Biotic ligand model과 종 민감도 분포를 이용한 토양 공극수 내 Cu의생태독성학적 허용농도 결정에 미치는 환경인자의 영향

Abstract

Biotic ligand model (BLM) and species sensitivity distribution (SSD) were used to determine the site-specific Cu threshold concentration (5% hazardous concentration; HC5) in soil pore water. Model parameters for Cu-BLM were collected for six plants, one collembola, and two earthworms from published literatures. Half maximal effective concentration (EC50{Cu2+}), expressed as Cu2+ activity, was calculated based on activities of major cations and the collected Cu-BLM parameters. The EC50{Cu2+} varied from 2 nM to 251 μM according to the variation in environmental factors of soil pore water (pH, major cation/anion concentrations) and the type of species. Hazardous activity for 5% (HA5) and HC5 calculated from SSD varied from 0.076 to 0.4 μg/L and 0.4 to 83.4 μg/L, respectively. HA5 and HC5 significantly decreased with the increase in pH in the region with pH less than 7 due to the decrease in competition with H+ and Cu2+. In the region with pH more than 7, HC5 increased with the increase in pH due to the formation of complexes of Cu with inorganic ligands. In the presence of dissolved organic carbon (DOC), Cu and DOC form a complex, which decreases Cu2+ activity in soil pore water, resulting in up to 292-fold increase in HC5 from 0.48 to 140 μg/L.