Beryllium Exposure Assessment: Review of Sampling and Analytical Developments and Impending U.S. Regulatory Changes

Transcription

1 Beryllium Exposure Assessment: Review of Sampling and Analytical Developments and Impending U.S. Regulatory Changes Michael J. Brisson, Savannah River National Laboratory, Aiken, SC, USA Gary E. Whitney, Los Alamos National Laboratory, Los Alamos, NM, USA Kevin Ashley, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Cincinnati, OH, USA Chemical Risk: Innovative Methods and Techniques 9 April 2015, Nancy, France SRNL-MS S

2 Disclaimers The findings and conclusions in this presentation are those of the authors and do not necessarily reflect the views of DOE, SRNL, LANL, or CDC/NIOSH Mention of commercial products or companies does not imply endorsement or criticism. Nothing in this presentation is intended, nor should it be construed, to represent restraint of trade. 2

3 Beryllium Properties Light weight High melting point (1287 o C) High heat capacity Neutron reflector Relatively transparent to X-rays High-fired BeO: Thermally conductive Electrical insulator SEM of calcinedbeoparticles, by J. Fernback (from Goldcamp et al., JOEH 2009) 3

4 Uses for Beryllium Products Satellites / spacecraft Guidance systems (military & commercial) Brake parts (automotive, aircraft) Nuclear weapons (neutron reflector) X-ray windows Optical instruments High-end audio Sports equipment Alloys (Al-Be, Cu-Be) resistant to corrosion and/or metal fatigue Electronics micro-circuitry (CuBe alloy; 4

5 Risks from Beryllium Exposure Exposure to particles of beryllium metal, alloys, and oxide can lead to: Beryllium Sensitization (BeS) Immune system response in percentage of those exposed Detected by Be Lymphocyte Proliferation Test (BeLPT) Chronic Beryllium Disease (CBD) Percentage of sensitized individuals Particles lodged in lung, cannot be expelled Causes lesions (granulomas) Medically diagnosed (bronchioalveolar lavage) Treatable but not curable (schematic from G. Day et al., 2007) 5

6 Current Occupational Exposure Limits (Values in micrograms per cubic meter) 2.0 (Current OSHA PEL used by 11 other countries) 1.0 (Denmark, Latvia) 0.5 (NIOSH REL) 0.2 (DOE AL; also Cal- OSHA, Poland, Spain-INH) 0.15 (Quebec) 0.05 (ACGIH TLV, inhalable fraction) Zero (everyone wants it but lab can t measure it) OSHA U.S. Occupational Safety and Health Administration PEL Permissible Exposure Limit NIOSH U.S. National Institute for Occupational Safety and Health REL Recommended Exposure Limit AL Action Level INH Inhalable Fraction TLV Threshold Limit Value Germany has been studying its Be OEL, which may be reduced (Nies, 2012). DOE also has a surface contamination limit (0.2 µg per 100 cm 2 ) 6

7 Potential Changes to U.S. Regulations OSHA Permissible Exposure Limit Expected: lower PEL, short-term exposure limit (STEL), housekeeping and PPE requirements Considered current DOE regulation & stakeholder input Notice of Proposed Rulemaking expected soon (this year) DOE Chronic Beryllium Disease Prevention Program (10 CFR 850) Currently uses OSHA PEL and is expected to continue doing so Some aspects of OSHA regulation (such as STEL) do not currently apply; this might change under new DOE proposal Airborne OEL may be lowered significantly, perhaps to ACGIH TLV Notice of Proposed Rulemaking not likely before late 2015 Potential Impacts Some U.S. industries outside of DOE will need to take steps to reduce airborne Be In DOE, the same may be true at some locations since oversight typically requires adherence to levels below OSHA PEL Labs likely to need ICP-MS or fluorescence, especially for short-term samples, because ICP-AES may not offer sufficient detection limits Other impacts to be determined when new proposed regulations are published 7

8 Short-term air monitoring Sampling considerations: For a 15-minute task, a 2 L/min pump provides 30 L or 0.03 m 3 In this case, lab must be able to detect 3% of the exposure limit If proposed OSHA STEL is used, this would be 2 µg/m 3 x 3% = 0.06 µg per sample Analytical considerations: Ideally MDL is a factor of ten below OEL to assure that measured result, including analytical uncertainty, is quantifiable at the OEL Analytical method should provide MDL of µg per sample or less High-flow sampler could help to ameliorate these constraints 8

