Behaviors of dissolved antimony in the Yangtze River Estuary and its adjacent waters

Antimony is a naturally occurring and cumulatively toxic element. With increasing concern as an inorganic contaminant, research on its environmental behavior is becoming a necessity. However, very little is known about this element. To further understand its biogeochemical behaviors and roles in the ecosystem, the main species of dissolved inorganic antimony (Sb(iii) and Sb(v)) in Yangtze River Estuary and its adjacent waters were determined by hydride generation and atomic fluorescence (HG-AFS) in our study. Results show that in surface water, the concentration for Sb(iii) and Sb(v) were in the range 0.029 μg L(-1)～ 0.736 μg L(-1) and 0.121 μg L(-1)～ 2.567 μg L(-1), with averages of 0.152 μg L(-1) and 0.592 μg L(-1), respectively. While concentrations of Sb(iii) and Sb(v) in the bottom layer were much lower, ranging from 0.023 μg L(-1) to 0.116 μg L(-1) (average of 0.050 μg L(-1)) and from 0.047 μg L(-1) to 0.441 μg L(-1) (average of 0.194 μg L(-1)), respectively. Data analysis further demonstrates that the major processes controlling antimony geochemistry in the area are riverine input, atmospheric deposition, incursion of Taiwan Warm Current, and release from particulate phase. The surface-enrichment and bottom-depletion depth profile reveals it does appear as a mildly scavenged element but is less like arsenic than previously believed. Sb(v) was the predominant speciation in aquatic environment of our research, and Sb(iii) was a minor constituent of the total antimony. Regarding the adsorption-desorption process onto SPM, Sb(iii) has a higher affinity to particulate phase than Sb(v). Furthermore, the significant correlation between antimony and nutrients indicates it is an element with great biological potential, which is also an important behavior for antimony.     

Magnetic microsphere confined ionic liquid as a novel sorbent for the determination of chlorophenols in environmental water samples by liquid chromatography

Magnetic microsphere confined ionic liquid was synthesized by covalently bonding N-methylimidazolium on magnetic microspheres. The functionalized magnetic microspheres were characterized by Fourier transform infrared (FT-IR) spectrometry, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The prepared material was used for the preconcentration of three chlorophenols (CPs) in water combined with high-performance liquid chromatography (HPLC). Several conditions that probably affected the extraction efficiency such as standing time, eluent and its volume, sample pH and volume, were optimized. Under the optimal conditions, good recoveries (70.3-88.8%) were achieved with satisfactory relative standard deviations (RSDs) of less than 6.0%. The limits of detection for the three CPs were 0.20-0.35 μg L(-1). The results indicated that the ionic liquid-functionalized magnetic microspheres show significant promise for the analysis of CPs in environmental samples.     

Fungal DNA and pet allergen levels in Swedish day care centers and associations with building characteristics

Pet allergens and mold growth related to damp are common phenomena in day care centers in Sweden but exposure measurements of these factors are lacking. The aim of this study was to investigate the relationship between building construction and indoor environment quality in Swedish day care centers and the potential for exposure to fungi (analyzed by quantitative PCR) and animal allergens (analyzed by ELISA). Measurements were performed in 21 day care centers (103 rooms) from one municipality in Sweden, which were identified as constructions at risk of dampness (85% of the buildings) and with visible damage and mold growth (54% of the buildings). Dust samples were collected using cotton swab and Petri dishes. Total fungal DNA was detected in 99% and 100%, Aspergillus/Penicillium DNA in 54% and 68%, and Stachybotrys chartarum DNA in 4% and 9% of the investigated rooms in cotton swab and Petri dish samples, respectively. The total fungal DNA levels (Geometric Mean, GM) were 4.2 × 10(6) cell equivalents per m(2) and 2.9 × 10(5) cell equivalents per m(2) per day in the swab and Petri dish samples, respectively. The concentrations (GM) of cat (Fel d1), dog (Can f1), and horse (Equ cx) allergens were 9.4, 7.2 ng m(-2) day(-1), and 5.0 unit per m(2) per day, respectively. Total fungal DNA levels were higher in risk construction buildings (p = 0.01), in rooms with linoleum flooring material (p = 0.003), and in buildings with rotating heat exchangers (p = 0.02). There were associations between total fungal DNA levels and cat (p = 0.02), dog (p < 0.001), and horse (p = 0.001) allergens. In conclusion, risk constructions, damp constructions, mould growth, fungal DNA, and animal allergens were common exposure factors in Swedish day care centers. Building constructions that represent a high risk for internal dampness should be avoided in the future, and measures to reduce allergen levels should be considered to protect pet-allergic children from asthmatic problems.     

陕西省精细化地质灾害气象预报预警研究

在黄土高原和秦巴山区地质灾害与降水相关特征分析基础上,介绍了陕西省气象台精细化地质灾害气象预报预警模型与业务系统.利用新一代多普勒天气雷达和自动气象站加密资料实现了综合雨量的精细估计,结合GIS地形地貌信息和历史灾害风险分析确定出降水影响系数后,通过计算指标量与灾害临界阈值判断实现了陕西省l 915个乡镇地质灾害的逐日...     

