Low bone density and renal dysfunction following environmental cadmium exposure in China

This paper presents the main findings of a study on health effects of environmental cadmium pollution in China, performed in 1998, i.e. approximately 25 years after the first warnings of such effects were published in Ambio. Forearm bone mineral density (BMD) and renal dysfunction were assessed in population groups exposed to cadmium via rice. Decreased BMD was found in postmenopausal women with elevated urinary cadmium (CdU) or cadmium in blood (CdB) and among men with elevated CdB. Also, clear and statistically significant dose-effect and dose-response relationships were found between CdB or CdU and renal dysfunction (increased excretion of retinol-binding protein). This is the first report of bone effects among Cd-exposed population groups in Asia outside Japan. The report is also of interest since it demonstrates that bone effects, a comparatively severe adverse health effect of Cd, in combination with renal dysfunction, still occurs in environmentally exposed population groups in Asia. Recent reports on bone effects in Cd-exposed population groups in Europe are discussed.     

Subtropical urban turfs: Carbon and nitrogen pools and the role of enzyme activity

Urban grasslands not only provide a recreational venue for urban residents, but also sequester organic carbon in vegetation and soils through photosynthesis, and release carbon dioxide through respiration, which largely contribute to carbon storage and fluxes at regional and global scales. We investigated organic carbon and nitrogen pools in subtropical turfs and found that dissolved organic carbon(DOC) and dissolved organic nitrogen(DON)were regulated by several factors including microbial activity which is indicated by soil enzymatic activity. We observed a vertical variation and different temporal patterns in both soil DOC, DON and enzyme activities, which decreased significantly with increasing soil depths. We further found that concentration of soil DON was linked with turf age. There were correlations between grass biomass and soil properties, and soil enzyme activities. In particular, soil bulk density was significantly correlated with soil moisture and soil organic carbon(SOC). In addition, DOC correlated significantly with DON. Significant negative correlations were also observed between soil total dissolved nitrogen(TDN) and grass biomass of Axonopus compressus and Zoysia matrella. Specifically, grass biomass was significantly correlated with the soil activity of urease and β-glucosidase. Soil NO3-N concentration also showed negative correlations with the activity of both β-glucosidase and protease but there were no significant correlations between cellulase and soil properties or grass biomass. Our study demonstrated a relationship between soil C and N dynamics and soil enzymes that could be modulated to enhance SOC pools through management and maintenance practices.     

邻硝基苯基荧光酮与铝显色反应的研究及其应用

研究了在溴化十六烷基吡啶存在下，邻硝基苯基荧光酮与铝显色反应的条件，结果表明，在ｐＨ５．０的乙酸－乙酸钠缓冲溶液中，Ａ１（Ⅲ）与邻硝基苯基荧光酮生成一种玫瑰红色给合物，其最大吸收波长在５５９ｎｍ，摩尔吸光系数为７．８２×１０４，比耳定律范围０～１０μｇ／２５ｍｌ，拟定了测定饮茶、饮水中微量铝的方法，结果令人满意。     

实用型深度光氧化设备对几种染料和多菌灵农药废水的处理

利用HFS 1型深度光氧化废水处理设备对活性艳蓝K3R、酸性红 3B、活性黑KNB、酸性红A、直接耐酸大红4BS等 5种染料的水溶液和多菌灵农药废水进行了深度光氧化处理。结果表明 :(1)染料在处理 5min后 ,脱色率都在 90 %以上 ;处理 15min后 ,CODCr的去除率除活性艳蓝K3R较低外 ,其余的都在 80 %以上 ;BOD5/CODCr的值都有所增大。 (2 )多菌灵农药废水 (经稀释 )处理 4 0min后CODCr的去除率为 5 7.0 % ,BOD5/CODCr的值由 0 .2 0增加到 0 .4 4。 (3)采用深度光氧化 -絮凝的工艺处理多菌灵农药废水 ,CODCr的去除率为 5 7.5 %。     

中国古代生态安全与可持续发展

中国自然生态优越但脆弱。农业历史悠久,但盲目扩大农耕造成生态破坏,威胁生态安全与可持续发展。由于中国古代农牧业分区发展,农耕灌溉施肥,精耕细作,保护了土地资源。农业中心由黄河流域逐步迁移到长江流域,维持了可持续发展,但经验教训十分深刻。     

中荷水处理示范研究培训中心的工作领域与思路

中荷水处理示范研究培训中心是中荷合作的产物,今后将对中国各城市污水处理技术人员、高校师生等进行培训,为建设和管理污水处理厂提供技术咨询,开展污水处理新技术的开发与推广,并开展对内对外的合作与交流。     

高岭土制备聚合氯化铝新工艺

介绍了以高岭土为原料，经盐酸预处理后，加水聚合、调整反应液pH，制备液体聚合氯化铝净水剂的新工艺。对所得产品的净水性能和技术指标进行了测定，结果表明，采用该工艺制得的聚合氯化铝产品技术指标符合GB1592－95标准。     

基于顶板离层监测的锚固巷道稳定性控制

在提出顶板离层概念的基础上 ,对顶板离层与锚固系统的变形协调条件以及离层临界值、失稳临界值及工程估计值的确定进行了分析 ;通过实例 ,说明了离层监测与反馈的应用 ;工程实践表明 ,采用顶板离层监测是锚固巷道稳定性控制的简易技术手段 ,其技术经济效果明显 ,是一种值得推广的实用方法     

自行车变速轴零件的冷挤压

自行车变速轴零件的冷挤压是我国早期应用无屑加工技术制造高难度复杂零件的典型范例之一,此文作者针对4种内齿、内棘齿零件冷挤压成形的研制过程,着重介绍了其中一种零件的挤压工艺分析、实际生产工序和所用模具的特点,对长期处于保密状态的技术予以适当解密。     

Are chaos and catastrophe theories relevant to environmental sciences?

Data acquired in the area of Environmental Sciences are by their very nature often discontinuous and abrupt. As such, the mathematical theories of catastrophe and chaos may be of use in analyzing such scientific data and in formulating mathematical models.