______________________________________________________________________ The Dow Chemical Company Midland, MI 48674 October 29, 2010 Ms. Mary Logan Remediation Project Manager U.S. Environmental Protection Agency, Region 5 77 West Jackson Chicago, IL 60604 Re: Task 1.3 Determination of the Need for Early Response Actions in EU010 and EU011-Revision 1-Settlement Agreement No. V-W-10-C-942 for The Tittabawassee River/Saginaw River & Bay Site Dow Submittal Number 2010-066 Ms. Logan: Attached please find the Task 1.3 Determination of the Need for Early Response Actions in EU010 and EU011-Revision 1. The document is being submitted under AOC CERCLA Docket No. V-W-10-C-942 and Appendix A, Statement of Work Schedule. Please feel free to contact me with any questions or concerns. Sincerely, The Dow Chemical Company Todd Konechne Project Coordinator cc: Al Taylor, MDNRE Diane Russell, U.S. EPA Joseph Haas, U.S. Fish and Wildlife Steve Lucas, Dow Peter Wright, Dow Greg Cochran, Dow
Transcript
______________________________________________________________________ The Dow Chemical Company Midland, MI 48674 October 29, 2010 Ms. Mary Logan Remediation Project Manager U.S. Environmental Protection Agency, Region 5 77 West Jackson Chicago, IL 60604 Re: Task 1.3 Determination of the Need for Early Response Actions in EU010
and EU011-Revision 1-Settlement Agreement No. V-W-10-C-942 for The Tittabawassee River/Saginaw River & Bay Site
Dow Submittal Number 2010-066 Ms. Logan: Attached please find the Task 1.3 Determination of the Need for Early Response Actions in EU010 and EU011-Revision 1. The document is being submitted under AOC CERCLA Docket No. V-W-10-C-942 and Appendix A, Statement of Work Schedule. Please feel free to contact me with any questions or concerns. Sincerely, The Dow Chemical Company
Todd Konechne Project Coordinator cc: Al Taylor, MDNRE
Diane Russell, U.S. EPA Joseph Haas, U.S. Fish and Wildlife Steve Lucas, Dow Peter Wright, Dow Greg Cochran, Dow
Task 1.3 Determination of the Need for Early Response Actions in EU010 and
EU011The Tittabawassee River/Saginaw River & Bay Site
4 Task 1.3 Characterization and Assessment Process 4 4.1 Property Owner Notification Process 4 4.2 Characterization and Assessment of EU Properties 4 4.3 Determination for Early Mitigation Measures Prior to Segment-Specific Work, Task 1.4 5
5 Task 1.3 Characterization and Assessment Results 6
6 Identified Data Gaps 7
7 Proposed Treatment for Identified Task 1.4 Areas 8
8 Proposed Task 1.4 Schedule 9
List of Tables
Table 1: List of EU 010 and 011 Properties Table 2: Task 1.3 Results Summary Table
DNRE Department of Natural Resources and Environment
RCRA Resource Conservation and Recovery Act
SOW statement of work
1
1 Introduction 1.1 Background
This Task 1.3 Report characterizes and determines the need for early response actions in exposure units (EUs) EU010 and EU011. This report was prepared in accordance with the requirements contained in Section IX (Work To Be Performed), Paragraph 21.a. of the Administrative Settlement Agreement and Order on Consent (AOC) for The Tittabawassee River/Saginaw River & Bay Site (Site) (Settlement Agreement No. V-W-10-C-942), and Section 1 of the Statement of Work (SOW, Attachment A of AOC), effective January 21, 2010.
The draft Task 1.1 Technical Memorandum was submitted to the U.S. Environmental Protection Agency (EPA) and the Michigan Department of Natural Resources and Environment (DNRE) (collectively, the Agencies) on March 22, 2010 to meet the requirement of Section 1.1 of the SOW. The AOC/SOW required that the Task 1.1 memorandum propose whether an identified area would be sequenced to start in Task 1.2, 1.3, or 1.4. Task 1.2 addresses areas where additional data are needed to complete the Task 1 evaluation. Task 1.3 addresses areas that require assessment to complete the Task 1 evaluation (including review of data collected under Task 1.2) to determine whether areas under consideration warrant an early response. Finally, Task 1.4 evaluates potential alternative response actions for those EUs and/or properties targeted (either in Task 1.1 or 1.3) for possible early action. All EU10 and EU11 areas specified in the Task 1.1 Technical Memorandum were sequenced into one or more of the three subtasks.
