Environmental Cleanup & Restoration: CASE STUDY Foundry Cove in the Hudson River, New York

Foundry Cove is situated in the Village of Cold Spring, in Putnam County, NY, approximately 54 miles north of Battery Park, NYC (Fig 1).

The Marathon Battery Company facility in Cold Spring, NY, was located near Foundry Cove. The plant was constructed in 1952 by the U.S. Army Corps. From 1952 through 1979 this facility manufactured nickel-cadmium (Ni-Cd) batteries, initially for military contracts.

Fig. 2. Foundry Cove, foreground, with Constitution Marsh Audubon Sanctuary at Center Left. South Cove is at the Rear

The battery manufacturing process requires the use of concentrated metal nitrate solutions that result in dilute waste solutions and metal precipitates. Both nickel and cadmium were used in large quantities; for a brief time, cobalt was used as an additive. The plant effluent was a fine suspension of nickel and cadmium hydroxides, in a pH range of 12 - 14, at a volumetric flow rate averaging 50 - 100 gallons/minute. The effluent usually contained from 10 - 100's ml/l suspended Ni and Cd hydroxides, depending upon production values. The total waste water output ranged from 100,000 - 200,000 gallons/day (Klerks 1987).

Of this amount, 51,004 kg of particulate Cd, and 1,569 kg of soluble cadmium were discharged directly into East Foundry cove; the remainder was discharged in the Hudson River (Klerks 1987). This earned Foundry Cove the dubious distinction of being "the most cadmium polluted site in the world".

In 1971, state officials detected high cadmium levels in East Foundry Cove in violation of the Clean Water Act of 1970. A civil law suit filed against Marathon Battery Company resulted in the dredging of all sediment exceeding 900 mg/g Cd based on wet weight. In 1972 - 1973, this dredging removed 10% of Cd released into Foundry Cove. These contaminated sediments (90,000 m3) were buried in a clay-lined, underground vault on the plant property.

Fig. 3. Distribution of cadmium in surface sediments in East Foundry Cove in 1974

In 1975, about 30% of the cove still had surface Cd levels in excess of 1000 ppm. In 1979, the Marathon company closed the plant and relocated. Merchandise Dynamics purchased the plant in 1980 for use as a book storage facility. In that same year Congress enacted the comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) to address the cleanup of the nation's hazardous waste sites.

Fig. 4. Distribution of cadmium in surface sediments in East Foundry Cove in 1983

Unlike some toxic compounds, e. g Unlike some toxic compounds, e.g., PCB's, which can be broken down by natural processes or through remediation techniques, metals like cadmium cannot be degraded. The natural reduction of surface Cd concentrations in Foundry Cove from 1971 to 1983 (prior to EPA's excavation and dredging activities) must be due either to: (1) deposition of new sediment, (2) transport of metals out of the cove, (3) redistribution of sediments within the cove, or (4) some combination of these processes. Depth profiles were established in order to determine if burial had occurred.

The benthic oligochaete, Limnodrilus hoffmeisteri (Fig The benthic oligochaete, Limnodrilus hoffmeisteri (Fig. 8), inhabiting cadmium-, nickel-, and cobalt-polluted Foundry Cove has evolved resistance to these metals (Klerks & Levinton 1989a,b). In survival experiments in which oligochaetes from Foundry Cove and South Cove (control site) were exposed to sediment with highly elevated metal levels, Foundry Cove worms survived the 28 day exposure while control worms did not. Second generation offspring of Foundry Cove worms reared in clean sediment also possess metal resistance.

An increased resistance to a metal can be achieved by a reduced accumulation of the pollutant. Reduced uptake rates have been reported for a number of different organisms, e.g., bacteria, algae, annelids, and fish (references cited in Klerks & Bartholomew 1991). But several studies comparing metal accumulation in populations differing in resistance did not find reduced uptake rates in resistant populations; some authors even found increased uptake rates.

If resistant individuals have increased metal uptake rates, then they must possess some physiological mechanism for metal detoxification. The ultimate research goal is to determine the mechanism(s) by which resistance has evolved in Limnodrilus hoffmeisteri inhabiting Foundry Cove.

Cumulative toxic materials, tend to increase in concentration, and are often associated with a specific tissue, e.g., Cd 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 toxic materials 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.

Due to the severity and extent of cadmium contamination, the EPA added Foundry Cove to the Superfund program, a national priorities list of abandoned hazardous waste sites requiring long-term cleanup.

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 landscaping 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.

Fig. 14. Aerial photograph of the site during restoration Fig. 14. Aerial 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.

Fig. 13. Towers Where Foundry Cove Sediment was Dewatered and Processed for Shipment

Fig 15. Railcars used to transport sediment from Foundry Cove (Cove is in foreground)

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 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.