160 Toxics Per Day Flow Into Santa Monica Bay, Study Finds : Pollution: Urban runoff into the ocean deserves more research, says a report commissioned by an environmental group. Statewide posting of warning signs about the danger of swimming near storm drains is being sought.

An estimated 160 toxic chemicals--many of them known or suspected carcinogens--flow daily into Santa Monica Bay through the storm drains that capture urban runoff, causing potential danger to humans and marine life, according to an environmental study released Tuesday.

Although the bay, the most popular Southern California beach destination, has long been known as a site of some toxic contamination, the study identified a wider range of chemical pollutants than had been analyzed before.

“As this study shows, there are very real storm water risks to users of the bay and the ecology itself, which must be evaluated and quantified if we are to properly inform our citizens and protect Santa Monica Bay,” said Robert H. Sulnick, executive director of the American Oceans Campaign, an environmental group that commissioned UCLA to conduct the study.

The findings are the latest salvo against the widespread problem of ocean pollution from urban runoff. Although the main single sources of pollution to the bay--such as sewage plants--have largely been remedied, storm water pollution is an area that has had little study and even less prevention, scientists and environmentalists say.

One of the main findings of the report is a high level of polycyclic aromatic hydrocarbons, also known as PAHs, carcinogens that are byproducts of incomplete combustion and may emanate from auto exhaust, used motor oil and tires. A wide range of PAHs were found in levels above those allowed in the California Ocean Plan, which sets standards for California’s coastal areas.

“If PAHs are well above Ocean Plan standards, shouldn’t we care about them, if humans and marine life are directly exposed to urban runoff, which we are?” asked Mark Gold, staff scientist for Heal the Bay, another environmental organization. “This brings out the need for the Ocean Plan to apply to urban runoff as well. It’s not clear that it does.”

To John Froines, a professor of toxicology at the UCLA School of Public Health and the lead scientist in the study, the presence of PCBs, or polychlorinated biphenyls, in levels greater than allowed under the Ocean Plan is also of great concern. PCBs are known carcinogens and cause reproductive problems. They can enter the body through contact with the skin and also concentrate in fish that are later eaten by people.

“We don’t know their origin,” Froines said, “or why they’ve come into the storm drains.”

The study sampled water from five of the bay’s 64 storm drains over a six-month period and found what Froines characterized as probably 10% of the chemicals that flow from drains into the bay.

“What this study shows is that there’s a lot more there that needs to be characterized, but also that we’re only seeing part of the problem,” Froines said.

Although Los Angeles County beaches have signs at most storm drains warning of the dangers of swimming closer than 100 feet, the American Oceans Campaign is asking for statewide warnings--large and bilingual--about swimming near drains. The group also is urging the state to come up with a management strategy for pollution from urban runoff.

Assemblyman Terry B. Friedman (D-Brentwood) this week wrote to Molly J. Coye, director of the state Department of Health Services, informing her of the study and requesting that signs be posted at beaches throughout the state.