Heavy Metal Content in Fish of the Barguzin River (Eastern Cisbaikalia) and Assessment of Potential Risks to Human Health

In this paper, the levels of nine heavy metals in the organs and tissues of six commercially important fish species from the Barguzin River (Eastern Cisbaikalia, Russia), bream Abramis brama, roach Rutilus rutilus, crucian carp Carassius carassius, common carp Cyprinus carpio, perch Perca fluviatilis and northern pike Esox lucius, were investigated. The distribution of HMs in the fish organs and tissues was unequal and was determined by both their physiological functions and routes of entry. The study also characterized the environmental habitats, including water and sediments, and conducted an assessment of potential risks to human health associated with fish consumption. The results showed that the levels of Fe, Zn, Cu, Ni, Cd, Pb, Cr and Hg in the muscle tissue of fish from the Barguzin River were generally low and did not exceed the maximum allowable concentrations established in Russia and worldwide. However, Mn levels in a number of samples exceeded the corresponding maximum allowable concentrations, which may be attributed to its elevated presence in the habitat. The calculated fish condition factor K showed good health status of fish from the Barguzin River. The highest Metal Pollution Index values were recorded for northern pike scales (5.9), which, however, corresponded to a low level of contamination. The other metal pollution index values for fish organs and tissues were all below five, indicating either no or very low contamination. Risk to human health was assessed using target hazard quotients and hazard index. None of these indices, both for each fish species studied and for each of the nine heavy metals, exceeded one. This indicated that consumption of the fish species studied did not pose an excessive risk of non-carcinogenic health effects to humans. The data on the content of nine heavy metals in the main commercially caught fish species from the Barguzin River indicated a low level of tissue and organ contamination by heavy metals and the absence of health risks to humans associated with their consumption as food.