Microplastics in a freshwater environment receiving treated wastewater effluent

Small plastic fragments (microplastics or solid particles <5 mm in size or "microbeads" used in personal care products and cosmetics) may ultimately find their way into aquatic environments. We studied the presence of microplastics (particle sizes 53-105 μm and 106-179 μm) spatially and temporally in 3 connected urban lakes being fed by treated wastewater effluent in Lubbock, Texas. These lakes also serve as drainage during storm events. Water samples from drainage playa wetlands within the city were also collected. Our interest was in determining the presence or absence of microplastics in a freshwater environment as well as the source apportionment between personal care products (via wastewater) and discarded plastics (via runoff). Results showed that average concentrations of microplastics in samples collected from lakes ranged from 0.79 ± 0.88 mg/L to 1.56 ± 1.64 mg/L for the 53-105 μm size fraction and from 0.31 ± 0.72 mg/L to 1.25 ± 1.98 mg/L for the 106-179 μm size fraction. For samples collected from playa wetlands, average microplastic concentrations ranged from 0.64 ± 0.92 mg/L to 5.51 ± 9.09 mg/L for the 53-105 μm size fraction and from nondetectable (ND) to 1.79 ± 3.04 mg/L for the 106-179 μm size fraction. Our results (based on comparison of microplastic masses) suggest that urban runoff also contributes microplastics to surface water in addition to the treated wastewater effluent (in this particular case). The present findings may assist in adopting additional monitoring efforts and provide information on the potential contribution of secondary microplastic input into aquatic environments. Integr Environ Assess Manag 2017;13:528-532. © 2017 SETAC.