Higher Cd adsorption on biogenic elemental selenium nanoparticles

Cadmium (Cd) is a carcinogenic metal contaminating the environment and ending up in wastewaters. There is therefore a need for improved methods to remove Cd by adsorption. Biogenic elemental selenium nanoparticles have been shown to adsorb Zn, Cu and Hg, but these nanoparticles have not been tested for Cd removal. Here we studied the time-dependency and adsorption isotherm of Cd onto biogenic elemental selenium nanoparticles using batch adsorption experiments. We measured ζ-potential values to assess the stability of nanoparticles loaded with Cd. Results show that the maximum Cd adsorption capacity amounts to 176.8 mg of Cd adsorbed per g of biogenic elemental selenium nanoparticles. The ζ-potential of Cd-loaded nanoparticles became less negative from ?32.7 to ?11.7 mV when exposing nanoparticles to an initial Cd concentration of 92.7 mg L^?1. This is the first study that demonstrates the high Cd uptake capacity of biogenic elemental selenium nanoparticles, of 176.8 mg g^?1, when compared to that of traditional adsorbents such as carboxyl-functionalized activated carbon, of 13.5 mg g^?1. An additional benefit is the easy solid–liquid separation by gravity settling due to coagulation of Cd-loaded biogenic elemental selenium nanoparticles.     

松涛水库水生生物农药污染水平及健康风险评价

在海南省松涛水库采集了鱼类和螺蛳共34个样品,利用气相色谱-质谱联用仪(GC-MS)检测样品中农药的浓度,并根据美国环境保护署(US EPA)的健康风险评价模型对松涛水库周围人群通过饮食途径摄入水生生物进行健康风险评价。结果表明,检测的29种农药,仅有7种在大部分样品中检出,分别为2,4-DDE、4,4-DDE、2,4-DDD、4,4-DDD、4,4-DDT、甲氧滴滴涕和甲基对硫磷,它们的平均含量(以湿重计)分别为0.32 ng·g~(~(-1))、3.68 ng·g~(~(-1))、0.17 ng·g~(~(-1))、1.33 ng·g~(~(-1))、0.90 ng·g~(~(-1))、1.34 ng·g~(~(-1))、0.32 ng·g~(~(-1))。鱼类肌肉以及螺蛳肉中农药的健康风险评价远远低于可承受水平,表明食用这些鱼类与螺蛳所造成的健康风险比较低。与其他研究相比,松涛水库的农药污染程度较轻。造成不同生物体间的农药含量差异的主要原因可能是牙叉库区的农药污染比南丰和番加库区的污染严重。     

Changes in soil organic matter composition after afforestation of arable farmland in northeast China

Since the 1970s, a substantial area of arable farmland in a semi-humid area of northeast China has been planted as deciduous forests (Populus tomentosa Carr.). This study investigates the effects of afforestation on soil organic carbon (SOC) content and the chemical composition of the soil. Soil samples (Calcic chernozem) were collected from the upper 10?cm of paired arable land and secondary forests established 5 and 25 years previously. Carbon isotope analysis and pyrolysis–gas chromatography/mass spectrometry were used to determine SOC composition. The results show that (i) compared to the arable land, five years of afforestation caused a decrease in SOC and N concentration, while 25 years of afforestation resulted in an increase in SOC content; (ii) stable isotope δ¹³C analyses of the forest soils show gradual loss of crop-derived C and an accumulation of forest-derived C; and (iii) afforestation increased lignin abundance and decreased decompositional activity in the 25-year-old forest topsoil. Higher amounts of short-/mid-chain aliphatic compounds were observed in the 5-year-old forest (5–10?cm); and (iv) the arable soil contained substantially higher amounts of decomposed plant material and microbially derived substances. The results obtained suggest that long-term afforestation increases the SOC concentration, and alters the chemical composition of SOC.     

Disaster prevention and reduction in Anthropocene

Natural disasters cause considerable property damage and loss of life as well as destruction of ecosystem and natural resources. In the context of global change, extreme events are expected to increase in both frequency and intensity. To prevent natural disasters and mitigate the loss, we need to act quickly and effectively. It would be conducive to achieve sustainable economic development, reduce disaster vulnerabilities and risks, and build resilience through implementing effective measures of disaster prevention, preparedness, response, and recovery.     

Enhanced adsorption of phosphate by loading nanosized ferric oxyhydroxide on anion resin

Ferric oxyhydroxide loaded anion exchanger （FOAE） hybrid adsorbent was prepared by loading nanosized ferric oxyhydroxide （FO） on anion exchanger resin for the removal of phosphate from wastewater. TEM and XRD analysis confirmed the existence of FO on FOAE. After FO loading, the adsorption capacity of the hybrid adsorbent increased from 38.70 to 51.52mg.g-1. Adsorption processes for both FOAE and anion resin were better fit to the pseudo first order model. Batch adsorption experiments revealed that higher temperature （313K）, higher initial phosphate concentration （50 mg.L-1） and lower solution pH （pH value of 2） would be more propitious to phosphate adsorption. Competition effect of coexisting anions on phosphate removal can be concluded as sulfate 〉 nitrate 〉 chloride. Freundlich isotherm model can describe the adsorption of phosphate on FOAE more accurately, which indicated the heterogeneous adsorption occurred on the inner-surface of FOAE.     

