Microplastic Release after Laundry of Synthetic Garments

Examensarbete för masterexamen
Infrastructure and environmental engineering (MPIEE), MSc
Plastic pollution is widely considered to an alarming problem due to the presence of plastics in water, soil and air. Microplastics are estimated to be the 3rd largest source of plastic pollution detected so far ending up in the marine environment. Microplastics can be a result of land based sources which can either come from care and cleansing products (e.g. toothpaste), breakdown products (e.g. fibers from synthetic textile, particles derived from car tyres) or deterioration of larger debris (e.g. plastic bags). Their main pathways are through stormwater, wastewater or direct release to sea. Their effects are largely unknown, although microplastics have been found in biota and in the human food web (e.g. in the salt, honey, etc). The amount of microplastics emitted from laundry remains very uncertain, with published emission rates ranging over several orders of magnitude. The aim of the thesis is to estimate the release of microplastics fibers from synthetic clothing after washing under specified conditions. A method to collect samples is developed and applied to the washing of different materials. The release is estimated in both relative fiber weight and particle numbers. Additionally, the effects of repeated washing and use of the clothes were investigated and related to their initial release. Finally, complementary results were obtained by microscopy analysis, including measurement of fiber size and characterization of textiles. The results show that the estimation of fiber emission from laundry is a challenging procedure. There is no standard method available and the quantification of emission rates in weight or particle number is affected by factors including the pore size of the filters, the presence of additives in textiles, the possible presence of environmental particles on the textiles and the large particle numbers. It is however clear from this study that microplastic fibers are released from laundry. Measured fiber emissions were found to be in the range of 97-2,3 mg per kg of textile or 0.8-2.6 million fibers per kg of textile (calculated taking into account the average number after use). Repeated washing caused a decrease in fiber emission. In contrast use of the textiles caused an increase in emissions. Microscopic observation of the textiles after washing and use clearly show deterioration of the materials that might explain the higher emission after use. This study supports that the emission of fibers from laundry significantly contributes to the environmental microplastic load, even if some of the emitted fibers are retained by wastewater treatment plants.
microplastics , synthetic textile , length distribution , diameter distribution , ESEM analysis , EDAX analysis , annual release
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