Comparative quality assessment of the drinkability of abandoned lake water with ground and municipal water in Raichur, Karnataka, India

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Potable water quality from the surface or ground must comply with the national regulatory limits. Eleven abandoned lakes, sixteen grounds, and five drinking water samples in the Raichur district were analyzed. Our findings of abandoned lake water included 14 physical-chemical parameters (mg/L): Total dissolved solids TDS(149.4–1298), Total hardness TH (77.31–401.31), Total alkalinity TA (89.44–430), Cl − (13.33–429.86), F − (0.16–0.89), Ca 2+ (26.98–121.03), Mg 2+ (12.23–68.1), SO 4 2− (15.11–190.9), NO 3 − (0.1–5.64), DO (38.3–60.12), COD (12.12–200.0), BOD (9.05–33.13) Free residual chlorine FRC(<1 mg/L) and pH (7.09–8.8). Groundwater: TDS (330.0–8724), TH(6.2–1518), TA(10–587mg/L), Cl − (25.27–366.0), F − (0.31–3.94), Ca 2+ (1.6–527.0), Mg 2+ (1.12–241.0), SO 4 2− (7.56–440.0), NO 3- (0.51–87.0) FRC(<1) and pH (6.96–7.9). Drinking water: TDS (36–891.67), TH(24.50–370.0), TA(18.89–340), Cl − (16.99–988.0), F − (0.09–1.83), Ca 2+ (12.83–136.8), Mg 2+ (2.83–56.59), SO 4 2− (8.1–170.78), NO 3 - (3.1–19.82) FRC(<1–80), and pH (7.05–7.47). Ninety percent of the abandoned lake water samples met the acceptable limits for parameters TDS, TH, TA, pH, Cl − , F − , Ca 2+ , SO 4 2− , NO 3 - , and Mg 2+ . The bacteriological quality of lake water samples showed coliform 30–210 total MPN/100 mL, and turbidity exceeded the acceptable limits (0–5 NTU). Sixty percent of the groundwater samples exceeded the permissible limits for TDS, 100% for magnesium, 75% for fluoride, 62.15% for calcium, and 40% for nitrate content. Five of the 16 groundwater samples analyzed for heavy metals showed an arsenic content of 0.094 mg/L. All the municipal water samples analyzed met the acceptable limits for physicochemical parameters and microbial load, indicating safe drinkability. This assessment outlines the future treatment needed for the restoration of abandoned lakes. Water quality acceptable limit Physicochemical parameters biplot Heavy metals microbial load Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction In the past, lakes in India served as primary sources for drinking, agriculture, and industry. Additionally, they serve as recharge zones for groundwater aquifers, flood cushions, and effluent absorbers. Numerous waterways have either disappeared or are currently in the process of disappearing. The primary cause is the extraction of lake water for real estate purposes in cities in India, including Hyderabad, Bangalore, and Ahmadabad. Despite the numerous lakes in these cities, survival is restricted (Ramachandra et al., 2018). In villages, cultivable land is used for setting up factories. Previously, the farmers utilized the lake silt as fertilizer, but now chemical fertilizers are used. Therefore, the silt is not removed but instead accumulates in the lakes. Increased urbanization and industrialization affect lake water quality deterioration across the Indian subcontinent. The degradation of lakes makes it unsafe to use Water for farming and drinking. UNICEF says that providing drinking water is still challenging in Asian countries, especially India, where 63 million people cannot access it (Hokkanen et al., 2018). Also, South Africa and other wealthy nations have terrible problems with having adequate fresh Water (Abbott et al., 2019). If nothing is done right away, two-thirds of the world's people will have trouble getting enough Water in the future (Aniyikaiye et al., 2019). Alternate to lake water, groundwater is an alternate source of drinking water in India, where approximately 251 billion cubic meters are used annually. Irrigated agriculture (60%) and drinking water stores (70–85%) depend on groundwater. Six hundred million people are experiencing high to extreme water stress, with an estimated 2,000 people dying each year due to a shortage of access to drinking water (Puri & Kumar, 2012). The water quality index (WQI) ranks India 120th out of 122 countries. Food production is also at risk because many farmers struggle to cope with water resources efficiently. In recent decades, groundwater's excessive and mindless withdrawal has triggered a series of crises. Excessive drilling of bore wells and mechanized pumping has led to diminishing groundwater aquifers in many regions of the country, termed dark zones (Kishore et al., 2020). Water quality analysis is frequently needed to assess surface and groundwater quality. The physicochemical properties of Kashmir Lake have led to a decline in quality due to a delay in quality restoring strategy (Kumar et al., 2022). An evaluation of artificial rain-fed Sukhan Lake in the Indian city of Chandigarh revealed that quality deterioration decreased from good to marginal, and regular monitoring of lake water quality was recommended (Jindal & Wats, 2022). The water quality of the sacred glacial-fed lakes in remote areas of the Himalayas has proven to be excellent and a good reference for other lakes in India (Sharma & Kumar, 2017). Analysis of contaminants in typical reservoirs on the Yellow River, China, to examine the geographical and temporal fluctuations in water quality (Loizidou & Kapetanios, 1993). They used the water quality index as a tool for the assessment. There is a report of anthropogenic causes that have a discernible impact on the groundwater quality around the coastal city of Tuticorin in southern India, as evidenced by the Water Quality Index (Manjushree et al., 2009). The study provided much-needed baseline data for reviewing issues related to water quality. In general, India's water systems are in a state of equilibrium, with the potential to either return to a sustained system or decline. In conclusion, the aquatic ecosystem in India is confronted with various threats, such as over-abstraction and river flow regulation, increasing pollution, encroachment, degradation of watersheds, and limited conservation efforts. Different methods have been established to evaluate water quality in numerous studies, such as multivariate statistical methods (Bear, 1979), modeling techniques (Doneen, 1964), and multi-metric index-based methods (Foster, 1995). Various researchers Karanth, 1987 & Kumar et al. 2011 have further developed the WQI, initially designed by Foster, 1998, and Hem, 1985. While there are formulas to figure out the WQI, they take a lot of different physical and chemical factors and turn them into a single number that shows the level of water quality. It removes the differences between the factors used separately in the assessment (Babiker et al., 2007). The Raichur district of Karnataka, India, is between two large rivers: Krishna on the northern border and Tungabhadra on the southern border. More than 95 of the sub-district's 171 villages are experiencing an extreme drinking water problem. People in Madagiri, Hallihosur, Gavittu, Haravi, Jakkaladinni, and Manvi towns are forced to drink fluoride-contaminated Water, which causes joint pain and fluorosis (Ganiger, 2014). In the same way, villages in the Devadurga sub-district have had the worst problem with drinking water since the drought in 1972–73. The Krishna River has dried up for the first time in forty years. Depending on rivers, most villages and towns in Devadurga are having trouble getting clean Water (Chowdhury et al., 2016). To evaluate the abandoned lake water for its potability and to reduce the dependence on groundwater as a source of drinking water, a study was carried out primarily with the collection from various locations of Raichur and to analyze the microbiological and physicochemical characteristics according to the protocol of BIS. Materials and methods Chemicals NIST traceable reference materials were purchased: fluoride (HC90463814), sulfate (HC90775013), nitrate (HC90701111), potassium dichromate (Merck-192403U), pH 4.0 (HC99926875), pH 7.0 (HC02254877) and pH 10.0 buffer solutions (HC97816109) were purchased from Merck, Bangalore, and calcium carbonate (192410M) and sodium carbonate (192405R) and sodium chloride (192406T ) from Supelco, Merck India. Class A glassware was used for the experiments. Lead, Cadmium, Mercury, Nickel, Total chromium, and Total Arsenic standards were purchased from Perkin Elmer, USA. Sample collection The Raichur district is 454 km from Bengaluru and is 407 m above sea level. It is divided into five sub-districts for administrative purposes. In this study, we collected three sub-district samples for ground and surface water sampling. Groundwater samples from bore wells were used for dissolved oxygen (DO) determination, and the lake water was filled in glass bottles (250 ml) and added with Winkler's reagent in the site area. Eleven lakes named Usukuhanumappa, Neerbaavikunta, Aamthalab, Khakina, Jadarapete, Halepete, Nelhal, Dinni, Hunasihal, Sri Ram Nagar, and Rampur stations from June–July 2024. Sampling was performed once during the study period between 11.00 am and 5.00 pm. The samples were taken from a point near the middle of the lake, and the sampling locations shown in Fig. 1 were selected based on the agricultural activities in the vicinity and possible runoff into the river. The Raichur map and the location sites were created using ArcGIS version 10.2, Bangalore, India. Analytical methods The samples for determining the BOD were collected in 250 ml dark-colored bottles. The samples were analyzed using the American Public Health Association (Lipps and Howland, 1995) and Bureau of Indian Standards (BIS) 10500:2012 standard methods. The turbidity and pH were analyzed using pH and turbidity meters (HANNA HI 5221–02) (HI 83414 turbidity meter and HI), and total dissolved solids (TDS) were measured via the gravimetric method (IS 3025 Part 16). The total hardness, calcium (Ca 2+ ) content (IS 3025 Part 40), and magnesium (Mg 2+ ) content (IS 3025 Part 46) were determined by titration method using a standard EDTA solution such as CaCO 3 (IS 3025 Part 21). Chloride (Cl − ) was determined via colorimetric titration using standard AgNO 3 (IS 3025 Part 32). The total alkalinity was estimated with sulfuric acid (0.02 N) (IS 3025 Part 23). The fluoride (F - ) content via the APHA method, 23rd Edition 4500 D, the sulfate (SO 4 2− ) content via the IS 3025 part 24, and the nitrate (NO 3- ) content via the IS 3025 part 34 were determined via a UV spectrophotometer. DO was determined via Winkler's procedure (APHA, 1998; part 4500 – OC, p. 4-131), and the chemical and biological oxygen demands were determined via the APHA method. The methods taken from BIS and APHA were verified in the laboratory for linearity, precision, repeatability, and accuracy. The accuracy of the analyte was confirmed by recording the absorbance of the samples against the known concentration of the standards via a Perkin Elmer Lambda 365 N4100020 UV–visible spectrophotometer. It was calibrated according to the USP43 (857) protocol. Enumeration of total coliform and E. coli in surface water, drinking Water, and groundwater was carried out by the Most Probable Number (MPN) technique (IS 1622–2019). The heavy metals were analyzed using ICP-MS (Perkin Elmer Nexion 350X) according to AOAC 2015.01 (20th edition 2016). Analytical precision The physicochemical data was analyzed through linear regression, ANOVA, Duncan multiple range test, and principal component analysis (PCA). The proficiency tests for parameters were conducted by National accredited testing agencies such as Global PT Provider Private Limited, New Delhi, and Aashvi Proficiency Testing and Analytical Services, Hyderabad, India, in the years 2022, 2023, and 2024 (supplementary data Table 1 ). The measurement of uncertainty was calculated using