3 mg/kg for copper and 0.33 to 2.94 mg/Kg for cobalt (Al-Hwaiti and Al-Khashman 2015; S. Khan et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Yang et al. \u003cspan citationid=\"CR98\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The WHO has proposed toxicity thresholds for copper and cobalt of around 10 and 1 mg/kg vegetable dry matter, respectively (Al-Hwaiti and Al-Khashman 2015; S. Khan et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Radwan and Salama \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Yang et al. \u003cspan citationid=\"CR98\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Heavy metals are extremely harmful to living beings, including humans, plants, other terrestrial and aquatic animals (Ahmed et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; I. U. Khan et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Kishore, Malik, and Kumari 2023). Due to heavy metal concentrations found in their urine that were above the toxicity threshold (17.8 ppm for As, 0.75 ppm for Cadmium (Cd), 15.7 ppm for Cobalt (Co), 17.1 ppm for Copper (Cu), 3.17 ppm for Lead (Pb), and 0.028 ppm for Uranium (U), human populations living near ore processing and treatment facilities are exposed to contamination by these heavy metals. The toxicity thresholds proposed by the WHO for arsenic, cadmium, cobalt and uranium in urine are 8, 24, 0, 20, 0, 36 and 0.008 mg/kg respectively. (Banza et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Ilechukwu et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Kampa and Castanas 2008; Song and Li \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Similar conclusions were reached by (Bandara et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Cao et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Ghayoraneh and Qishlaqi 2017; G\u0026oacute;mez-Meda et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; C. Li et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Munir et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Pruvot et al. \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Rai et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Zeng et al. \u003cspan citationid=\"CR101\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) which showed that consumption of cadmium-contaminated rice had caused kidney failure in 5,000 residents of the agricultural region of Sri Lanka.\u003c/p\u003e \u003cp\u003eFaced with such heavy metal contamination, the application of organic or calcareous amendments to metal-contaminated soils is one possible solution for reducing the transfer of metals from soil to plant biomass (C. Li et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Sarwar et al. \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Wan, Lei, and Chen 2016; H. M. Chen et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). These amendments aim to reduce the bioavailability and mobility of metals in the soil and in plants. Copper concentrations in the aerial parts of \u003cem\u003eMicrochloa altera\u003c/em\u003e plants were reduced from (76.3\u0026thinsp;\u0026plusmn;\u0026thinsp;22.1 mg/kg Cu), to (25.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 mg/kg) after addition of organic amendments from water hyacinth (\u003cem\u003eEichhornia crassipes\u003c/em\u003e) and agricultural lime (Jaskulak, Grobelak, and Vandenbulcke 2020; Lin et al. \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Mahar et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Shutcha et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Studies carried out by (Achiba et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Mousavi et al. \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e) showed that the use of organic or limestone amendments to metal-contaminated soils had reduced the mobility of metals in the soil (Cu, Co, Cd, Pb and Zn), but that metal concentrations in vegetables remained above WHO-recommended levels for human consumption of vegetables. (Amin et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Guo et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Nkoh et al., \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2022\u003c/span\u003e)In China, the application of chicken manure mixed with limestone amendments was shown to increase soil pH and significantly reduce the mobility of metals in the soil and their transfer to maize plants. (Cui et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; W. Liu et al. \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Vandyck et al. \u003cspan citationid=\"CR88\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) show that the application of limestone amendments to soils contaminated with heavy metals was responsible for increasing soil pH, cation exchange capacity and the stability of metals in soils, thereby reducing the transfer of metals from the soil to the various plants grown on contaminated soils.\u003c/p\u003e \u003cp\u003eFrom these studies (Gao et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; P. Wu et al. \u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) report that the effective composting of cow dung and green waste composts applied to metal-contaminated soils reduced the mobility of heavy metals in soils and their bioavailability to lettuce (\u003cem\u003eLactuca sativa\u003c/em\u003e) plants. However, most of these studies clearly show that the quantities of both organic and calcareous soil improvers used are very high. The variation in organic matter types and crop types needs to be tested in order to draw the best conclusions applicable to the majority of crops, and to confirm the hypothesis that the use of organic and calcareous soil improvers would reduce the transfer to plants and mobility of metals, especially cobalt and copper, with a view to guaranteeing quality production and nutrition of the vegetables sold and consumed in the city of Lubumbashi. (Franco-Ur\u0026iacute;a et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; S. Khan et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). The aim of this study was to evaluate the effectiveness of different levels of organocalcareous soil improvers in reducing the mobility and bioavailability of trace metals to ensure the quality production of vegetables free from contamination.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1. Study site\u003c/h2\u003e\n \u003cp\u003eThe experiments were carried out between July and September 2019 at the Faculty of Agronomic Sciences, University of Lubumbashi, Democratic Republic of Congo. Lubumbashi\u0026apos;s climate is classified CW6 according to the Koppen classification system, characterized by three distinct seasons: a rainy season from November to March, a dry season from May to September, and two transition months (April and October). Average annual rainfall in the region is estimated at around 1,200 mm. Soils in the Lubumbashi region belong to the ferralitic soil category, with a pH of around 5.9, and are mainly colonized by cupricolous plant species such as \u003cem\u003eCynodon dactylon\u003c/em\u003e, \u003cem\u003eHaumaniastrum katangense\u003c/em\u003e, \u003cem\u003eMicrochloa altera\u003c/em\u003e, \u003cem\u003eImperata cylindrica\u003c/em\u003e and \u003cem\u003eBulbostislis pseudoperenis\u003c/em\u003e. The average annual temperature is 20\u0026deg;C (Malaisse \u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e). The geographical location of this site is specified by the following coordinates: Altitude: 1275 meters, Longitude: 27\u0026deg; 28\u0026apos; 35.7\u0026quot; East, Latitude: 11\u0026deg; 36\u0026apos; 30.6\u0026quot; South.