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Josemiguel Sanchezperez - One of the best experts on this subject based on the ideXlab platform.
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fluvial transport of suspended sediment and organic carbon during flood events in a large Agricultural Catchment in southwest france
Hydrological Processes, 2011Co-Authors: Chantha Oeurng, Eric Maneux, Josemiguel Sanchezperez, Sabine Sauvage, Henri Etcheber, Alexandra CoynelAbstract:Water draining from a large Agricultural Catchment of 1 110 km2 in southwest France was sampled over an 18-month period to determine the temporal variability in suspended sediment (SS) and dissolved (DOC) and particulate organic carbon (POC) transport during flood events, with quantification of fluxes and controlling factors, and to analyze the relationships between discharge and SS, DOC and POC. A total of 15 flood events were analyzed, providing extensive data on SS, POC and DOC during floods. There was high variability in SS, POC and DOC transport during different seasonal floods, with SS varying by event from 513 to 41 750 t; POC from 12 to 748 t and DOC from 9 to 218 t. Overall, 76 and 62% of total fluxes of POC and DOC occurred within 22% of the study period. POC and DOC export from the Save Catchment amounted to 3090 t and 1240 t, equivalent to 1·8 t km−2 y−1 and 0·7 t km−2 y−1, respectively. Statistical analyses showed that total precipitation, flood discharge and total water yield were the major factors controlling SS, POC and DOC transport from the Catchment. The relationships between SS, POC and DOC and discharge over temporal flood events resulted in different hysteresis patterns, which were used to deduce dissolved and particulate origins. In both clockwise and anticlockwise hysteresis, POC mainly followed the same patterns as discharge and SS. The DOC-discharge relationship was mainly characterized by alternating clockwise and anticlockwise hysteresis due to dilution effects of water originating from different sources in the whole Catchment.
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assessment of hydrology sediment and particulate organic carbon yield in a large Agricultural Catchment using the swat model
Journal of Hydrology, 2011Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:Summary The Soil and Water Assessment Tool (SWAT, 2005) was used to simulate discharge and sediment transport at daily time steps within the intensively farmed Save Catchment in south-west France (1110 km 2 ). The SWAT model was applied to evaluate Catchment hydrology and sediment and associated particulate organic carbon yield using historical flow and meteorological data for a 10-years (January 1999–March 2009). Daily data on sediment (27 months, January 2007–March 2009) and particular organic carbon (15 months, January 2008–March 2009) were used to calibrate the model. Data on management practices (crop rotation, planting date, fertiliser quantity and irrigation) were included in the model during the simulation period of 10 years. Simulated daily discharge, sediment and particulate carbon values matched the observed values satisfactorily. The model predicted that mean annual Catchment precipitation for the total study period (726 mm) was partitioned into evapotranspiration (78.3%), percolation/groundwater recharge (14.1%) and abstraction losses (0.5%), yielding 7.1% surface runoff. Simulated mean total water yield for the whole simulation period amounted to 138 mm, comparable to the observed value of 136 mm. Simulated annual sediment yield ranged from 4.3 t km −2 y −1 to 110 t km −2 y −1 (annual mean of 48 t km −2 y −1 ). Annual yield of particulate organic carbon ranged from 0.1 t km −2 y −1 to 2.8 t km −2 y −1 (annual mean of 1.2 t km −2 y −1 ). Thus, the highest annual sediment and particulate carbon yield represented 25 times the minimum annual yield. However, the highest annual water yield represented five times the minimum (222 mm and 51 mm, respectively). An empirical correlation between annual water yield and annual sediment and organic carbon yield was developed for this Agricultural Catchment. Potential source areas of erosion were also identified with the model. The range of the annual contributing erosive zones varied spatially from 0.1 to 6 t ha −1 according to the slope and Agricultural practices at the Catchment scale.
