State Water Board says Santa Maria River is 'highly toxic'

Nov 24, 2014

Oso Flaco Lake and other estuaries fed by the Santa Maria River are sensitive habitat areas affected by toxic levels of pesticide runoff from surrounding agriculture in the Santa Maria Valley.
Credit Flickr member Rennett Stowe

A new survey by the State Water Board shows the Santa Maria River is highly toxic—and has been for years with some of the highest readings in the state for certain chemicals.

Bryn Phillips is an environmental toxicology specialist with UC Davis who has been working on this ongoing project. He says an increase in pyrethroid pesticide levels is cause for concern.

Recently the river was designated with a Total Maximum Daily Load (TMDL) restriction.

"I know that the growers down there are actively working to reduce the pesticide load going into the river," said Phillips. "And, I know that the water board down there has been working really hard with growers and other groups trying to have that happen."

Arroyo Grande Creek is also showing signs of increasing toxicity according to the report. It was listed as moderately toxic two years ago.

Other stream systems on the Central Coast are showing improving signs with reduced pollutant levels. Atascadero and San Antonio Creeks, as well as the Salinas River were moderately polluted back in 2008, but in recent years were shown to be non-toxic.