Meadow Marsh Cleanup Begins

August 2003

Meadow Marsh Cleanup Begins

Before the cleanup workers checked Meadow Marsh pond for Tiger Salamanders

Background

The Meadow Marsh, also known as the Upland Recharge/Meadow Marsh, was designated as Area of Concern (AOC) 8A. The Marsh was used from 1973 to 1978 to conduct experiments to evaluate the capacity of small natural and man-made terrestrial and aquatic ecosystems for treating sewage and recharging ground and surface waters. Liquid effluent from residential cesspools, and treated and untreated effluent from the BNL Sewage Treatment Plant was applied to various study areas within the Meadow Marsh. Prior to remediation, the area was a series of overgrown fields and man-made basins. This area was included in the Site-wide Biological Inventory conducted during 1994 and 1995 (LMS, 1995).

The Meadow Marsh contained six small man-made ponds underlain with a PVC liner containment system to prevent recharge to groundwater. The PVC liners in the three western ponds and the northeastern pond had deteriorated and no longer retained water. The two eastern ponds were of concern because they served as breeding ponds for the Eastern Tiger Salamander, a New York State endangered species. The sediment depth in the various ponds ranged from two inches to two feet and was contaminated with low-levels of pesticides, metals, and radionuclides.

A Preliminary Ecological Risk Screening was performed in 1996 and a Focused Ecological Risk Assessment and Addendum was completed in 1999. The Assessment concluded that there was a toxicity exposure risk, from various metals (copper, zinc, and aluminum) and trace amounts of americium-241 and cobalt-60 in the pond sediment, for larval salamanders living in the ponds.

Remedial Action

The remedial objectives for the Meadow Marsh were to prevent or minimize the uptake of contaminants present in the soils by ecological receptors. The cleanup, which began in August 2003, included pumping out nearly 55,000 gallons of water from the ponds and removing 240 cubic yards of contaminated sediment and degraded pond liners. The sediment was shipped by rail to a licensed disposal facility and the water was transported to an off-site disposal facility.

Prior to the start of the cleanup, workers combed the ponds using dip nets and a seine net. Five Tiger Salamanders were removed and placed in another pond on-site.

Following the sediment removal, the berm separating the two cleaned ponds was removed and one large pond was created. New soil, a new liner, and wetland plants helped establish the new pond. The project was completed in September 2003.

Documents / Links

OU I Record of Decision

Meadow Marsh Closeout Report