Lower Levels of Pollutants Found in State’s Coastal Fish

When researchers try to explain why a major new study hints at an improved coastal environment, they keep coming back to the fish.

Fewer fish appear diseased, according to researchers who worked on a new study released by the Environmental Protection Agency this week. Livers of certain other sea creatures showed sharp decreases in DDT and PCB concentrations. The pollution-intolerant brittle star has become more abundant in sediments that were once heavily tainted with pollution.

In Santa Monica Bay, one of the most seriously polluted stretches of coastal waters, the evidence from the fish and mud-dwelling creatures indicate a more resilient environment than researchers might have feared.

Overall, the new study suggests that coastal waters, from Point Conception to the Mexican border, are healthier than 10 or 20 years ago.

“You really have to ask the animals how the environment is faring. When we asked the animals, we found little evidence of current impact,” said Steven M. Bay, toxicologist for the Southern California Coastal Water Research Project, which coordinated the study by the EPA and 10 other agencies.

Testing was done along the Orange County coast and around the 4 1/2-mile sewer pipe that releases an average of 240 million gallons of treated sewage daily into the ocean off Huntington Beach. Results throughout the region found elevated contaminant levels around sewer outfalls.

“The Orange County sewer outfall was in good or better shape than any sewer outfall we looked at,” said Stephen B. Weisberg, executive director of the coastal project.

Creatures like the brittle star are considered to be “sentinels” of marine health in a region long known for its offshore DDT and other pollution, researchers said.

Problems persist, particularly with the Santa Monica Bay, where researchers found that mud and sand offshore continue to show concentrations of DDT, PCBs, eight trace metals, organic carbon and nitrogen that are significantly higher than in other areas.

In fact, 49% of the bay’s sediments exceeded federal thresholds for contamination. By contrast, only 7% of sediments from other regions of the coast were similarly polluted.

Yet while sediment pollution was higher in Santa Monica Bay, the health of its biological resources--the fish and mud-dwelling animals that were tested--were similar to those in other areas.

That paradox could mean that low-level effects of pollution are going undetected or that marine creatures are simply adapting to life in a contaminated environment, Weisberg said.

Further research will be needed to determine which explanation is correct, he said.

The bay sediments found to be contaminated are on the ocean floor, with concentrations increasing in deeper water, researchers said. Beach-goers are not likely to come into contact with the tainted sand and mud.

Measurements of Santa Monica Bay’s water quality--dissolved oxygen and water clarity--were similar to those from other regions. The study did not include bacterial surveys, an issue that greatly concerns swimmers and surfers. Such surveys are planned this year.

The pesticide DDT was found in 82% of coastal sediments, making it the most wide-spread polluter. The highest DDT concentrations were on the Palos Verdes shelf, long known as a serious “hot spot” because of flows from a major pesticide plant near Torrance.

DDT was banned in the United States in 1972, but it degrades extremely slowly.

“That’s generally where we found the highest [DDT] levels in sediments and highest levels in fish,” Bay said.

Scientists have paid increased attention to contaminated sediment in recent years because it can poison marine life and taint fish and mussels consumed by people.