SAN DIEGO — Pregnant women should not eat fish caught in the San Diego Bay, and other adults should eat what they catch only in moderation, according to the results of a two-year study released Monday.
The $309,000 study, funded by the San Diego Unified Port District and conducted by the county Department of Health Services, found potentially harmful levels of mercury and polychlorinated biphenyls (PCBs), a group of chemicals suspected of causing cancer, in the muscle and liver tissues of the 340 fish collected at four sites around the bay.
Researchers concluded that a person would have to eat 6 ounces of contaminated fish each day for 70 years before an adverse health effect could occur. And they estimated that the cancer risk from eating fish dinners from the bay was roughly comparable to that posed by eating four tablespoons of tainted peanut butter every day. But still, they recommended precautions.
"Don't eat the fish every day that you catch, no matter who you are," said Dr. J. William Cox, the director of the county Department of Health Services, adding that once the state has reviewed the study, the county will likely publish warnings in local newspapers. "We're going to tell them very simply: If you're pregnant, don't eat fish from the bay. . . . And don't eat fish from the bay every day."
Perhaps the most alarming news in the study, however, was that it told only part of the story. Although eight fish species were tested for several pesticides and metals, there was only a limited screening for benzene and toluene, both known carcinogens. And the potential risks of several other chemicals, including toxins such as arsenic, selenium and radionuclides, "have not completely been assessed," the study said.
To fill in these gaps, the study recommended more testing and called for establishing a bay-wide monitoring program to test more species of fish for more poisons. But Gary R. Stephany, the county's deputy director of environmental health services, acknowledged that such a recommendation is unlikely to be followed without more money.
"Right now there is no money set aside any place to do continuous monitoring," he said at a press conference at which county officials, determined not to spark widespread panic, tempered their warnings with exclamations about how much the bay has improved. The bay is not pristine, they said, but it may be cleaner than many other bays of its size. Eating too much bay fish may make people sick, they said, but so might too much red meat.
"Living is dangerous to our health," Cox said. "We as individuals have to make decisions every day of our life in terms of what activity we are or are not going to engage in. Whether we drive the freeway, whether we swim in the bay, whether we eat fish from the bay . . . or whether we eat beef in excessive quantities."
San Diego County Supervisor Brian P. Bilbray, who had swum in the bay over the weekend and said he planned to do so in the future, agreed with Cox. He said his family would alter its eating habits because of the study, but that each San Diegan should be free to make that decision for himself.
"My son will continue to fish in San Diego Bay," he said. "My 5-year-old will probably eat the fish once a week. If my wife was pregnant, I would ask her not to eat it, even once a week, because I'm just inherently paranoid. But I think it's a judgment call that needs to be made by each individual."
Jay Powell, an aide to San Diego City Councilwoman Linda Bernhart and a spokesman for the Environmental Health Coalition, said he was unconvinced that the new study gave San Diegans enough information to make a judgment--so he brought some with him. Sitting in the front row of the audience, he motioned to a small cooler between his feet.
"I didn't just bring my lunch here," he said. "I have three fish from a commercial fisherman in San Diego Bay that have evidence of tumors. And I think that's the bottom line here: How healthy is the ecosystem, how healthy is the fishery in San Diego Bay? And this study doesn't give us that kind of answer."
Later, as Powell displayed the three mullet with growths on their gills and heads, he worried that the county's decision not to post warning signs until the state directs it to may keep fishermen unaware of what they are eating.
"We have people here in San Diego that are consuming the fish for dinner" on a regular basis, Powell said. "We really feel they ought to be aware that there may be risks."
A profile of who eats fish from the bay was included in the study, based on interviews with 369 fishermen. Of those interviewed, only 6% fished on a daily basis, with the majority fishing less than a dozen times each month.