RIPON — A year of sampling near Ripon and two other locations found no unhealthy residues from 33 pesticides, a state agency reported.
The findings were questioned by the Pesticide Action Network, which long has been critical of government oversight of the chemicals.
The California Department of Pesticide Regulation last week released its 2012 results from sampling sites near Ripon, Salinas and Shafter, in Kern County. It was the second year for the monitoring, which took place weekly near towns surrounded by intensive agriculture.
The agency said no residues were detected in 94.5 percent of the samples, and the levels in the rest were well below thresholds for protecting people from pesticide-related illnesses.
"This is reassuring news for residents," said Brian Leahy, the department director, in a news release. "Our monitoring in 2012 shows that none of the pesticides exceeded their screening levels, indicating a low health risk to the people in these communities."
Leahy credited state and county rules on pesticide use with keeping the levels down.
The pesticides detected the most often were chlorpyrifos and MITC, found at all three locations 28 percent of the time.
The Pesticide Action Network, based in Oakland, said monitoring with its "drift catcher" device found levels that put children at risk.
"DPR sampled in a systematic but not targeted manner, with samples being taken once per week for 12 months," staff scientist Emily Marquez said in an e-mail. "The most important time to monitor is during the times of peak use."
Most farmers rely on pesticides to deal with insects, fungi, weeds and other problems that can cut into their yields. They say the chemicals are sprayed under strict rules aimed at protecting farmworkers, nearby residents and waterways, and are used only when truly needed rather than on a strict schedule.
The Pesticide Action Network urges an "agroecological" approach, with measures such as crop rotation and natural predators to disrupt pests.
Bee staff writer John Holland can be reached at firstname.lastname@example.org or (209) 578-2385.