共查询到10条相似文献，搜索用时 125 毫秒
1.
Chapman PM 《Marine pollution bulletin》2002,44(1):7-15
Environmental toxicology has been and continues to be an important discipline (e.g., single-species testing for screening purposes). However, ecological toxicology (ecotoxicology--more realism in tests, test species and exposures) is required for predicting real world effects and for site-specific assessments. Ecotoxicology and ecology have shown similar developmental patterns over time; closer cooperation between ecologists and toxicologists would benefit both disciplines. Ecology can be incorporated into toxicology either extrinsically (separately, e.g., providing information on pre-selected test species) or intrinsically (e.g., as part of test species selection)--the latter is preferable. General guidelines for acute and chronic testing and criteria for species selection differ for ecotoxicology and environmental toxicology, and are outlined. An overall framework is proposed based on ecological risk assessment (ERA), for combining ecology and toxicology (environmental and ecological) for decision-making. Increased emphasis on ecotoxicology represents a shift from reductionist to holistic approaches. 相似文献
2.
Introduced marine organisms continue to threaten coastal resources around the world. Many agencies rely on lists of potentially harmful species for risk assessment and to prioritise management responses to an incursion. This study outlines a deductive hazard assessment technique to identify potential marine pests that may arrive via ballast water and/or hull fouling. This technique is then applied in an Australian context to identify potential "next pests" for this region. An extensive literature review identified 851 introduced marine species from around the world. The following selection criteria were then applied to develop a next pest list: (a) the species has been reported in a shipping vector or has a ship-mediated invasion history; (b) the vector still exists; (c) the species is responsible for economic or environmental harm; and, (d) it is exotic to Australia or present in Australia but subject to official control. The selection criteria are transparent and consistent with other international and national biosecurity initiatives. Thirty three of the species identified in the initial literature review satisfied all four selection criteria. These species are described here together with their associated vectors and impacts. 相似文献
3.
Yuki Chan Amy Li Singaram Gopalakrishnan Paul K.S. Shin Rudolf S.S. Wu Stephen B. Pointing Jill M.Y. Chiu 《Marine pollution bulletin》2014
Hypoxia alters the oxidation–reduction balance and the biogeochemical processes in sediments, but little is known about its impacts on the microbial community that is responsible for such processes. In this study, we investigated the effects of hypoxia and the ubiquitously dispersed flame-retardant BDE47 on the bacterial communities in marine surface sediments during a 28-days microcosm experiment. Both hypoxia and BDE47 alone significantly altered the bacterial community and reduced the species and genetic diversity. UniFrac analysis revealed that BDE47 selected certain bacterial species and resulted in major community shifts, whereas hypoxia changed the relative abundances of taxa, suggesting slower but nonetheless significant community shifts. These two stressors targeted mostly different taxa, but they both favored Bacteroidetes and suppressed Gammaproteobacteria. Importantly, the impacts of BDE47 on bacterial communities were different under hypoxic and normoxic conditions, highlighting the need to consider risk assessments for BDE47 in a broader context of interaction with hypoxia. 相似文献
4.
Brendon A. Bradley 《地震工程与结构动力学》2013,42(14):2167-2185
This paper examines the calculation of the seismic demand hazard in a practice‐oriented manner via the use of seismic response analyses at few intensity levels. The seismic demand hazard is a more robust measure for quantifying seismic performance, when seismic hazard is represented in a probabilistic format, than intensity‐based assessments, which remain prevalent in seismic design codes. It is illustrated that, for a relatively complex bridge–foundation–soil system case study, the seismic demand hazard can be estimated with sufficient accuracy using as little as three intensity measure levels that have exceedance probabilities of 50%, 10% and 2% in 50 years which are already of interest in multi‐objective performance‐based design. Compared with the conventional use of the mean demand from an intensity‐based assessment(s), it is illustrated that, for the same number of seismic response analyses, a practice‐oriented ‘approximate’ seismic demand hazard is a more accurate and precise estimate of the ‘exact’ seismic demand hazard. Direct estimation of the seismic demand hazard also provides information of seismic performance at multiple exceedance rates. Thus, it is advocated that if seismic hazard is considered in a probabilistic format, then seismic performance assessment, and acceptance criteria, should be in terms of the seismic demand hazard and not intensity‐based assessments. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
Disaster risk evolves spatially and temporally due to the combined dynamics of hazards, exposure and vulnerability. However, most previous risk assessments of natural disasters were static and typically based on historical disaster events. Dynamic risk assessments are required to effectively reduce risks and prevent future losses. Based on rainstorm disaster data and meteorological information collected in Dalian, China, from 1976 to 2015, the hidden Markov model (HMM) was used to detect inter-annual changes in rainstorm disaster risks. An independent sample test was conducted to assess the reliability of the HMM in dynamic risk assessments. The dynamic rainstorm risk in Dalian was simulated based on the observation probability matrix, which characterized the relationship dependence between rainstorm hazard and risk, and the probability matrix of state transition, which reflected the probability of changes for the risk level. High rainstorm risk was associated with high-hazard rainstorms and continuously appeared with little probability in several successive years. The reliability applied the HMM to simulate the rainstorm disaster risk was approximately 67% in the dynamic risk assessment. Additionally, the rainstorm disaster risk in Dalian is predicted to be at a medium-risk level in 2017, with a probability of 0.685. Our findings suggest that the HMM can be effectively used in the dynamic risk assessment of natural disasters. Notably, future risk levels can be predicted using the current hazard level and the HMM. 相似文献
6.
