西北地区水窖水质的污染原因及防治措施

文章结合我国西北地区雨水集蓄利用工程水质的基本情况,对典型地区水窖水质的检测数据、结果和污染成因作了分析,并提出了水窖防治水质污染的措施。     

大凌河朝阳段大型底栖无脊椎动物监测及BI指数评价

通过对大凌河朝阳段5个采样点9个样本的底栖动物监测分析,检出底栖动物59种,采用BI指数进行水质评价。调查结果表明,大凌河南大桥及上游河段为清洁,市区段下游为轻污染至中污染。     

新安江水库水环境主要问题及保护对策

新安江水库是钱塘江的重要水源,对保障钱塘江中下游的生态安全和水体功能起着举足轻重的作用。为阐明新安江水库在流域经济发展和人类活动的影响下水环境的主要问题及保护对策,促进饮用水安全保障及构建健康水域生态系统,本文对新安江水库历年的水环境指标、浮游生物群落结构及其变化及水域生态灾变事件资料进行了综合分析。目前新安江水库存在上游来水变差、局部水域藻类异常增殖、渔业生产不合理、营养程度加重等众多问题,但其突出问题是藻类生物量增长过快。新安江水库水环境保护工作要从关注水质向维持生态系统健康转变,并尽快开展生态保育工作,控制流域污染、降低藻类数量、减少藻类异常增殖影响、科学合理渔业生产是其下一步保护的关键。而关于新安江水库的研究,虽然有一定的研究基础和资料,但对水域生态系统缺乏系统认识。研究气候变化条件下新安江水库水域生态系统的结构和功能以及长期演变规律;水利调度导致水位调整对区域水动力学条件、营养物输送过程的影响及评价水利调度对水库重要环境因子和生态系统影响;渔业养殖对水环境的影响,特别是鲢、鳙鱼大水面积养殖对水库生态系统的影响应是今后新安江水库主要的研究领域和方向。     

基于组织因素的航空安全评价与分析

基于组织因素,从事故类型出发寻找影响航空安全的因素,并采用层次分析法进行评价,得出各个指标因素的权重,确定机组、天气、公司管理是事故链中居于前3位的因素.对机组提出采用"PACE进谏法"和建立人为失误数据库进行训练等建议;针对天气提出改进气象装备,尽早预测并采取措施等建议;对公司管理提出借鉴瑞典航空公司的事前评估、自愿报告免责制度以及安全旁听制度等建议.     

Experimental investigation of the e ect of flow turbulence and sediment transport patterns on the adsorption of cadmium ions onto sediment particles

The mechanism of flow turbulence,sediment supply conditions,and sediment transport patterns that affect the adsorption of cadmiumions onto sediment particles in natural waters are experimentally simulated and studied both in batch reactors and in a turbulencesimulation tank.By changing the agitation conditions,the sediment transport in batch reactors can be categorized into bottom sediment-dominated sediment and suspended sediment-dominated sediment.It is found that the adsorption rate of bottom sediment is much lessthan that of suspended sediment,but the sediment transport pattern does not affect the final(equilibrium)concentration of dissolvedcadmium.This result indicates that the parameters of an adsorption isotherm are the same regardless of the sediment transport pattern.Inthe turbulence simulation tank,the turbulence is generated by harmonic grid-stirred motions,and the turbulence intensity is quantifiedin terms of eddy diffusivity,which is equal to 9.84F(F is the harmonic vibration frequency)and is comparable to natural surfacewater conditions.When the turbulence intensity of flow is low and sediment particles stay as bottom sediment,the adsorption rateis significantly low,and the adsorption quantity compared with that of suspended sediment is negligible in the 6 h duration of theexperiment.This result greatly favors the simplification of the numerical modeling of heavy metal pollutant transformation in naturalrivers.When the turbulence intensity is high but bottom sediment persists,the rate and extent of descent of the dissolved cadmiumconcentration in the tank noticeably increase,and the time that is required to reach adsorption equilibrium also increases considerablydue to the continuous exchange that occurs between the suspended sediment and the bottom sediment.A comparison of the results ofthe experiments in the batch reactor and those in the turbulence simulation tank reveals that the adsorption ability of the sediment,andin particular the adsorption rate,is greatly over-estimated in the batch reactor.     

