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May 12 2009, 12:25 PM EDT (current) HydroGeek
May 12 2009, 12:22 PM EDT HydroGeek 1 word added, 1 word deleted

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What is CARD?
  • The Coalition for Action on Remediation of Dioxane (CARD) is a partnership of local governments and citizens that develops policies and strategies to address the problems caused by 1,4-dioxane released by Pall/Gelman (Pall Life Sciences or PLS).

What is 1,4-dioxane?
  • 1,4-dioxane is an industrial solvent.
  • Acute (short-term) inhalation exposure to high levels of 1,4-dioxane has caused vertigo, drowsiness, headache, anorexia and irritation of the eyes, nose, throat, and lungs in humans. It may also irritate the skin. Damage to the liver and kidneys has been observed in rats chronically (long-term) exposed in their drinking water. In three epidemiological studies on workers exposed to 1,4-dioxane, the observed number of cancer cases did not differ from the expected cancer deaths. Tumors have been observed in orally exposed animals. EPA has classified 1,4-dioxane as a Group B2, probable human carcinogen. (EPA Technology Transfer Network)
  • RLC - [Please insert toxicology concerns and any updates]
  • EPA has 1,4 Dioxane on its contaminant candidate list 3 (CCL3) - their list of compounds of concern for drinking water. [cite]
  • Important Note - this is 1,4-dioxane and NOT DIOXIN, which is a worse carcinogen but one that does not migrate with water nearly as readily as 1,4-dioxane.
  • 1,4-dioxane is fully miscible in water, thus will go whereever water goes.
  • Most dioxane contamination sites result from spills of other industrial solvents that contain a small percentage of 1,4-dioxane as a stabilizer. The Pall/Gelman contamination resulted from Gelman's use of 100% dioxane in the manufacture of its filters.

Where did it come from?
  • From 1966 to 1986, Gelman Sciences used a reported 800,000 lbs of 1,4-dioxane in the manufacture of its filters.
  • Dioxane and other industrial chemicals were disposed of in a number of ways on the property including disposal in unlined lagoons, spray irrigation, and deep well injection. There was also some venting of contiminated wastewater to nearby surface waters.
  • The contamination has migrated in groundwater aquifers several directions off of the site. [plume map]
  • In 1989-90, a company analysis estimated that there were 64,000 lbs in the groundwater and that it would cost $44 million to clean it up to the 3 ppb standard in effect at that time. Since then, the company has removed over 80,000 lbs of 1,4-dioxane.
  • In 2009, there are still areas with over 20,000 ppb of 1,4-dioxane in the groundwater.
  • The contaminated groundwater plumes are over 3 miles long and 1 mile wide.

Where is the Contamination in 2009?

