Keywords: stream pyrethroids Insecticides Substances: Permethrin (RLLPVAHGXHCWKJ-UHFFFAOYSA-N) Deltamethrin (OWZREIFADZCYQD-NSHGMRRFSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N)