Ultrafine Beryllium Number Concentration as a Possible Metric for Chronic Beryllium Disease Risk

Abstract

Beryllium is a lightweight metal which causes a chronic granulomatous lung disease among workers who become sensitized to it. Recent research has shown a persistence of the disease despite efforts at control with mean exposures below the Occupational Safety and Health Administration (OSHA) occupational exposure limit of 2 microg/m3. Results of our current research confirm a previous finding in certain plants that particle number concentrations are higher in areas where historical estimate of risk showed a high risk of disease despite relatively lower mass concentrations. By providing side-by-side measurements of both particle number and mass, this research adds support to the proposal that particle number rather than particle mass may be more reflective of target organ dose and subsequently a more appropriate measure of exposure for chronic beryllium disease. Our evidence also shows that particle mass exposure measurements and particle number exposure measurements were not correlated.

Chronic Beryllium Disease and Sensitization at a Beryllium Processing Facility

“…This has led researchers to examine the possible role of particulate size (Kelleher et al 2001; McCawley et al 2001) and skin exposure (Tinkle et al 2003). …”

“…We have no data to directly address whether skin exposure is of importance in the development of beryllium disease in this cohort. However, others have hypothesized that small particle size increases the likelihood of both inhalation and skin absorption and exposure (McCawley et al 2001). Our data showed the opposite results with reduced levels of exposure to fume, which would be the smallest particle size form of exposure that occurred in this facility, and CBD (Table 10).…”

“…One study found an exposure–response relationship for sensitization with CBD but not for sensitization without CBD (Viet et al 2000). Other work has addressed the possibility of particle size (McCawley et al 2001), skin absorption (Tinkel et al 2003), and/or genetic susceptibility (Saltini et al 2001) as important factors that confound a straightforward exposure–response relationship.…”

A Novel Alternative to Environmental Monitoring to Detect Workers at Risk for Beryllium Exposure-Related Health Effects

“…(6) possibly due to factors such as exposure misclassification and lack of accurate and/or biologically relevant exposure metrics. (7,8) The established particle size-selective criteria are based on the probability of an aerosol penetrating into the lung rather than depositing particulate matter. Penetration for sub-particulate matter is a constant 100%, while the extent of deposition fluctuates.…”

“…Respirable particles (1–10 µm) are the fraction of the aerosol that penetrates the tracheobronchial region and the elements that may enter the non-ciliated alveolar region, therefore making them more relevant to the development of inflammation and CBD. (8,9) …”