SEDIMENT QUALITY TRIAD ASSESSMENT SURVEY OF THE GALVESTON BAY, TEXAS SYSTEM

To characterize the quality of sediments at key sites in the Galveston Bay Estuary, sediment samples were collected concurrently for chemica l and physical analyses, toxicity testing and an assessment of benthic community structure. Significant toxicity, as determined by the sea u rchin (Arbacia punctulata) pore water embryological development assay, was observed at 12 of the 24 sites investigated in this study. No tox icity was observed at any of the sites with the amphipod (Grandidierel la japonica) solid-phase test. There were a number of sites with eleva ted levels of trace metals and petroleum hydrocarbons. The chemistry, toxicity and benthic data were ranked by station and a scaled rank sum was calculated to facilitate comparisons among the stations. Five sit es exhibited strong evidence of contaminant-induced degradation, while 15 stations showed no evidence of contaminant-induced degradation. At eight additional sites the sediment quality triad (SQT) data indicate d that unmeasured chemicals or conditions were stressing the system. C ontaminant impacts could be reduced or eliminated by alternative regul atory and management practices, including the restriction of produced water discharges into coastal estuaries and the use of dredge material disposal practices that minimize the reintroduction of sediment-assoc iated contaminants to the bays.