Bioavailability of Pb, Sb, Cu and Zn in a rifle-range runoff: Accumulation and biomarker response in Brown trout (Salmo trutta L)

Abstract

The present knowledge on environmental effects on aquatic biota caused by heavy metal efflux from rifle ranges is insufficient in order to predict the effects on the ecosystem. The goal of this work has been to provide data on speciation of lead (Pb), antimony (Sb), copper (Cu) and zinc (Zn) in a rifle range runoff, and to document accumulation and toxic interactions of theses metals in fish. We found that the efflux of Pb and Cu differed significantly during a snow melting event, while Sb and Zn did not. Dissolved heavy metals caused acute and evident osmoregulatoric dysfunction in juvenile trout exposed to the shooting range effluent. Contrary to our hypotheses, correlations between cationic heavy metals in the low molecular mass fraction (<10 kDa) and accumulation of heavy metals in fish liver and gills were weak or absent, even when Ca and pH were taken into consideration. Accumulation of Sb in fish gills and livers was detected, however only temporary. Pb was proved to inhibit the heme-synthesis in red blood cells, but it was not possible to connect (or exclude) accumulation of Cu, Zn and Sb to any specific toxic effect. We found indications that flushing events in shooting ranges potentially may cause chronic accumulation of Pb rather than Cu, Zn and Sb. Other findings of interest were lethal respiratory dysfunction caused by precipitation of Al on gills in a uncontaminated control stream, and acute mortality caused by ferrous iron detected in a pre-survey of the shooting range. In aquatic risk assessment of pollution from rifle ranges established on peat, it is necessary to incorporate focus on these metals as well.