"The dioxin that we have (at Castle) is not the dioxin causing the problem for the city of Atwater," said county spokeswoman Elaine Post.
Dioxins, poisonous compounds known to cause cancer and birth defects, were discovered in Atwater's wastewater last year. Since then the city and county have battled back and forth over who will clean up the hazardous materials.
The new report says the county has isolated the dioxin source at Castle and will clean it up by summer's end, said Post.
Other dioxins found in Atwater's wastewater are coming from some other source, said the report.
"It is not the Castle sewer system, but some other influence on the Atwater treatment plant (that is) creating the city's high readings," said the report.
The Atwater Federal Penitentiary and Winton also use Atwater's wastewater system. Testing found some dioxin coming from those sources, but not in very high levels, according to Public Works Director Dave Church.
The county's report says recent tests show a drastic improvement in dioxin levels pouring into Atwater's wastewater, said Church.
Castle shut down two sewer lines that showed high levels of dioxin in October 2005; that stopped the flow of dioxins into Atwater's wastewater, according to the new report.
Atwater Mayor Rudy Trevino has made it his personal mission to get the dioxin cleaned up before he leaves office in November.
At Monday night's City Council meeting he gave a history of the dioxin issue, then asked the audience for help on shining a light on the problem.
"Ladies and gentlemen, you and your children are at risk," said Trevino. "Now you're all informed as I am, and now you're all guilty as I am if you don't do something about it."
Dioxin is one of the ingredients in Agent Orange and Trevino said he believes his grandson was born with birth defects because he was exposed to the toxin.
Post said she saw no health threat from the dioxin at Castle.
"At Castle there is no public health concern," said Post. "It's contained, it's not flowing anywhere. The residents and businesses at Castle are not in danger."
As for the dioxin in Atwater's wastewater, it's not much of a health concern either, according to the Regional Water Quality Control Board.
"If this were a water body that someone was drinking or they were obtaining fish from to eat, this would be a high priority cause for concern," said Supervising Engineer Bert Van Voris. "But this is sewage, which isn't accessible. Nobody in the general public is going to be accessing it."
Church, the public works director and the only Atwater official who had seen the county's new report late Tuesday, said the report showed progress. But the city plans to do further testing.
"On face value, it looks like they've been doing their work out there," said Church of the county's cleanup efforts. "That's all we ever asked them to do -- find it and stop it."
Reporter Leslie Albrecht can be reached at 385-2484 or lalbrecht@mercedsun-star.com.
