干旱区生态环境知识资源中心

A qualitative approach, including geochemical and multivariate statistical approaches, is applied to evaluate the groundwater quality and human health risk, based on analytical data of 72 samples collected from a semi-arid region of eastern Maharashtra, India. The shifting of hydrochemical type from Ca2+-Na+-HCO3- to Na+-Ca2+-Cl- type was observed along different flow paths. The main controlling processes observed from the chemical characterisation of the groundwater are water-rock interactions, dedolomitisation and reverse ion exchange. Simulation analysis (mass transfer) exposes the dissolution of dolomite, gypsum, halite, k-feldspar and CO2 down the simulated pathways. Around 77% of the total variance was observed from the first three principal component analyses. The high positive loadings of EC, TDS, Na+, K+, Ca2+, Cl-, NO3- and SO42-of PC1 revealed silicate weathering and reverse ion exchange followed by human activities as the contamination sources. The sources identified for high positive loadings on HCO3- and SO42-of PC2 are soil CO2 and human activities. The high loadings of pH and F- in PC3 revealed fluorite dissolution and calcite precipitation. The human health risk calculated for NO3- revealed that 58% and 44% of the total groundwater samples surpassed the tolerance limit for non-carcinogenic risk of 1.0 in children and adults. The human health risk assessment for fluoride showed high hazard index values in 40% and 23% of the total groundwater samples for children and adults, respectively. The study suggests some management measures for protection of groundwater resources.