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1.
With the number of electromagnetic field sources in human environments increasing, it appears appropriate to discuss the future levels of radio frequency (RF) exposure. However, general quantitative assessment is impeded by a fundamental lack of current data. Nevertheless, major technological trends and innovation paths are presented and evaluated with respect to their effect on exposure levels. The most relevant wireless standards and their RF characteristics are briefly introduced. The factors influencing RF exposure are treated in a systematic fashion. A simple exposure-oriented classification of present and future RF sources is introduced to facilitate a structured discussion. The most relevant levers for limiting future exposure levels are presented and some general conclusions are drawn.  相似文献   

2.
Pervasive Computing will bring about both additional loads on and benefits to the environment. The prevailing assessment of positive and negative effects will depend on how effectively energy and waste policy governs the development of ICT infrastructures and applications in the coming years. Although Pervasive Computing is not expected to change the impact of the technosphere on the environment radically, it may cause additional material and energy consumption due to the production and use of ICT as well as severe pollution risks that may come about as a result of the disposal of electronic waste. These first-order environmental impacts are to be set off against the second-order effects, such as higher eco-efficiency due to the possibility to optimize material and energy intensive processes or to replace them by pure signal processing (dematerialization). The potential environmental benefits from such second-order effects are considerable and can outweigh the first-order effects. But changes in demand for more efficient services (third-order effects) can counterbalance these savings. The experience gained thus far with ICT impacts has shown that such a rebound effect occurs in most cases of technological innovations.  相似文献   

3.
Despite heavy investment in integrated information systems, many business problems still prevail due to a lack of integration between the real and virtual world. Low data granularity presently limits enterprise computing. In order to solve these problems, data granularity needs to be increased and the digital management control loop must to be closed. Pervasive Computing, including automatic identification, is the technological enabler. Once closed digital management control loops are in place and generating high data granularity, incremental process changes such as an automatic quality check, enhance the overall efficiency of controlling intensive processes. Object value logging and embedded services are examples of more radical changes, which not only affect processes, but also business models. However, although the pervasive technology-based development road map of future enterprise computing systems seems to be straightforward, various risks and challenges have the potential to strongly influence the technology adoption path.  相似文献   

4.
Visions of Pervasive Computing and ambient intelligence involve integrating tiny microelectronic processors and sensors into everyday objects in order to make them “smart.” Smart things can explore their environment, communicate with other smart things, and interact with humans, therefore helping users to cope with their tasks in new, intuitive ways. Although many concepts have already been tested out as prototypes in field trials, the repercussions of such extensive integration of computer technology into our everyday lives are difficult to predict. This article is a first attempt to classify the social, economic, and ethical implications of this development.  相似文献   

5.
The environmental risks from the use of silver-containing clothes (“silver clothes”) were assessed for an urban area. First, we evaluated whether the use of silver clothes may cause contamination of wastewater treatment sludge that exceeds certain risk thresholds. Second, we assessed the risk of silver exposure to earthworms from applying the sludge as fertilizer to agricultural land. The most critical parameter was the concentration of silver in silver clothes, for which estimates in the literature vary by more than five orders of magnitude. For concentrations at the high end of that parameter range, there is considerably increased concentration of silver in the sludge, and toxic effects on earthworms even at modest use rates of silver clothes suggest high risk. At the low end, no risks can be expected. The main recommendation from this study is that if silver is used in clothes, the silver concentration must be kept at the lower end of the range applied in this study if risks are to be avoided. This can be done either by design choices of companies, or by regulation. If the function of the applied silver is not maintained at these lower levels, the use of silver clothes should be minimized.  相似文献   

