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The unplanned Bhalswa landfill is located in one of the most urbanized area of Delhi, and its influence on the huge population are inevitable in the capital city of India lying in flood plain of the Yamuna River, and its alluvial lithology makes it more susceptible to contamination by leaching of pollutants. The present study highlights to assess the impact of non-engineered Bhalswa landfill site on the groundwater quality and associated potential health risk by its consumption to local residents of New Delhi, by collecting four leachate and sixty groundwater samples for pre- and post-monsoon seasons in the year 2013. The contamination potential of the leachate samples and the groundwater quality were evaluated with the help of leachate pollution index (LPI) and water quality index (WQI), respectively. The value of LPI is high in both the seasons but more in pre-monsoon (31.51) as compared to post-monsoon (29.36). The Obtained results of groundwater samples showed elevated level of Electrical conductivity (EC), major cations and anions. The EC of groundwater samples display concentration as follows: (pre-monsoon, 456–10870, average 3772; post-monsoon, 465–10450, average 3747). The groundwater samples close to the Bhalswa landfill shows very high value of EC and other chemical parameters. WQI calculated (using 17 physico-chemical parameters and WHO standards) to distinguish the areas of excellent and unsuitable for drinking purposes which will be helpful for the management of water resources. Our results showed that the concentration of majority of heavy metals exceed the WHO permissible limit except Cr and Cu which may be due to redox conditions that control the mobility of these ions in aqueous solutions. The average target hazard quotient (THQ) value of heavy metals were found in the order of Cd > Mn > Pb > Cu > Ni > Fe > Zn > Cr in both the seasons. The tube wells with more than one THQ value for Cd (100%), Mn (63%) and Pb (37%) will have potential human health risks. Hazard index (HI) shows greater than one value for all the samples and the average HI values are 10.241 for pre- and 10.402 for post-monsoon season. THQ and HI values suggest that the residents are highly susceptible to ingestion pathway. A conceptual model is used to describe the dispersal of leachate pollutants with reference to various kinds of geo-environmental features which degrades the groundwater quality. The health risk associated with metals in near future can be a serious threat for this region if this groundwater is being used for long run without proper remedial measures. [ABSTRACT FROM AUTHOR]

The area east of Varanasi is one of numerous places along the watershed of the Ganges River with groundwater concentrations of arsenic surpassing the maximum value of 10 parts per billion (ppb) recommended by the World Health Organization in drinking water. Here we apply geostatistics and compositional data analysis for the mapping of arsenic and iron to help in understanding the conditions leading to the occurrence of elevated level of arsenic in groundwater. The methodology allows for displaying concentrations of arsenic and iron as maps consistent with the limited information from 95 water wells across an area of approximately 210 km; visualization of the uncertainty associated with the sampling; and summary of the findings in the form of probability maps. For thousands of years, Varanasi has been on the erosional side in a meander of the river that is free of arsenic values above 10 ppb. Maps reveal two anomalies of high arsenic concentrations on the depositional side of the valley, which has started seeing urban development. The methodology using geostatistics combined with compositional data analysis is completely general, so this study could be used as a prototype for hydrochemistry mapping in other areas. [ABSTRACT FROM AUTHOR]

