Weeds strategy at issue

State officials will make their case tonight to the Natick Conservation Commission for using chemicals to treat fast-growing weeds that are threatening to clog Lake Cochituate. But they're likely to face plenty of opposition from residents.

''There are a number of unknowns, and this is a very big step to put chemicals in because once you put them in, you can't take them out," said Carole Berkowitz, the chairwoman of Protect our Water Resources, a group that is fighting to prevent the use of herbicides in the lake.

''The risk is too great. We have other alternatives, and we need to try them first," she said.

Berkowitz said her group is concerned about what the chemicals could do to the lake water and worried that chemicals will seep into the ground and contaminate town drinking water wells located nearby.

The Massachusetts Department of Conservation and Recreation is seeking approval from the conservation commissions in Natick, Framingham, and Wayland, communities that border the lake, to combat invasive aquatic species.

The state wants to use herbicides in the areas most heavily impacted by the milfoil weed.

After the use of chemicals, the state would follow up with nonchemical methods, such as pulling the weeds by hand; releasing milfoil weevils, aquatic insects that feed on milfoil; and suction harvesting -- essentially vacuuming up the weeds -- with the help of divers.

The state will present its plan to the Natick conservation board at 7:30 p.m. at Town Hall.

The commission could approve both plans.

It could also just approve the use of nonchemical methods.

Vanessa Gulati, a spokeswoman for the state Department of Conservation and Recreation, said the agency would prefer to avoid using chemicals, but the area taken over by milfoil is too large.

''It's such an extensive area," Gulati said. ''There is just no physical way to go up and pull out all the milfoil. It's several acres. The whole lake cannot be handpicked."

Eurasian water milfoil is a green weed whose roots grow in the sediment at the bottom of the lake and spreads rapidly, getting caught in boat motors, making it difficult to swim, and killing off other aquatic life.

Gulati said the chemicals being used are safe, posing no threat to humans' health, and having no significant impact on wildlife.

''The [federal Environmental Protection Agency] has done extensive testing on these chemicals and says it's safe for drinking water, which is the highest standard," Gulati said. ''We're trusting the research of the EPA."

All herbicides used in Massachusetts must be approved by the EPA after a multiyear process involving 120 separate studies of the potential environmental and public health impact.

Once the EPA has registered a herbicide for a particular use, the state Department of Environmental Protection's Office of Research and Standards carries out its own review, along with the Massachusetts Department of Agricultural Resources Pesticide Board.

Three invasive species of aquatic plants were discovered in Lake Cochituate's South Pond in the summer of 2002. The milfoil requires the most attention because it is the most aggressive.

The state sought to treat the lake with chemicals then but the Conservation Commission's approval was appealed by citizens.

The state is now coming back with a modified plan, using different chemicals.

Gulati said it's critical for the state to use the chemicals.

''The future of the lake is that it will be completely taken over by the milfoil," Gulati said.

''The people on the lake won't be able to swim because the milfoil will take over. It will also be difficult to use a boat because it gets caught in the motors."

But opponents say there are too many unknowns when it comes to using chemicals.

Instead, Berkowitz's group would like the state to try the other methods first. And the group is pleased that the state is presenting two options for the Conservation Commission to consider.

''The community finally has a choice and can exercise its voice," said Paul Schramski, a community organizer with the Toxics Action Center, which has been working with Protect Our Water Resources.

''We want to be given the option of some other approved methods."

Although the Conservation Commission approved the use of herbicides in the past, chairman Matthew Gardner said members will not take that into consideration.

''We're going into this to be as objective as possible," Gardner said. ''The fact that the previous commission approved it is irrelevant. We're looking at this with fresh eyes."

Gardner said it is clear something needs to be done to save the lake.

''Our job is going to be to take a close look and see what the options are to make the best decision for the lake and the water supply," he said.