Pond yields a big can of worms

For much of the past two decades, Westwood has welcomed the new year with a crackling fireworks display over Buckmaster Pond. But just as the holiday often takes a toll on excessive revelers, those celebrations may have left the pristine water slightly polluted, a kind of environmental hangover.

Recently released test results found excessive amounts of perchlorates, waterborne toxins used in fireworks and other explosives, in the water.

The test was done for neighboring Norwood, which has owned the rights to the pond for more than a century, even though the pond lies entirely in Westwood. Since summer last year, Norwood has been pumping water from the aquifer to test it as a possible secondary drinking-water source.

The discovery of the toxins complicates Norwood's search for a backup water supply by potentially making the cost of drawing water from the pond prohibitive.

Norwood's general manager, John Carroll, said the yearly fireworks are the logical cause of the contamination.

"It's a chemical found in explosives, and fireworks are the only known explosive that's been used at the pond," he said.

Westwood officials were startled to learn that their celebrations apparently had led to water pollution.

"We were definitely caught by surprise," said Town Administrator Michael Jaillet. "We had no indication this could cause a problem."

Jaillet said that the Norwood selectmen had approved the fireworks several years ago and that he hoped the situation could be "resolved amicably."

"It's an odd situation, but I hope it's clear we were acting in good faith," he said.

Carroll said Norwood has no plans to pursue legal action against its neighbor. Norwood selectmen apparently did approve the celebration one year, he said.

Meanwhile, as Norwood continues its water search -- the Massachusetts Water Resources Authority has discussed building an emergency water supply for the area, but only preliminarily, said Carroll -- Westwood will move its New Year's pyrotechnics to Westwood High School.

Buckmaster Pond was abandoned as a source of drinking water in the 1950s when the town began receiving water from the Quabbin Reservoir. Recent testing has involved reactivating the old wells.

In July, the state adopted the nation's strictest drinking-water limits on perchlorate, a chemical produced naturally but also found in explosives. It can impair the function of the thyroid gland, which regulates the body's metabolism. Pregnant women, infants, and people with hypothyroidism are most susceptible.

Ed Coletta, spokesman for the state Department of Environmental Protection, said the tougher standards arose from concern over an aquifer in Bourne that was probably contaminated with perchlorate from the Otis Air National Guard Base.

Buckmaster Pond has a long history of trouble. Controversy over its use spurred West Dedham residents to secede from Dedham and establish Westwood. According to local accounts, Dedham ceded its rights to the pond to Norwood in 1885, believing Buckmaster was too far from the town center to be convenient. That alienated West Dedham residents and motivated them to break away.

This month, the news of the contamination sparked mixed emotions among Westwood residents. Most had opposed the wells being reactivated, worried that their popular fishing and skating spot might be drained.

Laura Stanton, who lives on the pond, said she was skeptical that a once-a-year fireworks display, one that doesn't exactly rival the Fourth of July extravaganza along the Charles River, was the culprit, though she acknowledged that it "makes for a great story."

Stanton expressed relief that the contamination might scuttle Norwood's plans, which she feared would turn a lovely pond into a "mud flap with a chain - link fence around it." But she said its distance from Norwood was probably going to make it too expensive anyway.

"Economically, it never made a whole lot of sense," she said.

Buckmaster neighbor Patrick McQuillan also had mixed emotions about the pollution.

"We want the pond to be clean, but we'd also like it to stay here," he said. "So we'll take it however it comes."

Peter Schworm can be reached at schworm@globe.com.