Assessing Health Risk Associated with Uranium in Rietspruit Water, Far West Rand Goldfield, South Africa

Assessing Health Risk Associated with Uranium in Rietspruit Water, Far West Rand Goldfield, South Africa | 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 Assessing Health Risk Associated with Uranium in Rietspruit Water, Far West Rand Goldfield, South Africa Iyioluwa Busuyi Raji, Emile Hoffmann, Ewald Erasmus, Adeline Ngie, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1177732/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Uranium, U, as a toxic element has detrimental radiological and chemical impacts on human health when ingested at elevated concentration in water. The establishment of gold mining operations upstream to the Rietspruit is assumed to be a source of uranium into this water body which flows through residential and agricultural land. Water samples from the stream were collected and analysed using inductively coupled plasma mass spectrometry to determine the concentration of U. Uranium concentrations above South African regulatory limit were recorded in the stream water which is used for domestic, agricultural and religious activities as observed during field visits. Results from calculations showed that the maximum annual effective dose within this mining environment was above 1 mSv/year for all age groups. Furthermore, the probability of radiological risk is lower than the chemical risk which is due to the ingestion of U in the Rietspruit water. The chemical risk analysis showed that within 24 km of this mining environment, stream users are in danger of U chemical toxins therefore, it is important to educate the stream users about their health risk of U and recommend adequate interventions by relevant government agencies to this effect. Health Policy Internal Medicine Toxicology uranium dose exposure pathways cancer risk hazard gold mining Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction The quality of most South African water has deteriorated over the years which poses serious health risks to humans and livestock (WWF-SA, 2016 ). The main source of South Africa water input is rainfall, however, with annual average rainfall below 50% of world average rainfall, the country is regarded as a water-scarce country. Despite the scarcity, 62% of South Africa’s water is used for irrigation, 11% is used for mining and industrial use (WWF-SA, 2016 ; DWAS, 2020). Poor communities like residents of informal settlements have the extreme problem of insufficient water services and consequent water-related ailments. This is because they depend on nearby surface water to meet their water needs. In gold mining areas, most of the surface water was polluted with heavy metals, uranium inclusive. Uranium, U, has been reported to have health impacts on humans exposed to the element (Adams et al., 2010 ; ATSDR, 2014 ; Bjørklund et al., 2020 ; Bleise, Danesi, & Burkart, 2003 ; Winde, 2011 ; Zamora, Tracy, Zielinski, Meyerhof, & Moss, 1998 ). Depending on the solubility of the uranium compound, exposure route, and concentration, kidneys, lungs, bones are among the targeted vitals that could be damaged by U (ATSDR, 2014 ; Dewar, 2019 ; Keith et al., 2013 ; WHO, 2001 ). Uranium is mined in South Africa in most cases as the by-product of gold mining (Ford, 1993 ; Krige, 1966 ; Tutu, Cukrowska, McCarthy, Mphephu, & Hart, 2003 ; Winde & de Villiers, 2002 ). High concentrations of U have been found within gold mines in water and sediment (Durand, 2012 ; Fashola, Ngole-Jeme, & Babalola, 2016 ; Caspah Kamunda, Mathuthu, & Madhuku, 2016 ; Raji, Hoffmann, Ngie, & Winde, 2021 ). Gold mining has been a contributing factor to the economy of South Africa, however, large volumes of mine wastes have been deposited as a result (Fedderke & Pirouz, 2002 ; McCarthy, 2011 ). In the Witwatersrand Basin, one of the richest gold deposits worldwide (Tutu, McCarthy, & Cukrowska, 2008 ), high concentrations of U have been recorded in some of the mined gold reefs. About 70 years ago, the Far West Rand became the first goldfield in South Africa where commercial production of U was established (Coetzee, Winde, & Wade, 2006 ). Winde ( 2001 ) reported an average U concentration of about 110 mg/kg in gold tailings across seven goldfields of the Witwatersrand Basin. Winde ( 2004 ) concluded that for each ton of gold produced, more than 10 tons of U were brought to the earth’s surface. Mined gold reefs are therefore regarded as the primary source of U (Winde & Sandham, 2004 ). Other sources of U pollution include mine waste deposits such as slime dams and mine dumps often located close to streams or rivers. In many cases, these waste deposits are the primary source of U pollution of the nearby water bodies. The process includes the transport of dissolved U via seepage into underlying alluvial aquifers (Winde & van der Walt, 2004 ) and of U-bearing tailings particles by wind and water erosion (Winde & Sandham, 2004 ). Uranium can be emitted from point sources or from non-point (diffuse) sources. Point source pollution includes the discharge of fissure and processed water through canals and pipelines into nearby streams or dams as witnessed in this study. Despite the fact that the mine has been decommissioned about 5 years ago, dewatering of underground shafts is still ongoing. Another example of point source pollution is the storm-water run-off from contaminated mining environments such as slime dams, retention dams, rock and sand dumps. A typical example of diffuse sources of pollution includes seepage from slime dams, run-off from mine dumps. Uranium is released into the environment in a number of ways which include erosion of slime dams by wind and water leading to eroded slimes settling on dams, wetland, irrigation channels and agricultural land etc. (Coetzee et al., 2006 ). In addition, there are spillages of tailings associated with burst pipelines, partial dam failures etc. High concentrations of U have been found several kilometres from the mining site in river sediment, wetlands and dams as a result of precipitation, adsorption, co-precipitation and bioaccumulation (Winde, Wade, & van der Walt, 2004 ). Wetlands and dams have been identified as sinks for U and other toxic heavy metals such as mercury, lead, cadmium, arsenic (Coetzee, Wade, & Winde, 2002 ; Ross & Dudel, 2008 ; Schöner, Noubactep, Büchel, & Sauter, 2009 ). Raji et al., ( 2021 ) recorded high concentrations of the aforementioned heavy metals above the acceptable limit in a wetland and dam located about 3 km and 6 km respectively away from a mining site. These sites can be a secondary source of U pollution and other heavy metals if there is a change in the water chemistry which could be influenced by the water’s pH, electric conductivity, redox state and seasonal changes (from winter to summer). The focus of this study is on the Rietspruit, a small stream draining the south-eastern part of the Far West Rand (FWR) goldfield that is impacted by mining-related water pollution. The study explores the main pathways of U entering the Rietspruit system including the leaching of U from mine wastes, aqueous transport of dissolved uranium from on-site sources and mechanisms governing the transport of dissolved U within the fluvial system which include immobilisation and remobilisation to and from fluvial sediments, respectively. Uranium is released from mine waste during a rain event and transported to Peter Wright dam (Rietspruit headwater). A concentration of about 52.7 µg/l of U was recorded in the fissure water discharged by the mine into the PW dam. (Raji et al., 2021 ). According to Kritzinger ( 2017 ), about 68 Ml of fissure water is pumped into the PW dam per day, this means the amount of U discharged into the PW dam is about 52 700 mg/l of U per day. Thus, the discharge of fissure water into the PW dam is the most significant U source into the Rietspruit. The outflow from the PW dam into the Rietspruit makes the Rietspruit a perennial one. Observations during field sampling indicated that the Rietspruit water is used for drinking, cooking, bathing (especially by the residents of informal settlements within the area and religious worshippers) and animal watering and dam water is used for irrigation of farmland. Plant’s uptake of U from the soil could be a result of air pollution from slime dams and water used to irrigate such plants (Anke, Seeber, Müller, Schäfer, & Zerull, 2009 ; Gupta & Walther, 2020 ). Due to human exposure witnessed during fieldwork, and the lack of information on the level of U these people could be exposed to, it is imperative to assess potential health risks associated with the concentration of U found in the Rietspruit. This study will be used to sensitize the locals about the danger involved with the use of the water for domestic, agricultural and religious purposes. Since the most regular human exposure pathway witnessed was the ingestion of the water from the stream, both carcinogenic and non-carcinogenic risk assessments were carried out. The objectives of this study are; 1) To determine the concentration of U in the Rietspruit water. 2) To assess the health risk posed by U level in the Rietspruit water. 3) Propose general recommendations. Material And Method Study area The Rietspruit is located in Gauteng Province, South Africa about 1 km away from a gold and uranium mine. The gold and uranium mine (coordinate: 26°21'46"S 27°42'52"E) was operational for about 56 years before it was decommissioned in August 2016 discharge their fissure and process water into the Peter Wright dam (PW dam). The outflow from the PW dam is the source of the Rietspruit. It is believed that the Rietspruit will be a non-perennial river if the mine should stop discharging water into the PW dam. The river flows for about 60 km southwardly before joining the Vaal river (Figure 1 ). The associated drainage region name is C22H according to the Department of Water Affairs and Sanitation (Figure 2 ) comprising a catchment area of about 454 km 2 . Contributing tributaries include the Leeuspruit, Evaton Rietspruit and Klein-Rietspruit. While Leeuspruit is also polluted with U as a result of a gold mine located upstream of the confluence with Rietspruit, the Evaton Rietspruit and Klein-Rietspruit are not polluted as they drain areas without mining activity. The Leeuspruit is located in the C22J Quaternary Catchment (Figure 2 ) draining some 668.7 km 2 (Department of Water Affairs and Sanitation, 2011). As a result of the absence of mining or industrial activities upstream of both the Evaton Rietspruit and Klein-Rietspruit, the concentration of U in the water of these streams was used as the natural background concentration of U. Farms are located within the area and most of them depend on the water from the Rietspruit for irrigation. The climate of the study area is temperate, defined by moderately cold winters (April to August) and hot summers (October to March). Annual rainfall occurs between October to March and with an average of about 664 mm. Evaporation is about twice the annual rainfall (about 1700 mm). In winter, the average temperature is 13 o C and 24 o C in summer (Caspah Kamunda et al., 2016 ). The Ezulwini gold and uranium mine is located in the Witwatersrand Basin, a sedimentary basin of about 2.7 billion years of age containing a stratigraphic sequence about 6 km thick made of quartzites, conglomerates and lava (Phillips & Law, 2000 ). Underlying the mine, gold is found in the upper Elsburg in the form of native gold and is associated with sulphide minerals (e.g pyrite). Also, gold is found in the middle Elsburg reefs associated with pyrite underlying the mine and U is mined in the middle Elsburg reef (Kritzinger, 2017 ) and it is found in the form of uraninite. Field work A total of 28 water samples were collected on the 28th of August 2020 across the entire length of the Rietspruit (Figure 2 ). Water samples were collected in a 100 ml water bottle below the water surface. The water bottle was rinsed three times with the river water and decanted away from the sampled site. Water samples were taken in the middle of the river, depending on the depth of the site, to avoid sampling the banks of the river. Each water bottle was labelled accordingly and kept in a cooler box. The samples were all taken to the laboratory the following day for chemical analysis. Samples were analysed in the laboratory to determine the concentration of U using inductively coupled plasma mass spectrometry (ICP-MS). Lab analysis The chemical analysis of the water samples was done at the Eco-analytical laboratory in North-West University, Potchefstroom Campus, South Africa. Each water sample was first filtered using a 0.45 µm pre-nylon sieve to remove suspended particles. 