What to do about mercury

BUILDINGS ARE COLLAPSING under the ice and I have no idea how to get rid of the glacier where the sidewalk used to be. So worrying about mercury coming from the Lafarge cement plant across the Hudson River is low on my list of concerns. Besides, something measured in parts per billion seems insignificant compared to all the other toxic substances that have crossed my nostrils.

And still, it caught my attention that a Ph.D. research associate from the Harvard School of Public Health found that about 10% of 172 subjects tested within a 10-mile radius of the Lafarge cement plant in Ravena, across the river from the northern tip of the county, had elevated levels of mercury in their blood and hair.

Put the point of a compass on Ravena, mark the 10-mile area, and on the east side of the Hudson that covers essentially all of the Town of Stuyvesant, the villages of Kinderhook and Valatie, the hamlets of Niverville and North Chatham and most of the south end of the Town of Schodack in Rensselaer County. And because the wind flows in a generally eastward direction, a lot of the harmful materials the plant emits float over northern Columbia County.

Does one study of 172 people who volunteered for testing reveal whether the plant represents any sort of health threat? The researchers who met with the public last month to outline what they have learned were very clear about the limits of their knowledge. They found some evidence that some people had more of some substances in their bodies than some previous studies would have predicted. The sum of all those “somes” leads to a reassuring answer: They don’t know.

Why is that reassuring? Because that’s the way science is supposed to work. Conclusions about the existence — let alone the extent — of local health risks from mercury exposure have to be based on factual observations and valid data carefully analyzed and subjected to the review of other experts. All that these Harvard scientists can say right now is that they think there’s enough tantalizing data to make further study worthwhile.

Among the things they don’t know is where the mercury and other potentially harmful substances they detected come from, something further tests could help determine. Some folks who live close to the Lafarge plant suspect that the plant is the source. That’s an understandable conclusion given that only a few years ago the plant’s own data revealed it was the second largest emitter of airborne mercury in the state. But as logical as it sounds to make the connection between Lafarge and human mercury levels, doing so is not science. Anyone who believes in the work of the Harvard researchers must also accept that their data do not implicate the plant.

But other scientific studies show that releasing large amounts of mercury into the air does pose a threat to human health and the environment. And that finding becomes significant because Lafarge has proposed a major upgrade to its Ravena plant. It plans to install new, more efficient equipment capable of manufacturing considerably more cement that it can produce there now. The upgrade will include improved emission controls that would reduce the amount of pollution released into the air per unit of cement. But if the overall amount of cement made there also increases, it’s not clear whether the overall pollution from the plant will decrease.

In boom times, the government might have required the company to fund further studies of the health impacts of plants like the one in Ravena. But in this economy that option is off the table. The economy also limits the ability of the state Department of Environmental Conservation, which is reviewing the Lafarge upgrade proposal, to conduct prolonged monitoring designed to detect the release of pollutants at levels already known to cause harm to humans, especially children.

One thing government can do is consult with researchers like the ones from Harvard to determine what data they expect to need in the future as they pursue further health studies around the plant. The DEC should then require the company to make all those data public without delay. The plant’s permit should rest on in part on ready access to those data.

The Lafarge plant has the right to operate in compliance with the law. But that right must be balanced by the right of the public to know more about what health threats we may face.  

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