Keywords: trace analytics toxicity stream pyrethroids Insecticides Systems: stream Substances: Bifenthrin (OXCDWLBJSLVWHB-LKRLXIKPSA-N) Chlorpyrifos (SBPBAQFWLVIOKP-UHFFFAOYSA-N) Allethrin (ZCVAOQKBXKSDMS-UHFFFAOYSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N)