Keywords: stream pyrethroids Insecticides Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Acrinathrin (YLFSVIMMRPNPFK-WEQBUNFVSA-N) Cyfluthrin (OFHFONYRMVKULH-WNYJFNBPSA-N)