NEMI Frequently Asked Questions

Q: What is NEMI?

A: NEMI, the National Environmental Monitoring Index, is a freely available compendium of information on a variety of what are broadly referred to as environmental “methods”. In NEMI, a method can be a traditional determinative method executed in a laboratory setting. Or, it could be a toxicity assay. Or a statistical technique reference for use in analyzing data. 

The majority of methods in  NEMI are the traditional laboratory determinative methods. However, the NEMI platform has grown to include information on field techniques, sensors, and even statistical methods useful in the environmental monitoring field. We continue to expand and refine the information and platform for making that information accessible.


Q: When  was NEMI created and by whom?

A: In 2002, the first iteration of the National Environmental Methods Index, containing about 400 methods,  was released. The NEMI database was developed by the National Water Quality Monitoring Council working in collaboration with partners in the federal, state, and private sectors with major funding from the U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (USEPA). 


Q: Why was NEMI created?

A: Every year, U.S. federal and state government agencies, industrial entities, academic researchers, and private organizations expend enormous amounts of time and money for monitoring, protecting, and restoring water resources and watersheds. Selecting appropriate analytical methods is a critical part of planning for monitoring projects and can be a complex project in itself. Methods must have sufficiently low detection levels, suitable precision and analyte recovery, and acceptable selectivity for a specific monitoring project’s needs.

Before NEMI, there were no uniform criteria to compare critical components of environmental analytical methods with each other or with a user’s project-specific needs. Instead, published methods typically focused on specific analytical objectives and ignored information that would allow users to assess whether data from one particular method will be comparable with data produced by other methods and project designs. NEMI was designed to make comparisons of methods and data more straightforward.  


Q: How often is the information in NEMI updated?

A: Methods are updated when that information is available; however, there is no schedule because methods are not updated on a set schedule. New methods are added as funding and user needs allow. If you would like a particular method added to NEMI, please let us know. We give highest priority to user requests. 


Q: How do I use NEMI to select the right method for my application? 

A: The selection of a method involves more than comparing cost, performance data, and detection level. However, these information are an important part of the planning process, and are indispensable for someone interested in comparing two historical water-quality datasets.

NEMI contains method summaries that include relevant information from which to make an objective scientific comparison of one method versus another, in terms of their ability to meet project-specific requirements. 

Many of the older methods in NEMI do not include all the information; however, when information is available, it is included in the database. The absence of critical information is, in itself, useful for methods comparison. 


Q: How can I access the full text of a method?

A: NEMI users can download the full text of the method, in PDF format, for publicly available methods. Private organizations that have submitted methods for inclusion in NEMI generally sell their methods. Links to websites for these organizations are included on the Method Summary Page. 


Q: What is the “analyte code”?

A: Most chemical analytes have a number that is assigned by the Chemical Abstract Services (CAS) Registry, a division of the American Chemical Society. Some analytes in NEMI are not distinct chemicals but are determined for regulatory purposes (ex: nitrate-plus-nitrite nitrogen). In these cases a unique identifier developed by EPA is assigned (ex: for nitrate-plus-nitrite nitrogen it is E-10128). Biological "analytes" such as brook trout have an analyte code based on the Integrated Taxonomic Information System (IT IS). In some cases, where no coding system formally exists, such as the case with “fish community”, an artificial analyte code was constructed for NEMI beginning with the letter ‘X’ followed by five numerals.


Q: Is there a reference guide to the terminology used in NEMI?

A: Yes, you can link directly from table headings in NEMI or browse the Glossary.


Q: How do I find an old method? 

A: When a new version of a method is published, the older version will be replaced in NEMI. The older method will be archived and still accessible, but it will not be searchable. Instead, the summary results page will be linked to the most recent method summary version. We understand that archiving is especially important for regulatory purposes; older methods and data must be available for comparison, historical, or other purposes such as litigation involving data obtained using older methods. Please send an email inquiry to and we will reply with the archived method as a file attachment.


Q: Whom do I contact for permission to use copyrighted materials?

A: All information on this site is public property. No permission is required to download methods from this site. 


Q: Can my organization's method(s) be included in NEMI?

A: Method information may be submitted by any public or private organization for consideration of inclusion. Guidelines for acceptance include public availability of the published full method by a governmental or private sector publisher. This includes methods that are associated with proprietary analytical instruments or equipment, copyrighted methods that are sold, and methods that support the determinative step (e.g., methods for sample collection, sample preparation, or in-situ analysis). Publication may be with a governmental or private sector publisher, and includes both printed and electronic formats. Methods that are published as research articles in journals or books are acceptable if procedures and performance are well documented, and there is evidence that the method has been successfully applied to a large number of environmental samples. 


Q: How can I effectively use the keyword search to get the results I want?

A: The keyword search will search both the database and any method .pdf files that may be loaded for a particular method. You can enter a whole or partial search term, or multiple terms with "AND" or "OR" between the terms to search for both/either terms in a method.


Q: Is there someone that I can contact for questions about or help with NEMI?

A: Please  submit inquiries via email at “” We will respond via email as soon as possible, or if you prefer that we call you, leave a phone number we will call you back during regular business hours.

Specific questions about a specific method should be addressed to the method author or representative. Method contact information is provided in the “Method Summary Information” page.


Q: How do I send feedback to the NEMI team? 

A: Send email to


Q: When should I contact the NEMI team?

A: Please contact us when you:

• discover an error in the method summary

• know of a new version of a method has been published and should be added to NEMI

• have a new method that you want to suggest be added or want permission to add methods on your own

• have feedback about your experience using NEMI