1 mL of the filtered water was measured and 9 mL of nitric acid was added to remove any dissolved organic material in the water. An Agilent 7500 CE ICP-MS with Collision Reaction Cell (CRC) technology for interference removal was used to determine the concentration of U in the water. In order to achieve a quantitative result, the instrument is calibrated using ULTRASPEC certified custom mixed multi-element stock standard (De Bruyn Spectroscopic Solutions, Midrand, South Africa) solutions containing all the elements of interest. Exposure assessment According to the US EPA ( 1992 ), exposure assessment can be defined as the determination of the magnitude, frequency and duration of exposure and exposure dose. Exposure assessment includes identification of all important sources of pollutant, routes of exposure (exposure pathways), potentially exposed population, mechanism of pollutant transportation, quantification of exposure, toxicity assessment of pollutant, and risk characterisation. Exposure assessment is one of the most essential steps in human health risk assessment, hazard identification, dose-response assessment and risk characterization are the other steps (NRC, 2009 ). Source of uranium pollution The main source of uranium, as a contaminant of concern, in the Rietspruit is the Ezulwini Gold and Uranium mine (Figure 3 ). Slimes and waste rock are deposited on the surface. Oxidised mine wastes release U when in contact with water (in the form of rain, pore-water and seepage), which then runs-off into PW dam inflow. The mine also discharges fissure water with elevated concentration of U into PW dam, Rietspruit headwater. Fissure water is mainly water from underground mine workings that was in contact with oxidised uranium ore (Winde, 2004 ). Another source of U in the Rietspruit includes the settling of tailings materials transported by wind to surface water. Exposure pathway In this study, the pathways include the usage of the water for domestic, religious and agricultural purposes. Domestic and religious activities observed in the Rietspruit include drinking of the Rietspruit water, using the water for cooking, bathing in the river, as well as fishing in the dam located downstream of the river (Figure 4 ). The water is also used for the irrigation of farmlands. The commercial wheat plantation located a few kilometres from the mine uses the water from the dam for irrigation (Figure 4 C). Several studies have been done on the uptake of U and other heavy metals by plants (Dzoma, Moralo, Motsei, Ndou, & Bakunzi, 2010 ; Edayilam et al., 2020 ; Genthe, Kapwata, Le Roux, Chamier, & Wright, 2018 ; Gupta & Walther, 2020 ; Hakonson-Hayes, Fresquez, & Whicker, 2002 ). Wind erosion is another pathway. The deposition of tailings materials on nearby farmland could potentially introduce U into the food chain due to the uptake by plants. The consumption of animals that were fed with plants irrigated with polluted water is also another route for indirect consumption of U by humans (Figures 4 A & B). Formal and informal settlers within the immediate environment of the slime dams could also be exposed as a result of inhaling dust particles (Figure 4 F). The only exposure pathway considered in this study is the oral ingestion of U from drinking water. This is the most prevalent exposure pathway experienced in the Rietspruit by different population groups that depend on the water for both domestic and religious activities (Figure 2 E) and the primary objective of this study. Mechanism of transport The major mode of transportation of U from the source pollutant to the Rietspruit is through water and air. Exposed population The majority of the inhabitants around the study area live in informal settlements, e.g. Lawley (Figure 1 ). Informal settlements are housing areas often built illegally on municipal land by people who cannot afford to live in urban areas of the country (Huchzermeyer, 2009 ). Most of the houses in an informal settlement are built out of metal sheets and other materials (Figure 4 F). Other exposed populations are the worshippers using the water from the river for their various religious activities which include drinking. On a visit to site 6, 7, 8, 9 and 11, cooking activities using water from the river was also witnessed as well as bathing in the river. The worshippers are of different age groups and sex. Annual effective dose (radiation dose) due to the ingestion of uranium in Rietspruit water Whenever there is human contact with a hazardous chemical as U in this study, there is exposure (Means, 1989 ). Residents and worshippers using the water for drinking, cooking, bathing are therefore exposed. In order to screen the area that could constitute a health risk, radiation doses for all the sampled sites were calculated and compared with the radiation dose limit prescribed by UNSCEAR (2000) for U 238 in water. Annual effective dose is the estimated value of radiation energy received or absorbed by the human body as a result of an intake of a certain amount of radioactivity in a year (DWAF, 2002 ). In order to calculate the annual effective dose, equation 1 was used. $$\text{A}\text{n}\text{n}\text{u}\text{a}\text{l} \text{e}\text{f}\text{f}\text{e}\text{c}\text{t}\text{i}\text{v}\text{e} \text{d}\text{o}\text{s}\text{e}=\text{C} \times \text{A}\text{W}\text{I} \times \text{D}\text{C}\text{F}\dots \dots \dots \dots \dots \dots .\text{e}\text{q}\text{u}\text{a}\text{t}\text{i}\text{o}\text{n} 1$$ Where C is the activity concentration of U (Bq/l), DCF is the dose conversion factor for a specific age group (Sv/Bq) and AWI is the age-dependent annual water intake. The annual water intake default values for different age groups and the dose conversion factor values were obtained from the Department of Water Affairs handbook (DWAF, 2002 ). The concentration of U recorded in the water was converted to activity concentration using 1 µg/l = 0.025 Bq/l as the conversion factor. Lifetime cancer risk (Carcinogenic risk assessment) The lifetime cancer risk (risk factor) estimates the likelihood of developing cancer due to exposure to a carcinogen (Bleam, 2012 ). In order to calculate the lifetime risk factor due to the consumption of the Rietspruit water, equation 2 was used. The concentrations of U in the Rietspruit water were converted to uranium activity concentration (Bq/l). 1µg/l = 0.025 Bq/l. The calculation is based on the assumption that the activity concentration of U at each site remains constant and the resident consumes the water at the specified rate throughout their lifespan. This method was designed by the US EPA (USEPA, 1986 ) and has been used in several studies (Bleam, 2012 ; Giri & Jha, 2012 ; Okeyode & Jibiri, 2013 ). $$\text{L}\text{i}\text{f}\text{e}\text{t}\text{i}\text{m}\text{e} \text{c}\text{a}\text{n}\text{c}\text{e}\text{r} \text{r}\text{i}\text{s}\text{k}=\text{U} \text{i}\text{n}\text{t}\text{a}\text{k}\text{e} (\text{B}\text{q}/\text{l})\times \text{r}\text{i}\text{s}\text{k} \text{c}\text{o}\text{e}\text{f}\text{f}\text{i}\text{c}\text{i}\text{e}\text{n}\text{t} \dots \dots \dots \dots \dots \text{e}\text{q}\text{u}\text{a}\text{t}\text{i}\text{o}\text{n} 2$$ In order to calculate lifetime cancer risk, the activity intake of U has to be determined using the concentration of dissolved uranium quantified in the water samples collected at each site. Equation 3 was used to calculate the uranium activity intake; $$\text{U}\text{r}\text{a}\text{n}\text{i}\text{u}\text{m} \text{i}\text{n}\text{t}\text{a}\text{k}\text{e} (\text{B}\text{q}/\text{l})=\text{C}\times \text{I}\text{R} \times \text{E}\text{F}\times \text{E}\text{D}\dots \dots \dots \dots \dots \dots \dots \text{e}\text{q}\text{u}\text{a}\text{t}\text{i}\text{o}\text{n} 3$$ Where C is the uranium activity concentration (Bq/l), ED is the lifetime exposure duration (70 years), and EF is the exposure frequency (365 days per year). Lifetime cancer morbidity and mortality risk coefficients for uranium are 1.3E-09 and 1.73E-09 respectively (EPA; Radiation, 2000 ). Hazard quotient (Non-carcinogenic risk assessment) Hazard quotient (HQ) is the ratio of the lifetime average daily dose at each site and the reference dose for U (0.6 µg/kg/day) through the ingestion of drinking water. A reference dose (RfD) is the estimate of the dose level considered safe for human consumption (ATSDR, 2014 ). It relates the dose at the exposure point to a toxicological endpoint (Bleam, 2012 ). Hazard quotient below 1 signifies no risk while above 1 means there is sufficient risk. Hazard quotient has been used to assess the health risk of U in some studies (Giri & Jha, 2012 ; C Kamunda, Mathuthu, & Madhuku, 2018 ; Njinga, Tshivhase, & Mathuthu, 2016 ). $$\text{H}\text{a}\text{z}\text{a}\text{r}\text{d} \text{q}\text{u}\text{o}\text{t}\text{i}\text{e}\text{n}\text{t}= \frac{\text{l}\text{i}\text{f}\text{e}\text{t}\text{i}\text{m}\text{e} \text{a}\text{v}\text{e}\text{r}\text{a}\text{g}\text{e} \text{d}\text{a}\text{i}\text{l}\text{y} \text{d}\text{o}\text{s}\text{e}}{\text{r}\text{e}\text{f}\text{e}\text{r}\text{e}\text{n}\text{c}\text{e} \text{d}\text{o}\text{s}\text{e}}\dots \dots \dots \dots \dots \dots \dots \dots \text{e}\text{q}\text{u}\text{a}\text{t}\text{i}\text{o}\text{n} 4$$ Results And Discussion Concentration of U in collected water samples The highest concentration of U (781.9 µg/l) in the water was recorded at the inflow of PW dam (Rietspruit headwater) (Table 1 ). The concentration of U decreases gradually with distance from the mine. This is similar to the study of Davidson ( 2003 ) which also reported a gradual reduction in the concentration of U moving downstream from the source pollutant. The concentration of U in the water is above WHO guideline limit in drinking water (30 µg/l) and South Africa standards (10 µg/l in water used for irrigation and 30 µg/l in drinking water) for about 24km away from the source pollutant. The concentration of U in the water used for the irrigation of the wheat plantation (Figure 4 C) is 52.7 µg/l. Hakonson-Hayes et al ( 2002 ), concluded that the concentration of U in plants is directly proportional to the concentration of U in the water used for the irrigation of the plant. The consumption of such plants by humans and animals that fed on the plant could be detrimental to human health (ATSDR, 2014 ; Bjørklund et al., 2020 ; Corlin et al., 2016 ). Table 1 Concentration of uranium in the stream (28th August 2020) Site number Site name Field number Distance from PW dam (km) U water (µg/l) Site 1 PW dam inlet 1 0 781.9 Site 2 Channel water *1 0 52.7 Site 2 Corner of dam *2 0 55.8 Site 3 PW dam outflow 2 1 181.2 Site 4 Wetland 1 3 2 101.4 Site 5 Wetland 2 inflow *8 3 62.0 Site 5 Wetland middle *7 3 63.4 Site 5 Wetland outflow *6 4 65.6 Site 6 Damlit outflow 4 6 49.2 Site7 Between damlit 5 6 104.9 Site8 Religious site 5B 8 103.3 Site9 Post religious site 6 8 103.8 Site10 Post bridge 7 12 70.2 Site11 Poortjie 8 14 74.5 Site12 Pre Evaton 9 24 71.1 Site13 Evaton Rietspruit 10 NA 0.3 Site14 Post confluence 11 32 4.9 Site15 Pre confluence Rietspruit & Leeuspruit 13 37 6.0 Site16 Leeuspruit 12 NA 17.4 Site17 Post confluence Rietspruit & Leeuspruit 14 39 6.2 Site18 Post confluence Rietspruit & Leeuspruit 15 43 6.9 Site19 Rietspruit (Potch rd) 16 49 5.1 Site20 Pre-confluence Rietspruit & Klein-rietspruit 18 53 3.7 Site21 Klein-rietspruit 17 NA 0.7 Site22 Post-confluence Rietspruit & Klein-rietspruit 22 55 5.5 Site23 Lochvaal inflow 19 56 6.5 Site24 Lochvaal 20 60 6.9 Site25 Post confluence Rietspruit & Vaal river 21 63 3.0 Maximum 781.9 Average 71.9 Minimum 0.3 SD 146.4 The reduction in the concentration of U from the source pollutant downstream could be attributed to the dilution effect from unpolluted water (e.g discharge from water treatment plants and tributaries), infiltrating groundwater and the river water-sediment interplay. Despite the reduction in the concentration of U in water downstream, the site used for religious activities have U concentration more than twice the guideline limit of U in water. This is about 6 km from the source of the pollutant. The concentrations of U at the sites designated as this study natural background concentration of U were 0.3 µg/l at the Evaton Rietspruit and 0.7 µg/l at the Klein-Rietspruit. As mentioned earlier, these sites were selected as the natural background concentration of U because there is no mining activity or industrial operation upstream of the river. At the Leeuspruit tributary, the concentration of U in the river was 17.4 µg/l. A gold mine is located about 24 km upstream of the sampled site (Figure 1 ). Besides the grazing of cattle and the location of farmlands along the Leeuspruit, no human exposure was witnessed. The source of the water used for irrigation of the farmlands is unknown. However, Leeuspruit water might be used by the residents of the informal settlements within this area. Annual effective dose due to the ingestion of uranium in Rietspruit water There are many human exposure pathways for U, however, the major pathway witnessed during the field survey was considered in this study, ingestion through drinking of water. From Figure 5 , it was confirmed that an individual annual radiation dose limit of 0.1 mSv/year (for members of the general public) prescribed by UNSCEAR (2000) was exceeded at the PW dam inlet for all the age groups. At PW dam outflow, the radiation dose limit was exceeded by the 15 years’ age group while the rest of the age groups’ annual effective dose was equal to the radiation dose limit (0.1 mSv/year). This means the ingestion of the water at the observed U activity concentration will cause a proportional increase in the chance of a health effect. Given the numerous exposure pathways that may cause radiation exposure, it was recommended by the International Commission on Radiological Protection (ICRP) to keep individual exposure doses to a minimum. This is essential in order to keep the total dose received by an individual below the annual dose limit. At sites where human exposure was observed, the annual effective dose was equal to 0.1 mSv/year for all the age groups (site 6 to site 9). The maximum effective dose was recorded at the PW dam inlet for all the age groups (Table3). This coincided with the maximum concentration of U recorded in this study. The annual effective dose is in the order 15 years’ age group as the highest > adults > 1 year > infants > 5 years and 10 years. In Table 2 below, the values of annual water intake (AWI) and dose conversion factor, (DCF) used to calculate the annual effective dose were given. Also included in Table 2 are the minimum, maximum, average and standard deviation for each of the studied age groups. Table 2 Statistics of age-dependent annual effective dose due to the intake of uranium through the ingestion of drinking water Age group (years) AWI (L/year) DCF (Bq/Sv) minimum Maximum Average Standard deviation mSv/year 0 - 12 months 200 1,40E-07 2,00E-04 0,55 0,05 0,1 1 - 4 260 1,20E-07 2,00E-04 0,61 0,06 0,11 5 - 9 300 8,00E-08 2,00E-04 0,47 0,04 0,09 10 -14 350 6,80E-08 2,00E-04 0,47 0,04 0,09 15 - 17 600 6,70E-08 3,00E-04 0,79 0,07 0,15 Adults 730 4,50E-08 2,00E-04 0,64 0,06 0,012 Lifetime cancer risk (Carcinogenic risk assessment) According to US EPA, 1991, lifetime cancer risk ranging from 1.0E-06 to 1.0E-04 is acceptable and above 1.0E-04 require immediate