Benthic Ecological Condition Assessment of the Coastal Waters of Guam
The U.S. Environmental Protection Agency, Guam EPA and other collaborators conducted a pilot condition assessment of near-shore waters of Guam as part of the National Coastal Assessment (NCA) program. Results indicated that chemical contamination of sediments by heavy metals, PAHs, PCBs, and legacy pesticides did not occur at levels potentially harmful to benthic systems, apart from limited areas within the highly altered Apra Harbor. There was also no indication of contaminant-related sediment toxicity to amphipods, nor correlation of holothurian tissue contamination with sediment contaminants. Similarly, there was little indication of altered benthic community composition indicative of pollutant impacts. The NCA survey results were consistent with results from other site-specific surveys of benthic condition conducted from Guam coastal waters. Several provisional indicators (benthic substrate, fish community, holothurian tissue contamination) proved operationally feasible to incorporate into the NCA assessment approach, but until benchmark values can be determined, their use in assessment of coastal condition will be limited. The pilot NCA assessment of Guam coastal waters provides a baseline that may be particularly valuable for assessing environmental change associated with currently proposed changes to military installations and population on the island.