The use of clams as bioindicator of fecal pollution in seawater

The coastal waters of Kuwait are widely used for bathing during the long summer season. In order to assess the water quality along the beaches, a new approach was developed. It involves the use of clam, Circenita callipyga, as a bioindicator for seawater pollution by fecal coliform bacteria (FC), antibotic resistant fecal coliform (ABR-FC) and Salmonella spp. These organisms were detected in clam and water samples and the efficiency of clam in concentrating Salmonella was confirmed. The number of FC and ABR-FC in clam and water samples were compared and a higher number was detected in clams than in water. Five isolates of Salmonella from clams were also multidrug resistant. The data suggests that clam can be used as a bioindicator of seawater pollution and is preferable to direct testing of water. The resistance to antibiotics in E. coli isolated from water and clams collected at the same time and site was of similar pattern and was determined by R-plasmid.     

Fecal coliform and E. coli estimates,tip of the iceberg

Pure cultures of E. coli, Klebsiella and Enterobacter, obtained from hospital patients and from natural waters were tested for their growth patterns by spread plate and membrane filtration procedures at the following temperatures; 35°, 41.5°, 43°, 44.5°, and 35°C for 4 h followed by 18 h at 44.5°C. Results indicated that 44.5°C incubation produces the lowest population estimate and that the application of the membrane filtration technique also reduced the potential population. Three water samples collected during June, August and November were tested for fecal coliform and E. coli populations, with 11 different media (broth and agar) and incubation temperatures of 35°, 41.5°, 43°, 44.5°, and 35°C for 4 h followed by 18 h at 44.5°C. During the study, isolates were collected from all positive MPN tubes at each temperature and from each MF medium-temperature regime, 24 to 50 isolates were collected. From the isolate data corrected coliform (oxidase negative), fecal coliform and E. coli population estimates were made. A sample of feces was diluted in lake water and maintained at 20°C for 56 days. Samples were collected at various times and tested for fecal coliform densities using five media and the same temperature regime as for the lake water samples. Data from these studies indicate that, depending on the age of the population being measured, the temperature of the water sample, and the temperature-media-procedure combination used, fecal coliform and E. coli population estimate techniques measure from 5 to 100% of the potential population.     

Relationship of biotic and abiotic factors to recruitment patterns in Margaritifera margaritifera

We investigated relationships of biotic and abiotic factors to recruitment patterns of the endangered freshwater pearl mussel (Margaritifera margaritifera) in 10 Swedish streams. We found that the maximum proportion of gravid mussels did not differ between streams with and without recent recruitment. Moreover, the mean glochidial load on trout (Salmo trutta), which was positively related to adult mussel density, did not differ significantly between these stream types. Thus, the larval stages of the freshwater pearl mussel were not related to recruitment failure. Instead, recruitment is probably hindered at the next stage in the life history of the mussels, the benthic stage, and may be related to sedimentation as turbidity was four times greater in streams lacking recent recruitment than in streams with recent recruitment. Furthermore, we found that juvenile mussel density was positively related to the number of glochidial infections per stream area in streams with ongoing recruitment, indicating that successful recruitment in these streams may depend on both mussel and trout density. Future research should thus examine biotic interactions between mussels and trout as well as the effects of sedimentation on benthic-living mussels.     

Fecal coliform dispersal by rain splash on slopes

The movement of fecal pathogens from land to surface and ground water are of great interest because of the public health implications. Non-structural best management practices that control the timing, volume, and placement of animal manures are commonly used to limit opportunities for fecal pathogens to enter water bodies. Increased infiltration capacity, water and waste diversions, and vegetated filter strips are used to control fecal pathogen movement in surface runoff. Fecal pathogens transported by rain splash could conceivably bypass physical barriers. The relationship between slope angle and the transport of fecal coliform bacteria by rain splash was studied. It was hypothesized that there would be a significant down slope transport of fecal coliform bacteria by raindrops falling on a bare soil surface inoculated with fecal coliform bacteria. Slopes from 0° to 40.8° were studied. The mean splash distance for fecal coliforms was less than 50 mm in all directions at 0° slope and more than 500 mm in the downslope direction on a 40.8° slope. Maximum splash distances ranged from about 400 mm on the horizontal surface to more than 1900 mm in the downslope direction on the 40.8° slope. Sequential downhill movement of fecal coliform (FC) bacteria by repeated rain splash could transport FC directly to water bodies or areas of saturation excess where they will become entrained in overland runoff. Further studies on raindrop and rainfall characteristics, as well as surface cover and soil characteristics, will be necessary to more fully understand the mechanisms of FC transport on sloping land by rain splash.     