remediation while a cancer risk below 1.0E-06 are not considered to pose any significant health effect (Fryer, Collins, Ferrier, Colvile, & Nieuwenhuijsen, 2006 ; Hu et al., 2012 ). Using equation 2 above, the result of the cancer risk is displayed in table 3 below. The highest mortality cancer risk recorded was 1.1 E-03 and 1.7E -03 for morbidity cancer risk. These values were the only values above the radiological risk limit (1.0E-03) in this study. From the result above, (Figure 6 ), downstream users of the Rietspruit water are below the cancer risk limit and can be considered safe. Similar to the exposure dose result, the PW dam inlet has the highest cancer risk (Figure 6 ). This means the sites require immediate intervention. However, as mentioned earlier, a high concentration of a pollutant in an environment is harmless until there is human contact. Since no human contact was witnessed in this environment, possible human exposure to U will be the consumption of cattle that graze within this environment (Dzoma et al., 2010 ). Hazard quotient (Non-carcinogenic risk assessment) The lifetime average daily dose (LADD) of U due to the ingestion of Rietspruit water ranged from 0.0 to 22.3 µg/kg/day of uranium with an average of 2.1 µg/kg/day. As mentioned earlier, the HQ was estimated for uranium using a reference dose of 0.6 µg/kg/day as recommended by EPA OGWDW (2000). The result of the non-carcinogenic risk (chemical risk) ranged from 0 to 37,2. The minimum HQ was recorded at sites selected as the natural background concentration of U in the study area. Similar to the U concentration in the Rietspruit, the maximum HQ was recorded at the PW dam inlet. In this study, HQ was above 1 for about 24 km from the mining environment. With human exposure observed within this radius, it means people drinking from the water could be exposed to chemical toxins as a result of ingesting U in the water. Recommendation Due to the high concentration of U found in the study area, the usage of the water for domestic, agricultural and religious activities should be discouraged. This could be achieved by educating the inhabitants of the informal settlements, farmers and worshipers about the health impacts of U and the concentration of U in the water used for these activities. Mining companies in conjunction with relevant government agencies should work together in order to remediate this situation. This will help in reducing human exposure to the U. Limitations Risk assessment is based on the assumption that the concentrations of U will remain constant and people consume only the Rietspruit water at the given quantity per day throughout their lifespan. Individual risk can be influenced by genetic, age, sex, diet, state of health and lifestyle factors, as a result, lifetime cancer risk does not estimate the actual risk for any individual. Conclusion Uranium has been introduced into the Rietspruit as a result of a gold and uranium mining plant established upstream of the stream. Due to different human exposures observed within the environment, water samples covering the entire Rietspruit were taken for analysis using ICP-MS to quantify the concentrations of U in the stream. The results from the laboratory analysis were used to characterise both radiological and chemical health risks of U as an element of concern. The concentration of U in water within 24 km from the source pollutant (gold mine) at all the sampled sitesis higher than WHO and South Africa regulatory limit of U in water (30 µg/l = 0.03 mg/l). The concentrations of U in the Rietspruit water decrease as the distance from the mining site increases. The annual effective dose values due to the consumption of the Rietspruit water are above the safe limit within the mining environment, 0.1 mSv/year. Where human exposure was observed, the annual effective dose values for all the age groups were equal to the safe limit. Due to several exposure pathways that contribute to radiological dose, it can be concluded that the Rietspruit water is not safe for consumption. Radiological (lifetime) cancer risks of mortality and morbidity due to Rietspruit water consumption are above the safe limit of 1.0E3 within the mining environment. The grazing of cattle within this environment and the use of the water for irrigation activity could be an entry point for the introduction of U into the food chain. Also, people observed drinking water at these sites and fetching the water for domestic purposes are at risk of radiological exposure. The chemical toxicity of U 238 in the Rietspruit has values above the standard limit. The HQ is above 1 for about 24 km away from the mining environment. These are sites where human exposure, cattle grazing, and farmland were observed. This study revealed that the probability of carcinogenic risk is low, however, the non-carcinogenic risk may be due to the chemical toxicity of U 238 . References Adams, D. H., Sonne, C., Basu, N., Dietz, R., Nam, D.-H., Leifsson, P. S., & Jensen, A. L. (2010). Mercury contamination in spotted seatrout, Cynoscion nebulosus: An assessment of liver, kidney, blood, and nervous system health. Science of the Total Environment, 408 (23), 5808-5816. doi:https://doi.org/10.1016/j.scitotenv.2010.08.019 Anke, M., Seeber, O., Müller, R., Schäfer, U., & Zerull, J. (2009). Uranium transfer in the food chain from soil to plants, animals and man. Geochemistry, 69 , 75-90. doi:https://doi.org/10.1016/j.chemer.2007.12.001 ATSDR. (2014). Toxicological Profile for Uranium. Agency for Toxic Substances and Disease Registry, Public Health Service, US. Department of Health and Human Services . Bjørklund, G., Semenova, Y., Pivina, L., Dadar, M., Rahman, M. M., Aaseth, J., & Chirumbolo, S. (2020). Uranium in drinking water: a public health threat. Archives of Toxicology, 94 (5), 1551-1560. doi:10.1007/s00204-020-02676-8 Bleam, W. F. (2012). Chapter 10 - Risk Assessment. In W. F. Bleam (Ed.), Soil and Environmental Chemistry (pp. 409-447). Boston: Academic Press. Bleise, A., Danesi, P. R., & Burkart, W. (2003). Properties, use and health effects of depleted uranium (DU): a general overview. Journal of environmental radioactivity, 64 (2-3), 93-112. Coetzee, H., Wade, P., & Winde, F. (2002). Reliance on existing wetlands for pollution control around the Witwatersrand gold/uranium mines of South Africa-Are they sufficient? In Uranium in the aquatic environment (pp. 59-64): Springer. Coetzee, H., Winde, F., & Wade, P. (2006). An Assessment of Sources, Pathways, Mechanisms and Risks of Current and Potential Future Pollution of Water and Sediments in Gold-mining Areas of the Wonderfonteinspruit Catchment: Report to the Water Research Commission : Water Research Comission. Corlin, L., Rock, T., Cordova, J., Woodin, M., Durant, J. L., Gute, D. M., . . . Brugge, D. (2016). Health Effects and Environmental Justice Concerns of Exposure to Uranium in Drinking Water. Current Environmental Health Reports, 3 (4), 434-442. doi:10.1007/s40572-016-0114-z Davidson, C. (2003). Catchment diagnostic framework for the Klip River catchment, Vaal Barrage, October 1998-September 1999. University of the Witwatersrand, Johannesburg, Dewar, D. (2019). Uranium mining: environmental and human health effects. In Nuclear non-proliferation in international law-volume IV (pp. 229-235): Springer. Durand, J. F. (2012). The impact of gold mining on the Witwatersrand on the rivers and karst system of Gauteng and North West Province, South Africa. Journal of African Earth Sciences, 68 , 24-43. doi:https://doi.org/10.1016/j.jafrearsci.2012.03.013 DWAF. (2002). Department of Water Affairs and Forestry (DWAF), 2002. Radiological dose calculation and water quality evaluation guideline for domestic water user. Department of Water Affairs and Forestry guideline document, March 2002, Pretoria. Dzoma, B., Moralo, R., Motsei, L., Ndou, R., & Bakunzi, F. (2010). Preliminary findings on the levels of five heavy metals in water, sediments, grass and various specimens from cattle grazing and watering in potentially heavy metal polluted areas of the North West Province of South Africa. J. Anim. Vet. Adv, 9 (24), 3026-3033. Edayilam, N., Ferguson, B., Montgomery, D., Al Mamun, A., Martinez, N., Powell, B. A., & Tharayil, N. (2020). Dissolution and vertical transport of uranium from stable mineral forms by plants as influenced by the Co-occurrence of uranium with phosphorus. Environmental science & technology, 54 (11), 6602-6609. EPA, U. Environmental Protection Agency (1999), Cancer Risk Coefficients for Environmental Exposure to Radionuclides, Federal Guidance Report N. º 13 . Retrieved from EPA, U. (1992). Guidelines for exposure assessment. Federal Register, 57 (104), 22888-22938. Fashola, M. O., Ngole-Jeme, V. M., & Babalola, O. O. (2016). Heavy Metal Pollution from Gold Mines: Environmental Effects and Bacterial Strategies for Resistance. International Journal of Environmental Research and Public Health, 13 (11), 1047. Retrieved from https://www.mdpi.com/1660-4601/13/11/1047 Fedderke, J., & Pirouz, F. (2002). The role of mining in the South African economy. South African Journal of Economic and Management Sciences, 5 (1). Ford, M. (1993). Uranium in South Africa. Journal of the Southern African Institute of Mining and Metallurgy, 93 (2), 37-58. Fryer, M., Collins, C. D., Ferrier, H., Colvile, R. N., & Nieuwenhuijsen, M. J. (2006). Human exposure modelling for chemical risk assessment: a review of current approaches and research and policy implications. Environmental science & policy, 9 (3), 261-274. Genthe, B., Kapwata, T., Le Roux, W., Chamier, J., & Wright, C. Y. (2018). The reach of human health risks associated with metals/metalloids in water and vegetables along a contaminated river catchment: South Africa and Mozambique. Chemosphere, 199 , 1-9. Giri, S., & Jha, V. (2012). Risk assessment (chemical and radiological) due to intake of uranium through the ingestion of drinking water around two proposed uranium mining areas, Jharkhand, India. Radioprotection, 47 (4), 543-551. Gupta, D. K., & Walther, C. (2020). Uranium in Plants and the Environment : Springer. Hakonson-Hayes, A. C., Fresquez, P., & Whicker, F. (2002). Assessing potential risks from exposure to natural uranium in well water. Journal of environmental radioactivity, 59 (1), 29-40. Hu, X., Zhang, Y., Ding, Z., Wang, T., Lian, H., Sun, Y., & Wu, J. (2012). Bioaccessibility and health risk of arsenic and heavy metals (Cd, Co, Cr, Cu, Ni, Pb, Zn and Mn) in TSP and PM2. 5 in Nanjing, China. Atmospheric environment, 57 , 146-152. Huchzermeyer, M. (2009). The struggle for in situ upgrading of informal settlements: a reflection on cases in Gauteng. Development Southern Africa, 26 (1), 59-73. doi:10.1080/03768350802640099 Kamunda, C., Mathuthu, M., & Madhuku, M. (2016). Health Risk Assessment of Heavy Metals in Soils from Witwatersrand Gold Mining Basin, South Africa. International Journal of Environmental Research and Public Health, 13 (7). doi:10.3390/ijerph13070663 Kamunda, C., Mathuthu, M., & Madhuku, M. (2018). Potential human risk of dissolved heavy metals in gold mine waters of Gauteng Province, South Africa. Journal of Toxicology and Environmental Health Sciences, 10 (6), 56-63. Keith, S., Faroon, O., Roney, N., Scinicariello, F., Wilbur, S., Ingerman, L., . . . Diamond, G. (2013). Toxicological Profile for Uranium : Agency for Toxic Substances and Disease Registry (US), Atlanta (GA). Krige, D. (1966). A study of gold and uranium distribution patterns in the Klerksdorp gold field. Geoexploration, 4 (1), 43-53. Kritzinger, A. (2017). SOCIO-ECONOMIC IMPACT ASSESSMENT OF THE PROPOSED CESSATION OF PUMPING AND ASSOCIATED CLOSURE OF THE UNDERGROUND WORKINGS OF THE EZULWINI OPERATIONS OF SIBANYE GOLD, GAUTENG PROVINCE. Report prepared for Sibanye Gold . McCarthy, T. S. (2011). The impact of acid mine drainage in South Africa. South African Journal of Science, 107 (5-6), 01-07. Means, B. (1989). Risk-assessment guidance for superfund. Volume 1. Human health evaluation manual. Part A. Interim report (Final) . Retrieved from Njinga, R. L., Tshivhase, V. M., & Mathuthu, M. (2016). Chemical toxicity of surface-based drinking water sources due to natural uranium pollutant around princess gold mine environs in Roodepoort, South Africa. Exposure and Health, 8 (4), 457-464. NRC. (2009). Science and decisions: advancing risk assessment. Okeyode, I., & Jibiri, N. (2013). Excess lifetime cancer risks associated with the use of sediments from Ogun River, Nigeria as building material. Research Journal of Physics, 7 (1), 1-8. Phillips, G. N., & Law, J. D. (2000). Witwatersrand gold fields: geology, genesis and exploration. Reviews in Economic Geology, 13 , 439-500. Radiation, U. N. S. C. o. t. E. o. A. (2000). Sources and Effects of Ionizing Radiation (New York: United Nations). In: Sales Publications. Raji, I. B., Hoffmann, E., Ngie, A., & Winde, F. (2021). Assessing Uranium Pollution Levels in the Rietspruit River, Far West Rand Goldfield, South Africa. International Journal of Environmental Research and Public Health, 18 (16), 8466. Ross, J.