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CNMI Environmental Screening Levels (2015)

The Commonwealth of the Northern Mariana Islands, Division of Environmental Quality has prepared an Environmental Screening Levels (ESLs) document in 2005, updated 2015 Preparation of this document was sponsored by a Grant to the CNMI from the US Environmental Protection Agency Region IX The CNMI DEQ ESLs are 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)

The ESLs are based entirely on USEPA toxicity factors and surface water standards.The ESLs are a handy tool to informally screen sites outside of the USA as well as areas in the US mainland where comprehensive, local guidance is not available. Information provided in the CNMI document is not intended to establish policy or regulation.

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 quantify 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 a 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 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.

ELECTRONIC COPIES:

Pdf Files:

Excel Files:

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.

Presentation:

ESL SURFER: The ESL Surfer is an easy-to-use, Excel-based document 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 (March 2015) you must have Excel 2000 or newer installed on your computer Simply download the Surfer from the link below then double click on the file to open the program.

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