镉胁迫对苎麻(Boehmeria nivea)根系及叶片抗氧化系统的影响

镉(Cd)是非必需和毒性最强的重金属元素之一,不合理的开发利用可导致土壤受到Cd的严重污染,严重危及土壤环境或水环境。以苎麻为材料,采用模拟镉(Cd)污染盆栽培养法,选择21 d和49 d等2个不同胁迫期,测定不同浓度Cd2+胁迫下苎麻根系与叶片中渗透调节物质含量、超氧化物岐化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、丙二醛(MDA)含量及根系活力的变化。结果表明,高浓度胁迫49 d后,苎麻根系中的渗透调节物质含量明显高于叶片含量,且极显著高于对照,并在240 mg·L~(-1)Cd处理下出现最高值;胁迫49 d时,根系与叶片的渗透调节物质含量与Cd2+浓度极显著正相关。在2个不同胁迫周期,苎麻根系的SOD与POD活性均明显高于叶片;在胁迫21 d时,根系的CAT活性低于叶片,而胁迫49 d后,则明显高于叶片;胁迫21 d时,苎麻根系与叶片的抗氧化酶活性均较胁迫49 d要高;胁迫49 d时,根系POD活性与Cd2+浓度呈极显著正相关,表明根系POD酶在抗氧化酶中占主导地位。不同胁迫时长下苎麻根系或叶片的MDA含量变化趋势不明显,但根系或叶片受胁迫21 d后的MDA含量随Cd2+浓度增加的波动相对受胁迫49 d后的更明显,表明植物早期生理功能出现暂时性的修复。2个不同胁迫周期内,不同浓度镉胁迫下苎麻的根系活力均比对照组下降。研究显示,苎麻根系与叶片对镉胁迫的应答机制不同,且在不同胁迫时间下的响应机理差异较大,根系表现出更强的耐受能力。     

纳米二氧化硅对两性生殖和孤雌生殖卤虫无节幼体毒性影响的比较研究

研究了纳米二氧化硅(Nano-SiO_2)悬浮液对美国大盐湖两性生殖型卤虫(Artemia francisana,GSL)和渤海湾孤雌生殖型卤虫(Artemia parthenogenetica,BH)无节幼体的急性毒性和抗氧化酶系统的影响。研究结果表明,Nano-SiO_2对GSL和BH无节幼体24 h-LC50分别为23.02 mg·m L~(-1)和20.96 mg·m L~(-1),属低级毒性。Nano-SiO_2降低了GSL和BH无节幼体还原型谷胱甘肽(GSH)含量,抑制了过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性,致丙二醛(MDA)含量升高,表明氧化应激反应是导致Nano-SiO_2对卤虫无节幼体致死的作用机制之一。     

Effects of freshwater leaching on potential bioavailability of heavy metals in tidal flat soils

Environmental Geochemistry and Health - Leaching experiments were conducted to investigate the effects of desalination levels and sediment depths on potential bioavailability of heavy metal (Cd,...     

山东省主要河流中抗生素污染组成及空间分布特征

采用固相萃取-液相色谱/串联质谱法研究了山东省境内四大流域主要河流中抗生素污染组成及空间分布特征,涉及我国用量最大的6类共20种抗生素。结果表明:20种抗生素均有检出,且大环内酯类、喹诺酮类和四环素类抗生素整体检出浓度较高。就流域而言,半岛诸河流域抗生素污染较小,平均总质量浓度61.4 ng/L;海河流域、小清河流域和淮河流域相对较为严重,平均总质量浓度分别为232、175、118 ng/L。抗生素空间分布呈现一定的规律,检出浓度较高的点位主要集中在人口密集区下游,抗生素污染与周边生活污水、养殖企业废水和城市污水处理厂排水密切相关,而且抗生素组成可从一定程度上反映出污染来源。     

Diversity of crude oil-degrading bacteria and alkane hydroxylase (<Emphasis Type="Italic">alkB</Emphasis>) genes from the Qinghai-Tibet Plateau

