The Cytotoxicity of Some Organic Solvents on Isolated Hepatocytes in Monolayer Culture

The cytotoxic effects of volatile and water-insoluble organic solvents (ethylbenzene, tetrachloroethylene, n-hexane) were tested on isolated hepatocytes in monolayer culture by using the 3-(4,5 dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) reduction assay. All of the tested compounds inhibited metabolic activity of hepatocytes and this effect depended on the concentration of solvents in the incubatory medium. The presence of fetal calf serum in the medium did not change the cytotoxicity of xenobiotics. IC₅₀ values calculated on the basis of the MTT assay indicated that ethylbenzene was more cytotoxic than tetrachloroethylene and n-hexane. Using hepatocyte monolayer culture and the MTT assay to assess cytotoxicity of organic solvents causes many technical problems. It seems that it cannot be used as a rapid, cheap, and credible method.     

Body Heat Balance of a Man with Deficient Sweat Rate Subjected to Physical Work in a Hot Environment

The dynamics of physiological stress and thermal balance were investigated in men subjected to endogenous and exogenous heat loads. The study was conducted using the thermometric method. Substantial differences in the dynamics of the tested parameters and their quantitative characteristics were observed in 1 out of 8 participants. In this article, the observed differences are rationalized in terms of the deficient sweat rate mechanism. It is pointed out that it is indispensable to address these cases in work safety regulations.     

Work ability in ageing workers suffering from chronic diseases.

The aim of this study was to investigate the work ability in ageing workers suffering from osteoarthritis (OA), coronary heart disease (CHD) or hypertension (H). One hundred and sixty-six OA and 355 CHD/H outpatients were evaluated. The Work Ability Index (WAI) served for work ability assessment. Patients' results were compared with the results of a control group of 225 healthy young workers. Statistical analysis was performed with ANOVA tests. WAI in female and male CHD/H patients was higher than in OA patients (p < .01), better work ability was related to better education (p < .01), white-collar work (p < .01) and better recreation (p < .01); subjective work ability was determined mostly by the objective health status. The promotion of work ability among workers suffering from advanced age-related diseases should be closely related to the promotion of health. It is indicative to improve occupational education and skills, already at an early stage of a disease.     

Plutonium bioaccumulation in seabirds

The aim of the paper was plutonium (²³⁸Pu and ^239+240Pu) determination in seabirds, permanently or temporarily living in northern Poland at the Baltic Sea coast. Together 11 marine birds species were examined: 3 species permanently residing in the southern Baltic, 4 species of wintering birds and 3 species of migrating birds. The obtained results indicated plutonium is non-uniformly distributed in organs and tissues of analyzed seabirds. The highest plutonium content was found in the digestion organs and feathers, the smallest in skin and muscles. The plutonium concentration was lower in analyzed species which feed on fish and much higher in herbivorous species. The main source of plutonium in analyzed marine birds was global atmospheric fallout.     

Monitoring the multi-year carbon balance of a subarctic palsa mire with micrometeorological techniques

This article reports a dataset on 8 years of monitoring carbon fluxes in a subarctic palsa mire based on micrometeorological eddy covariance measurements. The mire is a complex with wet minerotrophic areas and elevated dry palsa as well as intermediate sub-ecosystems. The measurements document primarily the emission originating from the wet parts of the mire dominated by a rather homogenous cover of Eriophorum angustifolium. The CO(2)/CH(4) flux measurements performed during the years 2001-2008 showed that the areas represented in the measurements were a relatively stable sink of carbon with an average annual rate of uptake amounting to on average -46 g C m(-2) y(-1) including an equally stable loss through CH(4) emissions (18-22 g CH(4)-C m(-2) y(-1)). This consistent carbon sink combined with substantial CH(4) emissions is most likely what is to be expected as the permafrost under palsa mires degrades in response to climate warming.     

Selenium and 17 other largely essential and toxic metals in muscle and organ meats of Red Deer (Cervus elaphus)--consequences to human health

Concentrations, composition and interrelationships of selenium and metallic elements (Ag, Ba, Cd, Co, Cr, Cs, Cu, Ga, Mn, Mo, Pb, Rb, Sb, Sr, Tl, V and Zn) have been examined in muscle and organ meats of Red Deer hunted in Poland. The analytical data obtained were also discussed in terms of Se supplementation and deficit to Deer as well as the benefits and risk to humans associated with the essential and toxic metals intake resulting from consumption of Deer meat and products. These elements were determined in 20 adult animals of both sexes that were obtained in the 2000/2001 hunting season from Warmia and Mazury in the north-eastern part of Poland. The whole kidneys contained Ba, Cd, Cr, Ga, Pb, Se, Sr and Tl at statistically greater concentrations than liver or muscle tissue from the same animal. Liver showed statistically greater concentrations of Ag, Co, Cu, Mn and Mo than kidneys or muscle tissue, and muscle tissue was richer in Zn, when compared to the kidneys or liver. Cs and Rb were similarly distributed between all three tissue types, while V was less abundant in liver than kidneys or muscle tissue. There were significant associations between some metallic elements retained in Red Deer demonstrated by Principal Component Analysis (PCA) of the data set. In organ and muscle meats (kidneys, liver and muscle tissue considered together) the first principal component (PC1) was strongly influenced by positively correlated variables describing Se, Ba and Cd and negatively correlated variables describing Ag, Co, Cs, Mn, Pb, Tl and V; PC2, respectively, by Cu, Mn and Mo (+) and Zn (-); PC3 by Ga (+) and PC4 by Sb (+). Selenium occurred in muscle tissue, liver and kidneys at median concentrations of 0.13, 0.19 and 4.0mg/g dry weight, respectively. These values can be defined as marginally deficient (< 0.6mg Se/kg liver dw) or satisfactory (≤ 3.0mg Se/kg kidneys dw) for the amount required to maintain the Deer's body condition and health, depending on the criterion for supplementation used. In terms of human nutritional needs, a relatively high selenium content of kidneys can be beneficial. The muscle meat, liver and kidneys of Red Deer can be considered as a very good source of essential Co, Cr, Cu, Mo, Mn, Se and Zn in the human diet. Lead is generally considered as toxic, and the concentrations found in Red Deer (via the food chain intake) were well below the European Union tolerance limit. Pb from the lead bullets can always create food hygienic problem, if not well recognized during sanitary inspection, and this was noted for one muscle meat sample in this study (5% surveyed). There is no tolerance limit of Cd in game animal meats. The median values of Cd noted in fresh muscle tissue, liver and whole kidneys were 0.07, 0.18, and 3.3mg/kg wet weight, respectively. Cd exists as a chemical element present at trace levels in plants and mushrooms in Deer's food chain in background (uncontaminated) areas. When these are consumed by the Deer, the amount of Cd sequestered with metallothioneins and retained in the organ and muscle meat in this study is low enough to be considered safe for human consumption.     

