coffee grounds and yeast effluent. The inhibitory effect on the germination capacity was alleviated in treatments with biochar. The addition of biochar to compost with sewage sludge decreased the abundance of Escherichia coli and Salmonella ssp. and increased the total number of bacteria and fungi. In the case of composts with coffee grounds, biochar had an opposite effect to that observed for composts with sewage sludge. Conclusions Biochar to sewage sludge and coffee grounds reduced ecotoxicity of composts to test organisms: Vibrio fischeri, Sianpis alba, Triticum L. and Eisenia fetida.

Soil microorganisms play a key role in many biochemical processes essential for the environment and for the ecological and production functions of soils, hence they are very important quality indicators. The study aimed at evaluating the effect of 1 and 2% additions of wheat and miscanthus straw biochars on soil enzymatic activity (dehydrogenases, urease, phosphatases) and the number of microorganisms (bacteria, fungi, actinobacteria). Pot experiments were carried out on soil with a loamy sand texture. The geometric mean of enzyme activities, biological index of fertility, and the integrated total enzyme activity index were used to explore the relationships between soil enzyme activities and the microbiological and chemical properties of soil. The addition of 1% miscanthus straw biochar had the most beneficial effect on the number of bacteria and fungi (increase by 380 and 26%, respectively), and 1% wheat straw biochar on the number of actinomycetes (increase by 273%). The correlation analysis between the number of actinomycetes and the chemical parameters of the soil showed the significant effect of the content of N total (r = 0.76) and C total (r = 0.85). The values of biological index of fertility, total enzyme activity index and geometric mean of enzyme activities indexes showed that the best quality of soil was produced by a 2% addition of wheat straw biochar.

Historical facilities such as churches, crypts, libraries and museums are crucial for preserving cultural heritage but at the same time, they are frequently visited tourist objects and working environment. The aim of this study was to assess whether there are differences in the concentration and size distribution of bacterial and fungal aerosol in the mentioned groups of historical objects in Kraków, as well as to determine if there is tendency for seasonal fluctuations of bioaerosol concentrations, and what environmental parameters affect them most significantly. The concentrations of bacterial and fungal aerosol were measured in ten historical objectschurches, crypts, libraries and museums-using a sixstage Andersen impactor. Microbiological analyses were accompanied by measurements of particulate matter (PM 10 , PM 4 , PM 2.5 and PM 1) and microclimatic parameters. The results showed that the studied objects differ in terms of bioaerosol levels, but the differences were not drastic and in terms of bacterial aerosol concentrations the objects can be arranged as follows: churches [ libraries [ museums [ crypts, while for fungal aerosol the order would be: churches [ museums [ crypts [ libraries. The concentrations of bioaerosol did not exceed the safety levels for human exposure, but the levels suggesting possible threat of biodeterioration and the presence of internal source of contamination were exceeded in nearly all sites. The share of respirable fraction of bioaerosol was high (42.1-90.5% for bacteria and 80.7-94.7% for fungi). Bioaerosol concentration was most significantly associated with indoor temperature, and the impact of particulate matter was only moderate.

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The aim of the investigations was to determine the effect of composting municipal waste with various added substances (starch, edible oil or urea) on the content of selected forms of zinc, cadmium, copper and lead, the quality of organic matter and counts of some groups of physiological microorganisms. The above properties of compost may provide the basis for assessment of the composting process efficiency. The research object was biomass prepared from plant and other biodegradable waste generated in the area of Krakow. The biomass for composting was prepared from the following organic waste: deciduous tree chips, chicory coffee production waste, grass and tobacco waste. There were two stages of the composting process: I-lasting for 14 days, to obtain "heated" compost, and II-lasting for 210 days, when starch, edible oil or urea was added to the composted biomass. The total content of Zn, Cd, Cu and Pb determined in the analyzed composts does not pose a threat to the purity of the soil environment. The content of water-soluble forms of trace elements and forms bound to organic matter was affected by the loss of organic matter, chemical properties of a given element and the addition of supplement, mainly urea, to the composted biomass. Analysis of the fractional composition of humic compounds revealed higher values of the Cha:Cfa ratio in the composts with added edible oil or urea than in the other composts, which may indicate a much more advanced decomposition process of the material subjected to composting. Among the analyzed microorganisms, bacteria were most numerous in the composts. The introduction of urea to the composted biomass reduced microbial activity. Adding starch or oil stimulated microbial development and may have stimulated the composting process.

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Municipal waste plants can be a source of biological contamination of the environment, depending on the method of operation and the type of collected waste. The aim of this study was the quantitative characteristics of airborne microorganisms at the Barycz municipal waste sorting plant in Cracow. Bioaerosol measurements of indoor and outdoor air of the municipal waste sorting plant were performed during the summer season using a six-stage Andersen cascade impactor. The highest concentration of bacterial and fungal aerosol was observed in the medium fraction sorting room (129.02×103 cfu·m-3 and 116.21×103 cfu·m-3, respectively). There were statistically significant differences in the concentrations of bacterial and fungal aerosol between indoor and outdoor air. The calculations showed a significant correlation between the concentration of bioaerosol and particulate matter. Based on the analysis of bioaerosol particle size distribution, it was found that the concentration of bacteria and fungi has a maximum value in the diameter range 3.3-7.0 μm. The study confirmed that the municipal waste sorting plants can be causing exposure to microbiological agents.