Lake Worth: A TMDL Project for PCBs in Fish Tissue
Photograph courtesy of the
Fort Worth Water Department
Parameter: polychlorinated biphenyls (PCBs) in fish tissue
River Basin: Trinity
Segment: 0807, 0808
- Project Overview (PDF)
- Background and Goals
- Total Maximum Daily Load
- Implementation Plan
- For More Information
Background and Goals
Lake Worth (Segment 0807) is a 3,558-acre impoundment of the West Fork Trinity River located in northwest Tarrant County. The lake has a conservation capacity of approximately 37,000 acre-feet, and drains a 2,064 square-mile watershed. Water quality testing found that fish in Lake Worth (Segment 0807) are contaminated with polychlorinated biphenyls (PCBs), resulting in an advisory to the public in 2002 to limit their consumption of fish caught in the lake.
The goal of this project is to reduce PCBs to levels that will make it safe to eat fish from the lake. The goal of a TMDL is to restore the full use of a water body that has limited quality in relation to one or more of its uses. The TMDL defines an environmental target by determining the extent to which a certain pollutant must be reduced in order to attain and maintain the affected use. Based on this environmental target, the state develops an implementation plan to mitigate anthropogenic sources of pollution within the watershed and restore full use of the water body.
The TMDL I-Plan relies heavily on cleanup efforts at Air Force Plant No. 4 (AFP4), located on the south side of the lake. AFP4 is undergoing cleanup under the federal Resource Conservation and Recovery Act (RCRA) program. Also under the I-Plan, fish tissue in Lake Worth is sampled periodically to monitor the effectiveness of cleanup efforts.
Since PCB concentrations in fish tissue have stabilized and show a slow decline from levels in 2005. The DSHS conducted the first fish tissue monitoring under the I-Plan in October 2008. Based on that monitoring data, the DSHS extended the advisory to include Segment 0808. However, the new advisory limits the warning to three fish species rather than to all species.
If concentrations of PCBs in fish tissue fail to decline after two consecutive monitoring events, the TCEQ will revise the I-Plan to include alternative or additional measures.
Total Maximum Daily Load
The commission adopted this TMDL on August 10, 2005. The EPA approved it on October 13, 2005, at which time it became part of the state's Water Quality Management Plan.
- One Total Maximum Daily Load for Polychlorinated Biphenyls (PCBs) in Fish Tissue in Lake Worth, Tarrant County (PDF)
- Response to Public Comment on the TMDL, June 2005 (PDF)
Proposed Amendment to the TMDL
From time to time, it is necessary to revise TMDLs to account for changing conditions in the watershed. Revisions to the load allocations in TMDLs are made via the state’s Water Quality Management Plan (WQMP), which is updated quarterly. Revisions are made to TMDLs in one of two ways:
- Updates are made to account for changing conditions in the watershed, such as new or revised wasteload allocations, permits that have been canceled or have expired, or changed facility names.
- Addenda are created to add load allocations for assessment units that are impaired by the same pollutant or condition, within the same watershed as in the original TMDL report.
The TCEQ proposes to amend these TMDLs in its July 2014 draft Update to the Texas Water Quality Management Plan . The proposed amendment is in Appendix V, page 19, and is pending approval by the EPA.
The Commission approved this I-Plan on August 23, 2006. The I-Plan is part of the state's Water Quality Management Plan.
- Implementation Plan for One Total Maximum Daily Load for Polychlorinated Biphenyls (PCBs) in Fish Tissue in Lake Worth, Segment 0807 (PDF)
- Response to Public Comment on the Implementation Plan, July 2006 (PDF)
For More Information
For further information regarding the TMDLs or I-Plan, please e-mail us at firstname.lastname@example.org and mention the Lake Worth PCB project in the subject line. Or call us at 512-239-6682.