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Smith GJ, McDowell RW, Condron LM, Daly K, Ó hUallacháin D, Fenton O. Phosphorus and iron-oxide transport from a hydrologically isolated grassland hillslope. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 329:117008. [PMID: 36584514 DOI: 10.1016/j.jenvman.2022.117008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Dissolved reactive phosphorus (DRP) loss from agricultural soils can negatively affect water quality. Shallow subsurface pathways can dominate P losses in grassland soils, especially in wetter months when waterlogging is common. This study investigated the processes controlling intra- and inter-event and seasonal DRP losses from poorly drained permanent grassland hillslope plots. Temporal flow related water samples were taken from surface runoff and subsurface (in-field pipe) discharge, analysed, and related to the likelihood of anaerobic conditions and redoximorphic species including nitrate (NO3-) over time. Subsurface drainage accounted for 89% of total losses. Simple linear regression and correlation matrices showed positive relationships between DRP and iron and soil moisture deficit; and negative relationships between these three factors and NO3- concentrations in drainage. These data indicate that waterlogging and low NO3- concentrations control the release of P in drainage, potentially via reductive dissolution. The relationship between DRP and metal release was less obvious in surface runoff, as nutrients gathered from P-rich topsoil camoflaged redox reactions. The data suggest a threshold in NO3- concentrations that could exacerbate P losses, even in low P soils. Knowledge of how nutrients interact with soil drainage throughout the year can be used to better time soil N and P inputs via, for example, fertiliser or grazing to avoid to excessive P loss that could harm water quality.
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Affiliation(s)
- G J Smith
- Faculty of Agriculture and Life Sciences, P O Box 85084, Lincoln University, Lincoln 7647, Christchurch, New Zealand
| | - R W McDowell
- Faculty of Agriculture and Life Sciences, P O Box 85084, Lincoln University, Lincoln 7647, Christchurch, New Zealand; AgResearch, Lincoln Science Centre, Private Bag 4749, Christchurch, 8140, New Zealand.
| | - L M Condron
- Faculty of Agriculture and Life Sciences, P O Box 85084, Lincoln University, Lincoln 7647, Christchurch, New Zealand
| | - K Daly
- Teagasc Crops, Environment and Land Use Programme, Johnstown Castle, Wexford, Ireland
| | - D Ó hUallacháin
- Teagasc Crops, Environment and Land Use Programme, Johnstown Castle, Wexford, Ireland
| | - O Fenton
- Teagasc Crops, Environment and Land Use Programme, Johnstown Castle, Wexford, Ireland
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Kim H, Jakobsen R, Aamand J, Claes N, Erlandsen M, Hansen B. Upscaling of Denitrification Rates from Point to Catchment Scales for Modeling of Nitrate Transport and Retention. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15821-15830. [PMID: 34807591 DOI: 10.1021/acs.est.1c04593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The spatial and temporal variability of denitrification makes it challenging to integrate conceptual, process-based understandings of nitrate transport and retention into numerical modeling at the catchment scale, although it is critical for the realism and predictive power of the model. In this study, we propose a novel approach where the conceptual understandings of the spatial structure of denitrification zones and the corresponding representative denitrification rates are transformed into a form that can be integrated into a multi-point statistical simulation framework. This is done by constructing a denitrification training image (TI) coupled to a geophysically based TI of the hydrogeological structure. The field observations and laboratory analyses of denitrification rates and the chemistry of water and sediment revealed that the study catchment's subsurface can be characterized by three zones: (1) the oxic zone with no nitrate reduction; (2) the slow-denitrification zone (mean of ln-transformed rate = -1.19 ± 0.52 mg N L-1 yr-1); and (3) the high-denitrification zone (mean of ln-transformed rate = 3.86 ± 1.96 mg N L-1 yr-1). The underlying controls on the spatial distribution of these zones and the representativeness of denitrification rates were investigated. Then, a TI illustrating the subsurface structure of the denitrification zone was constructed by synthesizing the results of these geochemical interpretations and the hydrogeology TI.
