Hawai‘i State Department of Health

Office of Hazard Evaluation and Emergency Response

Evaluation of Environmental Hazards at Sites
with Contaminated Soil and Groundwater

Pacific Basin Edition
(Summer 2008, updated October 2008)

Published by: Guam Environmental Protection Agency

The document Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater – Pacific Basin Edition (EHE guidance, October 2008) is a technical report with accompanying electronic lookup tables and environmental models prepared for the Guam Environmental Protection Agency. The guidance can be downloaded from the links provided below. The guidance represents an update to guidance prepared for the Commonwealth of the Mariana Islands, Division of Environmental Quality in October 2005 (CNMI 2005).

The Pacific Basin edition of the EHE guidance follows similar guidance prepared by the Hawai’i Department of Health (“Hawai‘i Edition,” HDOH 2008). A comparison of the two guidance documents is provided in Volume 1 of the Guam EPA document. The Hawai‘i guidance in particular makes allowances for low-quality groundwater in some coastal zones, especially in the Honolulu area. No such allowances are made in Guam, however, where all groundwater is considered to be a valuable source of drinking water that warrants a high degree of protection.

The Pacific Basin edition of the EHE guidance relies heavily on published USEPA toxicity factors and water standards. Within the limitations noted in Volume 1 of the guidance (especially with regards to vapor intrusion hazards in cold climates), this helps make the Pacific Basin edition of the EHE guidance useful across a broad geographic area.

The Pacific Basin EHE guidance can be used to expedite the identification of potential environmental hazards at sites with contaminated soil and groundwater as well as assist in the cleanup and redevelopment of these properties. Specific topics discussed in the guidance include:

Introduction to Environmental Hazard Evaluations (EHEs);
Environmental Hazards associated with contaminated soil and groundwater;
Tier 1 Environmental Screening Levels (ESLs);
Decision Unit and Multi-Increment Sample Investigation Strategies;
Contaminants of Potential Concern at Petroleum Release Sites;
Contaminants of Potential Concern for Former Agricultural Lands;
Tier 2 screening levels for arsenic, dioxins and chlordane;
Preparation of Environmental Hazard Evaluation Reports;
Advanced Environmental Hazard Evaluation Approaches; and
Long-Term Management of Contaminated Sites.

Volume 2 of the guidance provides supporting documentation and detailed screening levels for the Tier 1 ESLs presented in Volume 1.

Environmental hazards considered in the screening levels include:

Soil:
▪Direct-exposure threats to human health;
▪Intrusion of subsurface vapors into buildings;
▪Leaching and subsequent threats to groundwater resources;
▪Threats to terrestrial habitats;
▪Gross contamination and general resource degradation concerns;

Groundwater:
▪Threats to drinking water resources;
▪Threats to aquatic habitats;
▪Intrusion of subsurface vapors into buildings;
▪Gross contamination and general resource degradation concerns;

Soil Gas:
▪Intrusion of subsurface vapors into buildings.

The presence or absence of possible environmental hazards at a site can initially be determined by comparison of representative site data to the Tier 1 ESL for target contaminants. If the Tier 1 ESL is exceeded, specific environmental hazard(s) that could be present can be determined by a comparison of data to screening levels the individual hazards noted above. This is automatically done in the ESL Surfer (see below).

The Tier 1 ESLs are considered to be conservative. 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 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 other considerations.

The results of this evaluation are summarized in a brief Environmental Hazard Evaluation. A preliminary EHE should be prepared as initial site data are obtained and used to guide completion of the site investigation. The final EHE should provide recommendations for additional actions at the site. This could include the need for additional site data, cleanup of the site to the Tier 1 ESLs, advanced evaluation of tentatively identified hazards, preparation of an Environmental Hazard Management Plan for long-term management of contamination, etc. A simple EHE may only be a few pages long and included as one section of a site investigation report. EHEs for more complicated sites might need to be prepared as completely separate reports. In most cases, a brief, properly prepared EHE will replace the need for a more detailed (and expensive), traditional human health or “baseline” risk assessment. The EHE guidance and associated screening levels are not an adequate substitute for ecological risk assessments, however, although they may be helpful in the identification of areas where such assessments are necessary.

The Tier 1 ESLs incorporate USEPA Regional Screening Levels (RSLs, May 2008; updated Sept 2008) as one of numerous references for published soil, water and air screening levels. As discussed in the user’s manual that accompanies the guidance, the USEPA RSLs cannot be used as a stand-alone tool to evaluate the need for additional actions at contaminated sites. The RSLs only address direct exposure of humans to contaminants in soil. Other potential environmental hazards are not considered (see above).

