Coliform Concentrations Research Articles

A predictive model of the impact of urbanization on bacterial loads in watersheds

Bacterial concentration is one of the most important aspects of water quality. Many regions in the world are affected by increasing urbanization and a potential increase in bacterial concentrations in waters. We used long-term data from 68 stations in eight watersheds in Eastern Thailand to quantify the temporal and geographical variation in total and fecal coliform bacteria. Descriptive statistics showed considerable seasonal, inter-annual, and geographical variation. In order to quantify this multi-level variation, we built a predictive model of bacterial loads. Using fixed- and mixed-effects regression models, we built a model including the effects of urbanization and other significant variables. The best model, fitted by restricted maximum likelihood, included the effects of season, year, urbanization as fixed effects, and of watershed and station as nested, random effects. Temporal variation was related to seasonal and annual variations. Spatial variation had a very significant impact on the bacterial concentrations. Urbanization was an important factor controlling concentrations of bacteria in rivers: we found that the proportion of urban area around a station had a statistically significant effect on log-transformed total coliform bacterial concentration with a slope equal to 1.3 (SE = 0.3), and on log-transformed fecal coliform bacterial concentration with a slope equal to 1.4 (SE = 0.3). Our model predicts that bacterial concentrations would be multiplied by 20 if land is transformed from non-urban to fully urban.

Series Type Vertical Subsurface Flow Constructed Wetlands for Dairy Farm Wastewater Treatment

Agricultural and livestock farms are the major sources of freshwater pollution in rural areas in the Philippines. Small and unregulated dairy farms operate without appropriate wastewater treatment before discharge because it is too expensive to do so. With this scenario, the emergence of the need for a sustainable and cheaper alternative for wastewater treatment gave rise to the research and development studies of the efficiency of constructed wetlands. The study aims to analyze the treatment efficiency of series type vertical subsurface flow constructed wetlands planted with Napier Grass (Pennisetum Purpureum Schumach) on University of the Philippines Los Baños (UPLB) Dairy Farm wastewater with a focus on fecal coliform concentration, electric conductivity, total dissolved solids content, nitrite and nitrate concentration and pH level. The study showed that after treatment using the vertical subsurface flow constructed wetlands, all the parameters except the fecal coliform concentration were below the standard limits set by the Department of Agriculture with average removal efficiencies of 12.94% on Electric Conductivity (EC), 12.86% on Total Dissolved Solids (TDS), 216.44% on Nitrite (NO2-N), -125.64% on Nitrate (NO3-N), and -25.64% on Fecal Coliforms (FC). With the results of the analysis, a design of series type vertical subsurface flow constructed wetland for dairy farm wastewater treatment is suggested. Doi: 10.28991/cej-2021-03091654 Full Text: PDF

Study of three domestic sewage submarine outfall plumes through the use of numerical modeling in the São Sebastião channel, São Paulo state, Brazil

The dispersion of the thermotolerant coliform plumes emitted from the Araçá, Itaquanduba and Cigarras domestic sewage submarine outfalls in the São Sebastião Channel was modeled. The plumes were simulated as the only pollution sources considering bacterial decay for the summer and winter of 2016. The main goal was to determine if and which areas were impacted by the disposal systems. The simulated concentrations were quantitatively compared with Enterococcus and thermotolerant coliform data provided by sanitation agencies in São Paulo state (CETESB and SABESP). The UM3 model from Visual Plumes software and the ECOM were used as the near-field and far-field models, respectively. The ECOM was configurated with 37 sigma levels and its horizontal resolution varies from 0.2 km to 5 km. The modeled concentrations did not exceed the limit stated by CONAMA Resolution 274 (2000), with the exception of that in June 2016. The main conclusion of this study is that channel hydrodynamic patterns are sufficient to disperse the plumes from sewage disposal outfalls. The areas adjacent to Araçá outfall presented the highest persistence of coliform concentrations; however, the modeled concentrations did not exceed 1000 MPN/100 mL for more than 0.1% of the time. The simulations satisfactorily reproduced the coliform variability and dispersion in the region.