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Experimental design, soil sampling and crop selection\u003c/h2\u003e\n \u003cp\u003e\u003cstrong\u003eExperimental design\u003c/strong\u003e: An experiment was carried out to evaluate the effectiveness of organocalcareous amendments on metal mobility and bioavailability, following a completely randomized factorial design, using chicken droppings, sawdust and agricultural lime. For each treatment, soils from both amended and unamended market gardens were placed in polyethylene pots under glass and repeated four times. Soil samples were taken from each of three market gardens in Lubumbashi (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e), and 500 grams of the sampled soils were kept for laboratory analysis to determine the physico-chemical characteristics of the market garden soils. Treatments included four plant species (\u003cem\u003eBrassica chinensis, Amaranthus vulgaris, Beta vulgaris and Brassica carinata\u003c/em\u003e), five levels of amendment (D0: no amendment; D1: 150g sawdust; D2: 150g chicken droppings; D3: 75g sawdust and 15g agricultural lime; D4: 75g chicken droppings and 15g agricultural lime), as well as three types of urban market gardens (Chem-chem; Manoah Kinsevere and Kashamata).\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eVegetable crops\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eOf the twenty species most widely grown and consumed in the market gardens of Lubumbashi, four vegetable plants (\u003cem\u003eBrassica chinensis, Amaranthus vulgaris, Beta vulgaris and Brassica carinata\u003c/em\u003e) were used in these trials. Improved seeds were purchased from local stores in Lubumbashi. After 60 days of cultivation, all plants were harvested and then dried in an oven to determine the heavy metals in the biomass produced, in order to assess the sanitary quality of the vegetables produced after application of the organocalcareous soil improvers alone or mixed with soil from gardens contaminated with heavy metals.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eSoil\u003c/strong\u003e: the experiments carried out in 2019 were conducted in polyethylene pots containing 2.5 kg of soil and placed under glass in the experimental garden of the Faculty of Agronomic Sciences at the University of Lubumbashi. Three categories of market garden soils were selected: low copper contamination, medium copper contamination and high copper contamination, respectively Kashamata, Manoah Kinsevere and Chem-Chem (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). Soils from the market gardens were sampled to a depth of 20 cm, and five soil samples were taken from each garden. The five samples taken from each garden were mixed to form a composite sample, which was then air-dried, crushed in a porcelain mortar and sieved to 2 mm, then preserved and analyzed in the laboratory to determine the physico-chemical characteristics of the garden soils. According to the International Soil Classification, Lubumbashi soils belong to a group of soils known as Ferralsoil group (WRB 2022).\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eAmendments\u003c/strong\u003e: three types of soil improver were used: chicken droppings, sawdust and dolomitic limestone were applied to soil contaminated with heavy metals. The manure and sawdust were mixed in polyethylene pots, and the agricultural lime was purchased locally. Contaminated soil amendments were applied in polyethylene pots, using locally purchased limestone. The use of limestone amendments to contaminated soils reduces the mobility and bioavailability of metals by increasing soil pH and solubilizing oxides, with the result that trace metals precipitate out. In addition, organic soil improvers, notably chicken droppings and sawdust, were purchased locally in Lubumbashi and composted for 15 days before sowing the crops. Organic amendments are renowned for their richness in organic matter, which positively influences the mobility of trace metal elements in soils by forming organo-metallic complexes, and also raises soil pH levels.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3. Measurement and analysis\u003c/h2\u003e\n \u003cp\u003eThe pH and trace metal content of dried soil samples were determined. Water pH and KCl pH were determined using the potentiometric method (Lasota et al. 2020). Soil samples were ground in a porcelain mortar and sieved using a 2.0 mm mesh sieve. Total metal trace elements in the soil were measured using a portable X-ray fluorescence spectrophotometer (XRF, Olympus Delta Classic Plus, model DCC-4000), as described in (Mpinda et al. \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e). Quantities of exchangeable metals in soils were determined using the 0.01 M CaCl\u003csub\u003e2\u003c/sub\u003e extraction method and measured by atomic absorption spectrophotometry (AAS, VARIAN 220, Agilent Technologies, Santa Clara, CA, USA) (Houba, Uittenbogaard, and Pellen \u003cspan class=\"CitationRef\"\u003e1996\u003c/span\u003e). Chemical analysis of hen droppings and sawdust was carried out at the Agro-pedological laboratory of the Faculty of Agronomic Sciences, University of Lubumbashi. Samples of hen droppings and sawdust were dried at room temperature for 14 days. Trace metal and major element contents were determined in hen droppings and sawdust to determine the nutritional quality of these amendments. Extraction with aqua regia was carried out using the ISO 11466:1995 method. For extraction, the OCC/RD Congo laboratory used 3 g of sample and 28 ml of aqua regia. After extraction, the extract was filtered through paper filters, diluted with demineralized water, then digested for 20 minutes at 175\u0026deg;C in a microwave digestion vessel.\u003c/p\u003e\n \u003cp\u003eA typical calibration method was used to determine trace metals (Cu, Co, Cd, Pb) in the various materials (chicken droppings, sawdust and agricultural lime) using Perkin Elmer\u0026apos;s Optima 7000 DV ICP-OES spectrometer. In order to eliminate soil particles and determine only the metals absorbed by plants, the four vegetables harvested (\u003cem\u003eB. chinensis\u003c/em\u003e, \u003cem\u003eB. carinata\u003c/em\u003e, \u003cem\u003eB. vulgaris\u003c/em\u003e and \u003cem\u003eA. vulgaris\u003c/em\u003e) were washed with tap water to determine the quantities that consumers were able to ingest. These four vegetable biomasses were oven-dried for 24 hours before being ground to powder in an electric grinder. The quantities of heavy metals in the plants were determined by acid mineralization (HNO\u0026thinsp;+\u0026thinsp;HClO\u003csub\u003e34\u003c/sub\u003e ), and measurements were made using an atomic absorption spectrophotometer of the type (AAS, VARIAN 220, Agilent Technologies, Santa Clara, CA, USA) (Adams and Miller \u003cspan class=\"CitationRef\"\u003e1998\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4. Statistical analysis\u003c/h2\u003e\n \u003cp\u003eRaw results for vegetative parameters were subjected to a two-factor analysis of variance (ANOVA), and means were compared using a Tukey test with a significance level of 5%. Data processing was carried out using R x64 4.1.2 and Minitab statistical software.