The German Environment Agency (UBA) has called for significant updates to the risk assessment of soil microorganisms exposed to agricultural chemicals, including pesticides, biocides and veterinary pharmaceuticals. The recommendations follow the MICROSOIL project, which found that current testing methods fail to capture the full scope of risks, potentially overlooking impacts such as antibiotic resistance in soil bacteria.
Expanding the Risk Framework
The existing risk assessment for plant protection products (PPPs) relies heavily on the OECD 216 nitrogen turnover test. While useful, this laboratory method does not address all potential threats to the soil microbial community. The MICROSOIL project identified five alternative testing approaches through literature review and scoring, with subsequent laboratory trials across three soils and six test substances.
Key Recommendations
UBA experts propose adding:
- Bacterial function testing using ISO 20130 (enzymatic activity).
- Structural impact assessment for mycorrhizal fungi via ISO 10832.
- Community fingerprinting methods to evaluate broader changes in microbial structure, although these require further refinement.
The study also found that repeated chemical applications, and the presence of multiple substances, can either enhance or reduce microbial degradation capacity, underscoring the complexity of soil-chemical interactions.
Implications for Industry and Regulation
These findings have far-reaching implications for professionals across the manufacturing value chain, including agrochemical producers, regulatory bodies, and food supply chain stakeholders. The omission of antibiotic resistance assessment in current veterinary pharmaceutical testing is a particular concern, given its potential to affect both environmental health and human safety.
The proposed testing enhancements would improve the detection of sub-lethal and structural impacts, enabling more informed regulatory decisions and supporting sustainable soil management practices.
