4.1 The test for cadmium is necessary because it is a toxicant and because there is a limit specified for cadmium in potable water in the National Interim Primary Drinking Water Regulations. This test serves to determine whether the cadmium content of potable water is above or below the acceptable limit.

1.1 These test methods cover the determination of dissolved and total recoverable cadmium in water and wastewater by atomic-absorption spectrophotometry and differential pulse anodic stripping voltammetry.2 Section 44 on Quality Control pertains to these test methods. Four test methods are included as follows:

Concentration
Range

Sections

Test Method A—Atomic Absorption,
 Direct

0.05 to 2.0 mg/L

7 to 15

Test Method B—Atomic Absorption,
 Chelation-Extraction

5 to 200 μg/L

16 to 24

Test Method C—Differential Pulse
 Anodic Stripping Voltammetry

1 to 100 μg/L

25 to 34

Test Method D—Atomic Absorption,
 Graphite Furnace

2 to 10 μg/L

35 to 43

1.2 Test Method B can be used to determine cadmium in brines. It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.

1.3 ICP-MS or ICP-AES may also be appropriate but at a higher instrument cost. See Test Methods D5673 and D1976.

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

1.5 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.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.