Fluorosis is becoming a global environmental toxicological problem and is most commonly found in water-stressed regions. In order to evaluate the geochemical mechanism of fluoride enrichment in groundwater and health implications in the Padwakodari environs of eastern part of India, a total of twenty two samples were collected and analysed for physico-chemical parameters spreading across the study area. Geologically, the area mainly comprises of phyllites, granite gneiss, mica schist and sandstone. High fluoride concentrations found mainly in the granite gneisses which are situated central to northwestern parts of the study area. The concentration of fluoride in the groundwater samples ranges from 0.3 to 11 mg/l with an average of 2 mg/l. 64% of the groundwater samples containing fluoride concentration that exceed the WHO drinking water guidelines value of 1.5 mg/l. Chronic ingestion of high doses has been linked to the development of dental fluorosis, and in extreme cases, skeletal fluorosis. The dominant geochemical facies present in water are Na–Ca–Mg–HCO 3 (11 samples), Na–Mg–Ca–HCO 3 (5 samples), Ca–Na–Mg–HCO 3 (5 samples) and Ca–Mg–Na–HCO 3 (1 sample). Sodium and bicarbonate ions being major component in majority of the water types (located mostly in the granite gneiss formation) has a tendency to increase fluoride concentration in groundwater by dissolving the fluoride from fluoride bearing minerals. The oversaturation of half of the samples with respect to calcite and majority of samples undersaturation with respect to fluorite makes it feasible for fluoride to get released in to the groundwater. Decreasing Ca activity downgradient (recharge to discharge) leads to a dominance of fluorite-unsaturated conditions and consequently to mobilization of fluoride in groundwater. The results indicate that the fluoride concentration in groundwater is mainly governed by high weathering of fluoride bearing minerals (i.e. apatite and biotite) in granite gneiss contains abundant fluoride, alkaline hydrogeological environment, high temperature, low rainfall, evapotranspiration and ion exchange. [ABSTRACT FROM AUTHOR]

Impact of arsenic (As) contaminated groundwater on human health, through drinking and irrigation practices, is of grave-concern worldwide. This paper present the review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water. Groundwater with high As concentration is detrimental to human health and incidents of As contamination in groundwater had been reported from different parts of the globe. More serious known As contamination problem as well as largest population at risk are found in Bangladesh, followed by West Bengal state in India along the Indo-Gangetic plains. Large scale natural As contamination of groundwater is found in two types of environment such as strongly reducing alluvial aquifers (ex. Bangladesh, India, China and Hungary) and inland basins in arid or semi-arid areas (ex. Argentina and Mexico). The provisional guideline of 10 ppb (0.0 l mg/l) has been adopted as the drinking water standard by World Health Organization (WHO). In the aquatic environment, the release, distribution and remobilization of As depend on temperature, redox potential, speciation, and interaction between liquid solution and solid phases. As predicaments in the environment is due to its mobilization under natural geogenic conditions as well as anthropogenic activities. Arsenic mineral is not present in As contaminated alluvial aquifer but As occurs adsorbed on hydrated ferric oxide (HFO) generally coat clastic grains derived from Himalayan mountains. As is released to the groundwater mainly by bio-remediated reductive dissolution of HFO with corresponding oxidation of organic matter. The development of strongly reductive dissolution of mineral oxides (Fe and Mn) at near-neutral pH may lead to desorption and ultimately release of As into the groundwater. As release through geochemical process is more important factor in alluvial aquifers causing As contamination rather than sources of arsenic. As is a toxin that dissolves in the bloodstream, rendering the victim susceptible to disease of the skin, bones, and also cancer of liver, kidney, gall bladder and the intestines. It is necessary to adopt highly successful technology to treat As contaminated water into the acceptable limit for human consumption. Universally accepted solutions are not developed/available even after the lapse of almost forty years since slow As poisoning identification in tens of millions of people especially in Bengal delta. The issue poses scientific, technical, health and societal problems even today. • Arsenic contaminated groundwater on human health is of grave concern worldwide. • Erosion, dissolution and weathering release arsenic to soil and water environment. • Arsenic is both a carcinogen as also a mutagen and toxicity of arsenic depends on its oxidation states. • Geochemistry and mobilization of arsenic is a complex phenomenon that affected by various biogeochemical processes. • Arsenic is toxin that dissolves in the bloodstream susceptible to skin/bone diseases and cancer of liver, kidney etc. [ABSTRACT FROM AUTHOR]

