Dear members of the MARMAM community, My co-authors and I are pleased to announce our recent open-access publication in *Environmental Science & Technology*: *Varying diet composition causes striking differences in legacy and emerging contaminant concentrations in killer whales across the North Atlantic*. https://doi.org/10.1021/acs.est.3c05516 You can find a recap of our main findings aimed at the public, as well as an infographic recap of the paper, here: https://whalescientists.com/north-atlantic-killer-whales-toxic-menus/ Here is the abstract of the paper: Lipophilic persistent organic pollutants (POPs) tend to biomagnify in food chains, resulting in higher concentrations in species such as killer whales (Orcinus orca) feeding on marine mammals compared to those consuming fish. Advancements in dietary studies include the use of quantitative fatty acid signature analysis (QFASA) and the differentiation of feeding habits within and between populations of North Atlantic (NA) killer whales. This comprehensive study assessed the concentrations of legacy and emerging POPs in 162 killer whales from across the NA. We report significantly higher mean levels of polychlorinated biphenyls (PCBs), organochlorine pesticides, and flame retardants in Western NA killer whales compared to eastern NA conspecifics. Mean ∑PCBs ranged from ~100 mg/kg lipid weight (lw) in the Western NA (Canadian Arctic, Eastern Canada) to ~50 mg/kg lw in the mid-NA (Greenland, Iceland), to ~10 mg/kg lw in the Eastern NA (Norway, Faroe Islands). The observed variations in contaminant levels were strongly correlated with diet composition across locations (inferred from QFASA), emphasizing that diet, and not environmental variation in contaminant concentrations among locations, is crucial in assessing contaminant-associated health risks in killer whales. These findings highlight the urgency for implementing enhanced measures to safely dispose of POP-contaminated waste, prevent further environmental contamination, and mitigate the release of newer and potentially harmful contaminants. Please reach out to me if you have questions/comments: anais.remili@mail.mcgill.ca. Cheers, Anais Remili, PhD Postdoctoral researcher at McGill University Editor-in-chief of Whale Scientists