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Exposure to 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) impacts multiple organ systems in developing little skate (Leucoraja erinacea).
Merson, R., T. Bock, S. Lazar, C. Rei-Mohammed, Saro Jayaraman, B. Clark, D. Champlin, AND D. Nacci. Exposure to 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) impacts multiple organ systems in developing little skate (Leucoraja erinacea). Society of Environmental Toxicology and Chemistry (SETAC) World Congress, Orlando, FL, November 06, 2002 - November 10, 2016.
This manuscript describes experimental studies that contribute to our understanding of the ecological risks associated with chronic contaminant exposures to wildlife populations. Results of these studies demonstrate the value of molecular tools to diagnose and predict effects of chemical stressors and characterize the mechanisms and costs of toxic and compensatory responses to chemical stressors by wild populations. General impacts from this contribution include improved understanding by managers and scientists of links between human activities, natural dynamics, ecological stressors and ecosystem condition.
Effects of exposure to coplanar polychlorinated biphenyls (PCBs) and other dioxin-like chemicals on developing vertebrates involve many organ systems, including the skeletal and cardiovascular systems. Apex predators, including those from the class Chondrichthyes (sharks, skates, and rays), accumulate high body burdens of PCBs through biomagnification of chemicals moving through food webs. There are no published reports of the effects of dioxin-like chemicals on the development of sharks, skates, or rays. A study was undertaken to assess developmental effects of 3, 3’, 4, 4’, 5 pentachlorobiphenyl (PCB 126) exposure in little skate, Leucoraja erinacea, a model for oviparous elasmobranchs. Skate embryos cultured outside of their egg cases were exposed to 0.02 - 20 ng/ml PCB 126 for 6 days and then grown in clean seawater for up to 29 days. Gas chromatography was used to measure PCB 126 in the exposures water and quantify its accumulation in the embryo. Digital still and video imaging was performed to assess growth, identify developmental abnormalities, and cardiovascular function. Embryos accumulated approximately 50% of PCB 126 exposure mass in the embryonic tissues and yolk sac. All embryos in the control and 0.02 ng/ml treatment survived; mortality rates were 14, 52, and 40% of embryos exposed to 0.2, 2.0, and 20.0 ng/ml, respectively. PCB 126 exposure induced yolk sac edema, deformities of the jaw, cranium, and fins, and cardiovascular system failure in skate embryos at all concentrations. This study demonstrates that little skate embryogenesis is sensitive to the toxic effects of PCB 126. Many of the developmental effects of PCB126 in skate embryos are similar to that observed in other vertebrates, however, the alteration in pectoral fin architecture is novel and may represent disruption of developmental pathways that differ between cartilaginous and bony fish appendages. The research continues to ascertain the no observable effects concentration for PCB 126 and identify sensitive developmental pathways using the little skate model.
Record Details:Record Type: DOCUMENT (PRESENTATION/SLIDE)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY
ATLANTIC ECOLOGY DIVISION
POPULATION ECOLOGY BRANCH