Mercury Vapor Determination in Hospitals

The measurements of metallic mercury vapor were carried out in seven local hospitals, where mercury-containing products are widely used, as well as in one residence to check effectiveness of decontamination after mercury spillage. Hopcalite as a solid sorbent was used in active and passive sampling methods, and mercury was analyzed by CV-AAS technique. Good agreement was found between results of mercury measurements using active samplers (pumped hopcalite adsorption tubes) and passive (diffusion) monitors applied in indoor atmosphere. The results indicated the presence of metallic mercury vaporization sources in the assessed hospital rooms but in the majority of cases mercury levels did not exceed 1 g/m³ i.e. Polish permissible concentration for residence. However, in some of the hospital rooms, elevated concentrations of mercury vapor were found and airborne levels of up to 13.9 g/m³ were recorded. Higher concentrations of mercury vapor were observed in autumn season when compared to summer.     

A Method of Mercury Removal from Topsoil Using Low-Thermal Application

Mercury contamination in the environment is problematic due to the unusual physical properties and well-recognized toxicity of this common metal. The bioavailability of mercury depends strongly on its chemical speciation. Anthropogenic mercury and its compounds appear in soil as hot spots located close to industrial facilities that used or produced mercury. The nature of the chemical production process, transportation and disposal practices often determined the chemical composition and distribution of mercury in the surrounding soils. Current ex situ soil remediation methods are expensive, produce undesirable side effects to the environment and usually involve transportation of contaminated soil.In this project, sponsored by the U.S. Department of Energy, a low-cost, simple approach to removing mercury from soil was evaluated. The process uses low-temperature thermal desorption of volatile metallic mercury and its compounds, and subsequent vapor capture.The project consisted of laboratory and plot-scale experiments. The laboratory efforts evaluated theoretical calculations of mercury removal as a function of time and temperature. The plot-scale experiment was a practical application of the laboratory results. For both experiments, mercury-polluted soil was obtained from a chemical production facility located in southern Poland. In laboratory experiments, at temperature 373 K total mercury concentration decreased in soil by nearly 32%. In plot-scale experiments, at temperature 440 K, about 60–70% of total mercury was removed from the soil.At the end of the experiment, a test of soil biological activity was performed to check if the high temperature applied to the soil did not impair the soil growth properties. There was no negative effect of temperature found.     

The Stream and Its Altered Valley: Integrating Landscape Ecology into Environmental Assessments of Agro-Ecosystems

Little is known about the importance of landscape and land cover to the implementation and performance of agricultural conservation projects designed to improve stream quality. In our study, we addressed the potential importance of landscape and land cover to conservation projects by measuring variation across 191 μ-basins (100–2400 ha) and integrating the observed variation into a study design aimed at determining the effectiveness of conservation projects. Our findings indicate that there are strong gradients across which landscape and land cover attributes vary. Land cover varied along a gradient of agricultural intensity, basin morphometry across gradients of stream closure and basin size, basin substrate was described by variation in drumlin formation, glacial landform type, and soil drainage, while agricultural conservation projects varied according to the level of project implementation. Correlation of these gradients found several associations between landscape and land cover, indicating that agricultural intensity was being constrained predominantly by drumlin formation and glacial landform type. Landscape and land cover did not appear to be determining factors in the implementation of conservation projects by land owners. Based on these findings we chose 32 μ-basins which represented the variability along each of the defined gradients for further study. We conclude that landscape scale variables demonstrate important variation and covariation that can and should be integrated into study designs for the assessment of streams and human activities affecting streams.     

The Effects of Small Dam Removal on the Distribution of Sedimentary Contaminants

With increasing concern over degradation of aquatic resources, issues of liability, and maintenance costs, removal of small dams has become increasing popular. Although the benefits of removal seem to outweigh the drawbacks, there is a relative paucity of studies documenting the extent and magnitude of biological and chemical changes associated with dam removal, especially those evaluating potential changes in contaminant inventories. In August and November of 2000, a run-of-the-river dam on Manatawny Creek (southeast Pennsylvania) was removed in a two-stage process. To assess the effects of dam removal on the contaminant redistribution within the creek, sedimentary concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and trace metals (Cd, Cr, Cu, Ni, Pb, Zn) were evaluated prior to and several months after removal. Pre- and post-removal analyses revealed elevated and spatially variable concentrations of total PAHs (ranging from approximately 200 to 81,000 ng(g dry weight) and low to moderate concentrations of trace metals and PCBs. The concentrations of these sedimentary contaminants pre- versus post-removal were not significantly different. Additionally, though the impoundment received storm water run-off and associated contaminants from the adjacent city of Pottstown, the total inventory of fine-grain sediments in the impoundment prior to removal was very low. The removal of the low-level Manatawny Creek dam did not significantly redistribute contaminants downstream. However, each dam removal should be assessed on a case by case basis where the potential of sedimentary contaminant redistribution upon dam removal exists.     

Energy efficiency and conservation for individual Americans

Americans make up only 4% of the world population, yet currently consume 25% of the world’s fossil fuels. The U.S. imports 63% of its oil and it is predicted that by 2020 the U.S. will be importing 95% of its oil resources. Over the past century, ample and affordable supplies of fossil fuels have powered the growth and prosperity of the economies of the US and other countries. Within this century, world oil supplies will decline while demand is projected to continue to increase, suggesting that we will have to transition to different fuels or become much more energy efficient or both. Looking ahead to the near decades, estimates are that consumers will have to reduce their energy use by at least 50%. This reduction will be necessary in large part due the decline in the availability of conventional oil and gas, but also because the U.S. population will continue to grow in number. Although government action is important, individuals too often discount their ability to make significant contributions to solving such major problems. This investigation identifies how informed and concerned individuals can collectively conserve fossil energy. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. An erratum to this article can be found at     

电子探测系统——边境线安防的重大革命

在这个跨边境恐怖主义活动和非法移民问题多发的年代,世界上的许多国家都在寻找有效保护边境的方法.因此,如何保护被视为"最后一道防线"的周界防护系统国境线成为摆在各国面前的首要问题.     