the guidelines of Eurachem, 1989 (supplementary data Table 2 ). Results and Discussion A total of 11 surface water samples, 16 groundwater samples from sub-districts of Raichur sites (Fig1), and five drinking water samples supplied from two different rivers, particularly the Narayanapur Reservoir of Krishna river right bank (15.754239ºN, 80.897270ºE) and the Tungabhadra River (14°0′30″N 75°40′27″E) to the residents of Raichur town were tested for water quality parameters and distinguished with the acceptable and permissible standards in accordance to Bureau of Indian Standards (BIS) Table 1. The physical, chemical, and organic factors that determine the quality of Water and keep it that way are all taken into account here. Different factors like TDS, pH, total hardness, alkalinity, Cl − , Fl − , BOD, COD, DO, SO 4 − 2 , Ca + 2 , Mg + 2 , and NO 3− are measured and compared to the limits set by organizations like the CPCB, WHO, BIS, and others. Then, the changes in these parts are compared to the current standards set by the Bureau of Indian Standards (BIS) for drinking water quality (Table 1 ). Table 1 Acceptable and permissible limits for drinking water quality characteristics by the Bureau of Indian Standards (BIS 10500:2012). Characteristic (mg/L) Acceptable Limit Permissible Limit pH 6.5–8.5 * Total dissolved solids (TDS) 500 2000 Turbidity, NT units 1 5 Calcium (Ca + 2 ) 75 200 Chloride (Cl - ) 250 1000 Fluoride (F - ) 1.0 1.5 Magnesium (Mg + 2 ) 30 100 Nitrate (NO 3 - ) 45 * Sulphate (SO 4 -2 ) 200 250 Total alkalinity (CaCO3) 200 600 Total hardness (CaCO3) 200 600 Free residual chlorine (Cl 2 ) 0.2 1 Chemical oxygen demand (COD) 250 * Biological oxygen demand (BOD) 30 350 Dissolved oxygen (DO) 6 13–14 *Indicates no relaxation pH and TDS variation in lake, ground, and municipal water samples The acceptable pH limit for drinking Water from any source ranges from 6.5 to 8.5. Our findings revealed that the groundwater samples collected from the Raichur city and sub-districts varied from 6.96 to 7.99 (Fig. 2 ). The lake water pH ranged between 7.63 and 8.8 units. Only one was above the acceptable limit. Among the 11 lakes, only Aamthalab (SW3) lake water had a pH of 8.8. This is caused by sewage disposal for more than 25 years and water draining from heavily fertiliser-fed nearby agricultural fields. The pH of the municipality-supplied drinking water also ranged from 7.11–7.29, and no deviation from the acceptable range. The pH values of the GW, DW, and SW samples did not deviate much, as the values fell between the permissible limits of 6.5–8.5 units, and none reached values above or below the limits. The TDS of the groundwater samples in the Raichur district ranged from 330 mg/L to 8724 mg/L (Fig. 3 ), meaning that most samples were higher than the maximum allowable level and could not be used for drinking. As stated in the BIS standard, the maximum level of TDS contaminants in drinking water is 500 mg/L, and it can be up to 2000 mg/L if no other source is available. However, the WHO says a TDS of up to 500 mg/L is the best level, and up to 1,500 mg/L is the most used. Generally, dissolved solids in any water source comprise inorganic salts and small amounts of organic matter. High TDS values of up to 8000 mg/L in groundwater account for natural resources, and the Raichur region is at the centre of the Deccan Plateau and features high salt content. The groundwater tends to contain high levels of dissolved solids, mainly high amounts of calcium and magnesium salts. Although high concentrations of dissolved solids are usually not a health hazard above 900–1000 mg/L, limiting the Water becomes unacceptable and nonpalatable. Thus, out of the 16 GW samples analyzed for TDS, 14 samples had TDS concentrations greater than 1000 mg/L, which is highly above the acceptable limit for drinking. This finding indicates that 87.5% of the GW samples are not potable. Seventy-two percent of the lake water samples had TDS values less than 1000 mg/L, and 54.5% were below the acceptable limit and were all suitable for drinking purposes. The five lake water samples, i.e., Neerbavikunta (SW2), Aamthalab (SW3), Khakina (SW4), Jadarapete (SW5), and Halepete (SW6), are above 500 mg/L, which is more of a concern. It would be reasonable to know that they have high TDS values, as these lakes have been used as potable water for decades. The drinking water supplied by the municipality has three samples above the acceptable limit, and it becomes questionable whether such high TDS-containing water is provided to Raichur City and whether strict monitoring of Water for TDS is needed. Variation of turbidity, total hardness, and total alkalinity (CaCO 3 ) in ground, surface, and drinking water. The turbidity of the lake water reaches a range of up to 688 NT units (Fig. 4 ), which shows that the lake water across the district is highly turbid due to algae and other prokaryotes that grew as the water samples visibly had a green colour. In addition to being aesthetically unappealing, it is a significant health concern and provides food and shelter for pathogens. The turbidity of groundwater collected from the bore wells was less than one NT unit as expected, and in the case of drinking Water, it was less than 5 NT units. The total hardness of surface water varies from 77 to 401 mg/L, and 37.5% of groundwater samples are classified as hard (Sawyer & McCarty, 1967). Thus, 62% of the groundwater samples were moderately hard. In the case of surface water, 72% of the samples were soft, and 27% were moderately hard to completely hard, owing to the presence of alkaline ground elements such as calcium and magnesium. All the groundwater samples are above the acceptable limit, and 54% of the surface water samples are below the 200 mg/L concentration, which lies within the permissible limit (Fig. 3 ). Among the municipal drinking water supplies, two of the five samples had TDS concentrations greater than 200 mg/L, which is unacceptable for drinking. Thus, overall, surface water samples are better in the case of total alkalinity. Chloride and fluoride variation in the contents of ground, surface, and drinking water Chloride and fluoride levels in Raichur district sub-district GW, SW, and DW samples are shown in Fig. 4 . SW chloride concentration ranged from 13.33 to 430 mg/L when BIS allowed 250 mg/L and 1000 mg/L. Neerbavikunta (SW2), Aamthalab (SW3), Jadarapete (SW5), and Halepete (SW6) lake samples are above the acceptable limit, but within 1000 mg/L. If the chloride concentration is above 250 mg/L, the Water tastes salty and would be unfit for irrigation (Chigor et al., 2013). The sustainability of agriculture and aquaculture is always in danger (Puri & Kumar, 2012). Only 50% of GW samples were < 250 mg/L. Two of the five drinking water samples had values above 250 mg/L, while three were below the limit. A high chloride level causes corrosion in plumbing pipe variations, as well as in water heaters. Chloride in groundwater can originate from various causes, such as weathering, leaching of igneous rock and soil, salt carried by wind during precipitation, discharge of waste from homes and industries, municipal effluents, and other similar sources. The study region exhibits chloride values ranging from 12.01 to 539.87 mg/L, as shown in Fig. 4 . The groundwater sample of the Sindhanur sub-district (GW13) contains a significantly high chloride content, and the ideal chloride limit for drinking water is 250 mg/L. Surplus chloride presence in groundwater is commonly used as a pointer of pollution and a tracer of contamination (Loizidou & Kapetanios, 1993). Surface water samples (SW2, SW3, SW5, and SW6) have Cl- concentrations of more than 250 mg/L, which substantially correlate with Na content and specific conductance (data not shown). The determination of chloride may be used to detect the interruption of water of varying compositions or to track and measure the volume of water mass movement. The fluoride parameter is subject to a 1.0 mg/L level set by the BIS, a prerequisite for approval. In the dearth of an alternative source, 1.5 mg/L is permissible. However, the fluoride levels in surface water samples were less than 1.0 mg/L, which is acceptable, and those in groundwater were 50% above the acceptable and permissible limits. Therefore, consuming such contaminated water is a health hazard. The drinking water supplied by the municipality is 20%, which is above the allowable limit. Sulphate and nitrate content variation in ground, surface, and drinking water Natural waters contain sulphate as one of their primary anions. The sulphate concentration in potable Water is limited to 200 mg/L according to BIS 10500:2012. The sulphate concentrations in the ground, surface, and potable Water were 45.90–440 mg/L, 15–169 mg/L, and 14–154 mg/L, respectively. The drinking and surface water samples had low to normal sulphate concentrations, and 37.5% of the GW samples had sulphate concentrations higher than usual. Thus, the concentrations of sulphate in all the sources of Waterfall are under the recommended limits of 200 mg/L (BIS) and 250 mg/L (250 mg/L) by the USEPA. The acceptable limit for nitrate concentration is 45 mg/L, and anything above is not given any relaxation. The nitrate contents of the GW, SW, and DW samples ranged from 0.5–86 mg/L, 0.1–5 mg/L, and 1.2–19 mg/L, respectively. The nitrate concentration in the lakes of the primary Raichur district was 0.75–1.6 mg/L (Fig. 5 ), with an average value of 0.76 mg/L, suggesting that the acceptable range contained all samples. Out of the 16 GW samples, only six presented nitrate contents above the permissible limit, and 10 were within the limit. Thus, groundwater must be treated via an ion exchange column to remove nitrate. All the drinking and surface water samples were safe for nitrate content. Magnesium and calcium ions variation in-ground, surface, and drinking water The magnesium level is higher than the acceptable limit in 100% of the GW samples (Fig. 6 ). The readings were within the acceptable range in both the SW and DW samples. Calcium and magnesium levels are negatively correlated with human blood pressure, and the public is motivated to obtain information regarding the mineral composition of bottled or packaged water. The key to decreasing the calcium and magnesium ions leading to hardness is to use an ion exchange column or water softener device at the entrance point or within the households. Magnesium and calcium are the most profuse elements in natural soils, including surface and groundwater. They are found chiefly as bicarbonates and, to a lesser extent, sulphate and chloride. The Ca2 + content ranges from 90 to 526 mg/L (Fig. 6 ). The relatively high Ca2 + content in groundwater sample GW2 was 526.4 mg/L. Drinking water tests revealed that a few groundwater samples exceeded the allowable level. 