环境资源的量化模型及估算指标体系

本文依据区划环境标准，提出了环境资源的成本概念－环境成本。     

Is “No-Threshold” a “Non-Concept”?

A controversy prominent in scientific literature that has carried over to newspapers, magazines, and popular books is having serious social and political expressions today: “Is there, or is there not, a threshold below which exposure to a carcinogen will not induce cancer?” The distinction between establishing the existence of this threshold (which is a theoretical question) and its value (which is an experimental one) gets lost in the scientific arguments. Establishing the existence of this threshold has now become a philosophical question (and an emotional one). In this paper I qualitatively outline theoretical reasons why a threshold must exist, discuss experiments which measure thresholds on two chemicals, and describe and apply a statistical method for estimating the threshold value from exposure-response data.     

Adversarial safety analysis: borrowing the methods of security vulnerability assessments

INTRODUCTION: Safety and security share numerous attributes. The author, who heads the (Security) Vulnerability Assessment Team at Los Alamos National Laboratory, therefore argues that techniques used to optimize security might be useful for optimizing safety. OPTIMIZING SECURITY: There are three main ways to attempt to improve security-security surveys, risk assessment (or "design basis threat"), and vulnerability assessments. The latter is usually the most effective. SAFETY ANALOGS: Vulnerability assessment techniques used to improve security can be applied to safety analysis--even though safety is not ordinarily viewed as having malicious adversaries (other than hazards involving deliberate sabotage). Thinking like a malicious adversary can nevertheless have benefits in identifying safety vulnerabilities. SUGGESTIONS: The attributes of an effective safety vulnerability assessment are discussed, and recommendations are offered for how such an adversarial assessment might work. CONCLUSION: A safety vulnerability assessment can potentially provide new insights, a fresh and vivid perspective on safety hazards, and increased safety awareness.     

Assessment of contamination by heavy metals and petroleum hydrocarbons in sediments of Montevideo Harbour (Uruguay)

As part of the first environmental assessment within Montevideo Harbour, in summer and winter of 1998, sediments samples were collected at eight locations to determine the spatial distribution of anthropogenic pollutants. Muddy sediments with high organic matter content dominate the study area. Heavy metal levels indicated that sediments were highly polluted with Zn (overall mean: 312+/-102 microg g(-1) dry sediment), Pb (85+/-31), Cu (89+/-25), Cr (162+/-62), and Hg (0.63+/-0.3) and moderately with Ni (30+/-2) and Ag (1.2+/-0.4). Depending on location and season, aliphatic hydrocarbons reached from 21 to 120 microg g(-1), while the unresolved complex mixture represented up to 76% of the total aliphatic fraction. Total PAH concentrations ranged from 1.56 to 90.44 microg g(-1); except at one location, petroleum derivatives were identified as main local source. The results pointed out that almost all the harbour area presented some substances that can cause adverse biological effects, especially in the inner region where all metals are above PEL levels. Principal components analysis confirmed that the inner harbour region is most severely affected by the pollutants and it was possible to differentiate three regions according to their environmental quality.     

Health risk assessment of PCDD/F emissions from a hazardous and medical waste incinerator in Turkey

A multimedia risk assessment procedure was conducted to determine the fate and transport of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emissions from the Izmit Hazardous and Medical Waste Incinerator (IZAYDAS) in Turkey and their potential health risks. Congener concentrations in ambient air and their deposition rates were determined by an air dispersion model (ISCST3). Their transfer to some plant groups and animal tissues was predicted by food chain modeling. Exposure scenarios were produced based on three receptor groups (urban, semiurban, and rural) and five subgroups determined according to ages. Daily intakes of PCDD/Fs via exposure pathways were determined based on three different emission scenarios for each group and subgroup. Estimated incremental PCDD/F doses caused by the incinerator emissions in central-tendency scenario were computed as between 2.31 x 10(-6) and 0.008 pg TEQ kg(-1) bodyweight (bw) day(-1) on average for all the receptors other than infants in all the settings, while the range was 3.01 x 10(-5)-0.081 pg TEQ kg(-1) bw day(-1) for infants. Sensitivity analysis showed that the consumption of vegetal products and their locally grown fractions are the most significant parameters in the exposure to PCDD/Fs in the area.     

