Proceedings of the 11 th International Coral Reef Symposium, Ft. Lauderdale, Florida, 7-11 July 2008 Session 23 Contaminants in Fishes from Johnston Atoll L. Kerr Lobel 1 and P.S. Lobel 1 1) Boston University, Department of Biology, 5 Cummington St., Boston, MA, 02215 USA Abstract. This study examined the distribution of military-industrial contaminants accumulating in coral reef fishes in the lagoon of Johnston Atoll, Pacific Ocean. This atoll was a major military base involved in nuclear and chemical weapons as well as being a depot, transient airfield and harbor since the 1930's. The base was closed and abandoned in 2003. Fishes of different trophic levels were sampled from locations throughout the atoll. Contaminants of concern included radionuclides, heavy metals (antimony, arsenic, barium, cadmium, chromium, copper, lead, mercury and zinc) and organic contaminants including; polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), herbicides, dioxins and furans (PCDD/PCDFs). The northwest section of Johnston Island, the largest island in the atoll, was the area with the highest level and variety of contaminants in fishes and sediments. This was near the site of the open burn pit and trash dump, fire training and explosives detonation areas, and the former storage site of Herbicide (Agent) Orange. Keywords: Central Pacific Ocean, PCBs, PAHs, dioxin, Agent Orange, weapons grade plutonium Introduction Johnston is a remote Central Pacific Atoll. The nearest landfall is French Frigate Shoals, 804 km (500 miles) north. The atoll is about 1,287 km (800 miles) southwest of Honolulu, Hawaii and 1,440 km (900 miles) north of the Line Islands of Kiribati. Johnston Atoll (JA) came under military control in 1934 and remained so until 2003. Its use varied during those years but included extensive use as a refueling site, atmospheric nuclear testing, master LORAN station for the Pacific, storage site for unused herbicide orange (agent orange) and chemical weapons, and the incineration of chemical weapons in the Johnston Atoll Chemical Ammunition Disposal System (JACADS) (Lobel and Lobel 2008). Many of the activities mentioned above, as well as infrastructure needed to support a military and civilian workforce of up to 2000 people, contributed to soil and sediment contamination within the atoll (Lobel and Kerr 2002). Polycyclic aromatic hydrocarbon, petroleum hydrocarbon and metal contamination was associated with refuse burning, fire training operations and fuel storage. Organochlorine contamination due to leakage from discarded electrical equipment, transformers, polychlorinated biphenyl (PCB) contaminated fuel and herbicide orange (HO) were the main contaminants of potential concern (COPC) due to accumulation in top predators and potential toxicity. HO contains two active ingredients, the n- butyl ester of 2,4- dichlorophenoxyacetic acid (2,4- D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), as well as the contaminant 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD). Polychlorinated biphenyls were found mainly in two areas of the lagoon, the west end of Sand Island and in the Navy Pier (tank 49 lagoon) area on Johnston Island (JI), the main island within the atoll. Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF) contamination in soil and nearshore sediments of the northwest corner of JI was caused by leaking storage drums containing HO (Lobel and Kerr 2002). Of the four aborted nuclear tests that occurred on JI, two would have contributed to the dispersal of radionuclides into the lagoon. Most of the debris and residual plutonium from the STARFISH event, aborted at 30,000 feet, landed in the water surrounding JI and on adjacent Sand Island. The BLUEGILL PRIME event scattered radioactive material primarily downwind of the launch emplacement. The single residual contaminant was Weapons Grade Plutonium (WGP), which consists of five isotopes of plutonium (238, 239, 240, 241, and 242) and americium-241. This review summarizes contaminant data in aquatic biota from multiple studies/sampling events sponsored by different agencies. Management responsibility for JA is shared among several agencies including the US Air Force, US Army, US Coast Guard, US Fish and Wildlife Service and the Defense Threat Reduction Agency thus, an integrated approach to ecosystem management including the need for long-term monitoring and potential cleanup is necessary. 1121