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003e2.5. Physico-chemical characteristics of soils, chicken droppings, sawdust and agricultural lime\u003c/h2\u003e\n \u003cp\u003eThree types of urban market gardens (Chem-Chem; Kashamata and Manoah Kinsevere) were selected, and physico-chemical characteristics were determined in each soil of these gardens (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePhysico-chemical characteristics of soils in Lubumbashi\u0026apos;s urban market gardens. Legend. Cu, Cd, Pb and Zn/dispo: available; ˂0.05: below detection limit ; Nd : Not determined\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMarket Gardens/Heavy metals (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eManoah Kinsevere\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eChem-Chem\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eToxicity threshold (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003epH water\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003epH KCl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6,3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTOC (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3,14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCu/total\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e204\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e535\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1355\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCu/dispo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,026\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,046\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCd/total\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCd/dispo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,013\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,058\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCo/total\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCo/dispo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,069\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePb/total\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e221\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePb/dispo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,427\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,472\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,255\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eZn/total\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e394\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1470\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e300\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eZn/dispo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,643\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,261\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,933\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eThe various organic and calcareous amendments were analyzed to determine their nutritional quality (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The chicken droppings were purchased from an industrial farm located some 15 km from the Faculty of Agronomic Sciences at the University of Lubumbashi. Agricultural lime was purchased from a lime and calcium producer in Likasi, 120 km from Lubumbashi. The sawdust was purchased from the sawmills of the Texaco market, located in the city of Lubumbashi, four kilometers from the Faculty of Agronomic Sciences.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePhysico-chemical characteristics of hen droppings, sawdust and agricultural lime\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"9\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eTypes of amendment\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eMg (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCa (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"6\"\u003e\n \u003cp\u003eHeavy metals (mg/kg)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCu\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCo\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCd\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePb\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eZn\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFe\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAgricultural quicklime (CaCO\u003csub\u003e3\u003c/sub\u003e. MgCO )\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e˂0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHen droppings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7,48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e321,3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e654\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSawdust\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21,6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e2.6. Estimating the daily intake of vegetables.\u003c/h2\u003e\n \u003cp\u003eTo determine the level of heavy metal toxicity in plant biomass, the daily dose was estimated for vegetable consumption in the city of Lubumbashi for an individual over a period of one day, one week or even one month. This index also makes it possible to determine the quantities of metals ingested by a person of known body weight, and is calculated using the following relationship [46, 47] :\u003c/p\u003e\n \u003cdiv id=\"Equa\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e$$\\varvec{E}\\varvec{D}\\varvec{I}=\\frac{{\\varvec{C}}_{\\varvec{m}\\varvec{g}/\\varvec{k}\\varvec{g}}\\times \\varvec{I}\\varvec{n}\\varvec{t}\\varvec{a}\\varvec{k}\\varvec{e}\\left(\\frac{\\varvec{k}\\varvec{g}}{\\varvec{d}\\varvec{a}\\varvec{y}}\\right)}{\\varvec{B}\\varvec{M}\\left(\\varvec{k}\\varvec{g}\\right)}$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eC\u003csub\u003emg\u003c/sub\u003e /kg is the average concentration of the metal in the vegetable, where Intake represents the quantity of vegetables to be consumed per day (kg/day), and finally, BM is the average body weight of the vegetable consumer. The WHO recommends eating 300 to 350 grams of vegetables a day. Then, an average of 0.325 kg/person/day was used to estimate the daily dose of vegetables to be consumed, and a body mass of 60 kg was chosen as the average body weight.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Effects of organocalcareous amendments applied to soils contaminated with trace metallic elements on vegetative parameters.\u003c/h2\u003e\n \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\n \u003ch2\u003e3.1.1. Germination rates of four plants grown on soil contaminated with heavy metals.