Low density polyethylene sorption of polycyclic aromatic hydrocarbons in aquatic environments and the role of biofilm
Plastic pollution is a growing problem threatening ecosystems and human populations across the globe. One of the minimally studied impacts of this widespread material is its ability to sorb, transfer, and preserve harmful contaminants, including polycyclic aromatic hydrocarbons (PAHs). PAHs are carcinogenic, carbon-based pollutants formed by the incomplete combustion of carbon-based materials. In this exploratory field study, I first analyzed the differences in PAH sorption by plastics between wetland and stream sites. Secondly, I investigated the potential roles temperature, specific conductivity, total suspended solids, pH, and biofilms play in impacting PAH sorption to the highly sorptive plastic, low density polyethylene (LDPE). Results showed levels of PAHs sorbed to LDPE tended to be higher in stream sites than in wetland sites, although the differences were not always significant. This was likely due to external environmental factors at each individual site that impacted dissolved PAH concentrations in the water column. Additionally, results showed the most impactful factors studied included biofilm mass, specific conductivity, and temperature. In the field study, a significant decrease in biofilm at one particular replicate at a site, corresponded with a drastic increase in sorbed PAHs. This observation led to the development of a controlled laboratory study aimed to determine if this result was due to one of the following: the biofilm was creating an interference in the testing process, the biofilm breaks down PAHs; or the results were an anomaly. The laboratory study supported the notion that biofilm does play a role in breaking down PAHs, inhibiting PAH sorption by plastic. These studies highlight the importance wetlands and diverse microbial communities play in reducing PAH sorption by plastics; ultimately reducing PAH persistence in the environment and keeping these pollutants out of the food chain.
Polycyclic aromatic hydrocarbons, Low density polyethylene, Plastic, Aquatic pollution
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SUNY Brockport Department of Environmental Science and Ecology