Leaching and transformation of chemical additives from weathered plastic deployed in the marine environment

Plastic pollution causes detrimental environmental impacts, which are increasingly attributed to chemical additives. However, the behaviour of plastic additives in the marine environment is poorly understood. We used a marine deployment experiment to examine the impact of weathering on the extractables profile, analysed by liquid chromatography-mass spectrometry, of four plastics at two locations over nine months in Aotearoa/New Zealand. The concentration of additives in polyethylene and oxo-degradable polyethylene were strongly influenced by artificial weathering, with deployment location and time less influential. By comparison, polyamide 6 and polyethylene terephthalate were comparatively inert with minimal change in response to artificial weathering or deployment time. Non-target analysis revealed extensive differentiation between non-aged and aged polyethylene after deployment, concordant with the targeted analysis. These observations highlight the need to consider the impact of leaching and weathering on plastic composition when quantifying the potential impact and risk of plastic pollution within receiving environments.

Automated summary

Plastic pollution has significant environmental impacts, largely due to chemical additives. However, the behavior of plastic additives in marine environments is not well understood. A marine deployment experiment was conducted to investigate the effects of weathering on the extractables profile of four types of plastics in New Zealand over a period of nine months. The concentration of additives in polyethylene and oxo-degradable polyethylene was strongly influenced by artificial weathering, while polyamide 6 and polyethylene terephthalate showed minimal change. These findings emphasize the importance of considering leaching and weathering effects on plastic composition when assessing the potential impact and risk of plastic pollution in receiving environments.