Annual variation of selected trace etals in freshwater lake fish,Abeo Rohita,as an index of nvironmental pollution

Annual variations in the concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg in fish Labeo rohita from Rawal Lake, Pakistan, are reported. The results are reported on mean annual basis, along with statistical parameters such as variance, standard deviation, skewness and kurtosis. Mathematical correlation coefficients between pairs of metals are reported at significant level of r = 0.468 (p = 0.000). Maximum concentration was found in the case of Zn (4.807 μg/g, wet weight) and the minimum for Cd (0.003 μg/g, wet weight). Some spurious concentration episodes for Ni, Cr, Cu and As were identified and explained in terms of probable anthropogenic sources. The study revealed that fish alone could not be used as a sole index of environmental pollution and there was a need to include the sediment‐water link to this effect.