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temporal variability of nitrate transport through hydrological response during flood events within a large Agricultural Catchment in south west france
Science of The Total Environment, 2010Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:The temporal variability of nitrate transport was monitored continuously in a large Agricultural Catchment, the 1110 km2 Save Catchment in south-west France, from January 2007 to June 2009. The overall aim was to analyse the temporal transport of nitrate through hydrological response during flood events in the Catchment. Nitrate loads and hysteresis were also analysed and the relationships between nitrate and hydro-climatological variables within flood events were determined. During the study period, 19 flood events were analysed using extensive datasets obtained by manual and automatic sampling. ThemaximumNO3 − concentration during flood varied from 8.2 mg l−1 to 41.1 mg l−1 with flood discharge from 6.75 m3 s−1 to 112.60 m3 s−1. The annual NO3 − loads in 2007 and 2008 amounted to 2514 t and 3047 t, respectively, with average specific yield of 2.5 tkm−12 yr−1. The temporal transport of nitrate loads during different seasonal flood events varied from 12 t to 909 t. Nitrate transport during flood events amounted to 1600 t (64% of annual load; 16% of annual duration) in 2007 and 1872 t (62% of annual load; 20% of annual duration) in 2008. The level of peak discharge during flood events did not control peak nitrate concentrations, since similar nitrate peaks were produced by different peak discharges. Statistically strong correlations were found between nitrate transport and total precipitation, flood duration, peak discharge and total water yield. These four variables may be the main factors controlling nitrate export from the Save Catchment. The relationship between nitrate and discharge (hysteresis patterns) investigated through flood events in this study was mainly dominated by anticlockwise behaviour.
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dynamics of suspended sediment transport and yield in a large Agricultural Catchment southwest france
Earth Surface Processes and Landforms, 2010Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:The dynamics of suspended sediment transport were monitored continuously in a large Agricultural Catchment in southwest France from January 2007 to March 2009. The objective of this paper is to analyse the temporal variability in suspended sediment transport and yield in that Catchment. Analyses were also undertaken to assess the relationships between precipitation, discharge and suspended sediment transport, and to interpret sediment delivery processes using suspended sediment-discharge hysteresis patterns. During the study period, we analysed 17 flood events, with high resolution suspended sediment data derived from continuous turbidity and automatic sampling. The results revealed strong seasonal, annual and inter-annual variability in suspended sediment transport. Sediment was strongly transported during spring, when frequent flood events of high magnitude and intensity occurred. Annual sediment transport in 2007 yielded 16 614 tonnes, representing 15 t km−2 (85% of annual load transport during floods for 16% of annual duration), while the 2008 sediment yield was 77 960 tonnes, representing 70 t km−2 (95% of annual load transport during floods for 20% of annual duration). Analysis of the relationships between precipitation, discharge and suspended sediment transport showed that there were significant correlations between total precipitation, peak discharge, total water yield, flood intensity and sediment variables during the flood events, but no relationship with antecedent conditions. Flood events were classified in relation to suspended sediment concentration (SSC)–discharge hysteretic loops, complemented with temporal dynamics of SSC–discharge ranges during rising and falling flow. The hysteretic shapes obtained for all flood events reflected the distribution of probable sediment sources throughout the Catchment. Regarding the sediment transport during all flood events, clockwise hysteretic loops represented 68% from river deposited sediments and nearby source areas, anticlockwise 29% from distant source areas, and simultaneity of SSC and discharge 3%. Copyright © 2010 John Wiley & Sons, Ltd.
Sabine Sauvage - One of the best experts on this subject based on the ideXlab platform.
