Dear colleagues, On behalf of my co-authors and I, we're pleased to announce the publication of our paper: “Levels of Polychlorinated Biphenyls Are Still Associated with Toxic Effects in Harbor Porpoises (Phocoena phocoena) Despite Having Fallen below Proposed Toxicity Thresholds”. Abstract: Polychlorinated biphenyls (PCBs) are toxic, persistent, and lipophilic chemical compounds that accumulate to high levels in harbor porpoises (Phocoena phocoena) and other cetaceans. It is important to monitor PCBs in wildlife, particularly in highly exposed populations to understand if concentrations are declining and how levels relate to toxicological thresholds and indices of health like infectious disease mortality. Here we show, using generalized additive models and tissue samples of 814 U.K.-stranded harbor porpoises collected between 1990 and 2017, that mean blubber PCB concentrations have fallen below the proposed thresholds for toxic effects. However, we found they are still associated with increased rates of infectious disease mortality such that an increase in PCB blubber concentrations of 1 mg kg–1 lipid corresponds with a 5% increase in risk of infectious disease mortality. Moreover, rates of decline and levels varied geographically, and the overall rate of decline is slow in comparison to other pollutants. We believe this is evidence of long-term preservation in the population and continued environmental contamination from diffuse sources. Our findings have serious implications for the management of PCB contamination in the U.K. and reinforce the need to prevent PCBs entering the marine environment to ensure that levels continue to decline. The paper is available to read or download at: https://doi.org/10.1021/acs.est.9b05453<https://doi.org/10.1016/j.scitotenv.2019.134835> If you have any questions or would like a copy please do not hesitate to contact me via email at rosie.williams@ioz.ac.uk<mailto:rosie.williams@ioz.ac.uk> Kind regards, Rosie Rosie Williams Zoological Society of London & Brunel University London Twitter: @RosieSWilliams1 Rosie Williams PhD Student - London NERC DTP Brunel University & Zoological Society of London https://www.zsl.org/science/users/rosie-williams @RosieSWilliams1<https://twitter.com/RosieSWilliams1?lang=en-gb> _________________________________________________________________________ The Zoological Society of London is incorporated by Royal Charter - Registered Charity in England and Wales no. 208728. Principal Office England - Company Number RC000749 - Registered address Regent's Park, London, England NW1 4RY _________________________________________________________________________ This e-mail has been sent in confidence to the named addressee(s). If you are not the intended recipient, you must not disclose or distribute it in any form, and you are asked to contact the sender immediately. Views or opinions expressed in this communication may not be those of The Zoological Society of London and, therefore, The Zoological Society of London does not accept legal responsibility for the contents of this message. The recipient(s) must be aware that e-mail is not a secure communication medium and that the contents of this mail may have been altered by a third party in transit. If you have any issues regarding this mail please visit: https://www.zsl.org/about-us/contact-us