Donna Reservoir and Canal System “Superfund” Site

Donna, Hidalgo County, Texas

Health Assessment Team

The assessment team conducts Public Health Assessments on hazardous waste

sites following proposal to the Environmental Protection Agency’s National Priorities List (Superfund)

Health Assessor, Health Educator, Community Liaison

the team will:

• Identify human populations at risk

• Reduce and prevent adverse human health conditions from toxic environmental exposures

• Educate communities on exposure prevention and pathways

Health Assessment

The Health Assessment has 3 versions:

Technical – Reviewed by state & federal environmental agencies for their approval.

Public Comment – Reviewed by the public. Comments from the public regarding the health assessment are received by DSHS.

Final – document is finalized. Comments received are answered and incorporated into the document. Public comments can alter the final outcome.

Health Assessment Team

Map Key:      Proposed: 3        Final: 46        Deleted: 10

Background

1993 EPA was investigating neural tube defect cluster in the Valley area.

A family gave EPA a tissue (fillet) sample from a fish supposedly caught in the Donna Canal.

The fish had a concentration of 399 ppm PCB. The highest ever recorded in a fish.

Investigations of reservoir & canal began as result.

Polychlorinated Biphenylstructure

(209 possible combinations)

PCBs

Withstand high heat – transformers and capacitors

Very stable - therefore persistent for long periods of time in the environment

98% of US Manufacture by Monsantotradename – Aroclor

Aroclor 1254 (12 C atoms, 54% Cl) generally the more chlorinated, the more toxic

Other countries also produced PCBs.

1978 ban - US production & importation

Potential Health Effects

• The most commonly observed long term health effects in people exposed to high levels of PCB’s are skin conditions such as acne and

rashes

• Long term exposure may cause liver damage

• A pregnant woman who eats food contaminated with high levels of PCB’s can pass the chemicals to her unborn child and may cause the child to have slower mental development and difficulty learning

• Young children may also experience developmental health effects from eating contaminated fish

Lipophilic – loves fatty tissue

Nature and Extent of Contamination

DSHS fish ban in place since February 1994

• area covered by the ban includes the irrigation canal beginning at the Rio Grande and up to and

including the reservoir

• fish contain PCB (polychlorinated biphenyl)

• possession of fish from the canal and reservoir can result in a fine up to $500

DSHS Fish Ban

Findings

PCB (Aroclor 1254) found in fish tissue & suspended sediments

Fish (range: BDL – 20.15 ppm mean: 1.516 ppm)FDA limit: 2 ppm EPA limit: 1.4 ppm – state should consider action

Suspended sediments (range: nd – 0.130 ppm)

No public health hazard - exposure pathway eliminated:

surface water, drinking water, and bottom sediment – no PCBs

air – no samples collected (low volatility high affinity for soil)

No apparent public health hazard: suspended sediment - not significant exposure pathway

(low probability of regular exposure)

Public health hazard – ingestion of fish

Exposure Pathways

Actions Planned

EPA will continue removing fish EPA seeking contaminant source

DSHS Community Involvement DSHS Health Education

Health Education

Example of pamphlet

Door hanger

Attend local school functions

Visit businesses

(sporting goods, jiffy marts, etc.)

Community Involvement – public meetings

Health Assessment Team Contacts

Health Assessment and Toxicology GroupEnvironmental & Injury Epidemiology & Toxicology Branch

(800) 588-1248www.dshs.state.tx.us/epitox

Tom EllerbeeEnvironmental

Specialist

Tina WalkerHealth Educator

Nancy IngramCommunity Liaison