CONCENTRATION AND SOURCES OF FECAL AND ORGANIC POLLUTION IN AN AGRICULTURAL WATERSHED1

ABSTRACT: Fecal contamination and organic pollution of an agricultural drainage in northeast Indiana was high. Bacterial counts (total coliform, TC; fecal coliform, FC; and fecal streptococcus, FS) and biochemical oxygen demand (BOD) were used to assess waste concentrations. Coliform counts indicated that sections of the drainage receiving septic effluent had waste concentrations far in excess of public health standards (mean FC = 550,000/100 ml). Areas of drainage remote from septic tank pollution were found to occasionally meet federal public health standards for whole body contact recreation but generally these areas had twice the allowable limit of 200 FC/100 ml. Bacterial contamination was highest during runoff events when the median values for TC, FC, and FS were 5, 3, and 17 times greater, respectively, than the median values during low stream discharge. Surface flows carried contaminants from unconfined livestock operations and fecally contaminated sediment was transported by high waters. During one runoff event a BOD loading of 36.7 kg/km² was recorded and the peak BOD concentration observed was 16 mg/l. A discharge of liquid manure from a confined livestock operation caused a major fish kill. Pollution from septic tanks and unconfined livestock is greatest at high stream discharge when dilution reduces the impact on aquatic life.     

AN ANALYSIS OF COLIFORM BACTERIA IN THE UPPER ILLINOIS WATERWAY1

ABSTRACT: During the summer of 1971 about 150 water samples were examined for total and fecal coliform bacteria in the Upper Illinois Waterway at 19 river stations. The data per station were found to be normal geometric distributed. Bacteria densities changed with sampling dates and generally decreased with water movement downstream. Several sewage treatment effluents made marked pulses along the bacterial die-off curves. The observed fecal coliform results were evaluated in terms of the Illinois Pollution Control Board's standards. The FC:TC ratio on the waterway for each station were presented. Using Chick's Law, coliforms death rates were estimated. Efforts to correlate observed total and fecal densities with temperature, flow, algal densities, dissolved oxygen, and 5-day biochemical oxygen demand were not successful. (KEY TERMS: algae; biochemical oxygen demand; coliform bacteria; dissolved oxygen; flow; stream survey; temperature; water pollution; water quality standards)     

FECAL COLIFORM AND STREPTOCOCCUS CONCENTRATIONS IN RUNOFF FROM GRAZED PASTURES IN NORTHWEST ARKANSAS1

ABSTRACT: Agricultural practices such as cattle grazing and animal manure application can contribute to relatively high runoff concentrations of fecal coliform (FC) and fecal streptococcus (FS). Available information, however, is inconsistent with respect to the effects of such practices as well as to measures that can discriminate among candidate sources of FC and FS. The objective of this study was to assess the effects of grazing, time of year, and runoff amounts on FC and FS concentrations and to evaluate whether FCIFS concentration ratios are consistent with earlier values reported as characteristic of animal sources. Runoff from four Northwest Arkansas fields was sampled and analyzed for fecal coliform (FC) and fecal streptococcus (FS) for nearly three years (1991–1994). Each field was grazed and fertilized, with two fields receiving inorganic fertilizer and two receiving animal manure. Runoff amount had no effect on runoff concentrations of FC or FS. There were no consistent relationships between the presence of cattle and FC and FS runoff concentrations. Both FC and FS concentrations were affected by the season during which the runoff occurred. Higher concentrations were observed during warmer months. Runoff FC concentrations exceeded the primary contact standard of 200 cfu/100 mL during at least 89 percent of all runoff events and the secondary contact standard of 1000 cfu/100 mL during at least 70 percent of the events. Ratios of FC to FS concentrations varied widely (from near zero to more than 100), confirming earlier findings that FC/FS ratios are not a reliable indicator of the source of FC and FS.     

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.     

