Microplastics, recognized as an important worldwide marine pollutant, are considered an emerging concern in freshwater ecosystems such as the Laurentian Great Lakes. Organisms at many trophic levels mistake microplastics for a food source. In addition to physiological effects, plastics act as a source-sink for many persistent, bioaccumulative compounds.
In collaboration with the Rochman lab at the University of Toronto and the Ontario Ministry of the Environment, we are determining the effects of microplastic consumption on fish species. We are doing this by testing the effect of rearing fish in the presence of pristine and environmentally contaminated plastic gathered from Lake Ontario under two concentrations, reflecting both current and predicted future aquatic conditions.
Our experiment uses fathead minnows (Pimephales promelas), native to the Great Lakes, as a model organism to quantify the molecular effects of microplastics during different life stages. We are asking the following questions:
1) What are the molecular effects (gene expression and methylation patterns) of microplastic consumption?
2) Does the magnitude of the effect of microplastic consumption vary with concentration and/or individual life stage?
3) Are there transgenerational effects of microplastic consumption on gene expression and methylation patterns?
4) How much of the observed effect is due to the exposure to the pristine microplastic versus the presence of sorbed chemicals?
This study will provide groundbreaking information on the persistent impacts of microplastic pollution, including the ability of microplastics to act as a vector for contaminants that could impact fish populations even after microplastic cleanup. The results of this study will increase our understanding of the molecular response of species to anthropogenic pollution with the goal of informing environmental policy decisions regarding marine microplastic pollution.