POPs concentrations in cetaceans stranded along the agricultural coastline of SE Spain show lower burdens of industrial pollutants in comparison to other Mediterranean cetaceans

Endocrine-Disrupting Chemical Exposure Induces Adverse Effects on the Population Dynamics of the Indo-Pacific Humpback Dolphin

Cetaceans play a pivotal role in maintaining the ecological equilibrium of ocean ecosystems. However, their populations are under global threat from environmental contaminants. Various high levels of endocrine-disrupting chemicals (EDCs) have been detected in cetaceans from the South China Sea, such as the Indo-Pacific humpback dolphins in the Pearl River Estuary (PRE), suggesting potential health risks, while the impacts of endocrine disruptors on the dolphin population remain unclear. This study aims to synthesize the population dynamics of the humpback dolphins in the PRE and their profiles of EDC contaminants from 2005 to 2019, investigating the potential role of EDCs in the population dynamics of humpback dolphins. Our comprehensive analysis indicates a sustained decline in the PRE humpback dolphin population, posing a significant risk of extinction. Variations in sex hormones induced by EDC exposure could potentially impact birth rates, further contributing to the population decline. Anthropogenic activities consistently emerge as the most significant stressor, ranking highest in importance. Conventional EDCs demonstrate more pronounced impacts on the population compared to emerging compounds. Among the conventional pollutants, DDTs take precedence, followed by zinc and chromium. The most impactful emerging EDCs are identified as alkylphenols. Notably, as the profile of EDCs changes, the significance of conventional pollutants may give way to emerging EDCs, presenting a continued challenge to the viability of the humpback dolphin population.

The first full-congener analysis of 209 polychlorinated biphenyls (PCBs) in the blubber of short-finned pilot whales (Globicephala macrorhynchus) stranded along the coast of Savu Island, Indonesia

Short-finned pilot whales (SFPW) are a group of cetaceans found globally in tropical and temperate seas and are commonly stranded in the group, but the reason behind their stranding is still unknown. No detailed information on the contamination status and bioaccumulation of halogenated organic compounds, including polychlorinated biphenyls (PCBs), in the SFPW from Indonesian waters has been reported. Therefore, we analyzed all 209 PCB congeners in the blubber of 20 SFPW specimens stranded along the coast of Savu Island, East Nusa Tenggara, Indonesia, in October 2012 to explain the status of contamination, congener profiles, potential risk of PCBs to cetaceans, and the determination of unintentionally produced PCBs (u-PCBs) in the blubber of SFPW. Concentrations of Σ209PCBs, Σ7in-PCBs, Σ12dl-PCBs, and Σ21u-PCBs were between 48 and 490 (mean:240 ± 140), 22-230 (110 ± 60), 2.6-38 (17 ± 10), and 1.0-13 (6.3 ± 3.7) ng g^-1 lipid weight (lw), respectively. Congener-specific profiles of PCBs among sex and estimated age groups were observed; relatively high proportions of tri-to penta-CBs in juveniles and highly chlorinated recalcitrant congeners in structure-activity groups (SAGs) in sub-adult females were noted. The estimated toxic equivalency (TEQs) value for dl-PCBs ranged from 2.2 to 60 TEQ_WHO pg/g lw, with juveniles containing high TEQ values than sub-adults and adults. Although the TEQs and concentrations of PCBs in SFPW stranded along Indonesian coasts were lower than those reported for similar whale species from other North Pacific regions, further research is needed to assess the long-term impact of halogenated organic pollutants on their survival and health.