Hexavalent chromium is anthropogenic from a number of commercial and industrial sources. It readily penetrates biological membranes and has been identified as an industrial toxic and cancer-causing substance. Hexavalent chromium is a known inhalation irritant and associated with respiratory cancer (4).

Ambient concentrations of hexavalent chromium are well below detection limits of standard sampling methods, including Test Methods and D5281 (9).

Ambient atmospheric concentrations of hexavalent chromium provides a means of evaluating exposures in a manner that can be related to health-based risk levels. Collecting actual monitoring data provides improved basis for health assessments of potential exposures (2).

This test method provides step-by-step instructions for sampling and analysis of hexavalent chromium collected on sodium bicarbonate coated cellulose filters exposed to ambient air.

1.1 This test method specifies a procedure for the sampling and analysis of airborne particulate matter for hexavalent chromium in ambient air samples.

1.2 The method involves drawing 21.6 m³ ambient air (at 15 L/min for 24 hours) through a sodium bicarbonate cellulose acid washed filter. Atmospheric hexavalent chromium is stabilized on the alkaline coated filter.

1.3 This method uses ion chromatography with post-column derivatization with 1,5-diphenylcarbazide (DPC) and a Ultraviolet/Visible (UV/VIS) detector.

1.4 This method is applicable to the determination of masses of 0.10 to 20.0 ng of hexavalent chromium per sample without dilution.

1.5 This method is applicable for hexavalent chromium measurement in the atmosphere from 0.004 ng/m³ to 0.926 ng/m³ assuming a 21.6 m³ sample volume. The range can be increased using appropriate dilutions.

1.6 Interconversion of trivalent and hexavalent chromium during sampling is minimized to the extent possible by using these sampling procedures.

1.7 The corresponding method for workplace air samples is ASTM Test Method D6832.

1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.9 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.