Source identification and management of perennial contaminated groundwater seepage in the highly industrial watershed, south India.

Perennial contaminated groundwater seepage is threatening the downstream ecosystem of the Kazipally Pharmaceutical industrial area located in South India. The sources of seepage are unknown for the last three decades that challenging the regulatory authorities and industries. In general, water quality monitoring and geophysical techniques are applied to identify the sources. However, these techniques may lead to ambiguous results and fail to identify the seepage sources, especially when the area is urbanized/paved, and groundwater is already contaminated with other leakage sources that have similar chemical compounds. In the present study, a novel and multidisciplinary approach were adopted that includes satellite-based Land Surface Temperature (LST) observations, field-based Electrical Resistivity Tomography (ERT), continuous Soil Electrical Conductivity (SEC) and Volumetric Soil Moisture (VSM%) measurements along with groundwater levels monitoring to identify the sources and to control the seepage. The integrated results identified that the locations with the Standard Thermal Anomaly (STA) in the range of -0.5 to -1 °C, VSM% >50%, SEC > 1.5 mS/cm, bulk resistivity < 12 Ω m with shallow groundwater levels < 3 m below ground level (bgl) are potentially contaminated perennial seepage sources. Impermeable sheet piles have been installed across the groundwater flow direction to control the seepage up to 1.5 m bgl, where groundwater frequently intercepts land surface. The quantity of dry season groundwater seepage has been declined by 79.2% after these interventions, which in turn minimized the treatment cost of 1,96,283 USD/year and improved the downstream ecosystem.

Groundwater chemistry integrating the pollution index of groundwater and evaluation of potential human health risk: A case study from hard rock terrain of south India.

Groundwater is an important resource for drinking and irrigation purposes and also the significant route of human exposure in most of the arid and semi-arid regions of the world. In view of this, 43 groundwater samples were collected and analyzed for various physico-chemical parameters. Particularly, this study integrates the groundwater contamination by comparing it to national guidelines and the impact of fluoride and nitrate on health risk were quantified through the model recommended by the United States Environmental Protection Agency (USEPA). The groundwater of the investigated region is slightly alkaline in nature with hydrochemical facies of groundwater is predominantly characterized by Ca2+-Mg2+-HCO3- and Ca2+-Mg2+-Cl- water types. The results show that the concentrations of groundwater nitrate and fluoride range from 2.2 to 165 mg/L and 0.84 to 4.3 mg/L, and 55.81% and 65% of groundwater exceed the national guidelines for drinking purposes, respectively. The pollution index of the groundwater (PIG) method unveiled that low quality and moderate quality of water account for 40% and 4.65% of collected groundwater samples, respectively. The results of non-carcinogenic health risk ranged from 0.63 to 5.31 ± 2.59 for adults, 0.85 to 7.18 ± 3.50 for children and 0.98 to 8.29 ± 4.04 for infants, indicating health risk was higher in infants and children as compared to the adults in the study region.

Potentially toxic elements (PTEs) pollution in surface soils in a typical urban region of south India: An application of health risk assessment and distribution pattern.

The pollution level of potentially toxic elements (PTEs) in surface soils is detrimental to the ecosystem and human health. In this research, various indices such as an index of geo-accumulation (Igeo), contamination factor (CF), degree of contamination (DC), and principal component analysis (PCA) were implemented to identify and evaluate the soil PTEs pollution; and then human health risk assessment model used to establish the link between heavy metals pollution and human health in the urban region of south India. Results exhibited that the mean concentration of Cr, Cu, Ni and Zn were found to be 1.45-6.03 times greater than the geochemical background values. Cr and Cu were the most profuse PTEs measured in the soils. The pollution indices suggest that soil of the study region is mainly moderate to highly polluted. The non-carcinogenic health risk assessment proposed by the United States Environmental Protection Agency (USEPA) suggested the mean hazard indices (HIs) were below one which denotes no significant of non-carcinogenic risks to both children and adults. Furthermore, carcinogenic risk assessment results advised ~80% of cancer risk was caused by Cr contents, while other heavy metals indicate that neither children nor adults in the study region were of carcinogenic risks.