Microplastic-mediated transport of PCBs? A depuration study with Daphnia magna.

Zandra Gerdes,Elena Gorokhova,Martin Ogonowski,Caroline Ek,Inna Nybom,Andreas Barth,Margaretha Adolfsson-Erici,Amitava Mukherjee

doi:10.1371/journal.pone.0205378

Zandra Gerdes, Elena Gorokhova + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0205378

Copy DOI

Abstract

The role of microplastic (MP) as a carrier of persistent organic pollutants (POPs) to aquatic organisms has been a topic of debate. However, the reverse POP transport can occur if relative contaminant concentrations are higher in the organism than in the microplastic. We evaluated the effect of microplastic on the PCB removal in planktonic animals by exposing the cladoceran Daphnia magna with a high body burden of polychlorinated biphenyls (PCB 18, 40, 128 and 209) to a mixture of microplastic and algae; daphnids exposed to only algae served as the control. As the endpoints, we used PCB body burden, growth, fecundity and elemental composition (%C and %N) of the daphnids. In the daphnids fed with microplastic, PCB 209 was removed more efficiently, while there was no difference for any other congeners and ΣPCBs between the microplastic-exposed and control animals. Also, higher size-specific egg production in the animals carrying PCB and receiving food mixed with microplastics was observed. However, the effects of the microplastic exposure on fecundity were of low biological significance, because the PCB body burden and the microplastic exposure concentrations were greatly exceeding environmentally relevant concentrations.

Highlights

Microplastic (MP, particles < 5 mm) are an emerging contaminant in our environments
We explored whether exposure to microplastics (1) facilitates depuration of polychlorinated biphenyls (PCBs), similar to the sought remediation effect by adding activated carbon to contaminated sediments [24], and (2) alleviates effects of the PCB exposure on growth and elemental composition in the model filter-feeder D. magna (Straus, 1820)
The commonly reported microplastic concentrations in situ are much lower than those used in our study [37], and environmental zooplankton samples contain 20-fold to four orders of magnitude less PCBs than our postdepuration daphnids [38,39,40]

Summary

Introduction

Concerns have been expressed that microplastic may compromise feeding of aquatic organisms and facilitate transfer of organic pollutants in food webs [1,2]. These small plastic fragments are being ingested by a variety of organisms, e.g. fish [3], bivalves [4], polychaetes [5], and zooplankton [6], with still unknown consequences.

Methods

Results

Discussion

Conclusion