Disinfection byproducts and halogen-specific total organic halogen speciation in chlorinated source waters – The impact of iopamidol and bromide

This study investigated the speciation of halogen-specific total organic halogen and disinfection byproducts(DBPs) upon chlorination of natural organic matter(NOM) in the presence of iopamidol and bromide(Br~-).Experiments were conducted with low bromide source waters with different NOM characteristics from Northeast Ohio,USA and varied spiked levels of bromide(2-30 μmol/L) and iopamidol(1-5 μmol/L).Iopamidol was found to be a direct precursor to trihalomethane(THM) and haloacetic acid formation,and in the presence of Br~-favored brominated analogs.The concentration and speciation of DBPs formed were impacted by iopamidol and bromide concentrations,as well as the presence of NOM.As iopamidol increased the concentration of iodinated DBPs(iodo-DBPs) and THMs increased.However,as Br~-concentrations increased,the concentrations of nonbrominated iodo-and chloro-DBPs decreased while brominated-DBPs increased.Regardless of the concentration of either iopamidol or bromide,bromochloroiodomethane(CHBrClI) was the most predominant iodo-DBP formed except at the lowest bromide concentration studied.At relevant concentrations of iopamidol(1 μmol/L) and bromide(2 μmol/L),significant quantities of highly toxic iodinated and brominated DBPs were formed.However,the rapid oxidation and incorporation of bromide appear to inhibit iodoDBP formation under conditions relevant to drinking water treatment.     

Study on the simultaneous reduction of methylmercury by SnCl2 when analyzing inorganic Hg in aqueous samples

Mercury (Hg) is among the most concerned contaminants in the world. It has three major chemical forms in the environment, including Hg⁰, Hg^2 +, and methylmercury (MeHg). Due to their differences in toxicity, mobility, and bioavailability, speciation analysis is critical for understanding Hg cycling and fate in the environment. SnCl₂ reduction-atomic fluorescence spectrometry detection is the most commonly used method for analyzing inorganic Hg. However, it should be noted that MeHg may also be reduced by SnCl₂, which would result in the overestimation of inorganic Hg. In this study, the reduction of MeHg by SnCl₂ in both de-ionized (DI) water and four natural waters was investigated. The results showed that MeHg could be reduced by SnCl₂ in DI water whereas this reaction was hard to occur in tested natural waters. By investigating the effects of water chemical characteristics (dissolved organic matter, pH and common anions and cations) on this reaction, SO₄^2 ? was identified to be the dominant factor prohibiting SnCl₂ induced MeHg reduction in natural waters. SO₄^2 ? in natural waters was evidenced to be reduced to S^2 ? by SnCl₂ and the generated S^2 ? can complex with MeHg to form MeHgS^? which is hard to be reduced by SnCl₂. Findings of this study indicate that the effect of MeHg reduction by SnCl₂ on inorganic Hg analysis is negligible in natural waters; however, at simulated experimental systems without SO₄^2 ?, SO₄^2 ? should be added as protecting agents to prevent MeHg reduction when analyzing inorganic Hg if it would not cause any other unwanted effects.     

Carbon and hydrogen isotope effects during sorption of organic contaminants on carbonaceous materials

Stable carbon and hydrogen isotopes can be an efficient means to validate biodegradation of organic contaminants in groundwater since it results in an isotopic fractionation. A prerequisite in applying this method in the field is the proof that other processes decreasing the contaminant concentration are conservative with respect to isotope effects. In this paper we show for carbon isotopes of halogenated hydrocarbon compounds [trichloroethene (TCE), cis-dichloroethene (c-DCE), vinylchloride (VC)] and carbon and hydrogen isotopes of BTEX compounds (benzene, toluene, p-xylene) that no significant fractionation occurs during equilibrium sorption onto activated carbon, lignite coke and lignite. In general, effects were in the range of the reproducibility limit of the analytical instrument (0.5 per thousand for delta13C, and 8 per thousand for delta2H). This observation was made for fractions sorbed of less than 5% to more than 95%. Also for rate-limited sorption of TCE onto activated carbon, no significant fractionation in carbon isotopes could be observed. These findings support the assumption that for these classes of compounds, sorption processes in aquifer systems are conservative with respect to isotope effects.     

石门台自然保护区可持续发展对策

石门台自然保护区具有调节气候、涵养水源、调节径流、保持水土、降低河流含沙量、净化大气和水质、保护野生生物物种等多种生态功能,但其生态系统也具有脆弱性.为了促进自然环境的良性循环,促进水资源的可持续利用和经济的可持续发展,提出以下建议:加强宣传教育,加强保护措施,改善管理技术水平,建立可持续发展的经济体系.     