9 Sampling for Inhalable Fraction ACGIH TLV specifies inhalable fraction Current IOM inhalable sampler not disposable Higher cost than disposable closed-face cassettes Requires cleaning between uses (time consuming and costly) Insert capsules for IOM under development Study to develop disposable sampler to collect inhalable fraction (Volckens, Sleeth & Anthony, Airmon 2014) Goal: low-cost personal samplers for inhalable aerosols 9

10 Combine attributes of the CFC with the IOM Inhalable Aerosol Sampler (courtesy of Profs. J. Volckens, D. Sleeth& R. Anthony) IOM-style Inlet Capsule filter CFC-style cartridge Want a sampling apparatus that is: Inexpensive Disposable User friendly Physiologically relevant 10

11 Sampler inserts (to account for wall deposits) Polyvinyl chloride (PVC) insert with PVC filter in a 37-mm CFC Commercially available Suitable for gravimetric analysis Not appropriate for elemental analysis Acid-soluble cellulose acetate insert with mixed cellulose acetate (MCE) filter Commercially available Incorporated improvements suggested by Ashley and Harper (2012, 2013) Not appropriate for gravimetric analysis due to mass variability with humidity changes Solu-Cap insert: skcinc.com NIOSH studies have validated gravimetric and elemental analysis using cassette inserts Inserts for IOM samplers also available soon Solu-Sert inserts: zefon.com 11

12 Analytical Advancements Fluorescence Method (McCleskey et al., 2005; Agrawal et al., 2006; Ashley et al., 2007; Ashley, 2011) N OH Interlaboratory Evaluation of ICP-MS (Ashley et al., 2009, 2012) Beryllium Dissolution Studies (Goldcamp et al., 2009; Oatts et al., 2012) HBQS fluorophore SO 3 H Direct-measurement techniques (e.g., LIBS) Fluorescence and ICP-MS methods yield MDLs in sub-ng per sample range; also consider ETAAS Refractory BeO sample prep info used for methods updates ICP-MS plasma 12

13 Fluorescence Method for Ultra-trace Beryllium Measurement (Courtesy of Dr. A. Agrawal, Berylliant, Inc.) 1. Sample Automated high-throughput system Addition of dye soln Be extraction Fluorescence detection Removal of aliquot Filtration BeFinder Portable Fluorometer

14 Be dissolution studies (Oatts et al., 2012; Ashley et al., 2007; Goldcamp et al., 2009) Tested a variety of dissolution methods involving combinations of acids (e.g., HF, H 2 SO 4, HCl, HNO 3, HCl0 4, NH 4 HF 2 ) Focused on dissolution of BeO as refractory compound typically seen by IH labs Concluded that fluoride or sulfate ions required for effective BeO dissolution Individual lab recoveries ± std. devs. 150% 125% Recovery (%) 100% 75% 50% 25% H 2 SO 4 group NH 4 HF 2 group HF group HNO 3 group From Oattset al., J. Environ. Monit.(2012) 0% Lab ID # 14

15 Dermal Be Exposure and Sampling Potential risk from dermal exposure known for some time (Day et al., 2006) Nicas et al. (2008) indicated that: Workers made hand to face content an average of 16 times per hour (but variable, ranging from 1 to 35 contacts per hour) Contamination on the hands may be a point source for inhalation exposure when the hands are moved to the face. Whitney (2014) suggested that: Hand to face contact may contribute significantly to inhalation exposure and deserves further investigation. Gloves may protect skin, but may actually increase risk of contamination spread: Workers feel protected, so they may be less cautious about handling contaminated materials. Some loss of dexterity and tactical sensation may result in clumsier hand movements that spread contamination. Sampling the surface of gloves/hands at various points in an operation may aid in identifying sources of contamination spread & exposure routes. 15

16 Summary Recent sampling advances have focused on low-cost inhalable sampling and CFC inserts to reduce wall deposits CFC inserts are commercially available Soluble inserts also available soon for inhalable (IOM) samplers Beryllium-specific analytical advancements Fluorescence, ICP-MS (& ETAAS) suitable for ultra-trace Be determination Direct-reading capability shows promise but needs study Ability to distinguish among Be metal, alloys, and oxide desirable but needs study Dermal contamination on hands may be a vector for inhalation, and needs further study Dermal sampling of hands could be of value (new ASTM standard) Germany and U.S. are considering lower beryllium exposure limits Proposed changes in U.S. regulations are expected later this year Impacts of these changes to be determined, and could be significant 16

17 Contact Information Mike Brisson, SRNL, phone Kevin Ashley, CDC/NIOSH, phone Gary Whitney, LANL, phone Beryllium Health and Safety Committee web site: 17