Issues in sediment toxicity and ecological risk assessment 总被引：8，自引：0，他引：8
This paper is based on a facilitated Workshop and Roundtable Discussion of key issues in sediment toxicology and ecological risk assessment (ERA) as applied to sediments that was held at the Conference on Dredged Material Management: Options and Environmental Considerations. The issues addressed included how toxicity is defined and perceived, how it is measured, and how it should be used within the context of ERA to support management decisions. The following conclusions were reached regarding scientific considerations of these issues. Toxicity is a measure of hazard and not a risk per se. Thus, toxicity testing is a means but not the end to understand risks of sediments. Toxicity testing cannot presently be replaced by chemical analyses to define hazard. Toxicity test organisms need to be appropriate to the problem being addressed, and the results put into context relative to both reference and baseline comparisons to understand hazard. Use of toxicity tests in sediment ERAs requires appropriate endpoints and risk hypotheses, considering ecological not just statistical significance, and recognizing that hazard does not equate to risk. Toxicity should be linked to population and community response to support decision-making, assessing possible genotypic adaptations that can influence risk estimates, and addressing uncertainty. Additionally, several key scientific issues were identified to improve future sediment ERAs, including the need to improve basic understanding of ecological mechanisms and processes, recognition of variability in the assessment process, and an improved focus and ability to assess risks to populations and communities. 相似文献
7.
Experience has shown that researchers and engineers are unable to construct ideal models for risk assessment and make optimal decisions in situations with insufficient data. A nonlinear risk assessment model is therefore proposed in this study based on an improved projection pursuit model (IPPM) for use in situations where insufficient data are available. A new projection index is initially proposed based on the maximum entropy principle in order to extract more information from original multidimensional data before a nonlinear risk assessment function is constructed using differential equation modeling. This function can be applied to all risk assessment problems after performing standardization and dimension reduction for the indicators. Five marine environmental risk assessment experiments for naval activity are then performed to train and validate the IPPM, as well as a traditional projection pursuit model using different numbers of training samples. The results of this analysis show that the IPPM is reliable, robust, and consistent, and can improve risk assessments by between 4.3 and 43.7% depending on performance criteria. Satisfactory results are obtained from the IPPM using just 12 training samples, and an acceptable result is still obtained if this number is reduced to just ten. Application of an IPPM therefore represents a valuable tool for risk assessment in situations where data is insufficient. 相似文献
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9.
快速有效的生物监测指标对于评估、保护、管理和恢复淡水生态系统至关重要.传统评估方法主要利用指示生物或类群的出现率和多度信息,但是忽略了水体环境中“生物”与“生物”,以及“生物”与“环境”间相互作用的复杂关系,而这些相互作用对淡水生态系统的生物多样性、生态系统服务功能以及生态系统对环境变化的响应有着深刻影响.生物共现网络是群落水平物种互作的结构模型,通过物种在群落出现及丰度数据,描述了物种间潜在的相互作用、群落的基本结构,反映群落在生态系统的功能和结构特性.生物共现网络展示了淡水生态系统中所有生物体之间潜在的相互作用关系,其拓扑结构特性可与特定的生态系统状态相关联,能够揭示生态系统的组织规律及其功能,可作为早期的、灵敏的生物指标,是一种很有应用前景的评估淡水生态系统状态和稳定性的工具. 相似文献
10.
Regional environmental risk assessment for the Nanjing Chemical Industry Park: an analysis based on information-diffusion theory 总被引：1，自引：1，他引：0
Xiaojie Meng Yan Zhang Xiangyi Yu Junhong Bai Yingying Chai Yating Li 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(8):2217-2233
A recent Chinese policy requires that all enterprises that store and use hazardous chemicals must become part of a chemical industry park. Although this reduces the environmental risk caused by the establishment of uncontrolled sites, it cannot eliminate the risk within the industrial park; on the contrary, it may exacerbate the risk. The storage and use of a wide range of hazardous chemicals in the industrial park increases both the complexity and the diversity of the environmental risk. Identification of the sources of risk will significantly affect the results of regional risk assessments. In this paper, we selected China’s Nanjing Chemical Industry Park as a case study. Based on an environmental risk assessment for every enterprise within the park, we calculated the maximum environmental risk values of each individual risk source and obtained the overall regional environmental risk values by using information-diffusion theory. The regional environmental risk value can be clustered according to the classification criteria described in this paper and depicted using a spatial partitioning map. The result can help administrative managers optimize the distribution of industrial areas and support the development of risk-prevention and -management measures. 相似文献