贵阳酸雨中溶解态重金属质量浓度及形态分析

为了解酸雨地区雨水重金属的污染现状,季节性变化和形态分布特征,利用电感耦合等离子体质谱仪(ICP-MS)分析测试贵阳雨水中溶解态重金属的质量浓度,并在此基础上通过PHREEQC模型模拟雨水中重金属的形态分布特征.结果表明,贵阳雨水中溶解态重金属Co、Ni、Cu、Zn、Cd质量浓度较低未出现超标现象,秋季和冬季雨水中Pd质量浓度较高超过国家标准.雨水中Co和Ni主要来源于地壳,几乎没有受到人为影响;Cu、Zn、Cd和Pb受到了不同程度的人为污染,且秋和冬季的污染比春季和夏季更为严重.贵阳雨水中溶解态重金属主要是以自由离子态、草酸络合物和硫酸根络合物的形式存在,它们分别占总溶解态重金属的47.27%~95.28%、0.72%~51.87%和0.50%~7.66%.溶解态重金属的形态主要受雨水酸化程度、酸化类型和阴离子配体的浓度控制.     

柠檬酸对三峡水库消落区土壤中汞活化及甲基化的影响

利用室内模拟实验,用不同浓度柠檬酸溶液分别浸提和培养土壤,探讨了植被根系分泌物的主要成分柠檬酸对三峡库区消落带土壤中汞活化及甲基化的影响.结果表明,添加柠檬酸后浸提液中汞含量在达到最高值之前均高于对照组(0 mmol·L~(-1)),且随柠檬酸浓度的增加而增大.0、1、2、4、5、6、8 mmol·L~(-1)浓度下最大汞溶出量随柠檬酸浓度的增加先增大而后保持稳定,分别占供试土壤总汞的1.03%、1.67%、1.99%、2.47%、2.68%、2.73%、2.73%.培养实验中,土壤甲基汞(Me Hg)含量在前3 h内基本维持稳定,随后除对照组增加缓慢外,其余组均开始上升,且上升速率随柠檬酸浓度的升高而增大.在同一培养时段内,土壤Me Hg含量及增加量随柠檬酸浓度的升高而增大.表明柠檬酸对土壤中无机汞向甲基汞的转化过程有一定的促进作用,且促进作用随着柠檬酸浓度的增加而愈加显著.     

Evaluating sulfuric acid reduction,substitution, and recovery to improve environmental performance and biogas productivity in rubber latex industry

Sulfuric acid is heavily used in concentrated rubber latex factories to coagulate rubber particles in skim latex. The resulting sulfate-rich wastewater creates the onset of toxic H₂S gas production in the wastewater holding ponds, causing severe corrosion to materials and community disturbance when dispersed to ambient air. This work identified and evaluated measures to reduce H₂S production by minimizing sulfate concentration in the wastewater. Sulfuric acid use could be cut down by pre-removal of ammonia in the skim latex as well as a stricter manipulation of acid dosing. In search of a more benign chemical, a heat sensitive polymer was identified and tested as sulfuric acid substitute. The use of hydroxypropyl methylcellulose polymer (HPMC) changed wastewater characteristics and was found to increase biogas production approximately by 2.4 times in batch assay at the initial pH 7.0 and methane yield by 2.7 times in continuous digester operation at HRT 7 days. Finally, a resource recovery option was evaluated. The remaining H₂S in the produced biogas was oxidized in the biotrickling filter to sulfuric acid that has a potential to partially supplement the fresh acid. This work demonstrated an integrated approach in waste management to improve environmental performance, safety and energy recovery in the concentrated latex industry.     

短链氯化石蜡暴露对HepG2细胞代谢的影响

短链氯化石蜡(short-chain chlorinated paraffins,SCCPs)是一组成分复杂的氯代正构烷烃,在环境中普遍存在。然而有关其毒性机理的信息十分有限,限制了对其健康风险的评估。本研究采用液相色谱–串联质谱(LC-MS/MS)分析技术,研究了不同剂量的SCCPs暴露(0、1.0、10.0和100.0μg·L-1;C13-CPs;55.0%Cl)对人体肝癌细胞Hep G2的糖代谢、氨基酸代谢和脂肪酸代谢的影响。通过偏最小二乘判别分析(PLS-DA)鉴别各组代谢产物谱差异,发现3个SCCPs暴露剂量组均能够与对照组完全分开,表明SCCPs短期暴露能够引起细胞代谢活动的显著改变。SCCPs的低剂量暴露可明显刺激Hep G2细胞对氨基酸的吸收。与对照组相比,SCCPs低剂量暴露组(1.0μg·L-1)培养基中谷氨酰胺、色氨酸和丝氨酸的含量显著(P0.05)降低。而高剂量SCCPs(100.0μg·L-1)暴露抑制了细胞对氨基酸和葡萄糖吸收,但促进了乳酸、丙氨酸、半胱氨酸的生成。氨基酸吸收的抑制不可避免地会影响蛋白质的合成。同时,SCCPs的暴露使饱和脂肪酸代谢紊乱,使不饱和脂肪酸水平上调。为确定SCCPs的毒性作用方式,有必要从转录组和蛋白组层面进一步研究其毒性机制。     

Review on the study of mercury/silver ions-pyrimidine base pairs in DNA duplexes and their application in detection technology北大核心CSCD