The aim of this study was to survey the response of the microbial community to crude oil and the diversity of alkane hydroxylase (alkB) genes in soil samples from the Qinghai-Tibet Plateau (QTP). The enrichment cultures and clone libraries were used. Finally, 53 isolates and 94 alkB sequences were obtained from 10 pristine soil samples after enrichment at 10 °C with crude oil as sole carbon source. The isolates fell into the phyla Proteobacteria, Actinobacteria, and Bacteroidetes, with the dominance of Pseudomonas and Acinetobacter. The composition of degraders was different from polar habitats where Acinetobacter sp. is not a predominant responder of alkane degradative microbial communities. Phylogenetic analysis showed that the alkB genes from isolates and enrichment communities formed eight clusters and mainly related with alkB genes of Pseudomonas, Rhodococcus, and Acinetobacter. The alkB gene diversity in the QTP was lower than marine environments and polar soil samples. In particular, a total of 10 isolates exhibiting vigorous growth with crude oil could detect no crude oil degradation-related gene sequences, such as alkB, P450, almA, ndoB, and xylE genes. The Shannon-Wiener index of the alkB clone libraries from the QTP ranged from 1.00 to 2.24 which is similar with polar pristine soil samples but lower than that of contaminated soils. These results indicated that the Pseudomonas, Acinetobacter, and Rhodococcus genera are the candidate for in situ bioremediation, and the environment of QTP may be still relatively uncontaminated by crude oil.     

Histopathological changes in zebrafish embryos exposed to DLPCBs extract from Zhanjiang coastal sediment

Dioxin-like polychlorinated biphenyls (DLPCBs) are ubiquitous persistent pollutants that cause adverse effects in many environmental organisms. DLPCBs in marine sediments can be absorbed by benthic organisms, bioaccumulate, and biomagnify through the food chain and threaten animal and human health. There are no reports of DLPCBs concentrations in the Zhanjiang Gulf seabed. This study was designed to investigate the concentration of DLPCBs in the Zhanjiang coastal sediment and histopathological changes in zebrafish (Diano rerio) embryos exposed to environmentally relevant concentrations of DLPCBs. Of the five sites selected, two sites TS and JSW contained DLPCBs at concentrations of 0.08 and 22.54 ng/g dry sediment, respectively. Two groups of zebrafish embryos were used. One group was exposed to 3.75, 7.5, 15, 30, and 60 mg/ml of DLPCBs extracted from the sediments sampled from the TS site and the second group to 4.375, 8.75, 17.5, 35, and 70 mg/ml of DLPCBs from JSW site from 0.75 h post-fertilization (hpf) to 96 hpf. The zebrafish exposed to 60 and 70 mg/ml of DLPCBs at 96 hpf displayed gross histopathological changes with cardiac lesions including pericardial edema being the most deleterious. Other changes observed were hydropic degeneration of gill filaments and hepatocytes, loss of intestinal folds, and uninflated swim bladder. It appears that only a few sites of the Zhanjiang gulf are contaminated with DLPCBs. This is the first report of histopathological changes in the gills, hepatocytes, intestines, heart, and the swim bladder in zebrafish embryos exposed to DLPCBs from a coastal sediment. Further studies with sampling at different stages of development are required to identify which organ/tissue is most sensitive to DLPCBs.     

Quality assessment of groundwater from the south-eastern Arabian Peninsula

Assessment of groundwater quality plays a significant role in the utilization of the scarce water resources globally and especially in arid regions. The increasing abstraction together with man-made contamination and seawater intrusion have strongly affected groundwater quality in the Arabia Peninsula, exemplified by the investigation given here from the United Arab Emirates, where the groundwater is seldom reviewed and assessed. In the aim of assessing current groundwater quality, we here present a comparison of chemical data linked to aquifers types. The results reveal that most of the investigated groundwater is not suitable for drinking, household, and agricultural purposes following the WHO permissible limits. Aquifer composition and climate have vital control on the water quality, with the carbonate aquifers contain the least potable water compared to the ophiolites and Quaternary clastics. Seawater intrusion along coastal regions has deteriorated the water quality and the phenomenon may become more intensive with future warming climate and rising sea level.     

SR系统工艺设计的几个必备要素：石屏县城市污水土地处理工程例析

在ＳＲ污水土地处理系统工艺设计中，处理场地的环境特征、限制性设计参数、作物选型及预处理方式的选择等决定了该系统运动的成败，应合理分析各必备要素以指导设计中参数的选择，达到污水处理与资源化的有机结合。     

底泥疏挖工程对草海水生生态环境的影响预测

草海底泥疏挖工程的实施，必将对草海水生生态环境产生影响，预测结果表明，疏挖后草海水质有所改善，基本达到国家地面水Ｄ类标准，但相当长时间内仍疳保持富营养化状态，生态系统短期内改善不大，需较长时间，依靠人工强化恢复和自然恢复。草海水生生态系统方能逐步恢复。     

不同评价指数模式对评价结论的影响

算术平均法、几何平均法及Ｎｅｍｅｒｏｗ法可直观、方便地反映各污染物平均污染水平，但体现个别超标污染物的环境影响有欠缺。组合指数模式将超示和未超标两部分进行互无运算关系的组合，在评价污染物，特别是多污染物对区域环境的污染对及人体健康的影响上，具有环境卫生学及环境毒理学意义。