The fishing and shellfishing industries depend on the health of the estuary's fish and shellfish species, which in turn depend on clean water. Although wetlands are capable of absorbing pollutants, there is a limit to their ability to do so, ecologists say. The pollutants that have the greatest impact on the health of estuaries include toxins emitted by incinerators, power plants and factories. When the toxins seep into sediment in a wetland, they contaminate bottom-dwelling creatures like shellfish.

The Clean Air Act, first passed in 1963, requires that all new and existing sources of air pollution be subject to ambient air quality regulation. New sources, in particular, are required to have stringent emissions control technologies in order to receive operating permits. According to the state Department of Environmental Conservation, stricter emissions standards and numerous emission controls used in all active municipal waste combustion facilities, such as waste-to-energy plants, have resulted in emissions reductions and have contributed to a cleaner environment.

But David Tonjes, assistant professor in the Department of Technology and Society at Stony Brook University, said, "It's not a perfect process. They don't capture all of it. No air pollution control device, whether it's the catalytic converter on your car or whether it's a much more complicated and expensive thing that's put on a smokestack, is going to capture everything. It captures as much as is feasible, economically and technically."

According to the experts, incinerators, including waste-to-energy plans, expel a variety of harmful substances, including organic compounds such as dioxins and furans, as well as heavy metals such as mercury and lead.

Tonjes said, "All of the things that don't burn, such as the metals, are going to end up in the ash. And if those things are of concern, like the metal lead, its concentration is going to be much greater in the ash than it is in the original garbage."