[Workers' exposure to selected biological agents in libraries of Upper Silesia]. / Narazenie pracowników na wybrane szkodliwe czynniki biologiczne w bibliotekach województwa slaskiego.

The aim of this study was to assess the exposure of library workers to biological agents based on quantitative and qualitative characteristics of airborne and settled dust microflora supplemented with the analysis of dust mite allergens. The bioaerosol sampling was carried out using a 6-stage Andersen impactor. The settled dust samples were collected from book covers using cotton swabs and vacuum cleaner. Isolated microbial colonies were identified to the genus and/or species level. Moreover, the concentration of guanine as a predictor of dust mite allergen content was determined with the semi-quantitative Acarex test. The bioaerosol concentrations were low and they did not exceed the proposed Polish reference limits. The presence of air-conditioning or ventilating system resulted in the decreased biological contamination in libraries. The identification ofmicroorganisms in bioaerosol and settled dust samples revealed the presence of strains classified into group 2 according to their risk of infection. The level of dust mite allergens was elevated. Inhalation exposure to molds and dust mite allergens may result in the occurrence of allergic reactions and SBS symptoms.

Viability of fungal and actinomycetal spores after microwave radiation of building materials.

The effects of microwave radiation on viability of fungal and actinomycetal spores growing on agar (medium optimal for growth) as well as on wooden panel and drywall (common building construction/finishing materials) were studied. All materials were incubated at high (97-99%) and low (32-33%) relative humidity to mimic "wet" and "dry" environmental conditions. Two microwave power densities (10 and 60 mW/cm2) and three times of exposure (5, 30, and 60 min) were tested to find the most effective parameters of radiation which could be applied to non-invasive reduction or cleaning of building materials from microbial contaminants. Additionally, a control of the surface temperature during the experiments allowed differentiation between thermal and microwave effect of such radiation. The results showed that the viability of studied microorganisms differed depending on their strains, growth conditions, power density of microwave radiation, time of exposure, and varied according to the applied combination of the two latter elements. The effect of radiation resulting in a decrease of spore viability on "wet" wooden panel and drywall was generally observed at 60 min exposure. Shorter exposure times decreased the viability of fungal spores only, while in actinomycetes colonizing the studied building materials, such radiation caused an opposite (supporting growth) effect.

[Assessment of workers' exposure to airborne bacteria at a small wastewater treatment plant]. / Ocena narazenia na aerozol bakteryjny pracowników nieduzej oczyszczalni scieków.

A study of workers' exposure to airborne culturable bacteria was performed at the wastewater treatment plant in Myszków. A six-stage Andersen impactor was used to carry out measurements. The concentrations of total bacterial aerosols ranged from 10(2) to 10(3) CFU/m3 and were lower than the proposed standards. The results of the study show that Gram-negative bacteria contributed to about 35% of the total bacterial aerosol. The largest part of the airborne Gram-negative bacteria constituted Enterobacteriaceae. Pathogenic bacteria found in the air: were as follows: Aeromanas hydrophila, Enterobacter agglomerans, Yersinia enterocolitica, Escherichia coli and Streptococcus faecalis. The microbiological contamination of the air was highest near the aeration basin. Exposure to airborne culturable bacteria may cause respiratory and gastrointestinal symptoms among sewage workers. It is necessary to reduce the exposure to airborne bacteria at this phase of the process of wastewater treatment.