Evaluation of Parameters Influencing Hexavalent Chromium Mist Sampling: A Full Factorial Design

Abstract

<em>A chromium electroplating bath with the ability to produce homogenous mist was used to evaluate parameters influencing hexavalent chromium (</em><em>Cr</em><em>⁺⁶</em><em>) </em><em>mist sampling methods. The results of 48 </em><em>Cr</em><em>⁺⁶</em><em>mist samples collected using t</em><em>he U.S. National Institute for Occupational Safety and Health method 7600</em><em>showed that </em><em>Cr</em><em>⁺⁶</em><em>concentration was higher: (1) For sampling by closed-face filter cassettes than for sampling by open-face filter cassettes (P <0.001); (2) for samples collected at 35 cm above the electroplating solution surface than for samples collected at 50 cm (P <0.001); (3) for sampling duration of 30 minutes than for sampling duration of 180 minutes (P <0.001); and, (4) for samples extracted immediately after sampling than for samples with delayed extraction (24 hours after sampling) (P <0.001). </em><em>It is concluded that the accuracy of Cr</em><em>⁺⁶</em><em> mist sampling in electroplating shops will be enhanced when: (1) closed-face filter cassette is used to prevent liquid splash contamination; (2) the recommended sampling height is 35 cm above the solution surface; (3) the sampling duration is short--approximately 30 minutes; and, (4) the extraction of the Cr</em><em>⁺⁶</em><em> sample is performed as soon as the sampling is completed.</em>