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new insight into pesticide partition coefficient kd for modelling pesticide fluvial transport application to an Agricultural Catchment in south western france
Chemosphere, 2014Co-Authors: Laurie Boithias, Séverine Jean, Jeanluc Probst, Sabine Sauvage, Georges Merlina, Jose Miguel Sanchez PerezAbstract:Pesticides applied on crops are leached with rainfall to groundwater and surface water. They threat the aquatic environment and may render water unfit for human consumption. Pesticide partitioning is one of the pesticide fate processes in the environment that should be properly formalised in pesticide fate models. Based on the analysis of 7 pesticide molecules (alachlor, atrazine, atrazine's transformation product deethylatrazine or DEA, isoproturon, tebuconazole and trifluralin) sampled from July 2009 to October 2010 at the outlet of the river Save (south-western France), the objectives of this study were (1) to check which of the environmental factors (discharge, pH, concentrations of total suspended matter (TSM), dissolved organic carbon (DOC) and particulate organic carbon (POC) could control the pesticide sorption dynamic, and (2) to establish a relationship between environmental factors, the partition coefficient Kd and the octanol/water distribution coefficient Kow. The comparison of physico-chemical parameters values during low flow and high flow shows that discharge, TSM and POC are the factors most likely controlling the pesticide sorption processes in the Save river network, especially for lower values of TSM (below 13 mg L-1). We therefore express Kd depending on the widely literature-related variable Kow and on the commonly simulated variable TSM concentration. The equation can be implemented in any model describing the fluvial transport and fate of pesticides in both dissolved and sorbed phases, thus, Kd becomes a variable in time and space. The Kd calculation method can be applied to a wide range of Catchments and organic contaminants.
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occurrence of metolachlor and trifluralin losses in the save river Agricultural Catchment during floods
Journal of Hazardous Materials, 2011Co-Authors: Laurie Boithias, Jeanluc Probst, Sabine Sauvage, Georges Merlina, Lobat Taghavi, Jose Miguel Sanchez PerezAbstract:Abstract Rising pesticide levels in streams draining intensively managed Agricultural land have a detrimental effect on aquatic ecosystems and render water unfit for human consumption. The Soil and Water Assessment Tool (SWAT) was applied to simulate daily pesticide transfer at the outlet from an Agriculturally intensive Catchment of 1110 km 2 (Save river, south-western France). SWAT reliably simulated both dissolved and sorbed metolachlor and trifluralin loads and concentrations at the Catchment outlet from 1998 to 2009. On average, 17 kg of metolachlor and 1 kg of trifluralin were exported at outlet each year, with annual rainfall variations considered. Surface runoff was identified as the preferred pathway for pesticide transfer, related to the good correlation between suspended sediment exportation and pesticide, in both soluble and sorbed phases. Pesticide exportation rates at Catchment outlet were less than 0.1% of the applied amount. At outlet, SWAT hindcasted that (i) 61% of metolachlor and 52% of trifluralin were exported during high flows and (ii) metolachlor and trifluralin concentrations exceeded European drinking water standards of 0.1 μg L −1 for individual pesticides during 149 (3.6%) and 17 (0.4%) days of the 1998–2009 period respectively. SWAT was shown to be a promising tool for assessing large Catchment river network pesticide contamination in the event of floods but further useful developments of pesticide transfers and partition coefficient processes would need to be investigated.
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fluvial transport of suspended sediment and organic carbon during flood events in a large Agricultural Catchment in southwest france
Hydrological Processes, 2011Co-Authors: Chantha Oeurng, Eric Maneux, Josemiguel Sanchezperez, Sabine Sauvage, Henri Etcheber, Alexandra CoynelAbstract:Water draining from a large Agricultural Catchment of 1 110 km2 in southwest France was sampled over an 18-month period to determine the temporal variability in suspended sediment (SS) and dissolved (DOC) and particulate organic carbon (POC) transport during flood events, with quantification of fluxes and controlling factors, and to analyze the relationships between discharge and SS, DOC and POC. A total of 15 flood events were analyzed, providing extensive data on SS, POC and DOC during floods. There was high variability in SS, POC and DOC transport during different seasonal floods, with SS varying by event from 513 to 41 750 t; POC from 12 to 748 t and DOC from 9 to 218 t. Overall, 76 and 62% of total fluxes of POC and DOC occurred within 22% of the study period. POC and DOC export from the Save Catchment amounted to 3090 t and 1240 t, equivalent to 1·8 t km−2 y−1 and 0·7 t km−2 y−1, respectively. Statistical analyses showed that total precipitation, flood discharge and total water yield were the major factors controlling SS, POC and DOC transport from the Catchment. The relationships between SS, POC and DOC and discharge over temporal flood events resulted in different hysteresis patterns, which were used to deduce dissolved and particulate origins. In both clockwise and anticlockwise hysteresis, POC mainly followed the same patterns as discharge and SS. The DOC-discharge relationship was mainly characterized by alternating clockwise and anticlockwise hysteresis due to dilution effects of water originating from different sources in the whole Catchment.