Detection Of Fecal Coliforms In Water Used In Formal And Informal Food Outlets In Kasungu District, Malawi

Poor sanitary practices are common amongst many food handlers posing a health risk to consumers. Maintenance of high quality water is one of the most important aspects of ensuring consumer safety. Therefore, regular water testing is critical in public food outlets where bacterial contamination may cause outbreak of disease. The study aimed at analyzing water samples obtained from the formal and informal food outlets for the presence of fecal coliforms that are indicative of poor sanitation that result in foodborne infections amongst consumers. Using a cross-sectional design, water samples from participating food outlets (N=40) were analyzed using the membrane filtration method. Samples were filtered, under vacuum, through a cellulose acetate membrane of 0.45 μm pore size. Fecal coliforms exceeding permissible range were detected in 15 test samples (N=40). The median (IQR) concentrations of fecal coliforms (FC/100ml) in dishwashing water was 1(136) and 145(340) for the formal and informal food outlets respectively. The median (IQR) for drinking water was 0(0) with a minimum and maximum range of 0 and 14 FC/100mls. The study established a positive correlation between fecal coliforms and electrical conductivity, and total dissolved solids (p<0.05) in dish washing water used at both formal and informal food outlets. Contamination was attributed to lack of running water, poor pest control and unwholesome practices in many food outlets. Based on the study findings, it is concluded that electrical conductivity, total dissolved solids and turbidity values may be used to deduce the presence of fecal coliforms in water. The study recommends that water drawn from unprotected sources must be boiled or treated at the point of use before it can be safely used in food outlets. Periodic water testing and sanitary supervisions for all food outlets must be mandatory to ensure compliance with minimum set standards.

Combined AOP/GAC/AOP systems for secondary effluent polishing: Optimization, toxicity and disinfection

This study reports the use of advanced oxidation processes (AOPs), specifically O3, O3/H2O2 and UV/H2O2, in combination with granular activated carbon (GAC) to polish secondary effluents. For this purpose, three configurations were tested: O3-GAC-O3, O3/H2O2-GAC-O3/H2O2 and UV/H2O2-GAC-UV/H2O2. The efficiency evaluation was based on the ability of the systems to remove aromaticity (UV254), organic matter (chemical oxygen demand - COD), Escherichia coli and total coliforms content as well as toxicity (Artemia salina and Allium cepa). The methods were optimized using central composite design to investigate the influence of O3 and H2O2 concentration in the efficiency of the system and the optimal conditions were subsequently applied to treat urban secondary effluents. High organic matter removal rates were obtained by all the tested configurations, of which O3-GAC-O3 proved to be the most efficient. The systems were also efficient to disinfect the samples, promoting nearby 5-log reduction of E. coli and total coliforms. Acute toxicity, cytotoxicity, and genotoxicity were observed in samples subjected to the UV/H2O2-GAC-UV/H2O2 method. When used alone, GAC removed around 80% of organic matter, nevertheless failed to disinfect the samples, which furthermore exhibited acute toxicity and genotoxicity toward A. cepa. Samples subjected to direct photolysis proved more toxic than untreated samples while uncombined H2O2, O3, GAC, and UV, as well as O3/H2O2 and UV/H2O2 failed to degrade organic matter or to mitigate the toxicity of the samples.

An inverse approach to estimate bacterial loading into an estuary by using field observations and residence time

Pathogen, whose abundance is often measured by the concentration of fecal indicator bacteria, is listed as the top cause of waterbody impairments in the US. An accurate estimation of the bacterial loading from watershed is thus fundamentally important for water quality management. Despite advances in watershed modeling, accurate estimation of bacterial load is still very challenging due to large uncertainties associated with bacterial sources, accumulation, and removal in the watershed. We introduce an inverse method using field-measured bacterial concentrations and numerical model-calculated residence time to estimate the bacterial loading from the drainage basin. In this method, an estuary is divided into multiple segments. Water and bacterial fluxes between neighboring segments are computed from a set of linear equations derived based on mass balance equation and the relationship between residence time and water fluxes. Loading to each segment can then be estimated by combining the computed water fluxes and observed bacterial concentrations. The approach accounts for seasonal and interannual variations in hydrodynamics due to tide, river discharge, and estuarine circulations. The method was applied to Nassawadox Creek, a sub-estuary of Chesapeake Bay, where Fecal Coliform concentrations at 46 stations were continuously monitored. The method is verified by the high consistency between estimated loadings and presumably known input loadings in numerical experiments with either constant or time-varying input loadings. With sparse observational data, the inversely estimated loadings agree well with the loadings from a previously calibrated watershed model, demonstrating the reliability of the method. The inverse approach can be used to cross-check the result of watershed models and assess changes in watershed condition. The method is also readily applicable to other types of materials, such as inorganic nutrients.

