ISOTOPEST · ISOtope TOols for assessing PESticide faTe in the environment

Assessing the source and fate of pesticides in the environment is vital for improving European water management policies and remediation actions. Although compound specific isotope analysis (CSIA) has proved to be a valuable tool to identify sources and track and quantify pollutant degradation in environmental systems, its application to pesticides is still emerging. There are currently some analytical challenges that restrict the possibilities to exploit the full potential of CSIA in pesticides for environmental applications, mainly related with low pesticide concentrations in environmental matrices. The first task of this project aims to overcome these barriers by optimizing extraction and analytical methods for measuring isotope ratios in an unexplored pesticide of high environmental concern: the organochlorine insecticide methoxychlor. Understanding the processes of transformation of pesticides and their associate isotope fractionations is crucial to give a sound base on CSIA application in real case studies. Nevertheless, the database of isotope fractionations associated to different transformation reactions for each pesticide is extremely incomplete. The second task of this project aims to increase this database by performing laboratory experiments for assessing biodegradation of methoxychlor and the herbicide atrazine. Finally, to take the next step and bring CSIA of pesticides to the field, the third task of this project is focused on application of CSIA in two contaminated sites for assessing the fate of the target pesticides (atrazine and methoxychlor) and their metabolites. This will provide a further demonstration of the options of CSIA in the evaluation of strategies for natural or induced attenuation, and to trace the sources, sinks and fate of pesticides in the environment. This project will thus contribute to the competitiveness of Europe in environmental monitoring, risk assessment and contamination mitigating concepts of pesticides.