Heavy metals in the chemical make-up of the synthetic turf fields in Westport could be leaching into the town's surface waters, possibly posing a threat to aquatic life. However, there is no system in place for measuring chemical toxicity in stormwater runoff from those fields.

The town has been alerted to the possibility of that toxic threat in the release late last month of a 19-month, multi-agency state study of the safety of four such fields at different locations in Connecticut.

As reported in the Westport News last week, the study found no elevated risk from the chemicals to players on the fields, as well as no threat to drinking water from the runoff.

The state Department of Environmental Protection (DEP), which did the water sampling, also emphasized that what it called "acute toxicity," the level particularly injurious to plants and fish, was not found in all the samples taken from the fields. Nevertheless, the environmental agency came to the conclusion in the study that "there is a potential risk to surface waters and aquatic organisms associated with the toxicity of stormwater runoff from artificial turf fields."

Reached for comment Friday about on the overall import of the state study, Westport Parks and Recreation Director Stuart McCarthy said that he was pleased with its positive findings about the safety of the fields for players, but that it came as no surprise.

"This is what we expected, based on all the information available about the fields, but it's good for the residents of Westport," he said.

McCarthy said the fields were designed with "retention structures" to prevent rubber granules, which provide impact-cushioning for the players, from draining off the fields.

"We have no involvement in the monitoring of water," said McCarthy.

Questions about the safety of the fields have focused on the rubber granules, especially after testing by the Connecticut Agricultural Experiment Station in the summer of 2007 had demonstrated the out-gassing and leaching of a number of volatile chemical compounds from the granules under relatively benign laboratory conditions.

According to the environmental report in the state study, three of the eight samples of stormwater, taken from points where the runoff could come only from the fields, had acute levels of metal concentration, but only in zinc on a consistent basis.

"Metal concentrations in excess of the acute aquatic life criteria for more than one hour could cause mortality in the more sensitive organisms in the receiving surface waters," the report states, indicating that it would be the acute criteria that would be most relevant for monitoring the intermittent impact of stormwater on the turf fields At the same time, the samples were found to have levels of copper, barium, iron, aluminum and vanadium, which exceed the state's "chronic aquatic life criteria" that go beyond the acute criteria applied to stormwater.

"Average metal concentrations which exceed the chronic life criteria for more than four days are expected to impact the ability of organisms to survive, reproduce or grow," the report states, adding that this would likely not apply to stormwater runoff.

Westport Public Works Director Stephen Edwards said that his department's role in directly monitoring water quality is limited to the implementation of conditions set by the Planning and Zoning Commission in its approvals of construction and renovation projects.

"We provide technical review of those requirements," Edwards said, citing as an example the construction specifications of the Family Y's expansion project at its 30-acre Mahackeno site.

DEP spokesman Dennis Schain said in a telephone interview Monday that municipal public works departments routinely manage stormwater drainage systems under general state permit guidelines, but that this would not apply to turf fields.

He contrasted turf field runoff with the discharge of water from factories and waste treatment centers that operate under specific state permit guidelines and requirements.

Schain said that the monitoring of run-off is an "emerging area" of regulation and that both his agency and the U.S. Environmental Protection Agency would be looking into the issue more in the future. He conceded, however, that there is not a high level of detail available on the impact of metals on watercourses and waterways.

In a telephone interview last Friday, Alicia Mozian, Westport's conservation director, said that her department does not have protocols for testing for metals in surface water. "They deal mostly with nitrogen, phosphorous and coliform bacteria," said Mozian.

Nothing was mandated in the state study that would require a particular response from municipalities, school systems and private owners of turf fields, but the environmental report does list a number of possible responses.

The environmental agency suggests stormwater treatment measures, such as treatment wetlands, wet ponds, infiltration structures, compost filters, sand filters and bio-filtration structures, as ways of mitigating the potential excess of zinc from the fields.

"Individual artificial turf field owners may want to evaluate the stormwater drainage systems at the fields and the hydrologic and water quality characteristics of any receiving waters to determine the appropriateness of a stormwater treatment measure," the report states.

The DEP is available for consultation with entities that want to be responsive to the environmental issues outlined in the state turf study, according to Schain.