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Affiliation(s)
- Hyojin Kim
- Department of Groundwater and Quaternary Geology Mapping, Geological Survey of Denmark and Greenland (GEUS), C.F. Møllers Allé 8, Building 1110, 8000 Aarhus, Denmark
| | - Rasmus Jakobsen
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Jens Aamand
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Niels Claes
- HydroGeophysics Group, Department of Geoscience, Aarhus University, C.F. Møllers Allé 4, 8000 Aarhus, Denmark
| | - Mogens Erlandsen
- Section for Biostatistics, Department of Public Health, Aarhus University (Retired), Bartholins Allé 2, Building 1260, 8000 Aarhus, Denmark
| | - Birgitte Hansen
- Department of Groundwater and Quaternary Geology Mapping, Geological Survey of Denmark and Greenland (GEUS), C.F. Møllers Allé 8, Building 1110, 8000 Aarhus, Denmark
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Iteba JO, Hein T, Singer GA, Masese FO. Livestock as vectors of organic matter and nutrient loading in aquatic ecosystems in African savannas. PLoS One 2021; 16:e0257076. [PMID: 34495982 PMCID: PMC8425544 DOI: 10.1371/journal.pone.0257076] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 08/23/2021] [Indexed: 11/19/2022] Open
Abstract
Populations of large wildlife have declined in many landscapes around the world, and have been replaced or displaced by livestock. The consequences of these changes on the transfer of organic matter (OM) and nutrients from terrestrial to aquatic ecosystems are not well understood. We used behavioural data, excretion and egestion rates and C: N: P stoichiometry of dung and urine of zebu cattle, to develop a metabolism-based estimate of loading rates of OM (dung), C, N and P into the Mara River, Kenya. We also directly measured the deposition of OM and urine by cattle into the river during watering. Per head, zebu cattle excrete and/or egest 25.6 g dry matter (DM, 99.6 g wet mass; metabolism) - 27.7 g DM (direct input) of OM, 16.0-21.8 g C, 5.9-9.6 g N, and 0.3-0.5 g P per day into the river. To replace loading rates OM of an individual hippopotamus by cattle, around 100 individuals will be needed, but much less for different elements. In parts of the investigated sub-catchments loading rates by cattle were equivalent to or higher than that of the hippopotamus. The patterns of increased suspended materials and nutrients as a result of livestock activity fit into historical findings on nutrients concentrations, dissolved organic carbon and other variables in agricultural and livestock areas in the Mara River basin. Changing these patterns of carbon and nutrient transport and cycling are having significant effects on the structure and functioning of both terrestrial and aquatic ecosystems.
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Affiliation(s)
- Jacob O. Iteba
- Department of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
- Department of Fisheries and Aquatic Sciences, University of Eldoret, Eldoret, Kenya
| | - Thomas Hein
- Department of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
- WasserCluster Lunz, Lunz am See, Austria
| | - Gabriel A. Singer
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Frank O. Masese
- Department of Fisheries and Aquatic Sciences, University of Eldoret, Eldoret, Kenya
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Aquatic Science and Ecosystems Group, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
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McDowell RW, Noble A, Pletnyakov P, Haggard BE, Mosley LM. Global mapping of freshwater nutrient enrichment and periphyton growth potential. Sci Rep 2020; 10:3568. [PMID: 32107412 PMCID: PMC7046692 DOI: 10.1038/s41598-020-60279-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/10/2020] [Indexed: 11/09/2022] Open
Abstract
Periphyton (viz. algal) growth in many freshwater systems is associated with severe eutrophication that can impair productive and recreational use of water by billions of people. However, there has been limited analysis of periphyton growth at a global level. To predict where nutrient over-enrichment and undesirable periphyton growth occurs, we combined several databases to model and map global dissolved and total nitrogen (N) and phosphorus (P) concentrations, climatic and catchment characteristics for up to 1406 larger rivers that were analysed between 1990 and 2016. We predict that 31% of the global landmass contained catchments may exhibit undesirable levels of periphyton growth. Almost three-quarters (76%) of undesirable periphyton growth was caused by P-enrichment and mapped to catchments dominated by agricultural land in North and South America and Europe containing 1.7B people. In contrast, undesirable periphyton growth due to N-enrichment was mapped to parts of North Africa and parts of the Middle East and India affecting 280 M people. The findings of this global modelling approach can be used by landowners and policy makers to better target investment and actions at finer spatial scales to remediate poor water quality owing to periphyton growth.