PCDDs/PCDFs, dl-PCBs and HCB in the flue gas from coal fired CFB boilers

The aim of the project was to measure the actual emissions of polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and hexachlorobenzene (HCB) from four selected power plants in Poland in order to update the national inventory of PCDDs/PCDFs emission. Relatively low PCDDs/PCDFs as well as dl-PCBs concentrations in flue gas obtained in measurements in this study for four different circulated fluidized bed (CFB) boilers indicate practical absence of any hazards caused by PCDDs/PCDFs emission from these units. The results of PCDDs/PCDFs determination obtained in this study indicate that hard coal combustion in large CFB in the four central heating plants (CHP) is not a significant source of PCDDs/PCDFs emission to the environment even if operated by co-firing of waste coal. PCDDs/PCDFs concentration in flue gases as well as emission factors were recorded in the range of 0.012-0.060ngI-TEQ/m(n)(3) and 7.51-46.4mugI-TEQ/TJ, respectively. Dl-PCBs concentration was practically below the LOQ=0.006ng WHO-PCB TEQ/m(n)(3) in all experiments. HCB concentration as well as emission factors were recorded in the range of 11.5-42.0ng/m(n)(3) and 6.19-26.7mg/TJ, respectively, where the highest value was obtained for co-firing of waste coal, however. Obtained in this work emission factors will be used for national emission inventory purposes instead of the factors proposed by Toolkit or taken from previous measurements. However, consideration should be given to the fact that the measurements in most cases are related to single installations. Therefore, the need for further development of national factors for the power generation industry in Poland is desired.     

Why do honey-bee (Apis millifera) foragers transfer nectar to several receivers? Information improvement through multiple sampling in a biological system

The task of nectar foraging in honey-bees is partitioned between foragers and receivers. Foragers typically transfer a nectar load in the nest as sub-loads to several receivers rather than as a single transfer. Foragers experience delays in finding receivers and use these delays to balance the number of foragers and receivers. A short delay results in the forager-recruiting waggle dance whereas a long delay results in the receiver-recruiting tremble dance. Several nectar transfers increase the cost of this system by introducing additional delays in finding extra receivers. We tested four hypotheses to explain the occurrence of multiple transfer. We found no evidence that multiple transfer is due to different crop capacities of foragers and receivers or that it results from extensive trophallactic interactions with nest-mates. Receiver bees frequently evaporate nectar in their mouthparts to hasten the production of honey. The suggestion has been made that multiple transfer is driven by receivers who take partial loads from foragers to enhance nectar evaporation. An alternative suggestion is that foragers drive multiple transfer to gain better information on the balance of foragers and receivers. Multiple sampling of the delay in finding a receiver reduces the standard deviation of the delay mean and so provides foragers with better information than is provided by a single delay. The enhanced-evaporation hypothesis predicts that receivers break foragers' first transfer whereas the information improvement hypothesis predicts foragers break their first transfers. Furthermore, only the information improvement hypothesis predicts a high level of multiple receptions. Data on transfer break-off and receiver behaviour strongly support the information improvement hypothesis and reject the enhanced-evaporation hypothesis. We suggest that multiple transfer is an adaptive sampling mechanism, which improves foragers' information on colony work allocation, and that multiple sampling is a common feature of social insect societies.     

Determination of PCDDs,PCDFs, PCBs and HCB emissions from the metallurgical sector in Poland

Background The aim of the project was to measure the actual emissions of PCDD/F, PCBs and HCB from 20 selected metallurgical installations in Poland, in order to update the national inventory of dioxin emission from metallurgical industry for developing a strategy for dioxins and furans emission abatement from the subject facilities (UNEP 2005). Methods Sampling methodology used in this work was developed at the Cracow University of Technology because of the complexity of simultaneous sampling and determining PCDFs, PCDDs, PCB and HCB. For the determination a GC-MS/MS system was used. Results and Discussion Results from the work indicate that the highest dioxins and PCB concentrations were recorded for iron ore sintering plants at 1.10–1.32 ng total¹ TEQ/Nm³ followed by aluminium scrap melting at 0.03–0.66 ng total TEQ/Nm³. The highest HCB concentrations at 613–1491 ng/Nm³ were also recorded for iron ore sintering plants, whereas at aluminium plants the HCB concentrations were in the range of only 10.1–22.7 ng/Nm³. Conclusions The above investigations indicate that secondary aluminium production is the most significant dioxins source, if calculated as emission factor values. However, iron ore sintering plants are operating at much higher production capacity, causing this process to become the major source of dioxins, PCB and HCB pollution to the atmosphere in Poland. Recommendations and Perspectives Based on the performed tests and the environmental reviews of selected plants several recommendations were formulated for the reduction of generation or of emission of these pollutants from iron ore sintering plants, electric arc furnace steel production processes, hot-blast furnace operations, secondary aluminium smelting and primary zinc production from zinc cathodes.     

Efficiency of ASTM Method D4994-89 for Recovery of Enteric Viruses from Biosolids

The ASTM Method D4994-89 has been used in the United States for almost two decades to assess the virological quality of biosolids. However, the efficiency of this method for recovery of different enteric viruses has never been determined. The method was found to recover several different enteroviruses and adenovirus 2 with an efficiency ranging from 18.1 ± 5.5 to 24.6 ± 7.8%.