The ecological effects of trichloroacetic acid in the environment

Trichloroacetic acid (TCAA) is a member of the family of compounds known as chloroacetic acids, which includes mono-, di- and trichloroacetic acid. The significant property these compounds share is that they are all phytotoxic. TCAA once was widely used as a potent herbicide. However, long after TCAA's use as a herbicide was discontinued, its presence is still detected in the environment in various compartments. Methods for quantifying TCAA in aqueous and solid samples are summarized. Concentrations in various environmental compartments are presented, with a discussion of the possible formation of TCAA through natural processes. Concentrations of TCAA found to be toxic to aquatic and terrestrial organisms in laboratory and field studies were compiled and used to estimate risk quotients for soil and surface waters. TCAA levels in most water bodies not directly affected by point sources appear to be well below toxicity levels for the most sensitive aquatic organisms. Given the phytotoxicity of TCAA, aquatic plants and phytoplankton would be the aquatic species to monitor for potential effects. Given the concentrations of TCAA measured in various soils, there appears to be a risk to terrestrial organisms. Soil uptake of TCAA by plants has been shown to be rapid. Also, combined uptake of TCAA from soil and directly from the atmosphere has been shown. Therefore, risk quotients derived from soil exposure may underestimate the risk TCAA poses to plants. Moreover, TCE and TCA have been shown to be taken up by plants and converted to TCAA, thus leading to an additional exposure route. Mono- and di-chloroacetic acids can co-occur with TCAA in the atmosphere and soil and are more phytotoxic than TCAA. The cumulative effects of TCAA and compounds with similar toxic effects found in air and soil must be considered in subsequent terrestrial ecosystem risk assessments.     

Rough Set Rule Induction for Suitability Assessment

The data that characterize an environmental system are a fundamental part of an environmental decision-support system. However, obtaining complete and consistent data sets for regional studies can be difficult. Data sets are often available only for small study areas within the region, whereas the data themselves contain uncertainty because of system complexity, differences in methodology, or data collection errors. This paper presents rough-set rule induction as one way to deal with data uncertainty while creating predictive if–then rules that generalize data values to the entire region. The approach is illustrated by determining the crop suitability of 14 crops for the agricultural soils of the Willamette River Basin, Oregon, USA. To implement this method, environmental and crop yield data were spatially related to individual soil units, forming the examples needed for the rule induction process. Next, four learning algorithms were defined by using different subsets of environmental attributes. ROSETTA, a software system for rough set analysis, was then used to generate rules using each algorithm. Cross-validation analysis showed that all crops had at least one algorithm with an accuracy rate greater than 68%. After selecting a preferred algorithm, the induced classifier was used to predict the crop suitability of each crop for the unclassified soils. The results suggest that rough set rule induction is a useful method for data generalization and suitability analysis.     

Assessing Biological Integrity Using Freshwater Fish and Decapod Habitat Selection Functions

Comparison between the number of taxa observed and the number expected in the absence of human impact is an easily understood and ecologically meaningful measure of biological integrity. This approach has been successfully applied to the assessment of the biological quality of flowing water sites using macroinvertebrates with the river invertebrate and classification system (RIVPACS) and its derivatives. In this paper, we develop a method similar to the RIVPACS predictive model approach to assess biological integrity at flowing-water sites using freshwater fish and decapod assemblages. We extend the RIVPACS approach by avoiding the biotic classification step and model each of the individual species separately. These assemblages were sampled at 118 least impacted (reference) sites in the Auckland region, New Zealand. Individual discriminant models based on the presence or absence of the 12 most common fish and decapod species were developed. Using the models, predictions were made using environmental measures at new sites to yield the probability of the capture of each of the 12 species, and these were combined to predict the assemblage expected at sites. The expected assemblage was compared to that observed using an observed over expected ratio (O/E). The models were evaluated using a number of internal tests including jackknifing, data partitioning, and the degree to which O/E values differed between reference sites and a set of sites perceived to be impaired by human impacts.     

景观生态学在建设项目生态环境影响评价中的应用

景观生态学目前是国家环境保护总局《非污染生态影响评价技术导则》引入的概念框架和理论方法。本文通过景观生态学在不同性质建设项目中的运用分析,进行了一定的尝试,更加希望在今后建设项目生态环境影响评价工作中得到修正和完善。     

River systems as providers of goods and services: a basis for comparing desired and undesired effects of large dam projects

In developing countries, large dam projects continue to be launched, primarily to secure a time-stable freshwater supply and to generate hydropower. Meanwhile, calls for environmentally sustainable development put pressure on the dam-building industry to integrate ecological concerns in project planning and decision-making. Such integration requires environmental impact statements (EISs) that can communicate the societal implications of the ecological effects in terms that are understandable and useful to planners and decision-makers. The purpose of this study is to develop a basic framework for assessing the societal implications of the river ecological effects expected of a proposed large dam project. The aim is to facilitate a comparison of desired and potential undesired effects on-site and downstream. The study involves two main tasks: to identify key river goods and services that a river system may provide, and to analyze how the implementation of a large dam project may alter the on-site capacity and downstream potentials to derive river goods and services from the river system. Three river goods and six river services are identified. River goods are defined as extractable partly man-made products and river services as naturally sustained processes. By four main types of flow manipulations, a large dam project improves the on-site capacity to derive desired river goods, but simultaneously threatens the provision of desirable river goods and services downstream. However, by adjusting the site, design, and operational schedule of the proposed dam project, undesirable effects on river goods and services can be minimized.