南方灵芝子实体的化学成分

南方灵芝[Ganoderma australe(Fr.)Pat.,Bull.]为一种常见的生长在阔叶树枯立木、倒木和伐桩上的灵芝属真菌,具有很好的药用和保健价值.采用硅胶、凝胶柱色谱、反相ODS柱和高效液相色谱等方法从野生南方灵芝子实体的乙醇提取物中分离到14个化合物,结合核磁共振(1H-NMR,13C-NMR)、质谱(MS)、红外(IR)、紫外(UV)等波谱技术将其分别鉴定为灵芝烯酸G甲酯(Methyl ganoderenate G,1)、灵芝烯酸G(Ganoderenic acid G,2)、灵芝烯酸A(Ganoderenic acid A,3)、灵芝烯酸A甲酯(Methyl ganoderenate A,4)、灵芝烯酸D(Ganoderenic acid D,5)、灵芝烯酸F(Ganoderenic acid F,6)、灵芝酸AP(Ganoderic acid AP,7)、7β,23α-dihydroxy-3,11,15-trioxolanosta-8,20E(22)-dien-26-oic acid(8)、Elfvingic acid A(9)、3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6-one(10)、对羟基苯甲酸(p-hydroxybenzoic acid,11)、3-羟基-4-甲氧基苯甲酸(3-hydroxy-4-methoxybenzoic acid,12)、油酸-α-单甘油酯(9-octadecenoic acid-2,3-dihydroxypropyl ester,13)及谷甾醇(β-sitosterol,14).其中,化合物1为新化合物,化合物1-9为从南方灵芝中首次分离得到的羊毛甾烷型三萜化合物.     

四氯丙烯对稀有鮈鲫的急性毒性及安全浓度评价

采用半静态试验方式测试了四氯丙烯对稀有鮈鲫(Gobiocypris rarus)的急性毒性,试验浓度分别设定为0.25 mg·L~(-1)、0.30mg·L~(-1)、0.36 mg·L~(-1)、0.42 mg·L~(-1)、0.50 mg·L~(-1)和0.60 mg·L~(-1),同时进行空白对照(试验用水)和分散剂对照(体积分数为0.006%的吐温-80水溶液)试验。采用气相色谱法对试验溶液进行浓度分析,实测浓度分别为0.19 mg·L~(-1)、0.25 mg·L~(-1)、0.34 mg·L~(-1)、0.40 mg·L~(-1)、0.51 mg·L~(-1)和0.64 mg·L~(-1),试验结果以实测浓度表示和统计。结果表明:四氯丙烯致稀有鮈鲫无死亡发生(EC0)的最高浓度为0.25 mg·L~(-1),导致稀有鮈鲫100%死亡(EC100)的最低浓度为0.51 mg·L~(-1)。根据实测浓度,用SPSS(17.0)概率单位法求得四氯丙烯对稀有鮈鲫的半数致死浓度96 h-LC50为0.347 mg·L~(-1),95%置信区间为0.328 mg·L~(-1)~0.361 mg·L~(-1)。     

Soil microbial response to waste potassium silicate drilling fluid

Potassium silicate drilling fluids (PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥ 40 m³/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments. Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils.     

Sulfide elimination by intermittent nitrate dosing in sewer sediments

The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards, and requires expensive programs for its prevention. The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments. The study was carried out based on lab-scale experiments and batch tests using real sewer sediments. The intermittent nitrate dosing mode and the optimal control condition were investigated. The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment. The oxidation–reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S(nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions of efficient sulfide control with lower carbon source loss. The optimal control condition is feasible for the sulfide elimination in sewer systems.     

对核磁共振成像仪建设项目环境影响评价的研究

核磁共振作为一种分析手段广泛应用于物理、化学、生物、医疗等领域.本文从核磁共振原理出发,分析核磁共振成像仪主要环境影响,结合环评现状,分析环评管理存在的主要问题,结合相关法规条文,查找存在这些问题的主要原因,结合目前核磁共振仪的建设情况和使用条件,从切合实际角度出发,提出核磁共振成像仪建设项目环评管理建议.     

安徽北部农村地区地下水重金属健康风险评价

为了解安徽北部农村地区地下水重金属污染对人类健康产生危害的风险,采集了26个农村地下水样品,测试分析了Mn、Zn、Cu、Pb、Ni、Cr和Cd七种重金属,并采用美国环境保护局(USEPA)推荐的风险评价模型对健康风险进行了初步评价。结果表明:非致癌污染物Mn、Zn、Cu、Pb和Ni的平均个人年风险分别为1.21×10~(-10)a~(-1)、8.46×10~(-11)a~(-1)、2.93×10~(-10)a~(-1)、8.29×10~(-10)a~(-1)和2.89×10~(-10)a~(-1),均远低于国际辐射防护委员会(ICRP)推荐的最大可接受值(5.0×10~(-5)a~(-1))和USEPA推荐的健康风险等级标准(1×10~(-4)a~(-1)),基本不会对暴露人群构成明显危害;致癌污染物Cd和Cr饮水途径健康危害平均个人年风险分别为1.44×10~(-6)a~(-1)和1.93×10~(-5)a~(-1),超出瑞典环境保护署、荷兰建设与环境部和英国皇家协会推荐标准(1×10~(-6)a~(-1)),Cr甚至超出19倍,为研究区首要污染物,应引起环境卫生部门的重视。     

