An Iterative Choice Approach to Valuing Clean Lakes,Rivers, and Streams

This article introduces an iterative choice procedure for valuing inland water quality. This approach breaks up the valuation into a series of component tasks. The water quality ladder approach is not valid empirically. Consequently, respondents in Colorado and North Carolina assessed the value of making water quality rated good by EPA, which has a value of $22.40 per additional percent improvement. Nonuse and probabilistic use are highly valued. The results also indicate how water quality valuations differ for aquatic environment, edible fish, and swimming, as well as for water that is cloudy, smelly, or polluted by toxics. Minorities are particularly likely to rely upon monitorable water quality attributes.     

Major Sources of Exposure to Benzene and Other Volatile Organic Chemicals1,2

The major sources of human exposure to about a dozen volatile organic chemicals (VOCs) have recently been identified.¹ For nearly every chemical, the major sources of exposure are completely different from the major sources of emissions. This finding implies that current environmental regulations and control strategies are misdirected. Important sources of exposure are typically not regulated in any way, whereas unimportant sources are heavily regulated. Vast sums of money are spent on problems involving little risk (e.g., hazardous waste sites), whereas few resources are expended on problems involving higher risk (e.g., indoor air pollution). The following paper summarizes recent findings regarding major sources of exposure to several VOCs. Benzene is selected as a case study. Brief discussions of tetrachloroethylene and paradichlorobenzene are also included.     

公众社区参与意愿对危化品危害利益相关者感知的影响

面对危化品危害,政府及相关单位面临着日益严峻的既要保证公众知情,又要避免信息过度传播的难题,信任是导致这种沟通困境的重要因素。为解决危害信息有效沟通问题,从重构公众与政府之间信任关系的角度入手,以公众利益相关者感知衡量信任,探究公众社区参与意愿对利益相关者感知的影响关系,并将社区参与分为代表单向沟通的仪式性参与和代表双向沟通的实质性参与。研究结果表明:公众社区参与意愿有利于提升公众危化品危害利益相关者感知,特别是仪式性参与意愿的直接作用效果更为显著;实质性参与意愿和危害利益相关者感知的关系中,预决策过程起到完全中介的作用;危化品危害知识在社区参与意愿和利益相关者感知的影响关系中起到显著的正向调节作用,特别是在预决策过程与利益相关者感知的影响路径中。研究结论为构建公众和政府之间的信任关系,进而为缓解危化品危害信息沟通难题提供理论支撑和实践价值。     

精细化学品化学教学改革探讨

为培养理论一应用复合型人才，适应市场经济发展的要求，精细化学品化学教学内容和教学方法必须进行相应的改革。这一改革应根据精细化学品化学的特点，同时重视发挥教师的关键性作用。     

基于修正C-D函数模型的技术进步与经济增长测算——以甘肃省为例

利用修正的生产函数较好地估计了甘肃省资本、劳动和技术进步对经济产出的贡献份额。结果显示,资本投入对经济产出贡献较大,技术进步对经济产出效果不理想,而劳动对产出贡献处于较低水平,经济发展主要依靠资本高投入带动,经济发展还处于粗放式阶段,这种模式是不可持续的。为了可持续发展,必须提高要素转化效率,提高劳动者素质和职业技能。     

农户农用化学品减施意愿及影响因素研究——基于山东省H镇208份菜农问卷调查的实证

减少农用化学品投入对减轻农业生态环境污染、保障农产品质量安全和促进农业可持续发展具有重要意义。基于山东省H镇208份菜农的调查问卷数据,依托成本收益和生产要素理论,采用Logistic模型实证分析菜农农用化学品减施意愿及影响因素。结果表明:54.33%的农户愿意减少农用化学品投入;影响因素方面,农户年龄在5%的水平下有显著的负向影响,受教育程度、农药残留认知和化肥过量施用导致重金属污染的认知分别在5%、1%和5%的水平下有显著的正向影响;农用化学品年投入成本和农药每公顷平均花费对农户农用化学品减施意愿的影响并不显著,但模型系数均为正,表明这些变量对农户减少农用化学品投入具有一定程度上的正效应。最后,基于研究结论分别从政府、农资经销商和农户角度提出相关政策建议。     

