China-Indian Silk Trade： Current Production and Future Prospects

As an important traditional labor-intensive industry of both India and China, the cocoon silk industry has long made great contributions to the ecological environment protection, rural economic development and the increase in export income of both countries. India is not only a very important cocoon silk trading partner, but an important production competitor of China. In recent years, there has been a large increase in the production and trade of the cocoon silk between China and India; however, China relies heavily on Indian market, which leads to a tendency of further deterioration in the silk trade environment between both countries. The present article makes an empirical study of the cocoon silk resources of the two countries and the scale, product mix and market structure of China-Indian silk trade from 2001 to 2007. Overall silk trading volumes from China to India and market concentration rate are on the increase because of the superiority of Chinese cocoon silk production over that of India. Owing to scattered market share and export that mainly focused on raw materials product, there has been a phenomenon of price reduction and quantity increase. India carries out fierce competition with China in the international market and even imposes antidumping sanction on Chinese silk, which are key factors restricting further increase between China-India trade. Based on the abovementioned facts, the authors aim to put forward suggestions for steadily developing the production and trade of China＇s silk.     

Agricultural Structure in Western China by Comparing with before and after CFFG Based on Shift-share Method

Based on shift-share method, this article employs re- gional share, structural shift and competitive shift to analyze the structural benefit and competitive position of agricultural structure in western China by comparing with agriculture, foresting, stockbreeding and fishing before and after Conversion of Farmland to Forest and Grassland （CFFG）. Then authors draw following conclusion： while CFFG program has been put in practice, the agricultural structure in western China has some typical characteristics, such as growth faster, structural predominance obvious and more competitive. But the contributiveness from the competition is not too much yet, and the structural benefit of forest estate and stockbreeding are restrained.     

Influence of titanium dioxide nanoparticles on speciation and bioavailability of arsenite

In this study, the influence of the co-existence of TiO₂ nanoparticles on the speciation of arsenite [As(III)] was studied by observing its adsorption and valence changing. Moreover, the influence of TiO₂ nanoparticles on the bioavailability of As(III) was examined by bioaccumulation test using carp (Cyprinus carpio). The results showed that TiO₂ nanoparticles have a significant adsorption capacity for As (III). Equilibrium was established within 30 min, with about 30% of the initial As (III) being adsorbed onto TiO₂ nanoparticles. Most of aqueous As (III) was oxidized to As(V) in the presence of TiO₂ nanoparticles under sunlight. The carp accumulated considerably more As in the presence of TiO₂ nanoparticles than in the absence of TiO₂ nanoparticles, and after 25-day exposure, As concentration in carp increased by 44%. Accumulation of As in viscera, gills and muscle of the carp was significantly enhanced by the presence of TiO₂ nanoparticles.     

河北省海岸带土壤盐渍化研究

在当今土地资源日益短缺的年代,作为一种土地资源,盐渍化土地越来越重要,越来越受到社会的普遍关注。本文通过分层采集土样,对整个河北省海岸带的土壤盐渍化进行了研究,在借鉴国内外先进经验的基础上,提出了土壤盐渍化防治和综合利用应视各国、各地具体情况而定,并指出盐渍土未来的研究趋势应以利用新技术、探寻新的改良方法及与农业生态和环境保护研究密切线合这三个方面为主。     

紫外线消毒技术用于污水处理的现状与发展前景

污水处理中紫外消毒方法与传统消毒方法相比之下具有不需要投加化学药剂、不产生有毒有害副产物、消毒效率高、操作简单、便于运行管理等特点。本文着重介绍了目前用于消毒的紫外灯的种类,并阐述了浊度、微生物种类、光复活性能等影响紫外消毒效果的因素,最后对未来紫外消毒方法发展的前景做出了分析。     

改性高岭土处理含酸性媒介染料的印染废水

用十六烷基三甲基溴化铵(CTMAB)改性的高岭土处理以水溶性酸性媒介染料为主的印染废水.实验结果表明,当CTMAB-高岭土加入量为0.6 g/L、用石灰乳控制废水pH为9.5～10.0、聚丙烯酰胺的加入量为2.0 mg/L时,废水的处理效果最佳,废水色度和COD去除率分别达到98.0%和92.0%以上,出水色度和COD达到了GB4287-92<纺织染整工业水污染物排放标准>一级排放标准.     

