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CONDITION OF ESTUARIES AND BAYS OF HAWAII FOR 2002: A STATISTICAL SUMMARY
Citation:
NELSON, W. G., R. BROCK, H. LEE, II, J. O. LAMBERSON, AND F. A. COLE. CONDITION OF ESTUARIES AND BAYS OF HAWAII FOR 2002: A STATISTICAL SUMMARY. U.S. Environmental Protection Agency, Washington, DC, EPA/620/R-07/001 (NTIS PB2007-107910), 2007.
Impact/Purpose:
To provide a baseline estimate of condition of coastal resources that will allow determination of trends
Description:
The National Coastal Assessment (NCA) of US EPA conducted the first probabilistic assessment of the condition of estuarine resources of the main islands of Hawaii in 2002. The study provided condition estimates for both the estuaries and bays of the Hawaiian Island chain, as well as for a more focused assessment of condition of the urbanized estuaries within the city of Honolulu. The assessment evaluated condition of both hard (e.g. coral reefs) and sedimentary bottom habitats, introducing the use of underwater visual surveys of hard substrates and fish communities to the NCA program. Hard substrates were encountered at 48% of sites sampled, although sufficient sediment for chemical contaminant analyses could be collected at 74 of the 79 study sites. Among pollutant exposure indicators, less than 9% of the area of both the Hawaii estuaries and bays and the Oahu urbanized estuaries had bottom water dissolved oxygen concentrations ¿ 5 mg/L. Chromium and mercury were the only metals exceeding the Effects Range Median concentration (ERM), and did so in ¿1% of the area of Hawaii estuaries and bays and in ¿5% of area in the Oahu urbanized estuaries. There were no exceedances of the ERM for any organic compound analyzed at any station. Tests with the amphipod Ampelisca abdita found no instances of elevated sediment toxicity in Oahu urbanized estuaries, but showed increased mortality above controls in 10% of the area of Hawaii estuaries and bays. Approximately 4% of the area of Hawaii estuaries and bays and 13% of Oahu urbanized areas exceeded the Hawaii criterion for enterococci, with the caveat that the state enterococci criterion requires multiple samples, and the EMAP samples are single events. Among the soft sediment fauna, 57 % of the polychaete taxa are classified as nonindigenous in origin, suggesting fairly widespread introduction of nonindigenous benthic taxa. The study results constitute a baseline estimate of condition of coastal resources that will allow determination of trends in condition through future assessment.