Exploring the impacts of microplastics and associated chemicals in the terrestrial environment – Exposure of soil invertebrates to tire particles

Salla Selonen, Andraž Dolar, Anita Jemec Kokalj, Lyndon N.A. Sackey, Tina Skalar, Virgínia Cruz Fernandes, Diana Rede, Cristina Delerue-Matos, Rachel Hurley, Luca Nizzetto, Cornelis A.M. van Gestel*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Abrasion of tire wear is one of the largest sources of microplastics to the environment. Although most tire particles settle into soils, studies on their ecotoxicological impacts on the terrestrial environment are scarce. Here, the effects of tire particles (<180 μm) on three ecologically relevant soil invertebrate species, the enchytraeid worm Enchytraeus crypticus, the springtail Folsomia candida and the woodlouse Porcellio scaber, were studied. These species were exposed to tire particles spiked in soil or in food at concentrations of 0.02%, 0.06%, 0.17%, 0.5% and 1.5% (w/w). Tire particles contained a variety of potentially harmful substances. Zinc (21 900 mg kg−1) was the dominant trace element, whilst the highest concentrations of the measured organic compounds were detected for benzothiazole (89.2 mg kg−1), pyrene (4.85 mg kg−1), chlorpyrifos (0.351 mg kg−1), HCB (0.134 mg kg−1), methoxychlor (0.116 mg kg−1) and BDE 28 (0.100 mg kg−1). At the highest test concentration in soil (1.5%), the tire particles decreased F. candida reproduction by 38% and survival by 24%, and acetylcholinesterase (AChE) activity of P. scaber by 65%, whilst the slight decrease in the reproduction of E. crypticus was not dose-dependent. In food, the highest test concentration of tire particles reduced F. candida survival by 38%. These results suggest that micro-sized tire particles can affect soil invertebrates at concentrations found at roadsides, whilst short-term impacts at concentrations found further from the roadsides are unlikely.

Original languageEnglish
Article number111495
Pages (from-to)1-9
Number of pages9
JournalEnvironmental Research
Volume201
Early online date13 Jun 2021
DOIs
Publication statusE-pub ahead of print - 13 Jun 2021

Bibliographical note

Funding Information:
A field emission scanning electron microscope (FE-SEM, Zeiss ULTRA plus, Carl Zeiss, Germany) was used to examine the particle size and morphology of tire particles. The particle size distribution was determined using a laser diffraction particle size analyzer Microtrac Bluewave at the University of Ljubljana, as described in the supporting information and in Selonen et al. (2020). The number of particles in the studied tire particle material was highest in the smallest size classes (mean 12.57 ?m; Fig. 1A), while in the volumetric distribution, particles between 80 and 110 ?m in size dominated (mean 102.9 ?m; Fig. 1B). The numerical distribution of the particles shows that about 50% of the particles in our test material were smaller than 10 ?m. The FE-SEM confirmed the results of the particle size distribution. The tire particles were semi-angular and irregularly shaped (Fig. 1C and D). Most of the particles were (numerically) in the range from 5 ?m to 100 ?m. The SEM micrographs revealed that many particles smaller than 10 ?m and even reaching the nanoscale were attached to larger particles (Fig. 1C and D). This may indicate that the number of ultrafine particles is easily underestimated in the measurements of tire particles.The authors are thankful for the financial support from the Netherlands Organisation for Scientific Research (NWO) [grant number ALWWW.2016.2] and the Research Council of Norway [grant number 271825/E50], in the frame of the collaborative international Consortium IMPASSE; the Maj and Tor Nessling Foundation (Finland); the Funda??o para a Ci?ncia e a Tecnologia (FCT)/the Minist?rio da Ci?ncia, Tecnologia e Ensino Superior (MCTES) through national funds (Portugal) [grant number LAQV - UIDB/QUI/50006/2020 and UIDP/50006/2020], PhD grant [Diana Rede and, grant number SFRH/BD/147 404/2019] and Post Doc grant [Virg?nia Cruz Fernandes, grant number SFRH/BPD/109153/2015]; and the Slovenian Research Agency (ARRS), through research programme ?Integrative zoology and speleobiology? [grant number P1-0184] and research project J1-2482, the infrastructural center Microscopy of biological samples and the ARRS PhD grant (Andraz Dolar). The authors declare no competing financial interest.

Funding Information:
The authors are thankful for the financial support from the Netherlands Organisation for Scientific Research (NWO) [grant number ALWWW.2016.2 ] and the Research Council of Norway [grant number 271825/E50 ], in the frame of the collaborative international Consortium IMPASSE; the Maj and Tor Nessling Foundation (Finland); the Fundação para a Ciência e a Tecnologia ( FCT )/the Ministério da Ciência, Tecnologia e Ensino Superior ( MCTES ) through national funds (Portugal) [grant number LAQV - UIDB/QUI/50006/2020 and UIDP/50006/2020 ], PhD grant [Diana Rede and, grant number SFRH/BD/147 404/2019] and Post Doc grant [Virgínia Cruz Fernandes, grant number SFRH/BPD/109153/2015]; and the Slovenian Research Agency (ARRS), through research programme “Integrative zoology and speleobiology” [grant number P1-0184 ] and research project J1-2482, the infrastructural center Microscopy of biological samples and the ARRS PhD grant (Andraz Dolar). The authors declare no competing financial interest.

Publisher Copyright:
© 2021 The Authors

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Keywords

  • Enchytraeid
  • Isopod
  • Soil ecotoxicology
  • Springtail
  • Tire wear particles

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