贵州浓香型白酒大曲中霉菌的18S rDNA系统发育分析

从贵州某名酒厂大曲中分离到104株丝状真菌(霉菌),通过形态特征和生理特性检测等传统鉴定方法,初步把形态和生理生化特征一致的霉菌归类为14个大类群;并采用18S rDNA序列分析,进一步把菌株归类为MJ-I至MJ-V五个类群,随后构建系统发育树.结果表明,样品中的霉菌以曲霉属(Aspergillus)为主,占总分离菌数...     

桂林岩溶表层带土壤CO2体积分数时空变化规律及其意义

通过2010—2011年的监测建立了桂林盘龙洞坡地和洼地不同深度土壤CO2体积分数的季节性变化。监测土壤CO2体积分数空间上变化为:坡地80 cm>50 cm>30 cm;洼地80 cm>100 cm>50 cm>30 cm。监测土壤CO2体积分数时间上变化为2010年7月和2011年6月未CO2体积分数达到最高值,2010到2011年冬季为土壤CO2达到最低值。由于受到大气降水量急剧减少的影响2011年土壤CO2体积分数整体比2010年低。显示大气降水量也是影响土壤CO2体积分数的重要环境因素。为我国固碳减排科学的选择时间和空间提供有力的依据。     

Enhanced atrazine removal using membrane bioreactor bioaugmented with genetically engineered microorganism

Bioaugmentation with genetically engineered microorganisms (GEMs) in a membrane bioreactor (MBR) for enhanced removal of recalcitrant pollutants was explored. An atrazine-degrading genetically engineered microorganism (GEM) with green fluorescent protein was inoculated into an MBR and the effects of such a bioaugmentation strategy on atrazine removal were investigated. The results show that atrazine removal was improved greatly in the bioaugmented MBR compared with a control system. After a start-up period of 6 days, average 94.7% of atrazine was removed in bioaugmented MBR when atrazine concentration of influent was 14.5 mg/L. The volumetric removal rates increased linearly followed by atrazine loading increase and the maximum was 65.5 mg/(L·d). No negative effects were found on COD removal although carbon oxidation activity of bioaugmented sludge was lower than that of common sludge. After inoculation, adsorption to sludge flocs was favorable for GEM survival. The GEM population size initially decreased shortly and then was kept constant at about 10⁴–10⁵ CFU/mL. Predation of micro-organisms played an important role in the decay of the GEM population. GEM leakage from MBR was less than 10² CFU/mL initially and was then undetectable. In contrast, in a conventionally activated sludge bioreactor (CAS), sludge bulking occurred possibly due to atrazine exposure, resulting in bioaugmentation failure and serious GEM leakage. So MBR was superior to CAS in atrazine bioaugmentation treatment using GEM.     

Metals and metalloids in PM10 in Nandan County,Guangxi, China,and the health risks posed

Intense mining, smelting, and tailing activities of polymetallic ore deposits have affected the environment in Nandan County, Guangxi, China. Samples of particulates with aerodynamic diameters low or equal 10 μm (PM₁₀) were collected in Nandan County to investigate the concentrations of and health risks posed by 17 metals and metalloids in the PM₁₀. The metal and metalloid concentrations were lower than those found in other industrial cities. The mean Cr concentration was 7.48 ng/m³. Significant higher metal and metalloid concentrations were found in PM₁₀ from mining areas (Dachang and Chehe) than from the control area (Liuzhai) (p < 0.05). Principal component analysis indicated that the main sources of Ba, Co, Cr, Fe, K, Mg, Mo, Na, and Sr were resuspension of the soil produced through mineral erosion, the main sources of As, Cd, Cu, Pb, Sb, and Zn were smelting and mining activities, and the main source of Ni was fossil fuel combustion. Higher non-carcinogenic and carcinogenic risks were posed in Dachang and Chehe than in Liuzhai. The non-carcinogenic risks posed to adults and children by individual metals and metalloids in PM₁₀ at all the sites were low, but the non-carcinogenic risks posed to children by all the metals and metalloids together exceeded the safe level (i.e., risk value > 1). The carcinogenic risks posed by Cd, Ni, and Pb were negligible at all sites, while As, Co, and Cr posed potential carcinogenic risks to the residents.

     

畜禽抗生素对植物的生态毒理效应综述

随着畜禽规模化养殖的发展,畜禽抗生素用量不断增加,且随着畜禽粪便扩散到土壤、水体中;植物吸收、积累并转化抗生素,从而对植物生长和生理代谢产生影响。本文综述了畜禽抗生素应用及污染现状,详述了近年来四环素类、磺胺类和喹诺酮类等畜禽抗生素对大田作物、蔬菜果树、湿地植物、农田杂草、水生植物及藻类的种子萌发、根、叶的形态和生理代谢的生态毒理效应的研究进展,着重综述了畜禽抗生素对这些植物光合作用和抗氧化系统的生态毒理效应的研究进展。以期为污水的植物修复、粮食蔬菜的生物安全以及生态环境安全提供科学依据。     

浅析温室效应及控制对策

由于近年来人口激增、人类活动频繁,矿物燃料用量猛增,再加上森林植被破坏,大气中的温室气体含量不断增加,造成了温室效应加剧,将会导致全球变暖,海平面升高,给生态环境及人类健康等多方面带来影响。只有设法减少燃料的使用量,开发新能源,广泛植树造林,禁止砍伐森林,有效地控制人口,才能减缓温室效应的加剧。     

