Bioaccumulation Efficacy of Heavy Metals In Body Organs of Rainbow (Oncorhynchus Mykiss) and Brown (Salmo Trutta Fairo) Trouts of Gilgit-Baltistan

Abstract

Heavy metals are chemical elements that are poisonous and toxic comprising of both necessary and unnecessary trace metals. All aquatic organisms require very low amount of these metals yet in case where these values exceed to certain range, threshold harmful effects are levied upon the ecosystem. The aim of this study was to estimate the bioaccumulation of heavy and trace metals (Cr, Mn, Ni, Fe, Pb, Cu, Cd, Zn) in fish using Atomic Absorption Spectrophotometer (AAS). Samples of fish were procured from Ghizer and Astore districts of Gilgit-Baltistan region of Pakistan. The concentration of Cr, Pb, Cu and Cd were almost same and depicted low tendency of bioaccumulation as per WHO guidelines. The fish from Ghizer was having high concentration of Zn and Fe in intestine. While the concentration of Fe in muscles and intestine from the Astore species was slightly high. The highest concentration of Ni (10.09 ppm) was found in liver tissues of rainbow trout, while the lowest concentration (6.74 ppm) was in the fins of fish from Astore. In case of Cr, the highest concentration (3.8 ppm) was found in liver from both sampling sites, but the lowest concentration (0.24 ppm) was in the muscles of Ghizer Rainbow trout. The highest concentration of cu (6.09 ppm) was in the muscles of fish from Astore, but the lowest concentration (2.32 ppm) was found in many organs of fish from both study sites. Although the concentration of Zn, Mn and Fe were within the limits, however, the highest concentration of Pb (0.79 ppm) was in the muscles and the highest concentration of Cd (0.38 ppm) was in the skin of Ghizer rainbow trout. Concentration of Lead exceeded the limits of FAO/WHO in every organ of fish in both study areas, while all the other metals were in the maximum limits.