Second in a two-part series

By M.E. Jones

Correspondent

AYER -- People of Ayer Concerned about the Environment hasn't exactly been dormant recently, but it has been less visible than it once was. Now, the watchdog group is re-entering the public arena to tackle an issue it thinks people should be informed about.

Sparked by recent news that the Army plans to close a treatment facility that is pulling arsenic out of the Shepley's Hill landfill site, PACE held a public meeting with longtime PACE consultant Richard E. Doherty of Engineering & Consulting Resources Inc., giving the presentation.

The few who attended -- besides PACE members -- got an expert's virtual guided tour, including the background and history of Shepley's Hill landfill.

The presentation also cited future plans and sketched the public's role -- what you can do to take part and stay informed.

Arsenic is at the crux of the issue. A strong poison, it occurs naturally in some types of rocks, including some that are common in this area. Used in the past as a wood preservative, it is also found in pesticides, lead alloys and semiconductors, all of which probably went into the landfill in various forms, from empty bug spray cans to dead computers to discarded military equipment.

Test wells at the Shepley's Hill landfill site show arsenic concentrations up to 6,000 parts per million in the groundwater, which is dramatically higher than acceptable levels and much greater than concentrations typically found at other landfill sites.


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The standard for arsenic in drinking water is 10 parts per billion.

Nobody drinks the water from Plow Shop Pond, Grove Pond or Red Cove, which gets direct runoff from the landfill site. But wildlife could be affected and PACE fears that over time, contaminants from the pond water could end up in municipal wells or people's backyards.

To address that problem, the Army is constructing a wall.

All well and good, says PACE, as far as it goes. But it might not be enough.

Future plans on the group's to-do list call for continued monitoring at the site to determine if the wall is effective. In the meantime, the arsenic treatment plant would continue to operate and would not close, per the Army's current intent.

North of the landfill, the Army's proposed solution is dispersion, allowing arsenic detected in those areas of Devens to "come out of solution" on its own, Doherty said. The process is known as "monitored natural attenuation," or MNA.

It's not an unsound approach, he said, but the Army's aim to close the treatment plant is another matter.

And the Army claims the arsenic problem is rock-related anyway and thus not the fault of military-era dumping in the first place.

As the Army decides whether to close the plant, now is the time for public involvement, PACE members said. Citizen input could "tip the scale" in a different direction.