Enhanced bio-decolorization of 1-amino-4-bromoanthraquinone-2-sulfonic acid by Sphingomonas xenophaga with nutrient amendment

Bacterial decolorization of anthraquinone dye intermediates is a slow process under aerobic conditions. To speed up the process, in the present study, effects of various nutrients on 1-amino-4-bromoanthraquinone-2-sulfonic acid (ABAS) decolorization by Sphingomonas xenophaga QYY were investigated. The results showed that peptone, yeast extract and casamino acid amendments promoted ABAS bio-decolorization. In particular, the addition of peptone and casamino acids could improve the decolorization activity of strain QYY. Further experiments showed that L-proline had a more significant accelerating effect on ABAS decolorization compared with other amino acids. L-Proline not only supported cell growth, but also significantly increased the decolorization activity of strain QYY. Membrane proteins of strain QYY exhibited ABAS decolorization activities in the presence of L-proline or reduced nicotinamide adenine dinucleotide, while this behavior was not observed in the presence of other amino acids. Moreover, the positive correlation between L-proline concentration and the decolorization activity of membrane proteins was observed, indicating that L-proline plays an important role in ABAS decolorization. The above findings provide us not only a novel insight into bacterial ABAS decolorization, but also an L-proline-supplemented bioaugmentation strategy for enhancing ABAS bio-decolorization.     

基于CI指数的祁东县干旱特征分析

利用衡阳市祁东县气象站1960~2013年逐日平均气温、降水观测数据,计算综合气象干旱指数。以国家标准《气象干旱等级GB/T20481~2006》为依据划分不同干旱等级、计算干旱日数、干旱强度等,在此基础上统计干旱日的年、年代际统计并作了线性分析,并为应对干旱提出了自己的建议:祁东县干旱日每年均有出现,但不同强度干旱日发生频率不同,在全球变暖大背景下,干旱日等级越高,其增幅愈明显;祁东县的平均干旱过程数为2.5次/a,一年出现2次干旱过程几率最大,无旱过程的几率为9.3%;在统计年干旱强度时,选用持续时间最长的一次有较好代表性。近54a来,干旱强度年变化可分为三高两低,目前处于干旱强度较高期;祁东县大部分年份有季节性干旱,单季旱以秋旱为主,在双季干旱中,夏秋连旱居多,历史上夏秋冬连旱出现了三次;为了应对日趋严重的干旱,需增强人们的防旱抗灾意识、加大水利设置投入、推广节水农业和提高干旱监测预警能力。     

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.     

Chemical characterization and source identification of PM2.5 in Luoyang after the clean air actions

Luoyang is a typical heavy industrial city in China, with a coal-dominated energy structure and serious air pollution. Following the implementation of the clean air actions, the physicochemical characteristics and sources of PM_2.5 have changed. A comprehensive study of PM_2.5 was conducted from October 16, 2019 to January 23, 2020 to evaluate the effectiveness of previous control measures and further to provide theory basis for more effective policies in the future. Results showed that the aerosol pollution in Luoyang in autumn and winter is still serious with the average concentration of 91.1 μg/m³, although a large reduction (46.9%) since 2014. With the contribution of nitrate increased from 12.5% to 25.1% and sulfate decreased from 16.7% to 11.2%, aerosol pollution has changed from sulfate-dominate to nitrate-dominate. High NO₃⁻/SO₄²⁻ ratio and the increasing of NO₃⁻/SO₄²⁻ ratio with the aggravation of pollution indicating vehicle exhaust playing an increasingly important role in PM_2.5 pollution in Luoyang, especially in the haze processes. Secondary inorganic ions contributed significantly to the enhancement of PM_2.5 during the pollution period. The high value of Cl⁻/Na⁺ and EC concentration indicate coal combustion in Luoyang is still serious. The top three contributor sources were secondary inorganic aerosols (33.3%), coal combustion (13.6%), and industrial emissions (13.4%). Close-range transport from the western and northeastern directions were more important factors in air pollution in Luoyang during the sampling period. It is necessary to strengthen the control of coal combustion and reduce vehicle emissions in future policies.     