62.5% of the groundwater samples collected from the sampling sites were above the maximum permissible limit of 200 mg/L for calcium, whereas 37.5% were below the legal range. Only two of the eleven surface water samples were above the allowable level, while the remaining samples were safe to drink. The high Ca2 + content can cause gastrointestinal pain in adults and is unsuitable for residential use since it promotes scaling and crust formation in boilers/heaters. Magnesium concentration ranges from 1.4 to 106.4 mg/L. The maximum acceptable limits for Mg2 + concentration in drinking water are 100 mg/L (ISI 1993) and 150 mg/L (WHO 2004). Every groundwater sample surpassed the magnesium content limit of 100 mg/L. COD, BOD, and DO variations in surface water samples For aerobic life forms, the water in these places does not look clean, but there is the presence of fish, indicating lakes are not contaminated with chemicals; natural stream cleaning systems need enough oxygen. It can be seen in Fig. 7 that the COD of the surface water samples is less than 250 mg/L, and the BOD is below the acceptable level. The biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) show how wastewater has affected the ecosystem lake water of Aamthalab. Having enough dissolved oxygen in water is essential for maintaining the health of the lakes. Overall, the lakes are not polluted, and Raichur is less industrialized than the other Karnataka districts, especially Bangalore. The surface water had dissolved oxygen levels between 35 and 60 mg/L in subdistricts of Raichur, which is higher than the acceptable range of 6.5 to 8 mg/L. Aquatic organisms experience stress when the dissolved oxygen level in Waterfalls is below 5.0 mg/L. The tension increases as the concentration of the substance decreases. Consequently, dissolved oxygen levels below 1–2 mg/L for a few hours can lead to the significant death of aquatic life, especially fish. The faecal coliform bacteria in the surface water samples suggested that the Water had been contaminated with faecal material (Data not shown). Other water-borne pathogens that cause typhoid fever, viral and bacterial gastroenteritis, and hepatitis A were identified (data are not presented). Principal component analysis interpreted the information of a set of fourteen data parameters into information predicting the drinkability of drinking water, groundwater, and surface water samples. The top right side of Fig. 8 shows that the total hardness was high toward the non-permissible limit, especially in the groundwater samples (GW12, GW2, and GW6). This trend is also observed for TDS, which is more significant in the GW7, GW10, GW11, and GW16 samples. Similar samples formed a cluster, and the different samples were separated. The plot shows that surface water samples, especially SW2, SW3, SW4, SW5, and SW6, had turbidity levels toward the non-permissible limits. Similar results were demonstrated in dissolved oxygen and biological oxygen demand parameters. The remaining parameters, such as pH, turbidity, chloride, total hardness, calcium, magnesium, and total alkalinity, are near zero coordinates and are within the cluster. The total hardness and TDS were distinctly greater and central, reflecting parameters in groundwater than in drinking and surface water. Similar observations were found in the water quality Vishav stream of the Jhelum River of Kashmir Himalaya (Arafat et al., 2022). Microbial and Heavy metal contaminants The standard heavy metals of concern in lake water, drinking Water, and groundwater included lead, cadmium, arsenic, mercury, chromium, and nickel. The ICP-MS results (Table 2 ) showed that the drinking and surface water samples did not show heavy metals exceeding the acceptable limit, whereas groundwater showed arsenic content from 0.01–0.1 mg/L. Five of the 16 GW samples analyzed showed an arsenic content of 0.094 mg/L. The bacteriological quality of lake water samples showed 30–210 total Coliform MPN/100 mL and 9–88 E.coli , whereas groundwater and drinking water had 0–2 colonies (Table 3 ), which is not acceptable as per BIS specifications. Table 2 Heavy metal concentration in the surface, ground, and drinking water Samples Lead Cadmium Mercury Nickel Total Chromium Total Arsenic (mg/L) Samples Lead Cadmium Mercury Nickel Total Chromium Total Arsenic (mg/L) 0.01 0.003 0.001 0.02 0.05 0.01 SW1 - - - - - 0.002 SW2 - - - - - 0.006 SW3 - - - - - 0.003 SW4 - - - - - 0.002 SW5 - - - - - 0.004 SW6 - - - - - 0.003 SW7 - - - - - 0.008 SW8 - - - - - 0.006 SW9 - - - - - 0.002 SW10 - - - - - 0.001 SW11 - - - - - 0.008 GW1 - - - - - 0.007 GW2 - - - - - 0.04 GW3 - - - - - 0.60 GW4 - - - - - 0.62 GW5 - - - - - 0.45 GW6 - - - - - 0.08 DW1 - - - - - 0.55 DW2 - - - - - - DW3 - - - - - - DW4 - - - - - - DW5 - - - - - - Table 3 Comparative bacteriological quality of surface water, groundwater, and drinking Water as per BIS 10500: 2012. Samples Total Coliform (MPN/100 mL) E.coli (MPN/100 mL) BIS requirements SW1 210 65 Shall not be detectable in any 100 mL sample SW2 150 40 SW3 30 11 SW4 45 14 SW5 106 88 SW6 201 65 SW7 25 9 SW8 106 53 SW9 102 48 SW10 135 56 SW11 135 61 GW1-GW 16 0–2 0–1 DW1 to DW5 0–1 0 In the district of Raichur, India, the surface water of abandoned lakes has been dangerously altered or degraded at a more significant pace than their restoration. The total dissolved solids of the surface waters of Usukuhanumappa (SW1), Nelhal63 (SW7), Dinni 64 (SW8), Hunasihal 65 (SW9), Sri Ram Nagar66 (SW10) and Rampur 67 (SW11) are less than 500 mg/L, which is highly acceptable and accounts for 50% of the lakes that possess good physicochemical properties and are suitable for drinking purposes. The pH values of the surface waters of Usukuhanumappa (SW1), Neerbavikunta (SW2), Khakina (SW4), Jadarapete (SW5), Halepete (SW6), Hunasihal 65 (SW9), Sri Ram Nagar66 (SW10) and Rampur 67 (SW11) were in the acceptable range of 6.5–8.5, and the pH values of the groundwater samples (GW1–GW16) did not vary from the normal range. Twenty-five per cent of all the groundwater samples are above the permissible limit of 2000 mg/L, especially the Rampur (GW10), Askihal (GW11), Sharanama Bore (GW13), and K. Banadesh (GW16) samples. None of the groundwater samples were within an acceptable range. These findings match the lakes of Nagpur, India, where the National Environmental Engineering Research Institute (NEERI) certifies that 45% of the lake water is safe and suitable for drinking and that all the groundwater samples have TDS above the permissible level and are unfit for drinking. As water scarcity is an acute environmental problem, the focus is on improving existing water sources, particularly lakes, and employing quality determination for improvement and restoration (Magesh & Chandrasekar, 2011). The lack of use of lake water for drinking has often led to its deterioration apart from extreme pollution. These are made in lakes across Raichur city as cesspools. Concerning turbidity, the abandoned lake water samples contained more than 9.38 NT units, a few of which included up to 688 NT units due to algal growth. Effective treatment is needed for all polluted lakes to ensure they become suitable for drinking. Coincidently, the groundwater does not have turbidity issues. The chloride content of the lake water ranged from 13.33–430 mg/L, and 63% of the samples were above the permissible limits, and there was no discrepancy regarding the level. Slightly the water is salty and unpleasant to drink. The groundwater scenario is similar, as 50% of the samples are within the acceptable range and cannot be used for drinking. The chemical oxygen demand (COD) of the surface water samples collected across Raichur city was less than 1000 mg/L, indicating high pollution. This also suggests that spills, runoff, or sewage discharges contaminate surface water. Similarly, biochemical oxygen demand (BOD) is a commonly used index for determining water quality and indicates the overall concentration of organic substances. These results suggest that the decomposition of waste and bacteria and low quality resulted from values exceeding 5 mg/L. Water pollution is indicated by dissolved oxygen (DO) concentration less than 6.6–8 mg/L. The water is suitable for consumption after a specific treatment when the concentration is less than 1000 mg/L. It is necessary to detect intermediate investigative action on E. coli or total coliform bacteria. An even more precise indicator of faecal contamination is the presence of E. coli. The current study indicated that the lake water of the Raichur district and its sub-districts Manvi, Deodurga, Lingasugur, and Sindhanur exhibited high pH and high alkalinity, while the other parameters were within the tolerance limits recommended by the World and ISI standards. The comprehensive assessment of water quality necessitates the evaluation of toxicological components, including heavy metals, apart from physical, chemical, and biological components. Most groundwater samples contained fluoride concentrations ranging from 0.31 to 3.94 mg/L. Dental and skeletal fluorosis and passive bone fracture increase due to high fluoride levels. Surface water samples of the Raichur district had excellent fluoride concentrations lower than one mg/L (recommended value for drinking). The drinking water supplied to the southern Raichur district had one sample above 1.5 mg/L, making it unfit for drinking, whereas 75% of the groundwater samples in the Raichur district had fluoride values above one mg/L, indicating unsuitability for drinking. The variation in sulfate and nitrate contents in surface water was within the acceptable range and made it suitable for drinking, unlike in groundwater, where 37.5% are above the limits. The physical and chemical parameters for surface water are acceptable. However, the dissolved oxygen content was above the permissible limit. Thus, turbidity, color, DO, COD, BOD, or bacterial count do not affect surface water quality. If this Water has to be suitable for drinking, then possible pesticides and heavy metals must be checked for presence. The concentration of pollutants has increased due to the loss of water volume in lakes by encroachment in and around them. The government needs to clean the plants for the Water in the big lakes. So, water quality improves, and the public uses lake water as a primary drinking water source rather than groundwater. Monitoring the lakes will fetch small amounts of information, whereas the legal and administrative systems will take the right follow-up actions. The general public desires drinking water with minimum TDS and hardness. Softwater does not corrode and does not build up scales. The load of human dwellings along the lake shores has been recognized as the primary cause of environmental degeneration of the Aam thalab (Rohini et al. 2016). The Aam Thalab in Raichur is an example of one of the first Indian artificial lakes built around 1292 AD and the only drinking water source from 1960 to Raichur town. In the past sixty years, the urban population has increased, degrading the lake water quality beyond recovery. Encroachment, silting, weed infestation, extensive disposition of solid wastes by the population, and neglect by the district administration have made the lake into a dumping body for biological and chemical effluents (Chashoo et al., 2020). Conclusions The load of human dwellings along the lake shores has been identified as the primary cause of environmental degeneration of the Aam Thalab Lake (Rohini, 2016). The Aam Thalab in Raichur is an example of one of the first Indian artificial lakes built around 1292 AD and the only drinking water source from 1960 to Raichur town. The urban population rise in the past sixty years has degraded the lake water quality beyond recovery. Encroachment, silting, weed infestation, extensive disposition of solid wastes by the population, and neglect by the district administration have transformed the lake into a dumping body for biological and chemical effluents (Chashoo et al., 2020). The water quality of the lakes of Raichur district has undergone gruesome anthropogenetic pressure for the last six decades. Over the years, turbidity, microbial load, dissolved oxygen, BOD, and COD concentration have increased enormously. The lakes have become hyper-eutrophic at several sites, severely affecting the lake ecosystem with no fish and other zooplankton. The remaining parameters, such as fluoride, chloride, alkalinity, pH, total dissolved solids, calcium, magnesium, and heavy metals, are within acceptable limits. Lake water can be treated and used for drinking, reducing our dependence on groundwater. Comparatively, the