The reduction of dioxin emissions from the processes of heat and power generation

The first reports that it is possible to emit dioxins from the heat and power generation sector are from the beginning of the 1980s. Detailed research proved that the emission of dioxins might occur during combustion of hard coal, brown coal, and furnace oil as well as coke-oven gas. The emission of dioxins occurs in wood incineration; wood that is clean and understood as biomass; or, in particular, wood waste (polluted). This paper thoroughly discusses the mechanism of dioxin formation in thermal processes, first and foremost in combustion processes. The parameters influencing the quantity of dioxins formed and the dependence of their quantity on the conditions of combustion are highlighted. Furthermore, the methods of reducing dioxin emissions from combustion processes (primary and secondary) are discussed. The most efficacious methods that may find application in the heat and power generation sector are proposed; this is relevant from the point of view of the implementation of the Stockholm Convention resolutions in Poland with regard to persistent organic pollutants.     

Territory choice during the breeding tenure of male sedge warblers

A territorial male can shift the location of its territory from year to year in order to increase its quality. The male can base its decision on environmental cues or else on its breeding experiences (when territory shift is caused by breeding failure in previous seasons). We tested these possible mechanisms of territory choice in the sedge warbler (Acrocephalus schoenobaenus), a territorial migrating passerine that occupies wetlands. This species bases its territory choices on an environmental cue: tall wetland vegetation cover. We found that the magnitude of territory quality improvement between seasons (measured as the area of tall wetland vegetation) increased throughout the early stages of a male's breeding career as a result of territory shifts dependent on the earliness of arrival. The distance the territory was shifted between seasons depended negatively on the previous year's territory quality and, less clearly, on the previous year's mating success. On the other hand, previous mating or nesting success had no influence on territory quality improvement between seasons as measured in terms of vegetation. The results imply that tall wetland vegetation is a long-term, effective environmental cue and that a preference for territories in which this type of landcover prevails has evolved into a rigid behavioral mechanism, supplemented by short-term individual experiences of breeding failure.     

Estimation of Polish cigarettes contamination with cadmium and lead, and exposure to these metals via smoking

To estimate exposure to cadmium (Cd) and lead (Pb) through cigarette smoking, the concentrations of both metals in the blood or/and urine of smokers (20 cigarettes or more per day for 10 years or longer) and their non-smoking counterparts inhabiting an environmentally unpolluted area (Bialystok, Poland) were evaluated, as well as Cd and Pb contents in the cigarette brands (produced in Poland) smoked by the participants, including intact cigarettes, pre-smoking (tobacco, paper and filter) and post-smoking (butt, ash and smoke) cigarette components. Blood and urinary Cd concentrations in the smokers have been already reported by us to be 2–4 times higher than in the non-smokers (Galażyn-Sidorczuk et al. Polish Journal of Environmental Studies, 13 (Suppl.1):91–95, 2004). All the other measurements are the subject of the present paper. Pb concentration in the blood of the cigarette smokers (52.12 ± 15.51 μg l⁻¹) was higher by 29% than in the non-smokers (40.42 ± 11.19 μg l⁻¹). The mean Cd and Pb contents in the cigarettes were 0.6801 ± 0.1765 and 0.6853 ± 0.0746 μg per cigarette, respectively. Under cigarette burning, performed using a machine for self-acting burning, on average 33% of Cd and 11% of Pb present in the whole cigarette was released into the smoke. For Cd, unlike Pb, there was a high positive correlation between the metal content in cigarettes and tobacco and its release into the smoke. Moreover, the subjects smoking cigarettes containing the highest Cd amount had higher blood Cd concentration than smokers of other cigarette brands. The results give clear evidence that in the case of inhabitants of areas unpolluted with Cd and Pb habitual cigarette smoking, due to tobacco contamination, creates a serious source of chronic exposure to these metals, especially to Cd.     

Estimation of energy demand of fermentation-based hydrogen production

The paper is concerned with estimation of heat and power consumption in a conceptual plant to produce hydrogen from sucrose-containing or starchy biomass by fermentation. A hydrogen plant connected with a sugar factory is regarded as the basic option; the sugar factory serves as a source of sucrose-containing thick juice for the hydrogen plant, where this feedstock is processed to hydrogen. As another option, a stand-alone hydrogen plant in which starch must initially be converted to fermentable glucose solution is considered. The values of key process parameters are assumed on the basis of preliminary experimental data. For both options of the hydrogen plant, heat consumption is estimated taking heat recovery in a heat exchanger network into account. Power consumption is estimated by calculating power needed for pumping of liquid and gaseous process media.