An environmental group that tracks water quality says the latest report is further evidence that stricter regulations on farmers are needed. Meanwhile, a local farm group insists that more vigilant testing in the past four years has uncovered pesticide residue that previously would have gone undetected.
The Central Valley Regional Water Quality Control Board allows farms to send runoff into waterways while cities and industry must apply for pollution discharge permits. In 2003, the state took a step toward stricter regulation by requiring agricultural watershed groups to test water and report the results in lieu of pollution discharge permits.
Bill Jennings, executive director of the California Sportfishing Protection Alliance, said even if there were only one or two high readings, that should prompt state regulators to impose stricter rules on farmers.
"If you get one hit, you're guaranteed to get other hits," Jennings said, adding that not all of the 58 Delta sites named in the report were tested consistently, and of those tested for pesticides, more than 60 percent showed elevated levels of pesticides.
"This monitoring program isn't rigorous enough to define water quality," he said, "but this is the first snapshot, and it says we have serious problems."
Bruce Blodgett, executive director of the San Joaquin Farm Bureau Federation, said farmers have improved their use of pesticides so that there is less toxic runoff.
"We've seen improvements in the testing process," he added. "We can detect more and we've seen improvements in practices on the ground."
He added that the expense the regulation environmental groups seek would put farmers out of business.
"Their (CSPA's) position has not changed, and we suspect that their position will never change," he said.
Jennings said the effort required by individual farmers need not be too expensive.
"What we did suggest is that every farmer file a notice of waste discharge," he said. "Every farmer needs to do a pollution action plan for his farm."
In the report released two weeks ago, Grant Line Canal showed 29 cases between summer 2004 and the end of 2006 of pesticide levels that were high enough to kill water fleas, a species used to detect the presence of pesticides. There were 42 detections of high pesticide levels at Pixley Slough north of Stockton and 19 on the San Joaquin River near Manthey Road. Most of the 58 test sites had less than 10 cases of high pesticide levels. In all, 58 test sites showed 209 cases of elevated levels of pesticides.
Those who work with farmers say the report is a valuable first step.
"Things are better than they were two years ago," said John Meek, chairman of the San Joaquin and Delta Water Quality Coalition, which tests the water and reports the results to the state and tries to pinpoint where pollution comes from.
"Part of the program is to get people aware of what they're doing and make sure they're doing it properly," he said. "We're meeting with the growers and said, 'Look guys, you need to be aware of what's going on here,' and a lot of them took it to heart."
Contact reporter Bob Brownne at email@example.com.