Wet wipes in untreated wastewater are a source of litter pollution to the arctic marine environment – a case study on the loads of litter and microplastics in wastewater effluents in Greenland†

Abstract

Plastic litter is ubiquitous in the Arctic marine environment, but knowledge of the importance of specific sources is limited. This project aimed to investigate the input of plastic from untreated sewage discharged to the sea in Greenland. A method was developed to sample and quantify inputs of plastic in different size fractions from wastewater from two towns in Greenland. Plastic findings were visually characterized in terms of abundance, morphology, size, and chemically by characterizing the polymer composition using FTIR spectroscopy. The wastewater was found to be a source of both macro- and micro-sized plastic pollution. Of the total litter load, 70% of the mass was from plastic items larger than 25 mm. Wet wipes were found to be dominating and constituted 59% of the total emitted plastic by mass, but other sanitary items (sanitary pads and condoms) were also detected. A polymeric characterization of the macro-items by ATR-FTIR revealed that the wet wipes were mainly of PET (polyethylene terephthalate, a polyester) but also viscose and cellulose wet wipes were detected. In the microplastic fraction (<300 μm), the main contributor was PP (polypropylene; 65%), but also PE (polyethylene), PES (polyester), PS (polystyrene), cellulose and other polymers were detected. A characterization of the microfibers revealed a large contribution of white/transparent fibers that primarily were composed of cellulose (67%) while a smaller fraction (10%) was polyester (PES), including polyethylene terephthalate (PET). The findings of white/transparent microplastic fibers in the wastewater suggest that a fraction of these fibers is directly related to the presence of the cellulose, viscose and PET wet wipes. Our results suggest that implementing either regulatory or behavioral measures to prevent wet wipes from entering the wastewater or using technical solutions to eliminate the discharge of wet wipes into the marine environment via wastewater, could significantly reduce the emission of plastics of all sizes from wastewater to the marine environment.