By LAWRENCE R. HAJNA
Courier-Post Staff
PHILADELPHIA -- A recent study shows sediment contamination in the Delaware River from toxics like PCBs and DDT to be more widespread than previously documented.
The study, hoped to be a stepping stone ultimately leading to a cleaner river and safe fish, measured sediment in side channels that had not previously been tested.
Until now, only the main shipping channel had been tested during routine depth maintenance projects.
The study, performed by the Arthur D. Little Co. of Cambridge, Mass., confirmed the most toxic river sediments are to be found from Trenton to Marcus Hook, Pa.
Among the toxics found are PCBs, DDT and its degraded constituents, mercury, and polynuclear aromatic hydrocarbons from oil and fuel spills. The study said that PCB contamination is more widespread than previously thought.
"This will help us find out where the contaminants are coming from," said David Pollison, planning head for the Delaware River Basin Commission, which participated in the study.
The study was commissioned by the Delaware Estuary Program, a federal effort coordinating local, state and regional planning for the Delaware River and Bay.
It should lead toward a better understanding of just how much of the sediment contamination has resulted from past industrial discharges and how much is still coming into the river's watershed, Pollison said.
If new, it's not likely that much is from current industrial discharges since many of the most persistent of the contaminants have been banned. Rainwater runoff is the more likely suspect.
For example, officials suspect cancer-causing PCBs and other hazardous chemicals continue to trickle into the river's watershed from Superfund and other chemical waste sites that have not been fully contained yet even though their manufacture was banned in 1976.
They also suspect that the biologically-persistent DDT, which causes eggshell thinning in threatened birds like osprey and eagles, is still being carried by rainwater runoff into the river's tributaries from farms and other areas. The pesticide was banned in 1972.
Once such chemicals get into waterways, they become an integral part of aquatic systems. Microorganisms eaten by larger fish eventually accumulate in fish used for sport and consumption.
Over the years, New Jersey, Pennsylvania and Delaware have issued various advisories against consuming numerous species of fish caught in the Delaware and many of its tributaries.
"Rather than come up with fish advisories, we'd rather not have fish advisories at all," said estuary program director Robert Tudor. "That's going to take a long time."
But he and Pollison said the new study is a step in that direction. Like environmental detectives, officials hope to locate "hot spots" off the main shipping channel that will lead them to sources of runoff pollution.
Once identified, these sources may be prioritized for cleanups or steps could be taken to block further runoff contamination, Tudor said.
