LaMotte AM-21 Water Pollution Detection Outfit - Manual (Page 36)

pH Test
Most natural waters will have pH values from pH 5.0-8.5. Acidic, freshly
fallen rain water may have a pH value of pH 5.5-6.0. If it reacts with soils
and minerals containing weak alkaline materials, the hydroxyl ions will
increase and the hydrogen ions decrease; the water may become slightly
alkaline with a pH of pH 8.0-8.5. Sea water will have a pH value close to pH
8.0.
Waters more acidic than pH 5.0 and more alkaline than pH 8.5-9.0 should
be viewed with suspicion. Mine drainage and acid industrial wastes are the
principal factors in increasing the acidity of water, and alkaline industrial
wastes are the cause of high pH values.
The pH test, which is one of the most important tests for detecting industrial
pollution, is also one of the simplest to perform. *Range Finding Indicator
Solution (2220) contains several indicators. A specific color forms at each
pH as a result of the reaction between the water sample and the indicators
Field Test Method
Quantity Contents Code
60 mL *Range Finding Indicator Solution *2220-H
1 Test Tube, 5.0 ml 0230
WARNING: Reagents marked with a * are considered to be potential health hazards.
To view or print a Material Safety Data Sheet (MSDS) for these reagents see MSDS CD
or www.lamotte.com. To obtain a printed copy, contact LaMotte by email, phone or fax.
Procedure
1. Fill test tube (0230) to the 5.0 mL line with the sample water.
2. Add ten drops of the *Range Finding pH Indicator Solution (2220).
3. The color that results from the mixture will indicate the approximate pH
value of the sample. Check the color of the sample with the table below:
pH 3.0 Red pH 8.0 Green
pH 4.0 Red-Orange pH 9.0 Blue-Green
pH 5.0 Orange pH 10.0 Blue
pH 6.0 Yellow pH 11.0 Purple
pH 7.0 Yellow-Green
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