Summary

Description

The San Bernard National Wildlife Refuge is located approximately 10 miles south of a major industrial complex at Freeport, Texas, and is connected to this complex by the Gulf Intracoastal Waterway GIWW, a canal used primarily for barge traffic. The potential for spills of oil and chemicals is high in this waterway, as is contamination from urban runoff from Freeport, Texas, and waste discharges from the industrial complex. Data from this survey does not indicate any contamination by organochlorine or organophosphate pesticides is occurring at this time on the San Bernard National Wildlife Refuge. Two heavy metals, cadmium and chromium, had elevated residue levels in the sediment and oyster samples collected from Cow Trap Lake, the estuarine portion of the refuge. The presence of these two metals may indicate some contamination from the Freeport, Texas area is being transported south along the GIWW. These metals were not at high enough levels to evoke action at this time, but future monitoring for heavy metals is recommended to detect if a trend toward increased contamination is evident. Petroleum hydrocarbons were also detected at elevated levels in sediment and oyster samples collected in Cow Trap Lake. These residues probably reflect the petroleum spills that occur in the GIWW as well as the minor oiling that occurs from small outboard motors on the numerous fishing boats that utilize the GIWW and Cow Trap Lake. The freshwater portion of the refuge is apparently free from contamination. The small reserve pit at the gas well on the Big Boggy unit is contaminated with lead and petroleum hydrocarbons. The lead does not appear to be in a bioavailable form presently. This pit should, however, be drained, dried, and plowed to a depth of eight inches in order to bioremediate the hydrocarbons. This would also make the lead even less available to natural resources.