Office of Hazard Evaluation and Emergency Response

Screening For Environmental Concerns at Sites With Contaminated Soil and Groundwater (Interim Final - October 2005)

The document Screening For Environmental Concerns at Sites With Contaminated Soil and Groundwater (October 2005) is a technical report prepared by Commonwealth of the Mariana Islands, Division of Environmental Quality. The document is modeled after a similar technical report prepared by California EPA and the Hawai’i Department of Health Screening For Environmental Concerns at Sites With Contaminated Soil and Groundwater (May 2005, updated August 2006). Information provided in the CNMI document is not intended to establish policy or regulation. Volume 1 of the document presents lookup tables of conservative Environmental Screening Levels ("ESLs") for over 100 chemicals commonly found at sites with contaminated soil and groundwater. Volume 2 describes how the ESLs were developed and provides detailed tables and appendices in support of the summary lookup tables. Excel spreadsheets for use in Tier 2 direct-exposure and soil leaching assessments are also provided, as is a PowerPoint presentation on the development and use of the ESLs.

The ESL document is intended to help expedite the assessment of contaminated sites for potential human health and environmental concerns. As an alternative to preparing "site-specific" screening levels or attempting to quantifying risk in a more formal risk assessment, data collected at a site can be directly compared to the ESLs and the need for additional work evaluated. It is anticipated that this document will be especially beneficial for use at small- to medium-size sites, where the preparation of a more formal risk assessment may not be warranted or feasible due to time and cost constraints.

The ESLs are considered to be conservative. ESLs based on human health and ecological concerns are well below levels that would cause immediate, acute health effects. Soil, groundwater and/or soil gas data collected at a site should be directly compared to the ESLs. Based on this comparison and a review of actual site conditions, potential environmental concerns can be quickly identified. Under most circumstances, and within the limitations described, the presence of a chemical in soil, soil gas or groundwater at concentrations below the corresponding ESL can further be assumed to not pose a significant long-term or “chronic” threat to human health and the environment. Additional evaluation will generally be necessary at sites where a chemical is present at concentrations above the corresponding ESL. Active remediation may or may not be required, however, depending on site-specific conditions and considerations.

This evaluation is documented in an “Environmental Risk Assessment.” An outline of the information that should be provided in the text of the risk assessment is provided in Volume 1. While not required at most sites, an Environmental Risk Assessment may also include a traditional, detailed “Human Health” risk assessment as one part of that document (usually as an appendix). This expedited approach to site investigation, assessment and cleanup has been shown to be especially effective at sites with limited or relatively straightforward types of contamination, where the preparation of a more formal risk assessment may not be warranted or feasible due to time and cost constraints.

A worksheet for calculation of Tier 2, direct-exposure action levels has also been prepared (download below). The worksheet cannot be used as a stand-alone tool for a Tier 2 environmental risk assessment. All other potential environmental concerns must be included in the assessment (i.e., soil leaching, vapor intrusion, ecotoxicity, gross contamination, etc.). Refer to Volume 1, Chapter 3 of the ESL document for more information. Preparation of a Tier 2 spreadsheet and guidance for soil leaching concerns is currently under way.

The ESL document incorporates USEPA Region IX Preliminary Remediation Goals (“PRGs”) as one of up to five different types of action levels for evaluation of contaminants in soil. As discussed in the accompanying user’s manual, the PRGs are not intended to be used as “stand alone” criteria for evaluation of contaminated sites. The PRGs are only intended to address direct exposure of humans to contaminants in soil. Evaluation of additional concerns must be carried out separately. The ESL document offers one approach to accomplish this.

For further information, please contact:

Ray Masga Commonwealth of the Northern Mariana Islands
Division of Environmental Quality
Saipan, MP 96950-1304
Telephone: 1-670-664-8500
E-mail: ray.masga@saipan.com

Or
Roger Brewer, Ph.D
Hawai’i Department of Health
Hazard Evaluation and Emergency Response
919 Ala Moana Boulevard
Honolulu, Hawai’i 96816
Telephone: 1-808-586-4328
E-mail: roger.brewer@doh.hawaii.gov

ELECTRONIC COPIES:

PDF Files:
Volume 1 (457 K)
Volume 2 Appendix 1 (October 2005) (921 MB)
Volume 2 Appendices 2-7 (October 2005) (5 MB)

Excel Files:
Appendix 1 Tables (October 2005)
Appendix 1 Tables (October 2005) in Excel 2000 format
Tier 2 Direct-Exposure Spreadsheet (October 2005)
Tier 2 Direct-Exposure Spreadsheet (October 2005) in Excel 2000 format

The write-protect password for the Appendix 1 Excel file worksheets is “ESL.”

The pdf files can be read using Adobe Reader. Free copies of Adobe Reader are available for download from the Adobe website at: http://www.adobe.com/products/acrobat/readstep2.html.

ESL SURFER

The ESL Surfer is an easy-to-use, Excel-based program that allows you to retrieve soil, groundwater, surface water, indoor air and soil gas screening levels for the selected chemical and the selected site scenario. To use the ESL Surfer you must have Excel 2000 or newer installed on you computer. Simply download the Surfer from the link below then double click on the file to open the program.

The write protection function for the input worksheet of the EAL Surfer apparently malfunctions when the Surfer is accessed from some servers. If the Excel 2003 version of the Surfer asks you for a password when you try to select a new chemical, try downloading the Excel 2000 version and using it instead. If you still have a problem, open the file, go under the "Tools" pull down list, select "Protection" and then select "Unprotect". The password to unprotect the sheet is "EAL". The EAL Surfer is revised on a regular basis to reflect updates to the lookup tables in the EAL document. Please periodically check this webpage to ensure that you have the most up-to-date edition available.

UPDATES
The CNMI ESL document will be revised and updated as needed. Updates will be posted to this website and notification sent to persons on the CNMI ESL mailing list as well as the Hawai’i DOH mailing list. To be included on the mailing list, send a note to ray.masga@saipan.com or roger.brewer@doh.hawaii.gov.