Comparison of two methods for detection of fecal indicator bacteria used in water quality monitoring of the Three Gorges Reservoir

Scientifically sound methods to rapidly measure fecal indicator bacteria are important to ensure safe water for drinking and recreational purposes.A total of 200 water samples obtained from the Three Gorges Reservoir during three successive one-year study periods(October 2009 to September 2012) were analyzed using multiple-tube fermentation(MTF)and most probable numbers combined with polymerase chain reaction(MPN–PCR).The MPN–PCR method was found to be significantly more sensitive than the MTF method for detecting Escherichia coli and Enterococcus spp.,and of equal sensitivity for detecting total coliforms when all surface water samples were grouped together.The two analytical methods had a strong,significant relationship,but MPN–PCR took only 12–18 hr,compared with the 3–8 days needed using the MTF method.Bacterial concentrations varied per sampling site but were significantly lower in the mainstream of the Yangtze River than those in the backwater areas of tributaries.The water quality of 85.8% of water samples from the mainstream was suitable for use as a centralized potable water source,while the water quality of 52.5% of water samples from the backwater areas was unsuitable for recreational activities.Relationships between fecal indicator bacteria showed significant correlation(r = 0.636–0.909,p 0.01,n = 200),while a weak but significant correlation was found between fecal indicators and water turbidity,water temperature,daily inflow,and total dissolved solids(r = 0.237–0.532,p 0.05,n = 200).The study indicated that MPN–PCR is a rapid and easily performed deoxyribonucleic acid(DNA)-based method for quantitative detection of viable total coliforms,E.coli,and Enterococcus spp.in surface water.     

粪大肠菌群酶底物法在环境应急监测中的应用

结合国外粪大肠菌群的酶底物检测方法，针对某次突发环境污染事件，用酶底物法和标准方法多管发酵法同步检测受污染地表水中的粪大肠菌群，讨论酶底物法在应急监测中检测粪大肠菌群的适用性。结果表明，两种方法的测定数据显著相关，没有统计学差异（ P＞0．05）。相对于多管发酵法，酶底物法特异性强，检测时间短，二次污染少，符合应急监测的要求。     

Temporal genetic variability and host sources of Escherichia coli associated with fecal pollution from domesticated animals in the shellfish culture environment of Xiangshan Bay, East China Sea

This study was conducted to analyze the genetic variability of Escherichia coli from domesticated animal wastes for microbial source tracking (MST) application in fecal contaminated shellfish growing waters of Xiangshan Bay, East China Sea. (GTG)₅ primer was used to generate 1363 fingerprints from E. coli isolated from feces of known 9 domesticated animal sources around this shellfish culture area. Jackknife analysis of the complete (GTG)₅-PCR DNA fingerprint library indicated that isolates were assigned to the correct source groups with an 84.28% average rate of correct classification. Based on one-year source tracking data, the dominant sources of E. coli were swine, chickens, ducks and cows in this water area. Moreover, annual and spatial changes of E. coli concentrations and host sources may affect the level and distribution of zoonotic pathogen species in waters. Our findings will further contribute to preventing fecal pollution in aquatic environments and quality control of shellfish.     

Hydrogeomorphological Controls on Groundwater Quality in the Rattaphum Catchment (Songkhla Lake Basin), Thailand

The Rattaphum Catchment comprises four major hydrogeomorphic units: mountains, footslopes, plains and inland swamps around a lake system. The area accommodates three main agro-ecosystems: vegetable, rubber and fruits. During the high-rainfall period, groundwater levels rise near to the soil surface in all agro-ecosystems. The high water levels remain for 3–4 months in the coastal plain, while in other areas the groundwater level fluctuates according to the intensity of rainfall events during the 2–3 months of the rainy season. Groundwater salinity is higher near Songkhla Lake and decreases rapidly inland. It is generally lower near streams. Salinity is also lower during periods of higher recharge, increasing slightly during the dry season due to leaching of chemicals from the agricultural areas. In the saturated sandy soils with high hydraulic conductivity and in the vegetable agro-ecosystem areas with high water levels, the NO₃ level in groundwater always exceeds the WHO standard. Variations in NO₃ levels are closely related to patterns of landuse, with higher nitrate levels commonly found in vegetable areas and lower levels associated with fruit and rubber tree plantations. Nearly all groundwater and surface water is contaminated by coliform bacteria, with the level of contamination controlled by groundwater levels, the amount of rainfall and farm activities. Vegetable agro-ecosystems, which have the most intensive cropping system, were found to be the most polluted. In all of the agro-ecosystems, the most polluted period coincided with the first series of rainfall events.     

ACCOMMODATING CHANGE OF BACTERIAL INDICATORS IN LONG TERM WATER QUALITY DATASETS1

ABSTRACT: In 1996, the State of Oregon adopted a water quality standard based on Escherichia coli (E. coli), recognizing E. coli as an indicator of pathogenic potential. The Oregon Department of Environmental Quality (DEQ) began analysis for E. coli that same year. The Oregon DEQ continued collection and analysis of fecal coliform (a prior indicator organism) for data input to bacterial loading models and the Oregon Water Quality Index (OWQI). The OWQI is a primary indicator of general water quality for the Oregon DEQ and the Oregon Progress Board. The objective of this study was to develop a regression relationship between fecal coliform and E. coli. This relationship would fill data gaps and extend water quality models and indicators. Water quality policy is better informed by the ability of these extended water quality models to determine whether water quality meets present or would have met past bacterial standards. Monitoring resources spent on dual bacterial analyses could be conserved. This study also showed that changes to OWQI values (as a result of changing bacterial indicators) were minimal, and corresponded to improved characterization of water quality with respect to pathogenic potential.     

