4.1 Most waters rarely contain more than trace concentrations of cobalt from natural sources. Although trace amounts of cobalt seem to be essential to the nutrition of some animals, large amounts have pronounced toxic effects on both plant and animal life.

1.1 These test methods cover the determination of dissolved and total recoverable cobalt in water and wastewater 2 by atomic absorption spectrophotometry. Three test methods are included as follows:

Concentration Range

Sections

Test Method A—Atomic Absorption,  Direct

 0.1 to 10 mg/L

7 to 16

Test Method B—Atomic Absorption,  Chelation-Extraction

10 to 1000 μg/L

 17 to 26

Test Method C—Atomic Absorption,  Graphite Furnace

 5 to 100 μg/L

 27 to 36

1.2 Test Method A has been used successfully with reagent water, potable water, river water, and wastewater. Test Method B has been used successfully with reagent water, potable water, river water, sea water and brine. Test Method C was successfully evaluated in reagent water, artificial seawater, river water, tap water, and a synthetic brine. It is the analyst's responsibility to ensure the validity of these test methods for other matrices.

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 11.8.1, 21.12, and 23.10.