IMPACT OF HIGHWAY RUN OFF ON THE SURFACE AND GROUND WATER QUALITY IN THIRUCHIRAPALLI REGION, TAMIL NADU, INDIA

The runoff due to the pollutants caused by the road traffic significantly affects the receiving water bodies with high loads of particulate matter such as worn and torn out materials of automobiles, toxic substance like heavy metals, PCBs, salts such as chlorides and sulphates, and pathogenic bacteria. Our study assesses the impacts of highway/road run-off on the quality of adjacent drinking water sources. Water samples have been collected from 60 locations along the National Highways and other selected Metal Roads. The physico-chemical and biological parameters such as pH, Electrical Conductivity (EC), Chloride (Cl), Total Hardness (TH), Total Alkalinity (TA), Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Phosphate (PO4), Sulphate (SO4) and Nitrate (NO3), Total coliforms were assessed. The heavy metals such as Chromium (Cr), Copper (Cu), Zinc (Zn), Lead (Pb) and Arsenic (Ar) have been assessed randomly for 14 samples along the roads. The results show that pH , EC, TA , Nitrate and Total Coliforms are the major factors affecting the water quality. Cr levels exceed the permissible limits compared to the other metals. Our study shows that highway run-off may also be a potential source of ground water contamination along the urban periphery.