南苕溪支流锦溪水质时空变化特征分析

综合运用灰色聚类法、综合污染指数法、等级聚类法就南苕溪支流锦溪近年水质时空变化特征进行分析。结果表明,锦溪入青山水库断面水质2005—2009年逐年改善,2007年后达到灰色聚类等级Ⅲ类水质要求;2009年秋季至2010年夏季期间秋、冬两季的污染程度高于春、夏季节;枯水期综合污染指数最高,但TN、TP污染分指数在丰水期最高,表明污染源中面源污染已占相当比例。空间变化方面从玲珑桥到江桥锦溪水质的综合污染指数不断提升,到江桥时达到极值13.25,锦溪末端三眼桥断面水质较江桥断面有所改善;SPSS空间聚类分析可分为轻污染区(从玲珑桥到冬韵桥)、重污染区(从群利桥到江桥)和中度污染区(从江桥到三眼桥)。锦溪上游农业区对河水中的COD、TN和TP的贡献率分别为66%、54%和49%,农业面源污染已成为制约锦溪水质改善的主要因素。     

利用多年期赤泥和煤矸石制备烧结砖

以多年期赤泥和煤矸石为主要原料,分析了其化学成分和物性特征,通过设计不同的原料配比和烧结温度,探讨其最佳工艺条件以及各种参数指标,试图为赤泥的大宗化利用提供一种新的途径。实验结果表明最佳工艺条件为:多年期赤泥与煤矸石质量比为20∶80,成型压力为6 MPa,烧结温度为1 100℃左右保温2 h。烧结砖体"泛霜"现象基本消失,抗压强度为12.18 MPa、吸水率为21.6%,满足国家粉煤灰普通烧结砖GB5101-2003中的要求。     

沙雷氏菌发酵蓝藻生产蛋白酶

以富含蛋白质的蓝藻作有机氮源进行微生物发酵生产蛋白酶,为蓝藻的资源化利用提供一条新途径。采用单因素实验,研究了影响沙雷氏菌发酵蓝藻生产蛋白酶的培养基主要成分。结果发现,在实验范围内,沙雷氏菌发酵蓝藻生产蛋白酶的最佳碳源是蔗糖,最佳速效氮源是尿素,最佳金属离子(盐)是ZnSO4,最佳产酶促进剂是吐温80。在单因素实验中,发酵上清液的蛋白酶活最高可达到941 U/mL,而且发酵周期短,发酵培养18 h即可达到最高酶(活)值。     

Characterization of mercury species in brown and white rice (Oryza sativa L.) grown in water-saving paddies

In China, total Hg (Hg_T) and methylmercury (MeHg) were quantified in rice grain grown in three sites using water-saving rice cultivation methods, and in one Hg-contaminated site, where rice was grown under flooded conditions. Polished white rice concentrations of Hg_T (water-saving: 3.3 ± 1.6 ng/g; flooded: 110 ± 9.2 ng/g) and MeHg (water-saving 1.3 ± 0.56 ng/g; flooded: 12 ± 2.4 ng/g) were positively correlated with root-soil Hg_T and MeHg contents (Hg_T: r² = 0.97, MeHg: r² = 0.87, p < 0.05 for both), which suggested a portion of Hg species in rice grain was derived from the soil, and translocation of Hg species from soil to rice grain was independent of irrigation practices and Hg levels, although other factors may be important. Concentrations of Hg_T and other trace elements were significantly higher in unmilled brown rice (p < 0.05), while MeHg content was similar (p > 0.20), indicating MeHg infiltrated the endosperm (i.e., white rice) more efficiently than inorganic Hg(II).     

不同温度对SBR腐殖活性污泥系统运行效能的影响

在10～22℃范围内,通过实验考察了温度对腐殖土间歇式活性污泥处理(SBR)系统的运行特性的影响.实验结果表明,降低温度对SBR腐殖活性污泥系统去除COD影响不大,当温度降至10℃时,COD去除率仍可达到80%以上;在22～14℃范围内,SBR腐殖活性污泥系统对NH+4-N和TN的去除影响不大,温度降至10℃时,NH+...     

氧化节杆菌对铜溶液的吸附特性

以氧化节杆菌为吸附剂,处理Cu（NO3）2、CuSO4和CuCl2溶液,研究菌体对Cu2＋和NO3-的吸附效果,以及NO 3-、SO42-和Cl-对Cu2＋吸附的影响。结果表明氧化节杆菌对Cu2＋和NO 3-的吸附具有选择性。Cu2＋的吸附效果理想,0.1 g/L菌体在10 min时,对2 mg/L Cu2＋的吸附率达...     