Indicator bacteria concentrations as affected by hydrologic variables in the Apalachicola river,Florida

Concentrations of fecal coliform and fecal Streptococcus bacteria were monitored in the Apalachicola River, Florida, at various river stages. Bacteria transported by the river may eventually be assimilated by estuarine filter feeders, including shellfish. Sources along the river contributed to relatively high coliform and coliform: Streptococcus ratios at a few sites upstream, but there was a general decreasing trend in coliform numbers in a downstream direction. The data suggested that coliform densities depend not only on discharge, but also on factors such as whether the river stage is rising or falling, whether the flood is in an early or late phase, and the volume of the current peak relative to earlier peaks. A regression model indicated that 53 % of fecal coliform variability could be accounted for by river discharge and 32% could be accounted for by other hydrologic characteristics of the flood.     

Identification of an Assemblage of Indicator Organisms to Assess Timing and Source of Bacterial Contamination in Groundwater

Bacterial contamination of drinking water wells is a commonproblem in many rural areas. Some of this contamination may berelated to manure spreading or housing of livestock; another source is on-site septic systems. Current indicator organisms are able to detect the presence of fecal contamination, but where there may be more than one potential source of fecal material, the current indicators are unable to ascertain the origin. This laboratory investigation was undertaken to determine the longevity and reliability of a selected suite of indicator organisms. Total coliform, fecal coliform, fecal streptococci and Clostridium perfringens were monitoredin a simulated contaminated groundwater environment for 6 months. All four indicator organisms were present at the end of6 months. The number of fecal streptococi bacteria decreased most noticeably, allowing assessment of relative age of contamination. C. perfringens was found to be a reliableindicator of contamination from animal manure. Fecal material from 28 different animals and three septic systems were assessed for the presence of the indicator organisms. Totalcoliform, fecal coliform and fecal streptococci were present in the fecal material of all animals tested including reptiles.C. perfringens was detected in feces from all but two of the animals assessed. Using an assemblage of indicator organisms provides more information regarding source and timingof contamination than just testing for total coliform and fecalcoliform bacteria.     

Comparison of mussels and crustacean plankton to monitor heavy metal pollution

The ability of freshwater organisms (mussels — Unio pictorum L. and crustacean plankton —Cladocera and Copepoda species) to monitor heavy metal pollution was compared under field conditions, near the effluent discharge of a sewage water treatment plant at Lake Balaton (Hungary). The mussels were transferred from their less polluted habitat to the study area. The crustacean plankton was collected at this site The concentrations of Hg Cd Cr Cut Pb, Zn, and Fe were measured m the gills of the transplanted mussels as well as the natural zooplankton in the summer period, using the AAS method. Both mussel gills and the zooplankton showed periodically high Fe-, Zn-, and Cu-concentrations. An elevated level of Hg was only observed in mussels, while high Pb- and Cr-concentrations were found only in crustacean plankton. Accordingly the zooplankton seems a more suitable model for monitoring heavy metal pollution under these field conditions.     

