Our joint research fellow with Estonian Environmental Research Centre Dr. Riin Rebane and joint PhD candidate Siiri Saaver participated in the study “Analysis of pesticide traces and dynamics in surface and groundwater” . In this study, 137 surface and groundwater samples from all over Estonia were analysed with a targeted screening of 135 pesticides. From 137 analysed samples 49 pesticide traces were detected in more than half of the samples. In 34 samples 9 pesticides and their metabolites exceeded the allowed concentration level of 0.1 μg/L. In 9 samples pesticides and their transformation products exceeded 0.5 μg/L. Interestingly, the main compound found (in 26 samples) was chloridazon-desphenyl, which is a metabolite of pesticide chloridazon that is not registered on Estonian market and therefore not sold, which makes the determination of the origin of this compound complicated. It needs further research whether it is a remnant of Soviet times and slowly moving in the soil towards groundwater or if it is in use now.
This study was also reported in news portal Novaator and in environmental TV show Osoon
Moreover, there are hundreds of different pesticides and targeted screening methods usually look for compounds that are banned or known to be problematic. This study used the broader list of pesticides than regular yearly monitoring of pesticides indicating that broader coverage of potential pollutants is needed. Therefore, there is a need for the suspect and non-target screening methods for detecting more compounds and their metabolites.
In collaboration with Estonian Environmental Research Centre, our group has also contributed to studying and developing the non-target approach. Namely, Gunnar Printsmann developed in his master thesis suspect and non-target screening method for groundwater using high-resolution mass spectrometry which also included pollutants database. He found and confirmed a new industrial pollutant dibutyl phthalate in one sample from North-Eastern Estonia.