Nueces Bay: A TMDL Project for Zinc

Counties: Nueces, San Patricio
Parameter: Zinc in oyster tissue
Basins: Bays and Estuaries, San Antonio–Nueces Coastal, Nueces River, Nueces–
Rio Grande Coastal
Segment: 2482
- Project Overview

- Background and Goals
- Public Participation
- Adopted TMDL
- Implementation Plan
- For More Information
Background and Goals
Nueces Bay is a shallow, secondary bay that receives freshwater from the Nueces River and exchanges saline water with Corpus Christi Bay. Economic activities in and around the bay include petrochemical refining and production, agriculture, manufacturing, recreation, maritime commerce, and tourism. Ecologically, Nueces Bay provides a home for many plants and animals, and plays a role in water purification and storm protection.
Harvesting of oysters and other edible shellfish from the bay is currently restricted because concentrations of zinc in oyster tissue pose a risk to consumers. The TCEQ’s Total Maximum Daily Load (TMDL) Program is directing a project to reduce zinc concentrations to levels that make it safe to harvest and eat oysters from the bay.
Public Participation
The TMDL Program is working with the existing forum of the Coastal Bend Bays and Estuaries Program (CBBEP)
to involve area stakeholders in the TMDL project.
Adopted TMDL
The commission adopted this TMDL on November 1, 2006. It was approved by the EPA on December 15, 2006, and is part of the state's Water Quality Management Plan.
- One Total Maximum Daily Load for Zinc in Oyster Tissue,
Nueces Bay, Segment 2482 - Response to Public Comment on the TMDL

Updates to TMDLs
From time to time, it is necessary to revise TMDLs to account for changing conditions in the watershed, such as new or amended permits, or urban growth, or to correct oversights in the original TMDL report. Revisions to the load allocations in TMDLs are made via the state’s WQMP, which is updated quarterly.
The WQMP provides projected effluent limits for use in planning and permitting activities under the Texas Pollutant Discharge Elimination System (TPDES). The TCEQ reviews all applications for new and amended permits for conformance with applicable portions of the WQMP, including adopted TMDLs.
Revisions to the TMDL are documented in the approved WQMP updates listed below.
- July 2012,
Appendix III, page 14 - April 2010,
Apendix II, pages 16-17
Learn more about WQMP updates and about opportunities to comment on revisions to them.
Implementation Plan
The commission approved the I-Plan on October 24, 2007. Sampling is continuing to ensure that zinc concentrations are attenuating.
- Implementation Plan for One Total Maximum Daily Load for Zinc in Oyster Tissue,
Nueces Bay, Segment 2482 - Response to Public Comment
on the I-Plan
Reports
- Year 5 Report of Implementation Effectiveness Monitoring,
2011 - Port Industries of Corpus Christi Meeting Presentation,
January 19, 2006 - Quantitative Risk Characterization,
2005
A report by the Texas Department of State Health Services (formerly the Department of Health) evaluating the risk to consumers from eating shellfish caught in Nueces Bay. - Quantitative Risk Characterization, 2003
For More Information
Please send an e-mail to tmdl@tceq.texas.gov, and reference the Nueces Bay project in the subject line. Or call us at 512-239-6682.



