Maine Department of Environmental Protection Remedial Action Guidelines for Contaminated Sites (RAGs) Effective Date: May 1, 2021 Approved by: ___________________________ Date: April 27, 2021 David Burns, Director Bureau of Remediation & Waste Management Executive Summary MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION 17 State House Station | Augusta, Maine 04333-0017 www.maine.gov/dep Maine Department of Environmental Protection Remedial Action Guidelines for Contaminated Sites Contents 1 Disclaimer ...................................................................................................................... 1 2 Introduction and Purpose ............................................................................................... 1 2.1 Purpose ......................................................................................................................................... 1 2.2 Consistency with Superfund Risk Assessment .............................................................................. 1 2.3 When to Use RAGs and When to Develop a Site-Specific Risk Assessment ................................. 1 3 Applicability ................................................................................................................... 2 3.1 Applicable Programs & DEP Approval Process ............................................................................. 2 3.1.1 Uncontrolled Hazardous Substance Sites ............................................................................. 2 3.1.2 Voluntary Response Action Program .................................................................................... 3 3.1.3 Brownfields ........................................................................................................................... 3 3.1.4 Superfund/CERCLA ................................................................................................................ 3 3.1.5 RCRA ...................................................................................................................................... 3 3.1.6 Petroleum Remediation Sites ............................................................................................... 4 3.1.7 Not Applicable to other DEP Programs ................................................................................. 4 3.1.8 Relation to Beneficial Reuse of Remediated Debris ............................................................. 4 3.2 Applicable Pollutants and Contaminants ...................................................................................... 5 3.2.1 Applicable to Hazardous Substances .................................................................................... 5 3.2.2 Applicable to Mixtures .......................................................................................................... 5 3.2.3 Applicable to Petroleum Only ............................................................................................... 5 3.3 Applicable Media, Scenarios and Routes-of-Exposure ................................................................. 5 3.4 Not Applicable to Ecological Risk .................................................................................................. 5 3.5 Not Applicable to Selection of COPCs for Full Risk Assessment ................................................... 6 3.6 Not Applicable to Radionuclides ................................................................................................... 6 4 Risk protocols Used to Develop the RAGs ....................................................................... 8 Effective May 1, 2021 Maine Department of Environmental Protection Remedial Action Guidelines for Contaminated Sites 4.1 RSL Calculator for Superfund Risk Assessments ........................................................................... 8 4.1.1 Target Risk Level for RAGs .................................................................................................... 8 4.1.2 Chronic or Subchronic Exposure ........................................................................................... 8 4.1.3 Additional Pathways ............................................................................................................. 9 4.1.4 Contaminant units, wet vs dry weight .................................................................................. 9 4.1.5 Complete Details on Derivation of RAGs and Factors ........................................................... 9 4.2 Definitions Used in The RAGs........................................................................................................ 9 4.2.1 Background Contaminants .................................................................................................... 9 4.2.2 Background Locations ......................................................................................................... 10 4.2.3 Contaminant ....................................................................................................................... 10 4.2.4 Contaminant or Chemical of Potential Concern (COPC) ..................................................... 10 4.2.5 Contaminant or Chemical of Concern (COC)....................................................................... 10 4.2.6 Environmental Covenant; Covenant ................................................................................... 10 4.2.7 Environmental Media Management Plan ........................................................................... 11 4.2.8 Exposure Pathway / Complete Exposure Pathway ............................................................. 11 4.2.9 Exposure Point .................................................................................................................... 11 4.2.10 Exposure Point Concentration ............................................................................................ 11 4.2.11 Hazard Quotient .................................................................................................................. 11 4.2.12 Hazard Index ....................................................................................................................... 12 4.2.13 Hazardous Substance .......................................................................................................... 12 4.2.14 Hazardous Substance Site ................................................................................................... 12 4.2.15 Incremental Lifetime Cancer Risk ....................................................................................... 13 4.2.16 Project Lead ........................................................................................................................ 13 4.2.17 Public Water ........................................................................................................................ 13 4.2.18 Sediment ............................................................................................................................. 13 Effective May 1, 2021 ii Maine Department of Environmental Protection Remedial Action Guidelines for Contaminated Sites 4.2.19 Urban Fill ............................................................................................................................. 13 5 Responsibilities ............................................................................................................ 13 5.1 Project Leads ............................................................................................................................... 14 5.2 BRWM Staff ................................................................................................................................. 14 5.3 BRWM Unit Supervisors .............................................................................................................. 14 5.4 BRWM Division Directors ............................................................................................................ 14 6 Where RAGs Fit in the Site Assessment and Remediation Process ................................. 14 6.1 Introduction ................................................................................................................................ 14 6.2 Emergency Removal .................................................................................................................... 14 6.3 Conceptual Site Model Development ......................................................................................... 15 6.4 Sampling ...................................................................................................................................... 17 6.4.1 Detection Levels & Data Quality Objectives ....................................................................... 17 6.4.2 Soil Sampling Depths ........................................................................................................... 18 6.4.3 Assessing Vapor Intrusion ................................................................................................... 18 6.4.4 The Chromium RAGs and Sampling for Chromium ............................................................. 18 6.5 Exposure Point Concentrations ................................................................................................... 18 7 Determine Target Clean-up Levels Using RAGs .............................................................. 19 7.1 Introduction ...............................................................................................................................