On May 3, Dow received comments from the Agencies on the Task 1.1 Technical Memorandum and partial approval to proceed with Task 1.3 activities in EU010 and EU011. All EU010 and EU011 parcels assessed during Task 1.3 are listed in Table 1. Locations of EU010 and EU011 are presented in Figures 1-3.
1.2 Task 1.3 Objectives As set forth in the SOW, the objective of Task 1.3 is to complete the characterization and assessment of Task 1 areas and to identify the potential need for early mitigation measures under Task 1.4, prior to segment-specific work. This Task 1.3 report focuses on the Agency approved EUs, namely EU010 and EU011, and property parcels within those EUs. The AOC stipulates that the Task 1.3 Report be submitted to the Agencies within 60 days after approval of the Task 1.1 Technical Memorandum, and this report fulfills that requirement.
2
2 Summary of Existing Data and Information Data and information used in the Task 1.3 assessment and characterization of EU010 and EU011 were obtained from the following sources.
• Final GeoMorph Site Characterization Report, Tittabawassee River and Floodplain Soils, Midland, Michigan. Ann Arbor Technical Services, Inc. June 15, 2009
• Electronic data from EPA sampling events at EU properties in 2008
• P1/P2 Action Database for EU010 and EU011
• The EU010 and EU011 boundaries and the property boundaries for parcels within EU010 and EU011 that were included in the Task 1.1 Technical Memorandum
The specific properties and early response activities previously conducted in EU010 and EU011 are discussed in Section 3.
3
3 Summary of Previous and Ongoing Work Dow and the Agencies have been performing early response actions to address residential properties located within the 8-year Tittabawassee River floodplain. Interim Response Activities (IRAs) were conducted for the Tittabawassee River floodplain under the regulatory authority of the terms of Dow’s Hazardous Waste Operating License (License) as issued under the authority of Michigan’s Part 111. The 8-year floodplain is defined by the March 2004 flood. Priority areas were identified where floodwater surrounded or approached residential properties during the March 2004 flood event.
Residential properties along the Tittabawassee were subdivided into Priority 1 (P1) and Priority 2 (P2), based on the proximity of March 2004 flood waters to residential structures, to sequence the implementation of mitigation measures under the State-approved IRA Work Plan, dated January 20, 2005. Dow attempted to contact all P1 and P2 property owners to offer an on-site visit by Dow representatives to evaluate mitigation options. Mitigation activities included the installation of exposure control barriers for exposed soil areas actively used by an owner, movement/replacement of gardens and flower beds to reduce flooding frequency, and house cleaning.
Under the approved IRA, 13 P1/P2 property owners in EU010 and EU011 accepted mitigation activities. Following subsequent flood events, owners of P1 and P2 properties have continued to be offered mitigation support, by request of the owners, including replacement or repair of previously installed mitigation measures that have been damaged or removed by the flood event.
4
4 Task 1.3 Characterization and Assessment Process Property assessments for EU010 and EU011 were conducted starting June 16 2010. The assessments focused on the portions of each property located within the 8-year flood boundary for these properties. The furan/dioxin levels outside of the 8-year boundary average between 10 ppt to 31 ppt within EU010 and EU011. Additionally, areas outside the 8-year flood boundary that where identified as potentially having soils relocated from within the floodplain were included in the land use assessments.
4.1 Property Owner Notification EU010 and EU011 residents were notified of the Task 1.3 land use assessment activities prior to the start of the Task 1.3 field work. Initial notifications were sent by EPA in a letter dated June 3, 2010. This letter explained the rationale for EU identification and also explained the objectives of associated Task 1 activities. A Dow representative then telephoned each EU010 and EU011 resident to schedule the Task 1.3 property land use assessment visit. A certified letter was sent to each resident who did not respond to this initial contact. Residents who did not respond to the certified letter were visited in person at their EU property. As of August 2, 2010, land use assessments have been conducted at 29 of the 44 EU010 and EU011 properties. Nine properties refused Task 1.3 activities, and no response was received from 6 properties. Table 1 documents the attempts to contact each resident to conduct a property land use assessment and the responses received from each residential property owner. Dow will submit a separate report documenting the best efforts that were used to attempt completion of Task 1 work and land use assessments of all properties within these EUs.
4.2 Characterization and Assessment of EU Properties The characterization and assessment of EU properties involved property visits and interviews with property owners or residents to document existing land use activities and to evaluate property conditions in the floodplain. Each property visit was completed within a single day. Each property was visited by two technicians to characterize and assess the property.
