Cosmogenic (7)Be and (22)Na in ground level air in Switzerland (1994-2011).

We report monthly averages of weekly (7)Be and (22)Na concentrations in aerosol samples collected with high volume aerosol filters at 5 sampling sites in Switzerland from 1994 to 2011 ((7)Be) and from 2000 to 2011 ((22)Na). Monthly average concentrations of the two cosmogenic isotopes varied between 2600 and 4600 µBq/m(3) for (7)Be and between 0.2 µBq/m(3) and 0.5 µBq/m(3) for (22)Na. The (22)Na concentration in ground level air strongly increased from March to May, while a corresponding (7)Be increase was seen from March until July. The observed variations of the (7)Be and (22)Na activities together with the changes in the (7)Be/(22)Na ratio indicate input of stratospheric air between March and May, increased mixing of upper tropospheric air from June to August, and less exchange between the upper and lower troposphere in autumn and winter. Additionally, the 11-year solar cycle is clearly seen in the annual averages of the (7)Be concentrations.

Evaluation of historical beryllium abundance in soils, airborne particulates and facilities at Lawrence Livermore National Laboratory.

Beryllium has been historically machined, handled and stored in facilities at Lawrence Livermore National Laboratory (LLNL) since the 1950s. Additionally, outdoor testing of beryllium-containing components has been performed at LLNL's Site 300 facility. Beryllium levels in local soils and atmospheric particulates have been measured over three decades and are comparable to those found elsewhere in the natural environment. While localized areas of beryllium contamination have been identified, laboratory operations do not appear to have increased the concentration of beryllium in local air or water. Variation in airborne beryllium correlates to local weather patterns, PM10 levels, normal sources (such as resuspension of soil and emissions from coal power stations) but not to LLNL activities. Regional and national atmospheric beryllium levels have decreased since the implementation of the EPA's 1990 Clean-Air-Act. Multi-element analysis of local soil and air samples allowed for the determination of comparative ratios for beryllium with over 50 other metals to distinguish between natural beryllium and process-induced contamination. Ten comparative elemental markers (Al, Cs, Eu, Gd, La, Nd, Pr, Sm, Th and Tl) that were selected to ensure background variations in other metals did not collectively interfere with the determination of beryllium sources in work-place samples at LLNL. Multi-element analysis and comparative evaluation are recommended for all workplace and environmental samples suspected of beryllium contamination. The multi-element analyses of soils and surface dusts were helpful in differentiating between beryllium of environmental origin and beryllium from laboratory operations. Some surfaces can act as "sinks" for particulate matter, including carpet, which retains entrained insoluble material even after liquid based cleaning. At LLNL, most facility carpets had beryllium concentrations at or below the upper tolerance limit determined by sampling facilities with no history of beryllium work. Some facility carpets had beryllium concentrations above the upper tolerance limits but can be attributed to tracking of local soils, while other facilities showed process-induced contamination from adjacent operations. In selected cases, distinctions were made as to the source of beryllium in carpets. Guidance on the determination of facility beryllium sources is given.

Exposure-response analysis for beryllium sensitization and chronic beryllium disease among workers in a beryllium metal machining plant.

The current occupational exposure limit (OEL) for beryllium has been in place for more than 50 years and was believed to be protective against chronic beryllium disease (CBD) until studies in the 1990s identified beryllium sensitization (BeS) and subclinical CBD in the absence of physical symptoms. Inconsistent sampling and exposure assessment methodologies have often prevented the characterization of a clear exposure-response relationship for BeS and CBD. Industrial hygiene (3831 personal lapel and 616 general area samples) and health surveillance data from a beryllium machining facility provided an opportunity to reconstruct worker exposures prior to the ascertainment of BeS or the diagnosis of CBD. Airborne beryllium concentrations for different job titles were evaluated, historical trends of beryllium levels were compared for pre- and postengineering control measures, and mean and upper bound exposure estimates were developed for workers identified as beryllium sensitized or diagnosed with subclinical or clinical CBD. Five approaches were used to reconstruct historical exposures of each worker: industrial hygiene data were pooled by year, job title, era of engineering controls, and the complete work history (lifetime weighted average) prior to diagnosis. Results showed that exposure metrics based on shorter averaging times (i.e., year vs. complete work history) better represented the upper bound worker exposures that could have contributed to the development of BeS or CBD. Results showed that beryllium-sensitized and CBD workers were exposed to beryllium concentrations greater than 0.2 microg/m3 (95th percentile), and 90% were exposed to concentrations greater than 0.4 microg/m3 (95th percentile) within a given year of their work history. Based on this analysis, BeS and CBD generally occurred as a result of exposures greater than 0.4 microg/m3 and maintaining exposures below 0.2 microg/m3 95% of the time may prevent BeS and CBD in the workplace.

Introduction to beryllium: uses, regulatory history, and disease.

Beryllium is an ubiquitous element in the environment, and it has many commercial applications. Because of its strength, electrical and thermal conductivity, corrosion resistance, and nuclear properties, beryllium products are used in the aerospace, automotive, energy, medical, and electronics industries. What eventually came to be known as chronic beryllium disease (CBD) was first identified in the 1940s, when a cluster of cases was observed in workers from the fluorescent light industry. The U.S. Atomic Energy Commission recommended the first 8-hour occupational exposure limit (OEL) for beryllium of 2.0 microg/m3 in 1949, which was later reviewed and accepted by the American Conference of Governmental Industrial Hygienists (ACGIH), the American Industrial Hygiene Association (AIHA), the American National Standards Institute (ANSI), the Occupational Safety and Health Administration (OSHA), and the vast majority of countries and standard-setting bodies worldwide. The 2.0 microg/m3 standard has been in use by the beryllium industry for more than 50 years and has been considered adequate to protect workers against clinical CBD. Recently, improved diagnostic techniques, including immunological testing and safer bronchoscopy, have enhanced our ability to identify subclinical CBD cases that would have formerly remained unidentified. Some recent epidemiological studies have suggested that some workers may develop CBD at exposures less than 2.0 microg/m3. ACGIH is currently reevaluating the adequacy of the current 2.0 microg/m3 guideline, and a plethora of research initiatives are under way to provide a better understanding of the cause of CBD. The research is focusing on the risk factors and exposure metrics that could be associated with CBD, as well as on efforts to better characterize the natural history of CBD. There is growing evidence that particle size and chemical form may be important factors that influence the risk of developing CBD. These research efforts are expected to provide data that will help identify a scientifically based OEL that will protect workers against CBD.