The Effect of Microplastics on Terrestrial and Aquatic Organisms

The pollution of microplastics (MP) — plastics less than 5mm in size — has become a pressing environmental issue. Microplastics, often taking the form of microbeads used in commercial products, are ubiquitous in our ecosystems and are a serious threat to many organisms that ingest it. Our experiment was designed to determine the biological effect microplastics have on the health of aquatic and terrestrial organisms. We chose Daphnia magna , Brassica rapa, and Lumbricus terrestris as our model organisms and performed a separate microplastic experiment for each. For all three experiments, we prepared one stock solution of 100 mg/L of MP for the HCS (high concentration solution), one stock solution of 5 mg/L of MP for the LCS (low concentration solution), and one stock solution of 0 mg/L of MP for the control solution. After introducing microplastics to each organism for a period of time, we measured certain biological parameters like viability, growth rate, and reproductive success. We hypothesized that the HCS are more detrimental to the health of organisms than the low/no concentrations. While some trials demonstrated a strong correlation between MP concentration and the deteriorating health of the organism, other trials had a more vague relationship. The variation in results is likely attributed to the differences in experimental environments.