Environmental pathway and risk assessment studies of the Musi River's heavy metal contamination - A case study

The Musi River, in Hyderabad, the capital city of Andhra Pradesh state in India, is relatively dry for most of the year except for the four monsoon months when 700-800 mm of rain falls. Throughout the year, sewage, industrial, and hospital waste is released into the fiver. In the present work the Musi River from Amberpet Bridge to Nallacheruvu (8 km stretch) was assessed and monitored for heavy metal contamination attributable to sewage and industrial effluents. Twelve locations were assessed for Zn, Cr, Cu, Ni, Co, As, Hg, Cd, and Pb in soils, waters, forage grass, milk, and vegetables. A sequential extraction scheme revealed that high levels of Zn, Cr, and Cu were associated with labile fractions, making them more mobile and phytoavailable. Human risk was assessed in people exposed to pollution by analyzing metals concentrations in venous blood and urine. Results showed high amounts of Pb, Zn, Cr, and Ni compared to permissible limits, attributable to the consumption of contaminated food. Metals concentrations were monitored systematically to assess risks and support management decisions to help curtail the possible entry of metals into human food chains. An assessment was also made of a possible analysis of a remediation technology for lead-contaminated soils and water.