BACTERIAL RELATIONSHIPS IN STORMWATERS1

ABSTRACT: Data were developed within a three-year period for indicator bacteria and three species of bacterial pathogens following rural storm event hydrographs. The first flush concept was confirmed in all hydrographs. Bacterial density peaking occurred at or before the hydrograph peaks. FC and FS values were higher in more developed areas than the primary rural test site and their numerical ratios followed similar trends. Chlorine demand of storm waters varied between 8 and 16 mg/l and, the ozone requirement was greater than 32 mg/l in the same waters. Aftergrowth of total coliform bacteria occurred following chlorine and ozone doses of 16 mg/l and 32 mg/l respectively. Fecal coliform, fecal streptococci, Salmonella sp., and Pseudomonas sp. all were reduced to near detectable limits by the disinfectants up to 8 days. Staphylococcus sp. demonstrated a propensity to restablish their populations. Multiple regression analysis of the bacterial groups and species in storm waters suggested the fecal streptococci to have been the most useful group in evaluating bacterial storm water quality, with staphylocci have been closely related insofar as their statistical significance was concerned.     

ENHANCING FECAL COLIFORM TOTAL MAXIMUM DAILY LOAD MODELS THROUGH BACTERIAL SOURCE TRACKING1

ABSTRACT: Surface water impairment by fecal coliform bacteria is a water quality issue of national scope and importance. In Virginia, more than 400 stream and river segments are on the Commonwealth's 2002 303(d) list because of fecal coliform impairment. Total maximum daily loads (TMDLs) will be developed for most of these listed streams and rivers. Information regarding the major fecal coliform sources that impair surface water quality would enhance the development of effective watershed models and improve TMDLs. Bacterial source tracking (BST) is a recently developed technology for identifying the sources of fecal coliform bacteria and it may be helpful in generating improved TMDLs. Bacterial source tracking was performed, watershed models were developed, and TMDLs were prepared for three streams (Accotink Creek, Christians Creek, and Blacks Run) on Virginia's 303(d) list of impaired waters. Quality assurance of the BST work suggests that these data adequately describe the bacteria sources that are impairing these streams. Initial comparison of simulated bacterial sources with the observed BST data indicated that the fecal coliform sources were represented inaccurately in the initial model simulation. Revised model simulations (based on BST data) appeared to provide a better representation of the sources of fecal coliform bacteria in these three streams. The coupled approach of incorporating BST data into the fecal coliform transport model appears to reduce model uncertainty and should result in an improved TMDL.     

BACTERIAL POPULATIONS OF AQUATIC SYSTEMS RECEIVING DIFFERENT TYPES OF STRESS1

ABSTRACT: Bacterial populations in a fast flowing stream receiving chemical wastes and in a slower flowing pond receiving a thermal addition 3–5°C above ambient temperature were compared with populations in a nonpolluted converging stream and an adjacent unheated pond. Parameters measured were total aerobic heterotrophic bacteria, bacterial diversity, percent chromagens of the total bacterial populations, and water temperature. Analyses of monthly samples plated on dilute Standard Plate Count Agar indicated that chemical additives to the waste stream significantly decreased the percent of chromagenic bacteria, and that thermal stress significantly altered total counts and bacterial diversity in the flowing pond. The effects of potential pollutants on these aquatic systems were assessed and are discussed on the basis of results obtained over a 16-month period.     

Bacterial diversity in selenium reduction of agricultural drainage water amended with rice straw

Bacterial reduction of the Se oxyanions selenate [Se(VI)] and selenite [Se(IV)] to elemental selenium [Se0] is an important biological process in removing Se from drainage water. This study was conducted to characterize the molecular diversity of bacterial populations involved in Se reduction of drainage water amended with rice (Oryza sativa L.) straw and also to monitor the bacterial community shifts during the course of the study. Selenate was removed in the drainage water by the bacteria 5 to 6 d after addition of rice straw. Six Se(VI)- and 32 Se(IV)-reducing bacteria were isolated from rice straw containing sterilized drainage water. Three Se(VI)- and two Se(IV)-reducing bacteria were also isolated from the drainage water. Identification of Se(VI)- and Se(IV)-reducing bacteria by 16S rDNA sequence analysis showed a broad phylogenetic diversity in Se-reducing assemblages. Three major phyla (Proteobacteria, Actinobacteria, and Firmicutes) of bacterial domain with numerous classes, orders, and families constituted the Se-reducing bacterial community. We documented changes in the composition of bacterial assemblages in the drainage water amended with rice straw using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. The Shannon-Weaver index (H') revealed higher bacterial diversity at Day 6 in the sterilized and Day 4 in the non-sterilized drainage water amended with rice straw. The results of this study suggest that rice straw, a good source of carbon and energy, harbors a wide range of bacteria useful in Se reduction and may be used in removing Se from drainage water.     

