Heavy Metals in the Blood Serum and Feces of Mugger Crocodile ( Crocodylus palustris ) in Sistan and Baluchistan Province, Iran

This study was conducted to measure concentrations of cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), copper (Cu), chromium (Cr), and iron (Fe) in blood serum and feces of mugger crocodile ( Crocodylus palustris ) and in water and sediment of their habitat (Negour site, Chabahar County in Sistan and Baluchistan Province, Iran). Heavy metal contents in crocodile serum and feces, water, and sediments were analyzed by inductively coupled plasma optical emission spectrometry (ICP–OES spectrometer—Spectro Genesis). The highest levels of heavy metals in the mugger crocodile’s serum were Fe > Hg > Pb > Cr > Cu > Cd > As, respectively. The total metal concentrations in the feces exhibited the following decreasing order from Fe > As > Pb = Cr > Hg > Cd > Cu. The highest average levels of heavy metals in water were Hg > Fe > As > Pb > Cu > Cr > Cd respectively and As > Fe > Pb > Cu > Hg > Cd > Cr in the sediment of lagoons. A significant difference was observed in the concentration of Fe and Pb between male and female crocodiles. Moreover, correlation analysis indicated significant negative correlations between sex and bioconcentrations of Cd, Fe, Pb, As, and Hg in the serum. In conclusion, this study showed that the environmental conditions of Negour lagoons are not suitable for crocodiles regarding habitat health and water quality. Furthermore, since these lagoons and fish are the most important sources of drinking water and seafood for the residents of the area, contamination of these pools with heavy metals can also threaten people’s health.