Persistent Organic Pollutants and Mercury in Genetically Identified Inner Estuary Bottlenose Dolphin (Tursiops truncatus) Residents of the Guayaquil Gulf, Ecuador: Ecotoxicological Science in Support of Pollutant Management and Cetacean Conservation

Frontiers in Marine Science

Windsor Aguirre¹  Patricia A. Fair²  Juan José Alava³  Pedro J. Jiménez³  George Biedenbach⁴  Gregory D. Bossart⁴  Ana Tirapé⁶  Paola Calle⁶  Omar Alvarado Cadena⁶  Gustavo A. Domínguez⁶  Keith Maruya⁹  Wenjian Lao⁹ 

[1] Department of Biological Sciences, DePaul University, Chicago, IL, United States;Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, United States;Fundación Ecuatoriana para el Estudio de Mamíferos Marinos (FEMM), Guayaquil, Ecuador;Georgia Aquarium, Atlanta, GA, United States;Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, BC, Canada;Laboratorio de Investigaciones Toxicológicas y Salud Ambiental, Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, ESPOL, ESPOL Polytechnic University, Guayaquil, Ecuador;School of Resources and Environmental Management, Simon Fraser University, Burnaby, BC, Canada;South Carolina Aquarium, Charleston, SC, United States;Southern California Coastal Water Research Project, Costa Mesa, CA, United States;

关键词: contaminants;    POPs;    organic mercury;    marine mammals;    toxicological risk assessment;    mangroves;   

DOI  :  10.3389/fmars.2020.00122

来源: DOAJ

【 摘 要 】

The bottlenose dolphin is one of the most common cetaceans found in the coastal waters, estuaries, and mangroves of Ecuador. However, its population size is gradually declining in the Gulf of Guayaquil, and anthropogenic factors including habitat degradation, uncontrolled dolphin watching, dredging activities, increasing maritime traffic, underwater noise, bycatch, and marine pollution have been implicated in their decline. Very little is known about contamination by persistent organic pollutants (POPs) and mercury in bottlenose dolphins from the Pacific coast of South America. To address this research gap, the first assessment of total mercury (THg) and POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), in free-ranging bottlenose dolphins in mangroves (El Morro Mangrove Wildlife Refuge) of the Gulf of Guayaquil, was conducted in Ecuador in 2018. Dolphin samples (i.e., skin and blubber; n = 9), were obtained using dart biopsy field methods for contaminant analysis. POP concentrations ranged from 0.56 to 13.0 mg/kg in lipid weight, while THg ranged from 1.92 to 3.63 mg/kg in dry weight. The predominant POPs were OCPs (50% of ΣPOP), followed by PCBs (46%) and PBDEs (6.0%); particularly, p,p′-DDE, the main DDT metabolite and a potent anti-androgenic, accounting for 42% of ΣPOP, ranging from 0.12 to ∼7.0 mg/kg lw, followed by PCB 153 (8.0%) and PCB 180 (5.0%). PBDE 47 accounted for 2.0% of ΣPOP. While the POP concentrations are lower than those found in dolphins from many other regions of the world, some of the THg concentrations are within the concentration range found in dolphins from the southeastern coast of the United States. The ecotoxicological risk assessment showed that some of the sampled dolphins are exposed to immunotoxic and endocrine disruption effects by POPs and mercury. The low genetic diversity of this distinctive dolphin population, likely exhibiting genetic isolation and a unique evolutionary heritage, could be lost if the population continues to decline in the face of anthropogenic threats, including chemical pollution. Our finding shows that bottlenose dolphins in coastal Ecuador are exposed to environmental contaminants and can be used as sentinel species for ecosystem health to monitor pollution in the region and to support ecotoxicological risk assessment and regional pollutant management.

【 授权许可】

Unknown