Assessment of the Potential Cyto�CGenotoxicity of the Nonsteroidal Anti-Inflammatory Drug (NSAID) Diclofenac on the Zebra Mussel (Dreissena polymorpha)

A battery of eight biomarkers was used on the freshwater bivalve Dreissena polymorpha in order to evaluate potential sub-lethal effects of the nonsteroidal anti-inflammatory drug diclofenac (DCF; 2-[(2,6-dichlorophenyl)amino]phenylacetic acid). By an in vivo approach, mussels were exposed for 96 h to increasing concentrations (0.3, 1, and 2 nM) of DCF perfectly comparable with current surface water levels. We determined the single cell gel electrophoresis assay, the apoptotic frequency (DNA Diffusion assay), the micronucleus test (MN test), and the lysosomal membrane stability (Neutral Red Retention Assay) in mussel hemocytes. Moreover, the activity of catalase, superoxide dismutase, glutathione peroxidase, and the phase II detoxifying enzyme glutathione S-transferase was measured in the cytosolic fraction extracted from a pool of entire bivalves to reveal possible alterations of the oxidative status of exposed specimens. The biomarker battery pointed out a negligible cyto- and genotoxicity on zebra mussel hemocytes since only a slight decrease of lysosomal membrane stability from baseline levels was measured at the end of exposures at the highest concentration (2 nM). In addition, environmental concentrations of DCF seem to have a negligible effect on the activities of antioxidant and detoxifying enzymes.     

江西青岚湖五种淡水蚌遗传多样性的微卫星DNA分析

利用北美Epioblasma capsaeformis（蚌科）和中欧Margaritifera margaritifera L.（珍珠蚌科）两种淡水双壳类的20对微卫星引物对江西青岚湖五种淡水蚌群体进行了PCR扩增，筛选出8对多态性较高的引物，并用这8个微卫星座位分别对三角帆蚌、褶纹冠蚌、洞穴丽蚌、射线裂脊蚌和中国尖嵴蚌五种蚌类群体进行了遗传多样性分析。结果表明：不同蚌类群体的平均等位基因数为2.8750～4.000，平均观测杂合度（HO）为0.4417～0.6333，平均期望杂合度（HE）为0.4430～0.5706，平均多态信息含量（PIC）为0.368～0.498，五个群体表现出较高的遗传多样性。有多个座位在不同蚌类群体中偏离哈代－温伯格平衡。五种蚌类群体间的遗传距离在0.6228与1.4724之间，三角帆蚌和褶纹冠蚌之间的遗传距离最大，射线裂脊蚌和洞穴丽蚌之间的遗传距离最小。     

Comparison of Fecal Coliform Before and After Wastewater Treatment Facility: a Case Study near a Coastal Town in the Southeastern USA

A central wastewater treatment facility was built in 1997 for the town of Suwannee that eliminated 850 inadequately operating on-site sewage treatment and disposal systems. During a study in 1989?C1990, Salmonella were detected in Suwannee River water samples upstream and downstream of the town of Suwannee. This study presents the findings of fecal coliform distribution between the years 1996 and 2009 in canals and the main stem of Suwannee River near the town of Suwannee, a coastal area in southeastern USA. Fecal coliforms were measured and assessed to evaluate the water quality before and after the installation of the central wastewater treatment facility. In the canals nearby the town of Suwannee, significant differences in fecal coliform concentrations were detected between the samples collected before and after the operation of the central wastewater treatment facility. Average fecal coliform of 537 most probable number (MPN)/100?ml in the canals in 1996 was reduced to 218?MPN/100?ml after the operation of wastewater treatment facility. The fecal coliform levels in canals decreased significantly in the last 13?years. Even though the average fecal coliform levels in the river was reduced from 170 to 86?MPN/100?ml before and after the installation of the wastewater treatment facility, respectively, the difference was not statistically significant.     

