A few months after domoic acid was detected at harmful levels along Maine’s coast, the state has received a $32,000 grant to improve its ability to test for the presence of the toxin.
Phytoplankton species that generate the acid have been found in Maine marine water for years, but never to the extent that it appeared earlier this fall, according to the Maine Department of Marine Resources. The levels raised concerns that people might be exposed to amnesic shellfish poisoning by consuming tainted shellfish, which in turn prompted the state agency to shut down shellfish harvesting areas between Bar Harbor and the Canadian border from September to mid-November.
To lessen the potential impact of future similar closures, the Department of Marine Resources will use the grant funds from the Maine Outdoor Heritage Fund to acquire equipment and train its staff on how to test shellfish samples for domoic acid, the department indicated Friday in a prepared statement.
For the past two years, the Department of Marine Resources has been working with Bigelow Laboratory for Ocean Sciences in East Boothbay to test shellfish harvested from areas where the presence of domoic acid and other naturally-occurring toxins known as “red tide” are suspected of having contaminated wild-grown bivalve shellfish species such as mussels, clams, oysters, quahogs, snails and whelks.
In the case of domoic acid, the process begins when routine water sampling along the coast reveals the presence of the phytoplankton species Pseudo-nitzschia, which produces the toxin. Department of Marine Resources scientists and trained volunteers then conduct a secondary test to see if domoic acid is present in the water sample.
If the secondary results come back positive, shellfish samples are harvested in the vicinity and sent to Bigelow Lab, which uses a method known as high-pressure liquid chromatography to determine if the acid is in the shellfish. The shellfish beds where the samples were taken are closed if domoic acid levels of 20 parts per million or higher are found in the tested shellfish, according to the Department of Marine Resources.
Kohl Kanwit, director of the Department of Marine Resources’ public health bureau, said in the release that the availability of the chromatography testing at the East Boothbay laboratory enabled the department to greatly improve its biotoxin monitoring program. The acquisition of its own chromatography equipment is expected to improve the state testing program even further.
“We began working with Bigelow Lab in 2014 to implement [high-pressure liquid chromatography] testing for red tide,” Kanwit said. “As a result, Maine was the first state in the nation to transition from using mice to test for biotoxins to the more precise chromatography method, which uses chemical analysis instead of live animals.”
Before the chromatography testing method became available, the Department of Marine Resources only collected shellfish samples when health officials contacted them about a possible shellfish poisoning case. The samples were sent to the federal Food and Drug Administration for testing, the results of which could take up to 10 days to produce, according to department officials. While the state waited on results, the areas where the shellfish was harvested was closed as a precaution.
The results did not always come back positive, however.
In 2012, about 50,000 acres of shellfish harvesting areas were closed for nine days while FDA results were pending — only to be reopened when the results indicated there were “no levels of concern,” Department of Marine Resources officials indicated.
“[High-pressure liquid chromatography] testing by Bigelow Lab was a major improvement for us and the [the shellfish] industry,” said Department of Marine Resources biologist Bryan Lewis, who will oversee the project. “The new equipment, which will be housed at the [Department of Marine Resources] lab in Boothbay Harbor, will further strengthen our ability to deal with this emerging biotoxin.”