MONTEREY — A statewide study released last week shows that stream waters sampled from the Central Coast are among the most toxic in the state.
The report, the first of its kind, collected data from 2001 to 2009 from established monitoring programs throughout the state. The report, funded by the Surface Water Ambient Monitoring Program of the State Water Resources Control Board, compiled the information to show the location and sources of toxic pollutants.
About half of all 992 monitored sites throughout the state, 48 percent, had some water samples that killed aquatic organisms, such as crustaceans and fish.
On the Central Coast, a region stretching from north of Santa Cruz to just south of Santa Barbara, 56 percent of all sites tested positive for some level of toxicity. Among the 109 sites tested, 22 percent were considered “highly toxic,” compared with 12.5 percent in the second most toxic region, the Colorado River Basin.
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Although the report gives a general picture of conditions in California watersheds and coastal waters, it doesn’t include specifics about particular streams, bays or other bodies of water, said John Hunt, who co-authored the report.
“We wanted to put together a statewide perspective for the board,” he said.
Hunt, who works for the Department of Environmental Toxicology at UC Davis, was quick to point out that toxicity measurements are complex.
The water considered “highly toxic” can be lethal for sensitive animals, such as freshly hatched fish, but is not equally dangerous for humans.
Levels of toxicity do, however, affect the overall health of an ecosystem.
Agricultural areas throughout the state, such as the Salinas and Central valleys, had the most sites labeled “highly toxic,” at 35 percent. Urban areas, at 30 percent, followed closely. Not surprisingly, undeveloped areas were the cleanest, testing “highly toxic” at just 5 percent of the sites.
“I think most people think that all the water quality problems come from farms and industry,” Hunt said. “In a lot of cases, especially in residential and urban areas, the toxicity is coming from the public’s use of pesticides.”
Most toxic water samples contain a cocktail of chemicals. This report tries to identify the source of the toxicity. Pesticides, they found, cause the most toxicity, partly because, Hunt said, pesticides are easier to identify than industrial compounds.
Commercial and home use of pesticides — such as those used to control ants — can be the primary source of toxicity in urban and residential waters, Hunt said. In the long term this, he believes, will be a greater problem than agricultural sources of pollution.
“The farmers are cleaning up their act much quicker than the public is. I’ve got to give Central Coast growers a lot of credit for taking initiative,” Hunt said.
He believes agricultural areas will see improvements over the next five years. He is less upbeat about residential areas. “It is harder to reach the public than to work with farmers,” he said.
A more in-depth report will be published in March to analyze toxicity trends throughout the state.
Hunt said that study will be followed by comprehensive reports on each of the five regions, noting that the Central Coast will likely get high priority due to its greater levels of toxicity.
To view the current report, visit http://www.waterboards.ca.gov/water_issues/programs/swamp/docs/reports/tox_rpt.pdf
Tribune writer Sarah Linn contributed to this report.