Outdoor background ELF magnetic fields in an urban environment

Classification of 'exposed/non-exposed' subjects in epidemiological studies concerning the possible cancer risk associated with ELF magnetic field exposure is based on the a priori assumption of magnetic field value cut-off points that, often, are defined equal to minimum exposure levels typical of a population residing near high voltage facilities (0.1-4.2 microT), but in some cases an environmental magnetic field level not associated with transmission lines can exist. The results of an ELF magnetic field survey in an Italian urban area (about 1 million inhabitants) are presented: average field levels are correlated with population density of different districts. Exposure indexes are obtained, which are compared with those evaluated in studies regarding domestic exposure: background average levels result in comparable to cut-off points in epidemiological studies, but in some districts with high population density, they are much higher. This shows that knowledge of background magnetic field level in urban areas can assume a significant role in exposure assessment.     

Assessment of ELF magnetic fields produced by independent power lines

In this paper, the problem of assessing the ELF (extremely low-frequency) magnetic fields produced, in a certain area characterised by the presence of more than one independent power line, is faced. The use of the incoherent summation of the single contributions, as an advantageous estimator of the total magnetic field, is proposed and justified by means of a heuristic procedure. This kind of approach can be seen as a useful and practical tool to be employed in environmental impact analysis and in assessing long-term human exposure to ELF magnetic fields.     

Influence of probe size on the measurement accuracy of non-uniform ELF magnetic fields

The accuracy of extremely low frequency (ELF) magnetic field measurements can be sensitively varied by the meter probe size when the spatial distribution of the magnetic flux density is highly non-uniform, e.g. if the measurement point is close to the field source. The deviation between measured and actual field varies from point to point depending on the probe dimension and on the source configuration, once the other measurement conditions are fixed. The analysis of this effect is developed through a two-dimensional numerical model that enables the evaluation of the actual field value and of the corresponding probe indication. The error distribution, i.e. the deviation between actual and measured value, is computed for magnetic fields generated by industrial three-phase systems under both balanced and unbalanced supply conditions. The analysis shows how, for a given source, the error depends not simply on the distance from the source in relation to the probe size, but on its spatial distribution, which is complex and cannot be a priori predicted without using a computational tool such as the one proposed.     

The boundary element modelling of the human body exposed to the ELF electromagnetic fields

In this paper a cylindrical model of human body exposed to the extremely low frequency (ELF) electromagnetic field is presented. The analysis is based on the solution of the simplified integral equation for thick wires. The numerical solution of the integral equations is performed by the Galerkin–Bubnov variant of the boundary element method. Several numerical results for the ELF exposures are presented.     

Landfarming operation of oily sludge in arid region--human health risk assessment

Landfarming is becoming one of the most preferred treatment technologies for oily sludge disposal in the Arabian Gulf region in general, and in the Kingdom of Saudi Arabia in particular. This technology is considered to be, economical, energy efficient, and environmentally friendly with minimal residue disposal problems. Application of this technology in the region is simply based on the studies conducted in the United States of America and Europe. There have hardly been any scientific studies conducted to evaluate performance of landfarming technology under arid conditions. Recently, detailed field experimental study has been conducted to evaluate the degradation process and health risk issues in landfarming under arid conditions. The study observed volatilization as the main process of hydrocarbon degradation, which can cause significantly high concentration of airborne volatile organic compounds (VOCs) in the atmosphere leading to serious human health risk to the onsite workers. It is particularly true in the early phase of the landfarming process (first 2 months from initial loading). This paper elaborates these findings in detail.     