A new approach to sustainable tourism development: Moving beyond environmental protection

Tourism is one of the largest and fastest growing industries in the world. It is an increasingly important source of income, employment and wealth in many countries. Its rapid expansion has, however, had detrimental environmental (and socio-cultural) impacts in many regions. In this article, I examine the main economic benefits and environmental impacts of tourism, and review the development of the international sustainable tourism agenda. While much of international tourism activity takes place within the developed world, this article will focus on the (economic) development of the industry in developing countries I conclude that new approaches to sustainable tourism development in these countries should not only seek to minimize local environmental impact, but also give greater priority to community participation and poverty alleviation. I argue, in particular, that more emphasis should be given to a 'pro-poor tourism' approach at both national and international levels.     

Measuring good governance: piloting an instrument for evaluating good governance principles

ABSTRACT

As federal, state, and local governments and agencies respond to calls to make decisions and implement programs according to tenets of ‘good governance’, a need exists to develop methods for systematically evaluating performance. ‘Good governance’ has been characterized as including a wide array of principles, which vary across literatures. Comparatively little scholarship has sought to systematically quantify program achievement in accordance with these principles. We develop and present a scale for measuring program achievement in accordance with eight main principles of good governance: inclusivity, fairness, transparency, accountability, legitimacy, direction, performance, and capability. We present the results of a pilot implementation of the scale within the context of two community-based deer management programs. Our results suggest that these principles of good governance may not sort into distinct dimensions in a real-world context.     

高速铁路事故预防措施的研究

结合我国高速铁路广深线 (广州—深圳 )及秦沈线 (秦皇岛—沈阳 )的工程设计过程 ,分析了可能引发铁路事故发生的几方面的主要原因 :速度控制问题、轨道故障、自然灾害等 ,并对这些事故因素提出了预防措施。这些措施的实施对减少铁路事故的发生有着重要作用     

福建省台风灾害及减灾对策研究

根据《台风年鉴》和《福建省气候影响评价》,以及福建省防汛办的台风灾情记录及其它台风资料,分析了福建省台风灾害具有：颇次高,强度大,灾害时间集中,频度大,影响范围广,登陆地点集中;灾情严重和连锁反应显著等特点．并讨论了台风灾害对福建省经济发展的影响．最后针对福建省台风灾害特点提出减轻台风灾害的对策．     

Long-Term Growth Enhancement of Baldcypress (Taxodium distichum) from Municipal Wastewater Application

Taxodium distichum (L.) Rich.]. The study site, a swamp in St. Martin Parish, Louisiana, has received municipal wastewater for the last 40 years. Growth chronologies from 1920 to 1992 were developed from cross-dated tree core samples taken from treated and control sites with similar size and age classes. Mean diameter increment (DINC) and mean basal area increment (BAI) chronologies were constructed separately for each stand. These chronologies were then summarized by tree and stand into seven nine-year intervals resulting in three pretreatment intervals from 1926 to 1952 and four treatment intervals from 1953 to 1988. Significant differences in growth response between sites showed a consistent pattern of growth enhancement in the treated site coincident with the onset of effluent discharge. The ratio of treated to control baldcypress growth rates (computed from DINC) averaged 0.74 during the pretreatment period and 1.53 during the treatment period. Over the period of study, control DINC decreased from 77 mm to 29 mm/nine-year interval, while treatment DINC increased slightly from 40 mm to 47 mm/nine-year interval. Control BAI did not increase significantly and averaged 192 cm²/nine-year interval. There was a significant increase in treatment BAI from 129 to 333 cm²/nine-year interval over the period of record. These results clearly demonstrate sustained long-term baldcypress growth enhancement throughout 40 years of municipal effluent discharge.     

Butterflies (Lepidoptera: Papilionoidea and Hesperioidea) of Roxborough State Park, Colorado, USA: Baseline Inventory, Community Attributes, and Monitoring Plan

/ Roxborough State Park in Colorado's Front Range was established in 1975 following a history of cattle and sheep ranching by private ownership. Survey work conducted from 1979 to 1995 resulted in the documentation of 93 species of butterflies. A variety of factors are responsible for the composition of the butterfly community: (1) overgrazing and its effect on the presence or absence of specific butterfly host plants; (2) habitat differences resulting from topographical and geological features; and (3) ecological and historical biogeography. This study provides data on community sampling adequacy, along with estimates of effort needed to monitor trends in abundance by using a community self-similarity curve and power analysis. An annual monitoring plan is proposed to assess trends in community composition. The plan includes collection of presence/absence and abundance data for select butterflies based on natural history information.KEY WORDS: Butterfly communities; Grazing; Inventory; Monitoring; Natural history