Authorities will test samples taken from the Ramapo River to ensure that no significant amount of contaminants exist in the lower part of the Ramapo River past Pompton Lake Dam.
The Environmental Protection Agency (EPA) ordered the testing after it found “very very low concentrations of lead” in sediment taken from the bottom of the lake, said Phillip Flax, chief of the EPA’s correction action and special projects section.
The EPA has ordered DuPont to remove 100,000 cubic yards of sediment from part of the lake where mercury, lead, and copper seeped into for years from the company’s former explosives factory. The eastern part of the lake borders Wayne.
A 2011 study of sediment from the lake found contaminated sediment in downstream parts of the lake in Wayne below the dam.
“The values that came up for mercury for exceedingly low when compared to the standard,” Flax said. “Part of our responsibility is to ensure that mercury has not accumulated in areas where it could pose difficulty.”
A third-party testing company will take the samples to a state-certified laboratory where they will be tested. Samples will be taken from the lake and up to three miles downstream to Riverside Park in Wayne.
The floodgates on the dam could play a role in having potentially contaminated sediment migrate and settle downstream.
The gates are located on the bottom of the dam. Due to pressure, when they open, water and sediment from the bottom of the lake drains out first.
“I don’t want to characterize it as a concern, there’s always that potential, but that’s the reason we want to take a look,” Flax said.
EPA issued DuPont a final work permit earlier this month. The plan can be appealed until Feb. 4. If it is not appealed, DuPont has until March 6 to submit a work plan to the EPA. That plan will indicate where exact they intend to get the sample from.
“If we deem that sampling to be sufficient we will approve the plan. If not, we will go back to them and tell them what we expect in terms of sample location and sample density,” Flax said. “We intend to get it done sooner rather than later.”
Clean up is expected to begin in 2014, Pompton Lakes Mayor Katie Cole said at a special community meeting Tuesday, NorthJersey.com reported. DuPont still needs to obtain 11 state and local permits, the website said.