Instream Bacteria Influences from Bird Habitation of Bridges

The representativeness of ambient water samples collected from bridge crossings has occasionally been challenged because critics contend birds nesting on bridges elevate fecal indicator bacteria concentrations over samples collected from river reaches not spanned by bridges. This study was designed to evaluate the influence, if any, of bridge‐dwelling bird colonies on instream bacteria concentrations. Three bridges in central Texas were sampled under dry‐weather conditions for instream Escherichia coli. Two bridges were inhabited by migratory cliff swallows and one was devoid of birds. Numerous samples were collected from locations upstream, at the upstream bridgeface, and downstream of each bridge to determine whether significant increases in E. coli occurred in a downstream direction when birds were present. E. coli values increased significantly at bridgeface and downstream locations compared to upstream locations throughout the nesting season. During peak bird activity in May, bacteria geometric mean concentrations at bridgeface and downstream locations jumped from background levels <50 to >190 colony forming units (CFU)/100 mL, well above the state geometric mean criterion of 126 CFU/100 mL for primary contact recreation use. Results confirmed that under dry‐weather conditions bird colonies can have a significant impact on bacteria concentrations in the vicinity of the bridges they inhabit and therefore, to avoid this impact, monitoring should occur upstream of bridges.     

RUNOFF NUTRIENT AND FECAL COLIFORM CONTENT FROM CATTLE MANURE APPLICATION TO FESCUE PLOTS1

ABSTRACT: Grazed pastures represent a potential source of non‐point pollution. In comparison to other nonpoint sources (e.g., row‐cropped lands), relatively little information exists regarding possible magnitudes of pollution from grazed pasture; how that pollution is affected by weather, soil, management and other variables; and how the pollution can be minimized. The objective of this study was to assess how the quality of runoff from fescue plots is influenced by duration of cattle manure application (4–12 weeks) and manure application strategy (none, weekly application of 1.4 kg/plot, and monthly application at 5.6 kg/plot). Additional analyses were performed to relate runoff quality to the timing of sample collection. The study was conducted at the University of Kentucky Maine Chance Agricultural Experiment Station north of Lexington. Plots (2.4 m wide by 6.1 m long) were constructed and established in Kentucky 31 fescue (Festuca arundinacea Schreb.) to represent pasture. Grazing was simulated by application of beef cattle manure to the plots. Runoff was generated by applying simulated rainfall approximately 4, S and 12 weeks following initiation of manure application. Runoff samples were collected and analyzed according to standard methods for nitrogen (N), phosphorus (P) and fecal coliforms (FC). Runoff concentrations of N and P from manure‐treated plots were low and generally not consistently different from control plot concentrations or related to manure application strategy. Runoff FC concentrations from manure‐treated plots were higher than from control plot concentrations. Runoff concentrations of ammonia N, total Kjeldahl N, ortho‐P and FC decreased approximately exponentially in response to increasing time of sample collection. These findings suggest that manure deposition on well‐managed pasture at the rates used in this study might have a negligible impact on nutrient content of runoff.     

辽东湾沿岸贝类和环境中的粪大肠菌和细菌总数

对辽东湾沿岸海域几种主要经济贝类体内及其生存环境中的粪大肠菌群和细菌总数进行了调查与研究。结果表明,贝类中粪大肠菌群超标率为53.8%;表层海水中超标率为46.2%;表层沉积物中超标率为12.5%。各种样品中细菌总数的检出结果也表明,该沿岸海域环境和贝类受到了一定的有机污染影响。     

Prairie strips reduce fecal indicator bacteria concentrations in simulated runoff

Vegetative filter strips (VFS) have shown promising results in reducing the downstream transport of many agroecosystem contaminants. A recently developed type of VFS, prairie strips, has been shown to significantly reduce the impact of corn and soybean production systems on water quality in terms of sediment, nitrogen, and phosphorus losses. This study assessed potential additional benefits of prairie strips to include the reduction of pathogens. To assess the impact of prairie strips on manure-laden agricultural runoff, we utilized a physical model of prairie strips in a laboratory flume to conduct highly controlled overland flow experiments. Escherichia coli and Enterococcus concentration reductions of up to 45% and 65% were observed for runoff and infiltration flows, respectively, while mass load reductions of up to 65% were observed for surficial runoff flows. The degree of concentration or mass load reductions was dependent on the residence time of the flow within the strip and the partitioning of overland flow running onto the strip to infiltration and runoff flows. Based on our results and a review of the literature, we developed a design method to provide guidance on the width of prairie strip buffer needed to achieve a user-defined reduction of fecal bacteria concentration.     

