Bioaccumulation of heavy metals in relation to body length of Oreochromis mossambicus

Abstract

The nature of the relationship between bioaccumulation of heavy metals and body size (length) in Oreochromis mossambicus from Beira Lake and Weras Ganga in the Colombo District of Sri Lanka was inverstigated. The work was carried out during March - July 1995. The organs; muscle, gills, gonad, kidney and liver were investigated. Analysis was done by the x-ray fluorescence method. There was a significant difference (p0.05) in the metal levels in a paricular organ between the different length classes. A positive ans statistically significant correlation with body length was seen for Cu concentration in the kidney in both the Beira Lake and Weras Ganga samples. A significant positive correlation with body length was observed for Zn in the gill and kidney, and for Fe in the muscle and liver, of the Beria LAke sample. For Cd in the muscle, a significant negative correlation with length was observed in the Beria Lake sample. This is noteworthy since the muscle is the tissue that is normally consumed. In the same site there was also accumulation of lead in one of the smaller size classes.