The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Thomas A. Edge - One of the best experts on this subject based on the ideXlab platform.
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Foreshore beach sand as a reservoir and source of total phosphorus in Lake Ontario
2018Co-Authors: Zachery R. Staley, Phoenix Shum, Reid Vender, Thomas A. EdgeAbstract:Many regions around the Great Lakes have been designated Areas of Concern as a result of consistent water quality problems from pollutants like phosphorus and Escherichia coli, which cause eutrophication, beach postings and Beneficial Use Impairments. While foreshore beach sand is a potential reservoir for E. coli, there is less understanding of whether it might also be a reservoir and source of phosphorus for adjacent beach waters. We measured levels of E. coli, total phosphorus and soluble reactive phosphorus at Sunnyside and Rouge Beaches in the Toronto and Region Area of Concern, and stormwater Outfalls in the adjacent Humber and Rouge Rivers within their beachsheds. Additionally, we used microbial source tracking assays to detect human and gull fecal contamination. Soluble reactive phosphorus concentrations were highest in stormwater Outfalls, with concentrations as high as 556 µg l−1 at an outfall in the Sunnyside beachshed, and 4780 µg l−1 at an outfall in the Rouge beachshed. In contrast, the highest total phosphorus concentrations were typically found in foreshore beach sand pore water and were more associated with gull fecal contamination. Beach sand total phosphorus levels were as high as 10,600 µg l−1 at Sunnyside Beach, although the highest total phosphorus concentration measured (25,600 µg l−1) was in a Rouge River outfall. Concentrations of total phosphorus in Outfalls were significantly correlated with concentrations of E. coli in both beachsheds and the human microbial source tracking marker in the Sunnyside beachshed Outfalls. These results indicate that stormwater Outfalls with sewage cross-contamination can deliver high concentrations of total phosphorus, soluble reactive phosphorus and fecal bacterial contamination to associated beachsheds. Further, similar to E. coli, foreshore beach sand can act as a reservoir of total phosphorus and a source for adjacent water bodies via wave action or groundwater discharge. High phosphorus inputs from beach sand could contribute localized changes to microbial communities and unique eutrophication effects along beach shorelines.
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comparison of microbial and chemical source tracking markers to identify fecal contamination sources in the humber river toronto ontario canada and associated storm water Outfalls
Applied and Environmental Microbiology, 2016Co-Authors: Zachery R. Staley, Josey Grabuski, Ed Sverko, Thomas A. EdgeAbstract:ABSTRACT Storm water runoff is a major source of pollution, and understanding the components of storm water discharge is essential to remediation efforts and proper assessment of risks to human and ecosystem health. In this study, culturable Escherichia coli and ampicillin-resistant E. coli levels were quantified and microbial source tracking (MST) markers (including markers for general Bacteroidales spp., human, ruminant/cow, gull, and dog) were detected in storm water Outfalls and sites along the Humber River in Toronto, Ontario, Canada, and enumerated via endpoint PCR and quantitative PCR (qPCR). Additionally, chemical source tracking (CST) markers specific for human wastewater (caffeine, carbamazepine, codeine, cotinine, acetaminophen, and acesulfame) were quantified. Human and gull fecal sources were detected at all sites, although concentrations of the human fecal marker were higher, particularly in Outfalls (mean outfall concentrations of 4.22 log10 copies, expressed as copy numbers [CN]/100 milliliters for human and 0.46 log10 CN/100 milliliters for gull). Higher concentrations of caffeine, acetaminophen, acesulfame, E. coli, and the human fecal marker were indicative of greater raw sewage contamination at several sites (maximum concentrations of 34,800 ng/liter, 5,120 ng/liter, 9,720 ng/liter, 5.26 log10 CFU/100 ml, and 7.65 log10 CN/100 ml, respectively). These results indicate pervasive sewage contamination at storm water Outfalls and throughout the Humber River, with multiple lines of evidence identifying Black Creek and two storm water Outfalls with prominent sewage cross-connection problems requiring remediation. Limited data are available on specific sources of pollution in storm water, though our results indicate the value of using both MST and CST methodologies to more reliably assess sewage contamination in impacted watersheds. IMPORTANCE Storm water runoff is one of the most prominent non-point sources of biological and chemical contaminants which can potentially degrade water quality and pose risks to human and ecosystem health. Therefore, identifying fecal contamination in storm water runoff and Outfalls is essential for remediation efforts to reduce risks to public health. This study employed multiple methods of identifying levels and sources of fecal contamination in both river and storm water outfall sites, evaluating the efficacy of using culture-based enumeration of E. coli, molecular methods of determining the source(s) of contamination, and CST markers as indicators of fecal contamination. The results identified pervasive human sewage contamination in storm water Outfalls and throughout an urban watershed and highlight the utility of using both MST and CST to identify raw sewage contamination.
Richard A Fenner - One of the best experts on this subject based on the ideXlab platform.
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the impact of natural flood management on the performance of surface drainage systems a case study in the calder valley
Journal of Hydrology, 2020Co-Authors: Charlie Ferguson, Richard A FennerAbstract:Abstract The evaluation of Natural Flood Management (NFM) has traditionally focused on the ability of interventions to mitigate downstream fluvial flooding by attenuating catchment response. However, the justification for the implementation of NFM projects at a local level is often supported by other benefits provided by such interventions (e.g. improvements to water quality or biodiversity). This study investigates the potential for a further, largely unrecognised, benefit. It is suggested that, by moderating water levels in downstream watercourses, upstream interventions could also help sustain free discharge from drainage Outfalls, thereby improving the performance of urban surface drainage systems. A coupled modelling methodology is applied to the upper Calder Valley and the surface drainage in an area of the downstream town of Todmorden. The rural response and subsequent NFM interventions are characterised using hydrological (Dynamic TOPMODEL) and hydraulic (HEC-RAS) models. Several downstream surface drainage systems are then incorporated using an Infoworks ICM model to examine their response to changes in outfall inundation. The results suggest that catchment-scale tree planting and in-channel woody debris create modest benefits for downstream surface drainage systems. Under frequent storm events (e.g. a 1 in 10 year storm), the inundation of low-lying Outfalls is completely removed. As storm severity increases (and surface flooding becomes an issue), impact from upstream NFM attenuation on outfall inundation durations diminishes significantly. However, the slight delay in rural response allows more water to escape surface systems, increasing the effective capacity of networks and reducing surface flooding. For instance, outfall inundation during an estimated 20 year event is delayed by 0.5 hours, which results in up to 25% reduction in surface flood volumes. While the benefits are limited in extent, this modelling indicates that NFM can help improve downstream surface drainage performance.
