[Silicon carbide, occupational exposure, proposed MAC values].

Occupational exposure to dust silicon carbide production and exploitation of its products was evaluated. Individual dosimetry was used to measure concentrations of total and respirable dusts; concentration of respirable mineral fibres was measured by means of light microscopy; the distribution of fiber length was analysed by employing a laser FM-7400; morphology of dust molecules was analysed in light and electron microscopes; x-ray diffraction and infrared spectrometry was used to identify dust mineral composition. Concentrations of total dust at workposts involved in silicon carbide production ranged between 5.

[Evaluation of occupational exposure of workers engaged in mining of rock raw materials in the Sleza massif].

In two serpentinite mines and in a factory producing asphalt pavements using serpentinite, exposure to dusts and polycyclic aromatic hydrocarbons (WWA-fraction soluble in benzene) was assessed. In rock samples taken in the serpentinite mine and in dust samples from work posts crystalline phases were determined (using X-ray radiography and spectrometry in infrared). Also, morphology of dust particles was performed using electron microscopy.

[Fly ash and its biological effects. 3. Exposure to dust of workers in the energy-generating industry (power plants and thermoelectric power stations)].

An evaluation of exposure to dust of workers employed at typical work-stands in power industry plants was made. Mean concentrations of respirable dust determined at 14 different work-posts range from 0.45 to 8.

[Biological and histological changes induced by cement dust].

In animal experiments pneumoconiogenic properties of metallurgic and Portland cement dust, produced in Poland, were investigated. Experimental pneumoconiosis was developed by intratracheal single administration, to white rats, of 50 mg of dust suspended in 0.6 ml of NaCl physiological solution.

[Evaluation of work environment in the flax textile industry. V. Air microflora in the flax spinning and flax weaving rooms].

Microbiological air pollution in spinning and weaving rooms was determined by aspiration impinger using an aeroscop (Chirana, Czechoslovakia). The air samples were taken on Petri dishes with Bacto-broth-agar (Difco) or Bacto-blood-agar (Difco). After incubation at 37 degrees C for 24 h the number of bacterial or mould colonies and bacterial cells per 1 m3 of the air was calculated.