Updates and Notices since April 2006

This page lists all updates to the departmental Missouri Risk-Based Corrective Action, or MRBCA, guidance since its initial publication in April 2006.  The guidance has been amended to incorporate each of the updates explained below.

June 25, 2008 - Revised Section 11 and Appendix J

The April 2006 versions of Section 11 and Appendix J of the guidance have been revised. Section 11 has been revised to reflect the passage into law of the Missouri Environmental Covenants Act, or MoECA, 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

Appendix G of the guidance, "A Method for Determining if a Water Bearing Unit Should Be Considered an Aquifer," has been revised. The entire appendix has been replaced. In the April 2006 version of the guidance, the conversion factor used to convert a hydraulic conductivity value from gallons per day per square foot (gpd/ft2) to centimeters per second (cm/sec), was in error. Therefore, the solutions to Examples 1 and 2 were incorrect.  The conversion factor and the solutions to the examples have now been corrected. The revision is effective immediately.

Nov. 7, 2006 - ERRATA Notice

The department is issuing an Errata Notice 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.  Table B-1 of the guidance available on-line has been updated accordingly.

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 - 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 - The chemicals in this section has been reorganized so that the volatile organic compounds, or VOCs, and semi-volatile organic compounds, or 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 - 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 - 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 - This figure was simplified, which should make it easier to read and follow.