ALABAMA RISK BASED CORRECTIVE ACTION …

1 ALABAMA RISK BASED CORRECTIVE ACTION GUIDANCE MANUAL Revision February 2017 NOTICE This document has been prepared to assist individuals in understanding the minimum necessary elements of conducting an environmental risk assessment. It is not intended as a substitute for the regulations and should not be used as such. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. The hyperlinks and citations provided in this document are for helpful reference and may be used in the development of a facility s risk assessment plans, reports, etc.

2 It should be noted that use of the provided hyperlinks and citations alone does not ensure Departmental approval/acceptance of such risk evaluations, plans, reports, etc. September 2005 Revised April 2008 Revised February 2017 The ALABAMA Department of Environmental Management does not discriminate on the basis of race, color, national origin, sex, religion, age, or disability. ARBCA (Revision 3) 2017 i TABLE OF CONTENTS Page SECTION BACKGROUND AND INTRODUCTION 1- 1 Introduction 1- 1 Applicability 1- 3 Coordination with Other States 1- 3 SECTION TARGET CONCENTRATIONS 2- 1 SECTION OVERVIEW OF THE UST ARBCA PROCESS 3- 1 Introduction 3- 1 Tiered Approach and R isk- BASED Target Levels 3- 1 The Overall Investigation Process with ARBCA 3- 3 The ARBCA Process Step by Step 3- 4 Anticipated Impacts on Site Costs 3- 4 ARBCA-Evaluator Qualifications 3- 5 SECTION INITIAL-RESPONSE

3 ACTIONS 4- 1 Selecting the Type of Initial Response 4- 1 Free-Product Removal 4- 1 Threats to Utilities 4- 1 SECTION SITE ASSESSMENT AND INVESTIGATION 5- 1 Chemicals of Potential Concern (COPCs) 5- 1 Site Assessment and Preliminary Investigation 5- 2 Site Assessment (SA) 5- 2 Preliminary Investigation (PI) 5- 2 Comprehensive Investigation (CI) 5- 2 Review of Site Conditions 5- 3 Performance of a Receptor Survey 5- 4 Evaluation of Threats to Utilities 5- 5 Subsurface-Data Collection Activities 5- 6 Surficial Soil Sampling 5- 8 Representative Soil and Groundwater Concentrations 5- 8 Recommended Laboratory Analytical Methods 5- 8 ARBCA (Revision 3) 2017 ii SECTION RISK- BASED EVALUATION.

4 GENERAL CONSIDERATIONS 6- 1 Land Use 6- 1 Determine Current Land Use 6- 2 Determine Most Likely Future Land Use 6- 2 On-site and Off-site 6- 3 Receptors 6- 3 Human-Exposure Pathways 6- 5 Pathways for Inhalation 6- 5 Pathways for Surficial Soils 6- 6 Pathways for Subsurface Soils 6- 7 Pathways for Groundwater 6- 7 Other Pathways 6- 8 Conceptual Site Model ( CSM) 6- 8 Point of Exposure (POE) 6- 9 Calculation of risks and Risk- BASED Target Levels (RBTLs) 6-10 Overview of the Sequence.

5 R SL Evaluation, RM-1 Evaluation, RM-2 Evaluation 6- 10 Calculation of Risk- BASED Target Levels (RBTLs) 6- 11 Target-Risk Level 6- 13 Quantitative Toxicity Factors 6-14 Physical Properties of the COPCs 6- 15 Exposure Factors 6- 15 Fate-and-Transport Parameters 6- 16 Soil Parameters 6- 16 Groundwater Parameters 6- 19 Other Fate-and-Transport Parameters 6- 22 Equations and Models 6- 24 Protection

6 Of Deeper Groundwater 6-24 Groundwater-Resource Protection 6- 24 Surface-Water Protection 6- 26 Estimating Sentry-Well (SW) Target Concentrations for Groundwater- Resource Protection and Surface-Water Protection 6- 27 Management and Control of Nuisance Conditions or Conditions Requiring Initial-Abatement Measures 6- 28 Ecological Exposure 6- 29 Surface Water 6- 29 Sediments 6- 29 Soils 6- 30 Lead

7 6- 30 ARBCA (Revision 3) 2017 iii SECTION REGIONAL SCREENING LEVEL EVALUATION 7- 1 When to Perform a Regional Screening Level Evaluation 7- 1 Comparison of Data with Preliminary Screening Values 7- 1 SECTION RISK MANAGEMENT-1 EVALUATION 8- 1 Characterization and Classification of the Site 8- 1 Development of the Site Conceptual-Exposure Model 8- 1 Calculation of risks and Development of RM-1 Target Levels 8- 1 Comparison of RM-1 Target Levels with Representative Concentrations 8- 2 Soils 8- 2 Surficial Soil

8 8- 3 Subsurface Soil 8- 3 Groundwater 8- 3 Surface Water 8- 4 Selection of the Next Course of ACTION 8- 5 SECTION RISK MANAGEMENT-2 EVALUATION 9- 1 Contents of an RM-2 Work Plan 9- 1 Implementation of the Work Plan 9- 1 Performance of an RM-2 Evaluation 9- 2 Conceptual Site Model 9- 2 Target Risk 9- 2 Exposure Factors 9- 2 Physical Properties 9- 2 Toxicological Properties 9- 2 Fate-and-Transport Parameters and Building Parameters 9- 2 Fate-and-Transport Models 9- 3 Calculation of Representative Concentrations 9- 3 RM-2 Groundwater Resource Protection Evaluation

9 9- 3 Vapor Inhalation Pathway Evaluation 9- 4 Source Water Assessment Areas 9- 4 RM-2 Surface Water Protection Evaluation 9- 4 Ecological Evaluation 9- 5 Evaluation of Other Pathways 9- 5 Risk-Management Recommendations 9- 5 SECTION RISK-MANAGEMENT ISSUES 10-1 Groundwater Monitoring 10-1 CORRECTIVE ACTION Plans 10-1 Land-Use Controls 10-2 No-Further- ACTION / CORRECTIVE ACTION Process Terminated Procedure 10-2 ARBCA (Revision 3)

10 2017 iv SECTION REFERENCES 11-1 APPENDICES Appendix A List of Acronyms Used in this Guidance Manual Appendix B Estimation of Representative Soil and Groundwater Concentrations Appendix C Concentrations Protective of a Stream Appendix D Back Calculation of Risk- BASED Target Levels a nd Forward Calculation of risks and Hazard Quotients Appendix E Models/Equations for Estimating RM-1 and RM-2 Target Levels Appendix F Models/Equations for Estimating risks Appendix G Development of a Site-Specific Biodecay Rate FIGURES Figure 3-1 Flow Diagram of the ARBCA Process (located at the end of Section 3) Figure 6-1 Graphical Display of a Conceptual Site Model (located at the end of Section 6) Figure B-1 Calculation of Groundwater Resource Protection Target Levels (located at end of Appendix B) Figure C-1 Schematic of Leachate Migration from the Soil Source to the Stream (located at the end of Appendix C) ARBCA (Revision 3) 2017 1-1 BACKGROUND AND INTRODUCTION INTRODUCTION The ALABAMA Department of Environmental Management (ADEM)