230 likes | 477 Views
Biological agents: Need for Occupational Exposure Limits (OELs) and feasibility of OEL setting. Rafal Górny Department of Biohazards Institute of Occupational Medicine and Environmental Health WHO Collaborating Centre Sosnowiec Poland. Biological agents (BA) – is it a problem?.
E N D
Biological agents: Need for Occupational Exposure Limits (OELs) and feasibility of OEL setting Rafal Górny Department of Biohazards Institute of Occupational Medicine and Environmental Health WHO Collaborating Centre Sosnowiec Poland
Biological agents (BA) – is it a problem? Epidemiological studies: in world scale a few hundred million people are exposed to BA • Putting non-occupational indoor environment aside, exposure to BA is registered for 148 specialist work professional groups in 22 main branches of industry Important issue for occupational medicine and public health • Adverse health effects: allergic reactions, infections, toxic reactions, and nonspecific symptoms
Biological agents at work • bioaerosols - airborne transport of biological particles • penetration of biological agents through the skin, mucous membrane or with a bite of bloodsucker arthropoda • less frequently through the alimentary tract (such way is rather atypical for occupational infections) Conditio sine qua non of proper hygienic regime of occupational settings and health comfort is correct control of worker exposure and control of crucial parameters determining contamination of work environment by BA
Necessary needs Elaboration of widely accepted guidelines, standards or limit values enabling proper interpretation of environmental situations or measurement results, at least Evaluation criteria
Lack of standards/limit values • dose-response relationship is still indeterminate and controversial in many aspects • it is not possible to identify individual species of microorganisms or other specific BA responsiblefor health effects (except some common allergies attributed tospecific agents or exposure) • susceptibility as an individual feature of each organism • source data regarding environmental/occupational concentrations of biological agents are still insufficient • lack of standardization of sampling methods (lack of standard samplers) and experimental procedures (lack of commonly approved criteria for assessing exposure to biological agents)
Status quo ante Standards or limit values, if established, base on clinical picture of disease caused by biological agent, taking into account only presence of the reliable factor in some element of the studied environment (qualitative approach) Status praesens Nevertheless, quantitative standards, reference or limit values do exist to facilitate interpretation of measurement data
Strategy of hygienic standard elaboration 1. ENVIRONMENT INDOOR OUTDOOR DWELLINGS OCCUPATIONAL ENVIRONMENT NONINDUSTRIAL INDUSTRIAL 2. AIR SURFACES
Sampling method as immanent component of proposed standard/limit value To ensure the reliability of bioaerosol measurementmethods and their proper interpretation, in the first place, it is necessary to unify the methodology, i.e., to recommend the use of proper methods. The active air sampling (e.g., volumetric methods) should allow the measurement of a concentration of microorganisms and describe their taxonomical origin. Various technological and lifestyle recommendations and guidance allow to control the work environment contaminated with biological agents using a few different methods (e.g., „Recommended limits for microbiological monitoring of clean areas for sterile processing” according to the EU’s Good Manufacturing Practice (GMP) guideline)
Quantitative standard/limit value examples CULTURABLE OR VIABLE EVALUATION STANDARDS FOR HOME & COMMERICAL BUIDLINGSGovernmental Bodies1. Brazil2. Canadian Mortgage and Housing Company (CMHC)3. Commission of European Communities4. Czech Republic5. Finland6. Netherlands and Research Institute7.New York City Department of Health (NYCDH)8. Nordic Council9. Poland10. World Health Organization (WHO) Trade Associations Indoor Air Quality Standard11. American Conference of Governmental Industrial HygienistsTrade Associations12. American Industrial Hygiene Association13. Indoor Air Quality Association (AIHA)14. International Society of Indoor Air Quality and Climate (IAQA) TOTAL SPORE EVALUATION STANDARDS GOVERNMENTAL BODIES15. Russian Federation Standard16. Texas Department of Health Trade Associations (TDH) 17. American Academy of Allergy, Asthma & Immunology18. American College of Occupational and Environmental Medicine CULTURABLE OR VIABLE SPORE LIMITS FOR MEDICAL DEVICE & PHARMACEUTICAL CLEAM ROOMSGovernmental Bodies19. European Union Clean Room Standard20. U. S. Pharmacopoeia clean room standard