Around 9000 inhabitants in the Panda River basin, Sonbhadhra District, Uttar Pradesh, India, are vulnerable to a “silent” dental and skeletal fluorosis from groundwater consumption. The fluoride source and seasonal groundwater quality variation were studied by collecting 65 groundwater samples in the Upper Panda River basin. Major rock types are phyllites and granite gneissic rocks. Fluoride concentrations are in the range 0.4–5.6 mg/L in the pre-monsoon season and 0.1–6.7 mg/L in the post-monsoon season. Fluor-apatite and biotite mica in the granite gneissic rock were identified as the main provenance of fluoride in the groundwater through water–rock interactions. Due to precipitation of calcium, soils become alkaline with high contents of sodium; these conditions allow fluoride to accumulate in water. According to risk index calculations, the fluoride-affected villages were shown to fall in the fluoride risk zone (with a risk index of around 1.7). On the basis of mineral stability diagrams, groundwater from the weathered and fractured aquifers appears to be stable within the kaolinite field, suggesting weathering of silicate minerals. The groundwater is chemically potable and suitable for domestic and agricultural purposes, except for a few wells in the southern region that are contaminated with high amounts of fluoride. Editor D. Koutsoyiannis Citation Raju, N.J., Dey, S., Gossel, W., and Wycisk, P., 2012. Fluoride hazard and assessment of groundwater quality in the semi-arid Upper Panda River basin, Sonbhadra District, Uttar Pradesh, India. Hydrological Sciences Journal, 57 (7), 1433–1452. [ABSTRACT FROM AUTHOR]

Fluoride (F¯) concentration over and above the permissible limits (1.5 mg/l) in drinking water leads to human health hazards, such as dental and skeletal fluorosis affecting millions of people in many parts of India. Preliminary investigations indicate that severe health disorders have been identified in parts of the Kachnarwa region, which is in the upper Panda river basin, Sonbhadra District, Uttar Pradesh, due to excess intake of fluoride through drinking water. The lithological units of the study area mainly consist of granite and gneissic complex rocks of the Chota-Nagpur Plateau. In order to understand the probable source of fluoride and its concentration, 17 groundwater samples mostly from granite and phyllite regions were collected for fluoride estimation during May 2006. The concentration of fluoride in the groundwater of the study area varies from 0.483 to 6.7 mg/l. Among the 17 samples analysed, 8 exceeded the maximum permissible limits of fluoride in the study area. The source of fluoride in the groundwater of the study area is mainly from geological occurrence (i.e. fluoridebearing minerals, viz. apatite and biotitic mica). Microscopic analysis of the rock samples showed 5-10% apatite and 20-25% biotite, but other fluoride-bearing minerals like fluorite and hornblende were characteristically absent. X-ray diffraction studies showed that apatite mineral peak profile of the rock samples corroborated with the fluorapatite of the standard set by the JCPDS. The worst fluoride-affected villages are Rohiniyadamar, Madhuri, Neruiyadamar, Gobardaha and Kunrwa. Most people in these villages suffer from dental and skeletal fluorosis such as mottling of teeth, deformation of ligaments, bending of spinal column and ageing problem. An urgent need is to educate the people on the causes of fluorosis, encouraging rainwater harvesting and providing fluoride-free drinking water in the study area. [ABSTRACT FROM AUTHOR]

Borehole data reveals that during Late Quaternary, the Ganga river was non-existent in its present location near Varanasi. Instead, it was flowing further south towards peripheral craton. Himalayan derived grey micaceous sands were being carried by southward flowing rivers beyond the present day water divide of Ganga and mixed with pink arkosic sand brought by northward flowing peninsular rivers. Subsequently, the Ganga shifted to its present position and got incised. Near Varanasi, the Ganga river is flowing along a NW-SE tectonic lineament. The migration of Ganga river is believed to have been in response to basin expansion caused due to Himalayan tectonics during Middle Pleistocene times. Multi-storied sand bodies generated as a result of channel migration provide excellent aquifers confined by a thick zone of muddy sediments near the surface. Good quality potable water is available at various levels below about 70m depth in sandy aquifers. Craton derived gravelly coarseto-medium grained sand forms the main aquifer zones of tens of meter thickness with enormous yield. In contrast, the shallow aquifers made up of recycled interfluve silt and sandy silt occur under unconfined conditions and show water-level fluctuation of a few meters during pre- and postmonsoon periods. [ABSTRACT FROM AUTHOR]

