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261.
A laboratory bench-scale column study was conducted to evaluate permeable reactive filter materials as a new method for removal of heavy metals and inorganic nitrogen from landfill leachate. Mixtures of sand and peat, blast-furnace slag (BFS) and peat, and Polonite and peat were tested by loading columns with leachate collected from a pond at Tvetaverket Landfill, Sweden. Sand, peat and Polonite represent natural materials. BFS is a by-product from steel-works. The metal treatment efficiencies of the media were assessed and Polonite was found to perform best, where Mn, Fe, Zn and Cu concentrations were removed by 99%, 93%, 86% and 67%, respectively. This material was also able to reduce inorganic N by 18%. The BFS showed good removal efficiency for Cu (66%), Zn (62%), Ni (19%) and Mo (16%). The sand-peat mixture did not demonstrate a promising removal capacity for any of the elements studied with the exception of Cu (25%). The removal of different elements was suggested to be a combination of several factors, i.e. precipitation, ion exchange and adsorption. Prior to full-scale application of reactive filters at a landfill site, matrix selection, filter design and operational procedures must be developed.  相似文献   
262.
We analyzed occupational exposure to potentially infectious body fluids among health care workers (HCWs). Nurses were the most common exposed category of HCWs. In 73.6% cases needle sticks had been the reason of exposure. Recapping a needle was the cause of exposure in 6.9% accidents. Among 189 registered HCWs, 66 (34.9%) performed invasive procedures without any personal protective equipment. Prophylaxis with antiretroviral drugs was necessary in 43 (22.8%) cases. As many as 60.3% of exposure incidents to potentially infectious material result from non-compliance with the relevant recommendations. Continuous education and training is critically needed to prevent occupational exposure to blood-borne infections among health care workers.  相似文献   
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The general properties of piezoelectric sorption detectors utilised in the detection of air pollution have been characterised. Examples of detection, with the aid of these detectors, of the organophosphorus compounds, sulphur dioxide, ammonia, hydrocarbons and their derivatives and other air pollutants have been given. Based on information given in this paper, general conclusions including advantages, and difficulties of using piezoelectric detectors in practice have been described.  相似文献   
267.
Cadmium effects on the ovary structure and oocytes were tested in earthworms Dendrobaena veneta exposed to 10 and 50 mg Cd kg(-1) in soil after 10 and 20 days of the experiment. In both experimental doses cadmium caused damage to the structure of the ovary but the effects were different in each group. At 10 mg Cd kg(-1) concentration in soil, young stages of oocytes and trophocytes were most sensitive to cadmium deleterious effects whereas somatic cells in the ovarian stroma were only slightly affected. Cadmium. at a concentration of 50 mg Cd kg(-1) in soil caused most damage in the somatic cells leading to the occurrence of unnaturally swollen elements and desmosomes destruction. At both experimental concentrations cadmium induced degenerative changes in cell nuclei and an increase in number of cell organelles (RER and Golgi complex elements) in the cytoplasm of oocytes and trophocytes. These also proved to be more active. No ultrastructural changes were manifested in oogonia. In both experimental groups degenerative changes occurred as early as after 10 days of Cd exposure.  相似文献   
268.
The aim of this study was to evaluate the potential role of office fomites in respiratory (human parainfluenza virus 1—HPIV1, human parainfluenza virus 3—HPIV3) and enteric (norovirus GI—NoV GI, norovirus GII—NoV GII) viruses transmission by assessing the occurrence of these viruses on surfaces in office buildings. Between 2016 and 2017, a total of 130 surfaces from open-space and non-open-space rooms in office buildings located in one city were evaluated for HPIV1, HPIV3, NoV GI, and NoV GII viral RNA presence. Detection of viruses was performed by RT-qPCR method. Study revealed 27 positive samples, among them 59.3% were HPIV3-positive, 25.9% HPIV1-positive, and 14.8% NoV GII-positive. All tested surfaces were NoV GI-negative. Statistical analysis of obtained data showed that the surfaces of office equipment including computer keyboards and mice, telephones, and desktops were significantly more contaminated with respiratory viruses than the surfaces of building equipment elements such as door handles, light switches, or ventilation tracts (χ 2 p = 0.006; Fisher’s Exact p = 0.004). All examined surfaces were significantly more contaminated with HPIVs than NoVs (χ 2 p = 0.002; Fisher’s Exact p = 0.003). Office fomites in open-space rooms were more often contaminated with HPIVs than with NoVs (χ 2 p = 0.016; Fisher’s Exact p = 0.013). The highest average concentration of HPIVs RNA copies was observed on telephones (1.66 × 102 copies/100 cm2), while NoVs on the light switches (1.40 × 102 copies/100 cm2). However, the Kruskal–Wallis test did not show statistically significant differences in concentration levels of viral RNA copies on surfaces between the all tested samples. This study unequivocally showed that individuals in office environment may have contact with both respiratory and enteric viral particles present on frequently touched surfaces.  相似文献   
269.
The Niepo?omice Forest, a large forest complex (11,000 ha), situated about 20 km from a large steel mill and about 40 km from the city of Cracow was the object of study. Sulphur dioxide emitted by the steel mill and the city has already caused acidification of the environment of the Niepo?omice Forest. The degree of such acidification was estimated using tree bark as a bioindicator. The pH value and buffer capacity were determined for three tree species — Quercus robur, Tilia cordata and Pinus sylvestris. The bark of all trees showed acidic reaction ranging from pH 2.2 to 4.7. Difference in pH of bark were found between various localities. The bark of examined species was much more acidic in the western part in the Niepoo?mice Forest than in the eastern part of the forest complex. The buffer capacity of bark also differs in various localities increasing with SO2 concentration in the air. A good correlation between acidification of tree bark and the concentration of SO2 in the air of Niepo?omice Forest was found; therefore tree bark may be regarded as a good bioindicator and recommended for practical use to estimate the degree of air pollution. The procedure of sampling and analysis of tree bark is described in detail.  相似文献   
270.
Although shell colour polymorphism of the land snail Cepaea nemoralis is a well-known phenomenon, proximate and ultimate factors driving its evolution remain uncertain. Polymorphic species show variation in behavioural responses to selective forces. Therefore, we estimated effects of various environmental factors (temperature, humidity, food availability, (micro)habitat structure and predatory pressure) on behavioural response (frequency of locomotion, climbing and hiding) of C. nemoralis morphs, in experimental and natural conditions. In the experimental part of study, the frequency of locomotion was negatively affected by temperature and the presence of food and positively influenced by the presence of light. Morphs significantly differed in behavioural responses to environmental variability. Pink mid-banded and yellow five-banded morphs climbed less often and hide in shelter more often than yellow and pink unbanded individuals when temperature was low and food was absent. Snails fed most often at moderate temperature compared to low and high temperatures. Field investigations partially confirmed differences among morphs in frequency of climbing, but not in terms of probability of hiding in sheltered sites. In natural colonies, temperature and (micro)habitat structure significantly affected frequency of climbing as well as hiding in shelter. Snails more often hid in sheltered sites where thrushes preyed on Cepaea. Tendency of unbanded morphs to climb trees may have evolved under avian predatory pressure as thrushes forage on a ground. Tendency of banded morphs to hide in sheltered sites may reflect prey preferences for cryptic background. The results implicate that differential behaviour of C. nemoralis morphs compensate for their morphological and physiological limitations of adaptation to habitat.  相似文献   
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