Nordic Aquafarms is hoping a new analysis of Penobscot Bay mud will lay to rest concerns about dredging for a pipeline to serve the land-based salmon farm the company hopes to build in Belfast.

The tests, conducted by Aqua Survey, Inc. of Flemington, New Jersey, using a plan written by the U.S. Army Corps of Engineers, found lower levels of mercury than earlier tests by Nordic, which had been disputed by opponents of the project on grounds that they weren’t from the actual pipeline route. While the new tests appear to check many of the boxes for independent oversight and affirm Nordic’s original tests, company representatives doubt that will sway the people who demanded the additional testing, a group they believe will remain against the salmon farm no matter what.

The testing has been required by the U.S. Army Corps of Engineers to satisfy a section of the federal Clean Water Act relating to potential impacts to the water column and benthic community.

Nordic’s plan calls for dredging roughly 36,000 cubic yards of material from the bay floor, both above and below the low-tide mark, to bury a cluster of three pipes that would carry saltwater to the recirculating tanks at the salmon farm and discharge treated wastewater from the facility back into the bay.

Penobscot Bay is known to have elevated levels of mercury originating from the HoltraChem chlor-alkali manufacturing plant in Orrington in the 1960s and ’70s. The area of Penobscot Bay near the Little River Estuary where Nordic plans to construct the pipeline lies more than 20 miles south of the source of the pollution, but samples taken to the north of the proposed dredge site showed mercury levels in the upper levels of sediment that were more than six times higher than background concentrations for estuaries along the central Maine coast, according to Dianne Kopec, the staff biologist for the study.

Maine Department of Marine Resources uses 0.5 parts per million as a guideline when determining whether an area should be closed to lobstering and fishing, as a portion of the Penobscot River estuary was permanently in 2014. Nordic Aquafarms tested in 2018 and found a peak level of 0.265 ppm in the vicinity of the pipeline. Those tests were disputed by opponents because the route of the pipeline was later moved, and the core samples were mixed before they were tested, potentially masking the higher concentrations of mercury in the upper layers.

The new samples were taken from 11 locations along the pipe route to a minimum depth of three feet. Each sample was divided into surface, transitional and deep layers for analysis. The results predictably showed higher levels near the surface, but the highest of them, 0.245 parts per million, was lower than Nordic found in 2018. And many of the samples had significantly lower concentrations.

“I would say it’s vindicating, but, you know, we haven’t really done anything,” Marianne Naess, commercial director for Nordic Aquafarms, said at a meeting with The Free Press September 8. “It’s been proven that what we’ve said all along is the truth.”

Ed Cotter, Nordic’s senior vice president of projects, added, “It’s accurate and it’s the whole story.”

The dredging would move 36,000 cubic yards of sediment from the bay floor to bury about half of the pipeline as it crosses the wide mudflats and continues underground beyond the low-water line. Nordic has proposed to do the work at low tide when possible and to install fabric turbidity curtains around the area to contain any sediment stirred up by the dredging. The material would be collected on barges during construction. Some of it would be returned to the bay floor to cover the pipeline, which will be buried for a length of 2,700 feet in the intertidal and subtidal zones, then partially buried for another 400 feet before emerging to be suspended above the bay floor. The remaining material would be towed on barges to Mack Point Cargo Terminal in Searsport and trucked to an upland disposal site. Opponents have questioned regulators with little success about what would happen to the potentially toxic water from the sediment, which would need to be drained before the material could be moved by truck.

On September 8, Naess said the dewatering will happen while the barges are inside the work area along the pipeline route. Cotter said sawdust or other material could be added after the dewatering to further solidify the material. He added that the sediment removed from the bay floor would be classified as clean enough to cap landfills containing more toxic soils.

The new sediment analysis data, which documented mercury, along with PCBs, pesticides and other contaminants, will be submitted to the U.S. Army Corps of Engineers to be measured against requirements of the federal Clean Water Act.

Maine Board of Environmental Protection is unlikely to consider the new data. The board approved a draft permit on September 4 and closed the required comment period on September 14.

The state and federal permits have been fiercely contested by opponents, who believe regulators have repeatedly needed to be prodded into doing basic diligence.

Responding to the new mercury data, Kim Ervin Tucker, attorney for Friends of Harriet L. Hartley, a conservation group opposing Nordic Aquafarms, and Maine Lobstering Union, said the mercury found in the new tests exceeds the levels found in meat of lobsters in the area that was closed by DMR in 2014.

Naess of Nordic Aquafarms said opponents have falsely equated the threshold for mercury in fish and shellfish meat with the higher threshold for mercury in sediment.