Annals of Occupational Hygiene Advance Access originally published online on May 2, 2008
Annals of Occupational Hygiene 2008 52(4):287-295; doi:10.1093/annhyg/men016
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Performance of Laboratories Analysing Welding Fume on Filter Samples: Results from the WASP Proficiency Testing Scheme
The Health and Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK
* Author to whom correspondence should be addressed. Tel: +44 (0) 114 2892645; fax: +44 (0) 114 2892544; e-mail: peter.stacey{at}hsl.gov.uk
This paper emphasizes the need for occupational hygiene professionals to require evidence of the quality of welding fume data from analytical laboratories. The measurement of metals in welding fume using atomic spectrometric techniques is a complex analysis often requiring specialist digestion procedures. The results from a trial programme testing the proficiency of laboratories in the Workplace Analysis Scheme for Proficiency (WASP) to measure potentially harmful metals in several different types of welding fume showed that most laboratories underestimated the mass of analyte on the filters. The average recovery was 70–80% of the target value and >20% of reported recoveries for some of the more difficult welding fume matrices were <50%. This level of under-reporting has significant implications for any health or hygiene studies of the exposure of welders to toxic metals for the types of fumes included in this study. Good laboratories' performance measuring spiked WASP filter samples containing soluble metal salts did not guarantee good performance when measuring the more complex welding fume trial filter samples. Consistent rather than erratic error predominated, suggesting that the main analytical factor contributing to the differences between the target values and results was the effectiveness of the sample preparation procedures used by participating laboratories. It is concluded that, with practice and regular participation in WASP, performance can improve over time.
Keywords: air sampling analysis fume proficiency testing quality of data WASP welding
Received December 14, 2007; in final form March 13, 2008