Measuring the Effect of Dietary Microplastic on Biomagnification Potential of Environmental Contaminants and Plastic Additives

Orally ingested microplastics (MPs) have been theorized to increase, decrease, and/or negligibly affect the uptake of hydrophobic organic contaminants (HOCs) and plastic additives in the gastrointestinal tract. Concentrations of selected polychlorinated biphenyls (PCBs) and two additives (UV-328 and octabenzone) in weathered polyvinyl chloride MPs and polar bear diet and feces were determined using modified total extraction methods. Analyte fugacities were investigated by equilibrating dietary or fecal mixtures, with and without added MP, within silicone polymer-coated vessels. High MP concentrations slightly decreased fugacities of PCBs and significantly increased those of the additives. Overall, results suggest MPs are not a major source of dietary HOCs, possibly exerting a cleansing effect instead, but potentially sources of plastic additives in a “Trojan Horse” effect. The presence of MPs had no major impact on fugacity-based biomagnification factors (BMFF) or thermodynamic biomagnification limits (BMFlim).