The Fox River in Brown County is far more contaminated with possible cancer-causing chemicals than first estimated by regulators in 2003, officials said.
The 6.2 million cubic yards of sediment with polychlorinated biphenyl concentrations, or PCBs, are already enough to make it the largest known sediment cleanup ever attempted in North America.
But the paper companies involved are dealing with estimates closer to 7.5 million cubic yards that have been ordered to be cleaned up in two separate Record of Decisions filed for different parts of the river.
Testing in the last two years also show contamination levels reaching as much as 15 feet or more below the river's bottom.
State regulators, working with two of the paper companies on engineering plans, said the evidence now supports a greater role for capping in the cleanup.
"This is still a dredging project," said Greg Hill, chief of sediments management for the state Department of Natural Resources. "But dredging is not 100 percent effective."
The chemicals were released into the Fox River by seven area paper mills over a 17-year period ending in 1971. PCBs are implicated in a range of health problems - including child development, complications in pregnancies and birth defects. The Environmental Protection Agency lists PCBs as a probable human carcinogen, or cancer-causing agent.
Rebecca Katers, director of the Clean Water Council, said environmentalists feared modifications to the cleanup - like capping the river's bottom instead of dredging it - ever since the government's Record of Decision was released.
"We're concerned about a weakening of the cleanup during the amendment process," Katers said. "Our concern is that a large chunk of the contamination will be capped or incinerated. We think both technologies are risky."
There's a meeting in Green Bay on Thursday as experts with Shaw Environmental & Infrastructure, working for Georgia-Pacific Corp. and NCR Corp., present what they know of the pollution and how they plan to fix the problem.
There are limits to dredging, according to recent cleanup operations and studies, Hill said. Instead, caps of sand and gravel have proven themselves to be effective in some situations.
"We don't think this will speed the cleanup," Hill said. "But it will speed the recovery of the river."
The cleanup mandated in the first record is under way.
Dredging is in its first full year on Little Lake Butte des Morts. But no agreement has been reached on who will conduct the vastly larger cleanup downstream or how the paper companies will split the costs.
Al Toma, Georgia-Pacific's northern regional manager for governmental affairs, said that despite their best efforts to design an efficient cleanup, the cost to the paper companies will likely exceed the $300 million estimated by the government in 2003.
But the cleanup is in sight, he said, estimating it will take up to 10 years.
"We are so much closer to getting this thing done than ever before," he said.Associated Press via Duluth News Tribune
