Polychlorinated Dibenzo- p -dioxins and Dibenzofurans in Houston Ship Channel Tissue and Sediment

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured in sediment, catfish, and crab tissue from 45 locations in the Houston Ship Channel in Texas in the Summer of 2002. Concentrations of individual 2378-substituted congeners ranged from 0.1 to 42,000 ng/kg dry wt, from 0.1 to 230 ng/kg wet wt, and from 0.1 to 260 ng/kg wet wt for sediment, catfish, and crab samples, respectively. OCDD concentrations in sediments were up to two orders of magnitude higher than those for the remaining congeners, but this signature was not observed in catfish and crab samples. Results from this study suggest that despite regulatory controls on discharges from pulp and paper mills, there has been little change over the last 10 years in dioxin concentrations in sediment and tissue from the Houston Ship Channel. Ongoing PCDD/PCDF inputs from urban and industrial areas along the channel as well as resuspension/desorption from contaminated sediments may provide a partial explanation for the lack of change. Simple correlation statistical and principal component analyses were undertaken.