  • Pall/Gelman Property 2009 plumes - PLS propertycloseup 2009 Plume Map
    • High concentrations of 1,4-dioxane contamination still exist in the soils, marshy area, and groundwater on the company's property on South Wagner Road.
    • Contamination still eminates from the site in several directions - southwest, west, northwest, north, northeast, and east.
    • The largest known plume is in the deepest aquifer and is heading generally east through Ann Arbor.
  • Scio Township2009 plumes - Scio Twp props with wells 2009 Plume Map + Scio Twp Props with Wells
    • Dozens of township properties' wells around the Gelman site were contaminated with dioxane and had to be shut down and the properties hooked up to the City of Ann Arbor's municipal water and sewer system.
    • For properties east of Wagner Road, the properties also were required to annexed to the City, thus reducing Scio Township's tax base and increasing the municipal property tax for the annexed properties.
    • Hundreds of Scio Township with wells and no access to city water lie north of the Pall/Gelman site.
  • Ann Arbor Township 2009 plumes - Ann Arbor Twp boundariesPlume Map + Ann Arbor Twp "islands"
    • There are township islands within the city boundary that have been affected.
    • Additional properties may be affected if the dioxane plumes are allowed to spread.
  • City of Ann Arbor 2009 plumes - Ann ArborPlume Map - Ann Arbor with NW Supply Well
    • Contamination has moved with the groundwater from the Pall/Gelman site to the northeast and east within the city limits.
    • The northeastly Evergreen Plume [map] has been remediated since 1993 and refers to the original subdivision affected along Dexter Road. 2009 D2 - Evergreen plume
      • Most of these homes were on wells but are now connected to city water because the wells were contaminated with dioxane.
      • There is an extraction system in place and the company (Pall Life Sciences) is required to capture the plume at 85 ppb - the current MDEQ residental groundwater cleanup standard.
      • Status: It is doubtful that PLS is capturing the plume at Evergreen as required by the Consent Judgement. This is important for two reasons. (1) the company is required to capture the leading edge of the Evergreen plume and (2) significant fines were placed on hold but may be back in play if PLS is out of compliance.
      • PLS had argued that they are extracting contamination from another source (the E Plume) and are not out of compliance. They have installed additional wells to attempt to demonstrate this to the MDEQ.
      • Recently, PLS reversed its position and concluded that the D2 aquifer at Evergreen and the deeper E aquifer are parts of the same aquifer.
      • PLS uses this to argue for expanding the 2800 ppb Prohibition Zone [pink outline] to include the Evergreen contaminaton and eliminate the need to clean up Evergreen.
    • The deeper E plume is the largest plume and has moved east from the Gelman site under the west side of Ann Arbor. 2009 Unit E 3D plume - PZ
      • Unlike the Evergreen plume, the court has allowed PLS to let 2800 ppb of 1,4 Dioxane to migrate east of Maple Road.
      • The 2800 ppb number is based on the Groundwater-Surface water Interface or GSI standard - or the amount of 1,4-dioxane in groundwater that MDEQ believes is allowable to "vent" to surface water where the water is not used for human consumption downstream.
      • The E unit contamination has to be cleaned up to 85 ppb west of Wagner Road, but just east of Wagner Road, the contamination only has to be cleaned up to 2800 ppb.
      • PLS predicts that the E plume of dioxane will vent to the Huron River somewhere near Argo Dam.
      • The Court ordered a prohibition zone [red outline] for the E aquifer contamination east of Wagner Road that severely limits the use of groundwater by property owners.
      • PLS had planned to pump 200 gpm from Maple Village to remediate the E plume, but they are currently pumping only about 50 gpm and are having problems maintaining that rate because of plugging of the well were the treated effluent is being re-injected back into the aquifer.
      • Because of these apparent re-injection problems, the company now proposes to drastically reduce the cleanup effort at Evergreen, build another pipeline from Maple to connect with the Evergreen pipeline, and pump the Maple Road purgewater back to PLS's Wagner Road plant for discharge to the Honey Creek tributary.
Outstanding questions include:

  • What changes are in PLS's current proposal?
    • PLS'a current proposal would change the cleanup criteria for the Evergreen plume from 85 ppb to groundwater-surface water interface standard of 2800 ppb.
    • It also would change the core cleanup criteria west of Wagner Road from 85 ppb to an arbitrary 500 ppb.
    • PLS proposes to reduce their total purge rates from 1300 gpm to 800 gpm.
  • What will happen to the dioxane that PLS no longer has to clean up?
    • Current modeling is inadequate to predict where the dioxane will end up.
    • When purging stops, the groundwater flow patterns will return to the natural state, which judging from where dioxane flowed originally, may contaminate additional water supplies.
    • The core dioxane may again head southwest, northwest, north, northeast at unknown rates.
    • The Western Plume may again increase to unacceptable levels and threaten residential wells north of I-94.
    • The Evergreen plume may head towards Barton Pond where Ann Arbor gets 80% of its water.
  • Where will the plume through the city go and where will it vent to the River?
    • PLS is required to perform a downgradient investigation and has submitted this report to MDEQ. MDEQ responded with comments.
    • Some of the dioxane is deep enough that it may flow under the river.
    • Some of the dioxane may shift and flow along the river threatening some wells outside the prohibition zone further downstream.
    • Some of the dioxane may vent the Allen Creek drain before it gets to the river as it gets to neighborhoods with historically active artesian conditions.
    • No investigation has occurred to measure 1,4-dioxane in the stormwater system to see if any of the groundwater is infiltrating into the stormwater or sanitary systems.
  • How do we know that the contamination crossing Maple Road will remain under the court ordered 2800 ppb GSI standard?
    • MDEQ has required PLS to install monitoring wells in Veterans Park across from the Maple Village Shopping Center. Three wells were to be installed - two were and one could not be installed because the well rig hit boulders. PLS and MDEQ disagree about the installation of the third well - the northernmost well.
    • PLS has installed extraction and re-injection wells at Maple Village. Water is extracted from two wells - piped north to a portable treatment system on the former Milk Depot property on Dexter Road where it is treated with hydrogen peroxide and ozone to partially destroy the 1,4 dioxane. The effluent is then piped back to Maple Village where it is re-injected back into the contaminated aquifer. Re-injection of partially treated water can cause the well screens to become plugged, thus the PLS Maple Road system is often shut down because PLS cannot re-inject at the necessary rate.

Who is responsible for cleaning up the contamination?
  • Pall Corporation acquired Gelman Sciences in 1997 and thereby assumed responsibly for the cleanup.