\u003c/h2\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows that plant germination rates vary from species to species and from garden to garden. Analysis of variance shows significant differences between the different types of organic material used (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). However, the best germination rates of \u003cem\u003eA. vulgaris\u003c/em\u003e seedlings were obtained with the D2\u0026thinsp;\u0026gt;\u0026thinsp;D1\u0026thinsp;\u0026gt;\u0026thinsp;D0\u0026thinsp;\u0026gt;\u0026thinsp;D3\u0026thinsp;\u0026gt;\u0026thinsp;D4 modality. Furthermore, germination rates of \u003cem\u003eB. chinensis\u003c/em\u003e plants and analysis of variance show that the use of organocalcareous amendments significantly influenced plant germination at 7 days, with the best germination rate obtained with modality D1\u0026thinsp;\u0026gt;\u0026thinsp;D0\u0026thinsp;\u0026gt;\u0026thinsp;D2\u0026thinsp;\u0026gt;\u0026thinsp;D3\u0026thinsp;\u0026gt;\u0026thinsp;D4 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). On the other hand, the highest germination rate of B. \u003cem\u003evulgaris\u003c/em\u003e plants was obtained with modality D0\u0026thinsp;\u0026gt;\u0026thinsp;D1\u0026thinsp;\u0026gt;\u0026thinsp;D3\u0026thinsp;\u0026gt;\u0026thinsp;D4\u0026thinsp;\u0026gt;\u0026thinsp;D1, and analysis of variance shows that the application of organocalcareous amendments significantly influenced chard plant germination (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Finally, the highest germination rate of \u003cem\u003eB. carinata\u003c/em\u003e plants was obtained with modality D1\u0026thinsp;\u0026gt;\u0026thinsp;D0\u0026thinsp;\u0026gt;\u0026thinsp;D2\u0026thinsp;\u0026gt;\u0026thinsp;D3\u0026thinsp;\u0026gt;\u0026thinsp;D4, and the analysis of variance shows significant differences between the organocalcareous amendment modalities used (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\n \u003ch2\u003e3.1.2. Survival rate of \u003cem\u003eA. vulgaris\u003c/em\u003e plants \u003cem\u003egrown on\u003c/em\u003e soils contaminated with heavy metals.\u003c/h2\u003e\n \u003cp\u003eAnalysis of variance (ANOVA) revealed that there were significant differences between the market gardens used in terms of plant survival at all observation dates (p˂0.05), unlike the type of amendments applied to the contaminated soils which did not significantly influence amaranth plant survival, however the Kashamata garden had given the highest survival rate unlike the others. Thus, the interaction between market gardens and the type of organic and limestone amendments showed that there were significant differences between treatments in terms of plant survival at all observation dates (p˂0.05), except at day 15 where the ANOVA revealed no significant difference (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eThe survival rate of \u003cem\u003eB. carinata\u003c/em\u003e plants ranged from (0.0\u0026thinsp;+\u0026thinsp;0.00 to 100.0\u0026thinsp;+\u0026thinsp;0.00%), and analysis of variance reveals that there are significant differences (p˂ 0.05) between market gardens in the survival rate of \u003cem\u003eB. carinata\u003c/em\u003e plants at all observation dates, with the highest survival rate obtained in the Chem-Chem garden. The application of organic and limestone amendments had a significant influence on \u003cem\u003eB. carinata\u003c/em\u003e plant survival (p˂0.05), with the best plant survival rate recorded in the Chem-Chem gardens. On the other hand, the combination of organic and limestone amendments had a significant influence on plant survival (p˂0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eThe survival rate of \u003cem\u003eB. chinensis\u003c/em\u003e plants ranged from 0 to 100%, with Analysis of Variance showing significant differences between market gardens at all observation dates (p˂0.05), except at day 15, where ANOVA showed no significant difference. And the best survival rate of B. chinensis plants was obtained with the Chem-Chem garden. Furthermore, analysis of variance showed that there were significant differences between the types of organic and limestone amendments applied (p˂0.05), for \u003cem\u003eB. chinensis seedling\u003c/em\u003e survival at all observation dates except day 15, where ANOVA showed no significant difference. The interaction between vegetable crops and types of organic and limestone amendments significantly influenced (p˂0.05) B. chinensis seedling survival at all observation dates except day 15 th, where ANOVA revealed no significant difference (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eAs for the survival rate of \u003cem\u003eBeta vulgaris\u003c/em\u003e plants, analysis of variance shows that the use of different market gardens significantly influenced the survival of B. vulgaris plants at all observation dates (p˂0.05), with the highest survival rate obtained in the Manoah market garden. In all cases, organocalcareous soil amendments significantly influenced the survival rate of \u003cem\u003eB. vulgaris\u003c/em\u003e seedlings (p˂0.05) and, the best seedling survival rate was obtained with the modalities (D1 and D0). However, the interaction between market gardens and organocalcareous amendment types significantly influenced \u003cem\u003eB. vulgaris\u003c/em\u003e seedling survival at all observation dates, except at day 15 where ANOVA revealed no significant difference (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Effects of organocalcareous soil improvers on the pH of soils contaminated by heavy metals.\u003c/h2\u003e\n \u003cp\u003eTable\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows that the application of organocalcareous soil improvers in different market gardens significantly influenced soil pH, irrespective of the plant species grown. ANOVA revealed that the use of three market gardens significantly influenced soil pH. However, the interaction between organocalcareous soil improvers and market gardens also significantly influenced soil pH for all plant species used (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab5\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffects of organic amendments on the pH of soils contaminated with heavy metals. Legend: (D0: no amendments; D1: 150 g sawdust; D2: 150 g hen droppings; D3: 75 g sawdust\u0026thinsp;\u0026plusmn;\u0026thinsp;15 g lime; D4: 75 g hen droppings\u0026thinsp;\u0026plusmn;\u0026thinsp;15 g lime; black dot: extreme values; horizontal bar: mean; diamond: median.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"6\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGardens\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAmendments\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epH \u003cem\u003eA. vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epH \u003cem\u003eB. chinensis\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epH \u003cem\u003eB. vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epH \u003cem\u003eB. carinata\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChemchem\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003efg\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChemchem\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003efgh\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChemchem\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChemchem\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06d\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChemchem\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.46\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManoah\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.66\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.55\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.60\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManoah\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003egh\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.79\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.58\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManoah\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManoah\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.01\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003eefg\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.84\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003edef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManoah\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003eefg\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.97\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.47\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.56\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.97\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.33\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eEffets