Heavy Metals in Freshwater Fish along Pong and Chi Rivers(Thai)

Abstract

Certain trace metals in fish may lead to health problems through the food chain. This work aimed to study the accumulation of some heavy metals in freshwater fish along the Pong and Chi rivers. The fish were randomly sampled during late 2002 until early 2003 from 8 monitoring sites, marked A, B, C, D, E, F, G, H, located downstream between Ubolratana reservoir and Mahasarakham weir covering a river length of about 180 km. Cd, Co, Cr, Cu, Ni, Pb and Zn, were determined from samples of the muscle and adipose tissue of the fish by using atomic absorption. In comparison, the levels of heavy metals in the adipose were higher than those found in the muscle of the fish. The mean concentrations in these tissues were listed from high to low levels as follows: Zn > Cu > Cr > Co > Ni > Pb> Cd. Sites B and H showed high potential bioaccumulation of heavy metals in these fish during the highly contaminated season. Pollutant stress in fish should thus be emphasized with an establishment of future biomonitoring at potential contamination sites.