Studies of the Photo-transformation of Emerging Contaminants Adsorbed onto Plastic in an Aqueous Environment

The accumulation of plastic debris in the environment poses many threats to the environment and human health (1). One way these plastics can cause environmental damage is through the absorption and transfer of potentially toxic compounds to aquatic animals which in turn transfer these toxins to humans when consumed. These toxins are believed to alter basal metabolic rates and increase adipose tissue production in humans (2). Hydrophobic chemicals such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) all accumulate on microplastics. The focus of our studies is to understand how the surface area and type of plastic influence the extent of photodegradation of emerging contaminants in aqueous solution when irradiated at 300 nm at different times. Triclosan and 1-(4-hydroxyphenyl)nonane were selected as model pollutants for the irradiation studies because they are known to adsorb to plastic in aqueous environments (3). 1-(4-Hydroxyphenyl)nonane produces more decomposition products upon irradiation than triclosan, and therefore we reasoned that it might be a more sensitive probe of the effects of surface area and the polymer structure of the plastic than the triclosan.