sites (p-value)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eEffets mati\u0026egrave;res organiques (p-value)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eInteraction Sites x M.O (p-value)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eEstimated daily consumption of vegetables produced in Lubumbashi\u0026apos;s urban market gardens was carried out for the Kashamata market garden, a garden with low copper contamination. In contrast, data from the Chem-Chem and Manoah Kinsevere market gardens are not presented in Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e, as the majority of treatments applied did not result in sufficient biomass for analysis of metal concentration. This is due to moderate and high levels of trace metal contamination. In the Kashamata vegetable garden, the daily vegetable consumption indices are below the FAO/WHO limits for daily vegetable consumption per person for most trace metals (Cu, Cd and Pb).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab6\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDetermination of daily consumption of leafy vegetables in the city of Lubumbashi (mg/60 Kg/day). Legend: ND: not determined\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"7\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCrop types\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eGardens\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eTypes of amendment\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eTrace metals\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCd\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCu\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePb\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCo\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eLimit WHO/FAO\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,06\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,214\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,055\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAmaranthus vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,023\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,375\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,449\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAmaranthus vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,182\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,102\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAmaranthus vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAmaranthus vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,461\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,013\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,056\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAmaranthus vulgaris\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,805\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,023\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,101\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica chinensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,231\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,177\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica chinensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,223\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica chinensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,208\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,027\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica chinensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,389\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,029\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica chinensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,288\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica carinata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,009\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,363\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,326\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica carinata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,385\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,052\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica carinata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,055\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,119\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica carinata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,526\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,029\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,063\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBrassica carinata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,947\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,036\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,086\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBeta vulgarus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,465\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBeta vulgarus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,346\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,008\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,084\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBeta vulgarus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0,779\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,029\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0,075\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBeta vulgarus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eBeta vulgarus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKashamata\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eHowever, with regard to cobalt, the results indicate that the four vegetables cannot be consumed by the population of Lubumbashi, as the high quantities of metals found in the leaves exceed the limits set by the FAO/WHO for the daily consumption of vegetables for a person of 60 kg body weight. In addition, the application of organocalcareous amendments influenced the daily consumption index. Treatment D4 proved more effective than other treatments with fewer amendments, following the order of accumulation D4\u0026thinsp;\u0026gt;\u0026thinsp;D3\u0026thinsp;\u0026gt;\u0026thinsp;D2\u0026thinsp;\u0026gt;\u0026thinsp;D1\u0026thinsp;\u0026gt;\u0026thinsp;D0.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Level of soil contamination and/or pollution in market gardens in Lubumbashi.