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 (2018 : Seattle, Wash.)
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
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Microplastics--Salish Sea (B.C. and Wash.); Marine organisms--Effect of water pollution on--Salish Sea (B.C. and Wash.); Persistent pollutants--Bioaccumulation--Salish Sea (B.C. and Wash.); Food chains (Ecology)--Salish Sea (B.C. and Wash.)
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
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.
