Hexavalent chromium in ambient air in the Netherlands. Results of measurements near wood preservation plants and at a regional site
Zeswaardig chroom in de buitenlucht in Nederland. Resultaten van metingen bij houtverduurzamingsbedrijven en op een achtergrondlocatie
Mennen MG, Koot W, van Putten EM, Ritsema R, Piso S, Knol-de Vos T, Fortezza F, Kliest JJG
RIVM Report 723101031
Cr(VI) concentrations in ambient air have been measured using four parallel systems. Cr(VI) in the sampled air was captured in the impingers filled with an alkaline solution. After sampling, Cr(VI) in the solutions was analysed with graphite furnace atomic absorption spectroscopy after complexing in an organic solvent and phase separation. A small amount of Cr(III) and Cr(VI) was added to two of the four impinger solutions to check for possible equilibrium shifts between Cr(III) and Cr(VI) during and after sampling. The detection limit was 0.1 ng m exp. -3 for 24 h sampling. Results of duplicate measurements differed by 10% (average). The efficiency of the systems for sampling inhalable particles was determined using generated aerosol. Cr(VI) concentrations were measured near three wood preservation plants and at a background site. The Cr(VI) concentrations near the sources were 0.02 to 4 mug m exp. -3, while at the enclosure borders of the plants Cr(VI) levels did not exceed 20 ng m exp. -3. Daily average Cr(VI) concentrations at the background site were generally below the detection limit of 0.1 ng m exp. -3. From the results of the study it was concluded that the maximum permissible risk concentration of Cr(VI) in the Netherlands (2.5 ng m exp. -3) is probably not exceeded. Further, the ratio of Cr(VI) to total Cr was determined to be at most 5%, except near sources.