Undersøkelse av bly og kobber i abbor (Perca fluviatilis) hentet fra Steinsjøen skytefelt

Small arm shooting ranges are major deposits of lead (Pb), copper (Cu), antimony (Sb), and zink (Zn) from use of ammunition. Metals and metalloids from the ammunition residues may leach into the soil and surrounding watercourses and may pose a threat to exposed wildlife and humans. Discharge of elements is dependent on several factors such as soil properties, hydrological conditions, precipitation and time. There is reason to believe that discharge of heavy metals into the watershed may influence organisms living there. In this study perches (Perca fluviatilis) from three ponds in Steinsjøen military small arm shooting range were caught in order to reveal if the fishes were exposed to increased levels of Pb and Cu and if the exposures have had an effect on their condition. In addition ALA-D activity, which is a biomarker for Pb-exposure in blood, was analyzed in the fishes. Two lakes are recipients for heavy metals, Storvatnet, Brenntjern and one lake was used as control. Water samples and bottom sediments from the lakes were taken to reveal heavy metals concentrations and deposition. Water from both Storvatnet and Brenntjern had increased levels of Pb (3.2 and 2.6 µg/L respectively) and Cu (17.9 and 12.2 µg/L respectively), whereas the water from Torvfasttjern was not influenced by heavy metals. Sediments from Storvatnet and Brenntjern had increased levels of Pb (182 and 139 mg/kg/ dry weight respectively) and Cu (101 and 91 mg/kg/ dry weight respectively), whereas sediments from Torvfasttjern had relatively low concentrations (69 and 12 mg/kg/dry weight Pb og Cu respectively). These results indicate that the two ponds, Storvatnet and Brenntjern, are recipients of heavy metal discharge from munitions. The concentration of Pb and Cu in the perch from either of the lakes did, however, not exceed the levels considered as normal for freshwater fish and there were no significant differences in concentration levels in the fishes between the lakes. Filet had mean Pb concentrations of less than 0.2 mg/kg wet weight and a mean Cu-concentration of less than 1 mg/kg wet weight. The Norwegian Food Safety Authority recommends an upper limit of Pb concentration in fish filet of 0.3 mg/kg wet weight. Therefore, it is no reasons to believe that intake of fish from these lakes represent any risk. There was, however, indications on Pb and Cu accumulation in the fish liver from Storvatnet and Brenntjern since the concentration increased with fish size. Such correlation could not be seen in fish from Torvfasttjern. The Pb and Cu concentration in the fish liver (~10mg/kg wet weight) were, however, within what are considered as normal (1-40 mg/kg wet weight), and the fish appeared to be in good condition. ALA-D activity was, however, reduced in the fish from Brenntjern and Storvatnet, indicating exposure to increased levels of Pb. The significance of this effect is not known. The ponds at Steinsjøen shooting ranges are influenced by peat, which probably will reduce the bioavailability and toxicity of the metals. A larger portion of the metals will be bound up into particles. We recommend performing studies on fish exposed to sudden changes in water metal concentrations, do fishing and testing of fish from heavy metals influenced lakes with a different chemistry and study effects of mixtures based on the knowledge that water living organisms are exposed to a combination of Pb, Cu and Sb.