Dear Marmam colleagues, I trust everyone is doing welland staying safe in these challenging times. I am pleasedto share a new article on “Modeling theBioaccumulation and Biomagnification Potential of Microplastics in a CetaceanFoodweb of the Northeastern Pacific: A Prospective Tool to Assess the RiskExposure to Plastic Particles,” which is a contribution presenting the development ofa cetacean-foodweb bioaccumulation model for microplastics to understand thebioaccumulation and biomagnification behavior of microplastics in top predatorssuch as marine mammals and support ecotoxicological risk assessments of these emergingand pervasive micropollutants. This article is an Open Access paperand can be found at the following link: https://www.frontiersin.org/article/10.3389/fmars.2020.566101 Full details and abstract: Citation: Alava, J.J. 2020,Modeling the Bioaccumulation and Biomagnification Potential of Microplastics ina Cetacean Foodweb of the Northeastern Pacific: A Prospective Tool to Assessthe Risk Exposure to Plastic Particles. Frontiers in Marine Science7:566101. doi: 10.3389/fmars.2020.566101 https://doi.org/10.3389/fmars.2020.566101 *Correspondence:Juan José Alava, j.alava@oceans.ubc.ca Published: 22 September 2020. Abstract Microplastics (MPs)can readily be ingested by marine organisms. Direct ingestion and trophictransfer are likely to be the main pathway for microplastics to bioaccumulatein upper trophic level organisms. Bioaccumulation potential of MPs in marinemammalian foodwebs is scarcely known. To understand whether microplasticsbioaccumulate in marine mammals, a bioaccumulation model for MPs was developedfor the filter-feeding humpback whale and fish-eating resident killer whalefoodwebs of the Northeastern Pacific. Applying three concentration scenariosfor MPs by entering observed water and sediment concentrations as input data(low, high, and moderate scenarios), and tested under two different eliminationrates (kE) for zooplankton, the model predictedspecies-specific and foodweb-specific bioaccumulation potential. Thepredator-prey biomagnification factor (BMFTL, used to assessthe ratio of the MP concentration in predator to that in prey adjusted to thedifference of trophic levels), involving cetaceans, appeared to be not onlylower than one or equal to one (BMFTL ≤ 1 as in residentkiller whale/Chinook salmon), but also BMFTL > 1 in somepredator-prey relationships (humpback whale/zooplankton). Depending on themagnitude of abiotic concentrations used in the modeling, the trophicmagnification factor (TMF) regression analyses over time showed lack ofevidence for trophic magnification as the magnification was independent of thetrophic level, indicating no changes (TMF = 1; p > 0.05), and trophicdilution (TMF < 1; p < 0.05) due to the decrease in MPconcentrations as the trophic level increased. Projected biomagnification insimplified foodwebs revealed no significant increase in concentrations as thetrophic level increased (TMF = 1; p > 0.05), following 100–365 days.Compared to the high biomagnification behavior of persistent organic pollutantsin marine foodwebs, scarce biomagnification capacity of microplastic waspredicted in the cetacean foodwebs. Notwithstanding, the moderate to highmicroplastic bioaccumulation predicted in some lower trophic level marine organismshighlights the health risks of toxic exposure to marine fauna strongly relyingon fish and coastal communities highly dependent on seafood. This modeling workprovides a tool to assess the bioaccumulation potential and impact ofmicroplastics in the marine environment to support risk assessment and informplastic waste management. Keywords: microplastics,exposure, elimination rate, bioaccumulation, trophic magnification, southernresident killer whale, humpback whale, marine mammals https://www.frontiersin.org/articles/10.3389/fmars.2020.566101/full?&utm_sou... Wishing you all well and stay safe. Juan Jose Alava -------------------- Juan Jose Alava, PhD. Research Associate, Nippon Foundation-Ocean Litter Project Principal Investigator, Ocean Pollution Research Unit (OPRU) Institute for the Oceans and Fisheries Faculty of Science, The University of British Columbia AERL 2202 Main Mall | Vancouver, BC V6T 1Z4 Canada http://oceans.ubc.ca/juan-jose-alava/ https://www.researchgate.net/profile/Juan_Jose_Alava/contributions?ev=prf_ac... Adjunct Professor Resource and Environmental Management, Faculty of Environment, Simon Fraser University 8888 University Drive, Burnaby, British Columbia V5A 1S6,Canada E-mail: jalavasa@sfu.ca