Session Chairs: Chelsea Rochman, University of Toronto; Sang Hee Hong, Korea Institute of Ocean Science and Technology; Won Joon Shim, Korea Institute of Ocean Science and Technology; Jennifer Lynch, National Oceanic and Atmospheric Administration; Hideshige Takada, Tokyo University of Agriculture and Technology; Hrissi Karapanagioti, University of Patras

This session will include laboratory and field research studies related to chemistry of plastic marine debris, including topics such as chemical characterization and weathering of plastic debris, chemical detection and quantification methods, and the fate of additives or accumulated ambient chemicals.

Plastic makes up the majority of marine debris. Plastics are synthetic polymers with diverse molecular structures. When they enter the environment, plastic undergoes physical, chemical and biological weathering which decreases its size via fragmentation and alters its original shape, chemical composition and surface characteristics. As such, chemical techniques are used to measure several variables related to plastic debris. Plastic particles in the micro- and nanometer scales are difficult to identify and quantify, and thus chemical techniques such as Raman and FTIR have become critical. Because plastics in the marine environment are made up of several types of polymers with diverse additive chemicals, chemistry techniques are used to identify and quantify the fate of chemicals from manufacturing.

For example, leaching of additive chemicals is facilitated by plastic fragmentation. Moreover, it is well known that plastics accumulate organic and metal pollutants from ambient seawater, including priority pollutants that have been banned for decades (i.e., PCBs and DDT). Scientists have used modeling, laboratory experiments and field research to help answer questions about how chemicals accumulate onto plastics, leach from plastics and affect organisms. For example, studies suggest the transfer of toxic chemicals (PCBs, PBDEs, and phthalates) from marine plastics to biota that ingest plastics can occur. This session aims to highlight studies that focus on: 1) analytical methods to detect, identify, and quantify synthetic polymers, including particles from the nano- to the macro-scale, in complex environmental media including sewage, sediments, and biological tissue, 2) physiochemical characterization of plastics, 3) weathering and fragmentation of plastic debris, 4) the fate of additive chemicals, monomers and oligomers in aquatic habitats and animals 6) the fate of sorbed contaminants in aquatic habitats and animals, and 7) toxicological effects of chemicals associated with plastic debris in marine organisms.



Nano-fragmentation of expanded polystyrene exposed to sunlight

presenting: Young Kyoung Song (Korea Institute of Ocean Science and Technology, South Korea); authors: Young Kyoung Song (Korea Institute of Ocean Science and Technology, South Korea), Soeun Eo (Korea Institute of Ocean Science and Technology), Sang Hee Hong (Korea Institute of Ocean Science and Technology), Won Joon Shim (Korea Institute of Ocean Science and Technology)

Fragmentation of micro- and nano-sized particles was qualitatively and quantitatively determined from the expanded polystyrene (EPS) exposed to sunlight for 9 months. The exposed EPS cubes (3×3 cm surface area) were sampled in duplicate at 2 (2M), 5 (5M) and 9 month (9M). The surface colour was changed from white to dark yellow during exposure. The fragmented particles at the top surface of the each cube directly exposed to sunlight were collected in 2 ml solution consisting of HPLC grade pure water with 0.1% tween 80 by sonication for 1 min. The collected particles in solution were sequentially filtered with 10 µm and 0.8 µm pore filter-paper. The mass of >10 µm EPS particles produced per EPS cube surface area (g/m2) significantly (p<0.05) increased according to exposure time; 0.1±0.1 g/m2 for control, 2.6±0.3 g/m2 for 2M, 3.9±0.4 g/m2 for 5M and 7.2±0.2 g/m2 for 9M. The mean and median size of >10 µm EPS particles measured by laser diffraction was 26-29 µm and 18-20 µm, respectively. The hydrodynamic diameter of the EPS particles in the filtrates of <0.8 µm pore filter-paper was 532 nm for 2M, 530 nm for 5M and 752 nm for 9M by dynamic laser scattering. Their particle abundances measured by nanoparticle tracking analysis were 1.8×109 particles/ml for 2M and 3.2×109 particles/ml for 2M and 9M. Two months of outdoor exposure of EPS were enough to produce a large number of micro- as well as nano-sized plastics.



presenting: Alexandra ter Halle (CNRS, France); authors: Alexandra ter Halle (CNRS, France), mingotaud anne francoise (CNRS), emile Perez (cnrs), olivier boyron (cnrs), julien gigault (cnrs), laurent jeanneau (cnrs)

Plastic pollution has been recognized by the scientific community as a major environmental problem. Since the 1950, mankind has produced over 8300 million metric tons of plastic1. Today 5040 million metric tons is already accumulated in landfills or in the natural environment 1.

