Dear MARMAM Community, My co-authors and I are pleased to share our new paper with you entitled "Franciscana dolphins, *Pontoporia blainvillei*, as environmental sentinels of the world's largest mining disaster: Temporal trends for organohalogen compounds and their consequences for an endangered population" recently published in Environmental Pollution. We discuss the temporal trends of organohalogen compounds in a genetically and geographically isolated population of franciscana dolphins affected by the largest environmental disaster in Brazil. You can access the article following the link: https://www.sciencedirect.com/science/article/abs/pii/S026974912200584X?via%... Abstract: On November 5th, 2015, the Fundão dam collapsed in Minas Gerais, southeastern Brazil, releasing millions of cubic meters of mud containing mining residue into the Doce River. Two weeks later, the mud arrived to the marine environment, triggering changes in franciscana dolphin habitat, *Pontoporia blainvillei*, from Franciscana Management Area Ia. This is an isolated population of the most endangered cetacean species in the South Atlantic Ocean. Organohalogen compounds <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/organohalogen-compound> (OHCs) may pose a threat to this endangered population because of their endocrine disrupting properties. Hence, this study sought to determine if there were differences in the bioaccumulation profile of OHC (PCBs, DDTs, Mirex, HCB <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hexachlorobenzene> , HCHs <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hch>, PBDEs <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/pbde>, PBEB, HBBZ and MeO-BDEs) in franciscana dolphins before and after dam collapse and to build a temporal trend. Blubber of 33 stranded individuals was collected in Espírito Santo state for organohalogen <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/organohalogen> assessment between 2003 and 2019. Differences were found between franciscana dolphins collected prior to and after the disaster. Additionally, significant temporal trends for organochlorine pesticides <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/organochlorine-pesticide> and natural and anthropogenic organobromine were detected. The increase in pesticide concentrations after 2015 is suggestive of their reavailability in the environment. The decline in organobromine over time could be due to their debromination in the marine environment and alterations in the composition of their natural producers. PCBs remained stable during the period of the study. Our findings show an increase in endocrine disruptor <https://www.sciencedirect.com/topics/earth-and-planetary-sciences/endocrine-disruptor> concentrations, which is of great concern for this endangered population. Please, do not hesitate to contact us! 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