Shrnutí

Popis

Citizens, and State and Federal regulatory agencies, are concerned about chemical contamination of coastal ecosystems. In response to citizen interest in Perdido Bay, the U.S. Environmental Protection Agency EPA provided funding to the Fish and Wildlife Service Service to produce a status report about existing chemical conditions. In addition to a review of existing reports and data, the Service conducted field work that included water, sediment and biotic chemical analyses, a tenday toxicity test, a fish health assessment, and an evaluation of dioxin compounds. A review of the most important chemical data bases for the Perdido Bay ecosystem reveals that Perdido Bay is generally free of toxic compounds. However, sediments in some discrete areas are contaminated. Contamination has been identified in Elevenmile Creek, Saufley Field Ditch, and Bayou Marcus. Detectable chemical contaminants have also been identified at one marina and in some locations within Perdido Bay. Contaminants of concern at some sediment sites include: mercury, silver and dioxin compounds. Results of the field toxicity tests suggest that the water and sediments tested are not acutely toxic, but based on reduced feeding activity of the test organisms, there appears to be reduced water quality at some locations. Samples of some species of fishes in the Perdido River contain undesirable concentrations of mercury. In the past, fish from Elevenmile Creek have contained quantities of dioxin. Fish collected from Elevenmile Creek, and analyzed within the last three years, contained minimal or nondetectable concentrations of dioxin compounds. These analytical data have resulted in the removal of the consumption advisory for fish taken from the Creek. Significant concentrations of dioxin have been found in two turtles collected from the Creek. Recommendations for future research and for estuarine management include additional mercury and dioxin field work; evaluation of any environmental impacts related to agricultural chemicals; assessment of the need for, and practicality of, cleanup of silvercontaminated sediments at the mouth of Saufley Field ditch; and the continuation and acceleration of environmental management programs involving stormwater control, agricultural best management practices and stateoftheart industrial and municipal effluent treatment.