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Chapter A6. Field MeasurementsNational Field Manual for the Collection of Water-Quality Data (TWRI Book 9)6.6 Alkalinity and Acid Neutralizing CapacityRevised By S.A. Rounds This section of Chapter 6 is available as a pdf file: Download a copy of Adobe Acrobat Reader for free. AbstractAlkalinity (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. ContentsAlkalinity 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 Ground water 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: |