6.
Assessing and managing the ecological risks from multiple stressors is becoming increasingly important as our environmental and regulatory focus moves from managing point sources to one of managing and trading risks from multiples sources over large geographic areas. There are important corollaries to this shift in focus and scale, one is the increased role and importance of non-chemical stressors in shaping and controlling ecological systems, the fact that these categories of stress are, for the most part, not regulated under the traditional legislative mandates, that we have limited knowledge regarding the interaction of chemical and non-chemical stressors, that at large scales we are faced with the integration of and trading of risks to multiple resource categories. This trend of increased attention to regional-scale environmental issues requires the development of new analysis and interpretive strategies and highlight the need for a systematic framework for addressing the ecological effects of multiple stressors at regional ecological scales. We propose that such a framework have three essential properties: it be risk-based; it be effects driven; and it have the flexibility to be used in both a retrospective and prospective manner. While several approaches have been proposed we believe that an ecological risk assessment framework satisfies these criteria, has been used successfully in regional assessments, and can readily be modified and adapted to serve a wide variety of problem settings.  相似文献   

7.
Previous studies have shown that Oil-Mineral-Aggregate (OMA) formation enhances the dispersion of marine oil spills, but the potential impacts of settled OMAs on benthic organisms are not well known. A comprehensive numerical approach is proposed here to model the transport of OMAs and assesses their potential risks. The predicted environmental concentrations (PEC) of settled oil in OMAs was calculated using a random walk particle tracking model and the benchmark concentrations (BCs) of individual hydrocarbon groups were computed based on a equilibrium partitioning (EqP) approach. The likely of risks in terms of Hazard Quotient (HQ) were then determined using a Monte Carlo simulation method. HQ for both aliphatic and aromatic hydrocarbon groups were calculated for OMAs formed with two sediments, Mississippi River Delta (MRD) and Standard Reference Material (SRM). Mean total HQs were also determined by a simple sum of individual HQ. The predicted results from a case study based on a spill of 1000 tons of South Louisiana crude oil in the Gulf of St. Lawrence with a water depth of 80 m show that the SRM is unlikely to cause adverse impacts but this may not be the case for MRD. Furthermore, it has been found that the application of chemical dispersant (CD) increased the risks of MRD but it had little effects on SRM.  相似文献   

8.
Protein-based drugs are the fastest growing class of drugs for the treatment of disease in humans and other animals. However, the current method of producing proteins for pharmaceutical application is predicted to fall short because of population growth and demographic trends. This study characterized human dietary risks using quantitative risk assessment techniques for three pharmaceutical proteins produced in field-grown maize. The three proteins were aprotinin, gastric lipase, and Escherichia coli heat-labile enterotoxin B subunit (LT-B). The human dietary risks from the three proteins inadvertently occurring in food were evaluated using three different exposure scenarios so that potential risks could be compared. The three exposure scenarios ranged in conservatism to evaluate the range of risk between the proteins and scenarios. Risk quotients (RQs) were calculated for all three scenarios to integrate exposure and effect (toxicity). The risk assessments revealed that the most conservative scenario produced higher RQs than the other two scenarios. The dietary risks from scenario 1 for aprotinin were three orders of magnitude greater than for scenario 2, and four orders of magnitude greater than for scenario 3. This risk assessment revealed that dietary risks will vary dramatically and depend on factors such as the specific pharmaceutical protein, protein expression, and exposure scenarios. The assessment also reinforced the need for case-by-case assessments.  相似文献   

9.
计算生态学的形成与发展   总被引:4,自引:0,他引:4  
1 计算生态学产生的背景1998年在意大利召开的统计生态学国际大会上 ,与会者普遍认为 ,随着计算机技术的普及和计算方法的推广 ,数字化、模型化、智能化、可视化技术已经被广泛地应用到生态学计算领域中 ,依托计算机技术而进行的生态学计算正蓬勃兴起并迅速发展 ,在生态学中起着越来越重要的作用 ,已经形成了一个新的生态学分支计算生态学 (computingecol ogy)。计算生态学的概念一经提出就倍受重视 ,各国的生态学家 ,目前正在努力发展和完善这一新兴学科领域。与其它科学相比 ,计算生态学的产生具有特殊的历史背景。一方…  相似文献   

