AUGUSTA — The Department of Marine Resources in June closed an additional 5.5 square miles at the mouth of the Penobscot River to lobster and crab fishing because of high levels of mercury.
In February 2014, DMR closed about seven square miles at the mouth of the river in an area north of a line between Fort Point on Cape Jellison in Stockton Springs and Wilson Point in Castine along both sides of Verona Island. Late in June, the department pushed the southern boundary of closed area farther into Penobscot Bay to a line extending between Rocky Point (shown as Squaw Point on nautical charts) in Stockton Springs to Perkins Point. The expanded closure went into effect on June 21.
DMR spokesman Jeff Nichols said the lobster industry supported the expansion.
“The response has been positive,” Nichols said in a Tuesday email. “We’ve heard from both MLA (Maine Lobstermen’s Association) and DELA (Downeast Lobstermen’s Association) that they understood the need to make this change and appreciated our efforts to explain the closure in a way that acknowledges the impact on industry while protects consumer confidence in Maine lobster.”
In a statement announcing the expansion, DMR said it was acting in response to data gathered during a 2014 sampling program designed by the department, the Maine Department of Environmental Protection and the Maine Center for Disease Control and Prevention. A report of an analysis of that data was released in May.
The sampling program was implemented “to confirm the results of the 2013 Penobscot River Mercury Study” ordered by U.S. District Court Judge John Woodcock Jr. in connection with the federal lawsuit filed by the Maine People’s Alliance and the Natural Resources Defense Council against the Holtrachem Manufacturing Co. and its purchaser, Mallinckrodt, LLC. That study showed “elevated levels of methyl mercury in lobster tissue,” according to the MCDC report.
Last September, the court ordered Mallinckrodt to pay the cost of developing a plan to clean the riverbed of the Penobscot River of mercury pollution from the former HoltraChem site in Orrington. Late last year, the company hired the Chicago-based engineering firm Amec Foster Wheeler Environment & Infrastructure Inc. to design a cleanup plan and to make quarterly reports on its progress to a special master appointed by the court.
The next report is due in September and the planning process is nearing a conclusion. While no final plan is in place, the ultimate cost for cleaning up the river has been estimated to be at least $130 million.
To confirm the methodology and results in the court-ordered study, and to determine whether or not to change the closure boundaries, in 2014 and 2015 DMR conducted monitoring of lobster and crab in the closed area and beyond. According to the department, the 2015 results are not yet available.
Data from DMR monitoring work done in 2014 are from areas inside the original closure, including Odom Ledge, South Verona and Fort Point, and three areas outside the closure, including Cape Jellison, Turner Point, and Sears Island. All areas except Cape Jellison had been previously sampled.
Results from the court-ordered survey and 2014 DMR sampling were similar in that mercury concentrations in lobster tail and claw tissue decreased geographically from north to south.
According to DMR, mercury levels in lobsters sampled from the Cape Jellison shore, an area immediately adjacent to the closure, and the shore adjacent to Turner Point, were lower than most of the other areas sampled in 2014, but still elevated enough to warrant including in the closure.
According to data from the 2014 sampling program, on average, tails in 40 legal size lobsters harvested for testing along the south eastern shore of Cape Jellison contained 292.7 nanograms (a billionth of a gram) of mercury per gram of tissue (ng/g) while claws contained much less — 139.2 ng/g. According to the U.S. Food and Drug Administration, canned white tuna contains 350 ng/g of mercury.
The fisheries closures reflect an apparent abundance of caution.
According to scientists familiar with mercury pollution and the Penobscot River study, mercury is found in virtually all sea life. It is only a particular form or “species” of mercury — the methyl mercury referred to in the 2013 report — that is toxic and dangerous to human health. Generally, the highest concentrations of methyl mercury are found in fish such as tuna that literally are at the top of the food chain and feed mostly near the sea surface.
Lobsters and crabs collected during the 2014 sampling program were sent to an independent laboratory in Massachusetts for tissue analysis. According to the report released in May, “(t)otal mercury levels were measured” using a particular Environmental Protection Agency-approved method. “Results for total mercury” were returned to the Maine DEP.
The report does not indicate what fraction of the total mercury found was toxic methyl mercury. There is an EPA method of analysis to measure methyl mercury, but that test is much more expensive and complicated than the total mercury analysis.
In some analyses, all mercury that is measured is assumed to be methyl mercury. This would be an extremely conservative approach in terms of human health concerns, but would not accurately reflect any true level of risk of mercury toxicity.
The May report does not state whether the testing laboratory or the Maine CDE took that approach.
In addition to lobsters, DMR also included crabs in its original closure order and evaluated them in the ongoing monitoring work.
“Despite insufficient data on crabs in the PRMS study, we wanted to include them in the initial closure as a precaution,” DMR Commissioner Patrick Keliher said last month. “While the 2014 study does not show levels of concern for crabs, the closure will continue to include crabs because of enforcement challenges and to provide time to continue to analyze the data.”