Survival potential of Escherichia coli and Enterococci in subtropical beach sand: implications for water quality managers

Fecal bacteria have traditionally been used as indicator organisms to monitor the quality of recreational waters. Recent work has questioned the robustness of traditional indicators, particularly at seawater bathing beaches. For example, a study of Florida beaches found unexpectedly high abundances of Escherichia coli, fecal coliforms, and enterococci in beach sand. The aim of the present study was to explain these abundances by assessing the survival of E. coli and enterococci in beach sand relative to seawater. We used a combination of quantitative laboratory mesocosm experiments and field observations. Results suggested that E. coli and enterococci exhibited increased survivability and growth in sand relative to seawater. Because fecal bacteria are capable of replicating in sand, at least under controlled laboratory conditions, the results suggest that sand may be an important reservoir of metabolically active fecal organisms. Experiments with "natural" mesocosms (i.e., unsterilized sand or water rich in micropredators and native bacteria) failed to show the same increases in fecal indicators as was found in sterile sand. It is postulated that this was due to predation and competition with indigenous bacteria in these "natural" systems. Nonetheless, high populations of indicators were maintained and recovered from sand over the duration of the experiment as opposed to the die-off noted in water. Indicator bacteria may wash out of sand into shoreline waters during weather and tidal events, thereby decreasing the effectiveness of these indicators as predictors of health risk and complicating the interpretations for water quality managers.     

The potential of epiphytic hydrocarbon-utilizing bacteria on legume leaves for attenuation of atmospheric hydrocarbon pollutants

The leaves of two legumes, peas and beans, harbored on their surfaces up to 9×10? cells g?1 of oil-utilizing bacteria. Less numbers, up to 5×10? cells g?1 inhabited leaves of two nonlegume crops, namely tomato and sunflower. Older leaves accommodated more of such bacteria than younger ones. Plants raised in oily environments were colonized by much more oil-utilizing bacteria than those raised in pristine (oil-free) environments. Similar numbers were counted on the same media in which nitrogen salt was deleted, indicating that most phyllospheric bacteria were probably diazotrophic. Most dominant were Microbacterium spp. followed by Rhodococcus spp., Citrobacter freundii, in addition to several other minor species. The pure bacterial isolates could utilize leaf tissue hydrocarbons, and consume considerable proportions of crude oil, phenanthrene (an aromatic hydrocarbon) and n-octadecane (an alkane) in batch cultures. Bacterial consortia on fresh (but not on previously autoclaved) leaves of peas and beans could also consume substantial proportions of the surrounding volatile oil hydrocarbons in closed microcosms. It was concluded that phytoremediation through phyllosphere technology could be useful in remediating atmospheric hydrocarbon pollutants.     

Changes in the populations ofBacillus thuringiensis H-14 andBacillus sphaericus applied to vector breeding sites

Summary A dark brown mutant ofBacillus thuringiensis H-14 (BT-MB24) and a macrofibre mutant ofBacillus sphaericus H5 ab (BS-MS3) were applied to mosquito breeding habitats such as rain-water pools, casuarina garden pits, paddy fields and cesspits. The population of these bacilli in the water and soil of these habitats was monitored. The results show that the population of the two bacteria recovered from the water decrease with simultaneous increase in the soil populations within one hour of application: by day 19, the bacilli are virtually absent from the water. Only a few cells remain viable in the water for up to 200 days and in the soil for up to 270 days. Even though both these bacilli persist in the waters for a long time at about 100 CFU mL^–1 they do not cause any significant reduction in the mosquito larval density.The authors form part of the research team at the Vector Control Research Centre of the Indian Council of Medical Research, Indira Nagar, Pondicherry.     