ESCHERICHIA COLI SURVIVAL IN MANTLED KARST SPRINGS AND STREAMS,NORTHWEST ARKANSAS OZARKS,USA1

Recent studies indicate fecal coliform bacterial concentrations, including Escherichia coli (E. coli), characteristically vary by several orders of magnitude, depending on the hydrology of storm recharge and discharge. E. coli concentrations in spring water increase rapidly during the rising limb of a storm hydrograph, peak prior to or coincident with the peak of the storm pulse, and decline rapidly, well before the recession of the storm hydrograph. This suggests E. coli are associated with resuspension of sediment during the onset of turbulent flow, and indicates viable bacteria reside within the spring and stream sediments. E. coli inoculated chambers were placed in spring and stream environments within the mantled karst of northwest Arkansas to assess long term (> 75 days) E. coli viability. During the 75‐day study, a 4‐log die‐off of E. coli was observed for chambers placed in the Illinois River, and a 5‐log die‐off for chambers placed in Copperhead Spring. Extrapolation of the regression line for each environment indicates E. coli concentration would reach 1 most probable number (MPN)/100 g sediment at Copperhead Spring in about 105 days, and about 135 days in the Illinois River, based on a starting inoculation of 2.5 × 107 MPN E. coli/100 g of sediment. These in situ observations indicate it is possible for E. coli to survive in these environments for at least four months with no fresh external inputs.     

秦皇岛市沿岸海水浴场水质现状分析及污染防治对策

本文根据多年海水浴场监测数据，应用数理统计方法和污染指数法，对秦皇岛市沿岸海水浴场的水质进行了现状质量评价及趋势分析，对保持海水浴场的水质质量提出了相应的对策。     

渤、黄海沿岸几种经济贝类及其生存环境中的粪大肠菌群

报道了渤、黄海 6个重点沿岸海域 (吕泗、青岛、北戴河、盘锦、大连和庄河 )表层海水和几种经济贝类中的粪大肠菌群 (FC)检测结果。结果表明 ,16个表层海水样品中的FC含量波动范围为 <4 0～≥ 4 80 0 0 /L。 36个经济贝类样品中的FC数为 <2～≥ 2 4 0 0 /g鲜重。上述结果说明 ,渤、黄海某些重点沿岸海域 (如青岛、北戴河沿岸 )受人畜粪便等生活污水和人为活动影响较严重 ,海域环境卫生状况不容乐观 ,需加强规划和治理力度。     

浑河（抚顺段）水质粪大肠菌群污染现状研究

近年来，随着城市垃圾、生活污水、工业废水、人畜粪便和医院废水等的不合理排放，导致浑河（抚顺段）水质受到严重污染。粪大肠菌群（Fecal Coliform）是检验水质污染的一个重要生物指标，主要来源于人和混血动物的粪便，对水域进行粪大肠菌群的检测并结合理化分析，可以准确定出水体污染的性质和程度，从而可为水体的污染状况和程度的评估提供科学的依据。本文以粪大肠菌群作为水质粪便污染指标，于2005年监测了浑河（抚顺段）水体粪便污染情况，同时监测了水质COD值。其结果表明，浑河（抚顺段）水体粪便污染严重，粪大肠菌群与COD呈现良好的相关关系。     

Linking on-farm dairy management practices to storm-flow fecal coliform loading for California coastal watersheds

How and where to improve water quality within an agricultural watershed requires data at a spatial scale that corresponds with individual management decision units on an agricultural operation. This is particularly true in the context of water quality regulations, such as Total Maximum Daily Loads (TMDLs), that identify agriculture as one source of non-point source pollution through larger tributary watershed scale and above and below water quality investigations. We have conducted a systems approach study of 10 coastal dairies and ranches to document fecal coliform concentration and loading to surface waters at the management decision unit scale. Water quality samples were collected on a storm event basis from loading units that included: manure management systems; gutters; storm drains; pastures; and corrals and lots. In addition, in-stream samples were collected above and below the dairy facilities and from a control watershed, managed for light grazing and without a dairy facility or human residence and corresponding septic system. Samples were analyzed for fecal coliform concentration by membrane filtration. Instantaneous discharge was measured for each collected sample. Storm runoff was also calculated using the curve number method (SCS, 1985). Results for a representative dairy as well as the entire 10 dairy data set are presented. Fecal coliform concentrations demonstrate high variability both within and between loading units. Fecal coliform concentrations for pastures range from 206 to 2,288,888 cfu/100 ml and for lots from 1,933 to 166,105,000 cfu/100 ml. Mean concentrations for pastures and lots are 121,298 (SE=62,222) and 3,155,584 (SE=1,902,713) cfu/100 ml, respectively. Fecal coliform load from units of concentrated animals and manure are significantly more than units such as pastures while storm flow amounts were significantly less. Compared with results from earlier tributary scale studies in the watershed, this systems approach has generatedwater quality data that is beneficial for management decisions because of its scale and representation of current management activities. These results are facilitating on-farm changes through the cooperative efforts of dairy managers, regulatory agency staff, and sources of technical and financial assistance.