Jump to main content.

Guidance for Implementation of the Saltwater Dissolved Oxygen Criteria

Sherry Poucher 1, James Keating 2, Kellie Kubena 2, Tonya Fish 2

1Science Applications International Corporation, Newport, RI
2 U.S. Environmental Protection Agency, Washington, D.C.

Effective indicators of ecosystem health related to hypoxia depend not only on the accuracy and precision of exposure measurements, but also the assessment endpoint used to evaluate potential stress. Because hypoxic conditions are highly variable (in both short and long term temporal scales) determining status and trends has always been challenging. EPA's saltwater dissolved oxygen (D.O.) criteria help by providing an approach that integrates exposure variability on daily and seasonal basis and that captures a broad range of biological responses, yielding assessment endpoints with more resolution than typical benchmark applications (e.g., 2 mg/L minimum or 5 mg/L mean). The assessment approach results in a cumulative annual impairment 'stress score' that facilitates comparison of conditions that vary from year to year, allowing improved determinations of status and trend. The criteria requirement to integrate both short term and seasonal data will ultimately guide strategies for improved monitoring. A new implementation guidance document for the D.O. Criteria has been developed to assist users in making the best use of the new assessment tools. It begins with an explanation of the technical basis for the new criteria, and how they are used to synthesize frequency, duration and magnitude components of various exposure scenarios. The document also suggests an implementation process to minimize uncertainties associated with application of the criteria. Finally, it provides examples of implementation for various types of D.O. regimes, illustrating a range of exposure data requirements for differing exposure scenarios and assessment needs.

Keywords: hypoxia, dissolved oxygen, criteria, monitoring

EMAP Home | About EMAP | Components | Data | Documents | Bibliography | News | Site Map

Local Navigation

Jump to main content.