磺胺嘧啶和泰乐菌素对养猪废水硝化作用的差异性影响

养猪废水中高残留抗生素会对废水处理系统中的微生物功能产生影响,而由微生物主导的硝化作用是养猪废水脱氮首要环节。为解析抗生素对养猪废水处理系统中硝化反应的影响机制,选取磺胺嘧啶(SDZ)和泰乐菌素(TYL)为代表性抗生素,对比研究了2种典型抗生素不同暴露水平下养猪废水好氧污泥体系氨氧化和硝化反应的变化规律,并结合扩增子测序分析了2种抗生素对硝化反应功能微生物的影响差异。结果表明,在环境浓度下(100～1 000 μg·L^-1)SDZ和TYL对体系氨氧化速率均具有显著抑制作用且与抗生素暴露浓度正相关,1 000 μg·L^-1浓度抗生素试验组中氨氮去除率最高分别下降72%和65%,同时显著降低了体系中微生物丰富度和多样性,抗生素作用时间的影响大于浓度的影响。相比TYL,SDZ对细菌和氨氧化功能菌群结构产生显著影响。SDZ主要显著抑制了亚硝化单胞菌目(Nitrosomonadales)、亚硝化单胞菌科(Nitrosomonadaceae)和亚硝化单胞菌属(Nitrosomonas)等硝化功能菌群。本研究结果为揭示抗生素的环境效应提供基础数据。     

湘中黑色页岩风化土壤稀土元素分布特征及环境风险评价

稀土元素（REY,REEs+Y）是一种环境污染物. 本研究利用电感耦合等离子质谱仪( ICP-MS)对湘中地区下寒武统新鲜黑色页岩（FBS）、风化黑色页岩（WBS）和黑色页岩土壤（BSS）中稀土元素含量进行了分析,探讨黑色页岩风化土壤稀土元素活性特征及富集机制,评估黑色页岩发育土壤稀土元素污染程度及潜在生态风险. 结果表明,湘中黑色页岩发育土壤稀土元素含量较高,稀土元素总量（ΣREY）为黑色页岩发育土壤（297.5 mg·kg⁻¹）>风化黑色页岩（236.7 mg·kg⁻¹）>新鲜黑色页岩（164.4 mg·kg⁻¹）. 北美页岩标准化配分模式为呈右倾分布的页岩型配分模式,表现为轻稀土富集（(La/Sm)_N、(La/Yb)_N、(Gd/Yb)_N的平均值均大于1）. 稀土元素质量迁移系数（τ）计算结果显示,相对于新鲜黑色页岩,风化黑色页岩及黑色页岩发育土壤τ值为-0.31 — 1.36、-0.38 — 0.30,大都大于0,说明黑色页岩风化过程稀土元素主要表现为次生富集,且中稀土富集程度更高. 风化过程中原生稀土矿物的溶解及成土过程黏土矿物和有机质对稀土元素的强烈吸附是黑色页岩发育土壤富集稀土元素的重要原因. 地累积指数及污染负荷指数评价结果显示,黑色页岩发育土壤稀土元素为轻度至中度污染,达到中度生态风险水平. 此外,逐级提取实验结果显示,黑色页岩发育土壤中稀土元素主要以可交换/吸附/碳酸盐结合态（14.4% — 50.8%）、活性有机态（17.7% — 26.2%）及稳定有机质及硫化物结合态（14.6% — 35.2%）的形式存在,其中潜在活性组分占比达64.7%,表现出较高的生物可利用性,应引起重视.     

镉对籽粒苋耐性生理及营养元素吸收积累的影响

初步阐明了镉对籽粒苋耐性生理及营养元素吸收积累的影响,为进一步揭示籽粒苋的镉耐性与镉富集机理奠定了基础。通过对生物量的监测,对叶绿素、蛋白质、游离氨基酸、大量元素及微量元素等的含量的测定,阐明镉胁迫对籽粒苋生长生理、抗胁迫耐性、营养元素吸收分配的影响。研究结果显示,镉胁迫对籽粒苋的生长抑制作用不明显,植株生物量随着镉浓度的提高而轻微降低。随着镉处理浓度的提高,叶绿素含量下降幅度显著;蛋白质和游离氨基酸含量变化幅度不明显;钾含量无大幅变化;镉、磷、钙、镁、锌、铁、锰、铜含量变化幅度较显著。镉、钾、磷、锰的迁移系数随着镉处理浓度的提高无显著变化;钙的迁移系数呈上升趋势;镁、锌、铁、铜的迁移系数均呈下降趋势。这些结果表明：镉胁迫降低籽粒苋叶绿素含量,抑制植株光合作用,继而抑制了植株的生长,但其程度不明显;镉胁迫条件启动活性氧防御机制;引起植株体内部分养分代谢紊乱。结论：低浓度镉处理条件下,籽粒苋受镉离子影响,抗氧化能力下降。在高浓度镉处理条件下,籽粒苋调节了营养元素的吸收和分配,启动了一系列活性氧防御机制,提高了抗胁迫能力。