Stormwater quality assessment and management for the town of Jasper in Alberta, Canada

Abstract Stormwater pollutants can have deleterious impacts on the aquatic life of receiving water bodies. This paper presents the findings of a stormwater quality monitoring program performed in the town of Jasper in Alberta, Canada. This is one of the very few studies done on a small urban settlement to identify key pollutants of concern, characterize stormwater and identify unique pollutant sources in the town. A total of 14 stormwater quality parameters were found to be of high concern to aquatic life. The most prominent pollutants were total suspended solids (TSS), metals and phosphorus which compared well with studies conducted in large urban settlements. Tourist influx contributed to high metal and petroleum hydrocarbon loads during the peak season due to high vehicular activity. Elk were found to reside in the town during summer and their fecal droppings resulted in elevated fecal coliform concentrations. It was found that winter road salting was responsible for excessive chloride concentrations observed during the spring melt. TSS concentrations were statistically correlated with various metals as well as phosphorus using Spearman's rank correlation. It was found that the current street sweeping schedule in the town coincided with lower TSS and metal loads in stormwater.

Effects of the lack of basic public sanitation on the water quality of the Caeté River estuary in northern Brazil

The present study investigated the evolution of the contamination of the estuary of the Caeté River by thermotolerant coliforms over the past decade. The hypothesis tested was that the conditions of the Caeté estuary have worsened over this period due to a combination of population growth and the lack of investment in public sanitation by the local authorities. Samples for hydrological and microbiological analysis were collected at eight sample points in 2013, 2014, 2018, and 2019. The upper sector of the estuary was represented by the samples from P1–P4. This sector is the most urbanized, and the most affected by human activities, with 100% of the samples collected presenting thermotolerant coliform concentrations of over 1,100 MPN 100 mL−1. Conditions were also considered to be “inappropriate” for human use in other areas at certain times of year. Despite being located within a protected area, the implementation of a public sanitation system, proposed in the master plan of the municipality of Bragança almost two decades ago, has yet to be initiated. Compared with the results of previous studies of the Caeté estuary, more than a decade ago, the contamination of the water has increased considerably. Based on the criteria of the current Brazilian legislation, all types of human use of the water are compromised, although socioeconomic activities continue as normal. This situation may eventually impact the health of the local population and affect economic activities. The conditions found in the Caeté estuary appear to be typical of other coastal Amazonian municipalities.

Cranberry (<i>Vaccinium macrocarpon</i>) dietary supplementation and fecal microbiota of Wistar rats

Cranberry (Vaccinium macrocarpon) dietary supplementation can help prevention of urinary tract infections through the supply of proanthocyanidin-type polyphenols (PAC). The main uropathogenic bacteria are members of the intestinal microbiota. A randomized cross-over experiment was done to investigate whether cranberry dietary supplementation affects concentrations of thermotolerant coliforms, Enterococcus spp. and Lactobacillus spp. in rat faeces. Thirteen rats, housed in individual cages, received successively two diets as pellets during 7 days each: a standard diet without polyphenols and the standard diet supplemented with cranberry powder containing 10.9 mg/100 g of PAC. There was a 7 days wash-out period in between with standard diet without polyphenols. Body weight and feed intake were recorded. Faeces were collected on the last day of treatment, and crushed to count the different bacterial populations using the most probable number method. Thermotolerant coliforms were grown in BGBLB tubes and on MacConkey agar. Enterococcus spp. were grown in Rothe and Litsky broths and on KF Streptococcus agar. Lactobacillus spp. were grown in Man Rogosa Sharpe broth. Body mass gains were not affected by cranberry supplementation. This is consistent with equal food intake, cranberry powder not providing significant energy supplement. Cranberry dietary supplementation was associated with changes in fecal concentrations of thermotolerant coliforms, and Enterococcus spp. in some rats, but did not induce significant changes in bacterial fecal concentrations in a global population of 13 rats. In conclusion, we did not observe any significant effect of dietary cranberry supplementation on the fecal microbiota of Wistars rats for a 7-day diet.