In order to establish season-wise relationship between total dissolved solids (TDS), electrical conductance (EC) and silica (SiO2) in upper Gunjaneru River basin, Kadapa district, Andhra Pradesh, a study has been made by collecting 51 and 46 groundwater samples during post-monsoon and pre-monsoon season, respectively. TDS, EC and silica are some of the groundwater quality parameters measured in a laboratory generally. EC and silica measurements are made quickly and are less costly than TDS measurement. The results indicate that 99.7% and 99.8% of the variability in TDS could be ascribed to the variable EC and SiO2 concentrations and the rest by some other unaccounted variables in the post-monsoon and pre-monsoon season, respectively. Inclusion of SiO2 concentration in the regression models produces, for individual samples, a lower per cent difference between measured and estimated TDS for both seasons. However, on the average the inclusion of SiO2 in regression models reduced the mean difference 0.09% for the post-monsoon season and 0.11% for the pre-monsoon. From regression analysis it is found that the multiple regression model did not improve the predictability of TDS values over the linear regression model for both post-monsoon and pre-monsoon seasons. TDS can be estimated from either EC or EC and SiO2 by these regression models within the acceptable limit of error. This is due to the low content of SiO2 in the groundwater samples in shale aquifers of the study area. [ABSTRACT FROM AUTHOR]

Correlations and multiple linear regressions were used to develop models relating well water chemical quality parameters to a set of independent chemical variables in post- and pre-monsoon seasons in the upper Gunjanaeru River basin, Cuddapah district, Andhra Pradesh, South India. The correlation between the specific electrical conductance (SEC) and other parameters except potassium (K+) is significantly positive, whereas Ca2+ + Mg2+/Na+ + K+ is significantly negative for both post- and pre-monsoon seasons. In predicting SEC for both post- and pre-monsoon, the independent variables, viz. HCO3-, SO42- and Cl- in the model had a significant effect (from 't' test for partial regression coefficient at the 5% level of probability). The multiple R² values 0.982 and 0.997 indicate that 98.2 and 99.7% of variability in the observed SEC could be ascribed to the combined effect of Na+, Cl-, Ca2+ + Mg2+, HCO3-, and SO42- for post- and pre-monsoon seasons, respectively. Out of the 98.2% variability in SEC due to the combined effect of Na+, Ca2+ + Mg2+, HCO3-, SO42- and Cl-; 44.8% is due to HCO3-, 44.4% is due to Cl-, 9% is due to SO42- and 2% each is due to Na+ and Ca2+ + Mg2+ for post-monsoon season. Whereas in the pre-monsoon season, 99.7% variability in SEC is due to the combined effect of Na+, Ca2+ + Mg2+, HCO3-, SO42- and Cl-; 38.8% is due to Cl-, 36.9% is due to HCO3-, 12% is due to Na+, 7% is due to SO42- and 3% is due to Ca2+ + Mg2+. This shows that HCO3-, Cl-, SO42- and Cl-, HCO3-, Na+, SO42- are the most significant independent variables in predicting SEC for post- and pre-monsoon seasons respectively. [ABSTRACT FROM AUTHOR]

'Blue carbon' has recently seized the attention of the scientific communities as they are believed to provide the benefits of climate change mitigation given its high potential to store carbon under unfavourable conditions. Keeping in mind the importance of the carbon storage capacity of mangroves, the present study has been carried out to determine the sedimentary organic carbon stock in Coringa mangroves. The value of total organic carbon (TOC) ranges from 0.63 to 2.76% with a mean value of 1.30±4.3%. The value of total nitrogen (TN) varies from 0.04 to 0.19% with an average value of 0.08±0.03%. Dry Bulk Density (DBD) ranges from 0.63 to 2.58 gm cm-3 with a mean value of 1.33±0.19 gm cm-3. The mean value of sedimentary carbon stock (SCS) in Coringa mangrove is 158±32.60 Mg C ha-1. This amounts to the below-ground sedimentary carbon stock being 1.86 Tg C and represents the equivalent CO2 emission of 579.9 Mg CO2e ha-1. The TOC, TN, DBD, and SCS show significant spatial variation among the different sites. The maximum carbon stock is found in densely vegetated Coringa mangroves, followed by moderately vegetated Gaderu mangroves and the least is found in the degraded forest of Matlapalem mangroves. Grain size parameters signify that there is no definite relationship between the organic carbon content and the abundance of finer sediments fractions in the Coringa mangrove. The higher carbon stock in Coringa mangroves reveals their importance in storing carbon and hence could have relevance on a national scale too and play an important role in climate change mitigation [ABSTRACT FROM AUTHOR]