Potential Impacts of Stormwater Runoff on Water Quality in Urban Sand Pits and Adjacent Groundwater1

Whittemore, Donald O., 2012. Potential Impacts of Stormwater Runoff on Water Quality in Urban Sand Pits and Adjacent Groundwater. Journal of the American Water Resources Association (JAWRA) 48(3): 584-602. DOI: 10.1111/j.1752-1688.2011.00637.x Abstract: Entrance of stormwater runoff into water-filled pits and adjacent aquifers is a contamination concern. The water and sediment quality in several sand pits and surrounding groundwater in Wichita, Kansas, were studied to comprehensively address stormwater runoff impact. The pits are used for residential development after sand and gravel mining. Water samples were analyzed for inorganic constituents, bacteria, and 252 organic compounds, and pit sediments for inorganic components and 32 organic chemicals. Although many pesticide and degradate compounds were found in the pit and well waters, none of these chemicals exceeded existing health levels. Other organic contaminants were detected in the waters, with those exceeding health levels at one site attributed to an undiscovered groundwater contamination plume and not to stormwater runoff. Persistent insecticides and polychlorinated biphenyls detected in sediment of two pits are related to the age of residential development. The concentration distributions of pesticides and other organics at most of the sites, as well as iron, manganese, and ammonia patterns in downgradient well waters relative to upgradient well and pit waters, indicate that groundwater quality at the sites is affected by contaminants entering the pit surface waters. Thus, although current stormwater runoff does not appear to have contaminated sand-pit water and adjacent groundwater above health levels, the data show that the potential exists if stormwater became polluted.     

BACTERIAL LEVELS IN CISTERN WATER SYSTEMS OF NORTHERN KENTUCKY1

ABSTRACT: In rural Northern Kentucky, rainwater is commonly collected from rooftops and stored in cement block cisterns as the sole source of drinking water. Although every cistern system is unique in some aspect of design, use, or maintenance, a bacterial survey of 30 rural Northern Kentucky cistern systems suggests that coliforms and heterotrophic bacteria are common to all types of cistern storage systems. An average of 600 coliforms/ml and 3.6 ± 10⁵ heterotrophic bacteria/ml were detected in water samples from the bottoms of the cistern storage tanks. Bacterial levels in water delivered to household cold tap faucets were similar to the levels found in the storage tanks. When detected, fecal coliforms were recovered throughout the entire system including the household cold tap faucet. Current U.S. regulations for drinking water quality are discussed, with a suggestion that fecal coliform levels may be a more appropriate guideline for interpreting the water quality of individually maintained, nonchlorinated, nonpiped water supplies, such as cistern storage systems.     

A GEOGRAPHIC INFORMATION SYSTEM TO PREDICT NON-POINT SOURCE POLLUTION POTENTIAL1

ABSTRACT: Bacterial densities (total coliform, fecal coliform, and fecal streptococci) and suspended solids in runoff from a feedlot, pasture, and corn field were measured. Densities of fecal coliform were highest from the feedlot but were 1000 to 10,000 times greater than the water quality standard for swimmable waters from all three land uses. Densities of fecal streptococci were highest from the corn field, which suggests that wildlife are the source of bacteria. Fecal coliform/fecal streptococci ratios distinguished cattle from wildlife as the source of bacterial pollution both among land uses and among seasons of the year. Suspended solids concentrations in runoff ranged from 423 to 925 mg/l and were highest from the corn field. A Geographic Information System (GIS), which utilizes a raster or grid-cell format, was developed to include algorithms associated with non-point source pollution. The system accepts digitally mapped information on soil type, topography, and land use. It calculates characteristics such as slope and slope length, and relates these characteristics to soils and land use parameters in order to produce three dimensional maps of runoff potential, sediment pollution potential, and bacterial pollution potential. It offers the advantages of retaining the geographic character of pollution potential information and of conveying in three-dimensional graphical terms the effects of topography, soil type, land use, and land management practices.     

INCREASING WATER SUPPLY BY MIXING OF FRESH AND SALINE GROUND WATERS1

ABSTRACT: The quality of ground water in any aquifer takes its final form due to natural mixture of waters, which may originate from different sources. Water quality varies from one aquifer to another and even within the same aquifer itself. Different ground water quality is obtained from wells and is mixed in a common reservoir prior to any consumption. This artificial mixing enables an increase in available ground water of a desired quality for agricultural or residential purposes. The question remains as to what proportions of water from different wells should be mixed together to achieve a desired water quality for this artificial mixture. Two sets of laboratory experiments were carried out, namely, the addition of saline water to a fixed volume of fresh water. After each addition, the mixture volume and the electric conductivity value of the artificially mixed water were recorded. The experiments were carried out under the same laboratory temperature of 20°C. A standard curve was developed first experimentally and then confirmed theoretically. This curve is useful in determining either the volume or discharge ratio from two wells to achieve a predetermined electrical conductivity value of the artificial mixture. The application of the curve is given for two wells within the Quaternary deposits in the western part of the Kingdom of Saudi Arabia.     