\u003c/h2\u003e \u003cp\u003eIn Lubumbashi, not all soils present the same risks of metal contamination and/or pollution. In view of the levels found in market garden soils, which show that soils located close to mining activities have extremely high levels, often exceeding recommended toxicity thresholds, in contrast to soils where mining is not present (Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Muimba-Kankolongo et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mununga Katebe et al. \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Soil contamination results from a combination of various sources, including natural sources and anthropogenic activities impacting the environment. Agricultural soils in the vicinity of these mineral extraction companies are known to be the most contaminated by trace metals, mainly due to the intensity of their operations (Abiya SE 2019; Muimba-Kankolongo et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Sonter, Ali, and Watson 2018; Tran et al. \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Yoon et al. \u003cspan citationid=\"CR100\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) than garden soils away from human activities. Our results corroborate those of (Hu et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) carried out in Canada, which revealed that the mining industry was responsible for heavy metal contamination of river water through the use of land application sludge in agriculture.\u003c/p\u003e \u003cp\u003eIn addition, mining companies are responsible for the contamination and pollution of agricultural soils (Candeias et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Giri, Singh, and Mahato 2017; Luo et al. \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Mirzaei Aminiyan et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; J. Wang et al. \u003cspan citationid=\"CR92\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). This shows that areas close to mining activities have been contaminated by dust, effluent and water containing metal particles. Nevertheless, this contamination has had a disruptive impact on the environment, crops and agricultural soils (He et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Ma et al. 2015; D. Wang et al. \u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In Lubumbashi, this phenomenon was exacerbated by the liberalization of the Soci\u0026eacute;t\u0026eacute; g\u0026eacute;n\u0026eacute;rale des carri\u0026egrave;res et mines (GECAMINES), which led to the creation of several mining companies and consequently contaminated the soils of market gardens located near the mining companies. However, different levels of soil contamination and/or pollution may require different remediation techniques. Soils with low or moderate levels of trace metal contamination may require specific approaches such as phytoremediation techniques, but where the level of contamination in market garden soils is higher, it is advisable to switch to other cultivation approaches such as bioponics or hydroponics (Guo et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Szekely, Zeaiter, and Jijakli 2023).\u003c/p\u003e \u003cp\u003e \u003cb\u003e4.2 Reducing the bioavailability of heavy metals and estimating the daily consumption of vegetables for a high-quality human diet.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eOrganocalcareous soil improvers are proposed as techniques for reducing the transfer of metals from soil to plants. Studies conducted by (Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Shutcha et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2015\u003c/span\u003e)have shown that organocalcareous amendments reduce the mobility and bioavailability of trace metals (Frick et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Khoshru et al. \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Narayanan and Ma 2023; Sarwar et al. \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; H. Wang et al. \u003cspan citationid=\"CR91\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Y. J. Wu et al. \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). However, the quantities of amendments are still very large. Our results indicate that the application of organocalcareous amendments reduced the transfer of trace metal elements from the soil to plants, on the one hand by creating chelates of trace metal elements, but on the other hand, they made the soils slightly acidic (Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Shutcha et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). With regard to the daily vegetable consumption index, our results reveal persistent problems, as the consumption indices exceed the limits set by the FAO/WHO for daily vegetable consumption, particularly with regard to cobalt for vegetables from the Kashamata market garden (Abuzed Sadee and Jameel Ali 2023; Adefa and Tefera 2020; Langunu et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Tasleem et al. \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). This phenomenon could be explained by the fact that the soils of Haut-Katanga province in general, and the city of Lubumbashi in particular, have a pedogeochemical background enriched in copper and cobalt. In addition, the poor management of quarries and mines, as well as the discharge of effluents rich in metallic particles and aerosols containing dust, can contribute to the propensity of this environmental scourge. (Bogaert, Colinet, and Mahy 2018; Shengo et al. \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Shutcha et al. \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). The recommended quantities of vegetables (300 grams/60kg of an adult) could prove very dangerous for children whose weight is less than that of adults, given the danger that the city of Lubumbashi presents in terms of copper and cobalt production. On the other hand, if we consider the other metallic trace elements (Cu, Pb and Cd), the daily vegetable consumption index indicates that these vegetables can be consumed up to three times a week without exceeding the limits set by the FAO/WHO for daily vegetable consumption for a person of 60 kg body weight (Cherfi et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Zhuang et al. \u003cspan citationid=\"CR104\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAccording to the International Soil Classification, Lubumbashi soils belong to the category of ferralitic soils characterized by the presence of over 20% clay in soil profiles A-C and A-B-C, mainly composed of Kaolinite, as well as iron and aluminum oxides (G. Chen et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). However, the clay component is mainly composed of kaolinite and is mixed with significant amounts of free oxides, resulting in a SiO2/Al2O3 ratio less than or equal to 2. Applying organocalcic soil improvers to ferritic soils contaminated with trace metal elements improves soil fertility and offers a high capacity for immobilizing trace metal elements in the soil. This is due to the high reactivity of dissolved and colloidal iron in ferralsols, mixed with other elements such as Si, Ca, Mg, Na and K introduced by the application of organo-calcium amendments on metal-contaminated soils, destabilizing kaolinite and allowing the formation of 2:1 clay minerals. These minerals then reduce the bioavailability of metals to plants (G. Chen et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Mohamed, Ahamadou, and Li \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003e4.3 Effect of organocalcareous soil improvers on growth parameters of four vegetable crops grown on soil contaminated with heavy metals in Lubumbashi.