Rivers and Wastewater-Treatment Plants as Microplastic Pathways to Eastern Mediterranean Waters: First Records for the Aegean Sea, Greece

Christina Zeri,Elias Dimitriou,Argyro Adamopoulou,Nicholas Koutsikos,Angeliki Koi,Efthymios Lytras

doi:10.3390/su13105328

Christina Zeri, Elias Dimitriou + Show 4 more

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https://doi.org/10.3390/su13105328

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Abstract

The present work provides the first records on microplastic (MP) amounts and types in rivers and wastewater effluents entering the Aegean Sea, eastern Mediterranean. Two rivers were sampled using a manta net (mesh size, 0.33 mm): a small urban and a medium-sized river with a rural, semiurban catchment. MPs in wastewater samples were collected at two wastewater treatment plants (WWTPs) within the Athens metropolitan area after secondary treatment and from a pilot biological membrane unit (MBR), using a series of sieves. MPs in the samples were identified using stereoscopic image analysis and spectroscopic techniques. MP concentrations in the rivers were found to be variable, with as high as 27.73 items m−3 in the urban river. Differences in MP shape types, sizes, and polymer types reflect catchment size and usage. MP concentration in wastewater effluents was found to be 100 times higher in the secondary treatment (213 items m−3) than that in the pilot MBR (2.29 items m−3), with filaments and polymers indicative of synthetic textiles and household use. Further research is needed in order to accurately determine variability in MP concentrations and fluxes from these two pathways in the eastern Mediterranean Sea and elucidate the role of rivers in MP retention.

Highlights

Plastics are manufactured petroleum-based polymers used in all kinds of consumer products, from single-use items and packaging to automobile parts
Plastic pollution is widely recognized as a global problem of ecological significance
Microplastics in Rivers In Kifissos River, the total number of counted MPs during high-flow conditions was 2171 particles; during low flow, it was 321 particles

Summary

Introduction

Plastics are manufactured petroleum-based polymers used in all kinds of consumer products, from single-use items and packaging to automobile parts. Their extensive use during the last few decades has led to an exponential increase in the generation of plastic waste, and the subsequent mismanagement and dispersion of plastics in the environment. The environmental concerns of this kind of pollution lie mostly on the chemical persistence of plastics and their fragmentation to small particles (

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