groundwater samples across the Raichur district showed exceeding limits for parameters such as TDS, magnesium, fluoride, calcium, total alkalinity, total hardness, nitrate, and total arsenic content, making them unfit for drinking. This has led to the usage of water purification units with reverse osmosis candles in every household. In coming years, excess groundwater usage at this rate will lead to groundwater level depletion and ecological imbalance. The lakes have been distorted continuously and cannot be corrected naturally. Lake survival becomes desolate until and unless lake restoration, management, and conservation are taken up by both local administration and the residents. A public-private partnership model for the restoration of water quality and quantity, consisting of all the stakeholders, is urgent to stop the abandonment of lakes and prevent them from dying untimely. Diverse aspects of lake hydrology, chemistry, and geology to be investigated for sustainable management. The impact of pollution on water parameters and the ecosystem is the most abandoned research and needs to be initiated. Declarations Acknowledgments The authors thank Dr. Rajesh N L, Soil Science Dept, UAS, Raichur-584101, Karnataka, India, for the infrastructure facility. Funding The study was funded by Rashtriya Krishi Vikas Yojana (ABAC 6789-RKVY). Competing interests The authors declare that they have no competing interests. Ethics approval and consent to participate All authors have read, understood, and complied as applicable with the statement on the Ethical responsibilities of Authors. Consent for publication Not applicable. Author Contribution SP, MKG, TH have contributed to the experimentation and documentation. SNR has contributed to the conceptualization and writingVK, NMN have contributed to the heavy metal and microbial analysisPA has contributed the editing of the manuscript References Abbott, B. W., Bishop, K., Zarnetske, J. P., Hannah, D., Frei, R., Minaudo, C., & Pinay, G. (2019). A water cycle for the Anthropocene. Hydrological Processes , 33(23), 3046-3052. Aniyikaiye, T. E., Oluseyi, T., Odiyo, J. O., & Edokpayi, J. (2019). Physico-Chemical Analysis of Wastewater Discharge from Selected Paint Industries in Lagos, Nigeria. 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I., (2013).Variations in the physicochemical characteristics of the Buffalo River in the Eastern Cape Province of South Africa. Environmental Monitoring and Assessment, 185(10), 8733–8747. https://doi.org/10.1007/s10661-013-3208-1. Chowdhury, C. R., Shahnawaz, K., Kumari, D., Chowdhury, A., Bedi, R., Lynch, E., Harding, S., & Grootveld, M. (2016). Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects. Perspectives in Public Health , 136(6), 353–360. https://doi.org/10.1177/1757913915626744. Doneen, L. D. (1964). Notes on water quality in agriculture . Department of Water Science and Engineering, University of California, Davis. Foster, S. (1998). Groundwater: assessing vulnerability and promoting protection of a threatened resource. In Water-the key to socio-economic development and quality of life (Stockholm, 10-13 August 1998) (pp. 79-90). Foster, S. S. D. (1995). Groundwater for development: an overview of quality constraints. In Groundwater quality .17, 1-3. London: Chapman and Hall. Ganiger, S.V., (2014). Issues and Approaches to Rural Water Crisis in Karnataka: An Evaluation of Jal Nirmal Project. Global journal for research analysis , 3(1), 2277–8160. Haldar, K., Kujawa-Roeleveld, K., Hofstra, N., Datta, D.K. and Rijnaarts, H., 2022. Microbial contamination in surface water and potential health risks for peri-urban farmers of the Bengal delta. International journal of hygiene and environmental health , 244 , p.114002. Hem, J. D. (1985). Study and interpretation of the chemical characteristics of natural Water (Vol. 2254). Department of the Interior, US Geological Survey. Hokkanen, M., Luhtasela, U., Kostamo, P., Ritvanen, T., Peltonen, K., & Jestoi, M. (2018). Critical effects of smoking parameters on the levels of polycyclic aromatic hydrocarbons in traditionally smoked fish and meat products in Finland. Journal of Chemistry , 2018(1), 2160958. ISI. (1993). Indian standard specification for drinking water. ISI 10500, New Delhi. Jindal, M.R., & Wats, M. (2022). Evaluation of surface water quality using water quality indices (WQIs) in Lake Sukhna, Chandigarh, India. Applied water science 12(2).https://doi.org/10.1007/s13201-021-01534-x. Karanth, K.R., (1987). Groundwater assessment, development and management. Tata McGraw Hill publishing Company Limited, New Delhi. ISBN 0074517120, 9780074517123. Kishore, P., Singh, D. R., Chand, P., & Prakash, P. (2020). What determines groundwater depletion in India? A meso level panel analysis. Journal of Soil and Water Conservation , 19(4), 388-397.https://doi.org/10.5958/2455-7145.2020.00052.1. Kumar, R., Parvaze, S., Huda, M. B., & Allaie, S. P. (2022). The changing water quality of lakes—a case study of Dal Lake, Kashmir Valley. Environmental monitoring and assessment , 194(3), 228.https://doi.org/10.1007/s10661-022-09869-x. Kumar, S.K., Chandrasekar, N., Seralathan, P., Godson S.P., & Magesh, N.S. (2011). Hydrogeochemical study of shallow carbonate aquifers, Rameshwaram Island, India. Environmental Monitoring and Assessment, 184(7), 4127–4138. https://doi.org/10.1007/s10661-011-2249-6. Lipps, W.C., & Howland, E.B.B. (1995). Standard methods for the examination of Water and waste water , (19th ed). American Public Health Association, Washington, DC. Loizidou, M., & Kapetanios, E. G. (1993). Effect of leachate from landfills on underground water quality. The Science of the Total Environment , 128(1), 69–81. https://doi.org/10.1016/0048-9697(93)90180-E. Magesh, N. S., & Chandrasekar, N. (2011) Evaluation of spatial variations in groundwater quality by WQI and GIS technique: a case study of Virudunagar District, Tamil Nadu, India. Arabian Journal of Geosciences , 6(6) 1883-1898.https://doi.org/10.1007/s12517-011-0496-z. Manjushree, T. M., Joseph Sabu., & Thomas, Jobin. (2009). Hydrogeochemistry and groundwater quality in the coastal sandy clay aquifers of Alappuzha district, Kerala. Journal geological society of India, 74(4), 459- 468. https://doi.org/10.1007/s12594-009-0155-0. Puri, A., & Kumar, M. (2012). A review of permissible limits of drinking water. Indian Journal of Occupational and Environmental Medicine 16(1), 40-44. https://doi.org/10.4103/0019-5278.99696. Ramachandra, T.V., Sudarshan, P. B., Mahesh, M. K., & Vinay, S.(2018). Spatial patterns of heavy metal accumulation in sediments and macrophytes of Bellandur wetland, Bangalore, Journal of Environmental Management , 206, 1204-1210. https://doi.org/10.1016/j.jenvman.2017.10.014. Rohini, A. (2016). A brief overview on conservation of lakes in India. CVR Journal of Science and Technology, 11 , 106–110. Sawyer, C. N. and McCarty, P. L. (1967). Chemistry of sanitary engineers , (2nd ed). McGraw Hill, New York. https://doi.org/10.12691/ajwr-2-4-2. Sharma, R. C., & Kumar, R. (2017).Water quality assessment of sacred glacial Lake Satopanth of Garhwal Himalaya, India. Applied Water Science , 7(8), 4757–4764. https://doi.org/10.1007/s13201-017-0638-x. Additional Declarations No competing interests reported. Supplementary Files SupplementarydataRWater.docx 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-6166744","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":425559903,"identity":"89c692f1-11fb-4da8-aeb2-4d7f8ab4ffa5","order_by":0,"name":"Saroja Narsing 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03:53:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6166744/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6166744/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78272925,"identity":"cde8874c-8e53-4a93-a890-136a1a654800","added_by":"auto","created_at":"2025-03-11 13:42:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":131500,"visible":true,"origin":"","legend":"\u003cp\u003eSurface\u003cstrong\u003e \u003c/strong\u003eand groundwater sampling sites and zone classification in Raichur, Karnataka, India.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/38e8366799b82f800a0779c2.png"},{"id":78272217,"identity":"947993f1-34bc-444a-aa9f-2fab73c32278","added_by":"auto","created_at":"2025-03-11 13:26:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":326312,"visible":true,"origin":"","legend":"\u003cp\u003eFindings of pH and TDS in the municipality drinking water (blue), groundwater (red), and lake water (green) were collected from different locations in Raichur District.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/746dc686ab320999f227ad3f.png"},{"id":78272926,"identity":"c741da17-660e-499b-8e07-baf100121a4b","added_by":"auto","created_at":"2025-03-11 13:42:55","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":330737,"visible":true,"origin":"","legend":"\u003cp\u003eVariations in turbidity, alkalinity, and total hardness in the municipality water (blue), groundwater (red), and lake water (green) samples were collected from different locations in Raichur District.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/b1fa84e7830707be51906672.png"},{"id":78272499,"identity":"115cef09-d3ad-4f46-85f5-26a5e176d732","added_by":"auto","created_at":"2025-03-11 13:34:55","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":307581,"visible":true,"origin":"","legend":"\u003cp\u003eVariations in chloride and fluoride contents in municipality water (blue), groundwater (red), and lake water (green) were collected from different locations in the Raichur District.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/05e51be1e4de23ee14b5ee10.png"},{"id":78272927,"identity":"988a683c-7803-4aca-b968-cc22dc781b90","added_by":"auto","created_at":"2025-03-11 13:42:55","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":284771,"visible":true,"origin":"","legend":"\u003cp\u003eVariations in sulphate and nitrate concentrations in municipality water (blue), groundwater (red), and lake water (green) samples were collected from different locations in Raichur District.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/25cb981bcdaacb86db368eb1.png"},{"id":78272930,"identity":"f7fc8609-31c6-4ac4-81c6-3e0c8625bbde","added_by":"auto","created_at":"2025-03-11 13:42:55","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":275802,"visible":true,"origin":"","legend":"\u003cp\u003eVariation in calcium and magnesium in municipality water (blue), groundwater (red), and lake water (green) collected from different locations in Raichur District.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/49a387b83a3451b9635342df.png"},{"id":78272504,"identity":"3dda6106-49aa-4e2b-9d11-da0e4a8f3b8c","added_by":"auto","created_at":"2025-03-11 13:34:55","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":128205,"visible":true,"origin":"","legend":"\u003cp\u003eVariations in DO, BOD, and COD were determined from surface/lake water samples collected from various locations in the Raichur District.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/6352a6992a6fb1b9f7d4d9e7.png"},{"id":78272222,"identity":"6ac9301d-21c3-4e56-bcd8-e7efeb5a1ca1","added_by":"auto","created_at":"2025-03-11 13:26:55","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":57488,"visible":true,"origin":"","legend":"\u003cp\u003ePrincipal component analysis of physicochemical parameters determined for groundwater, surface water, and drinking water collected from the Raichur district.