Movement of coliform bacteria and nutrients in ground water flowing through basalt and sand aquifers

Large-scale deposition of animal manure can result in contamination of surface and ground water and in potential transfer of disease-causing enteric bacteria to animals or humans. We measured total coliform bacteria (TC), fecal coliform bacteria (FC), NO3, NH4, total P, and PO4 in ground water flowing from basalt and sand aquifers, in wells into basalt and sand aquifers, in irrigation water, and in river water. Samples were collected monthly for 1 yr. Total coliform and FC numbers were always higher in irrigation water than in ground water, indicating that soil and sediment filtered most of these bacteria before they entered the aquifers. Total coliform and FC numbers in ground water were generally higher in the faster flowing basalt aquifer than in the sand aquifer, indicating that the slower flow and finer grain size may filter more TC and FC bacteria from water. At least one coliform bacterium/100 mL of water was found in ground water from both basalt and sand aquifers, indicating that ground water pumped from these aquifers is not necessarily safe for human consumption according to the American Public Health Association and the USEPA. The NO3 concentrations were usually higher in water flowing from the sand aquifer than in water flowing from the basalt aquifer or in perched water tables in the basalt aquifer. The PO4 concentrations were usually higher in water flowing from the basalt aquifer than in water flowing from the sand aquifer. The main concern is fecal contamination of these aquifers and health consequences that may arise from human consumption.     

Assessing land-use/water-quality relationships across contrasting geologic areas in New Jersey

In all, 13 stream water-quality parameters, including specific conductance (SC), pH, dissolved oxygen (DO), dissolved organic carbon (DOC), three nutrients, and six major ions were compared between the northern bedrock and southern coastal plain regions of New Jersey, USA and related to watershed-disturbance gradients characterized by the percentage of urban land, impervious surface (IS), agriculture, and altered land (sum of urban land and agriculture) in the watersheds. SC, DO, calcium, magnesium, sodium, and chloride concentrations were greater in the north. DOC was higher and pH was lower in the south. Nutrient, potassium, and sulfate concentrations did not differ between regions. Regional water-quality differences are attributed to geologic setting and land use. Except for DO in southern streams, all water-quality parameters were related to urban land, agriculture, or both. Significant correlations between urban land and IS and water-quality variables were similar in both regions with differences in unitless correlation coefficients ranging from 0.00 to 0.06. Compared to urban land and agriculture, relationships between most water-quality variables and altered land were stronger in the south. The extent of urban and agricultural lands in the watersheds did not differ by region. Altered land was correlated with urban land in both regions and with agriculture only in the south. Although focused on New Jersey, this study has broader implications for watershed planning.     

UTILIZATION OF LANDSCAPE INDICATORS TO MODEL POTENTIAL PATHOGEN IMPAIRED WATERS1

ABSTRACT: Many water bodies within the United States are contaminated by non‐point source (NPS) pollution, which is defined as those materials posing a threat to water quality arising from a number of individual sources and diffused through hydrologic processes. One such NPS pollutant that is of critical concern are pathogens derived from animal wastes, including humans. The potential presence of pathogens is identified by testing the water for fecal conform, a bacteria also associated with animal wastes. Water contaminated by animal wastes are most often associated with urban and agricultural areas, thus it is postulated that by utilizing land cover indicators, those water bodies that may be at risk of fecal coliform contamination may be identified. This study utilizes land cover information derived from the Multi‐Resolution Land Characterization (MRLC) project to analyze fecal coliform contamination in South Carolina. Also utilized are 14 digit hydro‐logic unit code (HUC) watersheds of the state, a digital elevation model, and test point data stating whether fecal coliform levels exceeded State Water Quality Standards. Proportions of the various land covers are identified within the individual watersheds and then analyzed using a logistic regression. The results reveal that watersheds with large proportions of urban land cover and agriculture on steep slopes had a very high probability of being impaired. (KEY TERMS: Geographic Information Systems; land use planning; nonpoint source pollution; statistical analysis; water quality; watershed management.)     

An Interval-Parameter Waste-Load-Allocation Model for River Water Quality Management Under Uncertainty

A simulation-based interval quadratic waste load allocation (IQWLA) model was developed for supporting river water quality management. A multi-segment simulation model was developed to generate water-quality transformation matrices and vectors under steady-state river flow conditions. The established matrices and vectors were then used to establish the water-quality constraints that were included in a water quality management model. Uncertainties associated with water quality parameters, cost functions, and environmental guidelines were described as intervals. The cost functions of wastewater treatment units were expressed in quadratic forms. A water-quality planning problem in the Changsha section of Xiangjiang River in China was used as a study case to demonstrate applicability of the proposed method. The study results demonstrated that IQWLA model could effectively communicate the interval-format uncertainties into optimization process, and generate inexact solutions that contain a spectrum of potential wastewater treatment options. Decision alternatives can be generated by adjusting different combinations of the decision variables within their solution intervals. The results are valuable for supporting local decision makers in generating cost-effective water quality management strategies.     

