Abstract
Mercury is a highly toxic compound and a significant environmental pollutant. MeHg is of particular interest because of its high bioavailability. This study analyses the mercury concentration of cormorants (Phalacrocorax carbo sinensis) in Innlandet, Norway, to assess the bioavailability of mercury and to identify any regional differences related to varying intensities of forestry practices (clear-cutting). A total of 51 cormorants were analyzed for hepatic mercury levels, and 29 of these were further examined for mercury concentration in their muscle samples. cormorants were collected from hunters, and necropsies were carried out, after which the samples were sent to ALS Scandinavia AB laboratory for analysis. The Kruskal-Wallis test was first used to observe any differences in mercury concentration between the valleys and the forestry practices. Afterwards, a general linear model (GLM) was used to test which factors are significantly related to the mercury content in cormorants. The average mercury content in the cormorants was high (12.36 ± 14.62 mg/kg DW) with a significant amount passing values known to cause adverse effects, and some even with reaching lethal levels (41.46 and 74.8 mg/kg DW). Results also showed low Se:Hg molar ratios and negative Health Benefit Value for Selenium (HBVSe), in both liver and muscle. Therefore, the mercury in the cormorants was determined to be bioavailable, rendering the cormorants unfit for consumption. The GLM model indicated higher mercury was found in cormorants with more volume logged and tree cover loss in their habitats. In general, the results showed that mercury was not only bioavailable in the cormorants, but also that its value was impacted by the forestry intensity (clear-cutting).
