Occupational Health - Public Health Poster Session
Acryl compounds are various chemicals within a large group. They are used in medicine and household. Acryl compounds are: acryl acid, methacryl acid (MAA); their derivates (ethers, amides, nitriles and others); polymers and co-polymers on their base. Until now there was a few studies on occupational medicine problems arising at acryl compounds manufacture. These studies did not reflect all the importance of the problem.
Materials and Methods
Nizhny Novgorod Research Institute of Hygiene and Occupational Pathology performed prolonged integrated investigations of the problem during many years. Total evaluation of these investigations was made. Investigation included toxicity evaluation of acryl compounds and chemicals (about 40) used at their synthesis; working conditions at 24 plants; state of health of 1192 workers and reproductive function of 1500 female workers; difficulty and intensity of labour in 258 operators in manufacture of organic polymer glass, MMA, methyl- and butyl acrylate (MA, BA), polymethyl methacrylate (PMMA). Generally accepted methods were used for the investigations.
It was established that workplace air at acryl monomers producing plants was polluted by mixture of chemicals, mainly with acryl and methacryl acids or their ethers and alcohols (methyl and butyl alcohols). Simultaneously vapors of cyanides (hydrocyanic acid, aceto- and ethylencyanohydrins, acrylonitrile), acrolein, aerosol of sulfuric acid and others were found at the same workplaces, it depended on acryl monomer producing technique. The highest level of ethers concentration was found at MMA producing plants, but at MA producing shops this level was lower. Methanol was found more often and in higher concentrations than butyl alcohol. The lowest level of ethers and butyl alcohol vapor was found at plants producing less volatile BA and buthyl methacrylate (BMA). Main occupational hazard was exposure to monomers in departments where acryl polymers and co-polymers were produced. MMA air concentrations often were 3-10 times higher than maximum allowable concentration (MAC) at organic polymer glass shops, especially in moulding and polymer preparation departments. There were lower concentrations of monomers vapors (MMA, BMA, MAA, BA, MA) (as a rule at MAC level) at plant where had produced PMMA suspension, emulsions, polybuthyl methacrylate (PBMA), dacryl, methaclyl co-polymers and industrial goods of PMMA. It is possible that air is polluted by polymer dust at final stages of polymers producting.
Main causes of work environment pollution are the following: insufficient hermeticity of equipetment due to technical imperfection and corrosive properties of organic acids and other chemicals; manual work; low effectiveness of local ventilation; high pressure and high temperature in apparatuses; opening of apparatuses for cleaning from polymers masses formed by spontaneous polymerization.
Accompanying unfavourable occupational factors were high temperature (27-40 centigrade), intensive noise (up to 92-98 dBA) at some workplace. Labor of operators at automatized and mechanized MMA, BA, and MA producing plants is classified as "light, non-intensive"; labor of most workers groups at organic polymer glass producing plants is classified as "middle heavy". These data show that workers at studied plants as a rule were intermittently exposed to hazardous chemicals mixture in combination with high temperature and noise at some workplaces. To evaluate working conditions influence on workers' health, it should taken into consideration not only chemicals exposure level, but also various biological effects of the chemicals and degree of their toxicity. Monoethers of MAA are typical substances with mainly narcotic effect and slight irritant properties. Ethers of acrylic acid (AA) possess general toxic and irritant properties. Following regularities were revealed: increasing of absolute toxicity; decreasing of potential danger and local irritant effect by increasing of atom number alcohol radicals in AA and MAA monoethers; increasing of toxicity, irritant and general toxic effect by increasing of saturation degree in AA ethers as compared with MAA ethers. Established dependencies of quantitative biological effect on (meth)acrylates chemical structure let to predict toxicity of newly synthesized acryl compounds and to increase the reliability of their non-dangerous levels. Gonadotropic and embryotoxic effects of some (meth)acrylates at high and low doses and concentration were revealed in experiments on animals . Workplace air MACs for more than 30 acryl monomers and chemicals used for their synthesis were establised on the base of toxicological, hygienic and clinical studies data. Atmospheric air MACs and water MACs for these chemicals were also established .
Most of the studied polymers and co-polymers on the base of acryl and methacryl monomers are considered as "slightly toxic" compounds. As a rule poly(meth)acrylates dust do not possess fibroplastic effect. Workplace air MAC = 10 mg/m3 was established for this group of chemicals.
By deepen health condition investigation some functional disturbances of nerve and cardiovascular systems were revealed in persons worked at methylacrylate, acryl emulsions and suspension PMMA producing plants. For the first time chronic occupational intoxication by MMA was revealed in workers exposed during a long period (6-20 years) to high concentrations at MMA and organic polymer glass producing shops. The disease clinical manifestations are combination of vegetative-vascular dystonia, asthenic-neurotic or asthenic-organic syndrome and vegetative-sensitive polyneuropathy [1, 3]. Occupational dermatoses can be found in workers exposed to MA and other chemicals by using poly(meth)acrylates.
Disturbances of menses, gestation, delivery were in 1.5-3.3 times higher in operator-women exposed to MMA, than in contol women (differences were statistically significant). There were not statistically significant differences in newborn health conditions, physical and neuropsychic development of children of women-workers as compared with control group.
Discussion and Conclusion
Analysis of obtained data provided evidence that the most important hygienic problem is hazardous chemicals exposure at high concentrations, especially volatile substances MMA, MA and BA. Found concentrations presented certain danger to workers' health. Long time exposure to acryl monomers, especially MMA, at high concentrations can evoke various pathological changes in human body and lead to chronic occupational diseases.
Integrated approach to solution the problems of occupational medicine arising at acryl compounds producing lets to establish and elaborate principal ways for creating more safe working conditions and preventing occupational diseases in workers exposed to these chemicals. Fulfilment of sanitary and medico-biological measures promoted to considerable decreasing of hazardous chemicals concentrations in air, abrupt decreasing of occupational diseases and reproductive health improvement of women workers.
1. Blagodatin VM, Golova IA, Blagodatkina NK et al. Industrial hygiene and occupational diseases in the production of organic glass. Gig Tr Prof Zabol 1970; 14(8):11-4.
2. Blagodatin VM, Smirnova ES, Dorofeeva ED et al. Establishing the maximum permissible concentration of methyl ester of methacrylic acid in the air of work area. Gig Tr Prof Zabol 1976; (6):5-8.
3. Sharova TG, Fedotova IV, Dorofeeva ED, Blagodatin VM Development, course and late sequelae of diseases in workers engaged in organic glass production. Med Tr Prom Ekol 1993;(9-10):8-10.
4. Smirnova ES, Blagodatin VM Effect of the methyl ester of methacrylic acid in small concentrations on sexual function of white rats Gig Tr Prof Zabol 1977; (2):49-51.
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|Blagodatin, VM; (1998). Problems of Occupational Medicine in Acryl Compounds Production.. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/occupational/blagodatin0737/index.html|
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