Document Ed7NkM4Y8qdB8jzLxNYN0Z9x0

X$21 B. Strokova S. Evstatieva S. Dimitrova E. Mavrodieva R. Lukanova Study of asbestos exposure in some applications Springer-Verlag 1998 Abstract This study is designed to determine the effects Key words Asbestos analysis - Asbestos chemistry X;; of short-term asbestos exposure On workers in the produce Air pollutants Environmental analysis Environmental tion of asbestos gaskets and filter materials for technolog pollutants 'f-:j!:' ical equipment in the chemical industry. The y/orkers from the ``Cathode workshop", "Diaphragin electrolysis",. -t-;---"; ;;;Ii>eViy stallation of asbestos diaphragms; manufacture andlnstal- lation of electrolysis cells, aridithe staff of the "Mechani Several properties found in asbestos materials make them cal" shop of "Nephtochim" Co., Burgas, engaged in the cut? valuable for use in chemical productibn* i.e,, high resis titig Of gaskets made Of pressed asbestos -polymer boards tance to aggressive agents, stability at high temperatures (6 workers), were studied. Hie hygienic normative standards and pressures, non-combustion, insulation and filtration and methodology for measuring and assessment of the as features. The following products: chrysotile, asbestos-tex bestos exposure, used all over the world were applied: tile products, pressed asbestos-polymer components, as mean bestos bands with Teflon coating etc. are used in the man bres; entire shift personal sampling (13SS;2200^85), PCOM ufacture of fittings, couplings; insulation's for apparatuses light microscopy (BSS 16909^9), ^Pisvel^ and vessels for water steam, acetylene, solvents arid other Ifrolysis-dte;.-: XXX;XxX;>f X The production metiiodg for irtechanidaf^ ffeni^ 3she est^shidicShe^^^^t^lie/ ting, polishing) and the consequent change of the product acceptable according to the requirements of the official hy are accompanied by the release of asbestos fibers, for gienic threshold limit value (TTJLV) in Bulgaria (1 f/cm3), but because asbestos is a human cancerogen and there is been proved. In the chemical industry, dust removal oper tendency for regular revision with the ihtehtiph of decreas> ations are usually short-term (less than 3 h per working shift, ' " ' .................. . ..... . statements made increase the hecessity of dust cbhtref by; , identified as a risk. ^ t ---> it.. .systemiin'BulgariaX; ,:X; ;; X; '/X: '1r!V;X';;';XrXXX;XXXXx ' Work presented at the 25th Congress on Occupatipnsil aiid Environ mental Health In the Chemical Industry (lyleaichem 1997) "Global Challenges to Occupational and Environmental Health in the Chemical Industry", 30 September-3 October 1997, Vama,-Bulgaria ' , ` ' XX - ,' V, . X'Xv'-'XXvX \XX X.. OCCU pational asbestos risk and the fact that there is no alterna tive safer material that can;be used. X:XXX:X- ; X XXxXX JB. Strokova (ES3) S. Evstatieva S. Dimitrova E. Mavrodieva ; k. Lukanova \-v. v ./ .v--~ Laboratory "Chemical factors of the work environment and dust", National Centre of Hygiene, Medical Ecology and Nutrition, X; v :15 "i5."Ne$torov" Blvd, 1431 Sofia, Bulgaria Fax: (359 2) 95 81 277 ji Aim of the study The study i emission of asbestos dust in the ambient air during^pro- S20 Table 1 Results from the determination of the asbestos fibres concentration Enterprise Polymers Ltd Polymers Ltd Polymers Ltd Neftochim Ltd Neftochim Ltd Technological operation Dosage and teaselling of asbestos Assembly of an electrolysis cell Cleaning of an asbestos warehouse Cutting findings Cutting of asbestos ropes Concentration (C) of fine as bestos fibers f/cm3 0.38 Asbestos content in total dust (%) 1.5 <0.1 - 0.14 1.5 0.43 <0.1 4 - Hygienic assessment K* 0.38 <0.1 1.4 0.43 <0.1 duction manipulations with asbestos products in the chem ical industry. Study design and methods mination of the asbestos content in the dust of the air and its con centration in the emission, the infrared spectrometric gravimetric method was used [10]. The study was carried out in the "Chemical factors of the worl environment and dust" laboratory in the National Centre of Hygiene Medical Ecology and Nutrition, Sofia in 1996. In this study, workers in contact with asbestos from two chemical factories ("Polymers" Ltd., Devnja and "Neftochim" Ltd., Burgas) are included, as well as the organized emission sources as follows: Results 1. In the "Diaphragm electrolysis", Department, "Polymers" Ltd, Devnja, 12 operators from the "Cathodes" workshop, engaged in the production of asbestos diaphragms made of chrysotile asbestos material, were studied as well as those engaged in the installation of electrolysis cells and the organized emission source. The work ing procedures involving asbestos (teaseling, weighting) were per formed automatically in a special installation, that provided reli able ventilation and filtration of the released air. Only the packag ing of the material was carried out manually. Suction cleaning of the dust, deposited on the floor of the warehouse and work premises, was stipulated. The workers were provided with per sonal protective equipment for respiratory organs. 