Microplastic (1-5 mm) occurrence has been document in a fair number of places on earth, but there is a fundamental scientific knowledge gap towards understanding the mechanisms involved in plastic weathering and fragmentation in the environment.

Although degradation of polymers has been studied for a long time under laboratory condition, the weathering conditions occurring in a complex environment such as oceans lead to masses of questions. What is the extent of the plastic debris weathering2? What are the degradation processes? What is the influence of the biofilm3 and possible additives or adsorbed pollutants4, 5? In order to answer to some of these questions, we characterized plastic debris collected in the North Atlantic sub-tropical gyre during the campaign Expedition 7th Continent. The microplastics (1-5 mm) have been analyzed by electronic microscopy, infrared spectroscopy, size exclusion chromatography, calorymetry, pyrolysis-gaz chromatography-mass spectrometry (Py-GC-MS). Polyethylene was the predominant polymer found among microplastic. The debris showed a strong modification of their rate of crystallinity and their molar mass; indicating an advance state of degradation. The characterization of small microplastics (25-1000 µm) revealed the presence of great variety of polymers, going further than the expected polyethylene and polypropylene, the Py-GC-MS chemical fingerprint showed differences with the reference polymers, indicating a strong chemical modification of the polymer backbone.


Production of hydrocarbon gases from plastic at ambient temperatures

presenting: Sarah-Jeanne Royer (Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii at Manoa, United States); authors: Sarah-Jeanne Royer (Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii at Manoa, United States), Sara Ferrón (Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii at Manoa), Samuel T. Wilson (Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii at Manoa), David M. Karl (Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii at Manoa)

Over the past 50 years, polymer manufacturing has been increasing at a very fast pace, from 15 million tons in 1964 to 381 million tons in 2015 and is expected to double again over the next 20 years. Although plastic has widespread applications because of its favorable mechanical properties, thermal properties, stability and durability, it is still vulnerable to weathering and degradation processes. During these processes, plastic reacts with its environment and releases additives and polymer degradation products throughout its lifetime. Here we demonstrate that most commonly used plastics emit methane and ethylene when exposed to solar radiation at ambient temperatures. Polyethylene, which is globally the most produced and discarded synthetic polymer, is the most prolific emitter for both gases. Through an extensive time series of 212 days, we also show that emissions of methane, ethylene, ethane and polypropylene from virgin pellets of low-density polyethylene increase with time. Moreover, environmentally aged low-density polyethylene debris collected in the North Pacific Subtropical Gyre also emitted hydrocarbon gases when exposed to ambient solar radiation. Due to the longevity of plastics and the large amounts of plastic that persist in the environment, gas production may occur throughout the degradation lifetime of plastic and may represent a source of climate-relevant trace gases for an extended period of time.


Quantitative determination of sorbed and additive chemicals in microplastics from the Korean coastal waters

presenting: Sang Hee Hong (Korea Institute of Ocean Science and Technology, South Korea); authors: Sang Hee Hong (Korea Institute of Ocean Science and Technology, South Korea), Gi Myung Han (Korea Institute of Ocean Science and Technology), Lian Hong (Korea Institute of Ocean Science and Technology), Mi Jang (Korea Institute of Ocean Science and Technology), You Na Cho (Korea Institute of Ocean Science and Technology), Won Joon Shim (Korea Institute of Ocean Science and Technology)

