Vapor Intrusion in Massachusetts Gerard Martin

Transcription

1 Vapor Intrusion in Massachusetts Gerard Martin Chief Compliance, Enforcement and Brownfields Redevelopment Section Bureau of Waste Site Cleanup, MassDEP

2 Proposed MCP Amendments Relative to Vapor Intrusion Gerard Martin, Chief Compliance, Enforcement and Brownfields Redevelopment Section MassDEP, Bureau of Waste Site Cleanup Southeast Regional Office May 3, 2013

3 Proposed MCP Amendments Process Improvements: - Eliminate Tier I Permits - Simplify Tier Classification - Streamline AULs, Notices of AULs on NPL Sites More Ways to Achieve Closure More Transparent Closure Terms Updated Standards

4 Public Comment Process Public Hearing Draft is available for review, along with supporting documents at: newregs.htm#proposed Public Comments Due COB Friday, May 17, 2013

5 Proposed Vapor Intrusion (VI) Related Amendments

6 Tier Classification Amendments Phase I still the basis for Classification; still occurs one year from notification NRS scoresheet replaced by Tier I Criteria OHM above RCGW-1 in current drinking water source area Presence of an Imminent Hazard IRA where remedial action to address a CEP is required No subclasses of Tier I, except Tier ID (defaults)

7 Proposed VI-Related Amendments Clarify VI-related SRM conditions - when to look (that trigger 72 hr notification) Conditions of SRM include, but are not limited to: soil impacted with VOCs near the structure VOCs in the groundwater exceeding the GW-2 Standard within 30 feet of the building, and the average annual depth to groundwater in that area is 15 feet or less

8 Proposed VI-Related Amendments Conditions of SRM include, but are not limited to: VOCs in the groundwater exceeding 10X the GW- 2 Standard within 100 feet of the building; VOCs in the groundwater beneath or near the structure with an earthen floor, fieldstone or concrete foundation, significant cracks and/or a groundwater sump LNAPL within 30 feet of the building the potential for vapor migration along preferential pathways

9 Proposed VI-Related Amendments CEP amendments New definitions of Residential Dwelling & Living or Working Space Reduced IRA Status Report frequency for non-ih CEPs Clearer provisions for completing IRAs to address CEPs

10 Proposed VI-Related Amendments Incorporate VI considerations more clearly in Phases I & II; add CSM definition and documentation The Phase I Report (Nature and Extent of Contamination section) shall provide information and details on NAPL, if present, including and the approximate horizontal and vertical extent of NAPL contamination, as obtained from site investigations of scope and detail commensurate with release and site conditions

11 Proposed VI-Related Amendments Phase I & II: The Phase I Report shall evaluate the potential for oil and/or hazardous material migration by: a. air; b. soil; c. groundwater; d. soil gas; e. preferential flow pathways such as subsurface utility lines; and/or f. surface water, including sediments

12 Proposed VI-Related Amendments Phase I & II continued: The Phase I Report shall include a Conclusion Section containing: a summary of findings and statement of conclusions with respect to the site a preliminary Conceptual Site Model for the disposal site (including a preliminary LNAPL CSM, if LNAPL is present) the outcome of Initial Site Investigation Activities

13 Proposed VI-Related Amendments Phase I & II continued: The Phase II Report shall set forth in narrative and, to the extent possible, in maps, graphs, and tables, the final disposal site Conceptual Site Model, approach, methods and results of the Phase II - Comprehensive Site Assessment

14 Proposed VI-Related Amendments Phase I & II continued: The Environmental Fate and Transport of Oil and/or Hazardous Material section of the Phase II requires: the identification and characterization of existing and potential migration pathways including air, soil, groundwater, soil gas, preferential migration pathways such as subsurface utility lines, surface water, sediment, and food chain pathways an evaluation of the potential for soil, groundwater, or LNAPL to be a source of vapors to indoor air of occupied

15 Proposed VI-Related Amendments Phase I & II continued: The Phase II Report shall include a characterization of the nature, and vertical and horizontal extent of oil and/or hazardous material in the environment, including any and all source(s), and the presence and distribution of any NAPL The Phase II Conclusions, shall provide a thorough discussion of the final disposal site Conceptual Site Model (including a final LNAPL Conceptual Site Model, if LNAPL is present)

16 Proposed VI-Related Amendments Phases II Risk Assessment: The Risk Characterization shall contain a description of all existing or potential Migration Pathways, including, but not limited to soil, groundwater, soil gas, surface water, air, sediment and the food web The potential for oil and/or hazardous material migration along preferential pathways such as utility lines or corridors must be evaluated, where applicable

