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Chapter A6. Field Measurements

National Field Manual for the Collection of Water-Quality Data (TWRI Book 9)

6.2 Dissolved Oxygen

Revised By Michael E. Lewis

This section of Chapter 6 is available as a pdf file:
6.2, Version 2.1 (dated 6/2006) [685KB PDF]

Download a copy of Adobe Acrobat Reader for free.

[August, 2011 -- This section is being revised to incorporate changes that have been made to the method for computing dissolved-oxygen solubility, as described in Water Quality Technical Memorandum 2011.03 and implemented in version 3 of DOTABLES software http://water.usgs.gov/software/DOTABLES/ ].

Abstract

Accurate data for the concentration of dissolved oxygen in surface and ground waters are essential for documenting changes in environmental water resources that result from natural phenomena and human activities. Dissolved oxygen is necessary in aquatic systems for the survival and growth of many aquatic organisms and is used as an indicator of the health of surface-water bodies. This section of the National Field Manual (NFM) includes U.S. Geological Survey (USGS) guidance and protocols for four methods to determine dissolved-oxygen concentrations: the amperometric, luminescent-sensor, spectrophotometric, and iodometric (Winkler) methods.

Contents

6.2 Dissolved Oxygen

6.2.1 Amperometric and luminescent-sensor methods

6.2.1.A Equipment and supplies

6.2.1.B Calibration

One-point and two-point calibrations

Correction for atmospheric pressure and salinity

Calibration procedures

1. Air-calibration chamber in air

2. Calibration with air-saturated water

3. Air-calibration chamber in water

6.2.1.C Measurement

Surface water

Ground water

6.2.1.D Troubleshooting (amperometric instruments)

6.2.2 Spectrophotometric method

6.2.2.A Equipment and supplies

6.2.2.B Calibration and interferences

6.2.2.C Measurement

6.2.3 Iodometric (Winkler) method

6.2.3.A Equipment and supplies

6.2.3.B Measurement

6.2.4 Reporting

6.2.5 Correction factors for oxygen solubility and salinity

Selected references

Acknowledgments

Return to Chapter A6 Contents Page

Return to Field Manual Table of Contents

Section 6.2 Archived Versions:

• Archive: 6.2, Version dated April 1998 (130KB PDF)
• Archive: 6.2, Version 2.0, dated May 2006 (1.3MB PDF)