汶川地震映秀镇地质条件与地表破裂特征调查

2008年5月12日14时28分04秒,四川省汶川县发生了MS 8.0地震.根据地震部门测定,本次地震是从映秀开始破裂,震中位于四川汶川县映秀镇附近(北纬31.015°,东经103.365°).在中国地震局组织的汶川地震科学考察成果基础上,本文分析了映秀地质条件:主要发育的地层为二叠系的石英闪长岩,震旦系的砂岩;通过研究区的主要构造为龙门山中央断裂-映秀-北川断裂;主要的地貌类型为河流地貌.调查了研究区的地表破裂特征,根据研究区的地貌类型将其划分为A、B、C三段,A段为河床沉积地貌,垂直断距最大;B段为丘陵地貌,断距中等,但诱发崩塌地质灾害;C段为河流边滩地貌,断距较小,但震害严重.     

Sulfate-enhanced degradation of Rhodamine B in the hydrogen peroxide/hydroxylamine system

Environmental Chemistry Letters - Hydroxyl radicals are commonly produced either by metal activation or by using external energy. However, the application of these methods is limited by low working...     

刈割对香港草地干物质生产的影响

研究了刈割频率对香港草地于物质生产的影响。结果表明，刈割使干物质生产量下降，刈割频率越高生产量下降越大。禾本科植物受刈割影响比木本和非禾本科草本植物大，且停止刚割一年后生物量仍低于对照点。认为常年刈割是华南草地生产力下降的重要原因之一。     

大气苯酚对蚕桑污染毒性

本文以桑树和家蚕为试验生物，采用静态模拟熏气和自然污染调查相结合的方法，对大气苯酚污染蚕桑引起家蚕生长发育障碍进行了观察、分析，认为大气苯酚以间歇性较高浓度侵入蚕室时，会直接致蚕中毒；大气中苯酚以持续较低浓度作用时桑叶内会累积苯酚，间接对象蚕有毒害。家蚕受害后，轻则表现力食欲不振，群体发育不齐，体色灰暗、体重减轻、主要经济性状下降，重则死亡。，Ｆ＿（０．０１）＝２．８０说明因熏气处理次数引起盛食蚕体重变化的差异极显著，也即较高浓度的苯酚气会直接危害家蚕生长、发育。综上所述，在有关工厂附近大气内苯酚浓度虽然不是很高，也没有被正式列入监测范围，因此也没有监测指标。但此浓度下桑叶内会累积苯酚，家蚕食叶则会间接遭受其危害；如急性排放的苯酚气侵入蚕室，则会对家蚕直接致害，造成经济性状下降，甚至死亡。苯酚是有机毒物，食品上禁用早有规定，如何防止大气苯酚在生态系统中积累、迁移，保障陆地生物包括人类免受其毒害，是值得引起重视的环境问题。     

天津地区表层土中饱和烃的组成与分布特征

为揭示天津地区不同环境功能区表层土壤中饱和烃污染特征及其来源,分析了该地区几个具代表性的环境功能区表层土(0～25cm)中饱和烃化合物的组成和分布特征,重点讨论了正构烷烃和甾、萜烷烃类化合物的组成、分布及环境意义,比较了不同层次(亚层)(0～5cm,5～10cm,10～15cm,15～20cm,20～25cm)中这些化合物及相关的地球化学参数的变化规律。结果表明,不同采样点以及同一采样点的不同亚层之间正构烷烃的组成特征存在不同程度的差别,而甾、萜烷烃类化合物组成与分布特征均较为接近。正构烷烃以及甾、萜类地球化学参数综合分析揭示,不同采样点之间正构烷烃的来源多样,中低分子量的正构烷烃主要来源于石油等化石燃料,高分子量正构烷烃主要来源于高等植物蜡的分解产物,但甾、萜烷烃类化合物的来源是一致的,且主要来源于石油烃污染。不同采样点表层土中饱和烃的来源及污染程度均存在一定的差别,市区、油田附近、经济开发区以及近郊区受石油源影响较重,北部山区污染较轻,且主要来源于高等植物的降解。除个别采样点外,同一采样点不同亚层之间饱和烃的组成特征基本一致,表明污染源是一致的,主要来源由表层污染物往下迁移所致。