Mercury biomagnification through acidic lake food webs in relation to lake characteristics and elemental composition of aquatic organisms

Kejimkujik National Park and National Historic Site (KNPNHS) has been identified as a biological mercury (Hg) hotspot due to high levels of this contaminant in common loons and to increasing Hg concentrations In yellow perch from the park since the mid-1990s. In this study, Hg biomagnification rates (slopes of log-Hg versus nitrogen isotopes, delta15N, of fishes and invertebrates) were compared across eleven lakes in KNPNHS and found to be negatively related to total organic carbon and nutrients, but not to pH or physical attributes of lakes. The y-intercepts of these relationships were positively related to lake chemistry and Hg concentrations in primary consumer invertebrates, suggesting that their levels approximate Hg levels at the base of aquatic food webs. The total nitrogen and sulfur content (crude measures of protein and sulfur amino acids, SAA, respectively) of organisms was found to predict their Hg concentrations, which may reflect the binding of Hg to SAAs in biota.