-H., & Dudel, E. G. (2008). Uranium loads and accumulation in a mine water contaminated wetland. Mine water and the environment , 225-228. Schöner, A., Noubactep, C., Büchel, G., & Sauter, M. (2009). Geochemistry of natural wetlands in former uranium milling sites (eastern Germany) and implications for uranium retention. Geochemistry, 69 , 91-107. doi:https://doi.org/10.1016/j.chemer.2007.12.003 Tutu, H., Cukrowska, E., McCarthy, T., Mphephu, N., & Hart, R. (2003). Determination and modelling of geochemical speciation of uranium in gold mine polluted land in South Africa. Paper presented at the D. Armstrong, AB de Villiers, RLP Kleinmann, TS McCarthy & PJ Norton, Mine water and the environment. Proceedings of the 8th International Mine Water Association Congress, Johannesburg, South Africa. Tutu, H., McCarthy, T., & Cukrowska, E. (2008). The chemical characteristics of acid mine drainage with particular reference to sources, distribution and remediation: the Witwatersrand Basin, South Africa as a case study. Applied geochemistry, 23 (12), 3666-3684. USEPA. (1986). Guidelines for carcinogen risk assessment. Federal Register, 51 (185), 33992-34003. WHO. (2001). Depleted uranium: sources, exposure and health effects World Health Organization, No. WHO/SDE/PHE/01.1 . Winde, F. (2001). Slimes dams as source of uranium contamination of streams–the Koekemoer Spruit (Klerksdorp gold field) as a case study. Paper presented at the Conference on environmentally responsible mining in Southern Africa. Winde, F. (2004). Inventory of uranium sources and pathways in the catchment. In: Coetzee, H (compiler): An assessment of sources, pathways, mechanisms and risks of current and potential future pollution of water and sediments in gold-mining areas of the Wonderfonteinspruit catchment . Retrieved from Water Research Commission Report No 1214/1/06: Winde, F. (2011). Challenges in assessing uranium-related health risks: Two case studies for the aquatic exposure pathway from South Africa–Part I: Guideline and toxicity issues and the Pofadder case study. In The New Uranium Mining Boom (pp. 529-538): Springer. Winde, F., & de Villiers, A. B. (2002). The nature and extent of uranium contamination from tailings dams in the Witwatersrand gold mining area (South Africa). In Uranium in the aquatic environment (pp. 889-898): Springer. Winde, F., & Sandham, L. (2004). Uranium pollution of South African streams–An overview of the situation in gold mining areas of the Witwatersrand. GeoJournal, 61 (2), 131-149. Winde, F., & van der Walt, I. J. (2004). The significance of groundwater-stream interactions and fluctuating stream chemistry on waterborne uranium contamination of streams - a case study from a gold mining site in South Africa. Journal of Hydrology, 287 (1-4), 178-196. doi:10.1016/j.jhydrol.2003.10.004 Winde, F., Wade, P., & van der Walt, I. J. (2004). Gold tailings as a source of waterborne uranium contamination of streams - The Koekemoerspruit(#) (Klerksdorp goldfield, South Africa) as a case study - Part I of III: Uranium migration along the aqueous pathway. Water Sa, 30 (2), 219-225. Retrieved from ://WOS:000222001100010 WWF-SA. (2016). Water: Facts and Futures-Rethinking South Africa's Water Future. In: WWF-SA Cape Town. Zamora, M. L., Tracy, B. L., Zielinski, J. M., Meyerhof, D. P., & Moss, M. A. (1998). Chronic ingestion of uranium in drinking water: a study of kidney bioeffects in humans. Toxicol Sci, 43 (1), 68-77. doi:10.1006/toxs.1998.2426 Tables Table 3 is not available with this version Cite Share Download PDF Status: Posted Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-1177732","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":71225267,"identity":"6aa05dde-ca96-4838-9b0e-d0672d8c118c","order_by":0,"name":"Iyioluwa Busuyi Raji","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYHCChAMJDBIMfCDmByBmYydWCxuQxTgDpIWZWLtAWph5QCxCWszbDzw88LDNQo5NIsfws82vbfJ8zAyMHz7m4NYicyYh4UBim4QxUIuxdG7fbcM2ZgZmyZnbcGuRYIBoAaLcDdK5PbcZgVrYmHnxaeF/ANey+bdlz217wlokELZsk2b4cTuRCC1AWxLOAf3C8/6bZW/D7eQ2ZsZm/H7hz0n++KOsTo6fPS35xo8/t23ntzcf/PARjxYGBp4EBkY2KJuxDUw24FMPBOwHGBj+wDh/8CgcBaNgFIyCEQsAYEVOxgrolpkAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-7110-3715","institution":"North-West University Potchefstroom Campus: North-West University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Iyioluwa","middleName":"Busuyi","lastName":"Raji","suffix":""},{"id":71225268,"identity":"27137228-7d4f-4e0a-8c16-b1faa328baf7","order_by":1,"name":"Emile Hoffmann","email":"","orcid":"","institution":"North-West University Potchefstroom Campus: North-West University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Emile","middleName":"","lastName":"Hoffmann","suffix":""},{"id":71225269,"identity":"7cc45877-d41e-4ef7-83cd-6fc411e892f5","order_by":2,"name":"Ewald Erasmus","email":"","orcid":"","institution":"North-West University Potchefstroom Campus: North-West University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ewald","middleName":"","lastName":"Erasmus","suffix":""},{"id":71225270,"identity":"b4f44b33-6ca7-4912-ad4b-e6b940a53848","order_by":3,"name":"Adeline Ngie","email":"","orcid":"","institution":"North-West University Potchefstroom Campus: North-West University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Adeline","middleName":"","lastName":"Ngie","suffix":""},{"id":71225271,"identity":"d57734fc-2379-4057-8bc2-5e82b1884989","order_by":4,"name":"Frank Winde","email":"","orcid":"","institution":"North-West University Potchefstroom Campus: North-West University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Frank","middleName":"","lastName":"Winde","suffix":""}],"badges":[],"createdAt":"2021-12-16 13:32:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1177732/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1177732/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":16689563,"identity":"3353da11-93fc-4257-8b81-7c399f9cf345","added_by":"auto","created_at":"2021-12-22 15:38:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":261594,"visible":true,"origin":"","legend":"\u003cp\u003eGeological map of the study area.\u003c/p\u003e","description":"","filename":"fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/44fc4ec98f7c40583f37fcac.png"},{"id":16689564,"identity":"efa0f99e-f2db-4a05-935c-7a7d453eaf90","added_by":"auto","created_at":"2021-12-22 15:38:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1405616,"visible":true,"origin":"","legend":"\u003cp\u003eStudy area catchment showing the sampled sites\u003c/p\u003e","description":"","filename":"fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/19a04d39c58de6c8a3a3b5a9.png"},{"id":16689565,"identity":"420aa9f4-9530-4d05-9990-80616175ad0f","added_by":"auto","created_at":"2021-12-22 15:38:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1323549,"visible":true,"origin":"","legend":"\u003cp\u003eGoogle Earth image showing the mining site\u003c/p\u003e","description":"","filename":"fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/38db1703d9617093ea8d75f6.png"},{"id":16689566,"identity":"cb3356be-1c77-46fb-b557-efdb262b95af","added_by":"auto","created_at":"2021-12-22 15:38:21","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1326885,"visible":true,"origin":"","legend":"\u003cp\u003eExposure pathways witnessed in Rietspruit; A: Cattle grazing in the Rietspruit river B: Cattle grazing next to the canal used by the mine to discharge water C: Wheat plantation irrigated by water from PW dam, D: Local residents fishing in PW dam, E: Religious site, F: Informal settlement within the study area.\u003c/p\u003e","description":"","filename":"fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/5a755663e6cba144510154d1.png"},{"id":16689567,"identity":"9b30a132-fe03-4e3e-b830-9c39a51622ba","added_by":"auto","created_at":"2021-12-22 15:38:22","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":49862,"visible":true,"origin":"","legend":"\u003cp\u003e\tAnnual effective dose for different age groups: via drinking untreated stream water only at site-specific U - concentrations observed on 28th August 2020\u003c/p\u003e","description":"","filename":"fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/d01857b41d565d8c7a61da5a.png"},{"id":16689568,"identity":"11fb5555-4df0-4455-8424-87acbeae3688","added_by":"auto","created_at":"2021-12-22 15:38:22","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":52018,"visible":true,"origin":"","legend":"\u003cp\u003eMortality and morbidity cancer risk: via drinking untreated stream water only at site-specific U - concentrations observed on 28th August 2020\u003c/p\u003e","description":"","filename":"fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/47d65a019da2d7d0837c3bc2.png"},{"id":16689570,"identity":"2f68ec42-464c-460d-8c38-1887631b3e25","added_by":"auto","created_at":"2021-12-22 15:38:22","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":45496,"visible":true,"origin":"","legend":"\u003cp\u003eNon-carcinogenic risk: via drinking untreated stream water only at site-specific U - concentrations observed on 28th August 2020\u003c/p\u003e","description":"","filename":"fig7.png","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/bf4b62958dc33ddc3727e574.png"},{"id":16976581,"identity":"1e7889e7-e548-4aaf-b934-5de709eec53f","added_by":"auto","created_at":"2022-01-04 13:28:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4407560,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1177732/v1/55ee9e5b-cbe2-408c-b30d-a43edf5bbacc.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eAssessing Health Risk Associated with Uranium in Rietspruit Water, Far West Rand Goldfield, South Africa\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe quality of most South African water has deteriorated over the years which poses serious health risks to humans and livestock (WWF-SA, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The main source of South Africa water input is rainfall, however, with annual average rainfall below 50% of world average rainfall, the country is regarded as a water-scarce country. Despite the scarcity, 62% of South Africa\u0026rsquo;s water is used for irrigation, 11% is used for mining and industrial use (WWF-SA, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; DWAS, 2020). Poor communities like residents of informal settlements have the extreme problem of insufficient water services and consequent water-related ailments. This is because they depend on nearby surface water to meet their water needs. In gold mining areas, most of the surface water was polluted with heavy metals, uranium inclusive.\u003c/p\u003e \u003cp\u003eUranium, U, has been reported to have health impacts on humans exposed to the element (Adams et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; ATSDR, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Bj\u0026oslash;rklund et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Bleise, Danesi, \u0026amp; Burkart, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Winde, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Zamora, Tracy, Zielinski, Meyerhof, \u0026amp; Moss, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). Depending on the solubility of the uranium compound, exposure route, and concentration, kidneys, lungs, bones are among the targeted vitals that could be damaged by U (ATSDR, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Dewar, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Keith et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; WHO, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Uranium is mined in South Africa in most cases as the by-product of gold mining (Ford, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Krige, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e1966\u003c/span\u003e; Tutu, Cukrowska, McCarthy, Mphephu, \u0026amp; Hart, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Winde \u0026amp; de Villiers, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). High concentrations of U have been found within gold mines in water and sediment (Durand, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Fashola, Ngole-Jeme, \u0026amp; Babalola, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Caspah Kamunda, Mathuthu, \u0026amp; Madhuku, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Raji, Hoffmann, Ngie, \u0026amp; Winde, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGold mining has been a contributing factor to the economy of South Africa, however, large volumes of mine wastes have been deposited as a result (Fedderke \u0026amp; Pirouz, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; McCarthy, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). In the Witwatersrand Basin, one of the richest gold deposits worldwide (Tutu, McCarthy, \u0026amp; Cukrowska, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), high concentrations of U have been recorded in some of the mined gold reefs. About 70 years ago, the Far West Rand became the first goldfield in South Africa where commercial production of U was established (Coetzee, Winde, \u0026amp; Wade, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Winde (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2001\u003c/span\u003e) reported an average U concentration of about 110 mg/kg in gold tailings across seven goldfields of the Witwatersrand Basin. Winde (\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) concluded that for each ton of gold produced, more than 10 tons of U were brought to the earth\u0026rsquo;s surface. Mined gold reefs are therefore regarded as the primary source of U (Winde \u0026amp; Sandham, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2004\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOther sources of U pollution include mine waste deposits such as slime dams and mine dumps often located close to streams or rivers. In many cases, these waste deposits are the primary source of U pollution of the nearby water bodies. The process includes the transport of dissolved U via seepage into underlying alluvial aquifers (Winde \u0026amp; van der Walt, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) and of U-bearing tailings particles by wind and water erosion (Winde \u0026amp; Sandham, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Uranium can be emitted from point sources or from non-point (diffuse) sources. Point source pollution includes the discharge of fissure and processed water through canals and pipelines into nearby streams or dams as witnessed in this study. Despite the fact that the mine has been decommissioned about 5 years ago, dewatering of underground shafts is still ongoing. Another example of point source pollution is the storm-water run-off from contaminated mining environments such as slime dams, retention dams, rock and sand dumps. A typical example of diffuse sources of pollution includes seepage from slime dams, run-off from mine dumps.