The impacts of weathering on concentration and bioaccessibility of organic pollutants associated with plastic pellets (nurdles) in coastal environments

Nurdles, the pre-production plastic pellets, are a major source of plastic pollution in marine environments due to unregulated spills during production and transportation. We analyzed the types of plastics and associated organic pollutants on nurdles collected along the shoreline of Gulf of Mexico in Texas. Our results showed that the nurdles were made from polyethylene (81.9%) and polypropylene (18.1%). Polycyclic aromatic hydrocarbons (PAHs, 16 US EPA priority) and polychlorinated biphenyls (PCBs, 7 commercial congeners) sorbed to the nurdles were in concentration ranges of 1.6-14,700 ng/ g and 0-642 ng/ g, respectively. Heavily weathered nurdles tended to have higher concentrations of PAHs and PCBs than lightly weathered ones. The bioaccessibility of sorbed contaminants was evaluated using a simulated intestinal fluid. The results showed that the associated PAHs were more bioaccessible in lightly weathered nurdles (13.1 +/- 2.3%) than heavily weathered one (5.3 +/- 0.1%), and that no PCBs were bioaccessible. These findings are informative for toxicity evaluation and resource management of plastic debris in coastal environments.

Automated summary

Nurdles, pre-production plastic pellets, are a significant source of plastic pollution in marine environments, primarily made of polyethylene and polypropylene with sorbed polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Heavily weathered nurdles tend to have higher concentrations of organic pollutants, and the bioaccessibility of PAHs is higher in lightly weathered nurdles compared to heavily weathered ones. This study provides valuable insights for toxicity assessment and resource management of plastic debris in coastal environments.