JEF DAUBER/Courier-Post

LORI GALLO/Courier-Post

The cruelest irony concerning the ecological rebound of the Delaware River is that while fish may be back in strong numbers, they are unsafe to eat.

It's now common to see anglers in places such as Burlington City, National Park and Gloucester City. That's because American shad, striped bass and weakfish have rebounded strongly with the cleanup of the river's most pressing pollution problem...sewage that used up dissolved oxygen fish need.

Yet officials must now grapple with historic toxins, including mercury and other heavy metals, chlorinated pesticides and PCBs--contaminants that can accumulate a million-fold in the fatty tissues of fish at the top of the aquatic food chain.

And scientists don't know when--or if--these toxins will no longer be a concern.

"It's not getting better, and, in some cases, it may be getting worse," said Thomas Fikslin, a scientist with the Delaware River Basin Commission.

A 1998 U.S. Public Interest Research Group study ranked the Delaware as one of the 9th most polluted rivers in the nation. More than 12 million pounds of toxic and cancer- causing chemicals were discharged into the river from 1992 to 1996, according to the study.

But that ranking is not fair, said Fikslin. The largest share of the industrial discharges was comprised of ammonia from industry and nitrate compounds from sewage treatment plants. These chemicals are nutrients that can result in lower dissolved oxygen levels. But for reasons not understood, they aren't creating problems, Fikslin said.

And current industrial discharges are not contributing to toxins found in fish, he said. Rather, the culprits include industrial pollution and spraying of pesticides containing the now-banned DDT.

But the most troublesome contaminant is PCBs, a class of chemicals once used extensively as an insulator in electrical equipment and in plasticizers manufactured along the river. PCBs are considered harmful at very small levels...and are mysteriously still getting into the river even though they are banned.

While DDT levels in fish seem to be declining with the bans, PCB levels in fish appear to be on the rise. This increase baffles researchers, who suspect PCBs may be still trickling into the river and its creeks through leaking landfills, improper storage and illegal dumping.

And PCBs have also been detected in municipal sewage discharges, suggesting PCBs are being illegally discharged into those systems.

The Basin Commission and state environmental agencies are currently establishing programs to try to track down these sources...but they say the task is daunting. In the meantime, environmentalists complain fish consumption advisories meant to protect the public from such contaminants are contradictory and confusing, varying between species and across state boundaries.

Currently, environmental officials in New Jersey, Delaware and Pennsylvania are trying to make consumption advisories more consistent...but the task has been wrought with problems. For example, Pennsylvania recently eased some of its advisories after adopting protocols that assume anglers are well-educated in safe ways to prepare fish. But New Jersey and Delaware regulators don't agree that preparation methods adequately reduce health risks.

A good rule of thumb, Fikslin said, is to consume no more than a half-pound of Delaware fish every five weeks.

"The problem is some subsistence fishermen eat much more than that," he said. "I think everyone recognizes the advisories could be coordinated and disseminated in a better fashion than they are."

Jerry Flanagan, of the New Jersey Public Interest Research Group, agrees many of the river's problems are part of its industrial legacy. However, he argues officials are missing current health-threatening industrial pollution problems through lack of aggressiveness.

NOTE: For example, it wasn't until recently the Basin Commission found two cancer-causing chemicals used by industry -- 1,2-dichloroethane (DCE) and tetrachloroethene (PCE) -- exceed water quality criteria in the river. DCE and PCE are being released by industrial and municipal wastewater treatment plants that treat industrial wastes.

"There hasn't been adequate analysis, so there are things in the river we don't even know about..." Flanagan said.

The chemicals have not been detected at the New Jersey-American Water Co. regional river water treatment plant in Delran. Company officials say its treatment system would be able to remove the chemicals.

Nevertheless, the chemicals concern the basin commission. Since last year, the commission has been considering tougher standards that could force municipal and regional sewage treatment operators to track down industries that are sending large volumes of these chemicals into their systems...then take actions to reduce them.
See also: Major Pollutants in the Delaware River