Atrazine contamination in agricultural soils from the Yangtze River Delta of China and associated health risks

Atrazine is one of the most widely applied and persistent herbicides in the world. In view of limited information on the regional contamination of atrazine in soils in China, this study investigated the spatial distribution and environmental impacts of atrazine in agricultural soils collected from the Yangtze River Delta (YRD) as an illustrative analysis of rapidly developing regions in the country. The results showed that the concentrations of atrazine in the YRD agricultural soils ranged from <1.0 to 113 ng/g dry weight, with a mean of 5.7 ng/g, and a detection rate of 57.7 % in soils. Pesticide factory might be a major source for the elevated levels of atrazine in Zhejiang Province. The contamination of atrazine was closely associated with land use types. The concentrations and detection rates of atrazine were higher in corn fields and mulberry fields than in rice paddy fields. There was no significant difference in compositions of soil microbial phospholipids fatty acids among the areas with different atrazine levels. Positive relationship (R = 0.417, p < 0.05, n = 30) was observed between atrazine and total microbial biomass. However, other factors, such as soil type and land management practice, might have stronger influences on soil microbial communities. Human health risks via exposure to atrazine in soils were estimated according to the methods recommended by the US EPA. Atrazine by itself in all the soil samples imposed very low carcinogenic risks (<10^?6) and minimal non-cancer risks (hazard index <1) to adults and children.     

肠道微生物对土壤中铜、锌、锰生物可给性的影响

为了更全面、准确地评价土壤中金属元素对人体的健康风险,研究土壤中金属元素在结肠阶段的生物可给性具有重要意义。通过采集我国一些地区的6种土壤,利用in vitro方法(PBET和SHIME联用)研究土壤中Cu、Zn、Mn在胃、小肠、结肠阶段的生物可给性。研究显示,土壤中Cu、Zn、Mn在胃阶段的生物可给性分别为23.8%~63.0%、21.2%~64.4%、11.7%~35.6%;从胃阶段到小肠阶段,土壤中Cu的生物可给性提高了0.4%~14.4%,而土壤中Zn在小肠阶段的生物可给性降低了6.7%~38.7%。结肠阶段,土壤中Cu、Zn、Mn的生物可给性分别为2.4%~12.9%、5.7%~18.7%、6.2%~18.9%,与小肠阶段相比,分别降低了21.7%~56.9%、0.4%~36.8%、4.5%~19.1%。结果表明,在肠道微生物存在的情况下,土壤中Cu、Zn、Mn在结肠阶段有较低的人体健康风险。     

中国典型河湖水体铅的水生生物安全基准与生态风险评价

采用物种敏感度排序法(SSR)对我国铅的淡水水生生物安全基准进行推导,并以太湖为例进行了流域水生生物安全基准推导。对于难以获得的本土生物毒性数据,开展了相应的毒性试验。获得了我国国家与太湖流域铅的水生生物安全基准值,基准最大浓度(CMC)分别为63.92、104.26μg·L-1,基准连续浓度(CCC)分别为1.21、4.06μg·L-1。同时,对我国主要河流以及太湖流域进行了铅的生态风险评价,联合概率曲线法显示影响5%水生生物种类的概率分别为66.22%和43.19%,熵值法则显示中国主要河流存在较大的铅暴露风险,因此,我国铅的潜在生态风险较大,主要河流与太湖流域存在铅污染问题。     

利用重组大肠杆菌SOS法评价污水厂出水的遗传毒性以及工艺去除效果

SOS/umu测试法被广泛应用于化合物和复杂混合物遗传毒性的评价,由于该技术所用菌种为致病菌且操作步骤繁琐等原因,制约了技术的推广应用。研究建立了基于重组大肠杆菌SOS效应的水质遗传毒性检测方法(专利号:ZL201110022476.1),应用该方法评价了某市4座污水厂出水的直接遗传毒性效应,同时以污水处理一厂为例考察了直接遗传毒性效应的季节变化规律以及不同的工艺对水中直接遗传毒性物质的去除情况。结果显示:各污水厂出水均表现出一定的直接遗传毒性,对应的4-NQO毒性当量浓度范围为0.018~0.514 mg·L-1;一年四季中夏季进出水直接遗传毒性效应最高,现有工艺中生化处理工艺段对直接遗传毒性去除效果最佳,去除率为33.33%。该方法操作便利、检测敏感性较高、操作危险性较低,可用于水中直接遗传毒性效应的测试。