From: FORTUNA Steve
Sent: Tue Apr 27 16:15:35 2010
To: SEIDEL Paul
Cc: WILLIAMS Robert K; JOHNSON Keith; FORTUNA Steve
Subject: RE: City of Fairview well contamination
Importance: Normal
Attachments: FAIRVIEWcapturezone.pdf; TownsendFeatures.pdf; The City of Fairview’s Well #6 has been the most highly contaminated of the city’s eight wells. Contaminants in this well’s groundwater have included PCE, 1,1,1-TCA, TCE, and EDB. Well #6 is located south, across NE Sandy Blvd. and I-84 from Townsend Farms. It lies within about 900- to 1,500 feet south of the Townsend Farms’ former cropland, and about 1,715 feet west-southwest of the Townsend Farms Drinking Water well. Its wellhead is indeed located uphill (approximately 50- to 75 feet higher elevation) from the Townsend Farms land surface. But Well #6 is 322 feet deep, and is screened from 201- to 301 feet bgs, probably in the Troutdale Sandstone and underlying Sand and Gravel hydrologeologic units of the Troutdale Formation (as described by S.V. Hartford and W.D. McFarland in 1989). The upper 100 feet of Well #6 appears to penetrate alluvium (unconsolidated sedimentary aquifer). The Townsend Farms cropland and Drinking Water well are located on alluvium within the Columbia River flood plain. The boring log for the Townsend Farms well, and those for several monitoring wells that were recently install on the former cropland for Costco, indicate the alluvium is no thicker than about 10 feet in this area. Compacted sand that directly underlies this alluvium is probably the top of the Troutdale Sandstone unit, so surface soils at the Townsend Farms property may offer the Troutdale Formation very little protection from surface contaminants. The City of Fairview’s Drinking Water Wellhead Protection Plan indicates that the groundwater capture zone for Well #6 lies directly south of the well although it is unclear how the limits for this capture zone were defined, or what assumptions were used in developing the model. The groundwater capture zone depicted immediately east, north, and west of Well #6 appears to be suspiciously narrow. Surface elevations and surface water flow directions north of I-84 also suggest that shallow groundwater may flow toward the west-northwest just north of NE Sandy Boulevard, while surface runoff from the Townsend Farms’ former cropland may flow to the southwest, toward Well #6. A 1993 groundwater report by J.N. Bet and M.L. Rosner (Landau Associates, Inc.) (Oregon Geology, Volume 55, Number 3, pp 55-69) also indicates that, north of I-84, surface elevations reasonably approximate of the slope of the top of the Troutdale Formation. Although I’m not a hydrogeologist, I believe there is sufficient evidence to suggest that, north of I-84, shallow groundwater may flow toward the west and west-northwest. So surface runoff from the Townsend Farms property might readily infiltrate into the Troutdale Formation and be captured by City of Fairview Well #6. The Townsend Farms’ DHS-regulated Drinking Water well is 297 feet deep, and is screened from 205- to 245 feet bgs. DHS records indicate that EDB was detected in the Townsend Farms well on two occasions (in October 1994 and February 1995), and 1,1,1-TCA was detected in the well in April 1993. EDB was not detected in City of Fairview Well #6 until December 1999, and 1,1,1-TCA was not detected until April 2000. Although EDB was detected in City Well #6 five years after being detected in the Townsend Farms well, and 1,1,1-TCA was detected seven years after it was detected in the Townsend Farms well, EDB has SUBSTANTIALLY greater water-solubility than 1,1,1-TCA, and would be expected to migrate much more rapidly than 1,1,1-TCA. The Townsend Farms well is located on the eastern edge of the Townsend Farms cropland, and appears to lie just west of a slight topographic crest (a possible south-north oriented groundwater divide). The EDB and TCA detections in the Townsend Farms well might simply have been attributable to the fringe of a groundwater contamination plume that originated from on-site releases, reaching the well through radial diffusion of groundwater contaminants. It would be helpful to demonstrate that EDB is not present in shallow groundwater along the southern edge of the Townsend Farms’ former cropland. I suspect there might also be one or more old irrigation or domestic wells remaining on the southern end of the farm that could be sampled. Old, undocumented wells may also be present on parcels that Townsend Farms owns south of NE Sandy Blvd. _____________________________________________ Just wanting to close the loop on this VOC issue. So, the City of Fairview well that has had detections is upgradient across sandy boulevard and up a hill from Townsend farms (see map). The existing Townsend Farms wells has been and continues to be ND for EDB. So, if there was to be sampling it would need to be to the West in a field using a Geoprobe? I’m not clear what I should be asking the Townsends for and the rationale. Is something still needed? << File: SKMBT_C55209072915050.pdf >> _____________________________________________ Paul, As Community Water Supply wells, the state Health Division requires Townsend Farms to routinely monitor groundwater from their wells. EDB has not been detected in the Townsend Farm wells since sometime before it was detected in City of Fairview Well 6, so it seems unlikely that it would re-appear. I was more concerned with potential groundwater contamination west of the Townsend Farm wells; perhaps beneath their former berry cropland. I was speculating that It may be possible that the early EDB detections in the Townsend Farms wells could have been attributable to rapid initial radial diffusion of EDB in groundwater. Keith: It appears unlikely that further examination of Townsend Farms as a potential EDB source will be possible under the existing VCP agreement. smf ____________________________________________ HI Steve- I don’t disagree with your conclusions, although there is widespread historic ag use in the area and Townsend is one of many. Having said that, I requested both verbally and in writing that the Townsends sample their well for EDB last fall under the existing VCP agreement and they declined ( or more likely just forgot as it was not a priority to them at the time). All RI work under the existing VCP agreement is complete, we are waiting for the Townsends to compete removal actions and follow-up confirmation sampling specified before any NFA could be issued. If an NFA were to be issued, I would specifically exclude groundwater since it was not in the scope of work for the RI. Because all other RI work is substantively complete- If this groundwater work were to proceed, I think it would be cleaner and better under a totally separate agreement. _____________________________________________ Hi, Paul. Last week, Keith approved a memo I prepared summarizing potential sources of the contamination detected in the City of Fairview wells. Copies of the memo are available in my V:\ drive project files under FairviewMemoRev (text as a .docx file; text and figures as a .pdf file) In the memo, I’ve listed about ½ dozen potential sources for the PCE/TCE/1,1,1-TCA contamination detected in the city wells. I am initiating PAs on the first two of the potential PCE sources at this time. But the city wells are also contaminated with ethylene dibromide (EDB) at concentrations that have sometimes exceeded Drinking Water MCLs (and certainly exceeded residential and urban residential drinking water RBCs). It appeared very unlikely to me that the EDB source could be associated with either dry-cleaning operations or leaded gasoline: · commercial use of leaded gasoline was banned in January 1986; · EDB was probably not used in leaded gasoline after 1982 because its potential threat to drinking water was already well-understood, and a substitute had been found by then; · when in use, EDB was only added to leaded gasoline at less than about 1,000-ppm (concentrations far too low to produce DNAPL); · only transient traces of BTEX have been detected in the city wells (BTEX should have been present in the gasoline (and groundwater) at much higher concentrations than EDB). I concluded that the most likely source for EDB was agricultural operations, and proposed Townsend Farms as a potential source: · Townsend Farms grew the types of crops that used EDB most commonly (berries and root crops); · EDB had also been specified for used as a post-harvest fumigant for vegetable and berry crops; · Traces of EDB and 1,1,1-TCA had previously been detected in the Townsend Farms wells. While it’s true that there could be any number of potential sources for EDB in the local aquifer (including illegal disposals on vacant land), I concluded that Townsend Farms is the most obvious candidate at this time. Addressing potential PCE sources alone will probably do nothing ameliorate potential health-related issues for the City of Fairview drinking water. I recommended to Keith that Townsend Farms concurrently be examined as a potential source for the EDB contamination detected in local groundwater. Since Townsend Farms is an active Cleanup site, I felt it might be most expeditious to address this issue through the current Cleanup project. Let me know what you think. Steve Fortuna Site Assessment Specialist Be sure to visit DEQ's Cleanup Program at:
From: SEIDEL Paul
Sent: Tuesday, April 27, 2010 10:13 AM
To: FORTUNA Steve
Cc: WILLIAMS Robert K; JOHNSON Keith
Subject: RE: City of Fairview well contamination
From: FORTUNA Steve
Sent: Monday, April 05, 2010 9:09 AM
To: SEIDEL Paul
Cc: WILLIAMS Robert K; FORTUNA Steve; JOHNSON Keith
Subject: RE: City of Fairview well contamination
From: SEIDEL Paul
Sent: Monday, April 05, 2010 8:45 AM
To: FORTUNA Steve
Cc: WILLIAMS Robert K
Subject: RE: City of Fairview well contamination
From: FORTUNA Steve
Sent: Monday, March 15, 2010 3:43 PM
To: SEIDEL Paul
Cc: FORTUNA Steve
Subject: City of Fairview well contamination
DEQ Northwest Region
2020 SW 4th Avenue, Suite 400
Portland, OR 97201-4987
503-229-5166
FAX: 503-229-6945
e-mail: fortuna.steve@deq.state.or.us