我国《化学物质控制法》之立法展望——兼论欧盟之经验

目前,我国的化学物质立法缺乏一部基本立法,在国际贸易自由化和环境问题全球化的今天,已经不能适应促进我国化学物质国际贸易和国际环境保护的需要,必须予以关注。我国《化学物质控制法》应当借鉴欧盟的立法经验,以有毒有害的现有化学物质和新化学物质为主要的调整对象,以化学物质的安全、环境风险预防和控制为主要的规范领域。只有这样,才能体现其立法价值。     

Computerized Estimates of Potential Occupational Health Risk Due to Chemical Exposure

Estimating the potential health risk encountered by workers due to their exposure to various chemicals is enormously complex, since many chemicals be involved and each may have multiple toxic effects. As an aid to this estimation process, a computer program, or model, which computes index numbers expressing the relative health risk of occupational groups due to their potential chemical exposures was developed at the National Institute for Occupational Safety and Health (NIOSH). This model considers an inventory of the chemicals to which specific occupational groups are potentially exposed, the published information regarding the toxic effects of each chemical, and the conditions of occupational exposure. The system then develops indices of potential occupational group health risk by considering weighted combinations of eight distinct health effects. No direct comparison with external occupational risk indices is currently possible, but internal testing of the model reveals no obvious inconsistencies.     

Monte Carlo Simulation of Rodent Carcinogenicity Bioassays

In this paper we describe a simulation, by Monte Carlo methods, of the results of rodent carcinogenicity bioassays. Our aim is to study how the observed correlation between carcinogenic potency (beta or 1n2/TD50) and maximum tolerated dose (MTD) arises, and whether the existence of this correlation leads to an artificial correlation between carcinogenic potencies in rats and mice. The validity of the bioassay results depends upon, among other things, certain biases in the experimental design of the bioassays. These include selection of chemicals for bioassay and details of the experimental protocol, including dose levels. We use as variables in our simulation the following factors: (1) dose group size, (2) number of dose groups, (3) tumor rate in the control (zero-dose) group, (4) distribution of the MTD values of the group of chemicals as specified by the mean and standard deviation, (5) the degree of correlation between beta and the MTD, as given by the standard deviation of the random error term in the linear regression of log beta on log (1/MTD), and (6) an upper limit on the number of animals with tumors. Monte Carlo simulation can show whether the information present in the existing rodent bioassay database is sufficient to reject the validity of the proposed interspecies correlations at a given level of stringency. We hope that such analysis will be useful for future bioassay design, and more importantly, for discussion of the whole NCI/NTP program.     

VCCEP Pilot: Progress on Evaluating Children''s Risks and Data Needs

The Voluntary Children's Chemical Evaluation Program (VCCEP) is designed to provide information to the public on children's potential health risks associated with chemical exposures. The key question of the VCCEP is whether the potential hazards, exposures, and risks to children have been adequately characterized, and, if not, what additional data are necessary. To answer this question, manufacturers or importers of 23 chemicals were asked by the U. S. Environmental Protection Agency (U.S. EPA) to sponsor their chemicals in the first tier of a pilot program. These chemicals were selected for evaluation because they have been found as contaminants in human tissue or fluids (adipose tissue, blood, breath, breast milk, or urine); food and water children may eat and drink; or air children may breathe (including residential or school air). Under the VCCEP framework, sponsoring companies agree to prepare Tier 1 hazard, exposure, and risk assessments on the individual chemicals, and identify the need for additional data. These assessment documents are submitted to the U.S. EPA and subsequently undergo review by experts in an independent peer consultation meeting that is open to the public. Following this peer consultation process, the U.S. EPA reviews each submission and makes a data-needs determination, which may include requesting further data collection or generation by the sponsor. Sponsoring companies then decide whether to volunteer for the next tier and collect or generate the requested data. The purpose of this article is to describe the VCCEP process and to review and present the key findings from the first set of chemicals that have been fully or partially evaluated under the pilot program (vinylidene chloride, decabromodiphenyl ether, pentabromodiphenyl ether, octabromodiphenyl ether, acetone, methyl ethyl ketone, decane, undecane, and dodecane). Specifically, we provide a brief summary of the sponsors' submissions, the peer consultation panels' discussions, and the U.S. EPA's data-needs decisions. Although we do not attempt to conduct independent analyses of the underlying data, we do identify a number of common themes that have emerged during implementation of the pilot program and discuss several key issues that could become important in the future. The information presented here should be useful for various parties interested in the progress of the VCCEP and the results of the initial (Tier 1) children's assessments.