A note on environmental risk and the rate of discount: Comment

The sign of the adjustment to the riskless discount rate for environmental risk depends on whether the price of avoiding the consequences of the externality is seen as reducing expected net benefits or increasing expected costs. The conclusion is that the risk adjustment is positive when the externality is defined as reducing expected net benefits.     

A note on optimal taxation of environmental spillovers

This note addresses the question of what policy the government should adopt when industrial pollution can be reduced partially by the imposition of effluent taxes and partially by a publicly operated waste treatment plant.In the case of increasing returns to public abatement, an effluent tax set at marginal user cost will not generate enough revenue to finance the facility. The key issue is that of finding additional revenue the most efficiently. Here, this question is dealt with in the framework of commodity taxation, with consideration given to the possibility that both effluent and commodity taxes derived on efficiency grounds might be quite regressive.     

A note on data augmentation and iterative simulation for survival rate estimation

In this paper we examine the use of data augmentation techniques for simplifying iterative simulation in the context of both Bayesian and classical statistical inference for survival rate estimation. We examine two distinct model families common in population ecology to illustrate our ideas, ring-recovery models and capture–recapture models, and we present the computational advantage of this approach. We discuss also the fact that problems associated with identifiability in the classical framework can be overcome using data augmentation, but highlight the dangers in doing so under both inferential paradigms.

How certain are we about the certainty-equivalent long term social discount rate?

Theoretical arguments for using a term structure of social discount rates (SDR) that declines with the time horizon have influenced government guidelines in the US and Europe. The certainty equivalent discount rate that often underpins this guidance embodies uncertainty in the primitives of the SDR, such as growth. For distant time horizons the probability distributions of these primitives are ambiguous and the certainty equivalent itself is uncertain. Yet, if a limited set of characteristics of the unknown probability distributions can be agreed upon, ‘sharp’ upper and lower bounds can be defined for the certainty-equivalent SDR. Unfortunately, even with considerable agreement on these features, these bounds are widely spread for horizons beyond 75 years. So while estimates of the present value of intergenerational impacts, including the social cost of carbon, can be bounded in the presence of this ambiguity, they typically remain so imprecise as to provide little practical guidance.     

Evidence of variable discount rates and non-standard discounting in mortality risk valuation

Time discounting is central to the valuation of future health and mortality risks in public sector allocative decision-making, particularly for environmental policies with delayed health impacts. Using a Risk-Risk trade-off survey, we elicit discount rates for fatality risks and establish discounting functional forms on both a sample and an individual level. We find wide variation in implicit discount rates for fatality risk between individuals, as well as between-individual heterogeneity in discounting functional forms. In aggregate, the sample is best characterised by subadditive discounting. Our work has implications for the academic investigation of intertemporal choice involving mortality risks, and potentially for the evaluation of policy options with delayed mortality risk outcomes. A thought experiment cautions against the standard practice of assuming that exponential discounting characterises society's time preferences.     

Genetic and environmental effects on the growth rate of Littorina saxatilis

Transfer experiments with two morphs of Littorina saxatilis Olivi (=L. rudis) typically inhabiting exposed and sheltered localities, showed a between-morph difference in shell growth in the same type of habitat, and a withinmorph difference between exposed and sheltered environments. The former indicates a genetic difference between the two morphs, although growth rate has an environmental component as shown by the latter. Juvenile snails of the exposed morph were on average slightly larger than sheltered morph juveniles on hatching, but at 20 wk, when raised in identical environments, the sheltered morph juveniles had grown significantly larger than the exposed ones. A rise in temperature from 5° to 10°C enhanced growth rate for snails raised in the laboratory. Temperature alone could not however explain increased growth during the spring and summer in natural populations.     