Quantitative standard/limit value examples Functional Grouping of Mold and Bacteria Standards A. Permissible or Acceptable Exposure Levels B. Action Levels (Warranting Investigation) C. Ceiling Limit or IDLH Levels (Immediately dangerous to life and health) D. Clearance Levels Exposure Guidelines (Post Remediation) E. The Inside Versus Outside Concentration Rank Order Guidelines F. Ceiling Limits for Hospitals & Other Susceptible Occupant Environments G. Bacteria Standards H. Application of the Standards - The Issue of Open Windows
Quantitative standard/limit value examples Total bacteria:1,0103 ÷ 7,0103 CFU/m3 for dwellings and non-occupational indoor environment as well as ≤7,5102 ÷ 1,0107 CFU/m3 for occupational environment (in all these indoor spaces no safe level for pathogens (0 CFU/m3) Gram-neg. bacteria:1,0103 ÷ 2,0104 CFU/m3 for occupational environment Endotoxins:0,005 ÷ 0,2 µg/m3 for occupational environment Total fungi:1,0101 ÷ 1,0104 CFU/m3 for dwellings and non-occupational indoor environment as well as<1,0102 ÷ 1,0107 CFU/m3 for occupational environment (in all these indoor spaces no safe level for pathogens (0 CFU/m3) Subtilisins:0,06 µg/m3 for occupational environment House dust allergens: miteDer p I: 2,0 ÷ <15,0 µg/g cat Fel d I: <1,0104 ng/g dog Can f I: <1,0105 ng/g
Quantitative standard/limit value examples Special environments, i.e., hospital premises and clean areas for sterile processing: 1,0100 ÷ 4,0103 CFU/m3and <1,0100 ÷ 1,0103 CFU/m3 Clean areas for sterile processing: the microbial quality of the air is accompanied by the control of a quality of the surfaces. The proposed limits are as follows: <1,0100 ÷ 4,0102 CFU/24 cm2, if concentration is related to the surface (usually equal to the surface of Petri dish), <1,0100 ÷ 2,0101 CFU/glow, if the certain quality of the worker hands is required, or 3,23105 CFU/m2, if microorganisms sediment on the surface within 1 week or up to 106 CFU/g of dust, if the concentration is related to the amount of settled dust
2000 Directive 2000/54/EC of the European Parliament and of the Council of 18 September 2000 on the protection of workers from risks related to exposure to biological agents at work. Defines employers’ obligations in terms of the protection of workers against risks to their health and safety, including the prevention of such risks, arising or likely to arise from exposure to biological agents at work Annex III – Community classification (the list of classified BA) Qualitative approach
„Life after... Directive 2000/54/EC” European standards (EN) – Workplace atmospheres: 13098: Guidelines for measurement of airborne micro-organisms and endotoxin 14031: Determination of airborne endotoxins 14042: Guide for the application and use of procedures for the assessment of exposure to chemical and biological agents 14583: Volumetric bioaerosol sampling devices – requirements and test methods German standards (VDI) – Measurements of airborne microorganisms and viruses in ambient air 4252: Active sampling of bioaerosols 4253: Culture based method for the determination of the concentrations of moulds in the air 4255: Bioaerosols and biological agents - Source of emissions and control measures - Overview No way of interpretation of quantitative results is given
2004 Establishment of Biological Agents Expert Group as a part of the Interdepartmental Commission for Maximum Admissible Concentrations and Intensities for Agents Harmful to Health in the Working Environment Central Institute for Labor Protection - NRI Warsaw, Poland
Biological Agents Expert Group Scientific approach If a solid link between the concentration of investigated parameters and resulting adverse health effect cannot be effectively established, then, based on the biological agent concentration measurements, the reference values should enable evaluation of the quality of the environment, as well as determination of “what is typical and acceptable” and “what is atypical or not acceptable”for a specific type of setting
Polish proposals for OEL and PSLV/RLV for bioaerosols (volumetric methods) *)For respirable fraction the proposed limits should be twice as low, i.e., 50000 CFU/m3 for total mesophilic bacteria, 10000 CFU/m3 for both Gram- negative bacteria and thermophilic actinomycetes, and 25000 CFU/m3 for fungi
Decision making when standards/limit values are not available • Understanding of the nature of phenomenon and adequate measurement of biological agent (usually in the air) • Understanding and defining of health effects as a result of such exposure • Elaboration of the real hypothesis, which should be tested