Public understanding of risk in health impact assessment: a psychosocial approach

Development projects inevitably pose risks to the health of humans and the planet. Health impact assessment (HIA) practitioners increasingly evaluate the mental health effects of development but have rarely considered those caused by public understanding of risk (‘risk perception’) itself a determinant of health. This paper proposes a new psychosocial model of public understanding of risk in response to the literature on perceived high risk developments. It exemplifies the psychosocial process that occurs when people respond to industrial threats to health. In doing this, it draws upon literature from psychology, social science and public health. The model is foregrounded in the context of psychosocial health in HIA. The paper also reviews the health and well-being effects that may result. Overall, it is argued that the philosophical and moral underpinnings of HIA compel practitioners and developers to understand the formation and ongoing development of public understandings of risk in light of the cultural, demographic, temporal and other contextual factors shaping them in unique development contexts where HIAs are undertaken, and how understandings of risk actually affect community health. We encourage them to propose mitigation measures and solutions that accord with the values of Planetary Health.     

Probabilistic risk assessment of HTGRs

Probabilistic risk assessment (PRA) methods have been applied to gas-cooled reactors for more than a decade and to HTGRs for more than six years in the programmes sponsored by the US Department of Energy. Significant advancements to the development of PRA methodology in these programmes are summarized as are the specific applications of the methods to HTGRs. Emphasis here is on PRA as a tool for evaluating HTGR design options. Current work and future directions are also discussed.     

Site-specific health risk assessment of dioxins and furans in an industrial region with numerous emission sources

While the sources of releasing dioxins have received much attention, the health risks of incinerators are studied considerably more than those of other sources, such as metallurgical industry. Furthermore, risk assessments focus primarily on the effects of single sources; few have addressed the aggregate risks from multiple sources in a region. When many sources of dioxins exist in an area, such as the Industrial Park located in the densely populated district—Siaogang District in southern Taiwan where 17 primary known PCDD/F stationary emission sources are clustered, is the aggregate exposure to these sources imposing high risks even though individual sources comply with emission standards? The study combined the multimedia and multiple pathway exposure modeling and site-specific exposure scenario to assess dioxin risks contributed by the 17 emission sources in the District, including municipal waste incinerators, medical waste incinerators, sinter plants, electric arc furnace, secondary aluminum smelters, cement kilns, etc. The average cancer risk of a resident living in the District was found to be 3.43E−04 under the site-specific exposure scenario. The top emission source is the sinter plant, followed by the electric arc furnace. The information has driven the local government to conduct more complete assessment and at the same time to consider enforcing a stricter local standard of dioxin emissions in the Siaogang District.     

Uncertainty in probabilistic risk assessment

Dealing with uncertainty is an important and difficult aspect of analyses for complex systems. Such systems involve many uncertainties, and assessing probabilities to represent these uncertainties is itself a complex undertaking utilizing a variety of information sources. At a very basic level, uncertainty is uncertainty, and attempting to distinguish between ‘types of uncertainty’ is questionable. At a practical level, on the other hand, a close look at such distinctions suggests that they are driven by important modelling issues related to model structuring, probability assessment, information gathering, and sensitivity analysis. Anything that brings more attention to these issues should improve the state of the art. However, I would prefer to attack the issues directly instead of working indirectly through the notion of ‘types of uncertainty.’     

Earthquake risk assessment of building structures

During the past two decades, probabilistic risk analysis tools have been applied to assess the performance of new and existing building structural systems. Structural design and evaluation of buildings and other facilities with regard to their ability to withstand the effects of earthquakes requires special considerations that are not normally a part of such evaluations for other occupancy, service and environmental loads. This paper reviews some of these special considerations, specifically as they pertain to probability-based codified design and reliability-based condition assessment of existing buildings. Difficulties experienced in implementing probability-based limit states design criteria for earthquake are summarized. Comparisons of predicted and observed building damage highlight the limitations of using current deterministic approaches for post-earthquake building condition assessment. The importance of inherent randomness and modeling uncertainty in forecasting building performance is examined through a building fragility assessment of a steel frame with welded connections that was damaged during the Northridge Earthquake of 1994. The prospects for future improvements in earthquake-resistant design procedures based on a more rational probability-based treatment of uncertainty are examined.     

风险评估技术的选择

选择合适的风险评估技术和方法,有助于组织及时高效地获取准确的评估结果.在实践中,风险评估活动的复杂及详细程度千差万别.风险评估的形式及结果应与组织的自身情况适合,并在明确环境信息时确定.     