2. In "Neftochim" Ltd, Burgas, 6 cutters from the "Mechanical" department who were engaged in cutting out at band-saws fittings made of pressed asbestos-polymer boards, were studied. The processes performed by the use of universal drilling machines in partitioned areas in the Mechanical Department without local ven tilation. The workers were provided with suitable personal protec tion equipment for respiratory organs. Dust deposited on the floor was wetted when cleaned, and the waste was packed in polyethyl ene bags for storage on landfill sites. Measurements were taken of the average shift concentration of as bestos dust in the breathing zone of the operators in both processes and of the emissions from the organized source at the machine for teaseling the asbestos in "Polymers" Ltd, Devnja, during the pe riod of 1 to 2 working shifts. The sampling was performed observ ing all requirements of BSS 2200-85 [2], BSS 16909-89 [3], BSS 172402-78 [4] and EN 689/1995 [5], Personal and stationary dust sampling devices of "Highest" and "Guilian" types were used. For the assessment of asbestos exposure, the standard parameter generally accepted all over the world [6] and in Bulgaria was ap plied: average shift count concentration of respirable asbestos fibers (with diameter (d) < 3 pm, lengths (1) > 5 pm and aspect ratio 1/d > 3) with the threshold limit value (TLV) in Bulgaria 1 fiber/cm3 [7] and action level - 0.2 f/cm3 according to CD 91/382/EEC [8], The asbestos emission is evaluated according to the index "mass fiber concentration" with TLV 0.1 mg/m3 [9], The determination of the count concentration of asbestos fibers is performed by microscopic method, according to BSS 16909-89 [3], using a "Reichert" microscope with a magnification of 600 times. In addition to the asbestos count concentration, the content of mass in the air of the work environment was studied. For the deter The results from the study (Table 1) show the presence ol asbestos pollution in the air of the working environmeni and emissions from the manufactures studied. The asbestos content in the dust in conditions of dusi protection of the asbestos - machine (at teaseling the as bestos material) in "Polymers" Ltd, Devnja was reduced to 1.5%. In the working places without purification sys tems in "Neftochim" Ltd (cutting out the asbestos-poly mer sheets) it was relatively higher at 4%. The occupational asbestos exposure of the staff in both sites was acceptable in complying with the acting TLV in Bulgaria (below 0.5 TLV) but cannot be considered safe according to the stricter requirements of the EC Directives [6, 8]. For the operators of asbestos-machinery in "Poly mers" Ltd and the cutters of asbestos-polymer boards in "Neftochim" the action level [8] is exceeded twice, im posing the need for additional measures for dust protec tion and prevention. The content of fine asbestos fibers in the emissions from the organized source in "Polymers" Ltd is about 0.1 TLV. Conclusions The results of the study of the dust factor, related to the use of asbestos items in the petroleum-chemical and poly mer production industries show the presence of accept able levels according to the acting national standards for asbestos pollution in the work environment air and in the emissions from the organized source. The level of asbestos exposure of the workers is below 0.5 TLV, which cannot be considered absolutely safe, par ticularly as the proved carcinogenicity of asbestos dust and the world trend to the revision and reduction of the threshold limit values. In the particular productions the following additional technical-prevention measures for dust removal fxom the operations with asbestos materials must be undertaken: (a) using local suction devices at filtration of the output |tir in "Neftochim", Ltd for the cutting of asbestos-polyer sheets; (b) implementation of suction cleaning of the Bust deposited on the floor and on the uncovered ma chines surfaces in "Neftochim", Ltd; (c) automation of cutting of the asbestos material when producing asbestos diaphragms in "Polymers", Ltd. These findings recommend the implementation of hy gienic controls of asbestos dust for such activities and medical check-ups for those workers exposed. References 1. Ordinance N 12/1993 of the Ministry of Health for sanitary regulations at import, manufacture and use of asbestos and as bestos-containing materials and products. State Gazette no 98/ 1993 S21 2. BSS 2200-85 Hazardous substances in the air of the working environment. Methods for determination of dust concentration 3. BSS 16909-89 Hazardous substances in the air of the working environment. Determination of the count concentration of as bestos fibers in mixed asbestos-containing dust 4. BSS 172402-78 Environmental protection. Ambient air. In dices of emissions quality. Method for determination of dust content 5. EN 689/1995 Workplace atmospheres. Guidance for assessment of exposure by inhalation to chemical agents for comparison with limit values and measurement strategy 6. Council Directive 83/477/EEC on the protection of workers from the risks related to exposure to asbestos at work 7. Ordinance N13/1992 of the Ministry of Health for TLV of haz ardous substances in the air of the working environment. State Gazette No. 81/1992 8. Council Directive 91/382/EEC amending Directive 83/477/EEC on the protection of workers from the risks related to exposure to asbestos at work 9. Standards for admissible emissions (concentrations of waste gases) of hazardous substances emitted in the atmosphere. Min istry of Environment, State Gazette, No. 81/1991 10. Methodical guidance for sampling strategy. In: Regulations for work hygiene, Ministry of Health, Meditzina i fizkultura, Sofia, 1983, vol II, 221