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Affiliation(s)
- R W McDowell
- AgResearch, Lincoln Science Centre, Private Bag 4749, Christchurch, 8140, New Zealand. .,Faculty of Agriculture and Life Sciences, P O Box 84, Lincoln University, Lincoln, 7647, Christchurch, New Zealand.
| | - A Noble
- AgResearch, Lincoln Science Centre, Private Bag 4749, Christchurch, 8140, New Zealand
| | - P Pletnyakov
- AgResearch, Lincoln Science Centre, Private Bag 4749, Christchurch, 8140, New Zealand
| | - B E Haggard
- Biological and Agricultural Engineering Department, University of Arkansas, Fayetteville, AR, 72703, USA
| | - L M Mosley
- School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
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Zhang Q. Synthesis of nutrient and sediment export patterns in the Chesapeake Bay watershed: Complex and non-stationary concentration-discharge relationships. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 618:1268-1283. [PMID: 29103643 DOI: 10.1016/j.scitotenv.2017.09.221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/15/2017] [Accepted: 09/21/2017] [Indexed: 06/07/2023]
Abstract
Derived from river monitoring data, concentration-discharge (C-Q) relationships are useful indicators of riverine export dynamics. A top-down synthesis of C-Q patterns was conducted for suspended sediment (SS), total phosphorus (TP), and total nitrogen (TN) for nine major tributaries (15 monitoring sites) to Chesapeake Bay, which represent diverse characteristics in terms of land use, physiography, and hydrological settings. Model coefficients from the recently-developed Weighted Regressions on Time, Discharge, and Season (WRTDS) method were used to make informative interpretation of C-Q relationships. Unlike many previous C-Q studies that focused on stormflow conditions, this approach allows simultaneous examination of various discharge conditions within an uncertainty framework. This synthesis on WRTDS coefficients (i.e., the sensitivity of concentration to discharge) has offered new insights on the complexity of watershed function. Results show that watershed export has been dominated by mobilization patterns for SS and TP (particulate-dominated species) and chemostasis patterns for TN (dissolved-dominated species) under many river discharge conditions. Among nine possible modalities of low-flow vs. high-flow patterns, the three most frequent modalities are mobilization vs. mobilization (17 cases), chemostasis vs. mobilization (13 cases), and chemostasis vs. chemostasis (7 cases), representing 82% of all 45 watershed-constituent pairs. The general lack of dilution patterns may suggest that none of these constituents has been supply-limited in these watersheds. For many watershed-constituent combinations, results show clear temporal non-stationarity in C-Q relationships under selected time-invariant discharges, reflecting major changes in dominant watershed sources due to anthropogenic actions. These results highlight the potential pitfalls of assuming fixed C-Q relationships in the record. Overall, this work demonstrates the utility of WRTDS model coefficients for interpretation of river water-quality data and for generation of sensible hypotheses on dominant processes in different watersheds. The approach is readily adaptable to other river systems, where long-term discretely-sampled data are available, to decipher complex interactions between hydrological and biogeochemical processes.
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Affiliation(s)
- Qian Zhang
- University of Maryland Center for Environmental Science/U.S. Environmental Protection Agency Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA; Formerly, Johns Hopkins University, Department of Geography and Environmental Engineering, 3400 North Charles Street, Ames Hall 313, Baltimore, MD 21218, USA.
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7
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Lefrancq M, Jadas-Hécart A, La Jeunesse I, Landry D, Payraudeau S. High frequency monitoring of pesticides in runoff water to improve understanding of their transport and environmental impacts. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 587-588:75-86. [PMID: 28242219 DOI: 10.1016/j.scitotenv.2017.02.022] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 05/26/2023]
Abstract
Rainfall-induced peaks in pesticide concentrations can occur rapidly. Low frequency sampling may therefore largely underestimate maximum pesticide concentrations and fluxes. Detailed storm-based sampling of pesticide concentrations in runoff water to better predict pesticide sources, transport pathways and toxicity within the headwater catchments is lacking. High frequency monitoring (2min) of seven pesticides (Dimetomorph, Fluopicolide, Glyphosate, Iprovalicarb, Tebuconazole, Tetraconazole and Triadimenol) and one degradation product (AMPA) were assessed for 20 runoff events from 2009 to 2012 at the outlet of a vineyard catchment in the Layon catchment in France. The maximum pesticide concentrations were 387μgL-1. Samples from all of the runoff events exceeded the legal limit of 0.1μgL-1 for at least one pesticide (European directive 2013/39/EC). High resolution sampling used to detect the peak pesticide levels revealed that Toxic Units (TU) for algae, invertebrates and fish often exceeded the European Uniform principles (25%). The point and average (time or discharge-weighted) concentrations indicated up to a 30- or 4-fold underestimation of the TU obtained when measuring the maximum concentrations, respectively. This highlights the important role of sampling methods for assessing peak exposure. High resolution sampling combined with concentration-discharge hysteresis analyses revealed that clockwise responses were predominant (52%), indicating that Hortonian runoff is the prevailing surface runoff trigger mechanism in the study catchment. The hysteresis patterns for suspended solids and pesticides were highly dynamic and storm- and chemical-dependent. Intense rainfall events induced stronger C-Q hysteresis (magnitude). This study provides new insights into the complexity of pesticide dynamics in runoff water and highlights the ability of hysteresis analysis to improve understanding of pesticide supply and transport.