A small ephemeral Swarnamukhi River (hard rock) basin, more sensitive to climate change, was sampled and analyzed for various parameters. A total of 66 river water samples (22 of each season) were collected from different sampling stations covering the whole Swarnamukhi River basin in pre- and post- and monsoon seasons. Chemical weathering rate data of the Swarnamukhi River basin is integrated with the available data of other large perennial (Godavari and Krishna) and ephemeral (Kaveri and Periyar) hard rock river basins of Peninsular India. The Peninsular river basins, including Swarnamukhi River basin, are mainly dominated by granitic gneissic terrain. Contribution of inputs through forward modelling shows: silicate > evaporite > carbonate > atmosphere. The mean silicate and carbonate weathering rates in the river basin observed are 27.15 tonnes.km−2.yr−1 and 9.45 tonnes.km−2.yr−1 in pre-monsoon season, whereas 32.73 tonnes.km−2.yr−1and 45.90 tonnes.km−2.yr−1 in post-monsoon season, respectively. The Swarnamukhi river has lower silicate weathering rate (annual average: 30.57 tonnes.km−2.yr−1) than other published river basins data (Narmada: 33.9 tonnes.km−2.yr−1; Nethravati: 42 tonnes.km−2.yr−1; Godavari: 45.6 tonnes.km−2.yr−1) due to different localized geological setting. Mean annual CO 2 consumption for the Swarnamukhi River is 6.9 × 105 mol km−2.yr−1 which is comparable to other Peninsular rivers such as the Godavari (6 × 105 mol km−2.yr−1) and Gad (5.7 × 105 mol km−2.yr−1) rivers. The study further provides the inventory for CO 2 consumption on river basin scale, which is an important consideration from the global warming point of view. • Forward model employed to calculate different sources of major ion contribution by chemical weathering. • Comparison of mean CO 2 consumption rate depicts silicate weathering is dominating. • Chemical weathering rates and CO 2 consumption rate used to compare results with global point of view. [ABSTRACT FROM AUTHOR]

In situ experiments were conducted to determine the net ecosystem production (NEP) in cryoconite holes from the surface of two glaciers (Patsio glacier and Chhota Shigri glacier) in the Western Himalaya during the melt season from August to September 2019. The study aimed to gain an insight into the factors controlling microbial activity on glacier surfaces in this region. A wide range of parameters, including sediment thickness, TOC %, TN %, chlorophyll-a concentration, altitudinal position, and grain size of the cryoconite mineral particles were considered as potential controlling factors. From redundancy analysis, the rate of Respiration observed in cryoconite at Chhota Shigri glacier was predominantly explained by sediment thickness in cryoconite holes (37.1% of the total variance, p < 0.05) with Photosynthesis largely explained by the chlorophyll-a content of the sediment (39.6%, p < 0.05). NEP was explained primarily by the TOC content and sediment thickness in cryoconite holes (35.8% and 22.1% respectively, p < 0.05). The altitudinal position of the cryoconite is strongly correlated with biological activity, suggesting that the stability of cryoconite holes was an important factor driving primary productivity and respiration rate on the surface of Chhota Shigri glacier. We calculated that the number of melt seasons required to accumulate organic carbon in thin sediment layers (< 0.3 cm), based on our measured NEP rates, ranged from 11 to 70 years, indicating that the organic carbon in cryoconite holes largely derives from allochthonous inputs, such as elsewhere on the glacier surface. Phototrophic biomass in the same thin sediment layer of cryoconite was estimated to take atleast 4 months to be produced in situ (with mean estimated time upto 1.7 ± 1.5 years). Organic matter accumulated inside the cryoconite holes both through allochthonous deposition and via biological activity on the glacier surface in these areas may have the potential to export dissolved organic matter and associated nutrients to downstream ecosystems. Given the importance of Himalayan glaciers as a vital water source for millions of people downstream, this study highlights the need for further investigation in aspects of the quantification of in situ produced organic matter and its impact on supraglacial melting in the Himalaya. [ABSTRACT FROM AUTHOR]

