粪大肠菌群快速测定——纸片法的应用

采集苏州具有代表性的地表水水体22个点位的样品,进行粪大肠菌群的测定方法比较,结果表明,《粪大肠菌群快速测定--纸片法》适于测定受粪便污染程度较轻的湖泊水体.但是,该方法的培养时间对阳性管率有明显影响,认为16 h～18 h是比较理想的培养时间.     

海南红沙港海水中细菌污染调查与评价

于2006年4-6月在红沙港海域进行了四个航次调查,对海域中5个站位的海水样品进行了细菌学检测.结果表明,四个航次海水粪大肠杆菌群超标率最高为40%,异养细菌总数超标率均达60%以上.四个航次海水粪大肠杆菌单项污染指数平均值分别为0.755、1.792、2.215和0.578,异养细菌总数单项污染指数平均值分别为1.54、2.73、24.04和6.11.生物统计学分析显示,粪大肠杆菌群与异养细菌总数存在一定的正相关关系,其相关系数r2=0.439 9.红沙港海水已受到粪大肠杆菌和异氧细菌污染.     

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...     

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。     

Evidential role of municipal solid waste and liquid effluent on environment and public health

Cities in Bangladesh produce large amounts of solid waste (SW) through various human activities which severely pollutes our native environment. As a result, SW pollutes the three basic environmental elements (air, water, and soil) by increasing pathogenic microbial load, which might be hazardous to public health directly or indirectly. In this study, we conducted 30 samples (i.e., soil, water, and air) collected from areas where municipal solid wastes are dumped (Tangail Sadar Upazila, Bangladesh). All the samples were analyzed to assess bacteriological quality for presumptive viable and coliform count using different agar media. We performed serial dilution 10⁻³–10⁻¹⁰ times for soil and water samples, and the diluted samples were spread on Mac-Conkey agar and nutrient agar plates. For the air sample, the sterile media containing petri-dish was placed adjacent to the dumpsite of the municipal waste and kept for an hour. Then all the samples were incubated at 37°C overnight for total viable count (TVC) and total coliform count (TCC). Biochemical tests and PCR were performed for the identification of these microorganisms. The antibiogram study was performed to reveal their (identified bacteria) susceptibility against clinically used antibiotics according to the standard disk diffusion technique. The highest bacterial loads were found in the air: TVC 3.273 × 10³ and TCC 1.059 × 10³ CFU/plate; tube-well water: TVC 8.609 × 10³, and TCC 8.317 × 10³ CFU/mL; in surface water: TVC 6.24 × 10¹³ CFU/mL and TCC 2.2 × 10¹² CFU/mL; in soil: TVC 2.88 × 10¹¹ and TCC 1.02 × 10¹¹ CFU/g, respectively. Microbes from SW can be transmitted through air, dust particles, or flies, and here we found an average of 1120 microbes spread over 63.61 cm² area per hour. Eight bacterial isolates (Pseudomonas spp., Klebsiella spp., E. coli, Proteus spp., V. cholera, Salmonella spp., Shigella spp., and Vibrio spp.) were identified by the biochemical test. Among them, E. coli and Shigella spp. were further ensured by PCR targeting bfpA and ipaH genes. Antibiotic susceptibility test results showed that E. coli isolates were highly resistant to erythromycin (80%); Shigella spp. were resistant to nalidixic acid (90%), whereas Salmonella spp. was found resistant to kanamycin (90%). Vibrio spp. were also resistant to azithromycin (80%) and erythromycin (80%), which should be a great concern for us. A semi-structured survey revealed that 63% of respondents suffered from different clinical conditions (intestinal diseases) due to SW pollution. So, steps should be taken to improve the proper management and disposal of solid waste and liquid effluent to save our environment and public health.     

Potential health hazard of drinking water in restaurants and tea stalls

Potable and equitable drinking water (DW) is a fundamental human right and essential for human health. This study is conducted to assess the groundwater and jar water quality of the roadside restaurants and tea stalls used for drinking by the local people around the Gazipur City area in Bangladesh. Water samples from 173 restaurants and tea stalls are collected. The physico-chemical and biological parameters are analyzed according to the guidelines and standards. The results illustrate that the color, EC, and Mn of 41%, 80%, and 62% of the samples, respectively, exceed the WHO and Environmental Conservation Rules (ECR) standards. In addition, E. coli and total coliform exceeding the threshold standards are found in 47% and 64% of the water samples, respectively. The contamination of DW by fecal coliforms is confirmed and supported by prior studies, which indicates that the DW supplied in restaurants and tea stalls are unsafe because of the possible presence of pathogens. These may cause potential health hazards to consumers from various water-borne diseases. Poor sanitation, unhygienic practices, and improper disposal of wastewater are responsible for the microbial contamination of DW. So, the authorities in charge of these places should take the right regulatory steps, such as regular sanitation inspections, DW quality monitoring, hand-washing practices, and better sanitation in these places.     

