Macrobenthos monitoring near the Sand Island and Barbers Point ocean outfalls, O'ahu, Hawai'i

The Sand Island and Barbers Point primary treatment plants discharge wastewaters into Ma~mala Bay through ocean outfalls located off the southern coast of O'ahu, Hawai'i, at a water depth of approximately 60 m. The macrobenthos in the vicinity of these outfalls has been monitored since 1986. Replicate grabs at multiple stations located along transects and depth contours have been collected to provide biological samples for quantitative analyses. Samples for analysis of sediment grain size and parameters of sediment organic enrichment have also been collected. Benthic conditions at sites near the outfalls have been compared with reference conditions at sites 3 to 6 km from the outfalls to assess biological changes that might be related to the wastewater discharges. The structure of mollusk, nonmollusk (all macrobenthos excluding mollusks), and crustacean assemblages has been analyzed separately.