Bioremediation of pesticides: unravelling the anaerobic microbiological potential of oligotrophic drinking water aquifers

Abstract

Pesticides application, on agricultural fields, allows them to travel in the environment and reach surface water and groundwater. The fate and transformation of pesticides in the environment depend on environmental conditions as well as physical, chemical and biological degradation processes.Monitoring the biodegradation of pesticides in the environment is challenging, considering that traditional indicators, such as changes in pesticide concentration or identification of pesticide metabolites, are not suitable for many pesticides present in anaerobic environments. Furthermore, those indicators cannot distinguish between the different pesticide-degradation processes. For that reason, the use of molecular tools is important to monitor the biodegradation of pesticides in the environment. The development of targeted molecular tools, although laborious, allowed biodegradation monitoring by targeting the presence and expression of known catabolic geneencoding enzymes involved in the degradation of popular pesticides (i.e., atrazine, BAM). Explorative molecular tools (e.g., metagenomic and metatranscriptomic), while requiring extensive data analysis, proved to have potential for screening the biodegradation potential and activity of more than one compound at the time. The application of molecular tools developed in the laboratory and applied in controlled environments faces challenges in the field due to the heterogeneity in the distribution of pesticides as well as natural environmental differences. However, for monitoring the biodegradation of pesticides in the field, the use of molecular tools, combined with metadata and even in silico modeling, is the only way to understand what is the fate and transformation of the different pesticides present in the environment.