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The aim of the research is to determine the concentration and characterize microplastics found in clams’ tissue in local St. Lawrence rivers. Microplastics are small plastic pieces that are less than 5mm in size, and they are classified into 3 categories: pellets, fibers, and fragments. The increasing concentration of microplastics poses a global threat to aquatic ecosystems. Due to their small size, they can be ingested by several aquatic organisms. Research has linked the ingestion of microplastics to issues like reduced growth rate and reproductive complications which could potentially collapse an entire ecosystem. Additionally, they can bind to carcinogenic chemicals in the environment that could lower immune response in humans.
The first step of the procedure involves breaking down the clam tissues by boiling them with Fenton’s reagent, a solution of iron (II) sulfate (FeSO4) and 30% hydrogen peroxide (H2O2), to extract the microplastics from the tissue (Munno et al. 2018). The second step involves precipitating Fe3+ by adding 3M of NaOH and centrifuging to density separate the solid Fe(OH)3 from the liquid portion of the solution. The third step involves dyeing the digested samples Nile red, Evens blue/Calcofluor white.
Microplastic fragments and fibers were found in some of the tissue samples. The size of the clams was recorded to investigate the relationship between clam size and the number of microplastics present in each sample. Lastly, microplastics were found in samples taken from lakes that were not expected to have microplastics because they were not close to human settlements and were not subjected to plastic waste. An explanation for this finding is that microplastics are entering these lakes through atmospheric deposition, that is, tiny plastic pieces are being transported by wind and deposited into the lakes.