环境风险知觉和评价的整体框架

环境风险通常发生在一定时间之后,以某种可能性发生在某个特定的地方,使得某些人群受到影响。因此,环境风险是典型的多维度事件,它涵盖四个基本的偏好维度：时间、空间、概率与社会性,每个维度都可能导致环境风险知觉和评价出现折扣（discount）现象。但是,传统视角往往关注单一维度,主要是时间,因而割裂了维度的整体性。基于环境风险的多维度特征,提出了一个统一的多维度偏好框架,为环境风险知觉及评价提供整体性视角。这四个偏好维度统一的内在原因是心理距离。维度共性意味着时间维度上的折现机制能够应用到其它维度,为此,对环境风险跨期评价中关于折现率热点问题的研究进展进行了一个关键的梳理。未来有必要在此整体框架下,重点关注三个方面的问题：（1）环境折现率,对环境折现率的要素及其关系进行规范性分析,进而分析环境贴现率与经济贴现率之间的关系,及双率折现对可持续发展的涵义;（2）基于维度共性,将时间维度上的研究结论应用到其它维度;（3）研究多重维度复合情形下的偏好和评价问题,建立综合性描述模型,依托具体案例探讨有效的环境风险沟通策略、环境政策和制度设计。     

A note on the use of property values in estimating marginal willingness to pay for environmental quality

The principle purpose of this paper is to discuss the theoretical background of the use of property values in estimating damage function. In the first part of the paper a general equilibrium model is constructed in which environmental quality differences are capitalized into land rents. In the second part of the paper some of the assumptions needed for this result are scrutinized, and it is found that they are hardly realistic. The main conclusion is, thus, that the study of property values cannot give viable estimates of the marginal willingness to pay for environmental quality.     

Understanding and addressing the environmental risk of microplastics

Over the past decades, the plastic production has been dramatically increased. Indeed, a category of small plastic particles mainly with the shapes of fragments, fibers, or spheres, called microplastics (particles smaller than 5 mm) and nanoplastics (particles smaller than 1 μm) have attracted particular attention. Because of its wide distribution in the environment and potential adverse effects to animal and human, microplastic pollution has been reported as a serious environment problem receiving increased attention in recent years. As one of the commonly detected emerging contaminants in the environment, recent evidence indicates that the concentration of microplastics show an increasing trend, for the reason that up to 12.7 million metric tons of plastic litter is released into aquatic environment from land-based sources each year. Furthermore, microplastic exposure levels of model organisms in laboratory studies are usually several orders of magnitude higher than those found in environment, and the microplastics exposure conditions are also different with those observed in the environment. Additionally, the detection of microplastics in feces indicates that they can be excreted out of the bodies of animal and human. Hence, great uncertainties might exist in microplastics exposure and health risk assessment based on current studies, which might be exaggerated. Policies reduce microplastic emission sources and hence minimize their environmental risks are determined. To promote the above policies, we must first overcome the technical obstacles of detecting microplastics in various samples.     

A note on the allocation of investment

It is shown by example that the results obtained by Gruver [11 concerning specialization of investment in either directly productive or pollution control capital arise because of an implicit linearity assumption on the underlying technology. Utilizing a strictly concave “eighth sphere” technology, results are obtained which imply joint investment in the two types of capital except in “rare” instances. The results indicate the need for incorporating more general technologies into the analysis of such problems.     

A review on environmental distributions and risk management of phenols pertaining to the endocrine disrupting chemicals in Taiwan

Some phenols, including pentachlorophenol, dichlorophenol, alkylphenols (nonylphenol & octylphenol) and bisphenol-A, have been identified as endocrine disrupting chemicals (EDCs). These phenolic EDCs are extensively used in a wide range of household products, thus posing potential health risks for humans exposed to them. From the viewpoints of ecotoxicology, human health and regulations, it is urgent to restrict the emissions and releases of these estrogenic chemicals from the industrial processes and commercial products. This review article first focused on the physicochemical properties of phenolic EDCs and their industrial/commercial uses. Furthermore, their environmental distributions and regulatory frameworks for integrated risk management of these chemicals in Taiwan were conducted as a case study. Emphasis was thus put on the cross-ministerial joint venture (i.e., environment, health, agriculture, labor, and industry authorities), and the government policy on the risk management of EDCs. Finally, some recommendations for pollution prevention and toxicity reduction of phenolic EDCs were also addressed and analyzed to progress towards a sustainable society in Taiwan.     

A note on the feeding of Calanus helgolandicus on detritus

Experiments on the feeding of Calanus helgolandicus females on detrital material were carried out. Natural detritus from the ocean was never ingested, whereas dead diatoms were readily eaten. Furthermore, it was shown that C. helgolandicus females ingested large amounts of fecal material produced by the same species in other vessels. These results indicate that the copepod C. helgolandicus feeds not only on living organisms, but also on dead particles.     