\u003c/p\u003e \u003cp\u003eUranium is released into the environment in a number of ways which include erosion of slime dams by wind and water leading to eroded slimes settling on dams, wetland, irrigation channels and agricultural land etc. (Coetzee et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). In addition, there are spillages of tailings associated with burst pipelines, partial dam failures etc.\u003c/p\u003e \u003cp\u003eHigh concentrations of U have been found several kilometres from the mining site in river sediment, wetlands and dams as a result of precipitation, adsorption, co-precipitation and bioaccumulation (Winde, Wade, \u0026amp; van der Walt, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Wetlands and dams have been identified as sinks for U and other toxic heavy metals such as mercury, lead, cadmium, arsenic (Coetzee, Wade, \u0026amp; Winde, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Ross \u0026amp; Dudel, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Sch\u0026ouml;ner, Noubactep, B\u0026uuml;chel, \u0026amp; Sauter, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Raji et al., (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) recorded high concentrations of the aforementioned heavy metals above the acceptable limit in a wetland and dam located about 3 km and 6 km respectively away from a mining site. These sites can be a secondary source of U pollution and other heavy metals if there is a change in the water chemistry which could be influenced by the water\u0026rsquo;s pH, electric conductivity, redox state and seasonal changes (from winter to summer).\u003c/p\u003e \u003cp\u003eThe focus of this study is on the Rietspruit, a small stream draining the south-eastern part of the Far West Rand (FWR) goldfield that is impacted by mining-related water pollution. The study explores the main pathways of U entering the Rietspruit system including the leaching of U from mine wastes, aqueous transport of dissolved uranium from on-site sources and mechanisms governing the transport of dissolved U within the fluvial system which include immobilisation and remobilisation to and from fluvial sediments, respectively.\u003c/p\u003e \u003cp\u003eUranium is released from mine waste during a rain event and transported to Peter Wright dam (Rietspruit headwater). A concentration of about 52.7 \u0026micro;g/l of U was recorded in the fissure water discharged by the mine into the PW dam. (Raji et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). According to Kritzinger (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), about 68 Ml of fissure water is pumped into the PW dam per day, this means the amount of U discharged into the PW dam is about 52 700 mg/l of U per day. Thus, the discharge of fissure water into the PW dam is the most significant U source into the Rietspruit. The outflow from the PW dam into the Rietspruit makes the Rietspruit a perennial one. Observations during field sampling indicated that the Rietspruit water is used for drinking, cooking, bathing (especially by the residents of informal settlements within the area and religious worshippers) and animal watering and dam water is used for irrigation of farmland. Plant\u0026rsquo;s uptake of U from the soil could be a result of air pollution from slime dams and water used to irrigate such plants (Anke, Seeber, M\u0026uuml;ller, Sch\u0026auml;fer, \u0026amp; Zerull, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Gupta \u0026amp; Walther, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDue to human exposure witnessed during fieldwork, and the lack of information on the level of U these people could be exposed to, it is imperative to assess potential health risks associated with the concentration of U found in the Rietspruit. This study will be used to sensitize the locals about the danger involved with the use of the water for domestic, agricultural and religious purposes. Since the most regular human exposure pathway witnessed was the ingestion of the water from the stream, both carcinogenic and non-carcinogenic risk assessments were carried out.\u003c/p\u003e \u003cp\u003eThe objectives of this study are;\u003c/p\u003e \u003cp\u003e1) To determine the concentration of U in the Rietspruit water.\u003c/p\u003e \u003cp\u003e2) To assess the health risk posed by U level in the Rietspruit water.\u003c/p\u003e \u003cp\u003e3) Propose general recommendations.\u003c/p\u003e"},{"header":"Material And Method","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy area\u003c/h2\u003e \u003cp\u003eThe Rietspruit is located in Gauteng Province, South Africa about 1 km away from a gold and uranium mine. The gold and uranium mine (coordinate: 26\u0026deg;21'46\"S 27\u0026deg;42'52\"E) was operational for about 56 years before it was decommissioned in August 2016 discharge their fissure and process water into the Peter Wright dam (PW dam). The outflow from the PW dam is the source of the Rietspruit. It is believed that the Rietspruit will be a non-perennial river if the mine should stop discharging water into the PW dam.\u003c/p\u003e \u003cp\u003eThe river flows for about 60 km southwardly before joining the Vaal river (Figure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The associated drainage region name is C22H according to the Department of Water Affairs and Sanitation (Figure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) comprising a catchment area of about 454 km\u003csup\u003e2\u003c/sup\u003e. Contributing tributaries include the Leeuspruit, Evaton Rietspruit and Klein-Rietspruit. While Leeuspruit is also polluted with U as a result of a gold mine located upstream of the confluence with Rietspruit, the Evaton Rietspruit and Klein-Rietspruit are not polluted as they drain areas without mining activity. The Leeuspruit is located in the C22J Quaternary Catchment (Figure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) draining some 668.7 km\u003csup\u003e2\u003c/sup\u003e (Department of Water Affairs and Sanitation, 2011). As a result of the absence of mining or industrial activities upstream of both the Evaton Rietspruit and Klein-Rietspruit, the concentration of U in the water of these streams was used as the natural background concentration of U. Farms are located within the area and most of them depend on the water from the Rietspruit for irrigation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe climate of the study area is temperate, defined by moderately cold winters (April to August) and hot summers (October to March). Annual rainfall occurs between October to March and with an average of about 664 mm. Evaporation is about twice the annual rainfall (about 1700 mm). In winter, the average temperature is 13 \u003csup\u003eo\u003c/sup\u003eC and 24 \u003csup\u003eo\u003c/sup\u003eC in summer (Caspah Kamunda et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe Ezulwini gold and uranium mine is located in the Witwatersrand Basin, a sedimentary basin of about 2.7 billion years of age containing a stratigraphic sequence about 6 km thick made of quartzites, conglomerates and lava (Phillips \u0026amp; Law, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). Underlying the mine, gold is found in the upper Elsburg in the form of native gold and is associated with sulphide minerals (e.g pyrite). Also, gold is found in the middle Elsburg reefs associated with pyrite underlying the mine and U is mined in the middle Elsburg reef (Kritzinger, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) and it is found in the form of uraninite.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eField work\u003c/h2\u003e \u003cp\u003eA total of 28 water samples were collected on the 28th of August 2020 across the entire length of the Rietspruit (Figure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Water samples were collected in a 100 ml water bottle below the water surface. The water bottle was rinsed three times with the river water and decanted away from the sampled site. Water samples were taken in the middle of the river, depending on the depth of the site, to avoid sampling the banks of the river. Each water bottle was labelled accordingly and kept in a cooler box. The samples were all taken to the laboratory the following day for chemical analysis. Samples were analysed in the laboratory to determine the concentration of U using inductively coupled plasma mass spectrometry (ICP-MS).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eLab analysis\u003c/h2\u003e \u003cp\u003eThe chemical analysis of the water samples was done at the Eco-analytical laboratory in North-West University, Potchefstroom Campus, South Africa. Each water sample was first filtered using a 0.45 \u0026micro;m pre-nylon sieve to remove suspended particles. 1 mL of the filtered water was measured and 9 mL of nitric acid was added to remove any dissolved organic material in the water. An Agilent 7500 CE ICP-MS with Collision Reaction Cell (CRC) technology for interference removal was used to determine the concentration of U in the water. In order to achieve a quantitative result, the instrument is calibrated using ULTRASPEC certified custom mixed multi-element stock standard (De Bruyn Spectroscopic Solutions, Midrand, South Africa) solutions containing all the elements of interest.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eExposure assessment\u003c/h2\u003e \u003cp\u003eAccording to the US EPA (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e1992\u003c/span\u003e), exposure assessment can be defined as the determination of the magnitude, frequency and duration of exposure and exposure dose. Exposure assessment includes identification of all important sources of pollutant, routes of exposure (exposure pathways), potentially exposed population, mechanism of pollutant transportation, quantification of exposure, toxicity assessment of pollutant, and risk characterisation. Exposure assessment is one of the most essential steps in human health risk assessment, hazard identification, dose-response assessment and risk characterization are the other steps (NRC, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSource of uranium pollution\u003c/strong\u003e \u003cp\u003eThe main source of uranium, as a contaminant of concern, in the Rietspruit is the Ezulwini Gold and Uranium mine (Figure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Slimes and waste rock are deposited on the surface. Oxidised mine wastes release U when in contact with water (in the form of rain, pore-water and seepage), which then runs-off into PW dam inflow. The mine also discharges fissure water with elevated concentration of U into PW dam, Rietspruit headwater. Fissure water is mainly water from underground mine workings that was in contact with oxidised uranium ore (Winde, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Another source of U in the Rietspruit includes the settling of tailings materials transported by wind to surface water.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eExposure pathway\u003c/strong\u003e \u003cp\u003eIn this study, the pathways include the usage of the water for domestic, religious and agricultural purposes. Domestic and religious activities observed in the Rietspruit include drinking of the Rietspruit water, using the water for cooking, bathing in the river, as well as fishing in the dam located downstream of the river (Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The water is also used for the irrigation of farmlands. The commercial wheat plantation located a few kilometres from the mine uses the water from the dam for irrigation (Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC). Several studies have been done on the uptake of U and other heavy metals by plants (Dzoma, Moralo, Motsei, Ndou, \u0026amp; Bakunzi, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Edayilam et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Genthe, Kapwata, Le Roux, Chamier, \u0026amp; Wright, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Gupta \u0026amp; Walther, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Hakonson-Hayes, Fresquez, \u0026amp; Whicker, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2002\u003c/span\u003e).\u003c/p\u003e \u003c/p\u003e \u003cp\u003eWind erosion is another pathway. The deposition of tailings materials on nearby farmland could potentially introduce U into the food chain due to the uptake by plants. The consumption of animals that were fed with plants irrigated with polluted water is also another route for indirect consumption of U by humans (Figures \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA \u0026amp; B). Formal and informal settlers within the immediate environment of the slime dams could also be exposed as a result of inhaling dust particles (Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eF).\u003c/p\u003e \u003cp\u003eThe only exposure pathway considered in this study is the oral ingestion of U from drinking water. This is the most prevalent exposure pathway experienced in the Rietspruit by different population groups that depend on the water for both domestic and religious activities (Figure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE) and the primary objective of this study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eMechanism of transport\u003c/strong\u003e \u003cp\u003eThe major mode of transportation of U from the source pollutant to the Rietspruit is through water and air.\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eExposed population\u003c/h2\u003e \u003cp\u003eThe majority of the inhabitants around the study area live in informal settlements, e.g. Lawley (Figure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Informal settlements are housing areas often built illegally on municipal land by people who cannot afford to live in urban areas of the country (Huchzermeyer, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Most of the houses in an informal settlement are built out of metal sheets and other materials (Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eF).