Long-term phosphorus immobilization by a drinking water treatment residual

Excessive soluble P in runoff is a common cause of eutrophication in fresh waters. Evidence indicates that drinking water treatment residuals (WTRs) can reduce soluble P concentrations in P-impacted soils in the short term (days to weeks). The long-term (years) stability of WTR-immobilized P has been inferred, but validating field data are scarce. This research was undertaken at two Michigan field sites with a history of heavy manure applications to study the longevity of alum-based WTR (Al-WTR) effects on P solubility over time (7.5 yr). At both sites, amendment with Al-WTR reduced water-soluble P (WSP) concentration by >or=60% as compared to the control plots, and the Al-WTR-immobilized P (WTR-P) remained stable 7.5 yr after Al-WTR application. Rainfall simulation techniques were utilized to investigate P losses in runoff and leachate from surface soils of the field sites at 7.5 yr after Al-WTR application. At both sites, amendment with Al-WTR reduced dissolved P and bioavailable P (BAP) by >50% as compared to the control plots, showing that WTR-immobilized P remained nonlabile even 7.5 yr after Al-WTR amendment. Thus, WTR-immobilized P would not be expected to dissolve into runoff and leachate to contaminate surface waters or groundwater. Even if WTR-P is lost via erosion to surface waters, the bioavailability of the immobilized P should be minimal and should have negligible effects on water quality. However, if the WTR particles are destroyed by extreme conditions, P loss to water could pose a eutrophication risk.     

THE EFFECTS OF ARTIFICIAL CIRCULATION ON A SMALL NORTHEASTERN IMPOUNDMENT1

ABSTRACT: Artificial circulation was applied at East Sidney Lake, a small, eutrophic impoundment in New York, to improve the water quality of the reservoir and tailwater. Treatment was successful at both reducing the stability of the reservoir and maintaining higher mean oxygen concentrations in the bottom waters. Discharge waters had lower metals and phosphorus concentrations during treatment years. However, vertical temperature differences, although minimal, were still sufficient to permit chemical stratification and some phosphorus release from the sediments. Frequent mixing events during periods of low stability, and runoff from storm events, also appeared to increase transport of phosphorus into the epilimnion. Overall, treatment did not result in decreases in algal populations or improvements in water clarity.     

Selenium stable isotope ratios in California agricultural drainage water management systems

Selenium stable isotope ratios are known to shift in predictable ways during various microbial, chemical, and biological processes, and can be used to better understand Se cycling in contaminated environments. In this study we used Se stable isotopes to discern the mechanisms controlling the transformation of oxidized, aqueous forms of Se to reduced, insoluble forms in sediments of Se-affected environments. We measured 80Se/76Se in surface waters, shallow ground waters, evaporites, digested plants and sediments, and sequential extracts from several sites where agricultural drainage water is processed in the San Joaquin Valley of California. Selenium isotope analyses of samples obtained from the Tulare Lake Drainage District flow-through wetland reveal small isotopic contrasts (mean difference 0.7%) between surface water and reduced Se species in the underlying sediments. Selenium in aquatic macrophytes was very similar isotopically to the NaOH and Na2SO3 sediment extracts designed to recover soluble organic Se and Se(0), respectively. For the integrated on-farm drainage management sites, evaporite salts were slightly (approximately 0.6%) enriched in the heavier isotope relative to the inferred parent waters, whereas surface soils were slightly (approximately 1.4%) depleted. Bacterial or chemical reduction of Se(VI) or Se(IV) may be occurring at these sites, but the small isotopic contrasts suggest that other, less isotopically fractionating mechanisms are responsible for accumulation of reduced forms in the sediments. These findings provide evidence that Se assimilation by plants and algae followed by deposition and mineralization is the dominant transformation pathway responsible for accumulation of reduced forms of Se in the wetland sediments.     

Legitimizing Fluvial Ecosystems as Users of Water: An Overview

We suggest that fluvial ecosystems are legitimate users of water and that there are basic ecological principles guiding the maintenance of long-term ecological vitality. This article articulates some fundamental relationships between physical and ecological processes, presents basic principles for maintaining the vitality of fluvial ecosystems, identifies several major scientific challenges and opportunities for effective implementation of the basic ecological principles, and acts as an introduction to three specific articles to follow on biodiversity, biogeochemistry, and riparian communities. All the objectives, by necessity, link climate, land, and fresh water. The basic principles proposed are: (1) the natural flow regime shapes the evolution of aquatic biota and ecological processes, (2) every river has a characteristic flow regime and an associated biotic community, and (3) aquatic ecosystems are topographically unique in occupying the lowest position in the landscape, thereby integrating catchment-scale processes. Scientific challenges for the immediate future relate to quantifying cumulative effects, linking multidisciplinary knowledge and models, and formulating effective monitoring and assessment procedures. Additionally, forecasting the ecological consequences of changing water regimes is a fundamental challenge for science, especially as environmental issues related to fresh waters escalate in the next two to three decades.     

