三唑醇杀菌剂对雄性丽斑麻蜥性腺系统的对映选择性影响

三唑醇(triadimenol,TN)是一种广泛使用的手性三唑类杀菌剂,它含有2个手性中心,4个手性对映体,其中,对映体A包括A1(R,S)和A2(S,R),对映体B包括B1(R,R)和B2(S,S)。三唑醇被认为是一种潜在的内分泌干扰物,能够影响生物体内雌雄激素的合成。为了研究三唑醇不同对映体和外消旋体对爬行动物性腺系统影响的差异,以雄性丽斑麻蜥为实验动物,将外消旋体和4种对映体(100 mg·kg~(-1)bw)分别经口暴露给雄性蜥蜴28 d。外消旋体和(R,S)对映体暴露后蜥蜴的性腺体细胞指数(GSI)明显低于对照组。(S,R)、(R,S)和(S,S)显著抑制了性腺中性激素合成相关基因(cyp119a、cyp11a、cyp17、hsd-3β、hsd-17β、erα和ar)的表达量,同时降低了血液中睾酮(T)和雌二醇(E2)含量。(R,R)暴露对丽斑麻蜥体内的雌雄激素水平无明显影响。此外,相关性分析表明,外消旋体对性腺中性激素合成相关基因的影响与(R,S)具有较强的相关关系,说明(R,S)可能是外消旋体中生物活性和毒性最高的单体。研究表明,三唑醇对丽斑麻蜥性腺系统的毒性作用具有明显的对映选择性,这为手性农药对爬行动物的生态毒理学评价提供了重要依据。     

Assessing pollution prevention program by QUAL2E simulation analysis for the Kao-Ping River Basin, Taiwan

Wise and sustainable uses of water resources are essential for an effective river-basin-management planning. Recent management strategy further addresses the fact that quantity and quality of water are closely interrelated, and both must be considered simultaneously for all water resources and water quality management practices. The aim of this paper is to explore the impacts of water resources redistribution and pollution prevention actions between and within river basins simultaneously in South Taiwan. Much emphasis will be placed on assessing the impacts of water transfer over natural boundary to satisfy the needs of industrial development in the Tseng-Wen River system and its resultant influence on the water quality in the downstream area of the Kao-Ping River system where the pollution prevention program is to be implemented. The Kao-Ping River was further characterized hydraulically and environmentally, based on a full investigation of discharges and withdrawals in the river reaches. QUAL2E was successfully calibrated and validated using data collected between 1998 and 1999, and the model was capable of predicting the concentrations of biochemical oxygen demand, dissolved oxygen, total phosphate-phosphorus, and ammonia-nitrogen (NH3-N) for the entire river system. With the aid of QUAL2E simulation model, it shows eliminating the pig farming activities and constructing the sewer systems in the upstream area of Kao-Ping River cannot guarantee the full compliance with water quality standards in the downstream area and water transfer in the upstream area further increases negative impacts on the water quality in the wet season. The predicted situation of water quality in the dry season may even present worse condition. Additional water pollution control policy, such as the use of economic instruments, for controlling and reducing the waste-load of biochemical oxygen demand and ammonia-nitrogen is needed in the Kao-Ping River system in the long run.     

Efficient regional ozone control strategies for the eastern United States

When environmental regulatory bodies formulate control plans, it is incumbent upon them to try to achieve the stated goals in an economically efficient manner. The US Environmental Protection Agency (EPA) is presently developing regulations to limit the influence of transported ozone on areas that are having difficulty meeting the ambient air quality standard. EPA has proposed stringent control measures for emissions of nitrogen oxides (NOx) in 22 states of the eastern US. The strategy would necessitate the use of selective catalytic reduction or similar high-performance technology on almost all major power plants in the region, as well as extensive controls on industrial sources. This paper suggests several alternative approaches that would achieve equal or better environmental improvement at lower cost. These include focusing control efforts on sources closer to the North-east Corridor, pushing controls on close-in sources to a higher level of technology performance, and relaxing the stringency of requirements for states remote from ozone problem areas. All the approaches examined are two to three times more cost-effective than EPA's proposed approach in the North-east Corridor.     

