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The Environmental Impacts of Fire-Fighting Foams Extinguishing foams are commonly used for extinguishing the fire of flammable liquids, whereby their insulating, choking and quenching effects are exploited. The purpose of the paper is to consider and compare the foams currently used in fire departments, regarding mainly their high extinguishing effect (capability of faster aborted burning on the large surface at low foam consumption), but also their impact on the environment in each stage of their life cycle.

Four polysaccharide samples related to (4-O-methyl-D-glucurono)-D-xylan were analyzed by thermogravimetry (TG) and differential scanning calorimetry (DSC) in nitrogen and oxygen environments. The calculated difference in the measured fG-residues run in different environments and obtained at temperatures close to 300 °C by a dynamic experiment indicate the action of oxygen on the formation of gaseous products. The rats constants and activation energies of the degradation process in both environments indicate the increase in stability due to the protection of hydroxyls by acetylation. In an inert environment xylans have one broad multicomponent exotherm, as determined by dynamic DSC measurement. In an oxygen environment two or three independent exotherms are observed. The pretreatment of xylan with trifluoroacetic acid (solvent used for acetylation) and acetylation lowers the exothermic effect of both the thermolysis and thermooxidation. The recycling of the acetylated xylan to Na + -salt form leads to a greater exothermic effect of the degradation in both environments.

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SUMMARYBackground and Aim: Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion or pyrolysis of various organic materials. Their ubiquity in the environment leads to measurable levels of exposure. However, the exposure varies strongly between different regions in Europe. Some PAHs with four or more rings are suspected to be human carcinogens. Therefore, the occupational and/or environmental exposure to PAHs may cause a significant health risk. The aim of the study was to evaluate current levels of PAH exposure in defined groups of workers.Methods: The industrial sites selected in this survey involved PAHs originating from coal tar pitch, carbon black, bitumen, and rubber fumes. Based on the historical data, the sites were expected to exhibit quantifiable levels of exposure to PAHs. The total study population consisted of 139 persons: 108 workers (85 males and 23 females) occupationally exposed in aluminium production, the production of graphite electrodes, road construction, or the rubber forming industry and 31 control individuals in two groups.Results: The highest concentrations -8-hour time-weighted average (TWA) levels (sum of 16 components according to the EPA list), as expected, were found in the aluminium production plant (55.15 µg.m −3 ) and production of graphite electrodes (54.25 µg.m −3 ). The lowest concentrations were found in personal air samples of road construction workers (1.93 µg.m −3 ). The concentrations of 1-hydroxypyrene as a pyrene metabolite (1-OHP) in the urine of the exposed group of workers were found in levels 0.74 µmol.mol −1 creatinine before the exposure and 2.27 µmol.mol −1 creatinine after the exposure (arithmetic mean values). 1-OHP concentrations in post-shift urine samples were highly correlated with the total airborne PAHs concentrations and pyrene concentrations in air. The correlation coefficients (r S ) between 1-OHP concentration and pyrene or total PAHs in air were 0.710 and 0.752 (p < 0.05). This statistical analysis confirmed the effect of the occupational exposure to PAHs and pyrene on body burden in workers. However, a modifying effect of gender, smoking habits, dietary intake, genetically modified metabolism, and the use of medication on the toxicokinetics of pyrene was not determined as significant.Conclusion: Based on the results a strong correlation between the concentration of 1-OHP in urine as an exposure biomarker and the concentration of pyrene or PAH was affirmed.

This article deals with comparison of the behaviour of spruce wood and polyolefins (polyethylene PE and polypropylene PP) during the test on the cone calorimeter. Samples were tested on the cone calorimeter at heat flux of 20 and 40 kW/m2. An evaluation of the behaviour of examined materials was based on the determination of the maximum and the average heat release rate, yield of carbon monoxide (CO), and relative comparison of tendency to fire propagation in a flashover phase. The tendency of materials to fire propagation in the flashover phase was evaluated based on the Pearson ́s correlation, the Spearman ́s correlation and the Kendall ́s correlation coefficient of HRR-CO and CO2-CO. Spruce wood showed better properties in comparison with PE and PP in all evaluated parameters (the maximum and the average heat release rate, the yield of CO, and also the resistance to fire propagation in the flashover phase. Additionally, spruce wood showed significantly lower sensitivity of dependence of the maximum and also the average heat release rate on external heat flux.

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