A note on natural production functions

Two techniques are presented for estimation of natural animal populations, both of which may incorporate the effect of pollutants on populations. Both techniques assume specific underlying population dynamics which may not be applicable to certain species or ecosystems. However, both techniques allow for testing the hypothesis that the population dynamics specified is applicable. The techniques are used to criticize two recent empirical investigations of fisheries.     

Addressing the environmental risk of persistent organic pollutants in China

The Stockholm Convention on persistent organic pollutants (POPs) was adopted in 2001. This year is the 10th anniversary of the adoption of the Convention. Until now, 22 chemicals or chemical categories have been listed as POPs in the Stockholm Convention. The POPs Research Center was established in Tsinghua University in the same year when the Convention was adopted. In the last ten years, much work has been done by Chinese researchers to understand the environmental risk of POPs in China. This article aims to review the recent research progress of our POPs Research Center and some other Chinese researchers?? studies in addressing the environmental risk of POPs, including the priority screening and inventory study of POPs, monitoring and modeling of POPs pollution and exposure, and environmental risk assessment and modeling of POPs. Although great advances in addressing the environmental risk of POPs have been made in recent years, we are still facing quite a few problems, such as data scarcity and uncertainty in environmental risk assessment of POPs. The study on the effect of POPs mixtures is in its infancy and currently POPs are usually assessed from legal perspective by risk assessment of single chemicals. These problems should be well addressed by further efforts. Further studies should also be taken in future to study environment risk of POPs by considering aspects of coupled dynamics between climate processes and POPs. Such sound scientific, riskbased information can support decision-making aiming to effectively minimize the risk level of POPs.     

A note on the sufficiency of low resolution ecosystem models

Analysis of a system of non-linear differential equations illustrates the effects of interactions between biotic and abiotic components of a complex aquatic ecosystem model. A stochastic analysis shows that the variance of the abiotic variables is related in a simple manner to the autocorrelation function of the biotic variables. The results suggest that for oligotrophic and eutrophic conditions, relatively simple ecosystem models may be sufficient for studies of an aquatic environment. Under mesotrophic conditions, the high state variable resolution of a complex model may be necessary.     

A note on the development of the thermocline in temperate lakes

An exact solution has been obtained for a non-linear partial differential equation governing the vertical transport of heat in a lake. The equation, derived and analyzed numerically by Sundaram and Rehm (1971, 1973) is based on a balance between thermal buoyany forces and wind induced turbulence. The exact solution displays the qualitative features of the numerical solution and its representation of the seasonal descent of the thermocline is accurate.     

A note on the welfare-economic consequences of extended fishing limits

A standard two countries-two commodities model is developed to consider the gains in efficiency resulting from transferring common property fish stocks to the jurisdiction of coastal states attempting to reach allocative efficiency. As a result of this transfer, the long-term catch from seriously overexploited fish stocks will be greater than otherwise, causing the price of fish to fall. This will transfer some, and possibly all, of the gains from more efficient fishing to fish consumers in the rest of the world. The note concludes with some remarks on the plausibility of the assumption that governments will pursue allocative efficiency.     

A method to determine the protection zone of chemical industrial park considering air quality,health risk and environmental risk: a case study

Environmental Geochemistry and Health - In China, chemical enterprises are required to cluster into a large number of chemical industrial parks (CIPs), which increase risks and threats to the...     

三种药品联合毒性作用及其环境风险分析

测定了阿司匹林、盐酸环丙沙星和阿奇霉素3种常见活性医药成分(APIs)对发光菌的单一毒性以及混合体系的联合毒性,并应用毒性单位法(TU)、相加指数法(AI)和混合毒性指数(MTI)等方法对混合体系联合作用类型进行分析.结果表明,阿司匹林显示较高的单一毒性,联合毒性中除阿司匹林-环丙沙星二元混合体系为部分相加作用外,其它体系联合毒性均呈现为不同程度的拮抗作用.同时应用简化环境模型计算了3种医药品的预测环境浓度(PEC)和预测无效应浓度(PNEC),将风险表征参数(PEC/PNEC)作为综合评价因子,获得3种医药品目前在大连开发区污水处理厂排水中的数值较低,以阿司匹林综合评价因子最高.