Assessing relocation strategies of urban air quality monitoring stations by GA-based compromise programming

This paper presents a GA-based compromise programming technique for assessing the relocation strategy of urban air quality monitoring network with respect to the multi-objective and multi-pollutant design criteria. While the impact of conservative, quasi-stable, and reactive pollutants are considered in the design principles via a simulation analysis, cost, effectiveness, and efficiency characteristics are postulated in the optimization process. Therefore, technical coverage for illustrating the needs of siting air quality monitoring stations (AQMS) includes both the air quality simulation and optimization modeling analyses in a two-stage analytical framework simultaneously. It starts from determining the spatial interrelationship among those candidate sites using various types of air quality simulation models as an integrated means. And the outputs drawn from the simulation models can then be used as the required inputs in the compromise programming model in order to screen all those siting alternatives that may satisfy the planning goals subject to the essential constraints throughout the multi-objective optimization process. For the illustrating purposes, a series of technical settings for finding the optimal relocation scenarios of AQMS were examined in the case study for the city of Kaohsiung in South Taiwan where the long-term violations of official standards of ozone and particulates turn out to be critical. It not only expresses the ideas of relocation strategy but also indicates how to utilize those alternatives in the decision-making process for improving the functionality of air quality monitoring in the urban environment. Experience gained in this study clearly indicates that the more the number of pollutants and objectives considered simultaneously, the higher the number of candidate sites to be selected in the relocation strategy.     

Effect of chloride ions on the oxidation of aniline by Fenton's reagent

The objective of this study was to experimentally probe the mechanism of chloride ions specifically affecting aniline oxidation by Fenton's reagent. Batch experiments were carried out to investigate the effects of pH, Fe2+, H2O2 and chloride concentration on the oxidation reaction. Results show that the inhibition caused by chloride ions can be overcome by extending the reaction time if the concentration of chloride ions is low. At a high concentration of chloride ions, however, the oxidation of aniline was inhibited, and actually ceased due to the complexation of Fe-Cl. In this study, the chloride ion concentration was kept at 0.2 M in the experiments when studying the effect of ferrous ion concentration on the Fenton reaction. If the ratio of [Cl-]/[Fe2+] was < or = 200, the inhibition effect was very significant. In other words, adding more ferrous ions rather than hydrogen peroxide can break the inhibition originating from the chloride ions at an initial stage of pH 3. The inhibition effect of chloride ions on the aniline reaction depended on the reaction pH; the extent of inhibition decreased with increasing the initial pH as long as the pH was less than 5. Consequently, the inhibition effect by chloride ions was primarily due to the complexation of iron species and chloride ions. The influence of chloride ions on aniline oxidation due to the competition of hydroxyl radicals was not significant.     

CHANGES IN WATER QUALITY IN THE NEWLY IMPOUNDED SUBTROPICAL FEITSUI RESERVOIR,TAIWAN1

ABSTRACT: Water quality and trophic conditions in the Feitsui Reservoir, a subtropical reservoir, were evaluated with data from a ten-year data base to depict the impacts of river impoundment upon the chemical and biological characteristics of a reservoir, and to discuss the effects of flushing rate on in-lake phosphorus concentrations and phytoplankton growth. The results of the investigation showed that during the incipient impounding period, the water quality in the Feitsui Reservoir was significantly affected by internal loadings from submerged vegetation and soil in the flooded area. Studies of the changes in phosphorus compounds indicated that total phosphorus concentration appeared to approach equilibrium after the seventh year of impoundment and that orthophosphate stabilized after the sixth year of impoundment. Concentrations of both phosphorus forms varied seasonally after attaining stability. Nitrogen compounds (NH₃-N, NO₃-N and NO₂-N) approached equilibrium within three years after impoundment. The seasonal variation in carbon was correlated to the number of phytoplankton. The mean value of the N:P mass ratio has remained over 110 since year seven of impoundment (1990), indicating that phosphorus constitutes the potential limiting nutrient in the growth of phytoplankton. The rapid flushing rate (132.11 and 110.43 yr^-1) in Feitsui Reservoir during the first and second impounding stages was a critical factor influencing the phytoplankton growth response to available nutrients.     

原油对草原植被的影响

为了定量说明落地原油对大庆地区草原植被的影响，选择了四种植物群落进行浇原油试验，浇油厚度为0．2、0．4、0．8cm，浇油时间为秋、春、夏。试验结果表明原油对植物个体的影响因原油量、季节和植物种类的不同而不同，随原油量的增加影响增大。     

A PROPOSED METHOD FOR DROUGHT MONITORING1

ABSTRACT: Existing definitions of drought have focused on limited hydrologic indicators and are less effective for the purpose of drought monitoring. This study uses historical records of streamflow, precipitation, ground water, temperature, and lake elevation to define drought. Based on the method of truncation, drought durations and conditional probabilities of each indicator were estimated to define the drought severity levels, namely, 70 percent, 80 percent, 90 percent, and 95 percent. A drought monitoring method was developed by a combination of truncation level, duration, and conditional probabilities of five indicators. A six-month period of the 1988 drought in the central Ohio region was used to test the monitoring method. It was found that the developed method could effectively detect an occurrence of drought.