Plastic debris and microplastics are complex mixtures of chemicals, including additives originally included in plastic products, and environmental contaminants sorbed from surrounding environments, which may impact the environments with which they come into contact. To evaluate the environmental risks of microplastics, the level of exposure and effects of not only the particles themselves but also their associated chemicals in the environment should be analyzed. However, limited field data is available on chemicals associated with microplastics, especially additive chemicals. This study investigated the levels and profiles of chemicals (both sorbed and additive chemicals) in various types of plastic particles (in size and shape) collected from the Korean coastal waters. Polychlorinated biphenyls (PCBs), organochlorine pesticides (DDTs, HCHs, and HCB), polycyclic aromatic hydrocarbons (PAHs), brominated flame retardants (PBDE and HBCD), phthalates, UV stabilizers, antioxidants were widely detected in microplastic samples. Except for expanded polystyrene (EPS) samples, phthalates showed the highest concentrations in most of size classes (< 1mm, 1 to 5 mm, and > 5 cm) and shapes (fragments, fibers, and pellets), followed by HBCDs, UV stabilizers, antioxidants, PAHs, PBDEs, PCBs and DDTs. EPS samples contained relatively high concentration of HBCDs and PAHs compared to fragments, pellets, and fibers. There was no significant difference in concentrations of the chemicals among size classes (< 1mm, 1 to 5 mm, and > 5 cm), which might be due to the diversity in their original plastic products, environmental exposure time, ect. This is the first detection of additive chemicals in microplastics smaller than 1 mm.


Persistent organic pollutants on plastic debris from the Great Pacific Garbage Patch: concentrations and prospective risk assessment

presenting: Qiqing Chen (The Ocean Cleanup, Netherlands); authors: Qiqing Chen (The Ocean Cleanup, Netherlands), Boyan Slat (The Ocean Cleanup Foundation), Francesco F. Ferrari (The Ocean Cleanup Foundation), Anna Schwarz (The Ocean Cleanup Foundation), A. A. Koelmans (Wageningen University & Research)

Plastics are widely distributed in the world’s oceans, however, the variability in concentrations of plastic-bound Persistent Organic Pollutants (POPs) is poorly understood. Here we report concentrations of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), and hexabromocyclododecane (HBCD) on oceanic plastics from the surface layer of the Great Pacific Garbage Patch.

Marine plastic samples composed of nets and ropes showed relatively higher PAHs and PCBs concentrations, while hard plastic and pellet samples had higher PBDEs concentrations. HBCD concentrations were relatively constant among different types. Most samples showed a pyrogenic PAH signature. PCBs were predominated by penta- to hepta-chlorinated congeners and 42% of our samples had PCB congener patterns similar to those of a common additive. No trends between PAHs, PCBs and PBDEs concentrations and plastic debris size were found; except for HBCD, which showed higher concentrations in smaller particles (the so-called microplastics).

Concentrations of POPs were equal to or higher than literature values for marine sediment, but significantly lower after normalization on sediment organic matter content. We used sediment Environmental Quality Standard (EQS) values as a proxy to assess toxicity profiles for oceanic plastics contaminated with POPs. 84% of the plastic samples had at least one chemical exceeding sediment threshold effect levels.

Furthermore, our surface trawls collected far more plastic than biomass, indicating that GPGP organisms feeding opportunistically upon floating particles may have plastics as a major component of their diet. If gradients for POPs mass transfer from plastic to predators exist, GPGP plastics may play a role in transferring POPs to certain marine organisms.


Dynamics of chemical transfer on microplastic in gut

presenting: Nur Hazimah Mohamed Nor (Wageningen University & Research, Netherlands); authors: Nur Hazimah Mohamed Nor (Wageningen University & Research, Netherlands), Fani Tsaroucha (Wageningen University & Research), Yue Chen (Wageningen University & Research), Wanling Huang (Wageningen University & Research), Albert A. Koelmans (Wageningen University & Research)

Microplastics acting as a vector for bioaccumulation of hydrophobic organic chemicals (HOCs) is a long standing hypothesis within the research on plastic debris. Previous studies have demonstrated that microplastics contributed to 1-2 times increase or decrease in bioaccumulation of HOCs. These studies were mostly in-vivo with exposure scenarios favouring uptake of chemicals from microplastic, whereas in the environment, chemical uptake by plastic might also occur. Furthermore, the exact transfer kinetics of the HOCs between the ingested microplastics and organisms in the gut cannot be quantified in such tests. Simulating gastrointestinal conditions with artificial gut fluids is an experimental technique to assess bioavailability of chemicals in an organism and can better test the sorption mechanisms. The uptake of chemicals by microplastics from contaminated food has not been studied before. Here, we demonstrate different exposure scenarios of microplastics in artificial gut fluids and transfer of a range of HOCs to/from these microplastics. The data was modelled with a non-equilibrium dynamic model, accounting for reversible transfer of HOCs between microplastics, water, gut fluid and natural food components under different relevant uptake scenarios. Chemical transfer half-lives range between hours and days, and we show how organisms with different gut residence times will be affected differently by the ingestion of microplastic. In nature, the levels of chemical mixtures in the biota and microplastics may not be at equilibrium and direction of transfer depends on the fugacity in different compartments.


