Bioaccumulation of Cr, Ni, Cd and Pb in the Economically Important Freshwater Fish Schizothorax plagiostomus from Three Rivers of Malakand Division, Pakistan: Risk Assessment for Human Health.

Contamination of freshwater ecosystems such as rivers with hazardous heavy metals is an environmental problem of public health concern. Accumulation of potentially toxic heavy metals in freshwater fish causes a potential health threat to their consumers including humans. The present research aimed to (1) investigate the accumulation of four potentially toxic heavy metals viz. Cr, Ni, Cd and Pb in muscle tissue of the commercially important freshwater fish Schizothorax plagiostomus at different sites of River Swat, River Panjkora and River Barandu in northern Pakistan (2) to compare gross metal accumulation in the fish samples by calculating metal pollution index (MPI) and (3) to assess potential risk to the health of the fish consumers. Samples were analyzed for the heavy metals by flame atomic absorption spectrophotometry (FAAS). Risk analysis showed that Ni risk was higher at River Panjkora and River Barandu, Pb risk was higher at River Swat and River Panjkora while Cd risk was quite low at all the three rivers.