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assessment of hydrology sediment and particulate organic carbon yield in a large Agricultural Catchment using the swat model
Journal of Hydrology, 2011Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:Summary The Soil and Water Assessment Tool (SWAT, 2005) was used to simulate discharge and sediment transport at daily time steps within the intensively farmed Save Catchment in south-west France (1110 km 2 ). The SWAT model was applied to evaluate Catchment hydrology and sediment and associated particulate organic carbon yield using historical flow and meteorological data for a 10-years (January 1999–March 2009). Daily data on sediment (27 months, January 2007–March 2009) and particular organic carbon (15 months, January 2008–March 2009) were used to calibrate the model. Data on management practices (crop rotation, planting date, fertiliser quantity and irrigation) were included in the model during the simulation period of 10 years. Simulated daily discharge, sediment and particulate carbon values matched the observed values satisfactorily. The model predicted that mean annual Catchment precipitation for the total study period (726 mm) was partitioned into evapotranspiration (78.3%), percolation/groundwater recharge (14.1%) and abstraction losses (0.5%), yielding 7.1% surface runoff. Simulated mean total water yield for the whole simulation period amounted to 138 mm, comparable to the observed value of 136 mm. Simulated annual sediment yield ranged from 4.3 t km −2 y −1 to 110 t km −2 y −1 (annual mean of 48 t km −2 y −1 ). Annual yield of particulate organic carbon ranged from 0.1 t km −2 y −1 to 2.8 t km −2 y −1 (annual mean of 1.2 t km −2 y −1 ). Thus, the highest annual sediment and particulate carbon yield represented 25 times the minimum annual yield. However, the highest annual water yield represented five times the minimum (222 mm and 51 mm, respectively). An empirical correlation between annual water yield and annual sediment and organic carbon yield was developed for this Agricultural Catchment. Potential source areas of erosion were also identified with the model. The range of the annual contributing erosive zones varied spatially from 0.1 to 6 t ha −1 according to the slope and Agricultural practices at the Catchment scale.
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temporal variability of nitrate transport through hydrological response during flood events within a large Agricultural Catchment in south west france
Science of The Total Environment, 2010Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:The temporal variability of nitrate transport was monitored continuously in a large Agricultural Catchment, the 1110 km2 Save Catchment in south-west France, from January 2007 to June 2009. The overall aim was to analyse the temporal transport of nitrate through hydrological response during flood events in the Catchment. Nitrate loads and hysteresis were also analysed and the relationships between nitrate and hydro-climatological variables within flood events were determined. During the study period, 19 flood events were analysed using extensive datasets obtained by manual and automatic sampling. ThemaximumNO3 − concentration during flood varied from 8.2 mg l−1 to 41.1 mg l−1 with flood discharge from 6.75 m3 s−1 to 112.60 m3 s−1. The annual NO3 − loads in 2007 and 2008 amounted to 2514 t and 3047 t, respectively, with average specific yield of 2.5 tkm−12 yr−1. The temporal transport of nitrate loads during different seasonal flood events varied from 12 t to 909 t. Nitrate transport during flood events amounted to 1600 t (64% of annual load; 16% of annual duration) in 2007 and 1872 t (62% of annual load; 20% of annual duration) in 2008. The level of peak discharge during flood events did not control peak nitrate concentrations, since similar nitrate peaks were produced by different peak discharges. Statistically strong correlations were found between nitrate transport and total precipitation, flood duration, peak discharge and total water yield. These four variables may be the main factors controlling nitrate export from the Save Catchment. The relationship between nitrate and discharge (hysteresis patterns) investigated through flood events in this study was mainly dominated by anticlockwise behaviour.