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Affiliation(s)
- Marie Lefrancq
- University of Angers, LETG-Angers UMR CNRS 6554, 2 bd Lavoisier, 49045 Angers, France.
| | - Alain Jadas-Hécart
- University of Angers, LETG-Angers UMR CNRS 6554, 2 bd Lavoisier, 49045 Angers, France
| | - Isabelle La Jeunesse
- University of Angers, LETG-Angers UMR CNRS 6554, 2 bd Lavoisier, 49045 Angers, France; University François Rabelais of Tours, Citeres UMR CNRS 7324, 33, allée Ferdinand de Lesseps, B.P. 60449, 37204 Tours cedex 3, France
| | - David Landry
- University of Angers, LETG-Angers UMR CNRS 6554, 2 bd Lavoisier, 49045 Angers, France
| | - Sylvain Payraudeau
- University of Strasbourg, CNRS, ENGEES, LHyGeS UMR 7517, 1 rue Blessig, F-67084 Strasbourg, France
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8
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Cassidy R, Doody DG, Watson CJ. Impact of legacy soil phosphorus on losses in drainage and overland flow from grazed grassland soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 575:474-484. [PMID: 28029454 DOI: 10.1016/j.scitotenv.2016.07.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/07/2016] [Accepted: 07/09/2016] [Indexed: 05/26/2023]
Abstract
Rates and quantities of legacy soil phosphorus (P) lost from agricultural soils, and the timescales for positive change to water quality, remain unclear. From 2000 to 2004 five 0.2ha grazed grassland plots located on a drumlin hillslope in Northern Ireland, received chemical fertiliser applications of 0, 10, 20, 40, 80kgPha-1yr-1 resulting in soil Olsen P concentrations of 19, 24, 28, 38 and 67mgPL-1, respectively, after which applications ceased. Soil Olsen P and losses to overland flow and drainage were monitored from 2005 to 2011 on an event and weekly flow proportional basis, respectively. Soluble reactive P and total P time series were synchronised with daily rainfall and modelled soil moisture deficits. From 2005 to 2011 soil Olsen P decline was proportional to soil P status with a 43% reduction in the plot at 67mgPL-1 in 2004 and a corresponding 12% reduction in the plot with lowest soil P. However, there was no significant difference in the flow-weighted mean concentration for overland flow among plots, all of which exceeded 0.035mgL-1 in >98% of events. Strong interannual and event variations in losses were observed with up to 65% of P being lost during a single rainfall event. P concentrations in drainage flow were independent of Olsen P and drain efficiency was potentially the primary control on concentrations, with the highest concentrations recorded in the plot at 38mgL-1 Olsen P in 2004 (up to 2.72mgL-1). Hydrological drivers, particularly antecedent soil moisture, had a strong influence on P loss in both overland and drainage flow, with higher concentrations recorded above a soil moisture deficit threshold of 7mm. This study demonstrates that on some soil types, legacy P poses a significant long term threat to water quality, even at agronomically optimum soil P levels.
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Affiliation(s)
- Rachel Cassidy
- Agri-Environment Branch, Agri-Food and Biosciences Institute (AFBI), Newforge Lane, Belfast, BT9 5PX, Northern Ireland.