Copies of the Pacific Basin Edition of the EHE guidance and associated reference material can be downloaded from the links provided below. Refer to ‘Updates’ worksheet of the ESL Surfer file for summary of updates to the original, Summer 2008 edition of the lookup tables. Comments, suggestions and questions are welcome at any time and should be provided to the contact noted below.

For further information, please contact:

Guam:
Guam Environmental Protection Agency Administration Building 17-3304 Mariner Avenue Tiyan, Guam 96913	Telephone: 1-671-475-1658/59

CNMI:
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

Hawai‘i:
Attn: Roger C. Brewer Office of Hazard Evaluation and Emergency Response Hawai‘i State Department of Health 919 Ala Moana Boulevard, Room 206 Honolulu, Hawai‘i 96814	Telephone: 1(808)586-4328 E-mail: roger.brewer@doh.hawaii.gov

ELECTRONIC COPIES (Click on the link to download)

Pacific Basin EHE Guidance (pdf files)

PDF Files:
Volume 1 (March 2009) (1.2 Mb)
Volume 2 Appendix 1 (March 2009) (3.25 Mb)
Volume 2 Appendices 2-9 (March 2009) (10.39 Mb)

Excel Files:
Appendix 1 Tables (March 2009) (1.06 MB)

SUPPLEMENTAL MODELS IN EXCEL FORMAT (Unless Noted)

Vapor Unit Conversion (94 Kb)
Batch Test Soil Leaching Guidance (pdf, 215 Mb)
Batch Test Soil Leaching Model (123 Kb)
Tier 2 Soil Direct Exposure Model (252 Kb)
Groundwater Vapor Intrusion (95 Kb)

The write-protect password for all 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.

If you do not have the Adobe Acrobat Reader installed on your computer, you need to install it before you can view and print the downloadable PDF files. The Acrobat Reader is free and can be downloaded to your computer by clicking on the button:

ESL SURFER

ESL Surfer Mar 2009 (1.36 Mb)

The ESL Surfer is a searchable, electronic version of the ESL lookup tables (see link in the Electronic Copies section). The Surfer includes an option for the selection of “Unrestricted” versus “Commercial/Industrial Only” land use options (not included in earlier editions). “Unrestricted” land use implies that the land could be used for residential housing, schools, medical facilities or other purposes where children or people with compromised health may visit on a regular basis. Screening levels for a Commercial/Industrial Only land use category should be used with caution, however, and could require future land use restrictions on the property.

Use of the ESL Surfer to screen site data and expedite preparation of EHE reports is highly recommended. The Surfer automatically generates a summary page that can be included in reports. The Surfer also includes a glossary, a summary of information on the chemical selected and an overview of options for more advanced evaluations of environmental hazards.

To use the ESL Surfer you must have Excel 2003 or newer installed on you computer. Simply download the Surfer from the link below then double click on the file to open the program.

If you have trouble using the pulldown menus on the Surfer then remove the write protection (under the Tools menu). The password to unprotect the Surfer worksheets is “ESL.” The ESL Surfer is revised on a regular basis to reflect updates to the lookup tables in the ESL document. Please periodically check this webpage to ensure that you have the most up-to-date edition available.

References:

CNMI, 2005, Screening For Environmental Concerns at Sites with Contaminated Soil and Groundwater: The Commonwealth of the Northern Mariana Islands, Division of Environmental Quality, October 2005.

GEPA, 2008, Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Pacific Basin Edition (Summer 2008 and updates): Guam Environmental Guam Environmental Protection Agency, http://www.justice.gov.gu/CompilerofLaws/gar.html.

HDOH, 2008, Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Hawai‘i Edition (Summer 2008 and updates): Hawai‘i Department of Health, Hazard Evaluation and Emergency Response, http://www.hawaii.gov/health/environmental/hazard/eal2005.html.

USEPA, 2008a, Screening Levels for Chemical Contaminants: U.S. Environmental Protection Agency, May 2008 (updated September 2008), prepared by Oak Ridge National Laboratories, http://www.epa.gov/region09/waste/sfund/prg/.

Office of Hazard Evaluation and Emergency Response
Hawai‘i State Department of Health
919 Ala Moana Boulevard, Room 206
Honolulu, Hawai‘i 96814

Telephone:		(808) 586-4249
From Maui (toll-free):		984-2400 ext 64249
From Hawai‘i (toll-free):		974-4000 ext 64249
From Kaua‘i (toll-free):		274-3141 ext 64249
From Moloka‘i or Lāna‘i (toll-free):		(800) 468-4644 ext 64249
Fax:		(808) 586-7537
24-hour Hotline:		(808) 247-2191

Web page maintained by Marsha Mealey Last updated 31 Jul 2009

Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater Pacific Basin Edition (Summer 2008, updated October 2008) Published by: Guam Environmental Protection Agency