The characterization and assessments included:
• Documenting an interview with the property owners or renters focusing on existing land use activities
• Review of previous interviews and site visit information
• Property inspection
• Documentation of land use features, exposed soil, and other potential exposure locations on a site map
• Geographic Positioning System (GPS) survey of land use features and exposed soil areas locations
• Photographs of the property, land use features, and exposed soil areas
• Evaluation of previous P1/P2 Actions
5
The completed property use questionnaire, maps developed based upon information collected during the site inspection, and property photos are maintained in Dow’s file. The files will be retained in accordance with section XV of the Settlement Agreement (Retention of Records) and the Agencies will have access to the supporting information in accordance with Paragraph 51 of the Settlement Agreement (Data Availability). An example of the questionnaire utilized during the property inspections in provide in Appendix A.
Land use features and potential exposure locations typically included trails, lawns with exposed soil areas, fire pits, play areas, and gardens. Determination for Early Mitigation Measures Prior to Segment-Specific Work, Task 1.4
The identification of properties for early mitigation measures prior to segment-specific work building upon and incorporates certain aspects of the previously established P1/P2 IRA criteria, which identified the potential need for interim response activities on properties flooded by the March 2004 flood event that represents a 8-year flood event. This was based on the presumption that those properties contain furan/dioxin levels above the IRA action level unless otherwise established by sampling. Section II and Exhibit A of the SOW specify that the P1/P2 IRAs will transition to the Settlement Agreement. Therefore, determinations under Task 1 are intended to be consistent with those previous response actions and build upon the approach. The 2010 Task 1.3 characterization and assessment process, which established detailed property-specific information including current land use activities and the presence of exposed soils builds upon presumptive P1/P2 IRA approach, to establish the criteria used to identify EU010 and EU011 properties for sequencing into Task 1.4. In summary, the criteria for including properties or portions of properties, for potential early action under Task 1.4 are: the presence of exposed soil; and areas actively used by the residents of the property; and generally within the 8-year floodplain. In addition, properties that meet the Task 1 trigger criteria but have previously received adequate IRA exposure control mitigation measures are also sequenced into Task 1.4 for potential periodic maintenance. The Task 1.3 characterization and assessments provided a thorough approach to contacting and scheduling property visits and documenting existing land use and conditions within EU010 and EU011. This detailed assessment which builds on aspects of the previously-developed P1/P2 approach, provides a robust process for evaluating the properties against the criteria specified above, identifying areas for consideration under Task 1.4 for the Tittabawassee River EUs.
6
5 Task 1.3 Characterization and Assessment Results The Task 1.3 characterization and assessment results for EU010 and EU011 are summarized in Table 2. The areas within EU010 and EU011 that are proposed for early action under Task 1.4 also are listed in Table 2. Proposed mitigation methods for the areas identified in Table 2 are discussed in Section 7 of this report, and will be evaluated in an EE/CA or FS following Agency approval of this report and the Agencies’ determination of the need for mitigation measures in the EU010 and EU011 parcels.
Several properties within EU010 and EU011 were not recommended for sequencing into Task 1.4 because the criteria presented in Section 4.3 are not currently met. For these properties, Dow, working with the Agencies, will develop an approach to periodically assess whether conditions have changed at those properties that may warrant additional Task 1.4 evaluations. It is anticipated that this periodic assessment may include: Dow and/or the Agencies inquiring about changes to property conditions and use; contact with new owners if property is sold; and/or contact initiated by the property owners.
7
6 Identified Data Gaps No data gaps were identified during the Task 1.3 characterization and assessment activities at EU010 and EU011.
8
7 Proposed Treatment for Identified Task 1.4 Areas The AOC states that the Task 1.3 report shall, at a minimum, identify potential mitigation measures focusing on exposure control for areas where mitigation measures are determined to be necessary in advance of the Segment-Specific Response Proposal. Potential mitigation measures are summarized below:
Exposure Control Barriers
Dow anticipates that most Task 1.4 mitigation measures can be accomplished through the installation of exposure control barriers. An exposure control barrier provides immediate protection to the resident from potential exposure to soil contaminants, should they be present at the property (as discussed above, the P1/P2 process presumed the potential for soil with elevated dioxin/furan concentrations based on the extent of the March 2004 flood). Exposure control barriers can be designed to suit a range of conditions. One example of an exposure control barrier successfully used in the Tittabawassee River floodplain is the addition of a gravel layer added to floodplain trails in EU002.
Movement of Land Use Feature
There may be a situation where a particular land use feature, such as a garden or playground equipment, may be appropriately moved out of the floodplain to reduce or eliminate potential exposure to floods.