The recent and rapid spread of the zebra mussel (Dreissena polymorpha) in Great Britain

This paper reviews the current, apparently rapid spread of zebra mussels (Dreissena polymorpha) in Britain, discusses the possible causes of this spread, considers the potential ecological consequences, and looks at what measures could be undertaken to minimise the impacts of zebra mussels and other invasive pests in Britain's freshwaters. Five out of 27 major water companies reported increases in their regions between 2000 and 2002 and a further three acknowledged their presence. Increases were also reported by the Environment Agency, Broads Authority, angling clubs and boatyards. No one interviewed reported a decrease in zebra mussels between 2000 and 2002. The most notable increases have been in southern, central and eastern England. A newly recorded population of zebra mussels in the River Darent, Kent, contained zebra mussels in dense mats of up to 11,000 individuals m⁻² and up to 20 cm in depth. There is evidence that the ecology of recently invaded sites has been deleteriously affected. A fishing lake in Lancashire has experienced increased water clarity and reduced fish biomass coincidental with the arrival of zebra mussels, while a newly recorded population in Barden Lake, Kent, appears to be having a deleterious impact on native unionid mussels, particularly the swan mussel (Anodonta cygnea) and, more, recently the painter's mussel (Unio pictorum). Repeated surveys in the River Thames, River Great Ouse and Barden Lake showed that the proportion of unionid mussels infested by zebra mussels had increased significantly in all sites studied during the past one to five years.     

Changes in commercially fished shellfish stocks and shorebird populations in the Wash, England

The Wash, in eastern England, supports internationally important populations of 11 species of shorebird. A major commercial shellfishery provides potential conflict between fishermen and nature conservation interests. During the 1990s, high fishing mortality and low recruitment substantially reduced the stocks of cockle (Cerastoderma edule) and mussel (Mytilus edulis). Population models, constructed from estimates of survival and recruitment, indicated that declines in the availability of cockles and mussels were associated with changes in oystercatcher (Haemotopus ostralegus) survival between 1970 and 1998, including three periods of mass mortality, and also the recruitment of juvenile birds to both oystercatcher and knot (Calidris canutus) populations. Emigration of knot may also have taken place. Cockle recruitment was dependent on climatic conditions, whereas mussel populations tended to be stable. The decline in mussel stocks, due to over-fishing, increased the vulnerability of the oystercatcher population to mass-mortality episodes in poor cockle years. The key to preventing major oystercatcher kills in future is to ensure sufficient mussels are available in poor cockle years. Recent cultivation of mussels in inter-tidal areas has been beneficial and is an important management tool for maintaining bird populations.     

Development of Regression-Based Models to Predict Fecal Bacteria Numbers at Select Sites within the Illinois River Watershed, Arkansas and Oklahoma, USA

The Illinois River Watershed is a multi-facet basin with ecological and economic importance to its local stakeholders in northwest Arkansas and northeast Oklahoma, USA. The numbers, transport and sources of fecal bacteria in streams was identified as a research priority of the USDA NRI Water and Watershed Program in 2006, and the objective of this study was to evaluate the relation between fecal bacteria and other measured physicochemical parameters in water samples collected from selected sites throughout the Illinois River Watershed. An existing database (i.e., National Water Information Systems, NWIS) from the US Geological Survey (USGS) was used in this project. The data obtained includes discharge, pH, temperature, dissolved oxygen, Escherichia coli (E. coli), fecal coliform, and fecal streptococci among several other physic-chemical parameters. A synthetic model, based on multi-regression analysis, was developed to predict fecal bacteria numbers at these selected sites based on available USGS NWIS data, and the multiple regressions were significant at almost every site for all three bacteria groups. However, the physicochemical parameters used in the equations were very different across sites and fecal bacteria groups, suggesting that the development of such predictive models is site and bacteria group specific even within one watershed.     

Assessment of the bacteriological quality of rural groundwater supplies in Northern West Virginia

A bacteriological survey was performed on 155 untreated, individual, rural groundwater supplies which included drilled wells, dug wells, and springs. Of these, 105 exceeded the Environmental Protection Agency (EPA) maximum contaminant level of one total coliform per 100 mL. Repeat sampling for 87 of the unacceptable 105 supplies indicated that 76 again exceeded the EPA standard limit. Masked coliforms were detected through confirmation tests in 11 water supplies that exhibited excessive noncoliform colonies (> 50 CFUs/membrane filter). Also, 48% of the supplies contained fecal coliforms and 62% contained fecal streptococci. Bacterial densities were related to the type of water supply with drilled wells containing fewer total coliforms, fecal coliforms, fecal streptococci, and heterotrophic plate count bacteria than dug wells or springs. Water supplies that were shallower, older, and lacking adequate casing characteristically were more heavily contaminated with sanitary indicator bacteria than supplies that were deeper, of more recent construction, and with sufficient casing.     