10.
In 1996, the U.S. Environmental Protection Agency (USEPA) developed the Adult Lead Methodology (ALM) to provide an interim approach to assessing risks from non-residential exposures to lead. Because such exposures often involve occupational activities of adults, the ALM was directed at assessing soil-related lead risks to adults. Consistent with other approaches used in Superfund risk assessment, the ALM was designed to predict quasi-steady state blood lead concentrations (PbB) that might result from soil exposure. These predictions are converted to a risk estimate, expressed as the probability of exceeding a PbB level of concern. To examine the assumptions and variables in the ALM that have become available since 1996, a comparison was made of the attributes of seven alternative research models for which adequate documentation is available to understand and implement each approach. Several of these models have been used in regulatory decision-making; however, the USEPA has officially embraced none for general use. This analysis suggests that the ALM can continue to serve as a reasonable tool for assessing risks associated with non-residential exposures to soil. Under certain circumstances other models may be more applicable (i.e., for assessing acute or intensive exposures); however, the ALM is recommended for the majority of risk assessment applications.  相似文献   

11.
Several future applications have been suggested for the nanomaterial graphene, and its production is increasing dramatically. This study is a review of risk-related information on graphene with the purpose of outlining potential environmental and health risks and guide future risk-related research. Available information is presented regarding emissions, environmental fate, and toxicity of graphene. The results from this study indicate that graphene could exert a considerable toxicity and that considerable emission of graphene from electronic devices and composites are possible in the future. It is also suggested that graphene is both persistent and hydrophobic. Although these results indicate that graphene may cause adverse environmental and health effects, the results foremost show that there are many risk-related knowledge gaps to be filled and that the emissions of graphene, the fate of graphene in the environment, and the toxicity of graphene should be further studied.  相似文献   

12.
Ecological risk assessment (ERA) of metals, metalloids, and inorganic metal substances (collectively referred to as metals) no longer focuses solely on persistence and bioaccumulation, but rather on solubility, toxicity, natural occurrence (concentrations above/added to background), essentiality (deficiency as well as excess), speciation, and bioavailability. Tolerance (both acclimation and adaptation) and possible resultant energetic costs are being considered, and realism is being increased in laboratory toxicity tests by the use of organisms pre-acclimated to natural levels of metals. The present status of ERAs for inorganic metals is summarized in terms of four key questions: (1) Do metals accumulate in biota above background levels? (2) Are these metals metabolically active? (3) If so, are they likely to result in adverse effects to individuals either alone or in combination with other stressors? (4) If so, are they likely to result in adverse impacts to populations? The most pragmatically useful future research will be that focused on the interactive risks of both complex chemical mixtures (metals and non-metals) and non-chemical stressors (both biotic and abiotic). Ideally this should occur in the context of continued metal loadings to terrestrial and aquatic ecosystems assessed holistically, including trophic food web relationships, metal transfer, and genetic diversity. Relationships between environmental concentrations and internal, metabolically active doses are the key to understanding and predicting environmental risks without excessive reliance on safety factors.  相似文献   

13.
Botanical dietary supplements have a long history of use in Europe and Asia, but the use of these products is becoming increasing popular in the United States. Because these products are classified as dietary supplements, the U.S. Food and Drug Administration does not routinely monitor them for environmental contaminants. Ginseng served as a model botanical dietary supplement and was purchased from suppliers in the United States, Europe, and Asia. Samples were analyzed for metals (e.g., cadmium, nickel) and chlorinated pesticides (e.g., PCNB, DDT, and metabolites). Flame and furnace atomic absorption spectrophotometry were utilized for analysis of metals, while gas chromatography (GC) and GC-mass spectrophotometry were utilized for analysis of chlorinated pesticides. Because no formalized guidelines exist to determine risk of botanical dietary supplements, U.S. Environmental Protection Agency guidelines for protection of human health were used. Metals and chlorinated organics were found in Ginseng samples, but the concentrations posed no noncarcinogenic hazard; however, a 1000?mg/d dose for 350?d/yr resulted in 1 × 10?6 carcinogenic risk in 19% of the Ginseng samples analyzed. At a lower usage rate (42?d/yr), no samples exceeded 1 × 10?6 risk. Chlorinated organics, such as aldrin and heptachlor epoxide, accounted for the carcinogenic risk (1 X 10-6) in the Ginseng samples.  相似文献   

