Development of a Dioxin TMDL for the Houston Ship Channel in Texas
Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxin) are extremely persistent in the environment, and can affect human health at low concentrations for many years. As a result of dioxin found in fish and crab tissue, a seafood consumption advisory was issued by the Texas Department of Health in September 1990 for the upper portion of Galveston Bay and the Houston Ship Channel System (HSC) in Texas. As a result of the advisory, the HSC system was placed on the 303(d) list and a Total Maximum Daily Load (TMDL) study was initiated. This paper presents the current results of the most comprehensive, aquatic multimedia dioxin study performed in the US and summarizes loads from significant sources such as municipal and industrial WWTPs, nonpoint source, and atmospheric deposition.