THE EFFECTS OF SELECTED HERBICIDES ON BACTERIAL POPULATIONS IN AN AQUATIC ENVIRONMENT1

ABSTRACT: Heterotrophic, mesophilic bacteria derived from, and maintained in, a freshwater environment were subjected to three classes of herbicides. Diuron, 2,4,5-Trichlorophenoxyacetic acid, and paraquat, used as water soluble solutions, were added (0.7 and 1.4 mgA) to a laboratory culture of bacteria. Total numbers of the bacteria, representing several genera, were monitored for alteration of numbers and types. Temperature, pH, and dissolved oxygen were monitored and the culture medium was tested for residual herbicide. Alterations observed in populations were considered to result from herbicide additions. Each herbicide tested was found to affect bacterial populations differently. Reasons for observed differences are discussed. In this aquatic environment the herbicides remained qualitatively measurable for periods up to three weeks.     

METABOLIC RESPONSES OF AQUATIC BACTERIAL POPULATIONS TO SELECTED INSECTICIDES1

ABSTRACT: Indigenous bacterial populations from a fresh water reservoir were treated by adding five mg/1 Sevin or Malathion to the water at 23, 28, and 33 C. The degradation of Sevin was evidenced by the increased uptake of O₂ as measured by Warburg manometry. The principal degradation product of Sevin, 1-naphthol, appeared to stimulate metabolic activity of these populations to the same extent as the parent compound. The addition of Malathion to this system appeared, on the other hand, to suppress metabolic activity to some degree. Warburg manometry was shown to be a useful, rapid method for detecting effects of insecticides on aquatic microbial populations.     

Acidification and recreational fisheries in Finland: A mail survey of potential impacts

In Finland, small forest lakes and rivers in the northern part of the country are more sensitive to acidic deposition than other Finnish waters. In some lakes, acid-sensitive fish populations have declined. A nationwide survey of fishers showed that, at present, the number of fishers whose primary fishing waters are affected by airborne acidification is negligible compared to the estimated total number of adult fishers (1.1 million). The proportion of the fishers who mainly fish in water types sensitive to airborne acidification is considerable, 3% for the rivers in northern Finland and 21% for small forest lakes. There is general concern among fishers about the effects of acidification. Changes in the fishing waters are attributed to acidification by 5–10% of the fishers, although in most cases other information about the fishing waters rules out acidification as an explanation for the changes. Among those who fish in sensitive types of waters, a willingness to mitigate potential damages was reported by approximately one third of all fishers. Clear differences in the willingness to rehabilitate the fishery were observed in relation to the importance of fishing as a spare time activity and the distance between the fishing waters and a home or summer cottage.     

FACTORS AFFECTING SALINITY REDUCTION IN LAKE TARPON,PINELLAS COUNTY,FLORIDA1

ABSTRACT: Following an enclosure of a sink-hole connecting Lake Tarpon to the Gulf of Mexico, the chloride concentration of lake waters decreased. Water and chloride budgets for the lake in 1975 were prepared, and predictions using the model of Lerman and Brunskill (1971) were made as to the time required for the lake to achieve fresh water status. Model verification indicated good agreement with predictions in 1976; however, data on [C1^-] for 1977 and 1978 are not as supportive of the model used. The information concerning the Lake Tarpon watershed provided by this latter fact is discussed.     

Total site: wastewater minimization: Wastewater reuse and regeneration reuse

Analysis of technological wastewater streams in a refinery and petrochemical complex was carried out. Wastewater flowrates, temperatures, pH and pollutant contents were measured. Regarding the characteristics of the individual waters, possible connections between water outflows from the processes or process units and potential water consumers were determined. Possibilities to reduce the flowrate of technological wastewater with wastewater reuse or preliminary regeneration and reuse were found. The consumption of fresh water could be lowered by 11.2 m³/h, reducing the treatment system load and prolonging its residence time by 7%. The payback period for the changes proposed in the petrochemical plants is 6 months with annual savings of US$27 630. The payback period for the changes proposed in the refinery is 11 days with annual savings of US$15 500.