USGS collects data at the Birds Point-New Madrid Floodway

Noteworthy

National & Regional Science:

• Circular 1383-G: USGS Water Science Strategy – Observing, Understanding, Predicting, and Delivering Water Science to the Nation
• OFR 2013-1054: User's Manual for the National Water Information System of the USGS
• New water-quality test for preventing unnecessary beach closures
• OFR 2012-5228: Organic contaminants, trace and major elements, and nutrients in water and sediment sampled in response to the Deepwater Horizon oil spill
• Fact Sheet: Tracking and Forecasting the Nation's Water Quality Priorities and Strategies for 2013–2023

Local Science Features:

• New Hampshire: Concentrations of Chloride and Sodium in Groundwater in New Hampshire From 1960 Through 2011
• Arkansas: No Contamination from Fayetteville Shale Exploration Found in Sampled Wells

Past listings...

Water Quality Data

National Water Information System (NWIS)

NWIS provides current and historical water-quality data.

Today's Water Conditions

Water-Quality Watch provides continuous real-time water-quality measurements.

Water-Quality Web Services

Web services automate the sharing of USGS and USEPA water-quality monitoring data.

For More Data

Additional water-quality data resources are available.

USGS in Your Area

USGS Water Science Centers are located in each state.

Chapter A6. Field Measurements

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

6.6 Alkalinity and Acid Neutralizing Capacity

Revised By S.A. Rounds

This section of Chapter 6 is available as a pdf file:
6.6 Alkalinity and Acid Neutralizing Capacity (Version 4, dated 9/2012) [665 KB PDF]

Download a copy of Adobe Acrobat Reader for free.

Abstract

Alkalinity (determined on a filtered sample) and Acid Neutralizing Capacity (ANC) (determined on a whole-water sample) are measures of the ability of a water sample to neutralize strong acid. Alkalinity and ANC provide information on the suitability of water for uses such as irrigation, determining the efficiency of wastewater processes, determining the presence of contamination by anthropogenic wastes, and maintaining ecosystem health. In addition, alkalinity is used to gain insights on the chemical evolution of an aqueous system. This section of the National Field Manual (NFM) describes the USGS field protocols for alkalinity/ANC determination using either the inflection-point or Gran function plot methods, including calculation of carbonate species, and provides guidance on equipment selection.

Contents

Alkalinity and acid neutralizing capacity

6.6.1 Equipment and supplies

6.6.1.A Maintenance, cleaning, and storage

6.6.2 Calibration and standardization

6.6.3 Collection and processing

Surface water

Groundwater

6.6.4 Measurement

6.6.4.A Titration systems and procedures

Digital titrator

Buret titrator

6.6.4.B Inflection point titration method

6.6.4.C Gran-function plot method

6.6.5 Calculations

6.6.5.A Alkalinity or ANC

6.6.5.B Carbonate-speciation equations for samples with pH < 9.2

6.6.5.C Computer-program analysis of titration data

6.6.6 Troubleshooting

6.6.7 Reporting

Selected references

Acknowledgments

Return to Chapter A6 Contents Page

Return to Field Manual Table of Contents

Section 6.6 Archived Versions:

• Original report dated 4/98 [135KB PDF]
• 2nd Edition dated 9/2001 (without comments) [700KB PDF]
• 2nd Edition dated 9/2001 with comment updates [pages 7, 44, 47, 50) [4.1MB PDF]
• Third Edition dated June 2008, updated to version 4 [414KB]