软锰矿浆烟气同步脱硫脱硝资源化利用新工艺

燃煤烟气中的SO2和NOx是大气中重要的污染物,开发高效、经济的同步脱硫脱硝技术是环保领域的研究热点。针对现有同步脱硫脱硝技术存在的氧化剂成本较高和产物不能资源化利用等突出问题,提出了软锰矿浆烟气同步脱硫脱硝,并副产硫酸锰和硝酸锰的资源化新工艺。研究结果表明:软锰矿浆可以有效的脱除烟气中的SO2和NOx,反应产物分别为硫酸锰和硝酸锰。在烟道中注入臭氧,将难溶于水的NO快速氧化为NO2,可大大提高脱硝效率,在O3/NO=1.2的条件下可以达到72%的脱硝率、90%的脱硫率和85%的锰浸出率;吸收液经过空气氧化除铁和加入铜试剂除重金属后,结晶分离溶液得到的硫酸锰和硝酸锰可分别达到HG/T 2962—1999标准的硫酸锰产品和HG/T 3817—2006标准的工业硝酸锰产品要求。该工艺实现了SO2和NOx污染治理与低品位软锰矿资源化利用的双重目的,为SO2和NOx的资源化污染治理技术的开发和应用提供了新的思路。     

Arsenic in Two Taiwanese Bivalves,Crassostrea Gigas (Thumberg) and Meretrix Lusoria Röding

Abstract

Arsenic, one of the most toxic elements, is present naturally in marine organisms at much higher concentrations than in terrestrial organisms. the arsenic contents in two marine bivalves, Crassostrea gigas (Thumberg) and Meretrix lusoria Röding, from Taiwan were investigated. the total arsenic content of C. gigas (33.7–60.5 μg g^?1) is higher than that of M. lusoria (30.2–34.6 μg g^?1). These two bivalves from Lu-kang contain more arsenic in soft tissues than specimens from other areas (significant at 1%, t-test). On the other hand, samples from Pen-hu contain less arsenic than those from other areas (significant at 5%). the arsenic contents of other Indo-Pacific bivalves are also given for comparison.     

软骨藻酸神经毒性作用机制研究进展

在拟菱形藻引发的有毒赤潮中产生的记忆缺失性贝毒(amnesic shellfish poison,ASP)软骨藻酸,经贝类等海洋生物摄入进入食物链,在对海洋生物造成危害的同时,也对人类健康造成威胁。软骨藻酸中毒者临床上表现为呕吐、腹痛和头痛等症状,严重者出现神经系统功能紊乱,如昏迷、抽搐和记忆缺失。软骨藻酸结构上与兴奋性氨基酸谷氨酸相似,它可以通过直接活化KA(kainate)受体和AMPA(α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)受体介导兴奋性神经毒。本文主要从线粒体功能紊乱、内质网应激和神经炎症等方面就软骨藻酸的神经毒性作用机制进行了综述。     

A GIS-based moving window analysis of landscape pattern in the Beijing metropolitan area,China

Quantifying landscape pattern and its change is essential for monitoring and assessment of ecological consequences of urbanization. Using the GIS-based land-use data for 2002, we combined moving window analysis along an urban-rural gradient and around the urban centre with landscape metrics to quantify the spatial pattern of urbanization in Beijing. The results of moving window analysis along the urban-rural gradient indicated that, for class-level metrics, the spatial pattern of urbanization could be quantified using landscape metrics, different land-use types exhibited distinctive spatial signatures, and, for landscape-level metrics, the increase in urbanization in the metropolitan Beijing region has resulted in dramatic increases in patch density (PD), edge density (ED), and patch and landscape shape complexity, and sharp decreases in the largest and mean patch size (MPS), agriculture land-use type, and landscape connectivity. The results of moving window analysis around the urban centre showed that the direction of urbanization could be quantified using the class-level metrics, and landscape-level metrics indicated similar results to gradient analysis. In general, moving window analysis showed that the increasingly urbanized landscape became compositionally more diverse, geometrically more complex, and ecologically more fragmented.     

Water quality of Lugu Lake: Changes,causes and measurements

Lugu lake is an alpine lake in Yunnan Province in western China. It is famous for its beautiful scenery and the special culture of Mosuo people in this area. The lake is becoming contaminated and eutrophicated because of the huge number of visitors and improvements in agriculture during the last decade. This paper uses the water quality index (WQI) as an indicator to describe trends in contamination of Lugu Lake from 1995 to 2004 and analyses several parameters to determine the causes and consequences of contamination. We found that the dominant cause was pollution from tourism and suggest some feasible measures to prevent further deterioration of the lake water quality.     