Study of the leaching of additive from microplastics using an in vitro enzymatic digestion model

presenting: Ludovic Hermabessiere (Anses, Laboratoire de sécurité des aliments, France); authors: Ludovic Hermabessiere (Anses, Laboratoire de sécurité des aliments, France), José-Luis Zambonino-Infante (Ifremer, Centre de Bretagne, LEMAR UMR 6539), Justine Receveur (Cedre), Charlotte Himber (Anses, Laboratoire de sécurité des aliments), Ika Paul-Pont (c Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER), Camille Lacroix (Cedre), Alexandre Dehaut (Anses, Laboratoire de sécurité des aliments), Ronan Jezequel (Cedre), Philippe Soudant (Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER), Guillaume Duflos (Anses, Laboratoire de sécurité des aliments)

Plastics debris, including microplastics, are nowadays recovered in every marine compartments. Many studies have been conducted on desorption of pollutants from microplastics but few were focused on plastic additives. If leaching of some plastic additives has been recently demonstrated in water, no work has yet explored leaching of plastic additives after ingestion of microplastics by marine organisms and exposed to digestion. However such mechanism could have potential adverse effects on the host. In this work, the development of an in vitro enzymatic model has been performed to study the leaching of a common plastic additive found in polyethylene (PE). Lab made Irgafos 168 ® loaded PE fragments (PE-Ir) (20 – 100 µm) were used in the study. The in vitro enzymatic model mimics the main enzymes from the stomach and pancreas of vertebrates: pepsin and trypsin respectively. Moreover, a pancreatic extract of enzymes (including amylase, lipase and trypsin) acting in the intestinal lumen was also used. PE-Ir particles (5 MPs/mL) were exposed to the three digestive conditions for 8h at two different temperatures, 20°C and 37°C, representing fish and human models, respectively. The leaching of Irgafos 168 ® and enzyme specific activities were recorded over time using GC-MS/MS and spectrometric assays, respectively.

This work could provide some relevant insights on the transfer of common plastic additives to marine organisms.


Occurrence of wide-range of additives in marine plastics and their exposure to marine organisms

presenting: Hideshige Takada (Tokyo University of Agric. & Techno., Japan); authors: Hideshige Takada (Tokyo University of Agric. & Techno., Japan), Rei Yamashita (Tokyo University of Agric. & Techno.), Bee Yeo (Tokyo University of Agric. & Technol.), Hiroya Sato (Tokyo University of Agric. & Technol.), Nagano Hiki (Tokyo University of Agric. & Technol.), Tae Ohgaki (Tokyo University of Agric. & Technol.), Peter Ryan (University of Cape Town), David Hyrenbach (Hawaii Pacific University), Denise Hardesty (CSIRO), Lauren Roman (University of Tasmania)

Additives are essential components of plastic products. Some of them are hazardous to marine organisms and human. They can be also utilized as indicators of plastic-mediated chemical exposure to marine organisms. The present study measured wide range of additives including plasticizers (phthalates), UV absorbers (benzotriazoles and benzophenones), flame retardants (PBDEs, DBDPE, HBCDs, and tetrabromo bisphenol A) in large plastic fragments and microplastic fragments and pellets on sandy beaches, and buoyant microplastics in coastal and open ocean, plastic fragments from fulmar from the Netherland, and preen gland oil from seabirds globally collected. UV absorbers, especially benzotriazoles, are widely detected in large plastic fragments on the beaches and plastic fragments in seabirds’ stomach. They are also detected in preen gland oil from some species of seabirds such as black footed albatross from Tern Island, Hawaii. Brominated flame retardants such as BDE-209 and DBDPE were also detected in the plastic fragments from the stomach of fulmar. They are also detected in preen gland oil from several species of seabirds from some locations in the world such as Hawaii, Western Australia, and Marion Island. These suggest transfer of plastic additives from ingested plastics to the tissue of seabirds. Among beached microplastics, plastic fragments contained more BDE-209 than pellets. In buoyant microplastics even from open ocean, BDE-209 was significantly detected. This means that hydrophobic additives, i.e., BDE-209, is retained in microplastics even after fragmentation and suspension in seawater. These hydrophobic additives could be source of chemical exposure to small marine organisms in remote ecosystem.


