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 AQUIFER
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. |
