CASRN 14797-55-8

IRIS Assessment Plan for Nitrate and Nitrite (Scoping and Problem Formulation Materials, Suspended)


[UPDATE] EPA suspended the Nitrate and Nitrite assessment in fiscal year 2019. This assessment may be restarted as Agency priorities change. For more information, visit the IRIS Program Outlook (Apr 2019).


An IRIS Assessment Plan (IAP) communicates to the public the plan for assessing each individual chemical and includes summary information on the IRIS Program’s scoping and initial problem formulation; objectives and specific aims for the assessment; the PECO (Populations, Exposures, Comparators, and Outcomes) criteria that outlines the evidence considered most pertinent to the assessment; and identification of key areas of scientific complexity. The PECO provides the framework for developing literature search strategies and inclusion/exclusion criteria, particularly with respect to evidence stream (i.e., human, animal, mechanistic), exposure measures and outcome measures.


U.S. EPA. IRIS Assessment Plan for Nitrate and Nitrite (Scoping and Problem Formulation Materials, Suspended). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-17/331, 2017.

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Nitrate (NO3−) and nitrite (NO2−), naturally occurring anions in the environment, play an essential role in Earth’s nitrogen cycle. Since 1950, human sources of nitrogen have increased substantially, creating a global surplus of nitrate/nitrite that supersedes natural sources by about 30%. Nitrate salts are mainly used as nitrogen fertilizers and in industrial explosives, fireworks, and glass making, whereas nitrites are largely used as preservatives for meat and fish curing and as color fixatives.


Date Description
01-Sep 2017EPA released the IRIS Assessment Plan (IAP) for Nitrate and Nitrite for public comment and review. [Federal Register Notice Sep 18, 2017]
02-Sep 2017EPA's Science Advisory Board (SAB) Chemical Assessment Advisory Committee (CAAC) hosted a public meeting on September 27-28, 2017 to discuss the assessment. Information regarding the meeting can be found on the SAB website.
03-Apr 2019EPA suspended the assessment in fiscal year 2019. It may be restarted as Agency priorities change.

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