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/94a88c85b21e25c774f11a99.png"},{"id":79846142,"identity":"b47e48dd-9d2d-4f95-9585-a5c60ebe45b9","added_by":"auto","created_at":"2025-04-03 13:46:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2836943,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/e72b860a-e6f6-4648-a583-1fcf97f46e73.pdf"},{"id":78272220,"identity":"bdb9cc4d-e086-4d38-a119-2128dbc11b74","added_by":"auto","created_at":"2025-03-11 13:26:55","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":37200,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementarydataRWater.docx","url":"https://assets-eu.researchsquare.com/files/rs-6166744/v1/540269e5e15e6aed597186bf.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative quality assessment of the drinkability of abandoned lake water with ground and municipal water in Raichur, Karnataka, India","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIn the past, lakes in India served as primary sources for drinking, agriculture, and industry. Additionally, they serve as recharge zones for groundwater aquifers, flood cushions, and effluent absorbers. Numerous waterways have either disappeared or are currently in the process of disappearing. The primary cause is the extraction of lake water for real estate purposes in cities in India, including Hyderabad, Bangalore, and Ahmadabad. Despite the numerous lakes in these cities, survival is restricted (Ramachandra et al., 2018). In villages, cultivable land is used for setting up factories. Previously, the farmers utilized the lake silt as fertilizer, but now chemical fertilizers are used. Therefore, the silt is not removed but instead accumulates in the lakes. Increased urbanization and industrialization affect lake water quality deterioration across the Indian subcontinent.\u003c/p\u003e \u003cp\u003eThe degradation of lakes makes it unsafe to use Water for farming and drinking. UNICEF says that providing drinking water is still challenging in Asian countries, especially India, where 63\u0026nbsp;million people cannot access it (Hokkanen et al., 2018). Also, South Africa and other wealthy nations have terrible problems with having adequate fresh Water (Abbott et al., 2019). If nothing is done right away, two-thirds of the world's people will have trouble getting enough Water in the future (Aniyikaiye et al., 2019). Alternate to lake water, groundwater is an alternate source of drinking water in India, where approximately 251\u0026nbsp;billion cubic meters are used annually. Irrigated agriculture (60%) and drinking water stores (70\u0026ndash;85%) depend on groundwater. Six hundred million people are experiencing high to extreme water stress, with an estimated 2,000 people dying each year due to a shortage of access to drinking water (Puri \u0026amp; Kumar, 2012). The water quality index (WQI) ranks India 120th out of 122 countries. Food production is also at risk because many farmers struggle to cope with water resources efficiently. In recent decades, groundwater's excessive and mindless withdrawal has triggered a series of crises. Excessive drilling of bore wells and mechanized pumping has led to diminishing groundwater aquifers in many regions of the country, termed dark zones (Kishore et al., 2020).\u003c/p\u003e \u003cp\u003eWater quality analysis is frequently needed to assess surface and groundwater quality. The physicochemical properties of Kashmir Lake have led to a decline in quality due to a delay in quality restoring strategy (Kumar et al., 2022). An evaluation of artificial rain-fed Sukhan Lake in the Indian city of Chandigarh revealed that quality deterioration decreased from good to marginal, and regular monitoring of lake water quality was recommended (Jindal \u0026amp; Wats, 2022). The water quality of the sacred glacial-fed lakes in remote areas of the Himalayas has proven to be excellent and a good reference for other lakes in India (Sharma \u0026amp; Kumar, 2017). Analysis of contaminants in typical reservoirs on the Yellow River, China, to examine the geographical and temporal fluctuations in water quality (Loizidou \u0026amp; Kapetanios, 1993). They used the water quality index as a tool for the assessment. There is a report of anthropogenic causes that have a discernible impact on the groundwater quality around the coastal city of Tuticorin in southern India, as evidenced by the Water Quality Index (Manjushree et al., 2009).\u003c/p\u003e \u003cp\u003eThe study provided much-needed baseline data for reviewing issues related to water quality. In general, India's water systems are in a state of equilibrium, with the potential to either return to a sustained system or decline. In conclusion, the aquatic ecosystem in India is confronted with various threats, such as over-abstraction and river flow regulation, increasing pollution, encroachment, degradation of watersheds, and limited conservation efforts. Different methods have been established to evaluate water quality in numerous studies, such as multivariate statistical methods (Bear, 1979), modeling techniques (Doneen, 1964), and multi-metric index-based methods (Foster, 1995). Various researchers Karanth, 1987 \u0026amp; Kumar et al. 2011 have further developed the WQI, initially designed by Foster, 1998, and Hem, 1985. While there are formulas to figure out the WQI, they take a lot of different physical and chemical factors and turn them into a single number that shows the level of water quality. It removes the differences between the factors used separately in the assessment (Babiker et al., 2007).\u003c/p\u003e \u003cp\u003eThe Raichur district of Karnataka, India, is between two large rivers: Krishna on the northern border and Tungabhadra on the southern border. More than 95 of the sub-district's 171 villages are experiencing an extreme drinking water problem. People in Madagiri, Hallihosur, Gavittu, Haravi, Jakkaladinni, and Manvi towns are forced to drink fluoride-contaminated Water, which causes joint pain and fluorosis (Ganiger, 2014). In the same way, villages in the Devadurga sub-district have had the worst problem with drinking water since the drought in 1972\u0026ndash;73. The Krishna River has dried up for the first time in forty years. Depending on rivers, most villages and towns in Devadurga are having trouble getting clean Water (Chowdhury et al., 2016). To evaluate the abandoned lake water for its potability and to reduce the dependence on groundwater as a source of drinking water, a study was carried out primarily with the collection from various locations of Raichur and to analyze the microbiological and physicochemical characteristics according to the protocol of BIS.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eChemicals\u003c/h2\u003e \u003cp\u003eNIST traceable reference materials were purchased: fluoride (HC90463814), sulfate (HC90775013), nitrate (HC90701111), potassium dichromate (Merck-192403U), pH 4.0 (HC99926875), pH 7.0 (HC02254877) and pH 10.0 buffer solutions (HC97816109) were purchased from Merck, Bangalore, and calcium carbonate (192410M) and sodium carbonate (192405R) and sodium chloride (192406T ) from Supelco, Merck India. Class A glassware was used for the experiments. Lead, Cadmium, Mercury, Nickel, Total chromium, and Total Arsenic standards were purchased from Perkin Elmer, USA.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSample collection\u003c/h3\u003e\n\u003cp\u003eThe Raichur district is 454 km from Bengaluru and is 407 m above sea level. It is divided into five sub-districts for administrative purposes. In this study, we collected three sub-district samples for ground and surface water sampling. Groundwater samples from bore wells were used for dissolved oxygen (DO) determination, and the lake water was filled in glass bottles (250 ml) and added with Winkler's reagent in the site area. Eleven lakes named Usukuhanumappa, Neerbaavikunta, Aamthalab, Khakina, Jadarapete, Halepete, Nelhal, Dinni, Hunasihal, Sri Ram Nagar, and Rampur stations from June\u0026ndash;July 2024. Sampling was performed once during the study period between 11.00 am and 5.00 pm. The samples were taken from a point near the middle of the lake, and the sampling locations shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e were selected based on the agricultural activities in the vicinity and possible runoff into the river. The Raichur map and the location sites were created using ArcGIS version 10.2, Bangalore, India.\u003c/p\u003e\n\u003ch3\u003eAnalytical methods\u003c/h3\u003e\n\u003cp\u003eThe samples for determining the BOD were collected in 250 ml dark-colored bottles. The samples were analyzed using the American Public Health Association (Lipps and Howland, 1995) and Bureau of Indian Standards (BIS) 10500:2012 standard methods. The turbidity and pH were analyzed using pH and turbidity meters (HANNA HI 5221\u0026ndash;02) (HI 83414 turbidity meter and HI), and total dissolved solids (TDS) were measured via the gravimetric method (IS 3025 Part 16). The total hardness, calcium (Ca\u003csup\u003e2+\u003c/sup\u003e) content (IS 3025 Part 40), and magnesium (Mg\u003csup\u003e2+\u003c/sup\u003e) content (IS 3025 Part 46) were determined by titration method using a standard EDTA solution such as CaCO\u003csub\u003e3\u003c/sub\u003e (IS 3025 Part 21). Chloride (Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e) was determined via colorimetric titration using standard AgNO\u003csub\u003e3\u003c/sub\u003e (IS 3025 Part 32). The total alkalinity was estimated with sulfuric acid (0.02 N) (IS 3025 Part 23). The fluoride (F\u003csup\u003e-\u003c/sup\u003e) content via the APHA method, 23rd Edition 4500 D, the sulfate (SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e) content via the IS 3025 part 24, and the nitrate (NO\u003csup\u003e3-\u003c/sup\u003e) content via the IS 3025 part 34 were determined via a UV spectrophotometer. DO was determined via Winkler's procedure (APHA, 1998; part 4500 \u0026ndash; OC, p. 4-131), and the chemical and biological oxygen demands were determined via the APHA method. The methods taken from BIS and APHA were verified in the laboratory for linearity, precision, repeatability, and accuracy. The accuracy of the analyte was confirmed by recording the absorbance of the samples against the known concentration of the standards via a Perkin Elmer Lambda 365 N4100020 UV\u0026ndash;visible spectrophotometer. It was calibrated according to the USP43 (857) protocol. Enumeration of total coliform and \u003cem\u003eE. coli\u003c/em\u003e in surface water, drinking Water, and groundwater was carried out by the Most Probable Number (MPN) technique (IS 1622\u0026ndash;2019). The heavy metals were analyzed using ICP-MS (Perkin Elmer Nexion 350X) according to AOAC 2015.01 (20th edition 2016).\u003c/p\u003e\n\u003ch3\u003eAnalytical precision\u003c/h3\u003e\n\u003cp\u003eThe physicochemical data was analyzed through linear regression, ANOVA, Duncan multiple range test, and principal component analysis (PCA). The proficiency tests for parameters were conducted by National accredited testing agencies such as Global PT Provider Private Limited, New Delhi, and Aashvi Proficiency Testing and Analytical Services, Hyderabad, India, in the years 2022, 2023, and 2024 (supplementary data Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The measurement of uncertainty was calculated using the guidelines of Eurachem, 1989 (supplementary data Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eA total of 11 surface water samples, 16 groundwater samples from sub-districts of Raichur sites (Fig1), and five drinking water samples supplied from two different rivers, particularly the Narayanapur Reservoir of Krishna river right bank (15.754239ºN, 80.897270ºE) and the Tungabhadra River \u0026nbsp;(14°0′30″N 75°40′27″E) \u0026nbsp;to the residents of Raichur town were tested for water quality parameters and distinguished with the acceptable and permissible standards in accordance to Bureau of Indian Standards (BIS) Table 1.