Chantha Oeurng - One of the best experts on this subject based on the ideXlab platform.
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fluvial transport of suspended sediment and organic carbon during flood events in a large Agricultural Catchment in southwest france
Hydrological Processes, 2011Co-Authors: Chantha Oeurng, Eric Maneux, Josemiguel Sanchezperez, Sabine Sauvage, Henri Etcheber, Alexandra CoynelAbstract:Water draining from a large Agricultural Catchment of 1 110 km2 in southwest France was sampled over an 18-month period to determine the temporal variability in suspended sediment (SS) and dissolved (DOC) and particulate organic carbon (POC) transport during flood events, with quantification of fluxes and controlling factors, and to analyze the relationships between discharge and SS, DOC and POC. A total of 15 flood events were analyzed, providing extensive data on SS, POC and DOC during floods. There was high variability in SS, POC and DOC transport during different seasonal floods, with SS varying by event from 513 to 41 750 t; POC from 12 to 748 t and DOC from 9 to 218 t. Overall, 76 and 62% of total fluxes of POC and DOC occurred within 22% of the study period. POC and DOC export from the Save Catchment amounted to 3090 t and 1240 t, equivalent to 1·8 t km−2 y−1 and 0·7 t km−2 y−1, respectively. Statistical analyses showed that total precipitation, flood discharge and total water yield were the major factors controlling SS, POC and DOC transport from the Catchment. The relationships between SS, POC and DOC and discharge over temporal flood events resulted in different hysteresis patterns, which were used to deduce dissolved and particulate origins. In both clockwise and anticlockwise hysteresis, POC mainly followed the same patterns as discharge and SS. The DOC-discharge relationship was mainly characterized by alternating clockwise and anticlockwise hysteresis due to dilution effects of water originating from different sources in the whole Catchment.
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assessment of hydrology sediment and particulate organic carbon yield in a large Agricultural Catchment using the swat model
Journal of Hydrology, 2011Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:Summary The Soil and Water Assessment Tool (SWAT, 2005) was used to simulate discharge and sediment transport at daily time steps within the intensively farmed Save Catchment in south-west France (1110 km 2 ). The SWAT model was applied to evaluate Catchment hydrology and sediment and associated particulate organic carbon yield using historical flow and meteorological data for a 10-years (January 1999–March 2009). Daily data on sediment (27 months, January 2007–March 2009) and particular organic carbon (15 months, January 2008–March 2009) were used to calibrate the model. Data on management practices (crop rotation, planting date, fertiliser quantity and irrigation) were included in the model during the simulation period of 10 years. Simulated daily discharge, sediment and particulate carbon values matched the observed values satisfactorily. The model predicted that mean annual Catchment precipitation for the total study period (726 mm) was partitioned into evapotranspiration (78.3%), percolation/groundwater recharge (14.1%) and abstraction losses (0.5%), yielding 7.1% surface runoff. Simulated mean total water yield for the whole simulation period amounted to 138 mm, comparable to the observed value of 136 mm. Simulated annual sediment yield ranged from 4.3 t km −2 y −1 to 110 t km −2 y −1 (annual mean of 48 t km −2 y −1 ). Annual yield of particulate organic carbon ranged from 0.1 t km −2 y −1 to 2.8 t km −2 y −1 (annual mean of 1.2 t km −2 y −1 ). Thus, the highest annual sediment and particulate carbon yield represented 25 times the minimum annual yield. However, the highest annual water yield represented five times the minimum (222 mm and 51 mm, respectively). An empirical correlation between annual water yield and annual sediment and organic carbon yield was developed for this Agricultural Catchment. Potential source areas of erosion were also identified with the model. The range of the annual contributing erosive zones varied spatially from 0.1 to 6 t ha −1 according to the slope and Agricultural practices at the Catchment scale.
