Evaluation of the Risk of Pb and Cd Deposition on Bulgarian Forests Using a Critical Load Approach

Sonya Damyanova1*, Toma Tonchev2
1- University of Forestry, Faculty of Ecology and Landscape Architecture, 10 Kliment Ohridski Blvd., 1797 Sofia, BULGARIA
2 - University of Forestry, Faculty of Forestry, 10 Kliment Ohridski Blvd., 1797 Sofia, BULGARIA
*Corresponding author: sonya_damyanova@abv.bg
Abstract. The current study was designed to calculate the critical loads of lead (Pb) and cadmium (Cd) for forests in different mountainous sites in Bulgaria and to assess a risk of damage caused by these metals for 2017 year. Steady-state mass balance model for input and output metal fluxes from an ecosystem was applied, based on the criterion for ecotoxicological protection. These mass fluxes were calculated based on measured data. The value of critical load for Cd was considerably lower than those for Pb. That means all forest ecosystems were more sensitive to the Cd deposition compared to the Pb one. It was found that the critical load for Pb and Cd for coniferous stands was higher than those for the deciduous one. Exceedances of critical loads of Pb and Cd for four study sites during the 2017 year were calculated and used as a criterion for risk assessment against heavy metal pollution. Exceedances of critical loads for both metals were found, e.g. a real risk of the harmful effect of Pb and Cd for all study sites.
Key words: critical loads, heavy metals, risk assessment, forest ecosystems, lead and cadmium.

Ecologia Balkanica, 2019, Special Edition 2, pp. 147-153
Article № eb.19SE204 [Full text - PDF]pdf

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