\u003c/p\u003e\u003cp\u003eThe physical, chemical, and organic factors that determine the quality of Water and keep it that way are all taken into account here. Different factors like TDS, pH, total hardness, alkalinity, Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e, Fl\u003csup\u003e\u0026minus;\u003c/sup\u003e, BOD, COD, DO, SO\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, Ca\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, Mg\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, and NO\u003csup\u003e3\u0026minus;\u003c/sup\u003e are measured and compared to the limits set by organizations like the CPCB, WHO, BIS, and others. Then, the changes in these parts are compared to the current standards set by the Bureau of Indian Standards (BIS) for drinking water quality (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\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\u003eAcceptable and permissible limits for drinking water quality characteristics by the Bureau of Indian Standards (BIS 10500:2012).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristic (mg/L)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAcceptable Limit\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePermissible Limit\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.5\u0026ndash;8.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal dissolved solids (TDS)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTurbidity, NT units\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcium (Ca\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChloride (Cl\u003csup\u003e-\u003c/sup\u003e )\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFluoride (F\u003csup\u003e-\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMagnesium (Mg\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNitrate (NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSulphate (SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e-2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal alkalinity (CaCO3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e600\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal hardness (CaCO3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e600\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFree residual chlorine (Cl\u003csub\u003e2\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChemical oxygen demand (COD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiological oxygen demand (BOD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e350\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDissolved oxygen (DO)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13\u0026ndash;14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e*Indicates no relaxation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003epH and TDS variation in lake, ground, and municipal water samples\u003c/h2\u003e \u003cp\u003eThe acceptable pH limit for drinking Water from any source ranges from 6.5 to 8.5. Our findings revealed that the groundwater samples collected from the Raichur city and sub-districts varied from 6.96 to 7.99 (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The lake water pH ranged between 7.63 and 8.8 units. Only one was above the acceptable limit. Among the 11 lakes, only Aamthalab (SW3) lake water had a pH of 8.8. This is caused by sewage disposal for more than 25 years and water draining from heavily fertiliser-fed nearby agricultural fields. The pH of the municipality-supplied drinking water also ranged from 7.11\u0026ndash;7.29, and no deviation from the acceptable range. The pH values of the GW, DW, and SW samples did not deviate much, as the values fell between the permissible limits of 6.5\u0026ndash;8.5 units, and none reached values above or below the limits.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe TDS of the groundwater samples in the Raichur district ranged from 330 mg/L to 8724 mg/L (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), meaning that most samples were higher than the maximum allowable level and could not be used for drinking. As stated in the BIS standard, the maximum level of TDS contaminants in drinking water is 500 mg/L, and it can be up to 2000 mg/L if no other source is available. However, the WHO says a TDS of up to 500 mg/L is the best level, and up to 1,500 mg/L is the most used.\u003c/p\u003e \u003cp\u003eGenerally, dissolved solids in any water source comprise inorganic salts and small amounts of organic matter. High TDS values of up to 8000 mg/L in groundwater account for natural resources, and the Raichur region is at the centre of the Deccan Plateau and features high salt content. The groundwater tends to contain high levels of dissolved solids, mainly high amounts of calcium and magnesium salts. Although high concentrations of dissolved solids are usually not a health hazard above 900\u0026ndash;1000 mg/L, limiting the Water becomes unacceptable and nonpalatable. Thus, out of the 16 GW samples analyzed for TDS, 14 samples had TDS concentrations greater than 1000 mg/L, which is highly above the acceptable limit for drinking. This finding indicates that 87.5% of the GW samples are not potable. Seventy-two percent of the lake water samples had TDS values less than 1000 mg/L, and 54.5% were below the acceptable limit and were all suitable for drinking purposes. The five lake water samples, i.e., Neerbavikunta (SW2), Aamthalab (SW3), Khakina (SW4), Jadarapete (SW5), and Halepete (SW6), are above 500 mg/L, which is more of a concern. It would be reasonable to know that they have high TDS values, as these lakes have been used as potable water for decades. The drinking water supplied by the municipality has three samples above the acceptable limit, and it becomes questionable whether such high TDS-containing water is provided to Raichur City and whether strict monitoring of Water for TDS is needed.\u003c/p\u003e \u003cp\u003e \u003cb\u003eVariation of turbidity, total hardness, and total alkalinity (CaCO\u003c/b\u003e \u003csub\u003e \u003cb\u003e3\u003c/b\u003e \u003c/sub\u003e \u003cb\u003e) in ground, surface, and drinking water.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe turbidity of the lake water reaches a range of up to 688 NT units (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e), which shows that the lake water across the district is highly turbid due to algae and other prokaryotes that grew as the water samples visibly had a green colour. In addition to being aesthetically unappealing, it is a significant health concern and provides food and shelter for pathogens. The turbidity of groundwater collected from the bore wells was less than one NT unit as expected, and in the case of drinking Water, it was less than 5 NT units. The total hardness of surface water varies from 77 to 401 mg/L, and 37.5% of groundwater samples are classified as hard (Sawyer \u0026amp; McCarty, 1967). Thus, 62% of the groundwater samples were moderately hard. In the case of surface water, 72% of the samples were soft, and 27% were moderately hard to completely hard, owing to the presence of alkaline ground elements such as calcium and magnesium. All the groundwater samples are above the acceptable limit, and 54% of the surface water samples are below the 200 mg/L concentration, which lies within the permissible limit (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Among the municipal drinking water supplies, two of the five samples had TDS concentrations greater than 200 mg/L, which is unacceptable for drinking. Thus, overall, surface water samples are better in the case of total alkalinity.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eChloride and fluoride variation in the contents of ground, surface, and drinking water\u003c/h3\u003e\n\u003cp\u003eChloride and fluoride levels in Raichur district sub-district GW, SW, and DW samples are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. SW chloride concentration ranged from 13.33 to 430 mg/L when BIS allowed 250 mg/L and 1000 mg/L. Neerbavikunta (SW2), Aamthalab (SW3), Jadarapete (SW5), and Halepete (SW6) lake samples are above the acceptable limit, but within 1000 mg/L. If the chloride concentration is above 250 mg/L, the Water tastes salty and would be unfit for irrigation (Chigor et al., 2013). The sustainability of agriculture and aquaculture is always in danger (Puri \u0026amp; Kumar, 2012). Only 50% of GW samples were \u0026lt;\u0026thinsp;250 mg/L. Two of the five drinking water samples had values above 250 mg/L, while three were below the limit. A high chloride level causes corrosion in plumbing pipe variations, as well as in water heaters.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eChloride in groundwater can originate from various causes, such as weathering, leaching of igneous rock and soil, salt carried by wind during precipitation, discharge of waste from homes and industries, municipal effluents, and other similar sources. The study region exhibits chloride values ranging from 12.01 to 539.87 mg/L, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The groundwater sample of the Sindhanur sub-district (GW13) contains a significantly high chloride content, and the ideal chloride limit for drinking water is 250 mg/L. Surplus chloride presence in groundwater is commonly used as a pointer of pollution and a tracer of contamination (Loizidou \u0026amp; Kapetanios, 1993). Surface water samples (SW2, SW3, SW5, and SW6) have Cl- concentrations of more than 250 mg/L, which substantially correlate with Na content and specific conductance (data not shown). The determination of chloride may be used to detect the interruption of water of varying compositions or to track and measure the volume of water mass movement. The fluoride parameter is subject to a 1.0 mg/L level set by the BIS, a prerequisite for approval. In the dearth of an alternative source, 1.5 mg/L is permissible. However, the fluoride levels in surface water samples were less than 1.0 mg/L, which is acceptable, and those in groundwater were 50% above the acceptable and permissible limits. Therefore, consuming such contaminated water is a health hazard. The drinking water supplied by the municipality is 20%, which is above the allowable limit.\u003c/p\u003e\n\u003ch3\u003eSulphate and nitrate content variation in ground, surface, and drinking water\u003c/h3\u003e\n\u003cp\u003eNatural waters contain sulphate as one of their primary anions. The sulphate concentration in potable Water is limited to 200 mg/L according to BIS 10500:2012. The sulphate concentrations in the ground, surface, and potable Water were 45.90\u0026ndash;440 mg/L, 15\u0026ndash;169 mg/L, and 14\u0026ndash;154 mg/L, respectively. The drinking and surface water samples had low to normal sulphate concentrations, and 37.5% of the GW samples had sulphate concentrations higher than usual. Thus, the concentrations of sulphate in all the sources of Waterfall are under the recommended limits of 200 mg/L (BIS) and 250 mg/L (250 mg/L) by the USEPA. The acceptable limit for nitrate concentration is 45 mg/L, and anything above is not given any relaxation. The nitrate contents of the GW, SW, and DW samples ranged from 0.5\u0026ndash;86 mg/L, 0.1\u0026ndash;5 mg/L, and 1.2\u0026ndash;19 mg/L, respectively. The nitrate concentration in the lakes of the primary Raichur district was 0.75\u0026ndash;1.6 mg/L (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e), with an average value of 0.76 mg/L, suggesting that the acceptable range contained all samples. Out of the 16 GW samples, only six presented nitrate contents above the permissible limit, and 10 were within the limit. Thus, groundwater must be treated via an ion exchange column to remove nitrate. All the drinking and surface water samples were safe for nitrate content.