Keenan Munno, then a graduate student at the University of Toronto (U of T) said: "In 2015 we knew a lot less about microplastics and contamination in fish. I was expecting to see no particles in most fish."
This amount of plastic found in fish is a cause for concern. Besides the bullhead pulled from Lake Ontario, other fish were found to have harmful particles in their bodies as well.
In the Humber River, even minnows, which rarely get up to eight inches long, have as much as 68 particles. Of the human-made particles found in these marine animals, 59 percent were plastics in Lake Ontario, 54 percent in Humber River and 35 percent in Lake Superior. (Related: Polluted bodies: Researchers find shocking levels of microplastics in CHILDREN.)
In a 2013 study, researchers found an average of 43,000 microplastic particles per square kilometer of the Great Lakes surface water. Near major cities, they measured concentrations of as much as 466,000 microplastics per square kilometer.
Recent research also estimated that Great Lakes algae could be tangled with over one trillion microplastics. "Globally, 19-21 million tonnes of plastic waste were estimated to enter aquatic ecosystems in 2016," the study's authors wrote. The number is expected to double by 2030.
Chelsea Rochman, a co-author on the study and a U of T professor of ecology and evolutionary biology said, "I've been studying microplastics for a long time and this is the study that blew me away."
She began her microplastics research in trash gyres in the ocean, where she usually finds microplastics in one out of 11 fish, and only a couple pieces in a single fish. While the findings were concerning, it led people to believe that threat to animals was well into the future.
"We're finding that there are concentrations of microplastic in certain areas in the environment where the concentrations are so high that the animals might be at risk today," she said.
Unpublished research from Rochman's lab by a colleague of Munno's showed that microplastics can travel from the fish's digestive tract to the fillets, which could be one way they get to humans. Research has not drawn up enough links between microplastics and specific health issues in humans; however, they have been connected with neurotoxicity, metabolism and immunity disruption and cancer.
Even if these microplastics are not eaten by people, fish used as fertilizer or pet food can still spread microplastics far from aquatic ecosystems. Rochman worked to mitigate pollution in Lake Ontario with the U of T Trash Team and its partners, which installed filters on washing machines to capture plastic microfibers, and sea bins, which capture microplastics in the lake.
"In one sea bin sample—a 24-hour sample, one bin—we find hundreds of microplastics," Rochman said. The laundry filters likely capture one million in a month.
There is also growing concern over what microplastics can do to our health.
Frank Kelly, a professor of public health at Imperial College, London has grown increasingly concerned about the threat of microplastics in the last five years.
"One of the things which worries us is that plastic tends to be very hard to break down. In the outdoor environment, it takes decades to fully degrade. So microplastics may accumulate in the body, which probably isn’t good, but we haven’t got any hard evidence at this point that says they’re having an impact on human health. This is what we need to find out," he said.
The first concrete evidence that showed microplastics are lingering in the body was obtained earlier this year by obstetricians at San Giovanni Calibita Fatebenefratelli Hospital in Rome. They discovered microplastics in different shapes and sizes in placenta samples. Because of this, Kelly's research group is also now examining lung and intestinal samples from autopsies to see if microplastics can be identified in these tissues as well.
For scientists, this represents the first step towards convincing policymakers that microplastics are a serious health problem that need to be addressed.
Read more about the dangers of microplastics and other types of environmental pollutants at Pollution.news.