Knowledge about the occurrence of currently used pesticides and pharmaceuticals in the Amazon Basin is very limited. Therefore, we collected sediment samples from Amazonian Rivers near Manaus (Brazil) and measured concentrations of selected pyrethroid pesticides and anthelmintic drugs. Concentrations of Σpyrethroids and Σanthelmintics ranged between 19–180 and 0.05) reduced the relevance of local anthropogenic inputs and further highlighted the dominance of environmental drivers. Both exposure-based (using predicted no-effect concentration (PNEC) values for sediment) and effect-based (using sediment LC50 to Hyalella azteca and Chironomus dilutus) risk assessments consistently highlighted the high ecotoxicological risks presented by cyfluthrin, deltamethrin, and esfenvalerate, which also indirectly indicated potential risks to aquatic organisms (e.g., fish), despite their limited biomagnification potential.
Ma et al. (Tue,) studied this question.