Keywords: stream pyrethroids Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Acrinathrin (YLFSVIMMRPNPFK-WEQBUNFVSA-N) Cyphenothrin (FJDPATXIBIBRIM-UHFFFAOYSA-N) Deltamethrin (OWZREIFADZCYQD-NSHGMRRFSA-N) Cypermethrin (KAATUXNTWXVJKI-UHFFFAOYSA-N)