The influence of soil organic matter content on the toxicity of pesticides to the enchytraeid Enchytraeus crypticus
Year: 2025
Type: article
Abstract: This study investigated the influence of soil organic matter (OM) content on the toxicity of five pesticides to Enchytraeus crypticus to assess the suitability of the correction factor (CF) of 2 currently applied to lipophilic (log K ow > 2) pesticides to correct for differences in bioavailability and toxicity between natural and artificial soil (AS) due to differences in OM content. Toxicity tests were performed following standardized guidelines using AS containing 10%, 5%, and 2.5% peat, and Landwirtschaftliche Untersuchungs-und Forschungsanstalt (LUFA) 2.2 soil (4.5% OM). Likelihood-ratio tests showed that soil type significantly influenced the toxicity of non-lipophilic and lipophilic pesticides, and linear regression analyses revealed that toxicity strongly correlated with soil OM content in AS (R 2 ≥ 0.96). Pesticide toxicity in LUFA 2.2 soil could not always be accurately predicted based on the OM content. Utilizing the obtained toxicity-OM regression equations, pesticide toxicity in soils containing 10.0% and 5.0% OM were modelled to assess the CF of 2. The differences in model-estimated toxicity between these soils ranged from 1.56 to 1.96 for EC 50 values, and between 1.33 and 3.40 for EC 10 values. EC 50 values were compared with data from a sister paper on Eisenia andrei to identify differences between species. Toxicity ratios were always higher for earthworms (2.08–3.21) than for enchytraeids. This study shows that the CF of 2 suffers from erroneous assumptions concerning lipophilicity, OM content and toxicity. Moreover, it highlights the importance of assessing CFs for new test species before introducing them into European soil environmental risk assessment. • Pesticide toxicity to E. crypticus decreased with increasing OM content. • Toxicity ratios based on model predictions ranged between 1.33 and 3.40. • Similar effects for non-lipophilic (log K ow ≤2) and lipophilic (log K ow >2) pesticides. • Influence of OM content on toxicity differed between E. crypticus and E. andrei. • The applied correction factor of 2 is not sufficiently scientifically underpinned.
Source: Environmental Pollution
Institution: Vrije Universiteit Amsterdam
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
SDGs: Life on land, Zero hunger
Open Access status: hybrid
Estimated APC paid: $4,090
OpenAlex ID: W4407268273