| | - Donnacha G Doody
- Agri-Environment Branch, Agri-Food and Biosciences Institute (AFBI), Newforge Lane, Belfast, BT9 5PX, Northern Ireland
| | - Catherine J Watson
- Agri-Environment Branch, Agri-Food and Biosciences Institute (AFBI), Newforge Lane, Belfast, BT9 5PX, Northern Ireland
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Thomas IA, Jordan P, Mellander PE, Fenton O, Shine O, Ó hUallacháin D, Creamer R, McDonald NT, Dunlop P, Murphy PNC. Improving the identification of hydrologically sensitive areas using LiDAR DEMs for the delineation and mitigation of critical source areas of diffuse pollution. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 556:276-290. [PMID: 26974575 DOI: 10.1016/j.scitotenv.2016.02.183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 06/05/2023]
Abstract
Identifying critical source areas (CSAs) of diffuse pollution in agricultural catchments requires the accurate identification of hydrologically sensitive areas (HSAs) at highest propensity for generating surface runoff and transporting pollutants. A new GIS-based HSA Index is presented that improves the identification of HSAs at the sub-field scale by accounting for microtopographic controls. The Index is based on high resolution LiDAR data and a soil topographic index (STI) and also considers the hydrological disconnection of overland flow via topographic impediment from flow sinks. The HSA Index was applied to four intensive agricultural catchments (~7.5-12km(2)) with contrasting topography and soil types, and validated using rainfall-quickflow measurements during saturated winter storm events in 2009-2014. Total flow sink volume capacities ranged from 8298 to 59,584m(3) and caused 8.5-24.2% of overland-flow-generating-areas and 16.8-33.4% of catchment areas to become hydrologically disconnected from the open drainage channel network. HSA maps identified 'breakthrough points' and 'delivery points' along surface runoff pathways as vulnerable points where diffuse pollutants could be transported between fields or delivered to the open drainage network, respectively. Using these as proposed locations for targeting mitigation measures such as riparian buffer strips reduced potential costs compared to blanket implementation within an example agri-environment scheme by 66% and 91% over 1 and 5years respectively, which included LiDAR DEM acquisition costs. The HSA Index can be used as a hydrologically realistic transport component within a fully evolved sub-field scale CSA model, and can also be used to guide the implementation of 'treatment-train' mitigation strategies concurrent with sustainable agricultural intensification.
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Affiliation(s)
- I A Thomas
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Co., Wexford, Ireland; School of Geography and Environmental Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom.
| | - P Jordan
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Co., Wexford, Ireland; School of Geography and Environmental Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom.
| | - P-E Mellander
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Co., Wexford, Ireland.
| | - O Fenton
- Teagasc, Environmental Research Centre, Johnstown Castle, Wexford, Co., Wexford, Ireland.
| | - O Shine
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Co., Wexford, Ireland.
| | - D Ó hUallacháin
- Teagasc, Environmental Research Centre, Johnstown Castle, Wexford, Co., Wexford, Ireland.
| | - R Creamer
- Teagasc, Environmental Research Centre, Johnstown Castle, Wexford, Co., Wexford, Ireland.
| | - N T McDonald
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Co., Wexford, Ireland.
| | - P Dunlop
- School of Geography and Environmental Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom.
| | - P N C Murphy
- Environment and Sustainable Resource Management Section, School of Agriculture and Food Science, University College Dublin, Dublin 4, Ireland.
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Gassmann M, Olsson O, Stamm C, Weiler M, Kümmerer K. Physico-chemical characteristics affect the spatial distribution of pesticide and transformation product loss to an agricultural brook. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 532:733-743. [PMID: 26119387 DOI: 10.1016/j.scitotenv.2015.06.068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 06/17/2015] [Accepted: 06/17/2015] [Indexed: 06/04/2023]
Abstract
Diffuse entry of pesticide residues from agriculture into rivers is spatially unevenly distributed. Therefore, the identification of critical source areas (CSAs) may support water quality management in agricultural catchments. In contrast to former studies, we followed the hypothesis that not only hydrological and topographical characteristics but also physico-chemical properties of pesticide residues have a major influence on their loss to rivers and on corresponding formation of CSAs. We designed a virtual experiment, i.e. a numerical experiment as close as possible to environmental conditions, in a headwater catchment where pronounced spatial differences in hydrological transport processes were identified in the past. 144 scenarios with different combinations of adsorption coefficients (KOC = 10-1000 ml/g) and transformation half-lives (DT50 = 3-60 days) for pesticide parent compounds (PCs) and their transformation products (TPs) were simulated using the catchment-scale spatially distributed reactive transport model ZIN-AgriTra. Export fractions of substances in the virtual experiment ranged from 0.001-15% for pesticides and 0.001-1.8% for TPs. The results of the scenario investigations suggest that more of the calculated export mass variability could be attributed to KOC than to DT50 for both PCs and TPs. CSAs for TPs were spatially more equally distributed in the catchment than for PC export which was likely an effect of changing physico-chemical properties during transformation. The ranking of highest export fields was different between PCs and TPs for most of the investigated scenarios but six fields appeared among the top ten export fields in 95% of the scenarios, which shows the influence of site characteristics such as tile drains or soil properties in the catchment. Thus, the highest export fields were determined by a combination of site characteristics and substance characteristics. Therefore, despite the challenge of widely differing physico-chemical characteristics of pesticides on the market, these characteristics are an important consideration when delineating pesticide residue CSAs.
