Overvåking av utvalgte miljøgifter i Mjøsa 2016

Abstract

Metaller, PAH og omdanningsprodukter av PAH ble undersøkt i lake, hork og andemusling fanget ved Helgøya og utenfor renseanlegg ved Mjøsa. Konsentrasjonen av bly, nikkel, kadmium, sink, krom, kobber og arsen i horke- og lakelever var lav. Kvikksølvkonsentrasjonen i lakemuskel var høy (0,3-0,9 mg/kg) og omtrent som i fiskespisende ørret i Mjøsa. Kvikksølvkonsentrasjonene i horkemuskel (0,15-0,35 mg/kg) var omtrent på nivå med planktonspisende krøkle i Mjøsa. Konsentrasjonene av PAH-forbindelser i andemusling og PAH-metabolitter i fisk var lave.

Metals (lead, nickel, cadmium, zinc, chromium, copper, arsenic, and mercury) and metabolites of PAH (polycyclic aromatic hydrocarbons) were determined in burbot (Lota lota) and ruffe (Gymnocephalus cernuus L.) caught in Lake Mjøsa outside Helgøya and waste water treatment plants at HIAS, Lillehammer, and Gjøvik. Furthermore, 16 PAH substances were determined in duck mussel (Anodonta anatina) caught at Helgøya and HIAS. The concentration of lead, nickel, cadmium, zinc, chromium, copper, and arsenic in the liver of ruffe and burbot was low and at a level that can be expected in lakes without known local point sources. Lead, nickel, cadmium, and zinc were higher in ruffe liver than in burbot liver, whilde the opposite was true for arsenic. The mercury level was 4 times higher than the environmental quality standards. The mercury level in burbot muscle was approximately at the same level as that found in fish eating trout in Lake Mjøsa (0.3-0.9 mg/kg ww). Mercury concentrations in ruffe muscle were highest at Lillehammer and Helgøya and lowest at HIAS, and was approximately at the same level as that found in smelt feeding mainly on plankton in Lake Mjøsa (0.15-0.35 mg/kg ww). Arsenic varied between the station and decreased in the sequence Helgøya > HIAS > Gjøvik > Lillehammer. The concentration of PAH substances in mussel and well below the environmental quality standard. The concentration of PAH metabolites in ruffe and burbot bile was also low, and well below levels that are expected to be harmful. The concentration of the PAH metabolite 1-OH-pyrene was higher in burbot than in ruffe and decreased in the sequence Gjøvik > HIAS > Helgøya > Lillehammer.