典型河谷城市儿童土壤与灰尘铅暴露风险

为定量评价河谷型城市土壤与灰尘铅对城市儿童健康的影响与风险,结合野外调查的基础上,以陕西渭河谷地典型工业城市宝鸡、西安、渭南和铜川为研究区域,以定量分析河谷型城市儿童环境铅暴露为核心,收集4个城市土壤与灰尘分析样品总计243个。利用X射线荧光光谱法测定了4个城市土壤与灰尘铅的含量;采用BCR连续形态分级法探究了城市土壤与灰尘重金属铅地球化学形态分布与迁移特征;根据US EPA污染物暴露与健康风险评价模型对城市儿童铅暴露进行了评价。研究结果表明渭河谷地典型城市宝鸡、铜川、西安和渭南城市土壤与灰尘铅浓度(X±SD)分别为(409.2±52.54)和(624.70±66.15)mg·kg-1、(357.47±41.37)和(592.60±36.78)mg·kg-1、(61.4±13.31)和(78.42±14.89)mg·kg-1、(46.71±12.11)和(64.7±13.76)mg·kg-1,均高出陕西省土壤铅背景值;污染水平依次为宝鸡铜川西安渭南。4个河谷型城市土壤与灰尘重金属铅发生整体迁移的趋势为:宝鸡城市灰尘(90.71%)西安城市灰尘(84.74%)≥宝鸡城市土壤(83.12%)渭南城市灰尘(74.89%)≥西安城市土壤(74.50%)铜川城市灰尘(72.49%)铜川城市土壤(57.50%)渭南城市土壤(53.79%)。可见,铅在均在城市灰尘中的迁移趋势远大于相应的城市土壤。4个城市土壤与灰尘均表现出较大的儿童暴露致癌风险,宝鸡和铜川城市儿童土壤与灰尘铅暴露也分别存在非致癌风险,风险程度依次为宝鸡铜川西安渭南。儿童铅暴露致癌与非致癌风险程度与其城市土壤和灰尘中铅可氧化态分布呈相似的规律,表明碱性的城市土壤与城市灰尘(p H7)中可氧化态铅可能是导致河谷型城市儿童铅暴露风险和儿童血铅污染的主要形态和因素。由此,城市燃煤排放与含铅制品的加工等活动可能是渭河谷地河谷型城市儿童血铅与铅暴露最主要的贡献源,必须采取长期有效的监测与控制措施。     

关于焦化行业CO2排放核算方法的探讨

本文分析了适用于焦化行业通用CO₂排放核算方法,在此基础上结合我国焦化行业工艺和原料的特征,采用排放因子法和物料衡算法等两种方法对10家典型焦化企业CO₂排放进行核算。结果表明:物料衡算法能很好地反映不同类型焦化企业的排放特征;排放因子法对我国独立焦化企业存在碳排放量系统性高估的可能。为此,建议我国焦化企业可借鉴德国焦化企业的碳核算经验,采用碳平衡法对不同类型的焦化企业(单元)的碳排放量进行核算,并完善相关的统计和监测技术。     

Extracellular polymeric substance induces biogenesis of vivianite under inorganic phosphate-free conditions

Vivianite is often found in reducing environments rich in iron and phosphorus from organic debris degradation or phosphorus mineral dissolution. The formation of vivianite is essential to the geochemical cycling of phosphorus and iron elements in natural environments. In this study, extracellular polymeric substances (EPS) were selected as the source of phosphorus. Microcosm experiments were conducted to test the evolution of mineralogy during the reduction of polyferric sulfate flocs (PFS) by Shewanella oneidensis MR-1 (S. oneidensis MR-1) at EPS concentrations of 0, 0.03, and 0.3 g/L. Vivianite was found to be the secondary mineral in EPS treatment when there was no phosphate in the media. The EPS DNA served as the phosphorus source and DNA-supplied phosphate could induce the formation of vivianite. EPS impedes PFS aggregation, contains redox proteins and stores electron shuttle, and thus greatly promotes the formation of minerals and enhances the reduction of Fe(III). At EPS concentration of 0, 0.03, and 0.3 g/L, the produced HCl-extractable Fe(II) was 107.9, 111.0, and 115.2 mg/L, respectively. However, when the microcosms remained unstirred, vivianite can be formed without the addition of EPS. In unstirred systems, the EPS secreted by S. oneidensis MR-1 could agglomerate at some areas, resulting in the formation of vivianite in the proximity of microbial cells. It was found that vivianite can be generated biogenetically by S. oneidensis MR-1 strain and EPS may play a key role in iron reduction and concentrating phosphorus in the oligotrophic ecosystems where quiescent conditions prevail.     

The role of doped-Mn on enhancing arsenic removal by MgAl-LDHs

To meet the challenges posed by global arsenic water contamination, the MgAlMn-LDHs with extraordinary efficiency of arsenate removal was developed. In order to clarify the enhancement effect of the doped-Mn on the arsenate removal performance of the LDHs, the cluster models of the MgAlMn-LDHs and MgAl-LDHs were established and calculated by using density functional theory (DFT). The results shown that the doped-Mn can significantly change the electronic structure of the LDHs and improve its chemical activity. Compared with the MgAl-LDHs that without the doped-Mn, the HOMO-LUMO gap was smaller after doping. In addition, the -OH and Al on the laminates were also activated to improve the adsorption property of the LDHs. Besides, the doped-Mn existed as a novel active site. On the other hand, the MgAlMn-LDHs with the doped-Mn, the increased of the binding energy, as well as the decreased of the ion exchange energy of interlayer Cl⁻, making the ability to arsenate removal had been considerably elevated than the MgAl-LDHs. Furthermore, there is an obvious coordination covalent bond between arsenate and the laminates of the MgAlMn-LDHs that with the doped-Mn.