Lower Deschutes River Now Listed Under Clean Water Act for Pesticide

The Oregon Department of Environmental Quality (ODEQ) released its draft Integrated Water Quality Report in September, 2019.  The Federal Clean Water Act (CWA) requires Oregon to submit the report to the Environmental Protection Agency (EPA) every two years.

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Photo by Brian O’Keefe

This year’s draft report contains an unpleasant surprise.  Chlorpyrifos is, for the first time, listed as limiting water quality in the lower Deschutes River for the lowest 96 miles of the river.  That means that once the final report is submitted, the lower Deschutes River will be listed under CWA §303(d) for its ongoing limitations of water quality due to warm temperature, high pH and low dissolved oxygen and will now include chlorpyrifos.

Chlorpyrifos is a widely used agricultural pesticide that is toxic to insects, fish, birds and humans.  It is a neurotoxin (cholinesterase inhibitor) that is chemically related to the World War I nerve gas, sarin.

Chlorpyrifos was detected by ODEQ in the stretch of the Deschutes River water located between Pelton Dam and the Pelton Reregulation Dam (the two lowest dams of the Pelton-Round Butte Hydroelectric Complex) in 2018.

The detected levels were in excess of all EPA guidance for aquatic levels of chlorpyrifos as chlorpyrifos is very toxic to aquatic insects and fish of many species.

Chlorpyrifos is applied via spray application to agricultural fields and is widely used for many kinds of crops.

Chlorpyrifos has a controversial history.  Its use has been banned in Europe and was up for consideration for a ban here in the U.S., but the ban proposal was dropped by the EPA in 2017 at the direction of the presidential administration.  A statewide ban has been proposed here in Oregon, but failed in the Oregon legislature in the 2019 legislative session.

DRA has been in consultation with a legislative representative and some other organizations.  We are too late to seek another at a ban in 2020 due to the short legislative session, but will prepare for the 2021 session.