[Occupational hygiene in industrial assembly work]. / Khigiena na truda pri promishleno-montazhna deinost.

Data on occupational hygienic characteristics of industrial-assembly work are reported, which have not been subject upto now to such studies. Complex hygienic evaluation of the basic physical and chemical factors of the working environment is performed as well as physiological and ergonomic characteristics of the principle professional groups, analysis of the occupational diseases and diseases with temporary disability and clinic and laboratory examinations on the workers. The following peculiarities of occupational hygienic aspect are established: 1. dynamic and multiform professional itinerary of the industrial-installing workers; 2. large variability in the characteristics of the physical and chemical factors of the working environment, most frequently surpassing the admissible norms and requirements, as well as the duration of exposure to them; 3. considerable working engagement (from 63 to 78% operation time), connected with heavy physical loading (dynamic and static), exceptionally unfavourable, compulsory and fixed working posture, possibilities of prolonged working day, high rate of involvement of the psychomotor sphere, analyzers and attention, great professional responsibility and nervous and emotional stress; 4. occupational and general morbidity of workers, adequate to the already established by the authors occupational noxa--acute poisoning with smoking gases, injury of the hearing, diseases as a result of overpressure of the locomotor apparatus and the nervous system.

[Evaluation of the immune status of pupils of the Secondary Vocational-Technical School of Rubber and Plastics]. / Otsenka na imunnia status na uchenitsi ot SPTU po kauchuk i plastmasi.

Children of a Secondary Polytechnical school of rubber and plastics were studied. The task aimed at tracing the immunological reactivity of the young generation in the conditions of the chemical industry. The following methods were used: reaction for reactivity of the neutrophylic leucocytes, defining of hemoglobins G, M, E, establishing the complement in serum, the skin autoflora condition, assessment of the microbic saliva content. No significant deviation, expressing decrease of the immunologic reactivity of the organism of the schoolchildren during their training in industrial conditions were established.

[Determination of the mean length-of-service and mean daily exposure to lead of workers in battery manufacture]. / Opredeliane na srednostazhovata i srednodnevnata ekspozitsiia na olovo za rabotnitsi ot akumulatornoto proizvodstvo.

The determination of the occupational risk at the working places by only comparing the lead concentrations determined in the air of the working environment and MAC is not sufficiently complete, if consideration is not given to the length of service of the workers in contact with that metal. The determination of the mean daily exposure is of great significance in that case as well as the number of the days during which the workers had been exposed to the noxious effect of lead. That is why, the application of the method of A. Kovacev et al., allowed the determination of the mean-length-of-service and mean daily exposure to lead of the workers from some leading occupations from an accumulator plant, being the base for prognostication of the personal risk number and the allowable length of service for the newly come to work workers in the respective accumulator production.

[Natural immunity of the pupils in a secondary vocational and technical school for rubber and plastics]. / Sustoianie na estestveniia imunitet pri uchenitsi ot SPTU po kauchuk i plastmasi.

In connection with the reconstruction of the educational system and occupational training of the youths, the problem of the effect of the occupational factors on the organism of the juveniles is of exceptional importance. The search of early changes by the application of immunological tests in that aspect is very rational. The state of microflora of the deep layers of the skin, the microbic contamination of nasal mucosa have been studied as well as the content of complement in serum and serum immunoglobulins G, A and M and the phagocytosis in the students from SPTS. The experimental subjects have exposed to a complex of toxic-chemical substances with different intensity during their occupational training and practice. It has been established that the training under the specific conditions for mastering the specialty has led to a slight decrease of the antimicrobic resistance and reduction of the phagocytic function of leukocytes, not affecting the humoral factors of natural immunity.

[Assessment of the occupational risk to workers engaged in the manufacture of divinyl-styrene rubber]. / Otseniavane profesionalniia risk na rabotnitsi, zaeti v proizvodstvoto na divinil-stirolov kauchuk.

The production of synthetic rubber, one of the varieties of petro-chemical branch in our country, is new and very prospective. The Bulgarian synthetic rubber is synthesized from petroleum products divinyl and styrene. After the hygienic assessment of the technological processes, a complete characteristic of labour conditions was made and the character of the working process was studied of the main occupations of the workers, attending the installations of Synthetic Rubber Plant. The exposure to occupational noxae was determined and the existing occupational risk was evaluated. The toxico-chemical substances, benzene, styrene and divenyl, are with the highest significance among the factors of the working environment. The data on the health state of the workers are reported and recommendations are proposed for the restriction of the effect of the occupational factors.

[Industrial hygiene studies in the production of various fibers and plastics]. / Trudovokhigienni izsledvaniia v proizvodstvoto na niakoi vlakna i plastmasi.

The results from the labour-hygienic and clinical laboratory studies on working environment and workers engaged in production of polyamide (PAS) and polyacrylnitrile fibres (PAN) are summed up as well as in the production and processing of polyvinylchloride resin, polyurethan, polysterene and glass fibre laminates. The main deleterious factors in those productions are the chemical ones: caprolactam, acrylonitrile,tolyl diisocyanate, vinylchloride, styrene, etc. Noise and microclimate are the other unfavourable on-the-job factors. The concentrations of the toxic substances in the air of the working environment are pointed to be far over MAC, in spite of the new plants. Experiments are reported aiming at the determination of the real exposure of the workers - via individual sample collecting and elaboration of BMAC. The measures for the improvement of the conditions of the working environment in the production of synthetic fibres and plastics are summed up as well as the reduction of occupation risk of the workers.

[Effect of dimethylformamide on the health status of workers]. / Vliianie na dimetilformamida vurkhu zdravoslovnoto sustoianie na rabotnitsi.

Results are reported of the clinical examination and some laboratory tests performed in a group of workers, employed in the production of polyacrylnitryl fibers "Bulana" at the oil- processing and chemical works in Burgas, who have been exposed for 3 to 5 years to dimethylformamide (DMF). DMF concentrations in the air of the work environment were within the threshold ones, or exceeded them from 3 to 6 times. The most common constitutional symptoms were: fatigue, weakness, numbness of the extremities, eye and throat irritation. The results of physical examination were comparatively scanty. In spite of careful search, liver function and hemopoiesis were normal, neither were significant arterial pressure variations observed. These data will be used as baseline for comparison in a furture study of the technological staff, working in contact with DMF.