News Release (C-63-95)

For Immediate Release (C-63-95)
Contact: Communications Office (916) 324-9670
December 13, 1995

555 Capitol Mall, Suite 525
Sacramento, CA 95814

Cal/EPA Prohibits Bay Area Sales and Use of Two Pesticides to Reduce Impact on Bay Estuaries

SACRAMENTO -- Cal/EPA today announced the ban on the sale and use within nine Bay Area counties of two pesticides which have been proven harmful to San Francisco Bay and its estuaries. The pesticides are used in sewers and in large air conditioning systems.

Emergency regulations went into effect this week which prohibit the sale and use of pesticide products containing copper sulfate or tributyltin (also called TBT) in Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma counties.

"This ban is the result of excellent cooperation among DPR, the San Francisco Regional Water Quality Control Board, and several Bay Area publicly-owned water treatment plants," California Secretary for Environmental Protection James M. Strock said. "We were presented with a difficult environmental challenge and Cal/EPA worked as a team  with local agencies to protect the environment." 

"We took a common-sense approach," Strock added.  "Because we know that these products have important uses, our scientists developed information on alternative methods for controlling root intrusion in sewer lines and microorganisms in many air conditioning systems.  This is an excellent example of how environmental and economic  progress can be successfully combined."

The prohibition affects copper sulfate-containing pesticide products that are poured into sewers and drains to kill plant and tree roots. The affected TBT products are used in cooling towers in larger air conditioning systems to control microorganisms (such as bacteria, algae, and fungi) that can cause fouling.

Over the past several years, copper and TBT levels have exceeded acceptable levels in the Bay and its estuaries, prompting the Regional Water Board to mandate that water treatment plants reduce the two chemicals in their discharges to acceptable levels by 1996 or face penalties up to $25,000 a day and possible suspension of their operating permits.

In February 1994, Assemblyman Byron Sher (D, Palo Alto) introduced AB 3394, which would have allowed the state s regional water quality control boards to prohibit the sale, use, and discharge of pesticides containing copper and TBT into water systems.

However, after discussions among Assemblyman Sher, DPR, Cal/EPA, and representatives of Bay Area water treatment plants, it was decided that DPR should develop a solution using existing regulatory authority.

Although the copper and TBT products are used in relatively small amounts, the way they are applied--poured either directly or indirectly into sewers--has a disproportionate impact on water treatment plants and the treated water they discharge into the Bay and estuaries.  Water treatment typically does not remove all pesticide residues.   The Bay is particularly vulnerable to contamination because it has many shallow estuaries with little natural flushing or surface water recharge.

Because low-level contamination can hurt marine life such as crabs, clams, and microscopic aquatic organisms at the bottom of the food chain, the Regional Board in 1992 set a limit for TBT of 0.005 parts per billion and 4.9 ppb for copper in water discharged from treatment plants.  

Many sources of copper are not easy to control. They include abandoned mines, drinking water pipes, brake linings, human wastes, food wastes, and laundry gray water. A 1994 study by the Palo Alto Regional Water Quality Control Plant of trace metals in wastewater determined that of all metals evaluated, copper should be given a high priority for control, with the focus being on reducing use of copper-containing root control compounds.

Potential sources of TBT are entirely pesticidal, including some cooling water system additives, antifouling paints used on boats, protective wood treatments, commercial toilet bowl cleaners, and disinfectant carpet cleaners.  A second Palo Alto study determined that the TBT contamination was primarily the result of discharges from cooling water systems.  Studies of copper and TBT contamination by other water treatment agencies have drawn similar conclusions.

"This pollution control strategy focuses the use of these powerful chemicals in the places where no acceptable alternatives are available.  The cooperation and coordination demonstrated here are the type of efficiency Governor Wilson envisioned when he created Cal/EPA," Strock concluded.

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