Bay Toxin Level Was ‘Alarming’ Before Ban on Anti-Algae Paint

A highly toxic chemical, used to keep barnacles off boats, was found in “alarmingly high” levels in mussels along the coast of San Diego, Orange and Los Angeles counties before it was banned for use on most boats last year, according to a state draft report.

Testing of the tributyltin (TBT) compound--a chemical used in paints to keep algae as well as barnacles off boat bottoms--began in 1986 as part of a larger annual study by the state’s Mussel Watch, a program that uses mussels to test water quality in bays and harbors along the coast.

A second round of samples taken by the Mussel Watch in late 1986 and early 1987, the latest date for which data is available, showed “dramatic” increases of the compound in mussel tissue, according to a copy of the report obtained by The Times and due for release next week.

Alarming Increases

“In 1986-87, alarmingly high traces of TBT in transplanted mussels were found at Richmond Inner Harbor, Monterey Bay, Port Hueneme, Marina del Rey, Los Angeles, Newport Bay and San Diego sites,” the report says.

Increases in the level of TBT in mussel tissue included 219% at the Richmond Inner Harbor in Contra Costa County, 112% at the Consolidated Slip in Los Angeles, 121% at the Newport Bay Upper Rhine Channel and 96% at the North Harbor Drive commercial basin in the San Diego Bay.

In San Diego, TBT was found at 9,820 parts per billion (ppb) in the tissue of mussels left in the Commercial Basin, near North Harbor Drive, during the first tests in January, 1986. That rose to 19,210 ppb from mussels taken from the water in December, 1986, according to the test.

“Department of Fish and Game staff continue to gather evidence strongly linking the presence of TBT in water with deterioration of bottom communities and documented harm to indicator species in San Diego Bay,” the report says.

In Orange County, the compound was originally tested at 11,100 ppb in mussel tissue taken from the Newport Bay’s Upper Rhine Channel in January, 1986. Twelve months later, mussels had TBT in concentrations of 24,520 ppb.

Effects of Ban Unknown

One TBT expert termed the Mussel Watch figures “interesting,” but said the lag time in the samples fails to show the effects of a 1988 state ban of the compound for sport and pleasure boats, the major users of TBT-laced paints.

“I would say we have regulations on the books in California that should ameliorate the problem, and it’s going to take a number of years--at least five or 10 years--to see if it works,” said Edward D. Goldberg of the Scripps Institution of Oceanography in La Jolla.

The state banned TBT paints on boats with hulls measuring 81 feet or less. Exempted are larger boats and those with aluminum hulls.

The ban was enacted because of increasing scientific evidence that TBT was one of the most toxic substances ever introduced into coastal waters. The compound kills barnacles and other organisms that attach themselves to boat hulls.

Jerry Pollock, a toxicologist for the state’s Department of Health Services, said most experts believe the ban will eventually lead to lower concentrations of TBT, which tends to settle in the sea floor and break down over time into less threatening compounds.

But he said the Mussel Watch data was important to help monitor effects of the paint additive to humans consuming contaminated fish.

“We do have concerns and we want to look at this because it is not absolutely known that those levels will drop off to nothing,” Pollock said.

Preliminary tests by the Navy have shown that TBT concentrations are easing in San Diego Bay since the state ban, said Tom LaPuzza, spokesman for the Naval Ocean Systems Center, a military laboratory in Point Loma.

LaPuzza said the Navy now has two vessels bearing TBT-treated paint that are based in San Diego. The vessels are part of a 10-ship experiment to determine how marine life is affected by the compound, which the Navy wants to use on its entire fleet to save millions of dollars in fuel and maintenance.

The Mussel Watch draft report refers to the ban, noting that larger vessels are exempt. “Therefore, the TBT problem in . . . San Diego Bay, and other coastal docking areas for large craft in California, may not lessen in the near future,” it says.

Federal regulations call for concentrations of TBT of no greater than 10 parts per trillion (ppt) in marine water and 26 ppt in fresh water. State officials, however, are recommending more stringent maximum levels of 6 ppt and 20 ppt.

Although the Mussel Watch measures TBT in mussel tissue, for which there are no standards, the draft report mentions that the compound has been tested at between 10 and 920 ppt in San Diego Bay waters.