WASHINGTON (The Boston Globe) - Recently issued government guidelines are inadequate to protect fetuses and newborn babies from the harmful effects of mercury in seafood, according to a report released Thursday by a pair of advocacy groups.

The study by the Environmental Working Group and the U.S. Public Interest Research Group concludes that as many as one in four pregnant women could endanger the long-term development of their children if they follow the dietary guidelines issued by the US Food and Drug Administration at the start of this year. The groups also identify 13 fish that pregnant women should not eat - three times the number currently identified by the government.

The report, which drew criticism from the government and from food processors, was also critical of federal and state government monitoring of mercury in fish.

The study cited Massachusetts as one of two states with sufficient notifications in place regarding mercury levels in fish.

"If American women at this varied diet of FDA's recommended 12 ounces of fish per week, more than one-quarter of all pregnancies every year, or about a million pregnancies, would be exposed to potentially harmful levels of methylmercury for over a month of the pregnancy," said Jane Houlihan, the Environmental Working Group's research director. "And 20,000 of those children would be exposed to a high level of methylmercury through the entire pregnancy."

FDA representatives did not return phone calls Thursday. In addition to the four species of fish that the agency already said that women of child-bearing age should avoid, the study cited nine other types of fish and seafood, including fresh tuna, sea and largemouth bass, and Gulf Coast oysters.

The study found a second group of fish that pregnant women should not eat more than once a month that included canned tuna, mahi mahi, and eastern oysters.

The report also identified nine fish and seafood they recommended, including farmed trout and catfish, shrimp, fish sticks, summer flounder, wild pacific salmon, croaker, haddock and blue crab.

A food processors group disagreed with the report, arguing that the government has greater credibility than the two advocacy organizations.

"We believe that the FDA has made decisions based on very strong science," said Timothy Willard, spokesman for the National Food Processors Association, which represents the food processing industry. "They have greater expertise on health and safety issues and we find them a very credible source of information."

Fish is widely considered to be an excellent source of nutrients, but concerns have long existed about levels of mercury contamination.

The FDA in January issued guidelines on mercury in fish for women who are pregnant or may become pregnant. At that time, the agency said that those women, and young children, should avoid eating shark, swordfish, king mackerel, or tilefish. Otherwise, the agency said, women can eat up to 12 ounces of cooked fish weekly.

But the two advocacy groups say that the agency's study was flawed because it's risk assumptions are for a 150-pound male with no prior level of mercury exposure.

The study uses computer modeling to evaluate the risk for a wide range of women. The two groups compiled data on mercury contamination of fish from seven federal, state and other governmental sources, eventually compiling a database of more than 50,000 records. They used those records to determine which fish generally have the lowest mercury contamination and which have the highest.

The report comes as the administration considers whether to uphold a Clinton plan regulating mercury emissions from coal-burning power plants, a potential source of the contamination.

Copyright 2001 The Boston Globe. All rights reserved.