\u003c/p\u003e \u003cp\u003eOther exposed populations are the worshippers using the water from the river for their various religious activities which include drinking. On a visit to site 6, 7, 8, 9 and 11, cooking activities using water from the river was also witnessed as well as bathing in the river. The worshippers are of different age groups and sex.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eAnnual effective dose (radiation dose) due to the ingestion of uranium in Rietspruit water\u003c/h2\u003e \u003cp\u003eWhenever there is human contact with a hazardous chemical as U in this study, there is exposure (Means, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e1989\u003c/span\u003e). Residents and worshippers using the water for drinking, cooking, bathing are therefore exposed. In order to screen the area that could constitute a health risk, radiation doses for all the sampled sites were calculated and compared with the radiation dose limit prescribed by UNSCEAR (2000) for U\u003csup\u003e238\u003c/sup\u003e in water.\u003c/p\u003e \u003cp\u003eAnnual effective dose is the estimated value of radiation energy received or absorbed by the human body as a result of an intake of a certain amount of radioactivity in a year (DWAF, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). In order to calculate the annual effective dose, equation 1 was used.\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\text{A}\\text{n}\\text{n}\\text{u}\\text{a}\\text{l} \\text{e}\\text{f}\\text{f}\\text{e}\\text{c}\\text{t}\\text{i}\\text{v}\\text{e} \\text{d}\\text{o}\\text{s}\\text{e}=\\text{C} \\times \\text{A}\\text{W}\\text{I} \\times \\text{D}\\text{C}\\text{F}\\dots \\dots \\dots \\dots \\dots \\dots .\\text{e}\\text{q}\\text{u}\\text{a}\\text{t}\\text{i}\\text{o}\\text{n} 1$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere C is the activity concentration of U (Bq/l), DCF is the dose conversion factor for a specific age group (Sv/Bq) and AWI is the age-dependent annual water intake. The annual water intake default values for different age groups and the dose conversion factor values were obtained from the Department of Water Affairs handbook (DWAF, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). The concentration of U recorded in the water was converted to activity concentration using 1 \u0026micro;g/l = 0.025 Bq/l as the conversion factor.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eLifetime cancer risk (Carcinogenic risk assessment)\u003c/h2\u003e \u003cp\u003eThe lifetime cancer risk (risk factor) estimates the likelihood of developing cancer due to exposure to a carcinogen (Bleam, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). In order to calculate the lifetime risk factor due to the consumption of the Rietspruit water, equation 2 was used. The concentrations of U in the Rietspruit water were converted to uranium activity concentration (Bq/l). 1\u0026micro;g/l = 0.025 Bq/l.\u003c/p\u003e \u003cp\u003eThe calculation is based on the assumption that the activity concentration of U at each site remains constant and the resident consumes the water at the specified rate throughout their lifespan. This method was designed by the US EPA (USEPA, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1986\u003c/span\u003e) and has been used in several studies (Bleam, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Giri \u0026amp; Jha, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Okeyode \u0026amp; Jibiri, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\text{L}\\text{i}\\text{f}\\text{e}\\text{t}\\text{i}\\text{m}\\text{e} \\text{c}\\text{a}\\text{n}\\text{c}\\text{e}\\text{r} \\text{r}\\text{i}\\text{s}\\text{k}=\\text{U} \\text{i}\\text{n}\\text{t}\\text{a}\\text{k}\\text{e} (\\text{B}\\text{q}/\\text{l})\\times \\text{r}\\text{i}\\text{s}\\text{k} \\text{c}\\text{o}\\text{e}\\text{f}\\text{f}\\text{i}\\text{c}\\text{i}\\text{e}\\text{n}\\text{t} \\dots \\dots \\dots \\dots \\dots \\text{e}\\text{q}\\text{u}\\text{a}\\text{t}\\text{i}\\text{o}\\text{n} 2$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eIn order to calculate lifetime cancer risk, the activity intake of U has to be determined using the concentration of dissolved uranium quantified in the water samples collected at each site. Equation 3 was used to calculate the uranium activity intake;\u003cdiv id=\"Equc\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e\n$$\\text{U}\\text{r}\\text{a}\\text{n}\\text{i}\\text{u}\\text{m} \\text{i}\\text{n}\\text{t}\\text{a}\\text{k}\\text{e} (\\text{B}\\text{q}/\\text{l})=\\text{C}\\times \\text{I}\\text{R} \\times \\text{E}\\text{F}\\times \\text{E}\\text{D}\\dots \\dots \\dots \\dots \\dots \\dots \\dots \\text{e}\\text{q}\\text{u}\\text{a}\\text{t}\\text{i}\\text{o}\\text{n} 3$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere C is the uranium activity concentration (Bq/l), ED is the lifetime exposure duration (70 years), and EF is the exposure frequency (365 days per year). Lifetime cancer morbidity and mortality risk coefficients for uranium are 1.3E-09 and 1.73E-09 respectively (EPA; Radiation, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2000\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eHazard quotient (Non-carcinogenic risk assessment)\u003c/h2\u003e \u003cp\u003eHazard quotient (HQ) is the ratio of the lifetime average daily dose at each site and the reference dose for U (0.6 \u0026micro;g/kg/day) through the ingestion of drinking water. A reference dose (RfD) is the estimate of the dose level considered safe for human consumption (ATSDR, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). It relates the dose at the exposure point to a toxicological endpoint (Bleam, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Hazard quotient below 1 signifies no risk while above 1 means there is sufficient risk. Hazard quotient has been used to assess the health risk of U in some studies (Giri \u0026amp; Jha, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; C Kamunda, Mathuthu, \u0026amp; Madhuku, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Njinga, Tshivhase, \u0026amp; Mathuthu, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003cdiv id=\"Equd\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equd\" name=\"EquationSource\"\u003e\n$$\\text{H}\\text{a}\\text{z}\\text{a}\\text{r}\\text{d} \\text{q}\\text{u}\\text{o}\\text{t}\\text{i}\\text{e}\\text{n}\\text{t}= \\frac{\\text{l}\\text{i}\\text{f}\\text{e}\\text{t}\\text{i}\\text{m}\\text{e} \\text{a}\\text{v}\\text{e}\\text{r}\\text{a}\\text{g}\\text{e} \\text{d}\\text{a}\\text{i}\\text{l}\\text{y} \\text{d}\\text{o}\\text{s}\\text{e}}{\\text{r}\\text{e}\\text{f}\\text{e}\\text{r}\\text{e}\\text{n}\\text{c}\\text{e} \\text{d}\\text{o}\\text{s}\\text{e}}\\dots \\dots \\dots \\dots \\dots \\dots \\dots \\dots \\text{e}\\text{q}\\text{u}\\text{a}\\text{t}\\text{i}\\text{o}\\text{n} 4$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e"},{"header":"Results And Discussion","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eConcentration of U in collected water samples\u003c/h2\u003e \u003cp\u003eThe highest concentration of U (781.9 \u0026micro;g/l) in the water was recorded at the inflow of PW dam (Rietspruit headwater) (Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The concentration of U decreases gradually with distance from the mine. This is similar to the study of Davidson (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2003\u003c/span\u003e) which also reported a gradual reduction in the concentration of U moving downstream from the source pollutant.\u003c/p\u003e \u003cp\u003eThe concentration of U in the water is above WHO guideline limit in drinking water (30 \u0026micro;g/l) and South Africa standards (10 \u0026micro;g/l in water used for irrigation and 30 \u0026micro;g/l in drinking water) for about 24km away from the source pollutant. The concentration of U in the water used for the irrigation of the wheat plantation (Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC) is 52.7 \u0026micro;g/l. Hakonson-Hayes et al (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2002\u003c/span\u003e), concluded that the concentration of U in plants is directly proportional to the concentration of U in the water used for the irrigation of the plant. The consumption of such plants by humans and animals that fed on the plant could be detrimental to human health (ATSDR, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Bj\u0026oslash;rklund et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Corlin et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eConcentration of uranium in the stream (28th August 2020)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite number\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSite name\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eField number\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDistance from PW dam (km)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eU water (\u0026micro;g/l)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePW dam inlet\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e781.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChannel water\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e52.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCorner of dam\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e55.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePW dam outflow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e181.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWetland 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e101.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWetland 2 inflow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e62.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWetland middle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e63.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWetland outflow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e65.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDamlit outflow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e49.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBetween damlit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e104.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eReligious site\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e103.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost religious site\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e103.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost bridge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e70.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePoortjie\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e74.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePre Evaton\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e71.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEvaton Rietspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost confluence\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePre confluence Rietspruit \u0026amp; Leeuspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLeeuspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e17.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost confluence Rietspruit \u0026amp; Leeuspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost confluence Rietspruit \u0026amp; Leeuspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRietspruit (Potch rd)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePre-confluence Rietspruit \u0026amp; Klein-rietspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKlein-rietspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost-confluence Rietspruit \u0026amp; Klein-rietspruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLochvaal inflow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLochvaal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSite25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost confluence Rietspruit \u0026amp; Vaal river\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaximum\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e781.9\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAverage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e71.9\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMinimum\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e146.4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe reduction in the concentration of U from the source pollutant downstream could be attributed to the dilution effect from unpolluted water (e.g discharge from water treatment plants and tributaries), infiltrating groundwater and the river water-sediment interplay. Despite the reduction in the concentration of U in water downstream, the site used for religious activities have U concentration more than twice the guideline limit of U in water. This is about 6 km from the source of the pollutant.\u003c/p\u003e \u003cp\u003eThe concentrations of U at the sites designated as this study natural background concentration of U were 0.3 \u0026micro;g/l at the Evaton Rietspruit and 0.7 \u0026micro;g/l at the Klein-Rietspruit. As mentioned earlier, these sites were selected as the natural background concentration of U because there is no mining activity or industrial operation upstream of the river. At the Leeuspruit tributary, the concentration of U in the river was 17.4 \u0026micro;g/l. A gold mine is located about 24 km upstream of the sampled site (Figure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Besides the grazing of cattle and the location of farmlands along the Leeuspruit, no human exposure was witnessed. The source of the water used for irrigation of the farmlands is unknown. However, Leeuspruit water might be used by the residents of the informal settlements within this area.