In 2006, the department adopted a risk-based corrective action process, also known as RBCA (pronounced "Rebecca"). Adopting risk-based decision-making was initiated when the department decided to move away from using drinking water standards as the clean-up criteria for contaminated groundwater, when the groundwater was not and will not be used as drinking water. The risk-based corrective action process provides a framework for remediating, or cleaning up, contaminated sites based on the risks the contamination poses to human health and environmental as it relates to how the site is used, both now and in the future. For general information about risk-based corrective action, visit Missouri Risk-Based Corrective Action (MRBCA). For information about the MRBCA process the department uses to manage petroleum releases at petroleum storage tank sites, visit Tanks Risk-Based Corrective Action.
In 2009, the department, with the assistance of stakeholders, developed a risk-based corrective action rule to codify the process and its key elements and methodologies. The rulemaking process involved both the Clean Water Commission and the Hazardous Waste Management Commission. The Risk-Based Corrective Action Process rule, found in Code of State Regulations 10 CSR 25-18.018, was adopted in June 2009 and became effective on Oct. 31, 2009.
The RBCA guidance documents are provided below. Updates made to the April 2006 guidance in June 2006 and June 2008 have been incorporated into this version of the guidance. For information regarding any future changes, visit the department's MRBCA Revision Information webpage. If revisions are made, the guidance below will be amended.
Main Guidance
Complete Main Text
- Missouri Risk-Based Corrective Action (MRBCA) Technical Guidance - All Sections (April 2006, including all subsequent updates)
By Section
- Acknowledgements, List of Abbreviations, Table of Contents, List of Tables, List of Figures (April 2006)
- Section 1 - Background and Objective (April 2006)
- Section 2 - Overview of MRBCA Process (April 2006)
- Section 3 - Remediation Authorities in Missouri (April 2006)
- Section 4 - Management of Imminent Threat(s) (April 2006)
- Section 5 - Initial Site Characterization and Comparison with Default Target Levels and Water Quality Criteria (April 2006)
- Section 6 - Development and Validation of Conceptual Site Model (April 2006)
- Section 7 - Selection of Chemicals of Concern (COCs) for MRBCA Evaluation (April 2006)
- Section 8 - Tier 1 Risk Assessment (April 2006)
- Section 9 - Tier 2 Risk Assessment (April 2006)
- Section 10 - Tier 3 Risk Assessment (April 2006)
- Section 11 - Long-Term Stewardship for Risk-Based Corrective Action Sites (June 2008)
- Section 12 - Risk Management Plan (April 2006)
- Section 13 - References (April 2006)
Appendices
Complete Appendices
- Missouri Risk-Based Corrective Action (MRBCA) Technical Guidance - All Appendices (April 2006, including all subsequent updates)
By Section
- Appendix A - Updates and Revisions to the MRBCA Technical Guidance (April 2006)
- Appendix B - Default Target Levels and Tier 1 Risk-Based Target Levels (June 2006)
- Appendix C - Estimation of Representative Soil and Groundwater Concentrations (April 2006)
- Appendix D - Procedure for Review of the Risk-Based Corrective Action (RBCA) Decisions (April 2006)
- Appendix E - Development of Risk-Based Target Levels (April 2006)
- Appendix F - Ecological Risk Assessment Checklists (April 2006)
- Appendix G - A Method for Determining if a Water Bearing Unit Should Be Considered an Aquifer (December 2006)
- Appendix H - Measurement of Soil Vapor Levels (April 2006)
- Appendix I - Flexibility in Calculation of Tier 2 and Tier 3 Site-Specific Target Levels (April 2006)
- Appendix J - Appendix to Section 11 Long-Term Stewardship for Risk-Based Remediation Sites (June 2008)
- Appendix K - Data Quality Management Plan (April 2006)
- Appendix L - Definitions (April 2006)
- Appendix M - Site-Specific Background Concentrations (April 2006)
- Appendix N - Cleanup Levels for Surfaces and Building Interiors (April 2006)
- Appendix O - Soil Type Determination Guidelines (April 2006)