Microbiological Profile, Incidence, and Behavior of Salmonella on Seeds Traded in Mexican Markets

Consumption of seeds has increased in recent years due to their high nutrient content. However, Salmonella outbreaks associated with the consumption of low-water-activity food items have also increased, although these food items do not support microbial growth. The main goal of this study was to quantify microbial indicators and to determine the prevalence and content of Salmonella in chia, amaranth, and sesame seeds obtained from Mexican retail outlets. In addition, the behavior of this pathogen on seeds was evaluated. One hundred samples of each product (chia, amaranth, and sesame seeds) were collected from Queretaro City markets. Aerobic plate count, coliforms, and Escherichia coli bacteria were quantified, and the presence and number of Salmonella pathogens were also determined. Chia, amaranth, and sesame seeds (1 kg each) were inoculated with a cocktail of five Salmonella strains (∼6 log CFU mL-1) and stored at ambient temperature, and then populations of Salmonella were quantified. The median aerobic plate count contents in chia, amaranth, and sesame seeds were 2.1, 2.4, and 3.8 log CFU g-1, respectively, and the content of coliforms on the seeds ranged from 0.48 to 0.56 log most probable number (MPN) per g. E. coli was present at low concentrations in the three types of seeds. Salmonella was detected in chia (31%), amaranth (15%), and sesame (12%) seeds, and the population ranged from 0.48 to 0.56 log MPN g-1. Salmonella levels decreased through 240 days of storage, showing inactivation rates of 0.017, 0.011, and 0.016 log CFU h-1 in chia, amaranth, and sesame seeds, respectively. The high prevalence of Salmonella in the seeds highlights potential risks for consumers, particularly given that seeds are generally consumed without treatments guaranteeing pathogen inactivation.

Microbiological status of drinking water sources and its relationship with human health in Solan, India.

In Solan district, the developmental activities associated with chemical based farming, rapid urbanization, and rampant industrialization have led to many diarrhoeal, gastroenteritis, and hepatitis disease outbreaks. This has necessitated for microbiological assessment of indicator organisms, the thermotolerant coliforms, in drinking water sources, and their relationship with diarrhoeal disease. All the 49 Public Health Institutes (PHIs) of the district were categorized into very low, low, moderate, and high disease burden regions by stratification method. For drinking water, 55.5, 16.5, and 17% people preferred springs, borewells, and hand-pump respectively. These sources inventoried by Knowledge, Attitude, and Practice survey in one of very low and seven of high disease burden regions, and were analyzed by multiple tube fermentation technique. A cross-sectional survey of 200 children was undertaken for diarrhoeal disease estimation. Parwanoo, an industrial and Kurgal, a non industrial region witnessed highest (30.20) and lowest (4.40) Most Probable Number (MPN) per 100 ml water of thermotolerant coliforms, respectively. Thermotolerant coliforms were also observed significantly more (16.77 MPN/100 ml water) in monsoon than in post monsoon season (9.04 MPN per 100 ml water). The thermotolerant coliform Escherichia coli was recovered from six and three water sources respectively during monsoon and post monsoon. A strong correlation (r = 0.78) existed between the diarrhoeal disease occurrence and the concentration of thermotolerant coliforms in monsoon whereas it was moderate (r = 0.61) in post monsoon. The study indicated more contamination of water sources due to industrial activities which further got aggravated during the rainy season of the region.

Neural network and cubist algorithms to predict fecal coliform content in treated wastewater by multi-soil-layering system for potential reuse.