17 Proposed VI-Related Amendments Phases II Risk Assessment proposed VI changes: Exposure Point Concentrations shall be developed using analytical data gathered during the site investigation For indoor air, in the event that it is not possible to distinguish disposal site-related contamination from interior sources (ongoing operations), fate and transport models may be used to develop an EPC provided such models are technically justified and the modeling assumptions are clearly documented

18 Proposed VI-Related Amendments The Application of Remedial Additives Near Sensitive Receptors, including within 100 feet of a School, Daycare or Child Care Center or occupied Residential Dwelling is prohibited unless prior written approval is issued by MassDEP

19 Proposed VI-Related Amendments Proposed Changes to Phase Submittal Deadlines from Time of Tier Classification... Phase II submittal from 2 to 3 years Phase III submittal from 2 to 4 years Phase IV submittal from 3 to 4 years 19

20 VI-Related Amendments PERMANENT SOLUTIONS Permanent Solution with Conditions for Active SSD Systems (operated under permit and with AUL) PERMANENT SOLUTION With NO CONDITIONS NATURAL BACKGROUND NSR for Residential/ Unrestricted ACTIVITY & USE LIMITATION AUL & ENGINEERED BARRIER AUL & PERMIT NO AUL REQUIRED PERMANENT SOLUTION With CONDITIONS

21 Permanent Solution with Conditions AUL & Permit For Active Exposure Pathway Elimination Measures e.g., active sub-slab depressurization systems AUL to provide notice of obligations Permit to operate the system

22 Method 1 Standards - Proposed VI Revisions Update toxicity values In September, 2011, the USEPA released its Final Assessment for TCE on its Integrated Risk Information System ( IRIS ) which resulted in changes to the Target Risk Levels ORS updated Risk Assessment Short Forms to reflect new EPA Toxicity Values

23 Comparison of Changes in Target Risk Levels Using TCE Toxicity Values Method 3 Assessment Short Forms Imminent Hazard Residential Scenario Imminent Hazard Commercial Scenario Old Value 85 µg/m 3 (5-yr Cancer Risk 1x10-5 ) No Significant Risk 14 µg/m 3 (30-yr Cancer Risk 1x10-5 ) September 2011 IRIS Value 2 µg/m 3 (Subchronic Exposure Non-Cancer Risk HQ=1.0) 8 µg/m 3 (Subchronic Exposure Non-Cancer Risk HQ=1.0) 2 µg/m 3 (Chronic Exposure Non- Cancer Risk HQ=1.0)

24 Method 1 Standards - Proposed VI TCE Revisions Standard Old Value Proposed Value S-1/GW mg/kg 0.3 mg/kg S-1/GW-2 2 mg/kg 0.3 mg/kg S-1/GW-3 90 mg/kg 30 mg/kg GW-1 5 µg/l 5 µg/l GW-2 30 µg/l 5 µg/l GW-3 5,000 µg/l 5,000 µg/l

25 Changes to TCE Threshold Values Screening Values Old Value Revised Value Residential Sub-Slab Soil Gas Screening Value Residential Threshold Values (TV r ) Commercial/Industrial Sub-Slab Soil Gas Screening Values Commercial/Industrial Threshold Values (TV c ) 56 µg/m 3 28 µg/m 3 0.8µg/m µg/m µg/m µg/m 3 1.8µg/m µg/m 3

26 Source Control (5)(c) Parties conducting response actions shall seek to eliminate each Source of OHM Contamination In cases where such elimination is not feasible, response actions shall control each Source of OHM Contamination...

27 Source Elimination/Control Provide basic definition of Source of OHM Contamination refers to the original OHM release location and/or contaminated media from which OHM can migrate as a bulk material Source of OHM Contamination shall be eliminated, if feasible If not feasible, then Source must be controlled; performance standards for Source Control are specified

28 Proposed Definition Source of OHM Contamination Sources of OHM Contamination may include: leaking storage tanks, vessels, drums and other containers dry wells or wastewater disposal systems that are not in compliance with regulations governing discharges from those systems contaminated fill, soil and sediment sludges and waste deposits NAPL

29 Source Control Performance Standards Absence of Non-Stable NAPL Removal of LNAPL to extent feasible (using LCSM principles) OHM plumes in any media not expanding Absence of DNAPL constituent concentrations greater than 1% of their solubility limit

30 Questions?