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe use of organocalcareous amendments aims to increase soil pH and reduce the mobility and bioavailability of metals in agricultural soils (Alam et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; He et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Tuan et al. \u003cspan citationid=\"CR86\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Yin et al. \u003cspan citationid=\"CR99\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). However, analysis of variance indicates that the use of various market gardens did not significantly influence amaranth plant emergence rates. This could be attributed to the low nitrogen content of the organic matter supplied to the plants (Felix, Charles, and Wang 2022; Xu et al. \u003cspan citationid=\"CR97\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Similar conclusions were drawn by (Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e) who found that the application of organocalcareous amendments to agricultural soils had no significant effect on the growth of \u003cem\u003eA. vulgaris\u003c/em\u003e amaranth plants. Furthermore, amaranth plant survival was significantly influenced by market garden types, while organic matter did not significantly influence amaranth plant survival at all observation dates. Similar results were reported by (Ullah et al. \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; M. Wang et al. \u003cspan citationid=\"CR91\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) who found that compost application on metal-contaminated soils did not significantly influence germination and survival of \u003cem\u003eBrassica juncea\u003c/em\u003e plants in the Spanish region of Aznalc\u0026oacute;llar (Alam et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Our results can be explained by the fact that during the decomposition of organic matter, specific organic compounds can release substances that have the ability to immobilize heavy metals by forming precipitates or insoluble complexes. For example, sulfides released during the decomposition of organic matter can bind to heavy metals (Z. Chen et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Kwiatkowska-malina \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; M. Liu et al. \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Sun et al. \u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Zhang et al. \u003cspan citationid=\"CR102\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e4.4 Involvement in the production of quality vegetables, choice of urban market gardens in Lubumbashi.\u003c/h2\u003e \u003cp\u003eIn agro-environmental applications, the use of organocalcareous soil improvers has been suggested as a remediation technique for soils contaminated by heavy metals. However, few studies have been carried out in Lubumbashi to confirm or refute these techniques. These techniques are applied to moderately contaminated soils, and their effectiveness depends on the plant species used, and the types and quantities of organic amendments applied to the soil. Our results show that the majority of Lubumbashi's urban gardens are contaminated by heavy metals, mainly copper and cobalt, and that the vegetables produced there are of poor sanitary quality for human health (Mubemba et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Muimba-Kankolongo et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mununga Katebe et al. \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Muyumba et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Studies carried out by (Mununga Katebe et al. \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) showed that the level of contamination, pollution and enrichment of each market garden was not the same, as the majority of gardens were contaminated. We therefore recommend that urban market gardens in Lubumbashi with extremely high levels of contamination, as well as those with exceptionally high levels of pollution, use soilless production techniques such as conventional hydroponics or bioponics to guarantee the quality of the vegetables produced in their gardens to safeguard human health (Dhawi \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Gartmann et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Magwaza et al. \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Mai et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The Congolese government must ensure that planning for urban agriculture in the country takes into account the implications of pollution and high levels of contamination on the potential risk posed by market gardens. To produce in quantity and quality, gardens with very severe levels of pollution and/or contamination should be prioritized for the adoption of new soilless production techniques such as bioponics or conventional hydroponics.\u003c/p\u003e \u003cp\u003eIn summary, bioponics is a method of growing plants in an aquatic environment, where the roots are immersed in a nutrient solution derived from animal manure or plant waste, with the aim of promoting both the quantity and quality of plant growth (Ezziddine, Liltved, and Selj\u0026aring;sen \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Bergstrand Karl-Johan and Hakan Asp and Malin Hulberg 2020; Resh \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In developing countries, where obtaining agricultural inputs is becoming increasingly difficult and expensive, adopting bioponics could prove a sustainable solution for Lubumbashi's poor urban farmers. These farmers need to adopt new techniques to grow vegetables, enabling them to reduce production costs in order to increase producer profits (Nsele et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusion and outlook","content":"\u003cp\u003eThe overall aim of this study was to evaluate the effectiveness of applying organocalcium amendments to contaminated soils in order to reduce the mobility and bioavailability of heavy metals. The results indicate that as the amount of organic matter applied to the soil increases, the mobility and bioavailability of metals decreases.\u003c/p\u003e \u003cp\u003eIn terms of metal uptake by plants, it's clear that treatments receiving 150g\u0026thinsp;+\u0026thinsp;15g of organic matter and agricultural lime, respectively, absorbed fewer trace metals in the above-ground parts of the crops than treatments with lower amounts of organic matter and agricultural lime, as well as the control, which bioaccumulated more metals in their above-ground biomass. Thus, the daily consumption index of vegetables produced in the urban market garden of Kashamata indicates that the levels of cobalt found in the biomass of four crops exceed the FAO/WHO permissible limit for daily consumption of vegetables for a person of 60 kg body weight. In addition, the daily consumption index was not determined due to insufficient biomass linked to high soil contamination, inhibiting plant growth for the market gardens of Manoah Kinsevere and Chem-Chem, respectively moderately and highly contaminated with copper. Organocalcareous amendments reduce the mobility and bioavailability of metals in the soil for gardens with low levels of trace metal contamination, in contrast to soils with moderate and high levels of trace metal contamination. Hence the importance of using new sustainable technologies to produce vegetables in healthy quantities and quality, and to protect consumer health, in particular bioponics and hydroponic gardening in areas heavily impacted by human activity.