Lead concentration increase in the hepatic and gill soluble fractions of European chub (Squalius cephalus) - an indicator of increased Pb exposure from the river water

Purpose was to examine if chronic exposure of feral fish to elevated Pb concentrations in the river water (up to 1 μg L-1), which are still lower than European recommendations for dissolved Pb in surface waters (7.2 μg L-1 ; EPCEU 2008), would result in Pb accumulation in selected fish tissues. Lead concentrations were determined by use of HR ICP-MS in the gill and hepatic soluble fractions of European chub (Squalius cephalus) caught in the Sutla River (Croatia-Slovenia). At the site with increased dissolved Pb in the river water soluble gill Pb levels (17.3 μg L-1) were approximately 20 times higher compared to uncontaminated sites (0.85 μg L-1), whereas the ratio between contaminated (18.1 μg L-1) and uncontaminated sites (1.17 μg L-1) was lower for liver (15.5). Physiological variability of basal Pb concentrations in soluble gill and hepatic fractions associated to fish size, condition, sex or age was not observed, excluding the possibility that Pb increase in chub tissues at contaminated site could be the consequence of studied biotic parameters. However, in both tissues of Pb-exposed specimens, females accumulated somewhat more Pb than males, making female chubs potentially more susceptible to possible toxic effects. The fact that Pb increase in gill and hepatic soluble fractions of the European chub was not caused by biotic factors and was spatially restricted to one site with increased dissolved Pb concentration in the river water points to the applicability of this parameter as early indicator of Pb exposure in monitoring of natural waters