1. Sam Winer Motors Technical Outreach Support for Communities Michigan State University East Lansing, MI November 29, 2001

2. TOSC Program Provides assistance to communities affected by polluted sites Enables citizens to participate in cleanup decisions Inform, educate and empower Funded by U.S. EPA Agreement with CCAIC

3. Agenda Introduction Focus of investigations Where is the contamination? Is the contamination moving? Residential well sampling Conclusions & Recommendations

4. What has TOSC done? Reviewed documents produced by Ohio EPA and U.S. EPA Produced reports, including recommendations for further actions Published TOSC and AGENCY documents on the Web

5. Our Goals Tonight Build greater sense of understanding and participation Provide expert opinion Gather comments to be provided to EPA

6. Site cleanup process Site characterization Risk assessment, both human health and ecological Options for site remediation

7. Agenda Introduction Focus of investigations Where is the contamination? Is the contamination moving? Residential well sampling Conclusions & Recommendations

8. Focus of the investigation

10. Contaminants Chemicals from petroleum (gasoline) Toluene Benzene Metal Degreasers Trichloroethane Tetrachloroethane Plasticizers “phthalates” Others

11. Where is the contamination?

15. Site Geology

17. Where is the contamination?

21. Concentration (  g/kg soil) Contaminant MW-1S 4 to 6 ft. bgs MW-1S 12 to 14 ft bgs N-nitrosodiphenylamine 460,0001,600,000 Bis(2-ethylhexyl)phthalate 550,0001,500,000 1,2-Dichlorobenzene 7,40039,000 Isophorone 4,3003,600 Di-n-butylphthalate <LOD4,900 Phenol4,300 5,700

22. Is the contamination moving? On-site sampling from sandstone/shale aquifer has not revealed any contamination. Once contaminants reach the groundwater, significant migration is possible. Determining if these chemicals will reach the aquifer is difficult.

23. Is the contamination moving?

25. Difficult to answer due to potential problems associated with the U.S. EPA monitoring wells. No screening at top of aquifer Screening over different depths Measurements made only on January 3, 2001.

26. Estimating how long until the groundwater is contaminated Assume chemical is in non-native fill Glacial till conductivity Estimate range between 2.0x10 -7 ft/min (silt) 2.0x10 -9 ft/min (clay) Vertical Gradient Estimated from MW-1S & MW1D 0.733 ft/ft Assume 10% porosity Between 20 and 2,000 years

27. Residential Well Sampling EPA sampling focused on VOCs and “Base Neutral Compounds” Gasoline Plasticizers Pesticides Performed September 12 & 13, 2001

28. Residential Well Sampling Chemicals not found Acrolein Cyclohexanone BTEX Chemicals found Butyl benzyl phthalate: 0.20-0.26 ppb Di-n-butylphthalate: 1.1-2.5 ppb Bis(2-ethylhexyl)phthalate: 0.33-11 ppb

29. Agenda Introduction Focus of investigations Where is the contamination? Is the contamination moving? Residential well sampling Conclusions & Recommendations

30. Recommendations Further sampling of residential wells is warranted. Due to the presence of a number of phthalates in several residential wells Due to the presence of DEHP in one well at concentrations greater than the recommended value provided by U.S. EPA for drinking water

31. Recommendations Determine the hydrogeology of the glacial till layer Necessary to determine rate of vertical migration of water through this layer into the sandstone/shale aquifer This will determine the migration of chemicals present from the non-native fill layer to the sandstone/shale aquifer Will require measurements to be made during different seasons and after varying rainfall events

32. Recommendations Determine the hydrogeology of the sandstone/shale aquifer Necessary to determine rate of horizontal movement of water and chemicals off-site Will require measurements to be made during different seasons and after varying rainfall events

33. Recommendations Additional sampling is necessary to delineate contamination The U.S. EPA report states that “concentrations decrease an order of magnitude from 4-6 ft bgs and … another order or two of magnitude [sic] from 12-14 bgs to 20-22 ft bgs”. The data does not support this conclusion.

34. Recommendations The decision to close the site with no further action must be revisited. The presence of several chemicals (n- nitrosodiphenylamine, bis-(2-ethylhexyl) phthalate and total petroleum hydrocarbons at concentrations in the g/kg level is cause for concern. The lack of understanding of the groundwater hydrology further necessitates revisiting this decision.