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eAnnual effective dose due to the ingestion of uranium in Rietspruit water\u003c/h2\u003e \u003cp\u003eThere are many human exposure pathways for U, however, the major pathway witnessed during the field survey was considered in this study, ingestion through drinking of water. From Figure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e, it was confirmed that an individual annual radiation dose limit of 0.1 mSv/year (for members of the general public) prescribed by UNSCEAR (2000) was exceeded at the PW dam inlet for all the age groups. At PW dam outflow, the radiation dose limit was exceeded by the 15 years\u0026rsquo; age group while the rest of the age groups\u0026rsquo; annual effective dose was equal to the radiation dose limit (0.1 mSv/year). This means the ingestion of the water at the observed U activity concentration will cause a proportional increase in the chance of a health effect. Given the numerous exposure pathways that may cause radiation exposure, it was recommended by the International Commission on Radiological Protection (ICRP) to keep individual exposure doses to a minimum. This is essential in order to keep the total dose received by an individual below the annual dose limit.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAt sites where human exposure was observed, the annual effective dose was equal to 0.1 mSv/year for all the age groups (site 6 to site 9). The maximum effective dose was recorded at the PW dam inlet for all the age groups (Table3). This coincided with the maximum concentration of U recorded in this study. The annual effective dose is in the order 15 years\u0026rsquo; age group as the highest \u0026gt; adults \u0026gt; 1 year \u0026gt; infants \u0026gt; 5 years and 10 years.\u003c/p\u003e \u003cp\u003eIn Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e below, the values of annual water intake (AWI) and dose conversion factor, (DCF) used to calculate the annual effective dose were given. Also included in Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e are the minimum, maximum, average and standard deviation for each of the studied age groups.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eStatistics of age-dependent annual effective dose due to the intake of uranium through the ingestion of drinking water\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAge group (years)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAWI (L/year)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDCF (Bq/Sv)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eminimum\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c7\" namest=\"c4\"\u003e \u003cp\u003emSv/year\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0 - 12 months\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1,40E-07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2,00E-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0,55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0,05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0,1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1 - 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e260\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1,20E-07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2,00E-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0,61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0,06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0,11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5 - 9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8,00E-08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2,00E-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0,47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0,04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0,09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10 -14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e350\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6,80E-08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2,00E-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0,47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0,04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0,09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15 - 17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6,70E-08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3,00E-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0,79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0,07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0,15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdults\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e730\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4,50E-08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2,00E-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0,64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0,06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0,012\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eLifetime cancer risk (Carcinogenic risk assessment)\u003c/h2\u003e \u003cp\u003eAccording to US EPA, 1991, lifetime cancer risk ranging from 1.0E-06 to 1.0E-04 is acceptable and above 1.0E-04 require immediate remediation while a cancer risk below 1.0E-06 are not considered to pose any significant health effect (Fryer, Collins, Ferrier, Colvile, \u0026amp; Nieuwenhuijsen, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Hu et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Using equation 2 above, the result of the cancer risk is displayed in table 3 below.\u003c/p\u003e \u003cp\u003eThe highest mortality cancer risk recorded was 1.1 E-03 and 1.7E -03 for morbidity cancer risk. These values were the only values above the radiological risk limit (1.0E-03) in this study. From the result above, (Figure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e), downstream users of the Rietspruit water are below the cancer risk limit and can be considered safe. Similar to the exposure dose result, the PW dam inlet has the highest cancer risk (Figure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). This means the sites require immediate intervention. However, as mentioned earlier, a high concentration of a pollutant in an environment is harmless until there is human contact. Since no human contact was witnessed in this environment, possible human exposure to U will be the consumption of cattle that graze within this environment (Dzoma et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eHazard quotient (Non-carcinogenic risk assessment)\u003c/h2\u003e \u003cp\u003eThe lifetime average daily dose (LADD) of U due to the ingestion of Rietspruit water ranged from 0.0 to 22.3 \u0026micro;g/kg/day of uranium with an average of 2.1 \u0026micro;g/kg/day. As mentioned earlier, the HQ was estimated for uranium using a reference dose of 0.6 \u0026micro;g/kg/day as recommended by EPA OGWDW (2000). The result of the non-carcinogenic risk (chemical risk) ranged from 0 to 37,2. The minimum HQ was recorded at sites selected as the natural background concentration of U in the study area. Similar to the U concentration in the Rietspruit, the maximum HQ was recorded at the PW dam inlet.\u003c/p\u003e \u003cp\u003eIn this study, HQ was above 1 for about 24 km from the mining environment. With human exposure observed within this radius, it means people drinking from the water could be exposed to chemical toxins as a result of ingesting U in the water.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eRecommendation\u003c/h2\u003e \u003cp\u003eDue to the high concentration of U found in the study area, the usage of the water for domestic, agricultural and religious activities should be discouraged. This could be achieved by educating the inhabitants of the informal settlements, farmers and worshipers about the health impacts of U and the concentration of U in the water used for these activities.\u003c/p\u003e \u003cp\u003eMining companies in conjunction with relevant government agencies should work together in order to remediate this situation. This will help in reducing human exposure to the U.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eRisk assessment is based on the assumption that the concentrations of U will remain constant and people consume only the Rietspruit water at the given quantity per day throughout their lifespan. Individual risk can be influenced by genetic, age, sex, diet, state of health and lifestyle factors, as a result, lifetime cancer risk does not estimate the actual risk for any individual.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eUranium has been introduced into the Rietspruit as a result of a gold and uranium mining plant established upstream of the stream. Due to different human exposures observed within the environment, water samples covering the entire Rietspruit were taken for analysis using ICP-MS to quantify the concentrations of U in the stream. The results from the laboratory analysis were used to characterise both radiological and chemical health risks of U as an element of concern.\u003c/p\u003e \u003cp\u003eThe concentration of U in water within 24 km from the source pollutant (gold mine) at all the sampled sitesis higher than WHO and South Africa regulatory limit of U in water (30 \u0026micro;g/l = 0.03 mg/l). The concentrations of U in the Rietspruit water decrease as the distance from the mining site increases.\u003c/p\u003e \u003cp\u003eThe annual effective dose values due to the consumption of the Rietspruit water are above the safe limit within the mining environment, 0.1 mSv/year. Where human exposure was observed, the annual effective dose values for all the age groups were equal to the safe limit. Due to several exposure pathways that contribute to radiological dose, it can be concluded that the Rietspruit water is not safe for consumption.\u003c/p\u003e \u003cp\u003eRadiological (lifetime) cancer risks of mortality and morbidity due to Rietspruit water consumption are above the safe limit of 1.0E3 within the mining environment. The grazing of cattle within this environment and the use of the water for irrigation activity could be an entry point for the introduction of U into the food chain. Also, people observed drinking water at these sites and fetching the water for domestic purposes are at risk of radiological exposure.\u003c/p\u003e \u003cp\u003eThe chemical toxicity of U\u003csup\u003e238\u003c/sup\u003e in the Rietspruit has values above the standard limit. The HQ is above 1 for about 24 km away from the mining environment. These are sites where human exposure, cattle grazing, and farmland were observed. This study revealed that the probability of carcinogenic risk is low, however, the non-carcinogenic risk may be due to the chemical toxicity of U\u003csup\u003e238\u003c/sup\u003e.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAdams, D. H., Sonne, C., Basu, N., Dietz, R., Nam, D.-H., Leifsson, P. S., \u0026amp; Jensen, A. L. (2010). Mercury contamination in spotted seatrout, Cynoscion nebulosus: An assessment of liver, kidney, blood, and nervous system health. \u003cem\u003eScience of the Total Environment, 408\u003c/em\u003e(23), 5808-5816. doi:https://doi.org/10.1016/j.scitotenv.2010.08.019\u003c/li\u003e\n\u003cli\u003eAnke, M., Seeber, O., M\u0026uuml;ller, R., Sch\u0026auml;fer, U., \u0026amp; Zerull, J. (2009). Uranium transfer in the food chain from soil to plants, animals and man. \u003cem\u003eGeochemistry, 69\u003c/em\u003e, 75-90. doi:https://doi.org/10.1016/j.chemer.2007.12.001\u003c/li\u003e\n\u003cli\u003eATSDR. (2014). Toxicological Profile for Uranium. \u003cem\u003eAgency for Toxic Substances and Disease Registry, Public Health Service, US. Department of Health and Human Services\u003c/em\u003e.\u003c/li\u003e\n\u003cli\u003eBj\u0026oslash;rklund, G., Semenova, Y., Pivina, L., Dadar, M., Rahman, M. M., Aaseth, J., \u0026amp; Chirumbolo, S. (2020). Uranium in drinking water: a public health threat. \u003cem\u003eArchives of Toxicology, 94\u003c/em\u003e(5), 1551-1560. doi:10.1007/s00204-020-02676-8\u003c/li\u003e\n\u003cli\u003eBleam, W. F. (2012). Chapter 10 - Risk Assessment. In W. F. Bleam (Ed.), \u003cem\u003eSoil and Environmental Chemistry\u003c/em\u003e (pp. 409-447). Boston: Academic Press.\u003c/li\u003e\n\u003cli\u003eBleise, A., Danesi, P. R., \u0026amp; Burkart, W. (2003). Properties, use and health effects of depleted uranium (DU): a general overview. \u003cem\u003eJournal of environmental radioactivity, 64\u003c/em\u003e(2-3), 93-112.\u003c/li\u003e\n\u003cli\u003eCoetzee, H., Wade, P., \u0026amp; Winde, F. (2002). Reliance on existing wetlands for pollution control around the Witwatersrand gold/uranium mines of South Africa-Are they sufficient? In \u003cem\u003eUranium in the aquatic environment\u003c/em\u003e (pp. 59-64): Springer.\u003c/li\u003e\n\u003cli\u003eCoetzee, H., Winde, F., \u0026amp; Wade, P. (2006). \u003cem\u003eAn Assessment of Sources, Pathways, Mechanisms and Risks of Current and Potential Future Pollution of Water and Sediments in Gold-mining Areas of the Wonderfonteinspruit Catchment: Report to the Water Research Commission\u003c/em\u003e: Water Research Comission.\u003c/li\u003e\n\u003cli\u003eCorlin, L., Rock, T., Cordova, J., Woodin, M., Durant, J. L., Gute, D. M., . . . Brugge, D. (2016). Health Effects and Environmental Justice Concerns of Exposure to Uranium in Drinking Water. \u003cem\u003eCurrent Environmental Health Reports, 3\u003c/em\u003e(4), 434-442. doi:10.1007/s40572-016-0114-z\u003c/li\u003e\n\u003cli\u003eDavidson, C. (2003). \u003cem\u003eCatchment diagnostic framework for the Klip River catchment, Vaal Barrage, October 1998-September 1999.\u003c/em\u003e University of the Witwatersrand, Johannesburg,\u003c/li\u003e\n\u003cli\u003eDewar, D. (2019). Uranium mining: environmental and human health effects. In \u003cem\u003eNuclear non-proliferation in international law-volume IV\u003c/em\u003e (pp. 229-235): Springer.\u003c/li\u003e\n\u003cli\u003eDurand, J. F. (2012). The impact of gold mining on the Witwatersrand on the rivers and karst system of Gauteng and North West Province, South Africa. \u003cem\u003eJournal of African Earth Sciences, 68\u003c/em\u003e, 24-43. doi:https://doi.org/10.1016/j.jafrearsci.2012.03.013\u003c/li\u003e\n\u003cli\u003eDWAF. (2002). Department of Water Affairs and Forestry (DWAF), 2002. Radiological dose calculation and water quality evaluation guideline for domestic water user. Department of Water Affairs and Forestry guideline document, March 2002, Pretoria.