Dioxin, High Levels of Lead Found at Chollas Lake Site

Small amounts of the potent carcinogen dioxin as well as hazardous levels of lead have been found in a 40-acre canyon area near Chollas Lake that is to be developed into a city park, according to a study released Friday.

Whether the dioxin is a health threat is unclear, but the levels of lead discovered in some samples of incinerator ash at the site were well beyond the toxic limit set by state law, and the ash should therefore be classified as a hazardous waste, the study says.

City and county officials said Friday that they have asked Earth Technology Corp., the consulting firm that conducted the study for the city, to clarify its seemingly contradictory conclusions about the amount and seriousness of the dioxin discovery.

“They were very erratic in drawing conclusions, and the conclusions tend to be inconsistent,” said William Sterling, deputy director of the Refuse Disposal Division of the city’s Waste Management Department.

City and county health officials plan to meet with the Long Beach-based consultants Monday to discuss the findings, he said, adding that the dioxin problem does not appear to be serious.

“The lead problem has pretty much been established,” Sterling said. “It needs to be dealt with and dealt with quickly.”

The city will tighten security around the canyon and set up a patrol to keep children and joggers out of the popular recreation area, he said.

Exposure to lead has been associated with lowered IQs and mental retardation in children and neurological disorders in adults.

In the short term, the report says, access to the site should be limited and a temporary cover should be placed over the ash to prevent it from becoming airborne.

No Long-Term Suggestion

The report does not recommend a long-term solution, but outlines alternatives that include capping of the ash, mixing the ash with substances that would render it inert or removal of the ash to a toxic waste dump.

Sterling said Friday that no decision has been reached on the matter but that the solution will probably be a combination of the alternatives.

Covering the ash with a 2- to 4-foot layer of earth would cost $200,000 to $400,000, he said. Using a “fixative” such as cement and lime to stabilize the ash would cost about $2 million, and total excavation would cost as much as $20 million.

Diane Takvorian, head of the Environmental Health Coalition, said the results show that the site has been “severely contaminated” and that people in the neighborhood should be warned about the danger.

“People in the surrounding area should be notified, and there should be a mailer that goes out to everyone notifying them to keep their children out of there,” she said.

The city attempted to close off the area in March after disclosures about a Navy study showing toxic levels of lead in an adjoining section of the canyon that was to be used for Navy housing.

Security Has Been Difficult

Sterling said Friday that it has been difficult to keep people out of the area.

“We’ve had some real problems,” he said. “People go out there with wire cutters and cut holes in the fence. . . . Our intention is to keep the site closed and to intensify the effort.”

The city will proceed with plans to develop the 12 acres closest to Chollas Lake into parkland, but plans to turn the rest of the area into a park have been put on hold, Sterling said.

The canyon area, just west of Chollas Lake, covers about 80 acres, the western half of which was to go to the Navy as part of a city-Navy land swap announced in 1986. The Navy planned to build housing for 300 families on its portion, but began to balk last fall after a consulting firm advised against the project unless something could be done about the high levels of lead discovered on the western half.

That discovery prompted the city to order tests on the eastern half, which has long been slated for development into a park.

In a second study commissioned by the Navy, an engineering firm estimated it would cost the city $13.5 million to remove toxic ash from the Navy housing site and instead recommended that the ash be covered over.

A Navy spokesman said Friday that the Navy is still interested in the Chollas land but that results of the latest study have not been analyzed. The consulting firm that analyzed the proposed Navy housing area did not check for dioxin, and it is not known whether the substance exists there.

The lead and dioxin in the Chollas canyon area are contained in hundreds of tons of incinerator ash left at the site during the 1940s and 1950s, when the canyon was used as a burn dump for city trash. Little is known about what was burned there, but four separate areas of ash, one of which is at least 5 feet deep, have been discovered.

During the 1970s, the city developed plans to use the canyon as a landfill, but community opposition thwarted the project.

The results of the latest test will do little to comfort some area residents who are concerned about the effects of a bulldozing operation conducted in the canyon during the summer of 1979. The city dispatched crews to construct a berm to shield the neighborhood from the noise of the anticipated landfill.

Bulldozers churned up tons of ash from the canyon and moved it to an area near Carver Elementary School. The operation spread ash dust throughout the neighborhood.

Sterling said long-term exposure to the toxic substances is greater cause for concern than is an isolated incident.

Although the Navy studies showed levels of lead more than four times the toxic limit of 1,000 milligrams per kilogram, the new study found levels more than nine times the limit.

At the request of the county Department of Health Services, the city also directed Earth Technology to test for dioxin, according to Dan Avera, chief of the department’s hazardous-materials section. Avera said the county was advised by state officials that dioxin is commonly found in the ash from garbage incinerators.

Although the concentration of dioxin appears to be less than one part per billion, further testing may be needed, the Earth Technology report says.

“While low, the concentrations are not necessarily insignificant,” the report says, adding that there is “some controversy” over acceptable levels.

But the report adds that further tests are needed to perform a risk assessment.

The report says the potential for particulates of ash--possibly containing lead and dioxin--to become airborne is “moderate to high.”

“Specifically, the low annual precipitation rate and average humidity, moderate wind speeds and the sparsely vegetated or completely exposed ash deposits along the steeply sloping berms all suggest a strong potential for chemical compounds in soil and ash to become airborne,” it says.

“The surrounding land to the north and west is residential, with high population densities in all directions within a mile radius of the site,” the report says, adding that the potential for “off-site human exposure” is high.