Amsterdam Institute for Life and Environment (A-LIFE), Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.
Syngenta - Environmental Safety, Jealott's Hill, RG42 6EY Bracknell, United Kingdom of Great Britain and Northern Ireland.
Sci Total Environ. 2024 Mar 20;917:170206. doi: 10.1016/j.scitotenv.2024.170206. Epub 2024 Jan 24.
To account for potential differences in bioavailability (and toxicity) due to different soil organic matter (OM) contents in natural and artificial soil (AS), in the current European environmental risk assessment (ERA) a correction factor (CF) of 2 is applied to toxicity endpoints for so called lipophilic pesticides (i.e. log K > 2) generated from laboratory tests with soil invertebrates. However, the appropriateness of a single CF is questioned. To improve the accuracy of ERA, this study investigated the influence of soil OM content on the toxicity to the earthworm Eisenia andrei of five active substances used in pesticides covering a wide range of lipophilicity. Laboratory toxicity tests were performed in AS containing 10 %, 5 % and 2.5 % peat, and a natural LUFA 2.2 soil (4.5 % OM), assessing effects on survival, biomass change and reproduction. Pesticide toxicity differed significantly between soils. For all pesticides, toxicity values (LC, EC) strongly correlated with soil OM content in AS (r > 0.82), with toxicity decreasing with increasing OM content. Obtained regression equations were used to calculate the toxicity at OM contents of 10.0 % and 5.0 %. Model-estimated toxicity between these soils differed by factors of 1.9-3.6, and 2.1-3.2 for LC and EC values, respectively. No clear relationships between pesticide lipophilicity and toxicity-OM relationships were observed: the toxicity of non-lipophilic and lipophilic pesticides was influenced by OM content in a similar manner. The results suggest that the CF of 2 may not be appropriate as it is based on incorrect assumptions regarding the relationships between lipophilicity, OM content and toxicity. Further research should be conducted to understand the mechanistic link between toxicity and soil OM content to better define more chemically and ecologically appropriate CFs for ERA.
为了说明由于天然土壤和人工土壤中不同的土壤有机质含量（OM）而导致的生物利用度（和毒性）的潜在差异，在当前的欧洲环境风险评估（ERA）中，对于源自实验室土壤无脊椎动物测试的所谓亲脂性农药（即 log K>2）的毒性终点，应用了 2 的校正因子（CF）。然而，单一 CF 的适宜性受到质疑。为了提高 ERA 的准确性，本研究调查了土壤 OM 含量对五种广泛亲脂性农药活性物质对蚯蚓 Eisenia andrei 的毒性的影响。在人工土壤中进行了实验室毒性测试，该人工土壤含有 10%、5%和 2.5%的泥炭，以及天然 LUFA 2.2 土壤（4.5%OM），评估对生存、生物量变化和繁殖的影响。农药毒性在土壤之间有显著差异。对于所有农药，毒性值（LC、EC）与人工土壤中的 OM 含量呈强相关性（r>0.82），毒性随 OM 含量的增加而降低。获得的回归方程用于计算 OM 含量为 10.0%和 5.0%时的毒性。这些土壤之间模型估计的毒性差异为 1.9-3.6 倍，LC 和 EC 值分别为 2.1-3.2 倍。未观察到农药亲脂性与毒性-OM 关系之间存在明显关系：非亲脂性和亲脂性农药的毒性以类似的方式受到 OM 含量的影响。结果表明，2 的 CF 可能不合适，因为它基于关于亲脂性、OM 含量和毒性之间关系的不正确假设。应进一步开展研究，以了解毒性和土壤 OM 含量之间的机制联系，从而更好地为 ERA 定义更具化学和生态适宜性的 CF。
