Risk-based Site Evaluation Process Guidance Documents

The Minnesota Pollution Control Agency (MPCA) has developed guidance outlining a risk-based approach to decision making during site investigation and remedy selection under the state's Voluntary Investigation and Cleanup (VIC) and Superfund Programs. The Risk-Based Site Evaluation (RBSE) Manual provides a tiered process for making decisions based on an evaluation of risks to human health and the environment. MPCA staff members with expertise in risk assessment, soil physics, hydrogeology, and remediation technologies have developed this guidance and accompanying risk evaluation spreadsheets that comprise the RBSE Manual.

The Risk-Based Site Evaluation Manual is composed of individual documents describing the process of site characterization, community involvement, evaluating the risk to human health and the environment posed at a site, and how to address that risk. Working drafts of the documents are now available. Additional documents will be made available as they are completed.

Note: The MPCA maintains a mailing list of all persons requesting draft documents so they can be notified of revisions and new documents. If you download electronic copies of the below documents, please send us your mailing address so we can keep you up to date; fax to 651-297-8676.

Remediation Division Policy on Analysis of Carcinogenic Polynuclear Aromatic Hydrocarbons (cPAH), June 2011

Effective immediately, analytical methodology for the vast majority of remediation sites will be the short list of seven cPAHs. However, under certain site conditions the extended list of 25 cPAH compounds will be recommended. The policy document provides background and situations where the extended list of 25 cPAH methodology applies.

• Remediation Division Policy on Analysis of Carcinogenic Polynuclear Aromatic Hydrocarbons (cPAH), June 2011 (c-rem3-03)

Use of Petroleum Remediation Corrective Action Design Guidance in the Superfund, RCRA and Voluntary Investigation and Cleanup Programs

In February 2011, the Petroleum Remediation Program (PRP) issued new guidance on conducting corrective actions at petroleum sites. The PRP released a suite of new guidance documents and report forms covering an updated corrective action design (CAD) approval process. This guidance is available on the PRP Publications Web page under the Corrective Action heading.

The MPCA Superfund, Resource Conservation and Recovery Act and Voluntary Investigation and Cleanup Programs have evaluated the PRP CAD guidance and will be utilizing the PRP CAD guidance as outlined in the following policy document.

• Superfund VIC RCRA CAD Guidance Policy (c-rem3-02)

The CAD Guidance will be used for new corrective action design, implementation, and management of active remediation activities at sites in the Superfund, Resource Conservation and Recovery Act and Voluntary Investigation and Cleanup Programs. The CAD guidance is available for use now; however, the official effective date is June 1, 2011. Please feel free to contact a program supervisor or program staff with specific questions regarding use of the guidance.

Currently available: Risk-based site evaluation publications

Fact sheets

Short, 1-3 page introductions to the risk-based site evaluation documents.

•  Air Impacts Evaluation
•  Community Involvement in Risk-Based Decision Making
•  Groundwater Guidance
•  Natural Attenuation of Chlorinated Solvents in Groundwater
•  Remedy Selection
•  Sediments - Human Health and Ecological Evaluation
•  Risk-Based Site Characterization and Sampling Guidance
•  Guidance on Incorporation of Planned Property Use into Site Decisions
•  Risk-Based Guidance for the Soil-Human Health Pathway User's Guide
•  Surface Water Pathway Evaluation
•  Best Management Practices for the Off-Site Reuse of Excess Fill from Development Sites (c-rem1-01)

Risk-Based Site Evaluation Manual - Introduction and Overview (September 1998, 6 pages) — A description of the risk-based site evaluation process, including a three-tier scheme for quantitative risk evaluation and analysis of selected pathways. Contact: Allen Dotson 651-757-2315

•  Introduction and Overview

Glossary of RBSE Terms and Concepts - an expanded glossary that offers succinct discussions of many RBSE concepts. Contact: Allen Dotson 651-757-2315

RBSE documentation checklist - Indicates steps in site characterization, risk assessment, and remedy selection process that warrant documentation. Refers to guidance documents that relate to each step, and suggests reporting structure that may expedite MPCA staff review. Contact: Allen Dotson 651-757-2315

