Influence of washing conditions and stain removal on microplastic release

Since the 1950s, plastics have become indispensable to human life but represent a huge environmental problem. In recent years, an increasing number of microplastics, MPs, have been found in indoor and outdoor air, in sediments, water and aquatic organism. People might not be aware that one of the main sources of sea and ocean plastic pollution comes from the washing machine wastewater, indeed after the MPs release of tyre abrasion, synthetic clothes are in second place. Synthetic fibers account for approximately 60% of the total global fiber production and fibres like polyester, acrylic and polyamide are the main one. During a wash, many parameters can influence microplastic release e.g. temperature, kind of detergent, duration of program, spin speed and washing process. In this study two kind of washing conditions, cotton cycle and delicate silk cycle, were tested on 100% polyester fabrics with known textile parameters. Moreover a comparison between the use of detergent alone vs detergent with a stain removal was carried out to establish the possible effects of this additive on microplastic release. The residues collected from filtration of water effluents through 40 ?m sieves were quantified by weight using micro-balance and characterized by optical, morphological and thermal analysis. The data were taken after 1st, 2nd, 3rd, 4th and 5th washing cycles for each polyester sample and four replicates were carried out to evaluate the reproducibility of the results. A comparison between the sums of the residues (mg/kg) of five washing cycles of each replicate was made. Delicate washing conditions decrease the release of microplastics by 12%, instead the addition of an additive does not influence the microplastic release.