Translocation and bioaccumulation of trace metals from industrial effluent to locally grown vegetables and assessment of human health risk in Bangladesh

Abstract

In this study, we evaluated the level of trace metals in the soil of heavily loaded tannery and battery industry area on the bank of the Buriganga River, Dhaka, Bangladesh in order to investigate their translocation to the locally grown vegetables and potential health risk of the local consumers. Concentrations of various metals in agricultural soil and in a number of vegetables such as; Red amaranth (Amaranthus cruentus), Spinach (Spanacia oleracea), Jute leaf (Corchorus capsularies), Bottle Gourd (Lagenaria siceraria), Mustard green (Brassica juncea) and Water spinach (Impomoea aquatica) were determined by atomic absorption spectrometry. The content of chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in the soil was around 500, 50, 50, 40, 0.8 and 200 mg/kg, respectively. Cr and Pb were found in the locally grown vegetables around 20 and 0.5 mg/kg respectively, which are higher than the permissible limit of them (2 mg/kg for Cr and 0.3 mg/kg for Pb) in vegetables as recommended by FAO/WHO and the data confirm the translocation of the metals from the soil to the vegetables. Hazard index value of all the vegetables considered was above 1, which indicates that the people could experience severe health risk due to consumption of any of those vegetables. Total cancer risk (TCR) value was obtained for Cr, Ni and Pb content in the local vegetables and it was observed that the value was around 1 × 10−3 for all of the sample vegetables. The high TCR values (higher than the USEPA threshold level of 1 × 10−6) indicate that there is a potential cancer risk due to intake of vegetables grown in that area.