Microplastic occurrence in La Paz Bay (Mexico) and phthalate esters concentration in two resident filter-feeder species

presenting: Matteo Galli (University of Siena, Italy); authors: Matteo Galli (University of Siena, Italy), Matteo Baini (University of Siena), Tabata Olavarrieta Garcia (Autonomous University of Baja California Sur), Jorge Urbán Ramírez (Autonomous University of Baja California Sur), Dení Ramírez-Macías (Tiburon Ballena Mexico proyecto de ConCiencia Mexico AC), Cristina Panti (University of Siena), Tania Martellini (University of Florence), Alessandra Cincinelli (University of Florence), Maria Cristina Fossi (University of Siena)

Release of hazardous chemicals from floating plastic debris may cause toxicological effects on marine species. Phthalate esters (PAEs) are suggested to act as endocrine disruptors even at low concentrations. Large filter-feeding species, characterized by a long life span and a continue feeding activity, are potentially chronically exposed to these contaminants both leaching from ingested plastics and from their degradation and through the food chain. In this study, we evaluate the abundance and the polymer characterizations by FTIR spectroscopy of microplastics collected through surface-trawling plankton nets in the Bay of La Paz, Mexico. The increasing human pressure in this area is giving rise to chemical pollution from urban wastewaters, agriculture and maritime activities. Presence of six PAEs as plastic tracers has been assessed in neustonic samples and in skin biopsy samples of fin whales (Balaenoptera physalus) and whale sharks (Rhyncodon typus) by GC-qMS. Sixty six per cent of the net tows contained plastics with a maximum of 0.22 items/m3. Neustonic samples showed different fingerprint of PAEs, indicating heterogeneous levels and spatial patterns in the investigated area. Diethylhexyl phthalate presented the highest values in all samples analyzed, with a concentrations ranged from <BDL to 29.97 ug/g d.w.. Overall, data obtained suggest that filter-feeder organisms are exposed to the accumulation of compounds released by plastics. The low concentrations of floating microplastics found contrasts with the levels of PAEs measured in biological samples, which are in the same order of those measured in filter feeder species from other polluted basins, such as Mediterranean Sea. This could be related both to the high ingestion rate of plastic particles and to the ingestion of plastic debris, such as macroplastics.


Validation of ATR FT-IR to identify polymers of ingested plastic marine debris

presenting: Jennifer Lynch (Chemical Sciences Division, United States); authors: Jennifer Lynch (Chemical Sciences Division, United States), Melissa Jung (College of Natural and Computational Sciences), Sara Orski (Material Science and Engineering Division), Viviana Rodriguez C. (Material Science and Engineering Division), Kathryn Beers (Material Science and Engineering Division), George Balazs (Pacific Islands Fisheries Science Center), Thierry Work (U.S. Geological Survey), Kayla Brignac (School of Ocean, Earth Science, and Technology), Sarah-Jeanne Royer (Daniel K. Inouye Center for Microbial Oceanography: Research and Education), Brenda Jensen (College of Natural and Computational Sciences)

Polymer identification has become an integral part of plastic debris monitoring to help determine debris sources, fate and impact. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) is commonly used for polymer identification. We optimized and validated this fast, simple and accessible method to identify plastic found in the guts of pelagic Pacific sea turtles (≥5 mm on largest side) or on Hawaiian beaches (≥1 cm). An in-house spectral library was created using consumer goods of resin codes #1-6 and several #7 polymers. These spectra were similar to purer plastics, including National Institute of Standards and Technology Standard Reference Materials (SRMs), scientifically-sourced and raw manufactured polymers. A blind test of 11 consumer goods, float tests in various densities of diluted ethanol, and an inter-laboratory comparison with high temperature size exclusion chromatography with multiple detectors confirmed that ATR FT-IR could differentiate #1-6 and several #7 polymers. Distinguishing high-density (HDPE) and low-density polyethylene (LDPE) was challenging, but we present a clear step-by-step guide that allowed identification of 78% of ingested PE samples. When coupled with an ethanol float test, 92% of beach PE samples could be distinguished. Optimal cleaning methods for ingested plastics were wiping with water or cutting. These preferred methods eliminated the use of hazardous chemical treatment and preserved the pieces for future chemical analysis. The ATR FT-IR method was highly successful, resulting in the ability to identify 97% of ingested plastics from sea turtles and 99% of Hawaiian beach debris. Results and implications of those studies are presented elsewhere at this meeting. This study presents these standardized methods and will discuss future production of SRMs.


