Seasonal variation on physico-chemical parameters and trace metals in groundwater of an industrial area of north Chennai, India

Abstract

Seasonal variation on physico-chemical parameters and trace metals of groundwater in and around Ambattur industrial area, Chennai were determined. The hydrochemical investigation revealed that the seasonal effect does not change the order of abundance of cations and anions but it does change the concentration of various ions present in the groundwater. Alkali metals (Na + , K + ) and strong acids (Cl - , SO 4 2- ) are dominating over alkaline earth metals (Ca 2+ , Mg 2+ ) and weak acids (HCO 3 - , CO 3 2- ) for both seasons. Statistical analysis indicates the highest positive correlation exists between EC and Cl with correlation co-efficient of 0.97 and 0.96 during pre and post-monsoon respectively. Nitrate concentration in the groundwater ranges from 2 to 258 mg/l during pre-monsoon. in the case of post-monsoon, it ranges from 0 to 230 mg/L. During post-monsoon period, nitrate concentration decreased in many wells that are located mostly inside the industrial area. However, it has increased in the residential area, reflecting that the leaching of nitrate from the open sewerage lines. Groundwater in the study area is generally hard, fresh to brackish and low alkaline nature. The unsuitability of groundwater for drinking was identified in few places due to high total hardness and TDS. Fluoride is within the permissible limit for human consumption as per international standards.