Evaluation of groundwater quality and human health risks from fluoride and nitrate in semi-arid region of northern India.

Groundwater quality in the alluvial plains of Punjab has special significance and needs great attention since it is the foremost source of drinking, irrigation and industrial uses. The present research work emphasizes the integrated hydrogeochemical and chemometric statistical approaches to appraise the geochemical processes and source apportionment of the groundwater in the alluvial plains of Jalandhar district, Punjab, India. The human health risk assessment was also performed to quantify the potential non-carcinogenic impacts of nitrate and fluoride on human health through ingestion of groundwater. For this purpose, 41 groundwater samples were collected from different groundwater abstraction units and analysed for pH, electrical conductivity, total dissolved solids, total hardness, total alkalinity and major ions (Ca2+, Mg2+, Na+, K+, HCO3-, CO32-, SO42-, NO3-, F-, Cl- and PO43-) using standard protocols. Drinking water quality index and Revelle index showed that groundwater samples fall under poor to unfit water class and salinization along the south-western portion of the study region shows poor water quality. The results of the hazard index (HIingestion) show 68% and 46.34% of the groundwater samples have HI > 1 for children and adults. The non-carcinogenic health risk assessment of nitrate (NO3-) and fluoride (F-) on the local population indicated that the children are more vulnerable through direct ingestion of drinking water than adults. Piper diagram and saturation index reveal that Ca2+-Mg2+-HCO3- is the dominant hydrochemical facies and oversaturated with calcite, dolomite and aragonite minerals in the groundwater. Gibbs diagrams, chloro-alkaline indices and scatter plots show that the hydrochemistry of the groundwater is mainly governed by aquifer material interaction such as weathering of silicate, carbonate rock, halite dissolution and cation exchange process. Chemometric statistical techniques revealed that the source identification of parameters such as Ca2+, Mg2+, Na+, K+, HCO3-, CO3- and F- is originated from geogenic factors, whereas NO3-, SO42-, Cl- and PO43- are from the anthropogenic origin. Therefore, urgent and efficient measures must be taken to combat groundwater pollution and reduce human health risk in the study area.

Ecological and human health risk assessment of pharmaceutical compounds in the Sirsa River of Indian Himalayas.

The Baddi-Barotiwala-Nalagarh (BBN) region of Indian Himalayas is one of the most important pharmaceutical industrial clusters in Asia. This study investigated the distribution, and ecological and human health risks of four most frequently used pharmaceuticals [ciprofloxacin (CIP), norfloxacin (NOR), cetirizine (CTZ) and citalopram oxalate (ECP)] when co-occurring with metal ions in the Sirsa river water of the BBN region. The concentration range of the selected pharmaceuticals was between 'not detected' to 50 µgL-1 with some exception for CIP (50-100 µgL-1) and CTZ (100-150 µgL-1) in locations directly receiving wastewater discharges. A significant correlation was found between the occurrences of NOR and Al (r2 = 0.65; p = 0.01), and CTZ and K (r2 = 0.50; p = 0.01) and Mg (r2 = 0.50; p = 0.01). A high-level ecological risk [risk quotient (RQ) > 1] was observed for algae from all the pharmaceuticals. A medium-level risk (RQ = 0.01-0.1) was observed for Daphnia from CIP, NOR and ECP, and a high-level risk from CTZ. A low-level risk was observed for fishes from CIP and NOR, whereas CTZ and ECP posed a high-level risk to fishes. The overall risk to ecological receptors was in the order: CTZ > CIP > ECP > NOR. Samples from the river locations receiving water from municipal drains or situated near landfill and pharmaceutical factories exhibited RQ > 1 for all pharmaceuticals. The average hazard quotient (HQ) values for the compounds followed the order: CTZ (0.18) > ECP (0.15) > NOR (0.001) > CIP (0.0003) for children (0-6 years); ECP (0.49) > CTZ (0.29) > NOR (0.005) > CIP (0.001) for children (7-17 years), and ECP (0.34) > CTZ (0.21) > NOR (0.007) > CIP (0.001) for adults (>17 years). The calculated risk values did not readily confirm the status of water as safe or unsafe because the values of predicted no-effect concentration (PNEC) would depend on various other environmental factors such as quality of the toxicity data, and species sensitivity and distribution, which warrants further research.

Probabilistic modelling is superior to deterministic approaches in the human health risk assessment: an example from a tribal stretch in central India.

This case drew national attention in 2018. About 100 people died and more than 300 hospitalized in a span of few years in a village of 1200 people in a tribal stretch in central India. Medical teams visiting the area reported severe renal failure and blamed the local eating and drinking habits as causative factors. This human health assessment based on geochemical investigations finds nitrate (NO3-) and fluoride (F-) pollution as well in village's groundwater. Both deterministic and probabilistic techniques are employed to decipher the contamination pathways and extent of contamination. Source apportionments of NO3- and F- and their relationship with other ions in groundwater are carried out through chemometric modelling. Latent factors controlling the hydrogeochemistry of groundwater too are explored. While hazard quotients ([Formula: see text]) of the chemical parameters ([Formula: see text] and [Formula: see text]) identify ingestion as the prominent pathway, the calculated risk certainty levels (RCL) of the hazard index (HI) values above unity are compared between the deterministic and probabilistic approaches. Deterministic model overestimates the HI values and magnify the contamination problems. Probabilistic model gives realistic results that stand at infants ([Formula: see text] = 34.03%, [Formula: see text] = 24.17%) > children ([Formula: see text] = 23.01%, [Formula: see text] = 10.56%) > teens ([Formula: see text] = 13.17%, [Formula: see text] = 2.00%) > adults ([Formula: see text] = 11.62%, [Formula: see text] = 1.25%). Geochemically, about 90% of the samples are controlled by rock-water interaction with Ca2+-Mg2+-HCO3- (~ 56%) as the dominant hydrochemical facies. Chemometric modelling confirms Ca2+, Mg2+, HCO3-, F-, and SO42- to originate from geogenic sources, Cl- and NO3- from anthropogenic inputs and Na+ and K+ from mixed factors. The area needs treated groundwater for human consumption.