Distribution of quinolone and macrolide resistance genes and their co-occurrence with heavy metal resistance genes in vegetable soils with long-term application of manure

The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.

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有机化合物水解的研究方法

有机化合物在水中的化学降解是其在环境中消失的重要途径之一，本文介绍有机化合物在水中的化学降解的研究方法，并给出研究实例。     

广西涠洲岛沉凝灰岩土壤粘粒矿物的研究

用X射线衍射分析和电子显微镜分析,对涠洲岛沉凝灰岩母质发育土壤的两个典型剖面八个土样的粘粒矿物进行分析研究。结果表明,离火山口距离不同的两个剖面土壤粘粒矿物组成不同,1号剖面以2:1型粘粒矿物为主,2号剖面则以1:1型粘粒矿物为主;结合其它分析结果,讨论了两个剖面土壤粘粒矿物组成不同的原因、对土壤有关特性的影响及其与土壤形成和分类的关系。     

农药和其它有机化合物环境参数的相关性及其预测

农药和其它有机化合物的水溶解度、正辛醇／水分配系数、有机碳吸附常数和生物浓缩因子等物化参数之间存在着明显的相关性，有机化合物的水溶解度与其正辛醇／水分配系数、有机碳吸附常数和生物浓缩因子呈负相关；正辛醇／水分配系数与有机碳吸附常数和生物浓缩因子呈正相关。本文所建立的数学关系式能较好地预测未知化合物的环境特性。     

负载型金催化剂用于室温下CO的消除

从催化活性、抗潮湿、抗硫中毒、稳定性等方面考察了负载型金催化剂对于ＣＯ氧化反应的性能。筛选出的２－３催化剂可在－２２℃下完全消除ＣＯ，并且在催化活性、抗潮湿、抗硫中毒、稳定性等方面具有现行催化剂无法比拟的优点。     

Persistent organic pollutants in water and surface sediments of Taihu Lake,China and risk assessment

Organic pollutants, especially persistent organic pollutants were examined in the water and surface sediments of Taihu Lake, China. Both 12 water and 12 sediment samples were collected over the lake. C-18 solid-phase extraction technique was applied to extract organic pollutants in collected water samples. Soxhlet extraction procedure was used to extract organic pollutants in sediment samples. The analysis was performed by GC-MS controlled by a Hewlett Packard chemstation. Two hundred and seventy-three kinds of organic chemicals in water were examined, 200 more than that detected in 1985; 188 kinds of chemicals in sediments were detected as well. Among them 21 kinds of chemicals belong to priority pollutants as well as 17 kinds to be the endocrine disruptors. The concentrations of the pollutants were more than 2 times higher than that in 1985. The possible source and relation to anthropogenic activity were discussed.     

Cd对不同形态漆酶修复DDT污染土壤的影响

研究了重金属Cd对游离漆酶和同定化反胶团漆酶修复土壤有机氯农药DDT污染的影响.结果表明.游离漆酶对土壤中DDT各组分均有不同程度降解,且均随着cd浓度的增大而降低,含量越高的组分降解率越高.受到Cd污染的影响也越大(P,P'-DDT>P,P'-DDD>0.P'-DDT>P,P'-DDE);当Cd浓度分别为0、0.5、1和2 mg·kg-1时,游离漆酶对土壤中DDT总量的降解率分别为50.68%、32.50%、14.92%和13.40%.固定化反胶团漆酶比游离漆酶能更有效地降解DDT,DDT降解率在无Cd和有Cd存在时(Cd浓度为0.5 mg·kg-1)分别提高20%和30%左右.     

探讨“烟塔合一”技术在环评中大气环境的防护距离

归纳"烟塔合一"项目评估的共性要求,在分析德国模式不能充分反映特定条件下对近距离保护目标影响的基础上,阐明了环境防护距离设置的必要性,并就目前所采取环境防护距离计算方法及部分项目风洞试验结果进行解析,提出相关建议。     

Regional crop yield, water consumption and water use efficiency and their responses to climate change in the North China Plain

The North China Plain (NCP) is one of the most important regions for food production in China, with its agricultural system being significantly affected by the undergoing climate change and vulnerable with water stress. In this study, the Vegetation Interface Processes (VIP) model is used to evaluate crop yield, water consumption (ET), and water use efficiency (WUE) of a winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) double cropping system in the NCP from 1951 to 2006. Their responses to future climate scenarios of 21st century projected by the GCM (HadCM3) with Intergovernmental Panel on Climate Change Special Report on Emission Scenario (IPCC SRES) A2 and B1 emissions are investigated. The results show a rapid enhancement of crop yield in the past 56 years, accompanying with slight increment of ET and noticeable improvement of WUE. There exist spatial patterns of crop yield stemmed mainly from soil quality and irrigation facilities. For climate change impacts, it is found that winter wheat yield will significantly increase with the maximum increment in A2 occurring in 2070s with a value of 19%, whereas the maximum in B1 being 13% in 2060s. Its ET is slightly intensified, which is less than 6%, under both A2 and B1 scenarios, giving rise to the improvement of WUE by 10% and 7% under A2 and B1 scenarios, respectively. Comparatively, summer maize yield will gently decline by 15% for A2 and 12% for B1 scenario, respectively. Its ET is obviously increasing since 2050s with over 10% relative change, leading to a lower WUE with more than 25% relative change under both scenarios in 2090s. Therefore, possible adaptation countermeasures should be developed to mitigate the negative effects of climate change for the sustainable development of agro-ecosystems in the NCP.     

化学链燃烧中钙基载氧体CaS04再生的氧化反应机理

在热重和红外联用进行等温实验的基础上,探讨了氧体积分数为10%、20%,970-1150℃温度范围内化学链燃烧过程中钙基载氧体再生(cas)的氧化特性-结果显示,CaS氧化的直接产物主要为CaSO4,只有在诱导期生成极少量CaO和SO2;但CaSO4与CaS还可进一步反应,生成更多Can和S02.通过对氧气浓度和温度的实验条件改变,研究了CaS04的转化率、转化速率,并辅以S02析出速率分析,获得了CaSO4相对于CaO的瞬时选择性、Ca.SO4的收率和反应选择率.结果表明,钙基载氧体CaSO.再生过程氧化反应的适宜条件为温度970-1000℃以及较高的氧气气氛.这不仅可以抑制S02的排放量从而得到较高的反应选择率.同时反应过程也具有较高的转化速率.