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eMagnesium and calcium ions variation in-ground, surface, and drinking water\u003c/h2\u003e \u003cp\u003eThe magnesium level is higher than the acceptable limit in 100% of the GW samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The readings were within the acceptable range in both the SW and DW samples. Calcium and magnesium levels are negatively correlated with human blood pressure, and the public is motivated to obtain information regarding the mineral composition of bottled or packaged water. The key to decreasing the calcium and magnesium ions leading to hardness is to use an ion exchange column or water softener device at the entrance point or within the households.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eMagnesium and calcium are the most profuse elements in natural soils, including surface and groundwater. They are found chiefly as bicarbonates and, to a lesser extent, sulphate and chloride. The Ca2\u0026thinsp;+\u0026thinsp;content ranges from 90 to 526 mg/L (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The relatively high Ca2\u0026thinsp;+\u0026thinsp;content in groundwater sample GW2 was 526.4 mg/L. Drinking water tests revealed that a few groundwater samples exceeded the allowable level. 62.5% of the groundwater samples collected from the sampling sites were above the maximum permissible limit of 200 mg/L for calcium, whereas 37.5% were below the legal range. Only two of the eleven surface water samples were above the allowable level, while the remaining samples were safe to drink. The high Ca2\u0026thinsp;+\u0026thinsp;content can cause gastrointestinal pain in adults and is unsuitable for residential use since it promotes scaling and crust formation in boilers/heaters. Magnesium concentration ranges from 1.4 to 106.4 mg/L. The maximum acceptable limits for Mg2\u0026thinsp;+\u0026thinsp;concentration in drinking water are 100 mg/L (ISI 1993) and 150 mg/L (WHO 2004). Every groundwater sample surpassed the magnesium content limit of 100 mg/L.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eCOD, BOD, and DO variations in surface water samples\u003c/h2\u003e \u003cp\u003eFor aerobic life forms, the water in these places does not look clean, but there is the presence of fish, indicating lakes are not contaminated with chemicals; natural stream cleaning systems need enough oxygen. It can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e that the COD of the surface water samples is less than 250 mg/L, and the BOD is below the acceptable level. The biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) show how wastewater has affected the ecosystem lake water of Aamthalab. Having enough dissolved oxygen in water is essential for maintaining the health of the lakes. Overall, the lakes are not polluted, and Raichur is less industrialized than the other Karnataka districts, especially Bangalore. The surface water had dissolved oxygen levels between 35 and 60 mg/L in subdistricts of Raichur, which is higher than the acceptable range of 6.5 to 8 mg/L.\u003c/p\u003e \u003cp\u003eAquatic organisms experience stress when the dissolved oxygen level in Waterfalls is below 5.0 mg/L. The tension increases as the concentration of the substance decreases. Consequently, dissolved oxygen levels below 1\u0026ndash;2 mg/L for a few hours can lead to the significant death of aquatic life, especially fish. The faecal coliform bacteria in the surface water samples suggested that the Water had been contaminated with faecal material (Data not shown). Other water-borne pathogens that cause typhoid fever, viral and bacterial gastroenteritis, and hepatitis A were identified (data are not presented).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePrincipal component analysis interpreted the information of a set of fourteen data parameters into information predicting the drinkability of drinking water, groundwater, and surface water samples. The top right side of Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows that the total hardness was high toward the non-permissible limit, especially in the groundwater samples (GW12, GW2, and GW6). This trend is also observed for TDS, which is more significant in the GW7, GW10, GW11, and GW16 samples. Similar samples formed a cluster, and the different samples were separated. The plot shows that surface water samples, especially SW2, SW3, SW4, SW5, and SW6, had turbidity levels toward the non-permissible limits. Similar results were demonstrated in dissolved oxygen and biological oxygen demand parameters. The remaining parameters, such as pH, turbidity, chloride, total hardness, calcium, magnesium, and total alkalinity, are near zero coordinates and are within the cluster. The total hardness and TDS were distinctly greater and central, reflecting parameters in groundwater than in drinking and surface water. Similar observations were found in the water quality Vishav stream of the Jhelum River of Kashmir Himalaya (Arafat et al., 2022).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eMicrobial and Heavy metal contaminants\u003c/h2\u003e \u003cp\u003eThe standard heavy metals of concern in lake water, drinking Water, and groundwater included lead, cadmium, arsenic, mercury, chromium, and nickel. The ICP-MS results (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) showed that the drinking and surface water samples did not show heavy metals exceeding the acceptable limit, whereas groundwater showed arsenic content from 0.01\u0026ndash;0.1 mg/L. Five of the 16 GW samples analyzed showed an arsenic content of 0.094 mg/L. The bacteriological quality of lake water samples showed 30\u0026ndash;210 total Coliform MPN/100 mL and 9\u0026ndash;88 \u003cem\u003eE.coli\u003c/em\u003e, whereas groundwater and drinking water had 0\u0026ndash;2 colonies (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which is not acceptable as per BIS specifications.\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\u003eHeavy metal concentration in the surface, ground, and drinking water Samples Lead Cadmium Mercury Nickel Total Chromium Total Arsenic (mg/L)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eSamples\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLead\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCadmium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMercury\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNickel\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTotal Chromium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eTotal Arsenic\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003e(mg/L)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.007\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.45\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDW1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDW2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDW3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDW4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDW5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\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\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparative bacteriological quality of surface water, groundwater, and drinking Water as per BIS 10500: 2012.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSamples\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal Coliform\u003c/p\u003e \u003cp\u003e(MPN/100 mL)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eE.coli\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(MPN/100 mL)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBIS requirements\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e210\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"12\" rowspan=\"13\"\u003e \u003cp\u003eShall not be detectable in any 100 mL sample\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e106\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e106\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e102\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e135\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSW11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e135\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e61\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW1-GW 16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u0026ndash;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u0026ndash;1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDW1 to DW5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u0026ndash;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\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\u003eIn the district of Raichur, India, the surface water of abandoned lakes has been dangerously altered or degraded at a more significant pace than their restoration. The total dissolved solids of the surface waters of Usukuhanumappa (SW1), Nelhal63 (SW7), Dinni 64 (SW8), Hunasihal 65 (SW9), Sri Ram Nagar66 (SW10) and Rampur 67 (SW11) are less than 500 mg/L, which is highly acceptable and accounts for 50% of the lakes that possess good physicochemical properties and are suitable for drinking purposes. The pH values of the surface waters of Usukuhanumappa (SW1), Neerbavikunta (SW2), Khakina (SW4), Jadarapete (SW5), Halepete (SW6), Hunasihal 65 (SW9), Sri Ram Nagar66 (SW10) and Rampur 67 (SW11) were in the acceptable range of 6.5\u0026ndash;8.5, and the pH values of the groundwater samples (GW1\u0026ndash;GW16) did not vary from the normal range. Twenty-five per cent of all the groundwater samples are above the permissible limit of 2000 mg/L, especially the Rampur (GW10), Askihal (GW11), Sharanama Bore (GW13), and K. Banadesh (GW16) samples. None of the groundwater samples were within an acceptable range. These findings match the lakes of Nagpur, India, where the National Environmental Engineering Research Institute (NEERI) certifies that 45% of the lake water is safe and suitable for drinking and that all the groundwater samples have TDS above the permissible level and are unfit for drinking. As water scarcity is an acute environmental problem, the focus is on improving existing water sources, particularly lakes, and employing quality determination for improvement and restoration (Magesh \u0026amp; Chandrasekar, 2011). The lack of use of lake water for drinking has often led to its deterioration apart from extreme pollution. These are made in lakes across Raichur city as cesspools.\u003c/p\u003e \u003cp\u003eConcerning turbidity, the abandoned lake water samples contained more than 9.38 NT units, a few of which included up to 688 NT units due to algal growth. Effective treatment is needed for all polluted lakes to ensure they become suitable for drinking. Coincidently, the groundwater does not have turbidity issues. The chloride content of the lake water ranged from 13.33\u0026ndash;430 mg/L, and 63% of the samples were above the permissible limits, and there was no discrepancy regarding the level. Slightly the water is salty and unpleasant to drink. The groundwater scenario is similar, as 50% of the samples are within the acceptable range and cannot be used for drinking.\u003c/p\u003e \u003cp\u003eThe chemical oxygen demand (COD) of the surface water samples collected across Raichur city was less than 1000 mg/L, indicating high pollution. This also suggests that spills, runoff, or sewage discharges contaminate surface water. Similarly, biochemical oxygen demand (BOD) is a commonly used index for determining water quality and indicates the overall concentration of organic substances. These results suggest that the decomposition of waste and bacteria and low quality resulted from values exceeding 5 mg/L. Water pollution is indicated by dissolved oxygen (DO) concentration less than 6.6\u0026ndash;8 mg/L. The water is suitable for consumption after a specific treatment when the concentration is less than 1000 mg/L. It is necessary to detect intermediate investigative action on \u003cem\u003eE. coli\u003c/em\u003e or total coliform bacteria. An even more precise indicator of faecal contamination is the presence of \u003cem\u003eE. coli.