14.
The Exxon Valdez oil spill occurred more than two decades ago, and the Prince William Sound ecosystem has essentially recovered. Nevertheless, discussion continues on whether or not localized effects persist on sea otters (Enhydra lutris) at northern Knight Island (NKI) and, if so, what are the associated attributable risks. A recent study estimated new rates of sea otter encounters with subsurface oil residues (SSOR) from the oil spill. We previously demonstrated that a potential pathway existed for exposures to polycyclic aromatic hydrocarbons (PAHs) and conducted a quantitative ecological risk assessment using an individual-based model that simulated this and other plausible exposure pathways. Here we quantitatively update the potential for this exposure pathway to constitute an ongoing risk to sea otters using the new estimates of SSOR encounters. Our conservative model predicted that the assimilated doses of PAHs to the 1-in-1000th most-exposed sea otters would remain 1–2 orders of magnitude below the chronic effects thresholds. We re-examine the baseline estimates, post-spill surveys, recovery status, and attributable risks for this subpopulation. We conclude that the new estimated frequencies of encountering SSOR do not constitute a plausible risk for sea otters at NKI and these sea otters have fully recovered from the oil spill.  相似文献   

15.
Food, drinking water, soil, and air are the main routes of exposure to trace metals, thus the assessment of the risks posed to humans by these elements is important. Wheat, potatoes, and maize are very important parts of the Iranian diet. The objectives of this study were to estimate the non-carcinogenic and carcinogenic health risks of Hg, Pb, Cd, Cr, Se, As, and Ni to adults and children via soil, water, and major food crops consumed in Hamedan Province, northwest Iran, using the total non-cancer hazard quotient (THQ) and cancer risk assessment estimates. Total non-cancer hazard of Ni and Hg, were greater than 1, and total cancer risk of As and Pb was greater than 1 × 10?6. Food consumption was identified as the major route of human exposure to metals, and consuming foodstuff threatens the health of the studied population. In Hamedan Province, consumption of wheat is the main source of intake of metals from foodstuff for adults, and in children, the soil ingestion route is also important.  相似文献   

16.
对马尾松纯林中动物和虫生真菌群落的调查表明,植食性、捕食性、寄生性昆虫和蜘蛛类群物种数分别占51%、12%、7%和26%,益害生物个体数之比约1∶10.2个相似的林分或林间层次中,物种数、科数相等或相近,优势目相同,而且二者的植食性、捕食性、寄生性昆虫和蜘蛛类群的物种数和个体数的波动相对应地趋于一致.主成分分析显示群落1周年内处于“深秋准备越冬→冬眠→早春复苏→春、夏、初秋繁荣”的循环演替之中,其自我调节力和稳定性较强.  相似文献   

17.
The identification of meat and bone meal (MBM) as a significant factor in the spread of bovine spongiform encephalopathy (BSE) has resulted in the introduction of restrictions on the use and movement of MBM and tallow. This has led to a requirement for alternative uses for these products. This paper reports on a risk assessment performed on the use of tallow as a fuel oil extender in diesel engines. With up to 4000 tonnes of tallow being produced each year in Ireland, combustion with energy recovery represents a viable, cost-efficient utilization route. A stochastic (Latin Hypercube sampling) simulation model was developed to assess the infectiv-ity risk to humans associated with potential airborne exposure to the combustion products when using tallow as a combustion fuel in diesel engines. The model simulates the potential infectivity pathways that tallow follows, including its production from animals with potentially subclinical BSE and processing the tallow with segregation and heat treatments. The model uses probability distributions for the most important input parameters. The assessment takes into account a number of epidemiological parameters that include tissue infectivity, species barrier, disease incidence, and heat inactivation. Two scenarios, reflecting the infectivity risk in different animal tissues defined by the European Commissions Scientific Steering Committee (SSC), were performed. It is seen from the model results that the risk of a human contracting variant Creutzfeldt-Jakob Disease (vCJD) from potential airborne exposure to BSE, resulting from the combustion of tallow, is extremely small even when model uncertainty is taken into account (mean individual risk values ranging from 10-11.43 to 10-7.23 per year/person). The risks are a number of orders of magnitude less than the sporadic annual incidence level of Creutzfeldt-Jakob Disease 9CJD) in Europe (approximately 10-6)  相似文献   