北京山区小流域治理措施综述

山区小流域综合治理,是中国治理水土流失的主要形式.近10年来,随着可持续发展概念的引入,山区小流域治理与经济开发、资源保护相结合的战略思想逐渐被人们认识和接受,实现流域的可持续发展,已成为当今小流域治理活动的准则.综述主要对北京山区小流域治理措施进行了总结,并指出小流域治理需要综合运用多种措施;小流域治理必须充分考虑流域特征,因地制宜,分类治理.     

Impact analysis of drought, water excess and salinity on grass production in The Netherlands using historical and future climate data

The coupled SWAP-WOFOST model was used to study the effects of increasing salinity of groundwater, drought and water excess on grass production in The Netherlands. WOFOST simulates crop growth and SWAP simulates transport of water, solutes and heat in the vadose zone. The model was tested using several datasets from field experiments. We applied the models at regional scale where we quantified the impact of various groundwater salinity levels on grass growth and production using historical weather data (1971-2000). The salt concentrations in the subsoil were derived from the National Hydrological Instrument. The results show that salinity effects on grass production are limited. In wet years the excess rainfall will infiltrate the soil and reduce salt water seepage. In a next step we used future weather data for the year 2050, derived from 3 Global Circulation Models. From each model we used data from two CO₂ emission scenarios. As expected higher temperatures increased drought stress, however, the production reduction as a result of salt water in the root zone is limited. Salt stress mainly occurred when irrigation was applied with saline water. The increased CO₂ concentration in combination with the limited drought stress resulted in increasing simulated actual and potential yields. Overall conclusion for grassland in The Netherlands: drought stress is stronger than stress caused by water excess which on its turn is stronger than salinity stress. Future water demand for irrigation may increase by 11-19% and result in water scarcity if water supply is insufficient.     

城镇污水处理排放标准改革的费效分析

从费用效果角度对提高城镇污水处理排放标准的科学性和可实施性进行探讨,利用污染源普查数据,通过城镇污水治理投资和运行函数的构建,计算不同处理规模和排放标准下的污水处理投资和运行费用,在全国层面上计算提高污水处理排放标准所需费用和污染物的减排效果.研究表明：污水处理厂的投资和运行费用的增加随着污水处理规模的增加而递减.以污...     

国外高绩效人力资源实践：理论回顾、分析与展望

顺应组织发展要求构建有效人力资源管理模式,增强企业的持续竞争力,已经成为战略人力资源管理的热点之一。通过梳理近年来相关研究成果,剖析国外高绩效人力资源实践的概念及其构成。从员工态度和行为、组织资本、组织能力等方面指出高绩效人力资源实践的结果变量。根据实证研究相关文献,梳理高绩效人力资源实践与企业绩效的内在关联性。在此基础上,提出高绩效人力资源实践的未来研究方向,为相关理论和实证研究提供指导。     

The water supply footprint (WSF): a strategic planning tool for sustainable regional and local water supplies

This paper introduces a new methodological approach of the ecological footprint explicitly addressing the sustainability of water supplies, which we call the water supply footprint (WSF). The WSF calculates the catchment area or water supply hinterland of a certain society and can serve as a strategic planning tool for local or regional water supplies linking the water demand with the water supply in a water supply footprint matrix. Based on regional water balances it estimates how much water can be appropriated for human use in an environmentally sustainable way.The proposed method is tested on the South East Queensland water supply in Australia, an area where water use restrictions are regularly imposed on the population. Applying the proposed method indicates that supply shortages may be avoided by considerably changing the organisation of water supply, thereby reducing and possibly even avoiding the necessity for large-scale supply side measures like additional sweet water reservoirs or desalination plants. In that way it is demonstrated that the WSF method is applicable at an early and strategic stage of water supply planning.