Effect of heavy metals on growth population of a fecal coliform bacterium Escherichia coli in aquatic environment

The data on the effects of the concentrations (0.5, l, 2, 5 mg L^?1) of the heavy metals, Hg, As, Pb, Cu, Cd, and Cr on changes in growth population of a fecal coliform bacterium Escherichia coli (in term of number of E. coli per 100 mL water) showed a gradual decline in growth population of the fecal coliform bacterium with the increase of exposure time, as well as concentrations of the metals over control data. The effects were markedly recorded with the treatment of 5 mg L^?1. In general, the harmful effects of the metals on growth population of E. coli were found by the treatments in the order: Cd>Ph>Cu>As>Hg>Cr.     

Monitoring of Organic Compounds and Trace Metals During a Dredging Episode in the Göta Älv Estuary (SW Sweden) Using Caged Mussels

The concentrations of selected trace metals, organotins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were determined in caged blue mussels (Mytilus edulis) during dredging operations in the Göta Älv Estuary (SW Sweden). Maximum values of pollutants in mussel tissues were found after the dredging started. Our results showed that the dredging caused mobilization of organotins from the sediments to the water column during the experimental period. Multidimensional scaling (MDS) and cluster analysis were applied to compare and establish relationships between levels of pollutants in mussels and sampling sites during the experimental period. In order to evaluate the biological effects of contaminants, genotoxic damage was measured using the Comet assay, and its potential application for environmental monitoring is discussed.     

Model Assessment of Cattle and Climate Impacts on Stream Fecal Coliform Pollution in the Salmon River Watershed, British Columbia, Canada

A bacterial water quality model (BWQM) was developed and used to evaluate the impacts of cattle farming and climate change on the stream fecal coliform pollution in the Salmon River watershed in south-central British Columbia, Canada. The accuracy of the model simulation was evaluated using the Nash-Sutcliffe coefficient of efficiency (COE). The BWQM simulated the observed field data well, with the values of the COE ranging from 0.76 to 0.78 for the stream flow, from 0.55 to 0.60 for the fecal coliform (FC) concentration, and from 0.85 to 0.89 for the FC loading. The BWQM captured more than 79%, 66%, and 90% variation of the daily stream flow, FC concentration, and FC loading, respectively. The BWQM predicts that between 70% and 80% of the FC were transferred from the cattle farm to the Salmon River through the snowmelt-caused surface runoff during late winter and early spring, with the balance 20% to 30% coming from the soil-lateral flow and the groundwater return flow. The model also indicates that the stream FC concentration is sensitive to the distance of the cattle farm to the Salmon River. The model scenario analysis reveals that the climate change, at an assumed 1??C increment of daily air temperature, results in an increase in the stream FC concentration in the spring, fall, and winter, but there is also a decrease in the summer. The increased air temperature also changes the seasonal pattern of the stream FC concentration. Rainfall can reduce the stream FC concentration and mitigate the impact of the increased air temperature on the stream FC concentration as long as it does not result in a surface runoff or flooding event.     