This study aims to find the most accurate machine learning algorithms as compared to linear regression for prediction of fecal coliform (FC) concentration in the effluent of a multi-soil-layering (MSL) system and to identify the input variables affecting FC removal from domestic wastewater. The effluent quality of two different designs of the MSL system was evaluated and compared for several parameters for potential reuse in agriculture. The first system consisted of a single-stage MSL (MSL-SS), and the second system consisted of a two-stage MSL (MSL-TS). The concentration of FC in the effluent of the MSL-TS system was estimated by three machine learning algorithms: artificial neural network (ANN), Cubist, and multiple linear regression (MLR). The accuracy of the models was measured by comparing the real and predicted values. Significant (p<.001) improvements were noted for the removal of pollutants by the MSL-TS system compared with the MSL-SS system. Overall, the water quality parameters investigated complied with FAO irrigation standards. The predictive performance of the models has been compared and evaluated using several metrics. The results revealed that the ANN model yielded a superior predictive performance (R2 =.953), followed by the Cubist model (R2 =.946) and the MLR technique (R2 =.481). Based on the accurate model (ANN), the degree of influence of each predictor was investigated, and the results show that total suspended solids and pH have proved to be more useful for predicting FC concentrations.

Total and faecal coliforms presence in cenotes of Cancun; Quintana Roo, Mexico

The large increase in population in Cancun, Mexico has increased domestic, agricultural and industrial activities, resulting in inadequate solid and liquid waste management that can affect underground aquifers. One of the factors which affects water quality is coliform bacteria. The present study focused on determining the presence of total and faecal coliforms in ten urban cenotes in Cancun. Sampling was carried out in the dry and rainy seasons of 2018. The Most Probable Number (MPN) technique was used to determine the concentration of coliform bacteria. The results from the analyses indicate that the ten cenotes are contaminated with total and faecal coliforms. Additionally, the concentration of coliforms increases during the rainy season. We conclude that all the cenotes are contaminated with faecal coliforms and suggest that more studies are necessary to determine the origin of this contamination and the impact on the ecosystem.

The Influence of Non-Engineered Municipal Landfills on Groundwater Chemistry and Quality in Bloemfontein, South Africa.

This study assessed the groundwater quality around two municipal solid waste landfill sites, in the city of Bloemfontein, Free State Province, South Africa. The two landfill sites are located in two contrasting geological terrains, with both lacking some basic facilities found in a well-designed landfill. A total of eight groundwater samples were collected from pollution monitoring boreholes near the two landfill sites, with five samples representing the northern landfill site and three samples representing the southern landfill site. The samples were collected in the autumn and winter seasons to assess any possible seasonal variations. They were analysed for physicochemical (pH, electrical conductivity (EC), total dissolve solids (TDS), chemical oxygen demand (COD) and total organic carbon (TOC)) and microbiological parameters (Escherichia coli, total coliform). The results of the analysis showed that the waters from both landfills were generally dominated by Ca, Mg, SO4, and HCO3 ions. Some of the major anions and cations in the water samples were above the South African National Standard (SANS241:2015) and World Health Organisation (WHO) permissible limits for drinking water. Majority of the boreholes had total dissolved solids and electrical conductivity values exceeding the SANS 241:2015 and WHO permissible limits. Piper trilinear plots for the two landfill sites showed that Ca(Mg)HCO3 water type predominates, but Ca(Mg)SO4 and Ca(Mg)Cl were also found. These water types were further confirmed with expanded Durov diagrams, indicating that that the boreholes represented a water type that is seldom found which is undergoing ion exchange, typical of sulphate contamination. From the SAR diagrams, boreholes in the northern landfill site had a high salinity hazard with only one borehole in the southern landfill site having a high salinity hazard. The geology was found to play a significant role in the distribution of contaminants into the groundwater systems in the study area. The study concluded that the northern landfill site had a poorer water quality in comparison to the southern landfill site based on the analysed physicochemical parameters. However, the southern landfill site showed significant microbial contamination, due to the elevated amount of E. coli and total coliform concentrations. The high permeability of the weathered dolerites in the northern landfill site might have enabled the percolation of contaminants into the groundwater resulting in the poorer water quality.

A Multivariate and Spatiotemporal Analysis of Water Quality in Code River, Indonesia.