Delineation of Glaciers is a challenging task in the Himalaya due to its complex topography, cloud cover, seasonal snow cover, hillshade, debris cover. Glacio-hydrological studies including mass balance, run-off, and dynamic modelling rely on the availability of consistent and reliable glacier inventory datasets. This article on data set presents a homogenous, multidecadal inventory of glaciers in the Chandra-Bhaga Basin (CB Basin), western Himalaya, for 1993, 2000, 2010, and 2019. Landsat Thematic Mapper (TM), Enhanced Thematic mapper (ETM+), and Operational Land Imager (OLI) imageries, with minimum snow and cloud cover have been used for enhanced accuracy and consistency. Uncertainty assessment for the generated glacier inventory was performed, following various approaches such as buffer method, standard error estimation, and manual digitisation error and the maximum uncertainty has been quantified. We have identified and manually mapped a total of 251 glaciers with an area > 0.5 km², and in order to minimise the uncertainty, field surveys were carried out on 6 glaciers in the basin. Out of these 251 glaciers, 217 are clean ice and 35 were debris-covered glaciers. The estimated total glacier area was 996 ± 62 km² in 1993 that decreased to 973 ± 70 km² in 2019. Apart from quantifying temporal changes in glacier area, this inventory further allows the estimation of supraglacial debris cover and glacier volume. The supraglacial debris cover area has increased by 14.1 ± 2.54 km² (15.2 %) during 1993-2019. Accuracy of the debris cover dataset estimated using ground surveys is 82 % with a kappa coefficient of 0.87. Moreover, a glacier ice volume dataset was also generated by incorporating the inventory into Glacier Bed Topography Version 2 (GlabTop2) model and shows a total of 112.5 ± 41 km³ of ice volume stored in the CB Basin glaciers. For accuracy assessment of the DEMs generated using ASTER Stereopairs images, DGPS surveys were carried out on (28 GCPs) and off (6 GCPs) the glaciers. Glacier volume uncertainty with respect to the generated DEMs and model bias is 5.3 km³ and 35.5 km³ respectively. Overestimation of glacier volume due to over deepening is estimated to be 1.2 km³. The impact of climate change on the Himalayan glaciers is a matter of serious concern and such holistic multitemporal inventory datasets can help quantify that impact with improved certainty. [ABSTRACT FROM AUTHOR]

