The effect of habitat on the accumulation of nickel (Ni) and cadmium (Cd) in the gastrointestinal tract of mullet

The aim of this study was to evaluate the effect of two different environments (Faroe Lake and Caspian Sea) on the accumulation of nickel and cadmium in gastrointestinal tissue. A total of 49 mullets collected and transported to the laboratory on Lake Faro and the Iranian shores of the Caspian Sea with ice. After extracting the contents of the gastrointestinal tract, the middle and near the end of the gastrointestinal tract were separated, digested and analyzed by ICP MS concentration of nickel and cadmium were measured by ICP MS. Environmental factors of the two regions were examined by multivariate analyzes. There was no significant difference in the concentrations of nickel and cadmium in the middle and near the end of the gastrointestinal tract, but the concentration of mentioned elements in Lake Faro were significantly lower than in the Caspian Sea. The principal component analysis of water parameters demonstrated that the variables were reducedto two components, which related 89. 72% of the total changes to temperature, salinity, dissolved oxygen and ph. Discriminate function analyses also explained 100% difference, which indicates the habitat differences between the two regions and demonstrated the effects of environmental conditions on the accumulation of nickel and cadmium as an indicator of environmental stress. Therefore, the results of this study can be used as a habitat assessment criterion and provide good information about environmental risk assessment.