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Abstract
Fecal contamination is a significant source of water quality impairment globally. Aquatic ecosystems can provide an important ecosystem service of fecal contamination removal. Understanding the processes that regulate the removal of fecal contamination among river networks across flow conditions is critical. We applied a river network model, the Framework for Aquatic Modeling in the Earth System (FrAMES-Ecoli), to quantify removal of fecal indicator bacteria by river networks across flow conditions during summers in a series of New England watersheds of different characteristics. FrAMES-Ecoli simulates sources, transport, and riverine removal of Escherichia coli (E. coli). Aquatic E. coli removal was simulated in both the water column and the hyporheic zone, and is a function of hydraulic conditions, flow exchange rates with the hyporheic zone, and die-off in each compartment. We found that, at the river network scale during summers, removal by river networks can be high (19–99%) with variability controlled by hydrologic conditions, watershed size, and distribution of sources in the watershed. Hydrology controls much of the variability, with 68–99% of network scale inputs removed under base flow conditions and 19–85% removed during storm events. Removal by the water column alone could not explain the observed pattern in E. coli, suggesting that processes such as hyporheic removal must be considered. These results suggest that river network removal of fecal indicator bacteria should be taken into consideration in managing fecal contamination at critical downstream receiving waters.
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Zhang Q, Li Z, Zhu L, Zhang F, Sekerinski E, Han JC, Zhou Y. Real-time prediction of river chloride concentration using ensemble learning. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 291:118116. [PMID: 34537597 DOI: 10.1016/j.envpol.2021.118116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 08/27/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Real-time river chloride prediction has received a lot of attention for its importance in chloride control and management. In this study, an artificial neural network model (i.e., multi-layer perceptron, MLP) and a statistical inference model (i.e., stepwise-cluster analysis, SCA) are developed for predicting chloride concentration in stream water. Then, an ensemble learning model based on MLP and SCA is proposed to further improve the modeling accuracy. A case study of hourly river chloride prediction in the Grand River, Canada is presented to demonstrate the model applicability. The results show that the proposed ensemble learning model, MLP-SCA, provides the best overall performance compared with its two ensemble members in terms of RMSE, MAPE, NSE, and R2 with values of 11.58 mg/L, 27.55%, 0.90, and 0.90, respectively. Moreover, MLP-SCA is more competent for predicting extremely high chloride concentration. The prediction of observed concentrations above 150 mg/L has RMSE and MAPE values of 9.88 mg/L and 4.40%, respectively. The outstanding performance of the proposed MLP-SCA, particularly in extreme value prediction, indicates that it can provide reliable chloride prediction using commonly available data (i.e., conductivity, water temperature, river flow rate, and rainfall). The high-frequency prediction of chloride concentration in the Grand River can supplement the existing water quality monitoring programs, and further support the real-time control and management of chloride in the watershed. MLP-SCA is the first ensemble learning model for river chloride prediction and can be extended to other river systems for water quality prediction.
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Affiliation(s)
- Qianqian Zhang
- Chengdu University of Information Technology, Chengdu, 610225, China; Department of Civil Engineering, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Zhong Li
- Department of Civil Engineering, McMaster University, Hamilton, Ontario, L8S 4L8, Canada.
| | - Lu Zhu
- Department of Chemical Engineering, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Fei Zhang
- SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China
| | - Emil Sekerinski
- Department of Computing and Software, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Jing-Cheng Han
- Water Science and Environmental Engineering Research Center, College of Chemical and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Yang Zhou
- Water Science and Environmental Engineering Research Center, College of Chemical and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
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Moore J, Fanelli RM, Sekellick AJ. High-Frequency Data Reveal Deicing Salts Drive Elevated Specific Conductance and Chloride along with Pervasive and Frequent Exceedances of the U.S. Environmental Protection Agency Aquatic Life Criteria for Chloride in Urban Streams. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:778-789. [PMID: 31845802 DOI: 10.1021/acs.est.9b04316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Increasing specific conductance (SC) and chloride concentrations [Cl] negatively affect many stream ecosystems. We characterized spatial variability in SC, [Cl], and exceedances of Environmental Protection Agency [Cl] criteria using nearly 30 million high-frequency observations (2-15 min intervals) for SC and modeled [Cl] from 93 sites across three regions in the eastern United States: Southeast, Mid-Atlantic, and New England. SC and [Cl] increase substantially from south to north and within regions with impervious surface cover (ISC). In the Southeast, [Cl] weakly correlates with ISC, no [Cl] exceedances occur, and [Cl] concentrations are constant with time. In the Mid-Atlantic and New England, [Cl] and [Cl] exceedances strongly correlate with ISC. [Cl] criteria are frequently exceeded at sites with greater than 9-10% ISC and median [Cl] higher than 30-80 mg/L. Tens to hundreds of [Cl] exceedances observed annually at most of these sites help explain previous research where stream ecosystems showed changes at (primarily nonwinter) [Cl] as low as 30-40 mg/L. Mid-Atlantic chronic [Cl] exceedances occur primarily in December-March. In New England, exceedances are common in nonwinter months. [Cl] is increasing at nearly all Mid-Atlantic and New England sites with the largest increases at sites with higher [Cl].
