Fate of antimicrobial resistance genes in response to application of poultry and swine manure in simulated manure-soil microcosms and manure-pond microcosms

This study aimed to determine the occurrence, abundance, and fate of nine important antimicrobial resistance genes (ARGs) (sul1, sul2, tetB, tetM, ermB, ermF, fexA, cfr, and Intl1) in the simulated soil and pond microcosms following poultry and swine manure application. Absolute quantitative PCR method was used to determine the gene copies. The results were modeled as a logarithmic regression (N?=?mlnt?+?b) to explore the fate of target genes. Genes sul1, Intl1, sul2, and tetM had the highest abundance following the application of the two manure types. The logarithmic regression model fitted the results well (R ² values up to 0.99). The reduction rate of all genes (except for the genes fexA and cfr) in manure-pond microcosms was faster than those in manure-soil microcosms. Importantly, sul1, intl1, sul2, and tetM had the lowest reduction rates in all the samples and the low reduction rates of tetM was the first time to be reported. These results indicated that ARG management should focus on using technologies for the ARG elimination before the manure applications rather than waiting for subsequent attenuation in soil or water, particularly the ARGs (such as sul1, intl1, sul2, and tetM investigated in this study) that had high abundance and low reduction rate in the soil and water after application of manure.     

全球升温1.5℃与2.0℃情景下长江中下游地区极端降水的变化特征

基于长江中下游地区1961~2100年区域气候模式COSMO-CLM(CCLM)模拟与1961~2005年气象站观测的逐日降水数据,通过统计计算年降水量、强降水量、暴雨日数和极端降水贡献率4个极端降水指数,研究全球升温1.5℃与2.0℃情景下,长江中下游地区极端降水的时空变化特征。结果表明:(1)全球升温1.5℃情景下,年降水量相对于1986~2005年减少5%,强降水量、暴雨日数和极端降水贡献率分别增加7%、33%和4%;概率密度曲线表明,年降水量均值下降,强降水量、暴雨日数和极端降水贡献率均值上升,极端降水方差增大;年降水量、强降水量和暴雨日数在空间上表现为南部增加北部减少,极端降水贡献率则相反。(2)全球升温2.0℃情景下,年降水量下降3%,强降水量、暴雨日数和极端降水贡献率分别上升15%、46%和15%;年降水量均值稍有减少且方差稍有上升,强降水量、暴雨日数和极端降水贡献率均值和方差明显增加;年降水量减少区域位于长江主干以北,强降水量、暴雨日数和极端降水贡献率表现为绝大部分地区增加的空间变化特征。(3)全球升温由1.5℃至2.0℃时,年降水量、强降水量、暴雨日数和极端降水贡献率分别增加3%、7%、10%和11%;随升温幅度的增加极端降水均值和方差上升;极端降水呈增加态势的范围扩大。因此,努力将升温控制在1.5℃对降低极端降水的影响具有重要意义。     

Levels and distribution of Dechloranes in sediments of Lake Taihu,China

The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g^?1 dw and 0.051 to 2.10 ng g^?1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake.     

Bio-immobilization of Cu and Zn in recirculated bioreactor landfill

Purpose  

To protect the environmental quality of soil, groundwater, and surface water near the landfill site, it is necessary to make an accurate assessment of the heavy metal mobility. This study aims to present the bio-immobilization behavior of heavy metals in landfill and provide some reference suggestion for the manipulation of heavy metal pollution control after closure.     

CEMS烟气在线连续监测系统常见问题的探讨

简述CEMS的工作原理,提出CEMS工作中的常见问题,阐述常见问题的现象,剖析常见问题原因,并针对性的提出了应对措施。     

Pseudomonas sp.fz胞外分离物降解四溴双酚A

四溴双酚A(TBBPA)是全球消耗量最大的溴系阻燃剂。通过活性物质的定位、分离和TBBPA产物的分析等步骤,对Pseudomonas sp.fz胞外分离物降解TBBPA进行了研究。结果表明,存在于胞外的活性物质通过异丙基断裂和脱溴两条途径降解TBBPA。通过超滤,Sephadex G-10分离纯化得到了具有降解活性的小分子物质,分子量约为376~456 Da,初步鉴定为短肽类物质。这种小分子物质具有很好的热稳定性(30~80℃),在弱酸性条件下(2.0~5.0)活性较高,其活性还受金属离子、氧气和抑制剂(Na N3)的影响。此外,部分纯化的小分子物质在一定条件下能够产生羟基自由基(·OH)。     

Organochlorine pesticides in soil profiles from Tianjin, China

Soil cores were collected from soils at five sites in Tianjin area for the determination of hexachlorocyclohexane isomers (HCHs, including alpha-HCH, beta-HCH, gamma-HCH and delta-HCH), dichlorodiphenyltrichloroethane and metabolites (DDXs, including p,p'-DDT, p,p'-DDE and p,p'-DDD) and total organic carbon (TOC). The levels and vertical distributions of HCHs and DDXs are studied. Results show that the application of pesticides in the past years was the major contributor of HCHs and DDXs accumulation in the sampling areas. Significant positive correlations were seen between the residual and application amounts of HCHs and DDXs. Wastewater irrigation did not bring a significant contribution of HCHs or DDXs into the soils. HCHs and DDXs concentrations peak at the surface and decline in soil profile with depth, while fluctuations were observed in the plow layers of some cultivated soils caused by frequent cultivation activities and batch irrigation. Positive correlations were observed between the contents of TOC and HCHs and DDTs. Although the amounts of HCHs application in all sampling sites are larger than DDXs, at surface and near surface layers of most sampling sites, the concentrations of summation operatorHCHs are lower than summation operatorDDXs. The composition of DDXs in the applied pesticides and sampled soils indicates that there is no recent DDT input at the sample areas.     

宁波-舟山海域入海污染物环境容量研究

在宁波-舟山海域数值模拟潮流场的基础上,建立了该海域各污染源的响应系数场,计算了主要污染源COD、无机氮和活性磷酸盐的分担率场,及各污染源和控制单元的环境容量.研究结果将为该海域入海污染物总量控制提供科学依据.     

前处理-水解-生物接触氧化工艺处理染料废水

介绍了前处理-水解-生物接触氧化工艺处理染料废水的工程实例.当进水COD≤8000 mg/L时,出水可达到国家〈污水综合排放标准〉（GB8978-1996）二级标准.     

新型沸石填料间歇硝化反应器的研究

介绍一种新型沸石填料 ,用于提高生物脱氮系统中硝化反应器的硝化性能。试验结果表明 ,应用了沸石填料的硝化反应器的硝化性能得到了显著提高 ,在脱氮效率和速率上 ,与普通生物载体硝化反应器相比具有明显的优势。硝化反应器连续运行 17d ,出水氨氮基本在 1mg/L以下 ,氨氮去除率在 97%以上。该系统停止运行 5 0d后再次启动 ,一周内硝化性能得以恢复