\u003c/li\u003e\n\u003cli\u003eDzoma, B., Moralo, R., Motsei, L., Ndou, R., \u0026amp; Bakunzi, F. (2010). Preliminary findings on the levels of five heavy metals in water, sediments, grass and various specimens from cattle grazing and watering in potentially heavy metal polluted areas of the North West Province of South Africa. \u003cem\u003eJ. Anim. Vet. Adv, 9\u003c/em\u003e(24), 3026-3033.\u003c/li\u003e\n\u003cli\u003eEdayilam, N., Ferguson, B., Montgomery, D., Al Mamun, A., Martinez, N., Powell, B. A., \u0026amp; Tharayil, N. (2020). Dissolution and vertical transport of uranium from stable mineral forms by plants as influenced by the Co-occurrence of uranium with phosphorus. \u003cem\u003eEnvironmental science \u0026amp; technology, 54\u003c/em\u003e(11), 6602-6609.\u003c/li\u003e\n\u003cli\u003eEPA, U. \u003cem\u003eEnvironmental Protection Agency (1999), Cancer Risk Coefficients for Environmental Exposure to Radionuclides, Federal Guidance Report N. \u0026ordm; 13\u003c/em\u003e. Retrieved from\u003c/li\u003e\n\u003cli\u003eEPA, U. (1992). Guidelines for exposure assessment. \u003cem\u003eFederal Register, 57\u003c/em\u003e(104), 22888-22938.\u003c/li\u003e\n\u003cli\u003eFashola, M. O., Ngole-Jeme, V. M., \u0026amp; Babalola, O. O. (2016). Heavy Metal Pollution from Gold Mines: Environmental Effects and Bacterial Strategies for Resistance. \u003cem\u003eInternational Journal of Environmental Research and Public Health, 13\u003c/em\u003e(11), 1047. Retrieved from https://www.mdpi.com/1660-4601/13/11/1047\u003c/li\u003e\n\u003cli\u003eFedderke, J., \u0026amp; Pirouz, F. (2002). The role of mining in the South African economy. \u003cem\u003eSouth African Journal of Economic and Management Sciences, 5\u003c/em\u003e(1).\u003c/li\u003e\n\u003cli\u003eFord, M. (1993). Uranium in South Africa. \u003cem\u003eJournal of the Southern African Institute of Mining and Metallurgy, 93\u003c/em\u003e(2), 37-58.\u003c/li\u003e\n\u003cli\u003eFryer, M., Collins, C. D., Ferrier, H., Colvile, R. N., \u0026amp; Nieuwenhuijsen, M. J. (2006). Human exposure modelling for chemical risk assessment: a review of current approaches and research and policy implications. \u003cem\u003eEnvironmental science \u0026amp; policy, 9\u003c/em\u003e(3), 261-274.\u003c/li\u003e\n\u003cli\u003eGenthe, B., Kapwata, T., Le Roux, W., Chamier, J., \u0026amp; Wright, C. Y. (2018). The reach of human health risks associated with metals/metalloids in water and vegetables along a contaminated river catchment: South Africa and Mozambique. \u003cem\u003eChemosphere, 199\u003c/em\u003e, 1-9.\u003c/li\u003e\n\u003cli\u003eGiri, S., \u0026amp; Jha, V. (2012). Risk assessment (chemical and radiological) due to intake of uranium through the ingestion of drinking water around two proposed uranium mining areas, Jharkhand, India. \u003cem\u003eRadioprotection, 47\u003c/em\u003e(4), 543-551.\u003c/li\u003e\n\u003cli\u003eGupta, D. K., \u0026amp; Walther, C. (2020). \u003cem\u003eUranium in Plants and the Environment\u003c/em\u003e: Springer.\u003c/li\u003e\n\u003cli\u003eHakonson-Hayes, A. C., Fresquez, P., \u0026amp; Whicker, F. (2002). Assessing potential risks from exposure to natural uranium in well water. \u003cem\u003eJournal of environmental radioactivity, 59\u003c/em\u003e(1), 29-40.\u003c/li\u003e\n\u003cli\u003eHu, X., Zhang, Y., Ding, Z., Wang, T., Lian, H., Sun, Y., \u0026amp; Wu, J. (2012). Bioaccessibility and health risk of arsenic and heavy metals (Cd, Co, Cr, Cu, Ni, Pb, Zn and Mn) in TSP and PM2. 5 in Nanjing, China. \u003cem\u003eAtmospheric environment, 57\u003c/em\u003e, 146-152.\u003c/li\u003e\n\u003cli\u003eHuchzermeyer, M. (2009). The struggle for in situ upgrading of informal settlements: a reflection on cases in Gauteng. \u003cem\u003eDevelopment Southern Africa, 26\u003c/em\u003e(1), 59-73. doi:10.1080/03768350802640099\u003c/li\u003e\n\u003cli\u003eKamunda, C., Mathuthu, M., \u0026amp; Madhuku, M. (2016). Health Risk Assessment of Heavy Metals in Soils from Witwatersrand Gold Mining Basin, South Africa. \u003cem\u003eInternational Journal of Environmental Research and Public Health, 13\u003c/em\u003e(7). doi:10.3390/ijerph13070663\u003c/li\u003e\n\u003cli\u003eKamunda, C., Mathuthu, M., \u0026amp; Madhuku, M. (2018). Potential human risk of dissolved heavy metals in gold mine waters of Gauteng Province, South Africa. \u003cem\u003eJournal of Toxicology and Environmental Health Sciences, 10\u003c/em\u003e(6), 56-63.\u003c/li\u003e\n\u003cli\u003eKeith, S., Faroon, O., Roney, N., Scinicariello, F., Wilbur, S., Ingerman, L., . . . Diamond, G. (2013). \u003cem\u003eToxicological Profile for Uranium\u003c/em\u003e: Agency for Toxic Substances and Disease Registry (US), Atlanta (GA).\u003c/li\u003e\n\u003cli\u003eKrige, D. (1966). A study of gold and uranium distribution patterns in the Klerksdorp gold field. \u003cem\u003eGeoexploration, 4\u003c/em\u003e(1), 43-53.\u003c/li\u003e\n\u003cli\u003eKritzinger, A. (2017). SOCIO-ECONOMIC IMPACT ASSESSMENT OF THE PROPOSED CESSATION OF PUMPING AND ASSOCIATED CLOSURE OF THE UNDERGROUND WORKINGS OF THE EZULWINI OPERATIONS OF SIBANYE GOLD, GAUTENG PROVINCE. \u003cem\u003eReport prepared for Sibanye Gold\u003c/em\u003e.\u003c/li\u003e\n\u003cli\u003eMcCarthy, T. S. (2011). The impact of acid mine drainage in South Africa. \u003cem\u003eSouth African Journal of Science, 107\u003c/em\u003e(5-6), 01-07.\u003c/li\u003e\n\u003cli\u003eMeans, B. (1989). \u003cem\u003eRisk-assessment guidance for superfund. Volume 1. Human health evaluation manual. Part A. Interim report (Final)\u003c/em\u003e. Retrieved from\u003c/li\u003e\n\u003cli\u003eNjinga, R. L., Tshivhase, V. M., \u0026amp; Mathuthu, M. (2016). Chemical toxicity of surface-based drinking water sources due to natural uranium pollutant around princess gold mine environs in Roodepoort, South Africa. \u003cem\u003eExposure and Health, 8\u003c/em\u003e(4), 457-464.\u003c/li\u003e\n\u003cli\u003eNRC. (2009). Science and decisions: advancing risk assessment.\u003c/li\u003e\n\u003cli\u003eOkeyode, I., \u0026amp; Jibiri, N. (2013). Excess lifetime cancer risks associated with the use of sediments from Ogun River, Nigeria as building material. \u003cem\u003eResearch Journal of Physics, 7\u003c/em\u003e(1), 1-8.\u003c/li\u003e\n\u003cli\u003ePhillips, G. N., \u0026amp; Law, J. D. (2000). Witwatersrand gold fields: geology, genesis and exploration. \u003cem\u003eReviews in Economic Geology, 13\u003c/em\u003e, 439-500.\u003c/li\u003e\n\u003cli\u003eRadiation, U. N. S. C. o. t. E. o. A. (2000). Sources and Effects of Ionizing Radiation (New York: United Nations). In: Sales Publications.\u003c/li\u003e\n\u003cli\u003eRaji, I. B., Hoffmann, E., Ngie, A., \u0026amp; Winde, F. (2021). Assessing Uranium Pollution Levels in the Rietspruit River, Far West Rand Goldfield, South Africa. \u003cem\u003eInternational Journal of Environmental Research and Public Health, 18\u003c/em\u003e(16), 8466.\u003c/li\u003e\n\u003cli\u003eRoss, J.-H., \u0026amp; Dudel, E. G. (2008). Uranium loads and accumulation in a mine water contaminated wetland. \u003cem\u003eMine water and the environment\u003c/em\u003e, 225-228.\u003c/li\u003e\n\u003cli\u003eSch\u0026ouml;ner, A., Noubactep, C., B\u0026uuml;chel, G., \u0026amp; Sauter, M. (2009). Geochemistry of natural wetlands in former uranium milling sites (eastern Germany) and implications for uranium retention. \u003cem\u003eGeochemistry, 69\u003c/em\u003e, 91-107. doi:https://doi.org/10.1016/j.chemer.2007.12.003\u003c/li\u003e\n\u003cli\u003eTutu, H., Cukrowska, E., McCarthy, T., Mphephu, N., \u0026amp; Hart, R. (2003). \u003cem\u003eDetermination and modelling of geochemical speciation of uranium in gold mine polluted land in South Africa.\u003c/em\u003e Paper presented at the D. Armstrong, AB de Villiers, RLP Kleinmann, TS McCarthy \u0026amp; PJ Norton, Mine water and the environment. Proceedings of the 8th International Mine Water Association Congress, Johannesburg, South Africa.\u003c/li\u003e\n\u003cli\u003eTutu, H., McCarthy, T., \u0026amp; Cukrowska, E. (2008). The chemical characteristics of acid mine drainage with particular reference to sources, distribution and remediation: the Witwatersrand Basin, South Africa as a case study. \u003cem\u003eApplied geochemistry, 23\u003c/em\u003e(12), 3666-3684.\u003c/li\u003e\n\u003cli\u003eUSEPA. (1986). Guidelines for carcinogen risk assessment. \u003cem\u003eFederal Register, 51\u003c/em\u003e(185), 33992-34003.\u003c/li\u003e\n\u003cli\u003eWHO. (2001). Depleted uranium: sources, exposure and health effects \u003cem\u003eWorld Health Organization, No. WHO/SDE/PHE/01.1\u003c/em\u003e.\u003c/li\u003e\n\u003cli\u003eWinde, F. (2001). \u003cem\u003eSlimes dams as source of uranium contamination of streams\u0026ndash;the Koekemoer Spruit (Klerksdorp gold field) as a case study.\u003c/em\u003e Paper presented at the Conference on environmentally responsible mining in Southern Africa.\u003c/li\u003e\n\u003cli\u003eWinde, F. (2004). \u003cem\u003eInventory of uranium sources and pathways in the catchment. In: Coetzee, H (compiler): An assessment of sources, pathways, mechanisms and risks of current and potential future pollution of water and sediments in gold-mining areas of the Wonderfonteinspruit catchment\u003c/em\u003e. Retrieved from Water Research Commission Report No 1214/1/06:\u003c/li\u003e\n\u003cli\u003eWinde, F. (2011). Challenges in assessing uranium-related health risks: Two case studies for the aquatic exposure pathway from South Africa\u0026ndash;Part I: Guideline and toxicity issues and the Pofadder case study. In \u003cem\u003eThe New Uranium Mining Boom\u003c/em\u003e (pp. 529-538): Springer.\u003c/li\u003e\n\u003cli\u003eWinde, F., \u0026amp; de Villiers, A. B. (2002). The nature and extent of uranium contamination from tailings dams in the Witwatersrand gold mining area (South Africa). In \u003cem\u003eUranium in the aquatic environment\u003c/em\u003e (pp. 889-898): Springer.\u003c/li\u003e\n\u003cli\u003eWinde, F., \u0026amp; Sandham, L. (2004). Uranium pollution of South African streams\u0026ndash;An overview of the situation in gold mining areas of the Witwatersrand. \u003cem\u003eGeoJournal, 61\u003c/em\u003e(2), 131-149.\u003c/li\u003e\n\u003cli\u003eWinde, F., \u0026amp; van der Walt, I. J. (2004). The significance of groundwater-stream interactions and fluctuating stream chemistry on waterborne uranium contamination of streams - a case study from a gold mining site in South Africa. \u003cem\u003eJournal of Hydrology, 287\u003c/em\u003e(1-4), 178-196. doi:10.1016/j.jhydrol.2003.10.004\u003c/li\u003e\n\u003cli\u003eWinde, F., Wade, P., \u0026amp; van der Walt, I. J. (2004). Gold tailings as a source of waterborne uranium contamination of streams - The Koekemoerspruit(#) (Klerksdorp goldfield, South Africa) as a case study - Part I of III: Uranium migration along the aqueous pathway. \u003cem\u003eWater Sa, 30\u003c/em\u003e(2), 219-225. Retrieved from \u0026lt;Go to ISI\u0026gt;://WOS:000222001100010\u003c/li\u003e\n\u003cli\u003eWWF-SA. (2016). Water: Facts and Futures-Rethinking South Africa's Water Future. In: WWF-SA Cape Town.\u003c/li\u003e\n\u003cli\u003eZamora, M. L., Tracy, B. L., Zielinski, J. M., Meyerhof, D. P., \u0026amp; Moss, M. A. (1998). Chronic ingestion of uranium in drinking water: a study of kidney bioeffects in humans. \u003cem\u003eToxicol Sci, 43\u003c/em\u003e(1), 68-77. doi:10.1006/toxs.1998.2426\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 3 is not available with this version\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"uranium, dose, exposure, pathways, cancer, risk, hazard, gold, mining","lastPublishedDoi":"10.21203/rs.3.rs-1177732/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1177732/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eUranium, U, as a toxic element has detrimental radiological and chemical impacts on human health when ingested at elevated concentration in water. The establishment of gold mining operations upstream to the Rietspruit is assumed to be a source of uranium into this water body which flows through residential and agricultural land. Water samples from the stream were collected and analysed using inductively coupled plasma mass spectrometry to determine the concentration of U. Uranium concentrations above South African regulatory limit were recorded in the stream water which is used for domestic, agricultural and religious activities as observed during field visits. Results from calculations showed that the maximum annual effective dose within this mining environment was above 1 mSv/year for all age groups. Furthermore, the probability of radiological risk is lower than the chemical risk which is due to the ingestion of U in the Rietspruit water. The chemical risk analysis showed that within 24 km of this mining environment, stream users are in danger of U chemical toxins therefore, it is important to educate the stream users about their health risk of U and recommend adequate interventions by relevant government agencies to this effect.\u003c/p\u003e","manuscriptTitle":"Assessing Health Risk Associated with Uranium in Rietspruit Water, Far West Rand Goldfield, South Africa","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-12-22 15:38:17","doi":"10.21203/rs.3.rs-1177732/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a99f5347-abee-4493-8cdf-fd1dd48264ad","owner":[],"postedDate":"December 22nd, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":9316461,"name":"Health Policy"},{"id":9316462,"name":"Internal Medicine"},{"id":9316463,"name":"Toxicology"}],"tags":[],"updatedAt":"2022-01-04T13:27:53+00:00","versionOfRecord":[],"versionCreatedAt":"2021-12-22 15:38:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1177732","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1177732","identity":"rs-1177732","version":["v1"]},"buildId":"cBFmMYwuxLRRLfASyISRj","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}