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u0026nbsp;\u003c/strong\u003eThe authors would like to thank Engineer Lebeau LAURIN NGOY for his cartographic contributions. We also thank the ONGD REFED and BDD as well as the students who accompanied us in the field for data collection\u003cstrong\u003e.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e: F\u0026eacute;licien Mununga Katebe: conceptualization, methodology, data analysis and drafting of the manuscript. Jean-Marc Kaumbu Kyalamakasa: methodology, data analysis and critical revision of the manuscript. Gilles Colinet: contribution to drafting, critical revision of the manuscript and project manager. Michel Mpundu Mubemba: methodology, critical revision of the manuscript. M. Ha\u0026iuml;ssam Jijakli: supervision, contribution to drafting, data analysis and critical revision of the manuscript. All authors contributed to the finalization of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability:\u0026nbsp;\u003c/strong\u003eAll data used and analyzed in this study will be available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding :\u0026nbsp;\u003c/strong\u003eThis research was funded by the Acad\u0026eacute;mie de Recherche et d\u0026apos;Enseignement Sup\u0026eacute;rieur (ARES-CCD) as part of the Research and Development Project entitled : Improving the living conditions of the inhabitants of Lubumbashi by strengthening Urban Agriculture and optimizing ecosystem services in the Democratic Republic of Congo.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclarations:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eI hereby declare that the contents of this manuscript are original and have not been published elsewhere in whole or in part. The corresponding author has received permission from all authors to submit this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have read and understood the declaration on \u003csup\u003e\u0026laquo;\u0026nbsp;\u003c/sup\u003ethe ethical responsibilities of authors\u003csup\u003e\u0026raquo;\u003c/sup\u003e and have complied where appropriate with the declaration on \u003csup\u003e\u0026laquo;\u0026nbsp;\u003c/sup\u003ethe ethical responsibilities of authors\u003csup\u003e\u0026raquo;\u003c/sup\u003e indicated in the instructions to authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbiya SE, Odiyi BO. 2019. \u0026ldquo;Assessment of Heavy Metal Pollution in a Gold Mining Site in Southwestern Nigeria.\u0026rdquo; Journal of Biotechnology \u0026amp; Bioresearch 1(4): 30\u0026ndash;35.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbuzed Sadee, Bashdar, and Rasul Jameel Ali. 2023. \u0026ldquo;Determination of Heavy Metals in Edible Vegetables and a Human Health Risk Assessment.\u0026rdquo; \u003cem\u003eEnvironmental Nanotechnology, Monitoring and Management\u003c/em\u003e 19(March 2022): 100761. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.enmm.2022.100761\u003c/span\u003e\u003cspan address=\"10.1016/j.enmm.2022.100761\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAchiba, W. 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These problems include contamination of agricultural and residential soils, river and well water, the atmosphere and vegetables. This study evaluates the effectiveness of organocalcareous soil improvers applied to heavy metal-contaminated soils in reducing the mobility and bioavailability of heavy metals. Trials were conducted under glass at the Faculty of Agronomic Sciences, University of Lubumbashi, using a randomized factorial design with four replications. Treatments included four plant species (\u003cem\u003eBrassica chinensis, Amaranthus vulgaris, Beta vulgaris and Brassica carinata\u003c/em\u003e), five levels of amendment (D0: no amendment; D1: 150g sawdust; D2: 150g chicken droppings; D3: 75g sawdust and 15g agricultural lime; D4: 75g chicken droppings and 15g agricultural lime), and three types of urban market gardens (Chem-chem; Manoah Kinsevere and Kashamata). The results reveal that the soil and plant biomass of four vegetables are contaminated with metals, with the daily consumption index of vegetables produced on the soils of the Kashamata garden with low copper contamination exceeding the limits authorized by the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) for daily vegetable consumption for a person of 60 kilograms body weight. The daily consumption index was not determined due to insufficient biomass linked to high soil contamination, inhibiting plant growth for the market gardens of Manoah Kinsevere and Chem-Chem, soils moderately and highly contaminated with copper, respectively. However, these vegetables remain unfit for human consumption, underlining the need to adopt new soilless production techniques such as conventional hydroponics or bioponics in areas heavily impacted by anthropogenic activities.\u003c/p\u003e","manuscriptTitle":"Reducing the risks associated with the ingestion of vegetables grown on soils contaminated with trace metal elements through the application of soil amendments: Results of experiments in Lubumbashi/Democratic Republic of the Congo.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-23 19:39:45","doi":"10.21203/rs.3.rs-3848977/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-02-23T18:10:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-02-22T01:39:04+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-02-22T01:39:04+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Monitoring and Assessment","date":"2024-01-09T18:17:20+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-monitoring-and-assessment","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"emas","sideBox":"Learn more about [Environmental Monitoring and Assessment](http://link.springer.com/journal/10661)","snPcode":"10661","submissionUrl":"https://submission.nature.com/new-submission/10661/3","title":"Environmental Monitoring and Assessment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f6b9063b-e597-499e-906a-450165097351","owner":[],"postedDate":"February 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-09-09T16:14:10+00:00","versionOfRecord":{"articleIdentity":"rs-3848977","link":"https://doi.org/10.1007/s10661-024-13029-8","journal":{"identity":"environmental-monitoring-and-assessment","isVorOnly":false,"title":"Environmental Monitoring and Assessment"},"publishedOn":"2024-09-06 15:57:39","publishedOnDateReadable":"September 6th, 2024"},"versionCreatedAt":"2024-02-23 19:39:45","video":"","vorDoi":"10.1007/s10661-024-13029-8","vorDoiUrl":"https://doi.org/10.1007/s10661-024-13029-8","workflowStages":[]},"version":"v1","identity":"rs-3848977","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3848977","identity":"rs-3848977","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}