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Assessment of respirable crystalline silica analysis using proficiency analytical testing results from 2003-2013.

Authors
Harper-M; Sarkisian-K; Andrew-M
Source
J Occup Environ Hyg 2014 Oct; 11(10):D157-D163
NIOSHTIC No.
20044983
Abstract
Analysis of Proficiency Analytical Testing (PAT) results between 2003 and 2013 suggest that the variation in respirable crystalline silica analysis is much smaller today than it was in the period 1990-1998, partly because of a change in sample production procedure and because the colorimetric method has been phased out, although quality improvements in the x-ray diffraction (XRD) or infrared (IR) methods may have also played a role. There is no practical difference between laboratories using XRD or IR methods or between laboratories which are accredited or those which are not. Reference laboratory means (assigned values) are not different from the means of all participants across the current range of mass loading, although there is a small difference in variance in the ratios of all participants to reference laboratory means based on method because the reference laboratories are much more likely to use XRD than are the others. Matrix interference does not lead to biases or substantially larger variances for either XRD or IR methods. Data from proficiency test sample analyses that include results from poorly performing laboratories should not be used to determine the validity of a method. PAT samples are not produced below 40 ug and variance may increase with lower masses, although this is not particularly predictable. PAT data from lower mass loadings will be required to evaluate analytical performance if exposure limits are lowered without change in sampling method. Task-specific exposure measurements for periods shorter than a full shift typically result in lower mass loadings and the quality of these analyses would also be better assured from being within the range of PAT mass loadings. High flow rate cyclones, whose performance has been validated, can be used to obtain higher mass loadings in environments of lower concentrations or where shorter sampling times are desired.
Keywords
Silicates; Silica-dusts; Exposure-levels; Risk-factors; Analytical-methods; Sampling; Analytical-processes
Contact
Martin Harper, Exposure Assessment Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., MS-3030, Morgantown, West Virginia 26505
CODEN
JOEHA2
CAS No.
14808-60-7
Publication Date
20141001
Document Type
Journal Article
Email Address
mharper@cdc.gov
Fiscal Year
2015
NTIS Accession No.
NTIS Price
Identifying No.
M092014
Issue of Publication
10
ISSN
1545-9624
NIOSH Division
HELD
Source Name
Journal of Occupational and Environmental Hygiene
State
WV
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