Problemi na khigienata最新文献

At main workplaces in F. "Stomana" (Pernik City) sorting and sheetrolling works, measurements and evaluation of the noise factor were carried out, and hearing sensitivity of workers was investigated in 229 subjects of mean age 36.1 +/- 9.8 years and mean occupational experience 9.7 +/- 7.4 years. Findings at workplaces indicated presence of noise of excessive equivalent levels and pulsing nature varying in degrees. Hearing thresholds for 4 and 6 kHz and average speaking frequency were elevated, and the proportion of subjects with hearing threshold above 30 dB for all frequencies tested was larger among the job groups of roller workers, furnace men, cutters, crane workers, markers, packers, quality control surveyors, and dispatchers as compared to subjects working at lower noise levels or exposed for shorter times to intense noise, notably, operators, fitters, welders, electrotechnicians. Regression analysis revealed the dynamics of change in hearing sensitivity to be more closely related to age than to duration of occupational experience.

Individual exposures were qualitatively and quantitatively characterized for "Xylols" manufacturing workers. To this end, air sampling was performed from the breathing zones of workers occupied at varying jobs, covering a representative group of 29 subjects; for comparison, 17 stationary samples were taken from work-places at the same facility. A gas chromatographic procedure specially developed for the purpose was used for identification and quantitative analysis of the substances recovered. Fatty and aromatic hydrocarbons were found to be the principal pollutants of the occupational atmosphere. The leading pollutant proved to be benzene, by virtue of its high toxicity and relatively high levels (around and above its MAC).

During one year toxicological experiment on white male rats, receiving orally vanadium in doses 0.005 mg/kg, equivalent to the accepted in Bulgaria norm for ist category surface waters and 0.01 mg/kg, equivalent to the actually met in the drinking waters of some regions in this country heightened concentrations, its atherogenic effect is studied by indices: total cholesterol, beta-lipoproteins, phospholipid, lecithin, total lipids, total proteins, and hexoses of glycoprotein in blood serum; hydroxyproline, hexosamines, hexauronic acids and hexoses, connected with the proteins, in the aorta. A methodic approach is used for studying the atherogenic effect of vanadium on the processes of natural aging of the cardiovascular system. It is established that at chronic oral effect of the studied doses of vanadium no changes occur in the biochemical component of the connective tissue of the aorta and there are no infringements of the blood metabolism. In relation to the lipidic-only a decrease in the total cholesterol in the serum is established. The results show, that during the experiment vanadium causes no acceleration in the processes of natural aging of the blood vessels and has no atherogenic effect. Comparing the data for vanadium concentration in the drinking of Bulgaria to our results give grounds to reckon, that its heightened content in drinking waters of some regions presents no risk factor for the development of atherosclerosis.

The study aims at establishing the affective-behavioral orientation in adolescents from the Homes for Children and Adolescents by examining their anxiety and readiness for aggression. In the investigation are included 227 children from 15 to 18 years old. The study is realized by using the questionnaire of Buss Durky for assessing the aggression, questionnaire for anxiety after Ch. Spilburgur and inquiry card for studying the problem of communication, directness of the personality etc. It is presumed that the unequivalant social conditions of life of adolescents from the Homes for Children and Adolescents have negative influence on the affective-behavioral orientation of the latter. We expect the raised aggressiveness to be with dominating hostile affective-cognitive orientation and in compliance with the high levels of uneasyness. The studying of predictors for emotional and behavioral derangements give us a possibility to reveal some subjective and social prerequisites, affecting the behavioral orientation and effective adaptation of juveniles from the Homes for Children and Adolescents.

A polemics on the ecological expedience of the transmitting station "Kaliakra", which is in the process of building, was held. The two opposing sides in the diaput are OOD "Bulgarian Posts and Power-line Communication" and the community of village Balgarevo, district of Varna. The ecological aspect of the project is very well known in the Ministry of the Environment and the Ministry of Public Health, as well as in the National Center of Hygiene, Medical Ecology and Nutrition. The latter has given an expert attitude for the hazardous zones around the site. As a result of this polemics is the delay of the building, i.e. blocking investments and missed opportunities, because of not realized exploitation. Stating the above we would like to expand the competent forum of the engaged in the problem. For this purpose we are ready to discuss with the participants in the Conference the methods and results of the calculations, as well as the normative basis, which were used in determining the hazardous zone. The control calculations point out, that the level of the electromagnetic exposure of the population in the district will be lower than the allowable values, which are given both in the Bulgarian State Standards and the foreign standard documents for hygiene control of nonionizing radiation.