Photocatalytic inactivation of Escherichia coli by natural sphalerite suspension: effect of spectrum, wavelength and intensity of visible light

The photocatalytic disinfection of Escherichia coli K-12 is investigated by the natural sphalerite (NS) under different spectra, wavelengths and intensities of visible light (VL) emitted by light-emitting-diode lamp (LED). The spectrum effect of VL on disinfection efficiency is studied by using white LED, fluorescent tube (FT) and xenon lamp (XE), which indicates that the “discreted peak spectrum” of FT is more effective to inactivate bacteria than “continuous spectrum” of LED and XE. Besides, the photocatalytic disinfection of bacteria is compared under different single spectrum (blue, green, yellow and red color) LEDs. The results show that the most effective wavelength ranges of VL for photocatalytic disinfection with the NS are 440-490 and 570-620 nm. Furthermore, a positive relationship is obtained between the disinfection efficiency and the VL intensity. The experiment shows that NS can completely inactivate 10⁷ cfu mL⁻¹E. coli K-12 within 8 h irradiation by white LED with the intensity of 200 mW cm⁻² at pH 8. Moreover, the destruction process of the cell wall and the cell membrane are directly observed by TEM. Finally, no bacterial colony can be detected within a 96 h regrowth test of inactivated bacteria, which reveals that the VL-photocatalytic disinfection leads to an irreversible damage to the bacterial cells.     

Development of a novel mathematical model using a group contribution method for prediction of ionic liquid toxicities

A new mathematical model has been developed that expresses the toxicities (EC₅₀ values) of a wide variety of ionic liquids (ILs) towards the freshwater flea Daphnia magna by means of a quantitative structure-activity relationship (QSAR). The data were analyzed using summed contributions from the cations, their alkyl substituents and anions. The model employed multiple linear regression analysis with polynomial model using the MATLAB software. The model predicted IL toxicities with R² = 0.974 and standard error of estimate of 0.028. This model affords a practical, cost-effective and convenient alternative to experimental ecotoxicological assessment of many ILs.     

China’s Primary Programs of Terrestrial Ecosystem Restoration: Initiation, Implementation, and Challenges

China has undertaken several major programs of terrestrial ecosystem restoration (ERPs) in recent years, including the Natural Forest Protection Program (NFPP) and the Sloping Land Conversion Program (SLCP). There have been reports on the implementation of these programs, their preliminary impacts, and the problems encountered in carrying them out; a great deal has been learned from these studies. Nonetheless, China’s ERPs are not limited to the NFPP and the SLCP. Because a complete documentation and a timely update of these major efforts are still missing from the literature, it is difficult to gauge the scope of these programs and the scale of their impacts. In addition, a more thorough and critical analysis of both the general ERP policy and the specific technical measures used in implementing the ERPs remains urgently needed. The purpose of this article is to tackle these tasks. Overall, with the huge government investments in the ERPs, tremendous progress has been made in implementing them. To complete them successfully and to fundamentally improve the targeted ecosystems, however, it is essential for China to have a more balanced and comprehensive approach to ecological restoration. This approach must include: adopting better planning and management practices; strengthening the governance of program implementation; emphasizing the active engagement of local people; establishing an independent, competent monitoring network; and conducting adequate assessments of program effectiveness and impact.     

Quantifying the Effect of Ecological Restoration on Soil Erosion in China’s Loess Plateau Region: An Application of the MMF Approach

Land degradation due to erosion is one of the most serious environmental problems in China. To reduce land degradation, the government has taken a number of conservation and restoration measures, including the Sloping Land Conversion Program (SLCP), which was launched in 1999. A logical question is whether these measures have reduced soil erosion at the regional level. The objective of this article is to answer this question by assessing soil erosion dynamics in the Zuli River basin in the Loess Plateau of China from 1999 to 2006. The MMF (Morgan, Morgan and Finney) model was used to simulate changes in runoff and soil erosion over the period of time during which ecological restoration projects were implemented. Some model variables were derived from remotely sensed images to provide improved land surface representation. With an overall accuracy rate of 0.67, our simulations show that increased ground vegetation cover, especially in forestlands and grasslands, has reduced soil erosion by 38.8% on average from 1999 to 2006. During the same time period, however, the change in rainfall pattern has caused a 13.1% ± 4.3% increase in soil erosion, resulting in a net 25.7% ± 8.5% reduction in soil erosion. This suggests that China’s various ecological restoration efforts have been effective in reducing soil loss.