A new study out of Dalhousie University has found microplastics in the meat of lobsters caught off the coast of Nova Scotia.
The researchers from Dalhousie’s School for Resource and Environmental Studies collected 16 lobsters from four different areas of the province in 2022.
They then tested the edible portions of the tails using a special dye that makes microplastics glow when placed under a microscope.
Each of the 16 lobsters that were analyzed was found to contain various forms of microplastics, averaging six to seven microplastic particles per gram of meat.
Amber LeBlanc is the lead author of the study, which was published in the journal Regional Studies in Marine Science last week.
“I wasn’t too surprised to learn that there were microplastics present,” said LeBlanc, who was a master’s student at Dal at the time the study was conducted.
“I think the size of them, though, was very surprising.… Like, they’re so, so small. And then just the fact that they seem to potentially be coming from so many different sources.”
The average size of the plastics was 3.65 micrometres — about 30 times smaller than the diameter of a human hair.
The researchers were able to analyze the particles to determine what types of plastic were present, and found that the majority were polyethylene vinyl acetate, commonly found in packaging, laundry detergent pods, coating and sealants, as well as in parts for vehicles and boats; polyester potentially from clothing fibres; and polysulfone, an industrial-grade plastic that has many applications, including resins painted on ships to prevent organisms from attaching to them.
The lobsters were obtained from four sites that encompass lobster fishing area (LFA) 34 in the lower Bay of Fundy, LFA 33 on the South Shore, LFA 30-32 on the Eastern Shore and part of Cape Breton, and LFA 26A along the Northumberland Shore between Nova Scotia and Prince Edward Island.
While the microplastics were found in all samples, the lobsters collected from southwest Nova Scotia in LFA 34 had the highest concentration.
LeBlanc cautions, however, that given the small sample size of 16 lobsters, more research is needed to learn whether the geographic differences are a trend.
Tony Walker, one of the paper’s co-authors and a professor at Dal’s School for Resource and Environmental Studies, characterized the concentration of microplastics in the lobster meat as “relatively low” compared with those found in other types of food.
Health implications unknown
Karl Jobst is an associate professor in the chemistry department at Memorial University, and studies the impact of microplastics on human health — especially early in life.
His research group has found that microplastics are present in blood and placental tissue but he says there is still uncertainty about whether the exposures are high enough to cause adverse effects.
Jobst and his team have also conducted mouse model experiments using elevated concentrations of microplastics and found that they can cause adverse effects during pregnancy in mice, including fetal growth restriction, altered metabolism and abnormal brain development.
Jobst said he, too, is unsurprised by the finding of microplastics in lobster meat.
“Microplastics are widespread,” he said. “There are a growing number of studies in the literature reporting on the occurrence of microplastics in humans and wildlife on the highest mountains, in the ocean.”
The lobster study’s results are important, Jobst said, but it’s too early to draw conclusions about the impact on human health.
“I’m not sure I’d be ready to conclude that consuming lobster would represent a significant source of exposure,” he said.
Seafood industry responds
Representatives of Nova Scotia’s seafood industry raised questions about the lobster study, noting that the sample size is small and that microplastics have been found in many different foods, including both ocean-based and land-based proteins.
Stewart Lamont, the managing director of Tangier Lobster Company, which exports lobsters to clients in 13 countries, said he would like to see a comparative analysis of microplastic concentrations in different foods.
“Microplastics are common throughout the entire food chain. So I’m fairly confident this is not exclusively a lobster issue. I suspect it’s a food issue, a societal issue that we need to address on a national basis.”
Lamont said he’s not overly concerned that the study could impact consumption of lobster, as it’s generally a “celebration food” eaten a few times a year, rather than something that graces the plate several times a week.
Kris Vascotto is the executive director of the Nova Scotia Seafood Alliance, which represents lobster buyers, exporters and processors.
He said given the ubiquity of microplastics in food, lobster should be viewed in that larger context.
“I think it’s very important for consumers to realize that it is still an excellent protein,” he said. “It’s sustainably sourced … and there’s a lot of health benefits to continue consuming fish and seafood.”
Walker, one of the study’s authors, said the research was intended primarily to confirm whether microplastics were present in the edible meat of lobsters and what types of plastic were there.
He said previous research had only looked at microplastics in lobsters’ digestive tracts.
Walker and LeBlanc say more research is needed to understand the effects of microplastics on the crustaceans and on humans.
