Dr. Thamara Laredo Investigates Microplastics
A City of Orillia Partnership Could Provide Insights into Reducing Pollution
Dr. Thamara Laredo has developed practical solutions to deal with microplastics at a City of Orillia beach.

In partnership with the City of Orillia and the City's director of environmental services, Greg Preston, Dr. Laredo's research team conducted a survey of litter found at Couchiching Beach Park during the summer of 2026. This 14.5-acre park is next to downtown Orillia and hosts popular summer events, in addition to attracting swimmers, kayakers, paddleboarders, and picnickers.
Dr. Laredo (left), a Lakehead University chemistry professor, thought that findings of the litter survey had the potential to become the first step in reducing pollution. This prompted her to expand the project to include analyzing litter distribution and creating a geo-map of discarded waste for the city.
"Plastics break down into small fragments through environmental weathering," she explains. "Smaller fragments eventually become microplastics that enter the lake. That's why we were interested in studying the fragmentation patterns of plastics that break down into microplastics, particularly at the beach."
The Microplastics Challenge
Any piece of plastic smaller than 5 mm in any single dimension is classified as a microplastic. Dr. Laredo focused on microplastics that were six-tenths of a millimetre, which is about the size of a dust mite or a grain of sand.
Microplastics are pollutants that harm humans, animals, and ecosystems. Their small size makes them difficult to remove, making it easy for humans and animals to ingest them. Microplastics in water can turn into even smaller nanoplastics that cross the blood-brain barrier in animals and humans. "This is why we wanted to find mitigation strategies to deal with this challenge," she says.

Microplastics in lakes and rivers lead to a process called biomagnification. "Small fish confuse microplastics with food or eggs and eat them," Dr. Laredo says. "These small fish are eaten by larger fish, resulting in highly polluted animals with endocrine disruptions that are then eaten by humans. It's the same problem when birds and people eat fish. Biomagnification can cause the collapse of species and lower sperm counts." Right, student researchers at Couchiching Beach Park.
To carry out this research project, Dr. Laredo applied to Mitacs, a Canadian not-for-profit organization that connects academia, industry, government, and global partners to solve real-world problems. It does this by offering paid work-integrated learning (WIL) opportunities to domestic and international students and postdoctoral fellows.
Dr. Laredo was matched with two undergraduate students who had just completed the third year of their environmental degrees—Diana Figueroa who is studying Natural Sciences and Environmental Education at Universidad del Valle, in Cali, Colombia, and Salma Bouchnak who is studying environmental sciences in Tunisia.
The researchers assisted Dr. Laredo over the 12-week period of the research project beginning in May until the end of July 2026. They investigated plastic distribution across the beach and helped design the litter geo-map.

Above (left to right), Diana Figueroa, Juan Esteban Florez (a Mitacs student who worked on a different research project), Dr. Laredo, and Salma Bouchnak.
"I enjoyed seeing how what we observed in the field could gradually become something we could understand through the data," Diana Figueroa says.
"Diana and Salma were both amazing and very hard workers," Dr. Laredo says. "They were also excited to learn about Canadian culture and to network."
Time to Hit the Beach
Salma, Diana, and Dr. Laredo worked together surveying, sampling, and analyzing the microplastics they collected. Samples were collected at the same locations throughout the study. The team measured along the beach's wrack line (the place where the high tide deposits organic debris like seaweed) and collected samples every 10 feet.
The researchers found litter hotspots under shrubs and at the edge of the beach along the wrack line.

The researchers looked at sand samples to see if they contained microplastic and the extent of weathering. "We did infrared spectroscopy to determine if what we were looking at was plastic and not another material," Dr. Laredo says. Left, Diana Figueroa studies samples in Lakehead University's chemistry lab on the Orillia campus. Microplastics don't dissolve in water. Once they are in the water, they attract other pollutants to them, which increases their toxicity. After completing her research, Dr. Laredo proposed that the City of Orillia run an awareness campaign to educate the public about the dangers of cigarette butts, including putting up signs at Couchiching Beach Park.
Plastics constituted about 90% of all litter in the park. Cigarette butts, which have filters made of cellulose acetate, were the number-one source of plastic pollution. "Not many people realize that cigarette butts contribute to microplastic formation. People think they are made of cotton or paper and that they degrade easily," Dr. Laredo says. "Food packaging was the second highest source—including granola bar wrappers, chip bags, and juice boxes with little plastic straws. "The straw packaging often flies out of garbage cans."
Once plastic waste settled in hotspots, it began breaking down into smaller pieces of plastic. "The city grooms the beach regularly during the summer months," Dr. Laredo says. "The hotspots we found were in places where the city tractor couldn't reach. Although beach grooming does not remove any litter, it became an additional variable in calibrating the geo-map because it shifted the distribution of the plastics by burying them."
Right, Diana Figueroa takes measurements at Couchiching Beach Park. "Before coming to Lakehead, I had been involved in a community project with black families in my neighborhood in my hometown of Cali, Colombia, focused on transforming waste together," she says. "So, when I saw the opportunity to explore plastic pollution from a research perspective at Lakehead University, it immediately caught my attention. I found it particularly interesting to study plastic pollution in an urban freshwater environment. I had mostly encountered discussions about plastic pollution in marine environments, so this project gave me a different perspective on the problem and on the role that freshwater ecosystems can play."
The researchers also found that the amount of discarded plastics was much higher in the month of May compared to June, when park staff are hired to clean the park. "We recommended that park staff start cleaning up these hotspots earlier in the year to prevent the migration of the microplastics into the water," Dr. Laredo says.
"I've been collaborating with the City of Orillia for many years, and we have a great working relationship," she adds. "We are united in our efforts to keep our community healthy and our environment flourishing."

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