Tracking pesticide turnover in soils with stable isotope tracers

Prior to the final approval by ECHA, each chemical has to be tested for its persistence. A chemical is persistent, when it is slowly or not transformed, and the amount of non-extractable residues (NERs) is high. High NERs is criterion for declining the approval of the chemical. The NERs cannot be extracted from the soil or sediment; they can be potentially toxic chemicals (xenobiotic NERs) or harmless microbial biomass (biogenic NERs). The NER analytics using standard OECD mass balance tests applying carbon isotopes is difficult and laborious. In contrast to carbon, a large proportion of the incorporated deuterium atoms into microbial biomass will be quickly released to water, thus biogenic NERs will not contain high amounts of heavy hydrogen isotope. Therefore, this new deuterium stable isotope probing approach will simplify NERs speciation without the need of extensive biogenic NER analytics. Thereby, it can support the chemical industry and the authorities in the evaluation of a chemical’s persistence and the associated environmental risk assessment.

For more information, please refer to: Cefic-LRI Innovative Science Award: http://cefic-lri.org/news/cefic-lri-to-invest-e100000-into-better-testing-methods-for-persistent-chemicals/

**** invited by Tillmann Lüders, Ecological Microbiology