[A chemical hygiene assessment of point emitters and of an unorganized source of air pollution from copper smelting at Nipkitoks in the city of Pernik]. / Khimiko-khigienna otsenka na tochkov emitor i neorganiziran iztochnik na zamursiavane na vuzdukha pri pretopiavane na med v ETD "NIPKITOKS" OOD--gr. Pernik.

Concentrations of adverse substances in air emissions of a copper manufacture have been determined. There have been found out dust, soot, copper, tin, lead. The generated emissions of these toxic elements from the investigated point generator are not above the admissible ranges and the established technologic conditions are not problematic. The concentrations of vinilchloride, carbon monoxide and carbon dioxide in the air of the working environment are below the respective admissible concentrations and the manufacture is not a source of pollution for the environment.

[A membrane filter sampling method for determining microbial air pollution]. / Membranno-filturen probovzemen metod za opredeliane na mikrobnoto zamursiavane na vuzdukha.

The method is a contribution in the evaluation of the exposition and the control of the standards for organic powders. The method concerns the sample-taking procedure and the analysis-making technique for determining of the concentration of the microbial pollution of the air. It is based on filtering of some amount of air through a membrane filter which is then processed for cultivating of microbial colonies on its surface. The results are obtained in number of microbial colonies per unit of air. The method presents opportunity to select and vary the filtered volume of air, to determine the respirable fraction, to determine the personal exposition, as well as for the simultaneous determining of the microbial pollution together with other important parameters of the particle pollutants of the air (metal, fibre and others).

[The assessment of the occupational risk to workers in electric steel production]. / Otsenka na professionalniia risk na rabotnitsite ot elektrostomanodobiva.

These studies, centering on occupational environmental factors, biologic monitoring, and toxicodynamic investigations, involved a total of 105 workers distributed into eight job groups, who were 45 years, of age on the average and had from 5 to 10 years of special occupational experience at "Electrosteel" Works. Evidence was obtained for presence of unfavorable microclimate conditions, elevated equivalent levels of noise, excess of general and local vibrations, exposure to manganese aerosols, carbon monoxide, and nitrogen oxides; some of the subjects and deviations in hepatic status and connective tissue. Job groups found to be at risk were those of steel founders, crane workers, and pourers.

[Comparative studies of personal and steady-state sampling for determining dust exposure in different job groups]. / Sravnitelni izsledvaniia na personalnoto i statsionarnoto probovzemane za opredeliane na prakhovata ekspozitsiia na razlichni profesionalni grupi.

The variability of the dust concentration in time and space, as well as the change of worker's place during the working process, define the necessity of introducing personal sampling in the hygiene control practice. However, the laboratory equipment with personal devices is still not sufficient. The aim of this work is to assess the dust exposure of the basic professional groups from the ore- and coal production in Bulgaria by personal sampling in comparative studies of the static ambient sampling used up to now. 63 full-shift investigations of the dust factor were performed on professional groups of miners of the polymetal and coal pits by static ambient devices-[Hygitest production] and personal [from firms "Casella", "Strolein" and "Gilian"] devices, after standardized methods. The results are data processed-by means of logarithmic normal distribution of the relation of the respirable dust concentrations, determined personally and by static ambient sampling. The limits of variation of this correlation are from 0.5 to 4.1 at average geometric value -0.95 and standard geometric deviation-1.8 i.e. both types of sampling are intersubstitutional for the examined groups and sites, as in the underground ores the professional risk of respirable dust is underestimated up to 4 times at static ambient sampling.

[Dust levels and dust-induced diseases in the main dust-producing industries]. / Zaprashenost i prakhovi zaboliavaniia v osnovnite prakhoobrazuvashti proizvodstva.

The data on airborne dust and occupational disease in the main dust-related industries of the People's Republic of Bulgaria are generalized and analyzed for a period of 15 years. In the ore producing industry is established a stability in the concentration of total and respirable dust 1-2 TWA concentrations and decrease of silica content in dust. The highest occupational hazard is registered in diggers. The levels of TWA total and respirable dust and silica concentrations in the other underground mines as well as in the overground industries are strongly variable and high. Silicosis is still in the first place among dust-related diseases, but mainly among miners of advanced age. The newly detected other pneumoconiosis, asbestosis, mixed pneumoconiosis are already more than the cases of silicotuberculosis. An essential part is taken by the newly detected diffusive pneumosclerosis and dust bronchitis. The distribution of the newly detected occupational lung diseases is studied according to branches of industry.

[Hygienic evaluation and the effects of toxic factors in the work environment of copper-processing plants]. / Khigienna otsenka na toksichnite faktori na rabotnata sreda v osnovni uchast'tsi pri proizvodstovoto na med.

The study embraces the shops: metallurgic, electrolysis, production of sulfuric acid and shop 100. Tests are performed on the environmental pollution by dust, sulfur dioxide, chlorine, aerosols of sulfuric acid, carbon monoxide, nitric oxide and dioxide, hydrogen chloride, arsenic (II) oxide (III), selenium, tellurium and metal aerosols: lead, copper, cadmium and zinc. The total concentrations of chemical noxae, generating multicomponent mixtures with one-way effect on the work place, are reckon, and estimation in the Bulgarian Institute of Hygiene and Occupational Health and the Ministry of public health methods. In the same shop is comprised a representative group of workers with paraclinical tests: GOT and GPT activity, content of copper and zinc in blood. The assessment made on the work conditions and the changes already found in the workers lead to a discussion for optimizing the conditions in the new shops for copper production.

[Electron microscopic methods of studying pollution in the work environment from submicroscopic aerosols]. / Elektronnomikroskopski metodi za izsledvane zamursiavaneto na rabotnata sreda ot submikroskoppichni aerozoli.

The existing method of electron microscope study of working environment pollutions caused by submicroscopic aerosols are summed up and subjected to critical analysis. More particularly, reference is made to the methods of detecting dust particles in the disperse medium for electron microscope study, to determination of the scope of application of these methods, as well as the determination of the effectiveness of detecting filters for submicroscopic aerosols, using electron microscope techniques.