Nucleic acids and their analogues are getting more and more attention. Metal-mediated base pairs as a kind of simple and functionalized nucleic acids in special positions have widened the scope of application of functional nucleic acids and their analogues. In this type of base pairs, the representative is the interaction between metal ions and pyrimidine bases, especially the research on thymine-Hg2+-thymine (T-Hg2+-T) and cytosine-Ag+-cytosine (C-Ag+-C) base pairs. This review summarizes the structure and mechanism of metal-mediate pyrimidine base pairs as well as the application in the biochemical analysis. It explores the mode and ratio of coordination between metal ions and base pairs, the effects on the stability of DNA helical structure, the related crystal structure and the three-dimensional configuration information in the DNA helix. The analytical application mainly includes various probes of metal ions, small molecules, protein and the detection of single nucleotide polymorphism. Among them the most widely used metal ions detection, and its combination with spectrum technology, visualization and amplification technology greatly promoted the rapid development of sensitive detection technology. In further studies, it is necessary to reveal the mechanism of interaction between T-Hg2+-T and C-Ag+-C, and more attention should be paid to combining of T-Hg2+-T and C-Ag+-C base pairs with other new technologies. The scope of practical application should also be further extended.     

Variation in soil organic carbon mineralization and microbial community structure induced by the conversion from double rice fields to drained fields北大核心CSCD

Land use conversion is an important factor influencing the carbon gas exchange between land and atmosphere. The effect of land use conversion on soil organic carbon mineralization and microbial function is important for soil organic carbon sequestration and stability. This research studied the effects of land use conversion on soil chemical properties, organic carbon mineralization and microbial community structure after two years of conversion from double rice cropping (RR) to maize-maize (MM) and soybean-peanut (SP) double cropping systems in southern China. The results showed that soil pH significantly decreased by 0.50 (MM) and 0.52 (SP, P = 0.002), and dissolved organic carbon significantly increased by 23%- 35% (P = 0.016). No significant difference was found in soil organic carbon mineralization rate with the land use conversion, though the accumulated mineralization decreased after 13 days of incubation (P = 0.019). Land use conversion from paddy to upland significantly changed soil microbial community structure. The total PLFAs, bacterial, gram-positive bacterial (G+), gram-negative bacterial (G-) and actinomycetic PLFAs decreased significantly (P < 0.05), the ratio of fungal PLFAs to bacterial PLFAs (F/B) increased significantly (P = 0.006). But no significant differences in microbial groups were found between MM and SP. The accumulated mineralization at the beginning period of the incubation were significantly positively correlated with soil actinomycetic PLFAs (P = 0.034). After 13 days of incubation, soil F/B showed a positive correlation with the accumulated mineralization (P = 0.004). However, soil microbial community structure(P = 0.014)and total PLFAs(P = 0.033)showed a positive correlation with the accumulated mineralization after 108 days of incubation. Our results indicated that after conversion from paddy soils to drained soils, soil pH and total nitrogen are the key factors regulating the variations in soil microbial community structure and biomass, and then influencing soil organic carbon mineralization.     

Toxic effects of perfluorononanoic acid on the development of Zebrafish (Danio rerio) embryos

Perfluorononanoic acid (PFNA) is a nine-carbon perfluoroalkyl acid widely used in industrial and domestic products. It is a persistent organic pollutant found in the environment as well as in the tissues of humans and wildlife. There is a concern that this chemical might be a developmental toxicant and teratogen in various ecosystems. In the present study, the toxic effects of PFNA were evaluated in zebrafish (Danio rerio) embryos. One hour post-fertilization embryos were treated with 0, 25, 50, 100, 200, 300, 350, and 400 μmol/L PFNA for 96 hr in 6-well plates. Developmental phenotypes and hatching rates were observed and recorded. Nineteen genes related to oxidative stress and lipid metabolism were examined using Quantitative RT-PCR and confirmed by whole mount in situ hybridization (WISH). Results showed that PFNA delayed the development of zebrafish embryos, reduced the hatching rate, and caused ventricular edema and malformation of the spine. In addition, the amount of reactive oxygen species in the embryo bodies increased significantly after exposure to PFNA compared with that of the control group. The Quantitative RT-PCR and WISH experiments demonstrated that mRNA expression of the lfabp and ucp2 genes increased significantly while that of sod1 and mt-nd1 decreased significantly after PFNA exposure. The mRNA expression levels of gpx1 and mt-atp6 decreased significantly in the high concentration group. However, the mRNA expression levels of both ppara and pparg did not show any significant variation after exposure. These findings suggest that PFNA affected the development of zebrafish embryos at relatively low concentrations.     

Fenton 试剂处理草酸化工废水的实验研究

利用Fenton工艺对草酸化工废水进行预处理,试验结果表明：针对该废水,温度为制约其反应的最重要的影响因素,升温至40℃时,可达到最佳处理效果;Fenton预反应后可能出现pH不升反降的现象,pH＝3时处理效果较好;对沉淀时间较长的间歇式处理,絮凝剂PAM的投加意义不大。试验表明,在温度为40℃,pH＝3,投加2％的双氧水（双氧水和硫酸亚铁的摩尔比为1：4）时,COD总去除率可达到78％。     

工业废气中异丁酸的测定

建立了用离子色谱法测定工业废气中异丁酸的新方法。废气中异丁酸经淋洗液吸收,0．45μm微孔滤膜过滤后离子色谱法分析,时间定性,峰高定量,其异丁酸回收率为93．5％～104．2％,消采样体积为20L的条件下,异丁酸最低检出质量浓度为0．02mg／m^3。