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Affiliation(s)
- M Gassmann
- Chair of Sustainable Chemistry and Material Resources, Leuphana University of Lüneburg, Lüneburg, Germany; Chair for Water Quality Management - Modelling and Simulation, University of Kassel, Kassel, Germany.
| | - O Olsson
- Chair of Sustainable Chemistry and Material Resources, Leuphana University of Lüneburg, Lüneburg, Germany
| | - C Stamm
- Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
| | - M Weiler
- Chair of Hydrology, University of Freiburg, Germany
| | - K Kümmerer
- Chair of Sustainable Chemistry and Material Resources, Leuphana University of Lüneburg, Lüneburg, Germany
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von Freyberg J, Radny D, Gall HE, Schirmer M. Implications of hydrologic connectivity between hillslopes and riparian zones on streamflow composition. JOURNAL OF CONTAMINANT HYDROLOGY 2014; 169:62-74. [PMID: 25106837 DOI: 10.1016/j.jconhyd.2014.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 07/02/2014] [Accepted: 07/08/2014] [Indexed: 06/03/2023]
Abstract
Hydrological responses in mountainous headwater catchments are often highly non-linear with a distinct threshold-related behavior, which is associated to steep hillslopes, shallow soils and strong climatic variability. A holistic understanding of the dominant physical processes that control streamflow generation and non-linearity is required in order to assess potential negative effects of agricultural land use and water management in those areas. Therefore, streamflow generation in a small pre-Alpine headwater catchment (Upper Rietholzbach (URHB), ~1km(2)) was analyzed over a 2-year period by means of rainfall-response analysis and water quality data under explicit consideration of the joint behaviors of climate forcing and shallow groundwater dynamics. The runoff coefficients indicate that only a small fraction of the total catchment area (1-26%) generates streamflow during rainfall events. Hereby, the valley bottom areas (riparian zones) were the most important event-water source whereas only the lower parts of the hillslopes became hydrologically connected to the river network with higher antecedent moisture conditions. However, a distinct threshold-like behavior could not be observed, suggesting a more continuous shift from a riparian-zone to a more hillslope-dominated streamflow hydrograph. Regular manure application on the hillslopes in combinations with lateral hillslope groundwater flux and long groundwater residence times in the riparian zones resulted in a higher mineralization (e.g., total phosphorous) and significant denitrification in the valley bottom area. Despite the important role of the riparian zones for event-flow generation in the URHB, their nutrient buffer capacity is expected to be small due to the low permeability of the local subsurface material. The findings of this integrated analysis are summarized in a conceptual framework describing the hydrological functioning of hillslopes and riparian zones in the URHB.
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Affiliation(s)
- Jana von Freyberg
- Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, 8600 Dübendorf, Switzerland; University of Neuchâtel, Centre for Hydrogeology and Geothermics, 2000 Neuchâtel, Switzerland.
