1.1 This test method is applicable to the determination of calcium, magnesium, potassium, and sodium in atmospheric wet deposition (rain, snow, sleet, and hail) by flame atomic absorption spectrophotometry (FAAS) (1).2

1.2 The concentration ranges are listed below. The range tested was confirmed using the interlaboratory collaborative test (see Table 1 for a statistical summary of the collaborative test).

1.3 The method detection limit (MDL) as given in 1.2 is based on single operator precision. Detection limits vary by instrumentation. Laboratories may be able to achieve lower detection limits. The method detection limit for this method as described in 1.2 was determined in 1987 (2) .

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in 8.3, 8.7, 12.1.8, and Section 9.

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.