Mercury down 32% in fish near Mass. incinerators

Seven years after Massachusetts enacted the nation's toughest mercury emission laws for incinerators, amounts of the toxic metal have declined by 32 percent in a signature freshwater fish caught near some of those facilities.

A significant amount of the state's inland fish remain unsafe for a large portion of the population, but state officials and environmental advocates say they are stunned by the dramatic turnaround in yellow perch from lakes near a cluster of incinerators in the northeast corner of the state.

State officials now estimate the improvement in yellow perch is about half of that needed to make the fish safe to eat. And good news for perch -- used as an indicator species because it accumulates high levels of mercury -- also means good news for other lake fish across Massachusetts.

However, state officials said much more needs to be done. They could not estimate when it will be OK to lift a strict warning for women of childbearing age and children about eating fish from the state's lakes and streams.

''We weren't expecting to see such drastic reductions in such a short time frame," said Arleen O'Donnell, deputy commissioner for the state Department of Environmental Protection. ''This is really significant because this is a cumulative toxin -- the thought was it took a long time to get this high in the environment and it was going to take a long time to reverse it."

The 32 percent average decrease in mercury occurred in nine lakes in the northeast corner of Massachusetts, home to a cluster of incinerators. Yellow perch from lakes elsewhere in the state recorded a 15 percent drop on average.

Mercury, a naturally occurring element, can cause severe neurological damage in children and fetuses. It is released into the air from incinerators and coal-burning power plants and then falls to the ground, where much of it winds up in waterways. The metal eventually builds up in larger fish at the top of the food chain, including yellow perch and largemouth bass in freshwater, and tuna and swordfish in the ocean.

Federal officials in recent years have estimated up to 600,000 children may be born in the United States each year with neurological problems stemming from mercury exposure in the womb.

New England has long been a hot spot for mercury contamination because of its many power plants and incinerators, and its location downwind from plants in the Midwest. But it is the northeast corner of Massachusetts that has long been one of the most mercury-contaminated regions in New England, brought on by pollution during the Industrial Revolution and the more recent construction of numerous incinerators. In the past, some fish in the region's lakes had mercury readings five times higher than levels considered safe to eat by the federal government. However, some residents in the region regularly fish in the lakes to supplement their diet, despite warning signs posted in many places.

The mercury decline appears to stem from two efforts that began in 1998. First, the Department of Environmental Protection began requiring the state's nine trash incinerators to scrub or remove 85 percent of the mercury emitted from their smokestacks. Old batteries, thermostats, thermometers, and fluorescent lights all contribute to the emissions.

Today, only seven incinerators remain, and they scrub about 90 percent of the mercury. Incinerators continue to operate in North Andover, Haverhill, Saugus, Rochester, Millbury, Springfield, and Pittsfield. (Fall River and Lawrence incinerators have closed.)

Second, the state once had 240 medical waste incinerators that burned items such as mercury thermometers, but those incinerators began closing at a greater rate as federal and state rules tightened. The last one closed in 2003.

The Department of Environmental Protection, which has been testing mercury in freshwater fish since 1984, picked 17 lakes to monitor, choosing about half in Northeast Massachusetts. The department examined yellow perch and largemouth bass, both of which accumulate mercury and are fished recreationally. While the average was 32 percent in Northeast waterways, in Baldpate Pond in Boxford yellow perch mercury levels declined 61 percent. Less dramatic yet significant changes also were recorded for largemouth bass, with fish in 11 Northeast lakes recording a 25 percent decrease in mercury on average and bass from the rest of the state showing a 19 percent decrease.

The state's mercury news is likely to get even better as strict rules for power plant mercury emission are phased in. Last week, the state Senate followed the House's lead in passing a bill to phase out mercury in thermostats, autos, and electrical switches. The bill is expected to go before Governor Mitt Romney later this year.

And later this month, a law goes into effect that requires dentists to capture mercury leftover from patients' fillings.

Today, only about one-third of the mercury deposited in Massachusetts comes from in-state sources; the rest travels here on air currents from power plants and other sources both in the United States and around the world.

That may be changing, too. Frustrated by new federal mercury emission rules critics say don't go far enough to protect public health, at least nine states are considering legislation to more strictly control mercury.

The US Environmental Protection Agency allows dirtier power plants to buy air pollution credits from cleaner ones, a mechanism intended to use market incentives to reduce mercury pollution 69 percent by 2018. Critics say that technology exists to reduce mercury even more at a low cost -- and that the trading scheme will cause hot spots of mercury contamination near power plants that pay for the right to pollute.

Some EPA critics said the Massachusetts fish data, along with similar research in Ohio and Florida that shows high levels of mercury in the environment near smokestacks, support their hot-spots argument. Massachusetts has joined 10 other states suing the federal government over the rules, saying they violate the federal Clean Air Act.

''What's interesting is that these results undermine the whole assumption of the federal mercury control program," said Paul Miller, deputy director of the Northeast States For Coordinated Air Use Management, a nonprofit association of state air quality agencies. ''It shows local controls have local impacts."

An EPA spokesman said last week the agency had not seen Massachusetts' results and needed to study the issue more. If hot spots were occurring, he said, the trading problem would solve the issue because it provides a financial incentive for the dirtiest power plants, which would probably be contributing the most to any local problems, to reduce the pollutant.

In Massachusetts, state officials say many more years of data need to be gathered before it is safe for pregnant women and children to eat freshwater fish. And they say the problem with seafood, where mercury can build to alarming levels in popular fish, won't be solved by state or federal regulations. Much of that pollution comes from global sources that have few, if any, limits on emissions. ''This is a milestone because it says mercury contamination is a solvable problem," said Michael Bender of the Vermont-based Mercury Policy Project, which works to reduce mercury in the environment. ''But we have a long way to go."

Beth Daley can be reached at bdaley@globe.com