北京和上海典型复合包装废物处置环境影响比较

采用生命周期评价法研究比较了北京和上海两地纸塑铝复合包装处置阶段的环境影响。通过现场和资料调研的方式获得此阶段的能量物质的输入输出和环境外排数据。结果表明:北京和上海两地纸塑铝复合包装处置阶段的环境影响潜值分别为-0.428 Pt和9.776 Pt,其主要集中在气候变化、土地占用和无机物对健康的损害三方面;每提高10%的回收率,其环境影响潜值北京和上海可分别降低5.446 Pt和5.799 Pt;上海地区纸塑铝复合包装处置阶段对环境的影响在任何同回收率的情况都要高于北京地区,其主要原因是上海地区填埋产生的温室气体释放量过大和再生企业距离打包点较远。     

脱硫灰与钾矿石复合生产钾钙硅镁硫肥料研究

对脱硫灰与钾矿石复合生产钾钙硅镁硫肥的研究意义、反应原理、生产流程、环境安全性能以及施肥方法等进行了介绍和评估,并对其应用前景进行了展望。研究结果表明:利用脱硫灰与钾矿石复合生产钾钙硅镁硫肥在理论上可行;生产出的产品中硫酸钾的含量达10.34%～12.0%,枸溶氧化钙19.06%～32.28%,枸溶二氧化硅10.98%～14.46%,枸溶氧化镁1.46%～1.82%。产品的pH值从原脱硫灰的10.65下降到9.60。重金属含量低于农用粉煤灰国家标准,生产过程中不会产生SO2等有害气体污染。肥料的生产成本低于350元/t,该肥料不但可以增加土壤中钾、钙、硅、镁和硫等中微量元素的含量,而且可以提高或改善农作物的产量和品质。达到变废为宝,促进循环经济发展之目的。     

贸易开放、劳动力转移和就业

长久以来主流国际贸易模型中充分就业的假设使经济学界忽略了对贸易开放如何影响就业的分析,而哈里斯-托达罗模型则为此提供了一个可供扩展的框架.将哈里斯-托达罗模型扩展到存在贸易开放的情况后,本文发现如果一国的比较优势为制造品,贸易开放将会减少就业,这是因为制造品价格的提高会吸引更多的劳动力从农业向制造业转移,而制造业部门劳动力市场刚性的存在则阻碍了劳动需求的增加.为了研究我国改革开放以来贸易开放对就业的影响机制,并且考虑到就业的持续性,本文利用我国省际面板动态数据进行实证研究,并使用国有企业和政府部门劳动力占比度量我国劳动力市场刚性程度.实证研究结果发现当不考虑劳动市场刚性时,由于我国的比较优势是劳动密集型产品,贸易开放能增加就业;而当劳动力市场刚性较大时,劳动力转移过程反而促使贸易开放减少我国的就业,恰好验证了本文的理论分析结果.该文的政策含义则意味着政府应努力降低劳动力市场刚性以促使贸易开放增加就业.     

国内外游客安全管理研究进展

安全是旅游业的生命线,是游客在旅游过程中首要关心的问题,对旅游目的地的可持续发展具有重要意义。为了探讨游客安全研究中存在的问题及发展方向,在参阅研究文献的基础上,从游客安全意识、成因、评估和保障等方面,对国内外游客安全研究进展进行了评述。     

Inferring chemical effects on carbon flows in aquatic food webs: Methodology and case study

The majority of ecotoxicological enclosure experiments monitor species abundances at different chemical concentrations. Here, we present a new modelling approach that estimates changes in food web flows from such data and show that population- and food web level effects are revealed that are not apparent from abundance data alone. For the case of cypermethrin in freshwater enclosures, photosynthesis and excretion (d⁻¹) of phytoplankton at 3.643 μg L⁻¹ cypermethrin were 30% lower and 100% higher than in the control, respectively. The ingestion rate of mesozooplankton (d⁻¹) was 6 times higher in the treated enclosures than in the control as food concentration increased with insecticide exposure. With increasing cypermethrin concentrations, nanoflagellates progressively relied on phytoplankton as their main food source, which rendered the food web less stable. We conclude that this tool has excellent potential to analyse the wealth of enclosure data as it only needs species abundance and general constraints.     

Ecological risk of anthropogenic pollutants to reptiles: Evaluating assumptions of sensitivity and exposure

A large data gap for reptile ecotoxicology still persists; therefore, ecological risk assessments of reptiles usually incorporate the use of surrogate species. This necessitates that (1) the surrogate is at least as sensitive as the target taxon and/or (2) exposures to the surrogate are greater than that of the target taxon. We evaluated these assumptions for the use of birds as surrogates for reptiles. Based on a survey of the literature, birds were more sensitive than reptiles in less than 1/4 of the chemicals investigated. Dietary and dermal exposure modeling indicated that exposure to reptiles was relatively high, particularly when the dermal route was considered. We conclude that caution is warranted in the use of avian receptors as surrogates for reptiles in ecological risk assessment and emphasize the need to better understand the magnitude and mechanism of contaminant exposure in reptiles to improve exposure and risk estimation.     

不同模糊评价方法在水环境质量评价中的应用比较

近年来,运用模糊评价方法对水质和水体营养化程度进行评价逐渐受到重视。目前,对模糊评价方法的研究多集中在实测数据标准化、权重的确定和模糊模式识别模型研究几个方面。以滇池历年营养物质数据为实测数据,通过对几种实测数据标准化方法、权重确定方法和模糊模式识别方法的组合应用,获得水环境质量模糊评价最优组合方法。结果表明,在评价方法中,实测数据标准化方法采用线性内插法,权重的确定采用超标倍数法,模糊模式识别模型采用广义海明距离和加权海明距离法,即采用超标倍数法的广义海明距离和加权海明距离法能够更真实反映水环境质量的实际情况。     

Enantioselectivity in environmental risk assessment of modern chiral pesticides

Chiral pesticides comprise a new and important class of environmental pollutants nowadays. With the development of industry, more and more chiral pesticides will be introduced into the market. But their enantioselective ecotoxicology is not clear. Currently used synthetic pyrethroids, organophosphates, acylanilides, phenoxypropanoic acids and imidazolinones often behave enantioselectively in agriculture use and they always pose unpredictable enantioselective ecological risks on non-target organisms or human. It is necessary to explore the enantioselective toxicology and ecological fate of these chiral pesticides in environmental risk assessment. The enantioselective toxicology and the fate of these currently widely used pesticides have been discussed in this review article.     

Predicting molybdenum toxicity to higher plants: Estimation of toxicity threshold values

Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED₅₀) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered.     

河北省祖山风景区崩塌灾害特征与防治对策研究

以祖山为例,阐述了崩塌地质灾害的机理、特征和现状,并利用传递系数法对崩塌稳定性进行了计算和评价,采用削方卸载、修建抗崩塌挡土墙、构筑排水沟与格构等工程设施的防治对策及工程措施,取得了预期的效果。