TCE and PCE Remediation and the LPRV


ARCHIVE ACCESS

Use the archive below to learn more about TCE contamination and the Lower Portneuf River Valley Aquifer. Select a topic from the list below and then CLICK to access.

GENERAL INFORMATION

What is TCE?
What is PCE?
Is My Water Safe to Drink?

PLUME ACTION PROPOSAL

Summary
Overview
Fact Sheet 1
Fact Sheet 2
Appendix 1
Appendix 2
Appendix 3
References
Download Full Report (MS Word)

OZONATION PILOT TEST

General Information
Objectives
Tasks
Committee
Download Full Report (MS Word)

FIGURES

Aeration Tower
Affected Pocatello Wells
Aquifer Schematic
Annual Average TCE: 1993
Annual Average TCE: 1998
Annual Average TCE Graph
Annual Average TCE Table
Historic PCE: Wells C1-C5
TCE Plume Location
TCE in Upper Gradient Wells
Ozone Pilot Test - View 1
Ozone Pilot Test - View 2
Ozone Pilot Test - View 3
Ozone Pilot Test - View 4
Ozone Pilot Test - View 5
Ozone Pilot Test - View 6
Ozone Pilot Test - View 7
Ozone Pilot Test - View 8
Well 44 Capture Effect

WELL WATER DATA

Access historical TCE/PCE concentration information for specific municipal wells using the menu below. Select a well number, then hit the GO GET DATA button to retreive the data.

The TCE problem, and its costly solutions, typify the logic behind the adage that "it is always cheaper to prevent groundwater pollution than to clean it up after it has occurred."

Some archive entries are
in MS Word format.

ABOUT TCE, PCE & THE LPRV AQUIFERPocatello's Pilot Test Ozonator

Perhaps the most well-known example of groundwater contamination in the lower Portneuf Valley is the trichloroethylene (TCE) in the southern valley and in the vicinity of the old County landfill.

A similar chlorinated solvent, perchloroethylene (PCE or PERC), has been detected in Chubbuck's Well No. 4. Water from this well is being treated successfully to remove high concentrations of PCE.

Both TCE and PCE originate from disposal on the land surface, and find their way to the water table where they are then carried by the movement of groundwater.

Due to the rapid rate of groundwater flow in the southern valley aquifer (up to 50 feet per day), the TCE plume at one time was advancing and affecting water quality in downstream wells at the rate of a mile per year.

Several wells have been closed because their concentrations of TCE exceed safe limits; some remain closed, others have reopened.

The plume still extends the length of the southern valley.

It is for these reasons that city water managers contracted with consulting engineers to draw up plans for special wells to capture the moving TCE, remove it from the water, and return clean water to the aquifer. This plan has the advantages of curtailing the spread of TCE, protecting downstream wells from future contamination, and pumping part of the cleaned water into the water distribution system to meet current and future demand.

However, the city decided not to proceed with this costlier solution, and instead directed water managers to install Well #44 in an uncontaminated portion of the aquifer (directly across the river from the TCE plume). Though it is impossible to predict with current information, but there is a good possibility that Well #44's pumping may eventually smear the TCE plume across the width of the aquifer.

If nothing is done to stop the spread of TCE, it could be only a matter of time before the entire southern aquifer is contaminated.

Although some argue that by cleaning up the TCE at its likely source (the old landfill), the TCE plume problem will disappear and make it unnecessary to protect downstream wells, it is known that even if the TCE source can be 100% contained at the landfill, it will be decades (perhaps many) before TCE that has already leaked out of the landfill will be flushed out of the system by natural through-flow.

More than 100 gallons of liquid TCE have already passed through the aquifer, suggesting that much more remains at the source to continue contaminating the aquifer in future.

If pools of liquid TCE exist somewhere in the aquifer, it could take centuries for natural flushing to clear the aquifer of this contaminant.

This is a very safe prediction, based on examples of TCE contamination in many other aquifers.


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