Maintenance of Exposure Control Measures
Maintenance of exposure control activities will be initiated by Dow, but may also include self-reporting on the part of the property owners.
All Task 1.4 mitigation measures will be selected, designed, and installed in cooperation with each resident.
9
8 Proposed Task 1.4 Schedule Following the completion of the Task 1.3 property use assessments a total of 16 properties from EU10 and EU11 are being sequenced into Task 1.4. The AOC stipulates that a Task 1.4 EE/CA or feasibility study (FS) Report be submitted to the Agencies for those areas sequenced into Task 1.4 within 120 days of receiving Agency approval of this Task 1.3 assessment report. It should be noted, that this schedule does not represent the schedule for those Task 1.4 areas identified in the Task 1.1 Tech Memorandum partially approved on May 3.
List of Tables Table 1: List of EU 010 and 011 Properties Table 2: Task 1.3 Results Summary Table
1Property was split from 11-21 based upon information obtained during the property assessment
Table 2Summary of Task 1.3 Assessment Activities
EU010 and EU011
Property Use within Floodplain
Exposed Soil Area
Previous Mitigation Measure
Adequate based upon Current
Use
Meets the P1/P2
Presumptive Criteria
EU010 Properties10-01 Yes Yes NA Yes Yes10-02 Yes Yes NA Yes Yes10-03 Yes No Yes Yes Yes2
10-04 Assessment Not Yet Completed10-05 Yes Yes NA Yes Yes10-06 Yes No NA Yes No10-07 Assessment Not Yet Completed10-08 Yes No Yes Yes No10-09 Assessment Not Yet Completed10-10 Assessment Not Yet Completed10-11 No No NA Yes No10-12 Assessment Not Yet Completed10-13 Assessment Not Yet Completed10-14 Assessment Not Yet Completed10-15 Assessment Not Yet Completed10-16 No No NA No No
EU011 Properties11-01 Assessment Not Yet Completed11-02 No No NA Yes No11-03 Yes Yes NA Yes Yes11-04 Yes Yes NA Yes Yes11-05 Yes Yes NA Yes Yes11-06 Yes Yes NA Yes Yes11-07 Yes Yes No Yes Yes11-08 Yes No NA Yes No11-09 Yes Yes Yes Yes Yes11-10 Yes Yes NA Yes Yes11-11 Yes Yes NA Yes Yes11-12 Assessment Not Yet Completed11-13 Assessment Not Yet Completed11-14 Assessment Not Yet Completed11-15 Assessment Not Yet Completed11-16 Assessment Not Yet Completed11-17 Yes Yes NA Yes Yes11-18 No Yes NA Yes No11-19 No Yes NA Yes No11-20 Assessment Not Yet Completed11-21 Yes Yes NA Yes Yes11-22 Yes Yes NA Yes Yes11-23 Yes Yes NA Yes Yes11-24 Yes Yes NA Yes Yes11-25 Yes Yes NA Yes Yes11-26 Yes Yes NA Yes Yes11-27 Yes Yes NA Yes Yes
11-28 1 Yes Yes NA Yes Yes2
1Property was split from 11-21 based upon information obtained during the property assessment 2 Property with areas outside the 8-year flood boundary that where identified as potentially having soils relocated from within the floodplain.NA-Not applicable based upon non-participation in IRA activities or only the completion of interior
IRA activities
Property # Sequence to Task 1.4
Task 1.3 Assessment Criteria Evaluation
List of Figures Figure 1: Exposure Unit Location Map
Section 1 Who lives at the residence: 1. How many people live at this residence? Age?
2. How long have you and your family lived at this residence?
Section 2: General information about the floodplain 1. Has the floodplain always been the way it is now or have you made changes to it
since you lived here? (example: changes to the land elevation, tree clearing) 2. Are you aware of any soil ever being relocated from the floodplain to other areas
of your property? If so, can you tell us where on your property?
Section 3: Property Use in the floodplain This section is related to the type of activities you do and your family members do in the floodplain and frequency. 1. Do you have walking paths in the floodplain? When you walk into the floodplain,
do you typically use walking paths? How often do you use it and how often do you not use the walking path?
2. Complete Table.
OUTDOOR AREA Yes/No Frequency/Additional Information Yard Work (mowing, raking, etc.)
Children’s play
Flower gardening
Vegetable gardening
Wood Cutting
Hunting
Fishing
Lawn sports/hobbies
Fire Pit
Picnic Table
Other
3. Do you ever go into the floodplain in the winter months? How frequently? 4. Are there any other activities you and your family members do on the