A Survey of Organotin Compounds in the Northern Adriatic Sea

The extent of pollution with organotin compounds was investigated in water, sediment and bivalve mussels (Mytilus galloprovincialis) from the Northern Adriatic Sea. Butyl-, phenyl- and octyltin species were quantified after extraction and derivatisation by gas chromatography–mass spectrometry in a total of 99 samples from the period from 2000 to 2006. The accuracies of the analytical procedures were checked by spiking of unpolluted water samples and by the analysis of standard reference materials (harbour sediment PACS-2 and mussel tissue ERM-CE 477). Among organotin species analysed in samples butyltins were the predominant. Tributyltin was found to be present in the highest concentrations, suggesting its recent input into the marine environment. Butyltins were detected at all sites surveyed (sum of butyltins was up to 718 ng Sn L^?1, 3,552 ng Sn g^?1 d.w. and 9,991 ng Sn g^?1 d.w. in water, sediment and mussel samples, respectively), phenytins in much lower concentrations (up to 31 ng Sn L^?1, 326 ng Sn g^?1 d.w. and 442 ng Sn g^?1 d.w. in water, sediment and mussel samples) and to a much smaller extent, while octyltins were not detected at any location. The spatial distribution of tributyltin was closely related to boating, with the highest concentrations found in marinas (up to 586 ng Sn L^?1 for water samples, 1,995 ng Sn g^?1 d.w. for sediment and 6,434 ng Sn g^?1 d.w. for mussel samples). The temporal distribution clearly indicates a decrease of organotin pollution at all sites.     

Antioxidant Activity in the Zebra Mussel (Dreissena polymorpha) in Response to Triclosan Exposure

The biocide triclosan (TCS, 5-chloro-2-(2,4-dichlorophenoxy)phenol) is commonly used in several personal care products, textiles, and children??s toys. Because the removal of TCS by wastewater treatment plants is incomplete, its environmental fate is to be discharged into freshwater ecosystems, where its ecological impact is largely unknown. The aim of this study was to determine the effect of TCS on the antioxidant enzymatic chain of the freshwater mollusk zebra mussel (Dreissena polymorpha). We measured the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as the phase II detoxifying enzyme glutathione S-transferase (GST) in zebra mussel specimens exposed to 1 nM, 2 nM, and 3 nM TCS in vivo. The mussels were exposed for 96 h, and the enzyme activities were measured every 24 h. We measured clear activation of GST alone at all three dose levels, which shows a poor induction of the antioxidant enzymatic chain by TCS. CAT and SOD were activated only at 3 nM, while GPx values overlapped the baseline levels.     

Evaluation of Two Techniques: mFC AND mTEC for Determining Distributions of Fecal Pollution in Small,North Carolina Tidal Creeks

Most tidal creeks in North Carolina are closed or partially closed to shellfishing. These creeks often remain closed due to the inability to determine sources of fecal pollution. This study was designed for intensive fecal coliform monitoring of Futch Creek, N.C., to try and determine sources(s) of fecal pollution. Futch Creek is a mildly polluted tidal creek, with marginal levels of fecal coliforms and could potentially be reopened. Problems in interpreting levels of fecal coliforms and pollution risks are two fold and were extremely pronounced in this study. First, several environmental factors have been shown to influence levels of fecal coliforms. Therefore, effects of temperature, salinity, tidal cycles, and rain events on fecal coliform counts were examined. There were higher fecal coliform levels in the warmer temperatures. There was a strong inverse relationship with salinity, with highest fecal coliform counts in the 10–14 g L^-1 range for both the mFC and mTEC counts with no apparent source of pollution. This trend was also observed in three other tidal creeks. Tidal cycles did affect fecal coliform counts with substantially higher counts during low tide and appeared to be more important than rain events. It is apparent that when evaluating several stations in a creek, samples must be taken during the same tidal cycle stage in order to have comparative data. Counts obtained using the mTEC method were consistently higher than mFC counts in all salinity ranges. Basic taxonomic tests were performed on fecal coliforms isolated from three salinity regimes: 0 g L^-1, 10–14 g L^-1, and 23–26 g L^-1. The mFC method in the 10–14 g L^-1 (45%) and 23–26 g L^-1 (70%) salinity range had the highest incidence of false-positive counts (non E. coli). The mTEC method also had the highest incidence of false-positive counts in the 23–26 g L^-1 (27%) and 10–14 g L^-1 (24%), none as high as the mFC method. Therefore, the mTEC method appears to be the better of the two but is still not an ideal approach.