Analysis of household energy consumption and related CO2 emissions in the disregarded villages of Lijiang City,China

Energy is one of the most important elements required for poverty alleviation and socioeconomic development, and it has a particularly strong impact on households in rural areas. An extensive survey on household energy consumption patterns that interrelates socioeconomic and demographic factors was conducted in the disregarded villages of Lijiang City by using the stratified random sampling technique for 120 households. This study focuses on household energy consumption and the related carbon dioxide (CO₂) emissions in the study area. Firewood, biogas, and electricity were identified as the main energy sources of the rural households. This study demonstrates that 100% of the households use firewood, 52% use biogas, and 95% use electricity as fuel types. On average, each household consumed 1752 kg of firewood, 280 m³ of biogas, and 392 kWh of electricity annually. All households generated an annual average amount of CO₂ emissions of 3851 kg, of which 85.08% come from firewood, 7.66% from biogas, and 7.26% from electricity. Family size, income, and educational level were found to be the major factors that influence CO₂ emissions. The results of this study may be useful in explaining the energy consumption characteristics in the rural areas of Lijiang City and are expected to be useful in policy formulation for energy consumption and environmental protection.     

食品烹调处理过程中砷的浓度、形态和生物可给性研究进展

食品作为人体砷暴露的主要途径,其砷的含量和形态备受关注。由于食品原料通常要经过烹饪加工后才会被人食用,因此,食品的烹调处理过程及方式对砷的形态及生物有效性的影响在砷的健康风险评价研究中,需要作为重要因素进行研究。通过综述不同食品烹调处理前后砷浓度、形态和生物可给性变化的相关研究,分析了砷变化的特征,探讨了相关机理,并得出如下结论:烹调处理能使食品中砷的浓度发生升高或降低;高温烹调能使食品中砷形态发生变化,目前研究结果确定的变化主要是砷甜菜碱的分解,烹调中食品砷形态变化的机理尚不明确。不同烹调方式下,食品中砷的生物可给性差异较大,砷的形态变化可能是其生物可给性差异的主要原因。烹调特别是高温烹调下食品砷浓度升高及形态变化导致的健康风险值得进一步关注。     

三峡小城镇污水处理厂污水处理工艺探讨

在调查研究三峡库区重庆段小城镇污水处理现状的基础上,根据库区水质特征、水环境保护的特殊要求和库区地理环境与经济条件特点,对适用污水处理工艺和技术进行比选,认为利用地形高差,采用跌水曝气式生物滤塔+氧化沟处理工艺适用于库区小城镇污水处理。     

基于层次分析法的危废渣库选址的环境经济适宜性分析

环境经济适宜性是以实现保护环境的同时通过选择场址降低渣库或填埋场投资、提高经济效益为目的。利用层次分析法对危废渣库选址的各限制因素逐层分析并构造判断矩阵,计算理论权重同时进行检验,结合各比选场址的实际情况确定实际权重,并对选址的环境经济适宜性进行综合评定,最终确定环境经济最适宜场址。该方法适用于多个渣库或填埋场场址的初步选址判断,将渣库或填埋场的环境经济适宜性选址由定性分析转为定量评定,增强了环境经济选址的科学性和合理性,为后续渣库或填埋场多个比选场址的初步选址提供参考。     

Cadmium distribution in rice plants grown in three different soils after application of pig manure with added cadmium

A glasshouse pot experiment was conducted to investigate Cd concentrations in the aboveground parts of two consecutive crops of rice and Cd availability in three different soils (loam, silt loam, and sandy loam) after application of pig manure with added Cd. Soil pH tended to increase with increasing application rate of pig manure from 1 to 3% (w/w, oven dry basis). Soil diethylene triamine pentaacetic acid (DTPA) extractable Cd showed a clear positive correlation with soil total Cd content and increased with increasing Cd amendment of the manure but showed no difference between the two manure application rates. Cd concentrations in the grain, husk, and straw were significantly and positively correlated with soil DTPA-extractable Cd (p < 0.001). Within each level of manure Cd, the higher rate (3%) of manure produced lower Cd concentrations in the grain, husk, and straw on all three soils than did the lower rate (1%) after the first crop, but this no longer occurred after the growth of the second crop. Grain Cd concentrations exceeded the Chinese National Food Quality Standard (0.2 mg kg(-1)) most often on the loam, with intermediate frequency on the silt loam, and least often on the sandy loam, the soil with the highest pH and lowest organic carbon content and cation exchange capacity.