Multi-attribute risk assessment for risk ranking of natural gas pipelines

The paper presents a decision model for risk assessment and for risk ranking of sections of natural gas pipelines based on multi-attribute utility theory. Pipeline hazard scenarios are surveyed and the reasons for a risk assessment model based on a multi-attribute approach are presented. Three dimensions of impact and the need to translate decision-makers’ preferences into risk management decisions are highlighted. The model approaches these factors by using a multi-attribute utility function, in order to produce multi-dimensional risk measurements. By using decision analysis concepts, this model quantitatively incorporates the decision-maker's preferences and behavior regarding risk within clear and consistent risk measurements. In order to support the prioritizing of critical sections of pipeline in natural gas companies, this multi-attribute model also allows sections of pipeline to be ranked into a risk hierarchy. A numerical application based on a real case study was undertaken so that the effectiveness of the decision model could be verified.     

Development of a multi-pathway probabilistic health risk assessment model for swimmers exposed to chloroform in indoor swimming pools

For swimmers, exposure to chloroform, a probable carcinogen, in indoor swimming pools can be through different pathways such as ingestion, dermal absorption, inhalation during swimming, and inhalation during resting. In order to evaluate health risk results from excessive exposure to chloroform, concentrations of chloroform in pool water were first collected and analyzed. Then, a two-layer model is used, which is capable of estimating the concentrations of chloroform in the boundary layer adjacent to the water surface and the concentrations of chloroform in indoor swimming pool air. The use of stratification model is important for estimating the risks for swimmers since they are exposed to these kinds of situations while performing swimming and resting in indoor swimming pools environment. The incremental lifetime cancer risk (ILCR) was then estimated using the multi-pathway exposure model. The results showed that the 95th percentile of ILCRs calculated for male and female swimmers were 2.80 × 10(-4) and 2.47 × 10(-4), respectively. The major exposure routes were found to be inhalation during swimming which contributes to more than 99% of the total health risk. Our study suggested that to protect swimmers from excessive exposure to chloroform, alternative methods or processes of disinfection should be considered for swimming pool managers.     

Uncertainty in health risk analysis

This paper discuss several quantitative issues that arise in the analysis of health risks, beginning with principles such as de minimis and zero-risk. The paper also provides a probabilistic definition of risk in terms of hazard, context, consequence, magnitude, and uncertainty. The example relies on this definition to investigate, through sensitivity analysis, the effect that uncertainty has on the results obtained. The results, from a case study based on waterborne total arsenic, show that the choice of dose—response functions causes more uncertainty than any other component of risk analysis. Chemical carcinogenesis provides the basis for discussing inability to know as well as uncertainty. The conclusion is that risk analysis keeps uncertainty and inability to know separate; through this function, it provides a much needed method to present information to decision makers and the public.     

Meaning and contextualisation in risk assessment

This paper presents an analysis of the construction of risk as a social process. It provides a critique of Jasanoff's ‘two cultures’ model of the risk assessment community, arguing that corresponding rhetorics serve to obscure the hybrid nature of risk. It is argued that a new perspective, based on the contextualisation of expert scientific knowledge is needed, which transcends reductionist tendencies that view risk assessment as simply about either material artefacts or social constructions. Such approaches have the potential, it is suggested, to address not only the complexity but also the moral and political dilemmas associated with a wide range of risk management problems.     

Constrained noninformative priors in risk assessment

A constrained noninformative prior distribution, a generalization of the Jeffreys noninformative prior, is defined for a single unknown parameter as the distribution corresponding to the maximum entropy distribution, subject to the assumed constraint(s), in the transformed model where the unknown parameter is approximately a location parameter. This note illustrates this idea with binomial and Poisson data models, and gives an example from risk assessment showing the practical usefulness of the constrained noninformative prior.     

信息安全风险评估方法的应用

信息安全风险评估,是依据信息安全技术与管理标准,对信息系统及由其处理、传输和存储的信息的机密性,完整性和可用性等安全属性进行风险评价和控制的过程.