Community-level effects of a neonicotinoid pesticide on the metabolism of freshwater microorganisms

This study provides an ecotoxicological assessment of the effects of the neonicotinoid dinotefuran on freshwater microorganisms. Epilithic biofilm was sampled from a small stream and exposed to dinotefuran for 14 days in Biolog EcoPlates. In general, we found that a concentration of 0.100 mg l^-1 of dinotefuran induced the microorganism community to catabolise carbon sources faster. However, catabolic activity varied depending on the type of carbon source. Catabolism increased for Putrescine (+4673 %), Serine (+376 %), Galacturonic Acid (+206 %), Pyruvic Acid Methyl Ester (+177 %), and Gamma Amino Butyric Acid (+113 %); and decreased for Arginine (-59 %), Asparagine (-26 %), and Mannitol (-21 %). This is the first study in which EcoPlates have been used to investigate the effects of dinotefuran on freshwater epilithic biofilm at an environmentally realistic concentration.