Fate of Plastic Debris and Associated Chemical Contaminants 

In our laboratory, one of our research objectives is to determine and quantify the sources and sinks of plastic debris in freshwater and marine habitats. Current and ongoing projects include measuring the sources and sinks of microplastic into urban watersheds across North America, examining plastic as a source of chemicals to aquatic habitats and quantifying plastic and associated chemical contaminants in wildlife (e.g., birds and fish), including fish and shellfish sold directly for human consumption.

Our past work examined the transfer of chemical contaminants, including organics (e.g., PCBs and PAHs) and metals to and from plastic debris. We found that for organic chemicals, polyethylene, polypropylene and polystyrene accumulate much greater concentrations of chemicals than PET and PVC. We have also shown that chemicals associated with plastic debris can transfer to fish in the laboratory and have found evidence in nature suggesting that plastics are a source of chemicals to fish. Lastly, we have shown that fish are a sink for plastic debris in nature, including our findings that 1 in 4 fish purchased from fish markets in Indonesia and the USA had anthropogenic debris, including plastic and microfibers, in their guts.

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Ecological and Toxicological Impacts to Wildlife

One of our main objectives is to understand how mixtures of aquatic contaminants impact the ecology of aquatic ecosystems (e.g., populations, communities). Current and ongoing projects include analyzing the weight of the scientific evidence regarding impacts of plastic debris to wildlife, measuring ecologically relevant impacts of microplastic debris in laboratory experiments under environmentally relevant exposure scenarios, and observational experiments in the field to help determine if impacts observed in the lab occur in nature.

Our previous work has identified gaps in the weight of evidence regarding impacts from marine debris in the literature through 2013. This work showed that while we know quite a bit about sublethal impacts to individual organisms, we know little about impacts to populations, communities and ecosystems. Some of this evidence was demonstrated via our own laboratory experiments where we tested and demonstrated impacts to individual fish from environmentally relevant concentrations of microplastic with and without a mixture of chemical contamination.

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Applying Science to Policy

I believe that scientific evidence should be part of the policy-making process and that scientists should be given a spot at the policy-making table. To do this, scientists must be able to communicate effectively and clearly to non-scientists. In addition to research, I teach science communication workshops. I also participate in outreach activities to share my work with schools and aquariums, have written policy briefs when relevant (e.g., microbeads in personal care products) and have participated as an expert witness for government hearings. It is important to me that our research bridges the gap between academic research and policy change. My collaborations with NGOs, such as Ocean Conservancy, and with governments help facilitate this process.

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