The present study aims at the assessment of environmental quality of the most polluted stretch of river Yamuna along the megacity of Delhi. The study was conducted in order to examine toxicity and health hazards associated with persistent pollutants present in the fluvial ecosystem. Eighty four sediment and 56 vegetable samples from same locations were collected from the Delhi segment of river Yamuna flood plain in order to examine 20 organochlorine pesticides (OCPs) and 9 heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Both the organic and inorganic groups of persistent toxic substances were monitored and analysed for the extent of eco-toxicological as well as dietary health risks posed to the local population. Eco-toxicological assessment was done based on sediment quality guidelines, enrichment factor, geo-accumulation index, degree of contamination and Pollution Load Index. The dietary-risk was assessed with the help of translocation factors (TF) of these pollutants in vegetables. Carcinogenic and non-carcinogenic health risks from consumption of vegetables were also investigated. The level of concern for heavy metals was greater than that of OCPs as per the sediment quality guidelines. DDT, Cd, Pb and Zn had maximum concentrations corresponding to level 3 of concern, while Cr and Ni reached up to the highest i.e., 4th level of concern. Sediment samples were found to be enriched and contaminated significantly with Cd and moderately with Pb, as represented respectively by enrichment factors and contamination factors (CF). CF for metals lied in order Zn > Cd > Cr Ni > Pb Cu. Pollution load index was highest at the location lying on the exit point of Yamuna in Delhi. TF values greater than 1 were observed in majority of samples analysed for Ni, Cr, Cu and Zn. Spinach topped among vegetables in terms of metal contamination. Cd, Ni and Pb accumulated more in the roots, as against Mn, Zn, Cu and Cr which had higher accumulation in the shoots. Translocation factors were substantially high in vegetables for most of the OCPs, clearly indicating bioaccumulation and potential health risk to the consumers. Health risk to humans was assessed for non-carcinogenic and carcinogenic potentials from ingestion of vegetables. Hazard Quotient (HQ) > 1 due to radish (roots and leaves) and cauliflower consumption in children indicated non-carcinogenic risk. Hazard Index (HI) beyond 1 for all the vegetables (except onion leaves) confirmed substantial cumulative risk. Lifetime cancer risk (LCR) revealed moderate (spinach, radish, beet root and cauliflower) to low (all the others) levels of carcinogenic risk to humans. Cancer risks from γ-HCH, β- HCH, Hept, Hept Ep, Ald, p,p'-DDT, and Cr exposure through the food chain could be well established. [Display omitted] • 20 OCPs and 9 heavy metals were studied in fluvial ecosystem of river Yamuna. • OCPs and heavy metals in sediment and vegetables exceeded freshwater sediment quality guidelines. • Metals showed high enrichment and contamination factors, geo-accumulation and pollution load indices. • High translocation factors in vegetables indicated bioaccumulation in the food chain. • Vegetable consumption carried potential non-carcinogenic and carcinogenic risks, especially in children. [ABSTRACT FROM AUTHOR]

• Godavari geothermal province is manifested with several geothermal waters with issuing surface temperature 30–55 °C and near neutral nature (pH: 6.5–7.3). • The investigation suggests a moderate enthalpy geothermal system. • The heat flow value observed in geothermal wells ranges from 83 to 388 mW/m2 which provide geothermal gradient range 22.5–105.5 °C/km in Manuguru area. • This research suggest that the Manuguru area can produce 3584 MW e using Organic Rankin Cycle (ORC). The Godavari geothermal field in India is one of the potential areas manifested by several geothermal waters and groundwaters. The geothermal waters of the area are near neutral (pH: 6.5–7.3) with surface temperature ranging from 30 to 55 °C while groundwaters are also near neutral (pH: 6.6–7.5) with surface temperature ranging from 24 to 28 °C. The hydrogeochemistry of the geothermal waters suggests that the geothermal waters show a Na-Ca-SO 4 -HCO 3 to a Ca-HCO 3 type and groundwaters are of the Ca-HCO 3 to Na-Ca-HCO 3 type while groundwaters and river waters are of the Ca-Na-SO 4 types. The geothermal waters of the study area are enriched in SO 4 2– and Cl–, due to the interaction with the pyrite-bearing Gondwana sediments and granitic gneiss basement rocks. Furthermore, enrichment of Ca2+, Mg2+ and an increased HCO 3 /Cl ratio in geothermal water is caused by the exchange and/or mixing process that takes place during water-rock interaction at an elevated temperature while ascending to the surface. This type of behavior of water is also observed during the water-rock interaction experiment at 100 °C. Studies on geothermal gas geochemistry suggest the deeper circulation of geothermal waters in the crust and high helium concentration as a thermal gas that can be utilized for commercial purposes. Estimated reservoir temperatures from quartz and Na-K-Ca geothermometry are in the range 110–195 °C. Therefore, the geothermal water of the study area is categorized as a moderate enthalpy geothermal system. Thermal logging in the borewell and depth range from 50 to 1000 m suggest that the geothermal gradient in the Manuguru area ranges from 22.5 to 105.5 °C/km and heat flow ranges from 83 to 388 mW/m2, which is higher than the regional condition. Therefore, 3584 MW e power can be produced by using the Organic Rankine Cycle (ORC) from the Manuguru geothermal area of Godavari valley. [ABSTRACT FROM AUTHOR]