Automated Identification and Quantification of Microplastics by FTIR Imaging and Image Analysis

presenting: Sebastian Primpke (Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Biologische Anstalt Helgoland, Germany); authors: Sebastian Primpke (Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Biologische Anstalt Helgoland, Germany), Claudia Lorenz (Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Biologische Anstalt Helgoland), Richard Rascher-Friesenhausen (Fraunhofer MEVIS), Gunnar Gerdts (Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Biologische Anstalt Helgoland)

In the last decades the pollution of the oceans with plastic particles smaller than 5 mm, called microplastics has moved into the focus of science and governments. The analysis of particles especially <500 µm in size is a challenging field. These particles cannot be handled well manually and are therefore often concentrated on filters or meshes. By common FTIR microscopy the filter will be inspected visually and particles of interest marked for the following analysis. The manual selection process is prone to human bias, which can be overcome by FTIR imaging. Here, the complete filter area is mapped by FTIR using focal-plane-array (FPA) detectors, which collect several hundred spectra within one measurement for a large area. Each particle on the filter is therefore examined by FTIR spectroscopy. The results of this imaging can be either analyzed manually by the application of integrals for certain regions of the spectrum or automated. While the manual process is time consuming and prone to human bias we present an automated approach, which is totally impartial. With this process it is possible to analyze measurement files containing up to 1.8 million single spectra by library searches against an optimized database of different synthetic and natural polymers. The high quality data generated allowed image analysis, giving information for the particle size distribution for each polymer type as well as their distribution on the filter. All data was collected with relative ease even for complex sample matrices like (deep sea) sediments, waste water treatment plants, plankton samples and arctic ice cores. This approach has significantly decreased the expenditure of time for the interpretation of FTIR-imaging data and increased the quality of the generated data. The approach allows the standardization of microplastic analysis.


Plastic debris can be both a source and sink for flame retardants in ring-billed gulls (Larus delawarensis)

presenting: Clara Thaysen (University of Toronto, Canada); authors: Clara Thaysen (University of Toronto, Canada), Manon Sorais (Université du Québec à montréal), Jonathan Verreault (Université du Québec à montréal), Miriam Diamond (University of Toronto), Chelsea Rochman (University of Toronto)

Plastic debris has been recognized as a contaminant of concern for wildlife because it can act as a vector for hazardous chemicals. The theory that ingested plastic can act as a source of chemicals to wildlife has been tested by several researchers via laboratory experiments, mathematical models, and observational studies in nature. Several laboratory experiments have demonstrated chemical transfer via ingested plastic, while mathematical models find that the transfer depends on the initial concentration in the plastic, in the animal, and gut retention time. These models suggest that plastics with low chemical concentrations could act as a sink for chemical pollutants in organisms. As such, results from the field can be mixed. Here, we test the hypothesis of chemical transfer via ingested plastic in a colony of freshwater ring-billed gulls from the St. Lawrence River in Québec, Canada. Unlike previous studies, we examine a colony that resides in a heavily urbanised and industrialized habitat that was shown to be a hotspot for flame retardant (FR) chemicals. We measured plastic ingestion and the concentration of a series of FRs on both ingested plastic and plasma. We found that 29 of 44 of the gulls examined contained ingested plastic, and FRs were detected on all ingested plastic samples. We examined the body burden of 25 of these individuals and detected FRs in all plasma samples. There were weak, but significant relationships between the amount of plastic ingested and some FRs in plasma. Relationships between the amount and identities of FRs in plastic and plasma suggest that ingested plastic in this colony can act as both a source and sink for these chemicals. These results suggest that there are many sources of FRs to these gulls and that the role of ingested plastics can be complex.