二氧化氯和氯复合消毒剂对城市污水的消毒效果

试验研究了二氧化氯和氯复合消毒剂用于经城市污水处理厂处理后的城市污水消毒的效能 ,结果表明 ,二氧化氯和氯复合消毒剂的使用减低了生成的亚氯酸根离子的浓度 ,增加了残余的二氧化氯的浓度 ,粪大肠菌灭活效果良好。     

人类特异性粪厌氧菌基因标记物实时荧光定量PCR检测方法的建立和应用

针对人类粪便污染,选择来源于拟杆菌和双歧杆菌16S rRNA的基因片段作为标记物,分别建立了相应的实时荧光定量PCR检测方法.选取不同来源的粪便样品进行检测,证实了引物的特异性.回收纯化从污水中扩增所得的目标PCR片段,经过连接转化,筛选阳性克隆提取其重组质粒作为实时荧光定量PCR的标准品.通过检测一系列梯度稀释的标准品,确定了拟杆菌基因标记物和双歧杆菌基因标记物定量PCR检测方法分别在1.98×102～1.98×107 copy/μL和2.12×101～2.12×107 copy/μL范围内具有良好的线性关系.     

COLIFORMS AND WATER QUALITY: USE OF DATA IN PROJECT DESIGN AND OPERATION1

ABSTRACT: Knowledge of coliform transport and disappearance may provide information for project design and operation that minimizes potential water quality problems such as the violation of body contact recreation standards. Storm events were sampled in the Caddo River above DeGray Reservoir, Arkansas, and then tracked through the reservoir using the increased turbidity associated with the storm flows. Fecal coliforms were sampled both in the river and throughout the water column in the reservoir. In general, increased fecal coliform concentrations were closely associated with the increased turbidity resulting from the storm flows. This association existed for all three types of turbidity plume movement - overflow, interflow, and underflow. As the turbidity plume moved down the reservoir, fecal coliform concentrations decreased due to die-off, settling, and dilution. With several assumptions, it is possible to use this information to assist in locating recreational sites in a reservoir or to anticipate possible body contact standard violations at existing recreation sites.     

水中粪大肠菌群结果不确定度的评定

依据国家标准和测量不确定度的评定方法,评定水中粪大肠菌群的不确定度.认为不确定度的主要来源为样品保存条件、培养条件、人员操作和判定计数等.通过对地表水和海水样品粪大肠菌群操作过程中的不确定度进行分量计算,建立一种简单的水中粪大肠菌群多管发酵法不确定度评定方法.     

环境孕激素和糖皮质激素的生态毒理效应:进展与展望

孕激素和糖皮质激素的环境行为和生态毒理效应是即环境雌激素和雄激素之后近年来国内外环境激素研究的又一热点课题。由于广泛应用于临床医疗等,这两类物质通过污水处理厂不完全处理和人类农业或畜牧业活动的直接排放从而进入水体环境,进而对生态系统和人类健康产生潜在危害。环境监测数据显示,在地表水中,多种物质存在ng·L-1浓度水平;在污水处理厂进出水中,浓度水平更高,甚至达到数百ng·L-1。孕激素和糖皮质激素类物质主要通过激素受体途径发挥毒性效应,如孕激素受体(PR),糖皮质激素受体(GR)和盐皮质激素受体(MR)。对水生脊椎动物的内分泌系统干扰作用是目前研究的焦点。这两类物质能够影响脑垂体性腺轴转录水平和相应激素合成,影响性腺发育以及导致繁殖能力损伤。这一毒性效应甚至发生在环境浓度水平之下。除此之外,随着组学技术的广泛应用,更多的潜在毒性终点不断被发掘,如对昼夜节律系统和免疫应答的干扰作用。这些研究引导着对环境孕激素和糖皮质激素生态毒理学效应更加深入的理解。     

浙江农村生活污水处理设施水污染物排放标准修订需求分析与建议

以浙江《农村生活污水处理设施水污染物排放标准》(DB33/973—2015)的修订为研究切入点,对比了现行标准与国家和浙江农村生活污水治理的管理要求,分析了浙江农村生活污水处理现状并梳理其他省(自治区、直辖市)标准情况.研究发现DB33/973—2015已不符合浙江实际情况且不能满足浙江对农村生活污水的管理需求,必须开...