The efficacy of a water quality management strategy highly depends on the analysis of water quality data, which must be intensively analyzed from both spatial and temporal perspectives. This study aims to analyze spatial and temporal trends in water quality in Code River in Indonesia and correlate these with land use and land cover changes over a particular period. Water quality data consisting of 15 parameters and Landsat image data taken from 2011 to 2017 were collected and analyzed. We found that the concentrations of total dissolved solid, nitrite, nitrate, and zinc had increasing trends from upstream to downstream over time, whereas concentrations of parameter biological oxygen demand, cuprum, and fecal coliform consistently undermined water quality standards. This study also found that the proportion of natural vegetation land cover had a positive correlation with the quality of Code River's water, whereas agricultural land and built-up areas were the most sensitive to water pollution in the river. Moreover, the principal component analysis of water quality data suggested that organic matter, metals, and domestic wastewater were the most important factors for explaining the total variability of water quality in Code River. This study demonstrates the application of a GIS-based multivariate analysis to the interpretation of water quality monitoring data, which could aid watershed stakeholders in developing data-driven intervention strategies for improving the water quality in rivers and streams.

EVALUACIÓN DE CONTAMINACIÓN MICROBIOLOGICA ANTROPOGÉNICA EN AGUA DE MAR DE LA BAHÍA DE CARTAGENA-BOLÍVAR DURANTE ABRIL A JULIO DE 2019

Durante abril a julio del 2019, se llevó a cabo un monitoreo donde se evaluó la calidad del agua en 26 estaciones distribuidas en tres sectores de la bahía de Cartagena (Bahía Externa, Interna y sector Isla Manzanillo). Se establecieron los niveles y las fuentes de contaminación en cada estación. Se encontró que parámetros fisicoquímicos como el pH, la temperatura, la salinidad, el oxígeno disuelto y turbidez, están dentro de los intervalos exigidos por la norma y son aptos para aguas marinas con uso recreativo de contacto primario. Para los parámetros microbiológicos (Coliformes totales, Enterococcus spp, E.coli) se encontró que la Bahía interna y la Isla Manzanillo son los sectores que tienden a tener mayor concentración microbiana de coliformes totales. La Isla Manzanillo es el sector donde hubo presencia de todos los indicadores microbiológicos y, mayor presencia de Enterococcus spp. Mientras que en la Bahía Externa se observa mayor concentración de E. coli. También se evidencia que en temporada de lluvia aumenta la concentración microbiana. Como conclusión la bahía permanece bajo la influencia de caños, aguas negras y continua siendo alimentada con heces humanas y de animales de sangre caliente.

Design of a cost-effective electrochlorination system for point-of-use water treatment

Bacteriological contamination in drinking water is known to be responsible for the spread of various waterborne diseases. Although chlorine is frequently used as disinfectant in water treatment, low-cost disinfecting technologies in the villages of developing and under-developed countries are not yet successfully implemented. This study contributed in designing a simple and inexpensive water disinfection unit to produce chlorine from the naturally available dissolved chloride of groundwater by electrochlorination, using inert and cheap graphite electrodes. Laboratory-based experiments were performed in both batch and continuous flow reactors to study the effect of time, current, electro charge loading (ECL), and surface area of electrodes in chlorine generation and bacterial inactivation. Controlled experiments in continuous mode in the absence of chlorine further indicated the possibility of partial inactivation of bacteria under the influence of the electric field. Finally, a treatment unit with drilled anodes, and undrilled cathode electrodes, in continuous flow set-up was installed in four schools of four different villages in West Bengal, India. An average residual chlorine concentration and removal efficiency of total coliform in the designed systems were determined as 0.3 ± 0.07 mg/L, and 98.4% ± 1.6%, respectively.

Hygienic Condition of Different Water Sources in the Kharaa River Basin, Mongolia in the Light of a Rapid Warming Trend

Mongolia is a water-scarce land-locked country, and available water resources are utilized for multiple purposes including irrigation, food preparation, drinking water for livestock and people. Limited data availability on water hygiene means that the related risks to public health are only partially understood. This is particularly problematic due to the widespread use of unimproved water sources such as surface water and water from simple shallow wells. Based on two field surveys in the Kharaa River Basin in spring 2017 and 2018, we assessed the presence and quantity of total coliforms (TC), fecal coliforms (FC), and E. coli bacteria in surface waters and wells and investigated potential linkages between temperature and hygiene. In the Kharaa River and its tributaries, TC concentrations averaged at a most probable number of (MPN) of 754 ± 761 per 100 mL and FC concentrations at an MPN of 31 ± 33. Only small and non-significant correlations between coliform concentrations and temperature were identified. Coliforms concentrations in wells were lower (average MPN for TC: 550 ± 1286, and for FC 58 ± 253). There was considerable variation between wells, with moderate but significant correlations between temperature and bacterial counts. Low water temperatures in April and May (just above freezing to less than 6.5 °C in wells and 7.5 °C to 14.5 °C in the river system) and the positive correlations between temperature and coliform concentrations particularly for well samples indicate that further warming is likely to increase the risks of microbiological water pollution. In the future, this should be complemented by modeling at a watershed scale. This should include the consideration of a trend towards stronger rainfall events, changes in livestock density, and urban sewage treatment and discharge, which are other likely drivers of changes in water hygiene.