•  RBSE Checklist

Site Characterization and Sampling Document - provides guidance on sampling and analysis requirements for site activities from investigation through closure. The document provides guidelines for the collection of data of sufficient quality and quantity to facilitate risk-based site evaluation, remedy selection, and remedy verification. Contact: Fred Campbell, 651-757-2260

•  Executive Summary
•  Document (September 1998, 95 pages)
• Example Sampling Protocol (for Groundwater)

Guidance on Incorporation of Planned Property Use into Site Decisions - The purpose of this guidance document is to summarize how planned property use may be incorporated into the investigation and cleanup decision-making process at Superfund and VIC Program sites as required by state Superfund law. Planned use of the property will be taken into consideration when setting cleanup standards and selecting response actions. Contact: Tom Schaub, 218-302-6603

•  Draft Guidelines, Guidance on Incorporation of Planned Property Use Into Site Decisions (September 1998, 29 pages)
• Affidavit Concerning Real Property Contaminated with Hazardous Substances (PDF Version) (c-rem4-02)
• Environmental Covenant and Easement (PDF Version) (c-rem4-03)
• Consent of Mortgage Form (PDF Version) (c-rem4-04)

Risk-Based Guidance for the Soil-Human Health Pathway - is designed to assist users in properly applying risk-based guidance for evaluating the human health risk caused by exposure to contaminated soil. The information in this document supersedes the guidance pertaining to the soil-human health pathway contained in the below, "Site Screening and Evaluation Document."

• Executive Summary
• User's Guide (August 1998, 24 pages)
• Draft Guidelines: Risk-based Guidance for the Soil - Human Health Pathway, Volume 2, Technical Support Document (January 1999, 287 pages)
• Tier 1 SRV Spreadsheet (6/09 - updated for PFBA, PFOA and PFOS only) (c-r1-01)
• Tier 2 SRV Spreadsheet (6/09 - updated for PFBA, PFOA and PFOS only) (c-r1-02)
• SRV changes memo (12/08)

Site Screening and Evaluation Document - presents an overall process for conducting a screening, or Tier 1 evaluation of the various exposure pathways at a site.

•  Executive Summary
•  Site Screening Evaluation Guidelines (April 1996, 57 pages)
•  October 1997 Interim Changes (6 pages)

Risk Based Guidance for Evaluating the Soil Leaching Pathway - provides guidance on use and development of contaminant specific soil leaching values (SLVs) for evaluating the risk to Groundwater at sites from the soil-to-Groundwater leaching pathway. The basis for and application of Tier 1 SLVs are presented and a step-wise procedure is presented for using site specific information for developing Tier 2 SLVs for making site corrective action decisions based on this pathway.

Contact: Rick Jolley, 651-757-2475

• Calculation Spreadsheet (Excel 5.0/95) (rev. 6/27/05)  (Note: this Excel spreadsheet includes macros and it must be saved as a downloaded file before it can be opened and viewed.)

Guidance for the Vapor Intrusion Pathway—is designed to assist users in properly applying risk-based guidance for evaluating the potential risks to human health caused by exposure to volatile compounds in buildings and structures that are due to vapor intrusion at sites within the MPCA Remediation Division.

Contact: Rick Jolley, 651-757-2475

• Risk-Based Guidance for the Vapor Intrusion Pathway (September 2008, 15 pages). This document was prepared for sites in the Superfund, RCRA and Voluntary Investigation and Cleanup (SRVC) programs. The intrusion screening values (ISVs) referenced in these guidance documents were developed by risk assessors in the MPCA Environmental Outcomes and Analysis Division.  Refer to the Excel™ spreadsheet below for updated ISVs. (c-s4-06)
• Intrusion Screening Values (02/09) Environmental Outcomes and Analysis Division (aq1-36)
• Background Information on the Intrusion Screening Values (September 24, 2008) (c-s4-08)
•  Vapor Intrusion Technical Support Document (August 2010) (c-rem3-01). This document provides technical support for the SRVC guidance document (September 2008) and includes updated vapor intrusion guidance for regulatory programs in Remediation Division.
•   Vapor Intrusion Interior Building Survey Form (c-rem3-01a). This document provides a consistent tool for reporting information on building characteristics, preferential pathways for vapor intrusion, and includes an indoor air quality survey for characterizing background sources of indoor air contaminants.

