USGS - science for a changing world

USGS Water-Quality Information

*  Home *  Data *  Methods *  Labs *  Publications *  Topics *  Programs *  Contact Us [an error occurred while processing this directive] *  Intranet
 [Photo: USGS scientist collects water-quality samples.]

USGS scientists deploy SPMD and POCIS samplers to collect waterborne contaminants in Manoa Stream on Oahu, Hawaii.


Press Releases

Featured Science:

Past featured science...

Water Quality Data

Today's Water Conditions

Get continuous real-time water-quality measurements from Water-Quality Watch maps.
[Sample Water-Quality Watch Map]

Water Quality Portal (WQP)

Get current and historical USGS and EPA water-quality data at the WQP.


Get stream ecosystem aquatic bioassessment data from BioData.

For More Data

View a complete list of USGS water-quality data resources.

USGS in Your Area

USGS Water Science Centers are located in each state.

 [Map: There is a USGS Water Science Center office in each State.] Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii and Pacific Islands New York Vermont New Hampshire Maine Massachusetts South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.
 [image: beaker]

Chapter A6. Field Measurements

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

6.4 pH, Version 2.0 dated 10/2008

Revised By G.F. Ritz and J.A. Collins

This section of Chapter 6 is available as a pdf file:
6.4, Version 2.0 (dated 10/2008) [195KB PDF]

Download a copy of Adobe Acrobat Reader for free.


Measurement of pH is critical to the understanding of the viability and vulnerability of environmental waters and is considered a master variable in determining the aqueous geochemistry of an aqueous system. pH is a measure that represents the hydrogen-ion concentration (activity) of a solution. This section of the National Field Manual (NFM) describes U.S. Geological Survey (USGS) guidance and protocols for measurement of pH in ground and surface waters.


6.4 - pH

6.4.1 Equipment and supplies

6.4.2 Maintenance of pH instruments

6.4.3 Calibration of the pH instrument system

6.4.4 Measurement

6.4.5 Troubleshooting

6.4.6 Reporting

6.4.7 Selected References

6.4.8 Acknowledgments

 [Back] Return to Chapter A6 Contents Page

 [Back] Return to Field Manual Table of Contents

Section 6.4 Archived versions:

USGS Home Water Climate and Land Use Change Core Science Systems Ecosystems Energy and Minerals Environmental Health Natural Hazards

Accessibility FOIA Privacy Policies and Notices logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: USGS Office of Water Quality
Page Last Modified: Wednesday, 28-Dec-2016 18:52:04 EST