Dear colleagues, On behalf of my co-authors and I, I’m pleased to announce the publication of our paper: “Juvenile harbor porpoises in the UK are exposed to a more neurotoxic mixture of polychlorinated biphenyls than adults”. Abstract: Polychlorinated biphenyls (PCBs) are a group of 209 persistent and bio-accumulative toxic pollutants present as complex mixtures in human and animal tissues. Harbor porpoises accumulate some of the highest levels of PCBs because they are long-lived mammals that feed at a high trophic level. Studies typically use the sum of a suite of individual chlorobiphenyl congeners (CBs) to investigate PCBs in wildlife. However, toxic effects and thresholds of CB congeners differ, therefore population health risks of exposure may be under or over-estimated dependent on the congener profiles present. In this study, we found congener profiles varied with age, sex and location, particularly between adult females and juveniles. We found that adult females had the highest proportions of octa-chlorinated congeners whilst juveniles had the highest proportions of tri- and tetra-chlorinated congeners. This is likely to be a consequence of pollutant offloading between mothers and calves during lactation. Analysis of the individual congener toxicities found that juveniles were exposed to a more neurotoxic CB mixture at a time when they were most vulnerable to its effects. These findings are an important contribution towards our understanding of variation in congener profiles and the potential effects and threats of PCB exposure in cetaceans. The paper is open access and available to read or download at: https://doi.org/10.1016/j.scitotenv.2019.134835 If you have any questions please do not hesitate to contact me via email at rosie.williams@ioz.ac.uk Kind regards, Rosie Rosie Williams Zoological Society of London & Brunel University London Twitter: @RosieSWilliams1 _________________________________________________________________________ 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