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You are here: Home / Water Quality / Total Maximum Daily Load Program / Houston Ship Channel and Galveston Bay: A TMDL Project for Dioxin

Houston Ship Channel and Galveston Bay: A TMDL Project for Dioxin

A project to develop TMDLs for dioxin in the Houston Ship Channel. The goal of this project is to reduce dioxin concentrations and make it safer to eat the fish.
representation of a dioxin molecule
Representation of a
Dioxin Molecule
Courtesy of the
U.S. Environmental Protection Agency

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Counties: Galveston, Harris
Parameter: Dioxin
Basins: Bays & Estuaries, San Jacinto River, Trinity-San Jacinto Coastal Basin
Segments: 0901, 1001, 1005, 1006, 1007, 2421, 2426, 2427, 2428, 2429, 2430, 2436, 2438

Background and Goals

The Houston Ship Channel System consists of 14 designated segments, which together comprise the "enclosed" portion of the Houston Ship Channel proper with its major tributaries and side bays. The dioxin TMDL project includes ten of the designated Houston Ship Channel System segments. The Houston Ship Channel has long been one of the three or four busiest ports in the United States.

The Texas Department of State Health Services (TDSHS) advises that consumers restrict their consumption of catfish and blue crab caught in the Houston Ship Channel because dioxin concentrations found in them pose a risk to consumers. Dioxin is a generic term for a suite of toxic and environmentally persistent compounds.

The goal of this TMDL project is the reduction of contaminant concentrations in fish tissue to levels that constitute an acceptable risk to consumers.

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Public Participation

The Houston-Galveston Area Council Exit the TCEQ is coordinating public participation in this project. A stakeholder group is working on this project and those for PCBs and dioxin in the Ship Channel and Upper Galveston Bay. Stakeholder group meetings are open to all.

See more about the HSC PCBs Project and the Survey of Dioxin and PCBs in Galveston Bay.

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Project Documents

The following documents are available in PDF.

Data Report

The main Data Report file contains, summarizes, and discusses the data collected to support the TMDL project. The Appendixes file has data in electronic format (Excel spreadsheets or Access databases), in folders corresponding to appendixes described in the Data Report. Most of the stream data for water, sediment, and tissue are also in the TCEQ SWQMIS database; air and runoff and effluent data are not.

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Technical Support Documents

The following files document how the modeling was done and how the load allocation was derived from model output. These documents provide much more detail than the TMDL document.

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Annual Summaries of Findings and Progress

These documents compile quarterly reports from the project. Each summarizes activities during a fiscal year (September - August). Appendices are not included with these links, but may be requested from the project manager. Summaries and information from years prior to FY2005 may also be requested.

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Presentations from Public Meetings

These slide shows were used at several public meetings during 2005 through 2007. They summarize project findings and progress, in a less dense and detailed format than the progress reports. Any target values or load allocations shown in these slides were preliminary results subject to change as analyses were refined.

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1905 Map of Galveston Bay:

This 1905 map of Galveston Bay (9.9 MB) was originally produced by the Corps of Engineers. An old paper copy was scanned to produce digital images; that was the only known copy of this map. The file posted here was made by combining two overlapping partial images, merging to a single image, adjusting color to reduce yellowed effect of original, trimmed, and reduced to 4000 x 4000 pixel density to make a smaller but readable image. Larger format (6848 x 9584 pixels) files are available in TIF and JPG format, but require additional work to merge pieces or color correct the image. Contact the TCEQ TMDL program if the original files are desired.

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For More Information

Please send an e-mail to, and reference the Houston Ship Channel Dioxin project in the subject line. Or call Jim Neece at 512-239-1524.

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