Levels of toxic metals in edible fish species of the Tigris River (Turkey); Threat to public health

Abstract

Tigris River has international importance as it runs through the borders of three countries. The levels and probable public health risks of heavy metals (Mn, Cd, Fe, Cu, Ni, Zn, Co, Pb, Cr, As) in 72 muscle and gill samples out of six fish species in Tigris River, Turkey were determined then compared with results of prior studies. Furthermore, human health risk levels from fish consumption were assessed using multiple approaches. The mean maximum heavy metal levels in the muscles were as follow; 175.88 > 22.34 > 10.29 > 2.81 > 2.76 > 1.68 > 0.33 > 0.25 > 0.05 = 0.05 mg kg−1 for Fe > Zn > Mn > Cu > Ni > Cr > Pb > As > Cd = Co, respectively. The highest muscle tissue levels for 8 heavy metals out of 10 measured were found in C. macrostomus species. The mean max. levels of Cu and Pb, the remaining two heavy metals, were measured in muscle tissue of L. abu species. The mean maximum concentrations of heavy metals of Cr, Cu, and Zn in all fish samples were below the maximum permissible limits (MPLs). The carcinogenic risk (CR) values for Pb, Cr, Ni and As were calculated and evaluated respectively in all of the Tigris River's fish species. While CR values calculated for Pb in all species did not pose a risk, it was found above the threshold value of 10−4 for some fish species for Cr, Ni and As. Target hazard quotients (THQs) from metal intake by consuming fish species were below 1 for all heavy metals which indicated no hazard from consumption. In addition, since the hazard index (HI) is lower than “1″, it has been concluded that the consumption of fish species will not pose a potential health risk. Considering by CR values exclusively, the results disclosed that the intake of the analyzed fish species might cause a toxicological hazard and impend to community health.