Evaluation of a multivariate analysis modeling approach identifying sources and patterns of nonpoint fecal pollution in a mixed use watershed

Surface waters listed on impaired waters (303 d) lists due to pathogen contamination pose a significant environmental and public health burden. The need to address impairments through the Total Maximum Daily Load (TMDL) process has resulted in method developments that successfully identify nonpoint fecal pollution sources by maximizing available resources to improve water quality. However, the ability of those methods to effectively and universally identify sources of fecal pollution requires further evaluation. The objective of this research was to assess the usefulness of a previously described multivariate statistical approach to identify common patterns influencing fate and transport of fecal pollutants from sources to receiving streams using the Tuckasegee River watershed in Western North Carolina as a test watershed. Two streams were routinely monitored using a targeted sampling approach to assess fecal pollution extent and identify nonpoint sources using canonical correlation and canonical discriminant analyses. Fecal pollution in the watershed varied spatially and temporally with significantly higher fecal coliform concentrations observed in Scott Creek (f = 9.49, p = 0.002) and during the summer months (f = 14.8, p < 0.0001). Canonical correlations described 62–67% of water quality variability and indicate that fecal pollution in portions of the watershed are influenced by stormwater runoff and fecal indicator bacteria resuspension from sediment, while fecal pollution in other portions are influenced by soil erosion and surface runoff. Canonical discriminant analyses indicate that LULC significantly influences the nature and extent of fecal pollution. These results demonstrate that chemical parameters are useful predictors of fecal pollution and can help identify nonpoint fecal pollution sources in relation to land use patterns and land management practices. This approach to water quality monitoring program design and data analysis may effectively and efficiently identify parameters that best predict fecal pollution to aid in development and implementation of effective TMDLs to remediate impaired waters.

GIP-SWMM: A new Green Infrastructure Placement Tool coupled with SWMM

A new Green Infrastructure Placement Tool coupled with Storm Water Management Model (GIP-SWMM) is developed for selection and strategic placement of Green Infrastructure (GI) practices. The tool supports GI placement at multiple scales - from a few city blocks to large watersheds. GI is a multi-benefit option for stormwater management and can revitalize communities while reducing sewage overflows and improving runoff quality. However, cost-effective planning and placement of GI to achieve management goals remains a challenge and requires an integrated watershed approach. An optimization approach was developed coupled with the SWMM to find optimal combination and placement of GI to meet target flow and pollutant load reduction while minimizing cost at a watershed scale. The tool includes 13 GI types and selection and placement of GI within a watershed is based on their capital cost and effectiveness. The tool generates cost-effectiveness curves (cost vs size of GIs) for discharge and pollutants. GIP-SWMM provides a means for objective analysis of managing alternatives among multiple interacting and competing options. The desired outcome from the system application is a thorough, practical, and informative assessment considering economic, and engineering factors. The performance of the tool was evaluated in the Meade-Hawthorne drainage basin in Rapid City, South Dakota. GI placement options were assessed for multiple target levels for discharge, TSS, E coli, and Fecal coliform. Cost-effectiveness curves were developed for discharge, TSS, E coli, and Fecal coliform. Total GI cost increased as the target discharge, TSS, E coli, and Fecal coliform concentration at the outlet of the watershed was reduced. The tool placed a larger percentage of the GIs at the locations where most of the discharge and pollutant loads originated. This case study demonstrates that GIP-SWMM is a planning level decision support framework that allows for optimization of GIs and is adaptable for use in addressing regulatory compliance and practices across the U.S.