| | - Dirk Radny
- Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, 8600 Dübendorf, Switzerland
| | - Heather E Gall
- The Pennsylvania State University, Department of Agricultural and Biological Engineering, 232 Agricultural Engineering Building, University Park, PA, 16802
| | - Mario Schirmer
- Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, 8600 Dübendorf, Switzerland; University of Neuchâtel, Centre for Hydrogeology and Geothermics, 2000 Neuchâtel, Switzerland
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12
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Shore M, Jordan P, Mellander PE, Kelly-Quinn M, Wall DP, Murphy PNC, Melland AR. Evaluating the critical source area concept of phosphorus loss from soils to water-bodies in agricultural catchments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 490:405-415. [PMID: 24863139 DOI: 10.1016/j.scitotenv.2014.04.122] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 04/28/2014] [Accepted: 04/29/2014] [Indexed: 06/03/2023]
Abstract
Using data collected from six basins located across two hydrologically contrasting agricultural catchments, this study investigated whether transport metrics alone provide better estimates of storm phosphorus (P) loss from basins than critical source area (CSA) metrics which combine source factors as well. Concentrations and loads of P in quickflow (QF) were measured at basin outlets during four storm events and were compared with dynamic (QF magnitude) and static (extent of highly-connected, poorly-drained soils) transport metrics and a CSA metric (extent of highly-connected, poorly-drained soils with excess plant-available P). Pairwise comparisons between basins with similar CSA risks but contrasting QF magnitudes showed that QF flow-weighted mean TRP (total molybdate-reactive P) concentrations and loads were frequently (at least 11 of 14 comparisons) more than 40% higher in basins with the highest QF magnitudes. Furthermore, static transport metrics reliably discerned relative QF magnitudes between these basins. However, particulate P (PP) concentrations were often (6 of 14 comparisons) higher in basins with the lowest QF magnitudes, most likely due to soil-management activities (e.g. ploughing), in these predominantly arable basins at these times. Pairwise comparisons between basins with contrasting CSA risks and similar QF magnitudes showed that TRP and PP concentrations and loads did not reflect trends in CSA risk or QF magnitude. Static transport metrics did not discern relative QF magnitudes between these basins. In basins with contrasting transport risks, storm TRP concentrations and loads were well differentiated by dynamic or static transport metrics alone, regardless of differences in soil P. In basins with similar transport risks, dynamic transport metrics and P source information additional to soil P may be required to predict relative storm TRP concentrations and loads. Regardless of differences in transport risk, information on land use and management, may be required to predict relative differences in storm PP concentrations between these agricultural basins.
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Affiliation(s)
- M Shore
- Agricultural Catchments Programme, Teagasc, Wexford, Ireland; School of Environmental & Biological Sciences, University College Dublin, Dublin, Ireland.
| | - P Jordan
- School of Environmental Sciences, University of Ulster, Coleraine, N. Ireland, United Kingdom.
| | - P-E Mellander
- Agricultural Catchments Programme, Teagasc, Wexford, Ireland.
| | - M Kelly-Quinn
- School of Environmental & Biological Sciences, University College Dublin, Dublin, Ireland.
| | - D P Wall
- Environmental Research Centre, Teagasc, Wexford, Ireland.
| | - P N C Murphy
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland.
| | - A R Melland
- National Centre for Engineering in Agriculture, University of Southern Queensland, Toowoomba, Australia.
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Lefrancq M, Payraudeau S, García Verdú AJ, Maillard E, Millet M, Imfeld G. Fungicides transport in runoff from vineyard plot and catchment: contribution of non-target areas. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:4871-4882. [PMID: 23807556 DOI: 10.1007/s11356-013-1866-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/23/2013] [Indexed: 06/02/2023]
Abstract
Surface runoff and erosion during the course of rainfall events are major processes of pesticides transport from agricultural land to aquatic ecosystem. These processes are generally evaluated either at the plot or the catchment scale. Here, we compared at both scales the transport and partitioning in runoff water of two widely used fungicides, i.e., kresoxim-methyl (KM) and cyazofamid (CY). The objective was to evaluate the relationship between fungicides runoff from the plot and from the vineyard catchment. The results show that seasonal exports for KM and CY at the catchment were larger than those obtained at the plot. This underlines that non-target areas within the catchment largely contribute to the overall load of runoff-associated fungicides. Estimations show that 85 and 62 % of the loads observed for KM and CY at the catchment outlet cannot be explained by the vineyard plots. However, the partitioning of KM and CY between three fractions, i.e., the suspended solids (>0.7 μm) and two dissolved fractions (i.e., between 0.22 and 0.7 µm and <0.22 µm) in runoff water was similar at both scales. KM was predominantly detected below 0.22 μm, whereas CY was mainly detected in the fraction between 0.22 and 0.7 μm. Although KM and CY have similar physicochemical properties and are expected to behave similarly, our results show that their partitioning between two fractions of the dissolved phase differs largely. It is concluded that combined observations of pesticide runoff at both the catchment and the plot scales enable to evaluate the sources areas of pesticide off-site transport.
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Affiliation(s)
- Marie Lefrancq
- Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), University of Strasbourg/ENGEES, UMR 7517 CNRS, 1 rue Blessig, 67084, Strasbourg CEDEX, France
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