Heavy Metal Contamination of Water Bodies, Soils and Vegetables in Peri-Urban Areas: A Case Study in Bangaluru

Abstract

A study was conducted in peri-urban Bangaluru (where city wastewater from four water bodies, viz., Bellandur, Varthur, Byramangala and Nagavara tanks, is being used for cultivation of vegetable crops) to assess heavy metal contamination in water, soil and vegetable samples. Analyses revealed that concentration of cadmium (Cd) and chromium (Cr) in waters from all the tanks exceeded recommended levels of 0.01 and 0.1 mg/l, respectively, while content of lead (Pb) and nickel (Ni) are within safe limits. Concentration of Cd was highest in the water of Bellandur tank (0.039 mg/ l) and of Cr was highest in the water of Byramangala tank (0.311 mg/l). Bellandur and Varthur tanks were found highly contaminated with Cd, Pb and Ni. Mean concentration of heavy metals in soils receiving sewage water from the four tanks ranged from 1.92 to 2.9 mg/kg for Cd, 47.04 to 68.12 mg/kg for Pb, 35.08 to 92.78 mg/kg for Cr and 48.2 to 57.3 mg/kg for Ni. Cd and Pb content were highest in soils around Varthur and Bellandur tanks, while, mean concentration of Cr was highest in soils around Byramangala tank. Similar trends were observed for heavy metal content in vegetables. Among the vegetables studied, leafy vegetables accumulated higher concentration of heavy metals, followed by root vegetables. Cd concentration in all the vegetables grown around Varthur and Bellandur tanks exceeded the safe limit prescribed under Prevention of Food Adulteration Act (PFA 1954). Pb and Ni concentration exceeded safe limits in all the vegetables in all the tank areas studied.