\u003c/em\u003e The current study indicated that the lake water of the Raichur district and its sub-districts Manvi, Deodurga, Lingasugur, and Sindhanur exhibited high pH and high alkalinity, while the other parameters were within the tolerance limits recommended by the World and ISI standards. The comprehensive assessment of water quality necessitates the evaluation of toxicological components, including heavy metals, apart from physical, chemical, and biological components.\u003c/p\u003e \u003cp\u003eMost groundwater samples contained fluoride concentrations ranging from 0.31 to 3.94 mg/L. Dental and skeletal fluorosis and passive bone fracture increase due to high fluoride levels. Surface water samples of the Raichur district had excellent fluoride concentrations lower than one mg/L (recommended value for drinking). The drinking water supplied to the southern Raichur district had one sample above 1.5 mg/L, making it unfit for drinking, whereas 75% of the groundwater samples in the Raichur district had fluoride values above one mg/L, indicating unsuitability for drinking. The variation in sulfate and nitrate contents in surface water was within the acceptable range and made it suitable for drinking, unlike in groundwater, where 37.5% are above the limits.\u003c/p\u003e \u003cp\u003eThe physical and chemical parameters for surface water are acceptable. However, the dissolved oxygen content was above the permissible limit. Thus, turbidity, color, DO, COD, BOD, or bacterial count do not affect surface water quality. If this Water has to be suitable for drinking, then possible pesticides and heavy metals must be checked for presence. The concentration of pollutants has increased due to the loss of water volume in lakes by encroachment in and around them. The government needs to clean the plants for the Water in the big lakes. So, water quality improves, and the public uses lake water as a primary drinking water source rather than groundwater. Monitoring the lakes will fetch small amounts of information, whereas the legal and administrative systems will take the right follow-up actions. The general public desires drinking water with minimum TDS and hardness. Softwater does not corrode and does not build up scales.\u003c/p\u003e \u003cp\u003eThe load of human dwellings along the lake shores has been recognized as the primary cause of environmental degeneration of the Aam thalab (Rohini et al. 2016). The Aam Thalab in Raichur is an example of one of the first Indian artificial lakes built around 1292 AD and the only drinking water source from 1960 to Raichur town. In the past sixty years, the urban population has increased, degrading the lake water quality beyond recovery. Encroachment, silting, weed infestation, extensive disposition of solid wastes by the population, and neglect by the district administration have made the lake into a dumping body for biological and chemical effluents (Chashoo et al., 2020).\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe load of human dwellings along the lake shores has been identified as the primary cause of environmental degeneration of the Aam Thalab Lake (Rohini, 2016). The Aam Thalab in Raichur is an example of one of the first Indian artificial lakes built around 1292 AD and the only drinking water source from 1960 to Raichur town. The urban population rise in the past sixty years has degraded the lake water quality beyond recovery. Encroachment, silting, weed infestation, extensive disposition of solid wastes by the population, and neglect by the district administration have transformed the lake into a dumping body for biological and chemical effluents (Chashoo et al., 2020). The water quality of the lakes of Raichur district has undergone gruesome anthropogenetic pressure for the last six decades. Over the years, turbidity, microbial load, dissolved oxygen, BOD, and COD concentration have increased enormously. The lakes have become hyper-eutrophic at several sites, severely affecting the lake ecosystem with no fish and other zooplankton. The remaining parameters, such as fluoride, chloride, alkalinity, pH, total dissolved solids, calcium, magnesium, and heavy metals, are within acceptable limits. Lake water can be treated and used for drinking, reducing our dependence on groundwater. Comparatively, the groundwater samples across the Raichur district showed exceeding limits for parameters such as TDS, magnesium, fluoride, calcium, total alkalinity, total hardness, nitrate, and total arsenic content, making them unfit for drinking. This has led to the usage of water purification units with reverse osmosis candles in every household. In coming years, excess groundwater usage at this rate will lead to groundwater level depletion and ecological imbalance. The lakes have been distorted continuously and cannot be corrected naturally. Lake survival becomes desolate until and unless lake restoration, management, and conservation are taken up by both local administration and the residents. A public-private partnership model for the restoration of water quality and quantity, consisting of all the stakeholders, is urgent to stop the abandonment of lakes and prevent them from dying untimely. Diverse aspects of lake hydrology, chemistry, and geology to be investigated for sustainable management. The impact of pollution on water parameters and the ecosystem is the most abandoned research and needs to be initiated.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank Dr. Rajesh N L, Soil Science Dept, UAS, Raichur-584101, Karnataka, India, for the infrastructure facility.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was funded by Rashtriya Krishi Vikas Yojana (ABAC 6789-RKVY).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have read, understood, and complied as applicable with the statement on the Ethical responsibilities of Authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eSP, MKG, TH have contributed to the experimentation and documentation. SNR has contributed to the conceptualization and writingVK, NMN have contributed to the heavy metal and microbial analysisPA has contributed the editing of the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAbbott, B. W., Bishop, K., Zarnetske, J. P., Hannah, D., Frei, R., Minaudo, C., \u0026amp; Pinay, G. (2019). A water cycle for the Anthropocene. \u003cem\u003eHydrological Processes\u003c/em\u003e, 33(23), 3046-3052.\u003c/li\u003e\n\u003cli\u003eAniyikaiye, T. E., Oluseyi, T., Odiyo, J. O., \u0026amp; Edokpayi, J. (2019). Physico-Chemical Analysis of Wastewater Discharge from Selected Paint Industries in Lagos, Nigeria. \u003cem\u003eInternational Journal of Environmental Research and Public Health,\u003c/em\u003e 16(7),1235. https://doi.org/10.3390/ijerph16071235\u003cu\u003e.\u003c/u\u003e\u003c/li\u003e\n\u003cli\u003eArafat, M. Y., Bakhtiyar, Y., Mir, Z. A., \u0026amp; Islam, S. T. (2022). 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McGraw Hill, New York. https://doi.org/10.12691/ajwr-2-4-2.\u003c/li\u003e\n\u003cli\u003eSharma, R. C., \u0026amp; Kumar, R. (2017).Water quality assessment of sacred glacial Lake Satopanth of Garhwal Himalaya, India. \u003cem\u003eApplied Water Science\u003c/em\u003e, 7(8), 4757\u0026ndash;4764. https://doi.org/10.1007/s13201-017-0638-x.\u003c/li\u003e\n\u003c/ol\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":"Water quality, acceptable limit, Physicochemical parameters, biplot, Heavy metals, microbial load","lastPublishedDoi":"10.21203/rs.3.rs-6166744/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6166744/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWater sources across India have become scarce, resulting in the consideration of ground and surface water as a single resource. Potable water quality from the surface or ground must comply with the national regulatory limits. Eleven abandoned lakes, sixteen grounds, and five drinking water samples in the Raichur district were analyzed.\u003c/p\u003e\n\u003cp\u003eOur findings of abandoned lake water included 14 physical-chemical parameters (mg/L): Total dissolved solids TDS(149.4–1298), Total hardness TH (77.31–401.31), Total alkalinity TA (89.44–430), Cl\u003csup\u003e−\u003c/sup\u003e (13.33–429.86), F\u003csup\u003e−\u003c/sup\u003e (0.16–0.89), Ca\u003csup\u003e2+\u003c/sup\u003e (26.98–121.03), Mg\u003csup\u003e2+\u003c/sup\u003e (12.23–68.1), SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2−\u003c/sup\u003e\u0026nbsp;(15.11–190.9), NO\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e (0.1–5.64), DO (38.3–60.12), COD (12.12–200.0), BOD (9.05–33.13) Free residual chlorine \u0026nbsp;FRC(\u0026lt;1 mg/L) and pH (7.09–8.8). Groundwater: TDS (330.0–8724), TH(6.2–1518), TA(10–587mg/L), Cl\u003csup\u003e−\u003c/sup\u003e (25.27–366.0), F\u003csup\u003e−\u003c/sup\u003e (0.31–3.94), Ca\u003csup\u003e2+\u003c/sup\u003e (1.6–527.0), Mg\u003csup\u003e2+\u003c/sup\u003e (1.12–241.0), SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2−\u003c/sup\u003e (7.56–440.0), NO\u003csup\u003e3-\u003c/sup\u003e(0.51–87.0)\u0026nbsp; FRC(\u0026lt;1) and pH (6.96–7.9).\u0026nbsp;Drinking water: TDS (36–891.67), TH(24.50–370.0), TA(18.89–340), Cl\u003csup\u003e−\u003c/sup\u003e (16.99–988.0), F\u003csup\u003e−\u003c/sup\u003e (0.09–1.83), Ca\u003csup\u003e2+\u003c/sup\u003e(12.83–136.8), Mg\u003csup\u003e2+\u003c/sup\u003e (2.83–56.59), SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2−\u003c/sup\u003e (8.1–170.78), NO\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e (3.1–19.82) FRC(\u0026lt;1–80), and pH (7.05–7.47). Ninety percent of the abandoned lake water samples met the acceptable limits for parameters TDS, TH, TA, pH, Cl\u003csup\u003e−\u003c/sup\u003e, F\u003csup\u003e−\u003c/sup\u003e, Ca\u003csup\u003e2+\u003c/sup\u003e, SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2−\u003c/sup\u003e, NO\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e, and Mg\u003csup\u003e2+\u003c/sup\u003e. The bacteriological quality of lake water samples showed coliform 30–210 total MPN/100 mL, and turbidity exceeded the acceptable limits (0–5 NTU). Sixty percent of the groundwater samples exceeded the permissible limits for TDS, 100% for magnesium, 75% for fluoride, 62.15% for calcium, and 40% for nitrate content. Five of the 16 groundwater samples analyzed for heavy metals showed an arsenic content of 0.094 mg/L. All the municipal water samples analyzed met the acceptable limits for physicochemical parameters and microbial load, indicating safe drinkability. This assessment outlines the future treatment needed for the restoration of abandoned lakes.\u003c/p\u003e","manuscriptTitle":"Comparative quality assessment of the drinkability of abandoned lake water with ground and municipal water in Raichur, Karnataka, India","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-11 13:26:50","doi":"10.21203/rs.3.rs-6166744/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":"a50d28a6-1c3c-4bc1-9afe-b9de12684471","owner":[],"postedDate":"March 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-04-03T13:38:30+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-11 13:26:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6166744","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6166744","identity":"rs-6166744","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}