Keywords: heavy metals, water pollution, Halali reservoir, drinking water, chromium, nickel, effluents, impact assessment, waste disposal, water quality, freshwater reservoirs, India, physico–chemical parameters
Impact assessment of waste disposal on water quality of a freshwater reservoir of India
Physico–chemical parameters and heavy metals were analysed in water samples, collected during rainy, winter and summer season of 2006–2007 to evaluate the impact of wastes on Halali reservoir. In surface water temperature, pH, TDS, EC, free CO2, DO, alkalinity, hardness and chloride were from 18.3–35.5°C, 7.4–8.9, 103–509 mg L−1, 162–800 µS cm−1, 0–14.86 mg L−1, 5.27–9.93 mg L−1, 65–256 mg L−1, 81–294 mg L−1 and 18.66–97.89 mg L−1, respectively for different seasons, while in bottom water the respective values were from 15.2–28.9°C, 6.8–8.5,105–517 mg L−1, 166–803 µS cm−1, 0–12.73 mg L−1, 4.39–7.92 mg L−1, 65–208 mg L−1, 92–296 mg L−1 and 25.4–93.47 mg L−1. Cd, Cr, Cu, Ni, Pb and Zn were 1.1–1.98 µg L−1, 1.46–21.26, 1.12–17.76, 1.12–18.24, 6.14–27.2 and 4.76–61.84 µg L−1 for surface water, and 1.3–3.74 µg L−1, 16.94–263, 10.44–28.76, 2.56–27.14, 9.44–53.24 and 19.54–112 µg L−1 for bottom water. All the studied water quality parameters varied with depth and seasons. Barring a few exceptions for TDS, the values of physico–chemical parameters were within the maximum permissible standard values prescribed for drinking water by Bureau of Indian Standards (BIS) and World Health Organization (WHO). However, there is a strong possibility of Cr and Ni pollution in Halali reservoir due to their higher concentration in reservoirs water and hence necessary measures may be taken to prevent their entry into the food chain.