拟南芥基因组中注释为(S)-去甲乌药碱合成酶的分子克隆与异源表达(英文)

至今在拟南芥中尚未发现复杂生物碱,但是其基因组测序则表明有35个以上基因可编码(S)-去甲乌药碱合成酶(NCS).本研究首先以经过生化表征、机理清楚的来自罂粟、日本黄连、黄唐松草和花菱草的NCS为参考,与拟南芥中注释的NCS进行了广泛的生物信息学分析与比对,从中选择5个AtNCS为目的基因,设计特异性引物;从拟南芥中提取总RNA,一步法RT-PCR克隆得到上述基因;通过TA克隆将上述基因转入pGM-T载体,筛选、酶切及PCR鉴定,DNA测序验证它们的核酸序列;将测序验证的AtNCS基因经过PCR扩增、质粒构建、转入Escherichia coli BL21(DE3)中进行异源表达和蛋白纯化;在整体细胞、细胞裂解液、细胞裂解液上清和纯化蛋白共4个层次进行了AtNCS酶功能表征,未发现目标产物或新产物的生成;上述基因的具体功能还有待进一步研究.     

Hydroxyl radical generation and oxidative stress in Carassius auratus exposed to glyphosate and its formulation

Oxidative stress parameters and some antioxidant defense systems in the liver of Carassius auratus exposed to glyphosate and its formulation (Roundup®) have been studied. Fish were exposed to glyphosate and its formulation at concentrations of 0.032, 0.16, 0.8, and 4.0 mg L^?1, all calculated on glyphosate basis, for 11 days. Hydroxyl radical generation as determined by electron spin resonance spectroscopy of its spin-adduct with α-phenyl-t-butyl nitrone increased with the concentration of Roundup®. Superoxide dismutase activities were decreased relative to control by 21%–46% when exposed to glyphosate and 45%–52% when exposed to Roundup®, suggesting that the formulation is more toxic than glyphosate alone. Catalase showed no difference between both groups.     

全氟辛烷磺酸盐(PFOS)及替代品对两栖类蝌蚪的急性毒性

PFOS及其4种替代品对两栖动物非洲爪蟾和黑斑蛙蝌蚪的急性毒性结果为:用调聚法合成的织物三防整理剂对非洲爪蟾蝌蚪和黑斑蛙蝌蚪的96h-LC50分别为8和21mg·L-1,而PFOS对两种蝌蚪的96h-LC50分别为92和81mg·L-1。此实验结果说明织物三防整理剂的急性毒性高于PFOS。用电解氟化法合成的C4、C6织物三防整理剂和50%的全氟丁基有机铵盐阳离子表面活性剂浓度在100mg·L-1时,对两种蝌蚪都没有毒性。这说明,从急性毒性的角度,C4、C6织物三防整理剂和表面活性剂可作为PFOS的替代品使用,但是织物三防整理剂的急性毒性比PFOS大,作为替代品使用应慎重考虑。另外,PFOS和织物三防整理剂对黑斑蛙蝌蚪的急性毒性与对非洲爪蟾蝌蚪的急性毒性存在差异。出于保护我国本土两栖动物的目的,使用黑斑蛙开展毒性评价比使用非洲爪蟾更有现实意义。     

内置预分离复合式飞灰过滤器的开发与应用

针对飞灰过滤器除尘压降高、反吹清灰频繁、过滤元件破损、使用寿命短和大型化受到限制等问题,开发了内置旋风预分离复合式飞灰过滤器,并在工业装置上进行了应用,应用结果表明:过滤器压降明显降低、旋风分离器压降满足系统要求、延长了陶瓷滤芯的使用寿命、减少了因飞灰过滤器故障造成整个装置停车,同时,可带来直接经济效益约1 709万元/a、间接经济效益超过5 000万元。     

Effect of nitrogen deposition on China's terrestrial carbon uptake in the context of multifactor environmental changes

The amount of atmospheric nitrogen (N) deposited on the land surface has increased globally and by nearly five times in China from 1901 to 2005. Little is known about how elevated reactive N input has affected the carbon (C) sequestration capability of China's terrestrial ecosystems, largely due to the lack of reliable data on N deposition. Here we have used a newly developed data set of historical N deposition at a spatial resolution of 10 km x 10 km in combination with other gridded historical information on climate, atmospheric composition, land use, and land management practices to drive a process-based ecosystem model, the dynamic land ecosystem model (DLEM) for examining how increasing N deposition and its interactions with other environmental changes have affected C fluxes and storage in China's terrestrial ecosystems during 1901-2005. Our model simulations indicate that increased N deposition has resulted in a net C sink of 62 Tg C/yr (1 Tg = 1012 g) in China's terrestrial ecosystems, totaling up to 6.51 Pg C (1 Pg = 10(15) g) in the past 105 years. During the study period, the N-induced C sequestration can compensate for more than 25% of fossil-fuel CO2 emission from China. The largest C sink was found in southeast China, a region that experienced the most significant increase of N deposition in the period 1901-2005. However, the net primary productivity induced by per-unit N deposition (referred to as ecosystem N use efficiency, ENUE, in this paper) has leveled off or declined since the 1980s. This indicates that part of the deposited N may not be invested to stimulate plant growth, but instead leave the ecosystem by various pathways. Except shrubland and northwest/southwest China, signs of N saturation are apparent in the rest major biome types and regions, with ENUE peaking in the 1980s and leveling off or declining thereafter. Therefore, to minimize the excessive N pollution while keeping the N-stimulated C uptake in China's terrestrial ecosystems, optimized management practices should be taken to increase N use efficiency rather than to keep raising N input level in the near future.