Keywords: stream pyrethroids Substances: Chlorpyrifos (SBPBAQFWLVIOKP-UHFFFAOYSA-N) Acrinathrin (YLFSVIMMRPNPFK-WEQBUNFVSA-N) Deltamethrin (OWZREIFADZCYQD-NSHGMRRFSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N)