Nalini Sankararamakrishnan - One of the best experts on this subject based on the ideXlab platform.
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Chemical tracers as indicator of human fecal coliforms at storm water Outfalls.
Environment International, 2005Co-Authors: Nalini SankararamakrishnanAbstract:Indicators to distinguish between fecal coliforms of human and animal origin were investigated in water from storm sewer Outfalls to a coastal lake during wet and dry weather. The ratio of fecal coliform relative to fecal streptococci count was used as the microbiological indicator. Concentrations of human-activities originated caffeine, anionic surfactant, fluoride, and fluorescence whitening agent (FWA) were used as chemical indicators. The ratio of fecal coliform to fecal streptococci ranged from 0.2 to 3.0, during wet weather making it difficult to interpret the origin of fecal pollution. However, concentrations of caffeine, anionic surfactant, fluoride, and FWA in storm water outflow during wet weather were much higher than those in the lake water during dry weather, indicating the presence of human waste at storm water outfall. Strong correlation between fecal coliform counts and chemical parameter values further indicated the human contribution to the fecal coliform count. In addition, a strong correlation among the chemical parameters suggested that only one of them is needed as chemical tracer to detect the presence of human input.
Christopher J Lowe - One of the best experts on this subject based on the ideXlab platform.
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risks of hypoxia and acidification in the high energy coastal environment near victoria canada s untreated municipal sewage Outfalls
Marine Pollution Bulletin, 2018Co-Authors: Debby Ianson, Jeremy Krogh, Roberta C Hamme, Christopher J LoweAbstract:Abstract Wastewater disposal often has deleterious impacts on the receiving environment. Low dissolved oxygen levels are particularly concerning. Here, we investigate the impacts on dissolved oxygen and carbon chemistry of screened municipal wastewater in the marine waters off Victoria, Canada. We analyzed data from undersea moorings, ship-based monitoring, and remotely-operated vehicle video. We used these observations to construct a two-layer model of the nearfield receiving environment. Despite the lack of advanced treatment, dissolved oxygen levels near the Outfalls were well above a 62 μmol kg−1 hypoxic threshold. Furthermore, the impact on water column oxygen at the outfall is likely
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effect of receiving environment on the transport and fate of polybrominated diphenyl ethers near two submarine municipal Outfalls
Environmental Toxicology and Chemistry, 2012Co-Authors: Pamela M Dinn, Sophia C Johannessen, Robie W Macdonald, Christopher J Lowe, Michael J WhiticarAbstract:The fate of contaminants entering the marine environment through wastewater Outfalls depends on the contaminant's persistence and affinity for particles. However, the physical characteristics of the receiving environment, for example, current velocity and sedimentary processes, may be even more important. Because of the complexity of natural settings and the lack of appropriate comparative settings, this is not frequently evaluated quantitatively. The authors investigated the near-field accumulation of particle-reactive polybrominated diphenyl ethers (PBDEs) entering coastal waters by way of two municipal Outfalls: one discharging into a high-energy, low-sedimentation environment near Victoria, BC, Canada; the other into a low-energy, high-sedimentation environment, near Vancouver, BC. The authors used 210Pb profiles in box cores together with an advection-diffusion model to determine surface mixing and sedimentation rates, and to model the depositional history of PBDEs at these sites. Surprisingly, 88 to 99% of PBDEs were dispersed beyond the near-field at both sites, but a greater proportion of PBDEs was captured in the sediment near the Vancouver outfall where rapid burial was facilitated by inorganic sediment supplied from the nearby Fraser River. Although the discharge of PBDEs was much lower from the Victoria outfall than from Vancouver, some sediment PBDE concentrations were higher near Victoria. Environ. Toxicol. Chem. 2012;31:566–573. © 2011 SETAC
Leigh A Gray - One of the best experts on this subject based on the ideXlab platform.
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metal contamination of sediments associated with deepwater ocean sewage Outfalls sydney australia
Marine Pollution Bulletin, 1996Co-Authors: Leigh A GrayAbstract:Abstract The New South Wales Environment Protection Authority has recently completed a programme to evaluate the impact on near-shore shelf sediments, following the commissioning of three new deepwater sewage Outfalls off Sydney, Australia. These Outfalls discharge a total of around 1300 ML day−1 of primary treated sewage derived from domestic and industrial sources. The study compared three locations that were close to the Outfalls (likely impacted) and three locations far from the Outfalls (likely non-impacted). Four zones were sampled within each location to provide estimates of spatial variability. Three samples of surface sediment were collected from each zone at six monthly intervals over a three year period which encompassed the commissioning of the Outfalls. The results of the study suggest that, associated with the commissioning of the three deepwater Outfalls, there has not been a significant effect on the concentration of trace metals in the sediments surrounding the Outfalls. The concentrations of trace metals in the whole sediment generally were close to the world-wide background levels quoted in the literature, and generally reflected the distribution pattern of the sedimentary fines (