A representative group of 122 workers from shop "Predilen" with 7 to 15 years length of service in specialty is taken. The professional groups are formed on the basis of measured average-shift concentrations of carbon bisulphide in the air of the working place, which vary from 4 to 50 mg.m-3. In order to establish deviations in some of the basic links of the biochemical mechanism of the toxic compounds effect the following indices are traced: copper metabolism [copper concentration and activity of ceruloplasmin in the serum]; lipidic metabolism [content of cholesterol, cholesterol of high and low density, triglycerides, beta-lipoproteins and nonesterified lipidic acids in the serum]; intercellular substance of the connective tissue [glycoproteins, glycosaminoglycans and hexauronic acids in serum and urine]; immune status [immunoglobulins A, G and M in serum]; peripheral blood [leucocytes, DKK, morphology and lipid content in granulocytes]. Decrease of the lipids in granulocytes is registered, as well as reduction of the ceruloplasmin activity, increase of immunoglobulin M and glycosaminoglycans in urine. The already established deviations follow the "dose-effect" and "dose-response" dependence.

When assessing the health risk of benzene and its allowable levels of exposure of special importance is its cancerogenic effect. Bearing in mind, that the cancerogenic substances have no threshold dose, as well as the genetic benzene activity, no safety level of benzene is recommended in the atmospheric air of settlements. The undertakings, in relation to the atmospheric air pollution with benzene, have to be conformed to the admissible risk.

The work considers the problem of ergonomic evaluation on the abilities of the auditory analyzer for speech information processing, depending on the zones of masking effect of noise and the rate of speech communication. Significant increase the loss of speech communication with increase in the intensity of the masking effect of noise (from 21.33% at L eq. 40 dB to 96% at L eq. 90 and above 90 dB/A). The speech communication is determined on scale in 4 zones, depending on the qualitative-quantitative criteria of the speech communication processing [I, II, III and IV zones]. Of point of view of ensuring the necessary conditions for perception of the speech communication is confirmed the correctness of the norm for masking noise L eq. 65 dB/A/, which guarantees a good speech communication. Equivalent levels of the masking noise about or equal to L eq. dB/A/ guarantee a satisfactory speech communication in the command desks. When the intensities of the masking noise are above the norms they are of specific importance, as they fall into the unaccepted (bad) zone, of the auditory perception of speech communication.

The heating-electric plant "Maritsa Iztok" is situated in the area of Stara Zagora, on arable agricultural land, in close vicinity to settlements. It includes three heating plants, working with low caloric coals, of high ashen and sulphuric content and briquet fabric. Two stations for observation and evaluation of the atmospheric air in the district of plant "Maritsa Iztok", the meteorological conditions and geographic situation are chosen according to the Bulgarian State Standards 17, 2, 5, 01-81: station 1-"Gŭlŭbovo" and station 2-"Mednikarovo" for indices--dust, sulphur dioxide, hydrogen sulphide, ammonia, nitrogen peroxide. In order to determine the content of the already mentioned pollutants in the atmospheric air are used Bulgarian State Standards and the results are compared with the corresponding maximum allowable concentrations, according to Regulation No 2 of the Ministry of Health.

The results from gas-mass analysis of the mixture of products from evaporation and volatile products from thermo-oxidizing destruction, eliminated at using lubricating-condensing devices point out, that the evaluation of the toxico-chemical factor concerning only the lubricated aerosol contact is extremely insufficient. The presence of hydrocarbons of different homologs, oxygen and nitrogen derivatives of hydrocarbons has to be taken into consideration. For correct characterization of the conditions of work and risk for the workers of these productions, creating conditions for destructive processes with lubricating oils, is necessary a standardization of the leading components of the vapour-gas phase in the air of the working environment.