Models of total and presumed wildlife sources of fecal coliform bacteria in coastal ponds

Models that accurately predict fecal coliform bacteria (FCB) concentrations, one of the most widely used measures of estuarine water quality, are needed to improve land use decision-making. Rapidly occurring changes in coastal land uses and the influence on water quality increases the urgency of having improved decision tools. For this study, samples were collected monthly from six coastal ponds, two tidal creeks and four shallow water wells for up to 212 years. These data were used along with other measures of environmental conditions and land classes within each watershed to construct quantitative relationships between combinations of variables and both total and presumed wildlife sources of FCB. Linear regression, bootstrapping and generalized additive modeling that incorporates both linear and nonlinear terms were used. Results of repeated simultaneous sampling on the same tide stage of ponds and downstream estuarine creeks suggest that most FCB come from wildlife and that the ponds effectively remove these bacteria except immediately following heavy rainfall. Predictive models for concentrations of total and presumed wildlife bacteria are provided along with simple measures to estimate watershed boundaries. It is proposed that these tools can be used to minimize impacts on receiving water body quality. The models can be used to test alternative development approaches within coastal watersheds similar to that found in the southeastern USA coastal zone as well as to evaluate specific proposed landscape alterations.     

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.     

VIRGINIA USA WATER QUALITY, 1978 TO 1995: REGIONAL INTERPRETATION1

ABSTRACT: Nine surface water‐quality variables were analyzed for trend at 180 Virginia locations over the 1978 to 1995 period. Median values and seasonal Kendall's tau, a trend indicator statistic, were generated for dissolved oxygen saturation (DO), biochemical oxygen demand (BOD), pH (PH), total residue (TR), nonfilterable residue (NFR), nitrate‐nitrite nitrogen (NN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and fecal coliform (FC) at each location. Each location was assigned to one of four physiographic regions, and mean state and regional medians and taus were calculated. Widespread BOD and NFR improvements were detected and FC improvements occurred in the state's western regions. TR and TKN exhibited predominantly increasing trends at locations throughout the state. BOD, TKN, NFR, and TR medians were higher at coastal locations than in other regions. NN, TKN, and TR exhibited predominantly increasing trends in regions with high median concentrations, while declining trends predominated in regions with relatively high BOD, FC, and NFR medians. Appalachian locations exhibited the greatest regional water‐quality improvements for BOD, FC, NFR, and TKN. Factors responsible for regional differences appear to include geology, land use, and landscape features; these factors vary regionally.     

AN EVALUATION OF THE AVAILABLE TECHNIQUES FOR ESTIMATING MISSING FECAL COLIFORM DATA1

ABSTRACT: This paper presents the findings of a study aimed at evaluating the available techniques for estimating missing fecal coliform (FC) data on a temporal basis. The techniques investigated include: linear and nonlinear regression analysis and interpolation functions, and the use of artificial neural networks (ANNs). In all, seven interpolation, two regression, and one ANN model structures were investigated. This paper also investigates the validity of a hypothesis that estimating missing FC data by developing different models using different data corresponding to different dynamics associated with different trends in the FC data may result in a better model performance. The FC data (counts/100 ml) derived from the North Fork of the Kentucky River in Kentucky were employed to calibrate and validate various models. The performance of various models was evaluated using a wide variety of standard statistical measures. The results obtained in this study are able to demonstrate that the ANNs can be preferred over the conventional techniques in estimating missing FC data in a watershed. The regression technique was not found suitable in estimating missing FC data on a temporal basis. Further, it has been found that it is possible to achieve a better model performance by first decomposing the whole data set into different categories corresponding to different dynamics and then developing separate models for separate categories rather than developing a single model for the composite data set.     

