21
Mar
Dangerous Levels of DDT Still Plague San Francisco Bay
(Beyond Pesticides, March 21, 2012) A half-century after California officials discovered that large amounts of the pesticide DDT had been discharged into a San Francisco Bay canal, the chemical is still poisoning fish and posing a threat to human health despite numerous cleanup attempts. After years of limited success with clean-up, the U.S. Environmental Protection Agency (EPA) has launched a three-year plan to pinpoint the cause of continuously high DDT levels and engage the surrounding community in cleanup and education efforts.
The former plant and the adjacent canal, called the Lauritzen Channel, an inlet of the greater San Francisco bay, is one of the most polluted places in the nation. DDT levels have not decreased in the channel even after numerous dredging and other mitigation measures. In fact concentrations have increased. By 2011, DDT concentrations exceeded 1994 levels and some fish have DDT levels in their tissues hundreds of times higher than their counterparts in the rest of the San Francisco Bay. EPA said earlier this month it is launching a three-year plan to help unravel the mystery of why cleanup attempts are failing, and will work with the city to increase awareness among anglers who rely on bay fish to supplement their diets. The area is used by recreational and subsistence fishermen, despite multi-lingual signs posted by the state warning against eating fish or shellfish from the canal because of DDT pollution. The Action Plan includes collecting additional data to be used to formulate a long-term cleanup solution as well as implementing a short-term immediate cleanup action to determine the source of DDT re-contaminating the Lauritzen Channel, and to evaluate sediment movement in and out of the Channel. EPA will also continue to collect sediment, mussel, and fish samples to evaluate the trend of DDT in the environment.
DDT, an organochlorine pesticide banned by the U.S. in 1972, was dumped into a shipping channel near the city of Richmond by the pesticide processing company United Heckathorn starting in the late 1940s and ending in 1966. DDT can cause liver damage and seizures, and EPA considers it a possible carcinogen. A long line of recent studies associated with the negative health effects of DDT include breast cancer and autism. Despite the fact that DDT was banned in the U.S. 40 years ago, concentrations of this toxic chemical’s major metabolite, DDE, have remained alarmingly high in many ecosystems, including surface waters, the arctic, and even U.S. national parks. Organochlorines like DDT have also been linked to a number of adverse effects to human health, including birth defects and diabetes. Exposure to DDT can occur by eating contaminated fish, which is why subsistence fishing communities like those in Richmond are considered at risk. The California’s Office of Environmental Health Hazard Assessment (OEHHA) has issued fish advisories that recommend no consumption of fish from the Lauritzen Channel and recommends limited consumption of fish from San Francisco Bay.
California water quality officials first discovered DDT pollution in San Francisco Bay in 1960. At the time, DDT was still used to control mosquitoes for malaria abatement, and in agriculture. During this time, studies found DDT was killing bald eagles and other bird species along the California coast, and that the pesticide bioaccumulated in the tissues of animals throughout the food chain. Records show that California designated the canal as a Superfund site in 1982, and state tests of mussels at the time found the highest levels of DDT ever recorded in the state. EPA Superfund records show its first cleanup attempt was in 1990, when layers of pesticide residue up to three-feet thick were removed. EPA in 1998 dredged three tons of DDT-laced sludge from the bottom of the canal and contaminated soil from adjacent land. The agency also placed a cement cap over the soil to help prevent runoff into the canal.
EPA will conduct community involvement activities so the residents are better informed and involved in the cleanup effort. It also plans to brief the City Council periodically at its televised meetings, and established interest groups that keep a pulse on the environmental activities in the city.
If you live in the San Francisco Bay area and would like more information or would like to participate, contact Jacqueline A. Lane Community Involvement Coordinator, (SFD-6-3)(415) 972-3236, [email protected].
Source: Mercury News
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
