256 - Mercury Concentrations in Terrestrial Wildlife in Switzerland: A Long-term Biomonitoring Approach

"The fate of mercury as a global pollutant in all the terrestrial compartments is understudied, although the majority of atmospheric mercury is estimated to be deposited in terrestrial environments. As a result, data on the transfer and bioaccumulation of total mercury (THg) and methylmercury (MeHg), and the associated risks in terrestrial environment is scarce. Furthermore, the impact of the Minamata convention needs regular assessment, which implies the monitoring and quantification of mercury concentrations in terrestrial environments. This study focuses on bioaccumulation of THg and MeHg in terrestrial wildlife in Switzerland and aims towards developing a long-term biomonitoring plan.

Firstly, an extensive literature review of European studies was conducted to determine the concentration of THg and MeHg in a range of animals and to assist for the selection of species and tissue samples for this study. Muscle, liver and kidney tissues from 85 European roe deer (Capreolus capreolus), sampled between 2019 and 2020 in different parts of Switzerland, were analysed. The THg mean ± standard error (x̄ ± s.e) for muscle (n=81), liver (n=79) and kidney (n=82) were 3.38 ± 0.55 µg/kg, 13.11 ± 1.68 µg/kg and 90.38 ± 15.45 µg/kg of fresh weight (f.w) samples respectively. The x̄ ± s.e for MeHg in muscle, liver and kidney were 2.04 ± 0.14 µg/kg, 1.92 ± 0.22 µg/kg and 2.18 ± 0.45 µg/kg of f.w samples respectively. The highest percentage of MeHg of THg was found in muscle (x̄ ± s.e = 52.79 ± 4.1%, n=24) followed by liver and kidney. Secondly, the relationship between THg and MeHg with age and sex are investigated. Third, this study’s concentrations are compared to a previous study in roe deer tissues collected between 1984 and 1998 in Switzerland. Finally, the concentrations measured in the tissues are compared to the atmospheric mercury deposition in Switzerland."

authors: Sabnam Mahat, Marie-Pierre Ryser, Adrien Mestrot