WILMINGTON — The proposal for Titan America to build a new cement manufacturing plant along the shores of the Northeast Cape Fear River near Wilmington brings with it the potential for increased air and water pollution to the southeast coast, as well as increased risks to human health from airborne toxins. What has had little exposure thus far is the strong likelihood of serious pollution impacts to fish and wildlife.
Titan will utilize a coal-fired kiln to burn limestone, producing widespread air and water pollution. Pollutants in particular from this source that will especially impact wildlife include mercury, arsenic and selenium.
During 2004-2005 Dr. Mallin's laboratory was funded by the state Attorney General's Office to conduct a survey of potential pollutants in the flesh of freshwater fish and clams in the Cape Fear, Black, and Northeast Cape Fear River basins. The findings were surprising in that they showed that several pollutants exceeded the U.S. Environmental Protection Agency and the state health director's standards for safe human consumption. These pollutants included mercury, arsenic, selenium, cadmium, PCBs and several pesticides. The first three, as mentioned, are byproducts of coal burning, and coal-burning power plants are the largest source of mercury to our atmosphere.
Mercury exists in several forms, but even benign forms can be converted to the most toxic form, called methyl mercury. One could not find a more ideal location for the conversion of airborne mercury to methyl mercury than the swampy forests along the banks of the Northeast Cape Fear River.
The conversion to the toxic mercury form is most effective in places where the water is acidic, bacteria are abundant and there is plenty of dissolved organic carbon, the natural material that gives the river and creek water its dark coloration. Once in the water, and in the sediments under the water, methyl mercury enters the food chain. It is taken up by microbes, algae and other plankton, which are eaten by aquatic insects, snails and clams, which are eaten by fish, which are eaten by larger fish, and so on.
At each step up the food chain mercury becomes more concentrated, a process called biomagnification. Fish, of course, are eaten by birds, forest wildlife and humans.
Unfortunately mercury levels in several species of our freshwater fish and clams are already at levels exceeding standards for safe consumption. Thus, adding more mercury to the mix will cause more fish farther down the food chain to be added to the non-consumption list.
Arsenic and selenium are byproducts of coal burning that are also at levels in freshwater fish and clams that are unsafe for eating. Not only are these polluting metals a danger to humans, they are at or near levels in the fish known to pose a danger to the wildlife themselves, such as reduced reproduction or higher disease susceptibility. We need to remember that while humans can avoid eating pollutant-contaminated fish, the birds, mammals and alligators in our waters cannot.
The State of North Carolina is required by the U.S. EPA to prepare a plan called a total maximum daily load (TMDL), which means our state regulatory agencies have to reduce the mercury entering our streams and wildlife. Adding to the load by allowing increased air and water pollution from a new cement plant is a big step backward.
A healthy step for our state's environment was announced recently by Progress Energy, which is taking the initiative to replace the Sutton coal burning power plant and other coal-burning facilities with power generation that uses natural gas. This is a much cleaner fuel and will lead to less air and water pollution, as well as a reduction in global warming-causing greenhouse gases to our atmosphere. Let us follow that positive lead by further reducing our pollutant load on our wildlife, rather than increasing it.
Michael A. Mallin is a research professor at the Center for Marine Science at UNC Wilmington. Lawrence B. Cahoon is a professor in the Department of Biology and Marine Biology at the university.