Modeling manure-borne bromide and fecal coliform transport with runoff and infiltration at a hillslope

Hillslope vegetated buffers are recommended to prevent water pollution from agricultural runoff. However, models to predict the efficacy of different grass buffer designs are lacking. The objective of this work was to develop and test a mechanistic model of coupled surface and subsurface flow and transport of bacteria and a conservative tracer on hillslopes. The testing should indicate what level of complexity and observation density might be needed to capture essential processes in the model. We combined the three-dimensional FEMWATER model of saturated-unsaturated subsurface flow with the Saint-Venant model for runoff. The model was tested with data on rainfall-induced fecal coliforms (FC) and bromide (Br) transport from manure applied at vegetated and bare 6-m long plots. The calibration of water retention parameters was unnecessary, and the same manure release parameters could be used both for simulations of Br and FC. Surface straining rates were similar for Br and bacteria. Simulations of Br and FC concentrations were least successful for the funnels closest to the source. This could be related to the finger-like flow of the manure from the strip along the bare slopes, to the transport of Br and FC with manure colloids that became strained at the grass slope, and to the presence of micro-ponds at the grassed slope. The two-dimensional model abstraction of the actual 3D transport worked well for flux-averaged concentrations. The model developed in this work is suitable to simulate surface and subsurface transport of agricultural contaminants on hillslopes and to evaluate efficiency of grass strip buffers, especially when lateral subsurface flow is important.     

Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters1

Sejkora, Patrick, Mary Jo Kirisits, and Michael Barrett, 2011. Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters. Journal of the American Water Resources Association (JAWRA) 47(6):1275–1284. DOI: 10.1111/j.1752‐1688.2011.00566.x Abstract: Animals, such as birds, are a source of fecal indicator bacteria and pathogens in the environment. Our objective was to determine whether a colony of cliff swallows nesting underneath a bridge would yield a measurable increase in fecal indicator bacteria (specifically Escherichia coli) in the underlying creek. When the swallows were absent, dry‐weather concentrations of E. coli upstream and downstream of the bridge (in Austin, Texas) were below the Texas contact recreation criteria. When the swallows were present, dry‐weather geometric‐mean E. coli concentrations increased significantly from upstream (43 most probable number [MPN]/100 ml) to downstream (106 MPN/100 ml) of the bridge. One exceedance and one near‐exceedance of the Texas single‐sample contact recreation criterion were observed during the swallows’ nesting phase. When the swallows were present, the downstream E. coli geometric‐mean concentration in storm events (875 MPN/100 ml) was significantly higher than the upstream concentration (356 MPN/100 ml), suggesting that runoff flushes swallow feces from the ground into the creek. Although the loading of E. coli from cliff swallows nesting under bridges can be significant (e.g., dry‐weather loading of 3.1 × 10⁸ MPN/day/nest), the zoonotic potential of the cliff swallow must be examined to determine the risk to human health from contact recreation in waters contaminated with cliff swallow feces.     

A long-term study comparing membrane filtration with Colilert defined substrates in detecting fecal coliforms and Escherichia coli in natural waters

Assessment methods for determining the presence and number of fecal bacteria and Escherichia coli (E. coli) in waters, foodstuffs, sewage effluent, and soils have evolved from multiple tube fermentations (MTF's) to membrane filtrations (MF's) to, most recently, defined substrate technologies (DST's). Mounting evidence indicates Colilert DST (IDEXX, Westbrook, ME) to be a versatile assessment technique for detecting and enumerating E. coli over a range of applications. This study compared the performance of Colilert DST with a confirmed standard MF technique using m-FC broth (Millipore, Bedford, MA) in assessing E. coli in ten different environmental water samples obtained monthly over a 3-year period from the upper Appomattox River, VA. For the duration of the study, E. coli counts measured by Colilert DST were positively correlated (Pearson's correlation coefficient=0.956; slope=0.979; p<0.0001) with E. coli counts measured by confirmed MF procedures. The results of a two-factor ANOVA revealed that Colilert DST counts compared equally to confirmed MF counts by year (p=0.974), by stream sampled (p=1.0), and by season (p=0.696). E. coli counts were significantly lower during cold season months (Dec/Jan/Feb) than during warm season months (Jun/Jul/Aug) for each year contributing to marked variation in sample quality. Counts obtained by Colilert DST compared equally to those obtained by MF across all samples and dates for the three years. Colilert DST presents a laboratory protocol that is simpler to manage, quicker to process, and easier to quantify results than MF. These factors, plus the enhanced precision and versatility of Colilert DST over the span of this three-year study attests to its suitability for testing ambient surface waters.