Event Title

Why microplastics do not transfer persistent organic pollutants through aquatic food webs

Presentation Abstract

Microplastic particles are ubiquitous in the world's oceans, may be ingested by marine organisms, and are enriched in hydrophobic organic chemicals relative to their surrounding aqueous environment. These three well documented observations often lead to speculation that marine microplastics serve as an important vector to pump persistent organic pollutants (POPs) such as PCBs and flame retardants into higher levels of aquatic food webs. Since field-collected microplastic particles contain relatively high concentrations of many POPs, even in remote oceanic environments, it is tempting to view them as POPs-enriched packets that efficiently deliver toxins to shellfish and finfish. In fact, one of the major justifications for legislative action against the use of microplastics in consumer products is the potential risk of increasing bioaccumulation in receiving waters. Despite this widespread conjecture, both theory and experiments demonstrate that microplastics play almost role either as a reservoir for pollutants or as a vector for pollutant transfer. In this paper, we will use field measurements of microplastic and POPs concentrations in the Salish Sea together with poly-parameter chemical partitioning, pharmacokinetic, and plankton grazing models to quantitatively explore potential microplastic-bioaccumulation relationships. Such models are driven by the thermodynamic distribution of hydrophobic chemicals between water, microplastics (both clean and biofilm-coated), and the digestive tract of marine organisms, as well as by the relative abundance of microplastic particles within the complex mixture of natural particles encountered in coastal waters.

Session Title

Microplastic Pollution: a Troubling, Yet Tractable, Conservation Priority in the Salish Sea

Conference Track

SSE13: Plastics

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE13-463

Start Date

5-4-2018 4:00 PM

End Date

5-4-2018 4:15 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 5th, 4:00 PM Apr 5th, 4:15 PM

Why microplastics do not transfer persistent organic pollutants through aquatic food webs

Microplastic particles are ubiquitous in the world's oceans, may be ingested by marine organisms, and are enriched in hydrophobic organic chemicals relative to their surrounding aqueous environment. These three well documented observations often lead to speculation that marine microplastics serve as an important vector to pump persistent organic pollutants (POPs) such as PCBs and flame retardants into higher levels of aquatic food webs. Since field-collected microplastic particles contain relatively high concentrations of many POPs, even in remote oceanic environments, it is tempting to view them as POPs-enriched packets that efficiently deliver toxins to shellfish and finfish. In fact, one of the major justifications for legislative action against the use of microplastics in consumer products is the potential risk of increasing bioaccumulation in receiving waters. Despite this widespread conjecture, both theory and experiments demonstrate that microplastics play almost role either as a reservoir for pollutants or as a vector for pollutant transfer. In this paper, we will use field measurements of microplastic and POPs concentrations in the Salish Sea together with poly-parameter chemical partitioning, pharmacokinetic, and plankton grazing models to quantitatively explore potential microplastic-bioaccumulation relationships. Such models are driven by the thermodynamic distribution of hydrophobic chemicals between water, microplastics (both clean and biofilm-coated), and the digestive tract of marine organisms, as well as by the relative abundance of microplastic particles within the complex mixture of natural particles encountered in coastal waters.