FECAL COLIFORM SOURCE ASSESSMENT IN A SMALL,MIXED LAND USE WATERSHED1

ABSTRACT: This study presents the results of fecal coliform (FC) sampling in the Rawls Creek, South Carolina, watershed during 1999 and 2000. The work was undertaken because the watershed is listed on the 303(d) list for South Carolina due to FC excursions. The watershed is 43.8 percent residential, 35 percent forest, 5.7 percent mixed urban, 4.9 percent commercial, and 4.8 percent agriculture. Samples were taken at 15 stations during eight field trips divided into two phases to characterize FC inputs from subbasins and to integrate results from upstream sampling. FC concentrations ranged from 135 to 730 colonies/100 ml. Results suggest that retention ponds in the area are a significant factor in attenuation of FC concentrations. Catchments with the largest contiguous impervious areas are the greatest source of FC. The highest concentrations of FC were observed at stations just downstream from a large detention basin that intercepts storm runoff from a large commercial area. Further analysis of the design and performance of that structure is suggested. The Koon Branch tributary is less than 20 percent of the land area in the watershed but may contribute 40 percent of the fecal loading. The results of this study confirm the importance of site assessments to aid understanding of nonpoint source pollution in complex watersheds.     

AGRICULTURAL LAND USE IMPACTS ON BACTERIAL WATER QUALITY IN A KARST GROUNDWATER AQUIFER1

ABSTRACT: The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian Region. Karst areas comprise about 18 percent of the Region's land area. An estimated one-third of the Region's farms, cattle, and agricultural market value are on karst terrain. The purpose of this study was to compare fecal bacteria densities in karst groundwater impacted by two primary agricultural land uses in central Appalachia. Fecal bacteria densities were measured in cave streams draining two primary land management areas. The first area was pasture serving a beef cow-calf operation. The second area was a dairy. Neither area had best management practices in place for controlling animal wastes. Median fecal coliform and fecal streptococcus densities were highest in cave streams draining the dairy. Median fecal coliform densities in the dairy-impacted stream were greater than 4,000 CFU/100 ml and the median fecal coliform densities in the pasture-impacted streams were less than 10 CFU/100 ml. Median fecal streptococcus densities in the same streams were greater than 2,000 CFU/100 ml and 32 CFU/100 nil, respectively. A second dairy, with best management practices for control of animal and milkhouse waste, did not appear to be contributing significant amounts of fecal bacteria to the karst aquifer. It was concluded that agriculture was affecting bacterial densities in the karst aquifer. New management practices specifically designed to protect karst groundwater resources may be one way to protect the groundwater resource.     

Treatment of domestic wastewater using an anaerobic baffled reactor followed by a duckweed pond for agricultural purposes

The treatment and reuse of domestic wastewater using an anaerobic baffled reactor (ABR) followed by a duckweed pond (DWP) were the main theme of the present study. The ABR was fed continuously with domestic wastewater at four HRTs ranging from 8 to 24 h and corresponds to organic loading rates ranging from 0.67 to 2.1 kg COD/m³/day. The ABR effluent was fed to a DWP operating at 10 and 15 days. The performance of the ABR at the four HRTs gave satisfactory results. Chemical oxygen demand (COD) removal was between 68 and 82%. Fecal coliform removal was between 1 to 2 logs. The 12- and 18-h hydraulic retention times (HRTs) gave close results, as indication of the possible selection of the 12-h HRT as the optimum operation for the ABR based on economic advantage. The ABR compartmentalized structure gave results higher than those produced by the one-stage digester and similar to those produced by the two-phase anaerobic digestion process. Duckweed ponds as post-treatment operated at 10 days and 15 days gave the best results at 15-day HRT, where it was possible to remove 73.4% of nitrogen and 65% of phosphorus and produce protein-rich dry duckweed of 105 kg/ha/day on average. The removal of fecal coliform (FC) in duckweed ponds was 3–4 logs. The final treated domestic sewage characteristics proved its compliance with the Egyptian standards for reuse in restricted irrigation.     

Bacterial water quality: Springs and streams in the Great Smoky Mountains National Park

Water samples from streams and springs in the Great Smoky Mountains National Park were analyzed for fecal coliform, fecal streptococcus, and total coliform bacteria. Levels of bacteria were found to be highly variable but related to elevation, time of year, type of water source, and water level of the streams. Visitors did not seem to be major contributors to bacterial contamination. Levels of fecal coliform and total coliform in most water samples were unsuitable for drinking without treatment. Tennessee state standards for body contact recreation (swimming and wading) were exceeded in a few samples but none from streams suitable for swimming. As a result of these findings, park managers increased efforts to inform visitors of the need to treat drinking water and removed improvements at backcountry springs which tended to give the springs the image of safe, maintained water sources.     

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.     