Surface Water Pathway Evaluation User’s Guide—This document is a user’s guide to evaluation of risk to surface waters, as potential or actual receptors of Groundwater plume contamination or through surface water runoff. It is part of a larger effort to develop guidelines for evaluating potential impacts to human health and the environment at sites that may require investigation or response action.

Contact: Barb Gnabasik, 218-302-6602

• Working Draft (c-s4-01)
• Appendices (file size = 2.6 MB) (c-s4-01a) 
  Table 8: Tier 1 Surface Water Screening Numbers for all Non-ORVW or OIRW Waters (c-s4-01b)
• Table 9: Tier 2 Surface Water Standards and Criteria for Classes 1B, 2A, 3A or 3B, 3C, 4A, 4B, and 5 Waters (c-s4-01c)
• Table 10: Tier 2 Surface Water Standards and Criteria for Classes 1B or 1C, 2Bd, 3A or 3B, 3C, 4A, and 5 Waters )c-s4-01d)
• Table 11: Tier 2 Surface Water Standards and Criteria for Classes 2B or 2C, or 2D, 3A or 3B or 3C or 3D, 4A or 4B or 4C, and 5 Waters (c-s4-01e)
• Table 12: Tier 2 Surface Water Standards and Criteria for Classes 7, 3C, 4A, 4B, and 5 Waters (c-s4-01f)

Groundwater Guidance Document - presents the framework through which the MPCA staff evaluate Groundwater contamination problems and manage decisions regarding remedial actions at sites. The guidance is based on managing risk associated with Groundwater contamination within the context of state and federal regulations.

Contact: Dave Scheer, 651-757-2693

• Executive Summary
• Document (September 1998, 20 pages)
• Drinking Water Criteria Spreadsheet (rev. 8/10) (c-w3-01)

Natural Attenuation of Chlorinated Solvents in Groundwater - defines the steps required to demonstrate that natural attenuation is a satisfactory remedy for Groundwater contaminated with chlorinated compounds such as trichloroethylene and tetrachloroethylene. The document first provides a simple screening evaluation process that is intended to indicate whether natural attenuation of these contaminants is a promising remedy alternative. This screening evaluation is followed by steps required to verify that natural attenuation is serving as an effective remedy at a site. A work plan checklist and recommendations for natural attenuation sampling are also included.

Contact: Mark Ferrey, 651-757-2355

•  Document (May 2000, Revised June 2006) (c-s4-05)

Guidance for Monitoring for Landfill Gas at and Near Former Dumps - provides guidance for monitoring of and responding to risks and hazards posed by methane and other landfill gases generated from abandoned unpermitted dumps to existing or proposed occupied structures.

Contact: Rick Jolley, 651-757-2475

• Guidance for Monitoring for Landfill Gas at and Near Former Dumps (c-rem3-04)

Remedy Selection - Once it is determined through the risk-based decision making process that a remedy is needed to reduce risk at an individual site, the remedy selection process begins. The intent of this document is to provide the most appropriate approach to remedy selection based on site specific circumstances.

Contact: Allen Dotson 651-757-2315

•  Executive Summary
•  Document (September 1998, 31 pages)

Document Availability

Printed copies of the above documents may also be requested. A photocopy fee of approximately $0.20 per page will be charged for requests in excess of 20 pages. Please fax your request to 651-297-8676.

Other Risk-based Site Evaluation Subject Areas

For the following subject areas, document development remains under consideration.

• Soil - Ecological Evaluation
• Sediments Evaluation (Ecological and Human Health)
• Soil Leaching Technical Support Document
• Air Impacts Evaluation