In some localities, toxins exist at concentrations high enough to pose potential health risks. These toxins contaminate water, bind to sediments, and potentially bioaccumulate in the tissues of plants and animals. Many toxins, which are detected in the environment, are not due to new input, but due to existing compounds recycling between the water, sediments, atmosphere, and organisms.
Biological uptake patterns may differ among organisms; on the basis of such differences toxins are grouped into 2 categories: non-cumulative and cumulative toxins. Non-cumulative toxins do not increase in concentration in the body, even if the organism is chronically exposed to the toxin. Conversely, cumulative toxins, tend to increase in concentration, and are often associated with a specific tissue, e.g., cadmium tends to increase over time in the digestive gland of blue crabs. Such accumulation may lead to food chain magnification, i.e., the magnification of toxin concentrations across trophic levels when the prey species possesses a physiological mechanism which concentrates the toxin in a specific tissue and the predator consumes large quantities of this prey.
Consumption of blue crabs by humans in the Hudson River is restricted as cadmium can cause impaired kidney function even at relatively low concentrations. Higher Cd accumulation in humans can potentially lead to other serious health risks including: bone deformities, cardiovascular and immune system deficiencies, central nervous system disorders, and lung cancer (Anonymous 1994, EPA bulletin). Beyond the risks to human health, high toxin contamination also poses ecological concerns by threatening indigenous wildlife and plant species. Toxin contamination also imposes economic and other societal effects as remediation is often very costly (beyond a local county or state budget) and the individuals involved in policy decisions differ in opinion as to the best course of action in remediation efforts.
Twenty-seven years of nickel-cadmium battery production left Foundry Cove contaminated with 179 metric tons of cadmium. In 1983, a remedial investigation of Foundry Cove by the EPA and the NY State DEC, resulted in EPA declaring Foundry Cove a "superfund site" and millions of dollars were allocated to the cleanup.
The Marathon Battery site encompasses wetlands, archaeologically and historically sensitive lands (Indian artifacts and Civil War relics were discovered at the site), a warehouse facility, and contaminated residential areas (yards). The EPA designed specific treatments to address the effects of extensive metal contamination.
Foundry Cove Timeline 1979-1995
Using Superfund authority, and with the advice of scientists and residents, EPA designed the following remediation measures: (1) dredging, draining, and treating contaminated sediments and replanting acres of marshes along Foundry Cove, (2) excavating and treating contaminated soil in an underground vault on the plant property and tearing down plant buildings and processing towers, (3) decontaminating and recycling books stored at the plant, and (4) excavating contaminated soil from residential yards near the site and lanscaping these yards. The EPA settled with the former battery plant owners to conduct the cleanup, estimated to cost $91 million. The responsible corporations also agreed to reimburse EPA $13.5 million for past cleanup and future oversight costs.
In 1992, the cleanup of the plant's interior and the recycling of the contaminated books on the property were completed. Starting in 1993, East Foundry Cove was dredged and the contaminated sediments were hauled away and treated.
Prior to excavation a dike was constructed around the marsh to limit transport of sediments into the Hudson. West Foundry Cove was not dredged since the contamination was less severe than in eastern part of the cove and will naturally be covered by sedimentation over time. Consitution Marsh located in nearby South Cove was not excavated because it received only low levels of metals and since it is a National Audubon Refuge human intervention was deemed an unnecessary risk.
Air photograph of the site during restoration. Note newly dug creeks to maintain flushing and oxygenation. Also note the ring around the site. This was a large rubber bladder that resembled an inner tube. It protected the site from incursions of water as the cleanup and sediment removal proceeded.
Remediation of metal contaminated sediments has important policy implications. Dredging projects produce contaminated sediments which must be disposed and disposal of dredged materials is often problematic. Often such materials are disposed of in sealed underground vaults, but leaching of toxins from such vaults has often occurred, often with drastic consequences, i.e. contamination of the groundwater supply. Since such a remedy was used in Foundry Cove in 1971, groundwater contamination will be monitored for the next 30 years.
A rail spur was also built to haul away treated soil from East Foundry Cove; removal by trucks would have disrupted Cold Spring's historic downtown district and potentially damaged foundations to historic buildings. East Foundry Cove cleanup was completed in 1995.
The top layer of contaminated soil was removed from nearby residential yards and re-landscaped. Wetland replanting efforts have just recently been completed, and the battery plant and processing towers are coming down; the site will soon be an empty lot. Wetland recovery will be monitored for a number of years.
The Foundry Cove site is now owned and supervised by Scenic Hudson, an environmental organization and land trust that works actively to protect important properties in the Hudson Valley especially at the river's edge. The 87 acre preserve is listed on the National Register of Historic Places but also tells a crucial ecological lesson about pollution, evolution, and ecological restoration.
The Hudson River serves as an example of how ecosystem contamination may have broad implications for long-term ecological and economic sustainability. Since the large scale release of Cd and other metals into the Hudson River more than 30 years ago, only recently has the issue of how to clean up the Hudson been resolved. PCB's entered the Hudson about 20 years ago and the issue of how to clean this contamination is still unresolved. Toxic contaminants have led to health concerns, a reduced commercial fishery, debate over the appropriate course for cleaning the river, and damage to the Hudson's public image.
Protecting and managing natural resources and promoting economic growth no longer occupy separate interests. Policy-makers are now realizing the interrelatedness of environmental, economic, and social programs, and balancing these concerns is no simple task. Understanding how contaminants get into the environment, what happens to them once they are there, and what can be done to minimize their impacts or remove them will be crucial to policy-makers forced to balance known (and unknown) risks of contaminants with the need for development.