Accelerated Weathering Increases the Release of Toxic Leachates from Microplastic Particles as Demonstrated through Altered Toxicity to the Green Algae Raphidocelis subcapitata.

Márta Simon,Nanna Hartmann,Jes Vollertsen

doi:10.3390/toxics9080185

Márta Simon, Nanna Hartmann + Show 1 more

Open Access

https://doi.org/10.3390/toxics9080185

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Journal: Toxics	Publication Date: Aug 5, 2021
Citations: 21	License type: CC BY 4.0

Affiliation: Aalborg University, Technical University of Denmark

Abstract

Studies that evaluate the impact of microplastic particles (MPs) often apply particles of pristine material. However, MPs are affected by various abiotic and biotic processes in the environment that possibly modify their physical and chemical characteristics, which might then result in their altered toxic effect. This study evaluated the consequence of weathering on the release of toxic leachates from microplastics. MPs derived from six marine antifouling paints, end-of-life tires, and unplasticised PVC were exposed to UV-C radiation to simulate weathering. Non-weathered and weathered MPs were leached in algae growth medium for 72 h to demonstrate additive release under freshwater conditions. The model organism, green algae Raphidocelis subcapitata, was exposed to the resulting leachates of both non-weathered and weathered MPs. The results of the growth inhibition tests showed that the leachates of weathered microparticles were more toxic than of the non-weathered material, which was reflected in their lower median effect concentration (EC50) values. Chemical analysis of the leachates revealed that the concentration of heavy metals was several times higher in the leachates of the weathered MPs compared to the non-weathered ones, which likely contributed to the increased toxicity. Our findings suggest including weathered microplastic particles in exposure studies due to their probably differing impact on biota from MPs of pristine materials.

Highlights

Microplastic pollution is perceived as a threat to the environment that potentially affects organisms at several trophic levels because of the particles’ small size [1]
The present study aimed to evaluate the impact of microparticle leachates derived from six commercial antifouling paints, end-of-life tires, and unplasticised PVC—materials which often contain a substantial fraction of heavy metals such as biocides, pigments, catalysts, and heat stabilisers [40,41,42]
The present study evaluated the toxic effect of microparticle leachates derived from various antifouling paint, end-of-life tire, and unplasticised PVC microparticles on a freshwater microalga species, R. subcapitata

Summary

Introduction

Microplastic pollution is perceived as a threat to the environment that potentially affects organisms at several trophic levels because of the particles’ small size [1]. MPs encompass plastic particles manufactured in the given size range, termed primary MPs, as well as secondary MPs, which are defined as plastic fragments formed from larger items or surfaces through chemical breakdown processes and physical abrasion [7,8]. MPs’ possible biological impact on a wide range of organisms has drawn scientific attention towards these pollutants. MPs can cause physical harm to organisms by blocking the gastro-intestinal tract or possibly introducing associated toxic compounds to the environment, or directly to the organism upon ingestion, through the leaching of potentially toxic substances [1,9,10]

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