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Affiliation(s)
| | - Rosemary M Fanelli
- U.S. Geological Survey , Maryland-Delaware-District of Columbia Water Science Center , 5522 Research Park Drive , Catonsville , Maryland 21228 , United States
| | - Andrew J Sekellick
- U.S. Geological Survey , Maryland-Delaware-District of Columbia Water Science Center , 5522 Research Park Drive , Catonsville , Maryland 21228 , United States
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Laceby JP, Kerr JG, Zhu D, Chung C, Situ Q, Abbasi S, Orwin JF. Chloride inputs to the North Saskatchewan River watershed: the role of road salts as a potential driver of salinization downstream of North America's northern most major city (Edmonton, Canada). THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 688:1056-1068. [PMID: 31726537 DOI: 10.1016/j.scitotenv.2019.06.208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 05/27/2023]
Abstract
Multiple anthropogenic activities are driving the salinization of freshwater environments threatening water resources worldwide. Accordingly, this research will first examine the spatial and temporal variability of major ions (i.e. Ca2+, Mg2+, Na+, K+, SO42-, CO32-, and HCO3-) upstream and downstream of the northernmost major city in North America (Edmonton, Canada). Second, this research will estimate the relative contributions of the major sources of chloride (Cl), the main constituent of road deicers, to the sub-basin around Edmonton. Monthly water quality data was for three sites on the North Saskatchewan River (NSR): Rocky Mountain House (RMH - downstream of the Rocky Mountain headwaters), Devon Bridge (upstream of Edmonton) and Pakan Bridge (downstream of Edmonton). Change ratios investigate the downstream alterations of major ions at Pakan and Devon, relative to RMH. Seasonal Kendall tests examine temporal trends (1987-2017). A mass-balance approach then quantifies the major sources of Cl in the sub-basin of the NSR between Devon and Pakan. Progressing from the Rocky Mountain headwaters (at RMH) to downstream of Edmonton (at Pakan), Cl- increased by >5.5 times, Na+ by 4.8 times and K by 2.7 times. No significant temporal trends for Cl-, Na+ and K+ were evident at Devon (upstream of Edmonton), whereas all three significantly increased at Pakan (downstream of Edmonton). Deicers (54%), agriculture (20%), along with waste water treatment plant and industrial effluent (15%) were the largest Cl sources in the NSR Devon-Pakan sub-basin. In total, 77 Gg yr-1 of Cl (or 6 t km2 yr-1) is added to the Devon-Pakan sub-basin, of which, 43 Gg yr-1 is retained. Understanding and managing the major drivers of freshwater salinization will be of increasing importance in the 21st century owing to the potential salinization of freshwater resources in the context of a changing climate.
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Affiliation(s)
- J P Laceby
- Environmental Monitoring and Science Division, Alberta Environment and Parks, 3535 Research Rd NW, Calgary, Alberta T2L 2K8, Canada.
| | - J G Kerr
- Environmental Monitoring and Science Division, Alberta Environment and Parks, 3535 Research Rd NW, Calgary, Alberta T2L 2K8, Canada
| | - D Zhu
- Water Resources Branch, Environment, Government of Yukon, 419 Range Road, Whitehorse, Yukon, Y1A, 3V1, Canada
| | - C Chung
- Environmental Monitoring and Science Division, Alberta Environment and Parks, 3535 Research Rd NW, Calgary, Alberta T2L 2K8, Canada
| | - Q Situ
- Environmental Monitoring and Science Division, Alberta Environment and Parks, 3535 Research Rd NW, Calgary, Alberta T2L 2K8, Canada
| | - S Abbasi
- Environmental Monitoring and Science Division, Alberta Environment and Parks, 3535 Research Rd NW, Calgary, Alberta T2L 2K8, Canada
| | - J F Orwin
- Environmental Monitoring and Science Division, Alberta Environment and Parks, 3535 Research Rd NW, Calgary, Alberta T2L 2K8, Canada
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Wilhelm JF, Bain DJ, Green MB, Bush KF, McDowell WH. Trace metals in Northern New England streams: Evaluating the role of road salt across broad spatial scales with synoptic snapshots. PLoS One 2019; 14:e0212011. [PMID: 30759149 PMCID: PMC6373959 DOI: 10.1371/journal.pone.0212011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 01/26/2019] [Indexed: 11/19/2022] Open
Abstract
Mobilization of trace metals from soils to surface waters can impact both human and ecosystem health. This study resamples a water sample archive to explore the spatial pattern of streamwater total concentrations of arsenic, cadmium, copper, lead, and zinc and their associations with biogeochemical controls in northern New England. Road deicing appears to result in elevated trace metal concentrations, as trace metal concentrations are strongly related to sodium concentrations and are most elevated when the sodium: chloride ratio is near 1.0 (~halite). Our results are consistent with previous laboratory and field studies that indicate cation exchange as a metal mobilization mechanism when road salt is applied to soils containing metals. This study also documents associations among sodium, chloride, dissolved organic carbon, iron, and metal concentrations, suggesting cation exchange mechanisms related to road deicing are not the only mechanisms that increase trace metal concentrations in surface waters. In addition to cation exchange, this study considers dissolved organic carbon complexation and oxidation-reduction conditions affecting metal mobility from soils in a salt-rich environment. These observations demonstrate that road deicing has the potential to increase streamwater trace metal concentrations across broad spatial scales and increase risks to human and ecosystem health.
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Affiliation(s)
- Jessica F. Wilhelm
- Center for the Environment, Plymouth State University, Plymouth, New Hampshire, United States of America
| | - Daniel J. Bain
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Mark B. Green
- Center for the Environment, Plymouth State University, Plymouth, New Hampshire, United States of America
- Northern Research Station, United States Forest Service, Durham, New Hampshire, United States of America
| | - Kathleen F. Bush
- Center for the Environment, Plymouth State University, Plymouth, New Hampshire, United States of America
- New Hampshire Department of Health and Human Services, Concord, New Hampshire, United States of America
| | - William H. McDowell
- Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, United States of America
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