MODELING FECAL COLIFORM CONTAMINATION IN THE RIO GRANDE1

This study examines sources of fecal coliform in Segment 2302 of the Rio Grande, located south of the International Falcon Reservoir in southern Texas. The watershed is unique because the contributing drainage areas lie in Texas and Mexico. Additionally, the watershed is mostly rural, with populated communities known as “colonias.” The colonias lack sewered systems and discharge sanitary water directly to the ground surface, thus posing an increased health hazard from coliform bacteria. Monitoring data confirm that Segment 2302 is not safe for contact recreation due to elevated fecal coliform levels. The goal of the study was to simulate the observed exceedences in Segment 2302 and evaluate potential strategies for their elimination. Fecal coliform contributions from ranching and colonia discharges were modeled using the Hydrologic Simulation Program‐Fortran (HSPF). Model results indicated that the regulatory 30‐day geometric mean fecal coliform concentration of 200 colony forming units (cfu) per 100 milliliters is exceeded approximately three times per year for a total of 30 days. Ongoing initiatives to improve wastewater facilities will reduce this to approximately once per year for 14 days. Best management practices will be necessary to reduce cattle access to streams and eliminate all exceedences. The developed model was limited by the relatively sparse flow and fecal coliform data.     

Fecal coliform loadings and stocks in buttermilk bay,Massachusetts, USA,and management implications

Abundance of fecal caliform bacteria is a weak index of the presence of human pathogens in wastewater entering coastal waters. In spite of this, use of fecal caliform indices for management purposes is widespread. To gain insight into interpretation of fecal coliform data, we evaluated size of stocks of fecal coliforms in water, sediments, and sea wrack, in Buttermilk Bay, a coastal embayment in Massachusetts. Sediments contained most of the fecal coliforms. Fecal coliforms in sediments were as much as one order of magnitude more abundant than in the water column or in sea wrack. The fecal coliforms in sediments of Buttermilk Bay were so abundant that resuspension of fecal coliforms from just the top 2 cm of muddy sediments could add sufficient cells to the water column to have the whole bay exceed the federal limit of fecal coliforms for shellfishing. The major sources of fecal coliforms to the bay were water-fowls, surface runoff, groundwater, and streams. Waterfowl were the largest source of fecal coliforms during cold months; surface runoff, streams, and groundwater were most important during warm months. Redirection of surface runoff pipes is unlikely to be a very successful management action since contributions via this source are insufficient to account for the measured increases in concentrations of fecal coliforms in water. Removal of waterfowl is also unlikely to be useful, since fecal coliform concentrations leading to closures of shellfish beds and swimming areas are most frequent during warm months when waterfowl are rarest. Rates of loss of fecal caliform cells from the water column by death and tidal exchange were high. Mortality of cells was about an order of magnitude larger than losses by tidal exchange. The amounts of fecal coliforms brought into the bay by waterfowl, surface runoff, groundwater, and streams are an order of magnitude smaller than the losses by mortality and tidal removal. This implies that there is an additional source of fecal coliforms within the bay. We suggest that resuspension of the upper layers of sediments can easily account for the fecal coliforms present in the water. Fecal coliform content of water and shellfish were not correlated. In contrast, sediment and shellfish fecal coliform abundances were significantly related. Monitoring of fecal coliforms in sediments may provide a better assessment of shellfish than sampling of water. The large fecal coliform stock in sediments should be the first priority for management. Efforts ought to be directed toward the reduction of sediment fecal coliform stocks. Lowering nutrient additions to coastal water bodies may be one practical approach.     

AN ANALYSIS OF SEASONAL FECAL COLIFORM LEVELS IN THE TCHEFUNCTE RWER1

ABSTRACT: A model for estimating seasonal fecal coliform concentrations in the Tchefuncte River as a function of river discharge was developed. Data on fecal coliform concentration were obtained from the Louisiana Department of Health and Hospitals and were available for a period of 15 years (1975 through 1992) from three locations. Stream flow data were obtained from a gaging station of the U. S. Geological Survey at Folsom, Louisiana. These data were available for 49 years (1943 through 1991). The climate of the area is characterized by different precipitation/runoff mechanisms for the summer and winter seasons. The division for seasons used in this analysis was May through October (summer season), and November through April (winter season). Because of the combined effects of climatic mechanisms causing precipitation and the seasonal variation of evapotranspiration, runoff is greater in the winter season resulting in higher fecal coliform counts in the Tchefuncte River. Statistical analysis revealed a statistically significant relationship between fecal coliform concentration and discharge for each season, at each of three sites on the Tchefuncte River.