Geochemical evaluation of groundwater around Chromepet tannery belt, Southern India

Abstract

The study appraises the geogenic and anthropogenic contamination of groundwater around tanneries located in Chromepet, Southern India. Thirty-six groundwater samples were examined for major anions, cations and trace metals concentration. The concentration of chromium (Cr), iron (Fe) and lead (Pb) in the study area ranges from 0.04 to 0.51 mg/L, 0.001–1.07 mg/L and 0.001–0.09 mg/L respectively. 97% of the samples exceeded the acceptable range for Cr whereas, lead and iron exceeded 89 and 8% of the samples respectively. The high concentrations of chromium, iron and lead in the groundwater are due to the influence of tannery effluents. The majority of the samples in the study area suggested silicate weathering. The piper plot reveals that 50% of the water samples have Na–Cl type water which is possibly due to anthropogenic sources. The Chadha plot revealed that silicate weathering and ion exchange govern the bulk of groundwater chemistry in freshwater aquifers owing to carbonate precipitation and mineral dissolution. Durov plot highlights that the bulk of the samples has no dominating anion or cation types, indicating simple dissolution or mixing. Saturation Index (SI) reveals that 50% of the samples were supersaturated due to calcite and dolomite precipitation. Principal Component Analysis (PCA) 1 suggested secondary salt discharge from geogenic and anthropogenic processes due to tanning industries. Increasing the performance of wastewater treatment plants is essential to improve the groundwater quality of the region under tannery influence.