Estimating Microplastics related to Laundry Wash and Personal Care Products released to Wastewater in Major Estonian Cities: a comparison of calculated and measured microplastics.

Microplastics (MPs) research still at the budding stage in Estonia. A theoretical model build on substance flow analysis principles was developed. The goal of this study is to broaden understanding of MPs-types in wastewater and their contribution from known sources, quantify their presence based on model prediction and measurements. The authors estimate MPs from laundry wash (LW) and personal care products (PCPs)) in wastewater in Estonia. We found out that total estimated MPs load per capita from PCPs and LW in Estonia were between 4.25 - 12 tons/year, 3.52 - 11.24 tons / year respectively, and estimated load ended up in wastewater were between 700 - 30,000 kg/yr. and 2 - 1500 kg/yr. in WWTPs influent and effluent stream respectively. Finally. We conducted a comparison between estimated MPs load and on-site sample analysis and observed a medium-high level of MPs being discharged into the environment annually. During quantification and chemical characterization using µFTIR analysis, we found that microfibers with a length of 0.2-0.6 mm accounted for over 75% of the total MPs load in the effluent samples collected from four coastal WWTPs in Estonia. The estimation avails us broader overview about the theoretical MPs load in wastewater and gain valuable insight into developing process methods that prevent MPs accumulation in sewage sludge for safe application in agriculture.