Fact Sheet

Rules Subgroup

Long Term Stewardship

Risk-Based Remediation Rule Workgroup Background

MRBCA - Tanks

Missouri Risk-Based Corrective Action (MRBCA)

Departmental Technical Guidance

The Risk-Based Corrective Action Technical Guidance is published by the Missouri Department of Natural Resources' Hazardous Waste Program.

The MRBCA process detailed in the guidance provides a policy for remediation decisions at contaminated sites.  The process helps create current and future site use while protecting human health and the environment.

The final draft of the guidance is posted here along with all subsequent updates.

Draft icon. Departmental Missouri Risk-Based Corrective Action (MRBCA) Technical Guidance
(Section 1-13) PDF (April 2006, including updates published in June 2006 and June 2008)

Draft icon. Departmental Missouri Risk-Based Corrective Action (MRBCA) Technical Guidance (Appendices) PDF (April 2006, including updates published in June 2006 and June 2008)

June 25, 2008 - Revised Section 11 and Appendix J

Please replace the April 2006 version of Section 11 and Appendix J of the guidance with these revised versions: Section 11 PDF and Appendix J PDF. Both have been incorporated into the version of the guidance above. Section 11 has been revised to reflect the passage into law of the Missouri Environmental Covenants Act and to provide further guidance regarding the content and application of Environmental Covenants. Appendix J has been revised to include a department-approved model Environmental Covenant. The revisions to Section 11 and Appendix J are effective immediately.

Dec. 15, 2006 - Revised Appendix G

Please replace the April version of Appendix G, "A Method for Determining if a Water Bearing Unit Should Be Considered an Aquifer," with this December 2006, version of Appendix G. The entire appendix is being replaced. The conversion factor, used to convert a hydraulic conductivity value measured in gpd/ft2 to cm/sec, is in error in the April version. Therefore, the solutions to Examples 1 and 2 were wrong and have been revised. The revision is effective immediately.

Nov. 7, 2006 - ERRATA Notice

The department is issuing an Errata Notice 17KB PDF that applies to Appendix B, Table B-1 (Default Target Levels), June 2006, version. The notice pertains to the following Chemicals of Concern: vinyl chloride, TPH-GRO and TPH-DRO.

Oct. 20, 2006 - MRBCA Policy about Off-site Groundwater Contamination

The department has developed a "Policy Statement to Be Incorporated in the MRBCA Guidance" 20KB PDF which covers closures of sites under MRBCA with off-property groundwater contamination. Effective Oct. 12, 2006, it is applicable to all sites that are remediated under the MRBCA Technical Guidance. For more information about this policy, please contact Carey Bridges, Chief, Brownfields/Voluntary Cleanup Unit by e-mail or telephone at 573-526-9830.

June 20, 2006 - Updates to the Technical Guidance

The following sections of the Departmental Risk-Based Corrective Action Technical Guidance have been updated or revised, and they replace the existing versions in the April 2006 draft. These revisions do not constitute substantive or policy changes. 

An explanation of the revision follows each update. Please note that these new updates are sub-labeled with the date of June 2006, which provides information that it is a later update to the April 2006 version.

Appendix B PDF - This section has been revised to include target levels for total TPH as well as some minor editorial changes.

Appendix E, Tables E-1 to E-3 PDF - The chemicals in this section has been reorganized so that the VOCs and SVOCs are no longer listed separately. In addition, please note that the toxicity values and the physical and chemical properties for petroleum-related chemicals are now included in this table. This information is based upon the same decisions/hierarchies that were made in the Risk-Based Remediation Rule Workgroup and that apply to all other chemicals in the departmental guidance.

Appendix E, Figure E-3: Figure E-3 PDF - This has been updated to reflect changes brought about by changes in the Water Quality Standards (the mixing zone concept and comparison to acute criteria were dropped for Class C streams). In addition, both Figures E-2 and E-3 were improperly numbered, so their titles were changed.

Figure 2-2 PDF - The MRBCA Process Flowchart was changed to more accurately reflect the broad role of Risk Management in site decisions, which may include clean-up, activity and use limitations, or some combination of both.

Figure 6-2 PDF - This figure was simplified, which should make it easier to read and follow.

Technical Guidance Sections listed individually: (April 2006, plus all subsequent updates published in June 2006 and June 2008)

Technical Guidance Appendices listed individually: (April 2006, plus all subsequent updates published in June 2006 and June 2008)