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| DONNA RESERVOIR AND CANAL SYSTEM | Donna, Texas | |
| Hidalgo, County |
Site Location:
The Donna Reservoir is a drinking water and irrigation storage reservoir
located southwest of the City of Donna, Texas, in south-central Hidalgo
County. The system consists of two mechanical (diesel) pumping
facilities, a 11.3 kilometer-long main canal, a 400 acre reservoir
(Donna Reservoir), and 168 miles of lateral canals and pipelines. The
site consists of contaminated sediments within a five mile stretch in
the Donna Canal and Reservoir System.
Site History:
The Donna Reservoir and Canal System (DRCS) site is located in Hidalgo
County in southern Texas just north of the Rio Grande River. The site
includes the Donna Reservoir, the Donna Main Canal (aka First Main Lift
Canal), the West and East Main Canals which extend north from the
reservoir, and a series of interconnecting canals. Total Maximum Daily
Load (TMDL) study data and 2001 Site Inspection samples show that
polychlorinated biphenyl (PCB) concentrations routinely exceed
background levels and state water quality standards in surface water
sediments and health-based benchmarks in fish. The City of Donna has a
drinking water intake located within the area of observed sediment
contamination.
Site Contamination/Contaminants:
The Texas Commission on Environmental Quality (TCEQ) conducted sampling
of the Donna Reservoir and canal system from April 9, 2001 through April
13, 2001 to document the presence or release of PCBs from soil, surface
water or suspended sediments in the reservoir and canal . The
contaminated sediment source extends approximately 5.75 miles and
includes the Donna Main Canal (aka First Main Lift Canal) from the exit
of the siphon on the north side of the Arroyo Colorado through the Donna
Reservoir, and into the West and East Main Canals to the intake for the
City of Donna. The hazardous substance associated with this source is
polychlorinated biphenyl (PCB) Arochlor-1254.
Potential Impacts on Surrounding Community/Environment:
There is a risk to individuals eating fish contaminated with PCBs. PCBs
are a human carcinogen. Previous sampling by the Texas Department of
Parks and Wildlife has documented the presence of PCBs in fish tissue in
the Donna Canal Reservoir System. A fishing ban for PCBs is in place
for this segment of the watershed. This ban prohibits all persons from
catching any fish from these waters. Despite the ban, residents are
continuing to consume fish within this system. In addition, surface
water intakes for the City of Donna lie within the area of PCB
contaminated sediments. At this time water samples collected from the
intakes have not contained concentrations of PCBs; however, the
potential for future contamination exists.
Response Activities (to date):
The Texas Department of Health issued an aquatic life closure for the
reservoir and main canal effective June 24, 1993. The closure, which is
still in effect, prohibits the taking of all species of aquatic life
from the canal and reservoir.
[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may change as additional information is gathered on the sources and extent of contamination. See 56 FR 5600, February 11, 1991, or subsequent FR notices.]
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.