18.
Chromated copper arsenate (CCA) is a chemical preservative used to treat wood for a variety of outdoor uses, including decks, fencing, and play structures. This article describes a methodology to quantify exposures to arsenic from CCA-treated wood. Exposure was evaluated for ingestion and dermal contact with arsenic-containing residue on treated wood surfaces (dislodgeable arsenic), and ingestion, dermal contact, and inhalation of soil containing arsenic originating from treated wood structures. Standard approaches were used to quantify exposures to arsenic in soil. In the absence of standard approaches for exposures to dislodgeable residue, an empirical approach was developed, extrapolating from studies of soil loadings on hands and soil ingestion rates to estimate the amount of dislodgeable residue on hands that is subsequently ingested. Results from animal studies were used to develop relative bioavailability estimates for dislodgeable and soil arsenic. A focused sensitivity analysis demonstrated that the assumptions used regarding hand loading and subsequent incidental ingestion of dislodgeable arsenic had the most significant impact on the results. This assessment indicates low uptake of arsenic into the body, resulting in incremental lifetime cancer risks within USEPA's target risk levels. We compare this approach to other methodologies used to assess exposures to treated wood.  相似文献   

19.
The need for the integration of the assessment of human and ecological risks in contaminated areas, such as derelict mines, widely increases. The risk assessment process is becoming a powerful tool to provide sound scientific bases for decision-making processes. In Portugal, the risk assessment process is in its early years and the lack of multidisciplinary teams of experts is frequently mentioned as the main obstacle to its implementation. Therefore, the majority of the reclamation actions are based on impact assessment studies that usually are characterized by few biological and toxicological considerations. In order to account for some of these constraints, the ecological risk assessment framework proposed by the U.S. Environmental Protection Agency was used to plan the assessment of human and ecological risks posed by the high concentrations of metals scattered in the vicinity of S. Domingos mine, a cuprous pyrite mine located in the Southeast Alentejo (Portugal). This study presents the problem formulation phase of the assessment. It includes all the scientific information available for the area, a conceptual model, and an analysis plan for the risk assessment process. Following a tiered approach, several tasks were planned in order to acquire chemical, toxicological, and ecological information, in order to compensate for the lack of toxicity data for site-specific species.  相似文献   

20.
In 1997, the French Ministries of the Environment and Health commissioned a detailed radioecological analysis of the Nord-Cotentin region in response to public concern about radiological risks associated with local nuclear facilities. This work was entrusted to the Groupe Radioécologie Nord-Cotentin (GRNC), a working group of experts from various origins (industrial facilities operators, public institutions, monitoring agencies, public interest and citizens groups, foreign experts). An epidemiology investigation in 1995 had reported an excess of two radiation-induced leukemia cases in an area near a nuclear reprocessing plant, a finding that attracted great interest in France, and which stimulated the need for further investigation. After the publication of its report in 1999, the GRNC was again commissioned to perform, inter alia, a corresponding assessment on the chemical releases of the local nuclear facilities. This second stage is now achieved and has revealed important similarities as well as some important differences between radiological and chemical risk assessments when applied to the specific case of the Nord-Cotentin nuclear facilities. Due to the considerable amount of work and results of the GRNC, the purpose for this article is to briefly describe the main developments of the risk assessment methodology followed by the GRNC in both cases, to detail some of the main results and to identify and explain, at each step, the similarities and the differences. The whole technical documents that support these works are available on the Internet at ?http://www.irsn.fr/nord-cotentin/?.  相似文献   

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