Three-Dimensional Visualization of “RFI Phase 1 Data” at the Envirosafe Landfills, Oregon, Ohio.

At the request of Oregon-area residents, the Technical Outreach Services for Communities (TOSC) Program has conducted a review of the Remedial Facilities Investigation Phase 1 Report submitted to the U.S. Environmental Protection Agency by Envirosafe Services of Ohio, Inc., on July 18, 2003. The investigation is part of a broader RCRA Corrective Action project at the ESOI site.  (For more information, visit http://www.tosc.msu.edu/envirosafe ). 

The Technical Outreach Services for Communities (TOSC) program promotes community involvement in environmental decision-making through educational and technical assistance services, and is funded under a grant from the U.S. Environmental Protection Agency.  TOSC is housed in the Midwest Hazardous Substance Research Center.  Participating universities include Purdue University , Michigan State University, Kansas State University , and the Virginia Polytechnic Institute and State University .

The Michigan State TOSC Program was contacted in September 2001 by Oregon residents, and asked to provide guidance on the contamination at the Envirosafe facility.  Specifically, TOSC was asked to examine if the contamination was moving off the boundaries of the facility and if the bedrock aquifer was contaminated.  Residents also expressed concern over the nature of the contamination (what chemicals have been found), and what media (soils, surface water, groundwater, and sediments) have been affected.

Residents also asked TOSC if the work currently being conducted at the site by ESOI, under the direction of the U.S. EPA and Ohio EPA, would result in a clear understanding of the extent of contamination, and if any ecological or human health impacts may have resulted (or may result in the future) from the ESOI site.  Because ESOI has not completely characterized the site (i.e., Phase 2 of the investigation remains to be completed) and has not completed a comprehensive risk assessment, TOSC is not able to comment on risks posed by the site.  The site may (or may not) pose risks; that issue will be addressed in subsequent reports from ESOI.  Instead, in this report TOSC focuses on 1) the potential for horizontal and vertical movement of contaminants on the ESOI site and 2) the potential for off-site migration of contaminants from the ESOI site.

To address these issues, MSU-TOSC conducted an extensive visualization of the ESOI site using the data provided by ESOI to U.S. EPA in the Phase 1 Report.  The visualization has been carried out using Interactive Ground Water (IGW).  IGW is a real-time, interactive visual software system for groundwater modeling and visualization (see http://www.egr.msu.edu/igw).  TOSC’s goal is to enable local residents and other interested parties to understand the extent of contamination at the ESOI facility through detailed, three-dimensional pictures of the contamination at the facility.

TOSC Findings

The landfill areas investigated by Envirosafe in the Phase I investigation have leaked contaminants downward through the ground (the tills) and towards the bedrock aquifer. Specifically, the MSU TOSC Program provides the following detailed findings and conclusions, based on a visualization of the data provided by ESOI in the Phase 1 Report. 

1.      The data from ESOI show that the landfill areas under investigation in the Phase 1 report are leaking contaminants. 

2.      The data from ESOI show that the majority of the monitoring wells reported in Phase 1 have concentrations ten times higher than the maximum contaminant level (MCL).  These levels are significantly higher than background levels.  The elevated levels were found throughout the areas under investigation, both horizontally and vertically, and in both the upper and lower tills.

3.      The data from ESOI show high concentrations of chemicals along the northern boundary of the ESOI property.  Concentrations are particularly high near the northwest portion.

4.      The data from ESOI show very high concentrations of contaminants in the immediate vicinity of the water lines that carry raw drinking water to the City of Toledo.  The highest concentration found was 9800 times the MCL.

5.      The data from ESOI show that the groundwater in the vicinity of Otter Creek has elevated levels of contaminants. The highest concentration found was 1666.7 times the MCL.

6.      The data from ESOI show high levels of contaminants in the sediments in Otter Creek, Gradel Ditch and in the ditch to the north of SWMU 5.

7.      The upper till is much more contaminated than the lower till.  The data show that samples collected from the wells in the upper till are frequently at levels greater than the MCL; specifically 57% of the upper till wells are at least 20 times higher than the drinking water standard.  Again, the MCL ratio for the upper till background wells was significantly less than 1.  Samples from the wells in the lower till are mainly greater than the MCL; 14 of the lower till wells show concentrations at least five times the MCL. This spatial trend indicates that contaminants have moved downward; they have leaked from the landfill cells under investigation and are probably still doing so.  The hydraulic conductivity, based on the concentrations in the lower till, is substantially greater than the “10^-8 centimeters/second” that ESOI has stated, and probably greater than 10^-7 cm/s.  Possible causes of the vertical movement of contaminants include the presence of sand pockets, fractures or heterogeneities in the geology.  The depth of contamination in the lower till also demonstrates that the conductivity is greater than 10^-7 cm/s. 

8.      The RFI Phase 1 data show primarily “non-detect” (no contaminants detected) in the bedrock aquifer.  However, TOSC is concerned that the current monitoring wells may be located (screened) too deeply to intercept any potential contaminants.  ESOI found high levels of contaminants immediately above the bedrock (i.e., in the lower till).  Given that contaminants will tend to move horizontally at the interface between the lower till and the bedrock, the bedrock wells should be screened with great care to intercept any contaminants.

9.     The high levels of contaminants near the northern boundary of the ESOI property (in the areas investigated by ESOI in the Phase 1 Investigation) raise concern over off-site movement of contaminants.  The northwestern corner of the property has particularly high levels.

10.     The high levels of contaminants near Otter Creek concern TOSC over possible contamination of Otter Creek from the ESOI property, particularly given the potential hydraulic connection between the landfill areas under investigation and Otter Creek.  The fluids level in wells in between the landfill and Otter Creek are about ten feet higher than the water level in Otter Creek.

11.     The high levels of contaminants near the City of Toledo water lines concerns TOSC.  In the unlikely event of a rupture of the lines, the trenches for the water lines could serve as preferential channels for contaminant transport, potentially moving contaminants to Otter Creek.  Further, standard engineering practice would recommend against placing water lines in such a location.

12.  The likelihood that humans or ecological receptors might be exposed to ESOI contaminants is unknown.  TOSC recommends that a comprehensive assessment of both current and future risks be conducted by ESOI using the information provided in the corrective action investigation.  TOSC concurs with Ohio EPA’s directive to ESOI that ESOI do significant additional sampling in Phase 2 of the Corrective Action investigation to gather data that would be used in a risk assessment.

Shu-Guang Li, http://www.egr.msu.edu/~lishug Department of Civil and Environmental Engineering A133 Engineering Research Complex Michigan State University East Lansing, MI 48824-1226 Phone: (517)432-1929 Fax: (517)335-0250 E-mail: lishug@egr.msu.edu