内蒙古中西部地区土壤紧实度初步研究

沙尘暴的发生与沙尘暴源地的下垫面状况密不可分,下垫面要素中土壤紧实度等地表状况指标是沙尘暴灾害下垫面因子的危险度研究的重要内容。选取沙尘暴源地的内蒙古中西部地区为研究区域,于2004年4月进行了土壤紧实度实地采样,对获取的36个采样点的数据进行了统计分析,发现在不同的植被覆盖类型下,地表的土壤紧实度值具有明显的分异特征和分布范围。以1∶10万的内蒙古土地利用类型图为依托进行重分类,对研究区域的土壤紧实度值进行空间上的了反演。并通过2009年第二次实地采样对该反演的精度进行了验证,排除干扰因素后,发现土壤紧实度的反演结果良好,因此可以获得空间范围上土壤紧实度的一个粗略范围值。研究结果可为日后进行土壤紧实度对沙尘暴的影响和贡献等级划分以及沙尘暴下垫面脆弱性风险评估和区划提供数据支持。     

模拟升温和放牧对高寒草甸土壤微生物群落的影响

通过开顶式温室(Open top chambers,OTCs)升温以及刈割+施加牛粪处理,应用磷脂脂肪酸(Phospholipid fatty acids,PLFAs)方法,研究了青藏高原东部高寒草甸土壤微生物群落结构对气候变暖和放牧的响应.结果表明,高寒草甸在生长季节,微生物群落以细菌为主.平均1.17℃的土壤升温使土壤微生物PLFAs总量增加34.58%,而春季割草结合牛粪施加使微生物PLFAs总量增加65.77%.模拟变暖和放牧均引起土壤微生物群落结构的显著变化.升温使细菌相对含量增加8.80%,而使真菌相对含量降低17.48%,细菌与真菌之比由7.3变为9.6.放牧使细菌相对含量增加8.40%,真菌相对含量降低14.04%,细菌与真菌之比由7.3变为9.2.OTCs升温+放牧处理比单独的升温或放牧处理对土壤微生物总量和细菌与真菌比值的影响更加明显.本研究表明,气候变暖和人类活动能够在短期内显著地改变青藏高原高寒草甸土壤微生物群落结构,进而可能影响这一地区的生态系统碳收支和养分循环.     

天津南港工业区土壤环境背景值调查

通过对天津南港工业区土壤环境背景值的调查研究,对其土壤进行了环境质量评价,并得出了该区域土壤元素的分布规律。在与其他地区的土壤背景值进行比较后,指出了其异同点。天津南港工业区土壤元素在垂直方向上以不规则分布型为主,但As和Cd在土壤表层和深层的含量变化差异较小,Pb表现为表层富集。水平方向上,园区西北部的土壤元素含量比...     

重组大肠杆菌产CotA漆酶的发酵条件优化

CotA漆酶在环境保护、食品工业和纸浆漂白等工业中具有重要的应用价值.将重组表达载体pET-22b/CotA转入大肠杆菌BL21(DE3),得到工程菌株,采用单因素实验和正交实验相结合的方法,研究诱导表达条件和发酵培养基对重组大肠杆菌产CotA漆酶量的影响.结果表明,初始pH 7.5的培养基中,添加0.6 mmol L-1 Cu2+,1 g L-1葡萄糖作碳源、15 g L-1蛋白胨和2 g L-1硫酸铵作氮源,以10%的接种量,37℃、200 r/min,直到菌液的D600 nm值为1.0,加入终浓度为1.0 mmol L-1的IPTG,25℃诱导12 h,漆酶的产量最高.优化前发酵液的粗提液的漆酶活性仅为1 190 U mL-1,优化后达到3 526 U mL-1,正交实验优化后漆酶活性提高了2.96倍.纯化的CotA漆酶最适反应温度为45℃,最适pH值为7.2.CotA漆酶对RBBR的脱色率在90%以上,此CotA漆酶在短时间内对染料能够有效地脱色,能够成为有潜力的工业用酶.图6表3参17     

A dynamic Bayesian networks modeling of human factors on offshore blowouts

An application of dynamic Bayesian networks for quantitative risk assessment of human factors on offshore blowouts is presented. Human error is described using human factor barrier failure (HFBF), which consists of three categories of factors, including individual factor barrier failure (IFBF), organizational factor barrier failure (OFBF) and group factor barrier failure (GFBF). The structure of human factors is illustrated using pseudo-fault tree, which is defined by incorporating the intermediate options into fault tree in order to eliminate the binary restriction. A methodology of translating pseudo-fault tree into Bayesian networks and dynamic Bayesian networks taking repair into consideration is proposed and the propagation is performed. The results show that the human factor barrier failure probability only increases within the first two weeks and rapidly reaches a stable level when the repair is considered, whereas it increases continuously when the repair action is not considered. The results of mutual information show that the important degree sequences for the three categories of human factors on HFBF are: GFBF, OFBF and IFBF. In addition, each individual human factor contributes different to the HFBF, those which contribute much should given more attention in order to improve the human reliability and prevent the potential accident occurring.     

基于多需求点的震灾应急物资调度模型研究

为了解决震后应急物资调度中,因不考虑各应急需求点灾情差异和需求差异带来的决策结果不够合理的问题,采用改进的专家打分法将收集到的灾情信息量化为灾情因子,在此基础上建立应急成本和应急延误时间的多目标模型。采用逐步法求解,为每一个应急需求点确定提供应急物资的供应点及供应量。将此方法运用到云南发生的某地震灾后救援中,计算得出与3个应急需求点对应的应急供应点及其供应量。