The amount of toxic chemicals released from major industrial facilities in the Chesapeake Bay watershed declined by more than half since 1988, bringing the Bay Program close to meeting a goal contained in the toxics reduction stnrategy adopted last year.

The watershed's 52.4 percent reduction outpaced the national average, according to the data gathered by the EPA's Toxics Release Inventory. Across the United States, toxic chemical releases declined 42.7 percent between 1988 and 1993.

But the figures also show that the watershed is short of the reductions being sought for a group of "Toxics of Concern" which are thought to pose the greatest risk to Bay species.

The latest figures for facilities in the Bay's 64,000-square-mile drainage basin were compiled by the EPA's Chesapeake Bay Program Office to help track progress toward meeting commitments in a new "Basinwide Toxics Reduction and Prevention StrategyÓ tha" was adopted by the Executive Council last year.

The Executive Council is the top policy-making body for the Bay cleanup effort, including the governors of Maryland, Virginia and Pennsylvania; the mayor of the District of Columbia; the EPA administrator; and the chairman of the Chesapeake Bay Commission, a panel representing the legislatures of the three states.

While that strategy set forth a number of objectives, almost all the quantifiable reductions were tied to TRI data, including a 50 percent reduction in chemicals released from industries required to report TRI data; a 75 percent reduction in TRI-reported releases from federal facilities in the watershed; and a 75 percent reduction in Toxics of Concern releases based on TRI data. All those goals are to be achieved by the turn of the century.

The figures show that 180.2 million pounds of TRI chemical releases were reported in the watershed in 1988. By 1993, the most recent year for which figures are available, releases declined to 85.7 million pounds.

While on the surface that would appear to meet the goal, it in fact falls short. That's because the EPA this year began requiring industries to report releases of an additional 286 chemicals. As a result, no reductions have yet been made for that group. With the addition of those chemicals, industries are required to report releases of about 650 substances.

Progress toward the Bay ProgramÕs other TRI-related goals is uncertain. Federal facilities, which are to make a 75 percent reduction in chemical releases, did not have to compile such data until 1994, so their releases have not yet been included in the EPA's annual report.

And while releases of Toxics of Concern have declined from 1.6 million pounds in 1988 to 730,644 pounds in 1993, only eight of those 14 chemicals, which are considered to pose the greatest threat to the environment, were on the reporting list prior to this year. Another four were added this year, and two remain unlisted.

For the Toxics of Concern included in the 1993 data, naphthalene releases were down 95 percent from 1988; PCBs were down 89 percent; cadmium was down 49 percent; chromium was down 21 percent; copper was down 70 percent, and lead was down 7 percent. No releases were reported for mercury or chlordane.

This year, industries will have to begin reporting releases of atrazine, benzo[a]anthracene, benzo[a]pyrene and tributyltin. There are no reporting requirements for the remaining two Toxics of Concern, fluoranthene and chrysene.

The Toxics Release Inventory stems from the 1986 Emergency Planning and Community Right-to-Know Act. It requires manufacturers to report releases of listed chemicals if they have 10 or more full-time employees and process more than 25,000 pounds, or use more than 10,000 pounds, of any listed chemical during the calendar year. Since 1988, the number of facilities reporting TRI data in the watershed has ranged from 845 to 974. Because of fluctuating production levels and other factors, some manufacturers do not have to report every year.

The TRI list is not a comprehensive measure of the amount of toxics entering the environment. It does not, for example, measure car emissions, discharges from utilities, releases from small businesses and manufacturers, pesticides used in agriculture or discharges from sewage treatment plants.

Jackie Savitz, a staff scientist with the Chesapeake Bay Foundation, noted that EPA studies of water discharge permits have found that only about 10 percent of the toxics entering waterways are counted in the TRI data. That was largely due, she said, to the fact that wastewater treatment plants are not req uired to submit TRI data.

On the other hand, the vast majority of toxics releases are into the air, not the water, and almost all major manufacturers are required to report their releases.

Rich Batiuk, toxics coordinator with the EPA Bay Program's Office, said it was unclear exactly what percentage of all toxic emissions are captured by the TRI requirement. Many state and industry officials, he said, believe that it may include the majority of all toxics releases.

Whatever the case, the EPA has touted TRI as a valuable tool in encouraging emission reductions. Because the facility-by-facility data is publicly reported, manufacturers often make voluntary reductions as a goodwill gesture to the local community.

Many of the TRI numbers are based on estimates, and some of the reductions over the years have also been decried as "paper reductions" that resulted from changes in the way estimates were made.

In some cases, huge errors in the data have been found by government auditors, but EPA officials say the numbers have become more reliable over time.

In fact, Batiuk noted that while some of the past estimates may have been high, some also may have been too low. "A number of [industries] have said they underestimated their 1988-89-90 loadings, and their reduction percentages would be even sharper if they were able to go back with the techniques and approaches they have now and look at their data," Batiuk said. "They feel that they were underestimating their previous loadings."

By encouraging overall reductions in toxics releases, the Bay Program strategy adopted last year seeks to reduce potential risks to human health and Bay species. While severe contamination problems in the Bay are limited to a few areas, most notably portions of the Patapasco, Anacostia and Elizabeth rivers, a multiyear review found that low levels of toxic chemicals could be found throughout the Bay, though their impact was unclear.

Toxics reductions measured by the TRI data are one of the key elements of that strategy, which sets an ultimate goal of a "Bay free of toxics."

As an incentive to make voluntary reductions, Batiuk said the Bay Program plans to begin a program to recognize facilities that have made large TRI reductions.

TRI data, including facility-specific and chemical-specific listings, are available to the public. For information, contact the EPAÕs Emergency Planning and Community Right-to-Know Hotline, at 1-800-535-0202.