Hello MARMAM Community, My co-authors and I are pleased to announce our new paper "The deep dive of organohalogen compounds: Bioaccumulation in the top predators of mesopelagic trophic webs, pygmy and dwarf sperm whales, from the Southwestern Atlantic ocean" recently published on Chemosphere! You can access it here: https://doi.org/10.1016/j.chemosphere.2023.140456 *Abstract:* *Kogia sima* and *Kogia breviceps* are apex predators of mesopelagic trophic webs being far from most anthropogenic threats. However, chemical pollutants and naturally synthesized compounds may travel long distances. This study aimed to use kogiid whales as sentinels of mesopelagic trophic webs in the Southwestern Atlantic Ocean. Persistent organic pollutants (POPs), e.g., polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, mirex, hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBB), and the naturally produced methoxylated BDE (MeO-BDEs) were determined in the blubber of 16 *K. sima* and 15 *K. breviceps*. Among the organochlorine compounds, DDTs were the main group found in* K. sima* and in *K. breviceps* (1636.6 and 3983.3 ng g− 1 lw, respective medians), followed by PCBs (425.9 and 956.1 ng g− 1 lw, respectively), mirex (184.1 and 375.6 ng g− 1 lw, respectively), and HCB (132.4 and 340.3 ng g− 1 lw, respectively). As for the organobromine, the natural MeO-BDEs were predominant (1676.7 and 501.6 ng g− 1 lw, respectively), followed by PBDEs (13.6 and 10.3 ng g− 1 lw, respectively) and PBEB (2.2 and 2.9 ng g− 1 lw, respectively). In general, POPs concentration was higher in *K. breviceps* than in *K. sima*. Conversely, MeO-BDEs concentration was higher in *K. sima* than in *K. breviceps*. Differences in concentrations in these sympatric odontocetes were attributed to distinct species, sampling sites, and biological parameters and suggest some level of niche segregation. It is noteworthy the long-range reach and bioaccumulation of these synthetic compounds in an unexplored habitat, that present an increasing economic interest. Please, let me know if you have any comments! Kind regards, *MSc. Nara de Oliveira Ferreira* _____________________________________________________________ *Laboratório de Mamíferos Aquáticos e Bioindicadores (MAQUA -UERJ)* Mestre em Ecologia e Evolução - Universidade do Estado do Rio de Janeiro Doutoranda em Biofísica - Universidade Federal do Rio de Janeiro Contato: + 55 21 98585.9916