Continuous long-term monitoring of leaching from microplastics into ambient water - A multi-endpoint approach

Widespread pollution of aquatic environments by microplastics (MPs) is a serious environmental threat. Despite the knowledge of their occurrence and properties rapidly evolving, the potential leaching from MPs remains largely unexplored. In this study, 16 different types of MPs prepared from consumer products were kept in long-term contact with water, while the leachates were continuously analysed. Most of the MPs released significant amounts of dissolved organic carbon, up to approximately 65 mg per g MPs after 12 weeks of leaching, and some MPs also released dissolved inorganic carbon. Other elements identified in the leachates were Al, Ba, Ca, Fe, K, Mg, Mn, Na, Si, and Zn. Of those, Ca, K, and Na were detected most frequently, while Ca reached the highest amounts (up to almost 2.5 mg per g MPs). Additionally, 80 organic individuals were tentatively identified in the leachates, mostly esters, alcohols, and carboxylic acids. Some compounds considered harmful to human health and/or the environment were detected, e.g., bisphenol A or phthalate esters. The current results provide insight into the transfer of various compounds from MPs to ambient water, which might have consequences on the fluxes of carbon and metals, as well as of specific organic contaminants.