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temporal variability of nitrate transport through hydrological response during flood events within a large Agricultural Catchment in south west france
Science of The Total Environment, 2010Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:The temporal variability of nitrate transport was monitored continuously in a large Agricultural Catchment, the 1110 km2 Save Catchment in south-west France, from January 2007 to June 2009. The overall aim was to analyse the temporal transport of nitrate through hydrological response during flood events in the Catchment. Nitrate loads and hysteresis were also analysed and the relationships between nitrate and hydro-climatological variables within flood events were determined. During the study period, 19 flood events were analysed using extensive datasets obtained by manual and automatic sampling. ThemaximumNO3 − concentration during flood varied from 8.2 mg l−1 to 41.1 mg l−1 with flood discharge from 6.75 m3 s−1 to 112.60 m3 s−1. The annual NO3 − loads in 2007 and 2008 amounted to 2514 t and 3047 t, respectively, with average specific yield of 2.5 tkm−12 yr−1. The temporal transport of nitrate loads during different seasonal flood events varied from 12 t to 909 t. Nitrate transport during flood events amounted to 1600 t (64% of annual load; 16% of annual duration) in 2007 and 1872 t (62% of annual load; 20% of annual duration) in 2008. The level of peak discharge during flood events did not control peak nitrate concentrations, since similar nitrate peaks were produced by different peak discharges. Statistically strong correlations were found between nitrate transport and total precipitation, flood duration, peak discharge and total water yield. These four variables may be the main factors controlling nitrate export from the Save Catchment. The relationship between nitrate and discharge (hysteresis patterns) investigated through flood events in this study was mainly dominated by anticlockwise behaviour.
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dynamics of suspended sediment transport and yield in a large Agricultural Catchment southwest france
Earth Surface Processes and Landforms, 2010Co-Authors: Chantha Oeurng, Josemiguel Sanchezperez, Sabine SauvageAbstract:The dynamics of suspended sediment transport were monitored continuously in a large Agricultural Catchment in southwest France from January 2007 to March 2009. The objective of this paper is to analyse the temporal variability in suspended sediment transport and yield in that Catchment. Analyses were also undertaken to assess the relationships between precipitation, discharge and suspended sediment transport, and to interpret sediment delivery processes using suspended sediment-discharge hysteresis patterns. During the study period, we analysed 17 flood events, with high resolution suspended sediment data derived from continuous turbidity and automatic sampling. The results revealed strong seasonal, annual and inter-annual variability in suspended sediment transport. Sediment was strongly transported during spring, when frequent flood events of high magnitude and intensity occurred. Annual sediment transport in 2007 yielded 16 614 tonnes, representing 15 t km−2 (85% of annual load transport during floods for 16% of annual duration), while the 2008 sediment yield was 77 960 tonnes, representing 70 t km−2 (95% of annual load transport during floods for 20% of annual duration). Analysis of the relationships between precipitation, discharge and suspended sediment transport showed that there were significant correlations between total precipitation, peak discharge, total water yield, flood intensity and sediment variables during the flood events, but no relationship with antecedent conditions. Flood events were classified in relation to suspended sediment concentration (SSC)–discharge hysteretic loops, complemented with temporal dynamics of SSC–discharge ranges during rising and falling flow. The hysteretic shapes obtained for all flood events reflected the distribution of probable sediment sources throughout the Catchment. Regarding the sediment transport during all flood events, clockwise hysteretic loops represented 68% from river deposited sediments and nearby source areas, anticlockwise 29% from distant source areas, and simultaneity of SSC and discharge 3%. Copyright © 2010 John Wiley & Sons, Ltd.
Jenny Kreuger - One of the best experts on this subject based on the ideXlab platform.
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spatial and temporal patterns of pesticide concentrations in streamflow drainage and runoff in a small swedish Agricultural Catchment
Science of The Total Environment, 2018Co-Authors: Maria Sandin, Kristin Piikki, Nicholas Jarvis, Mats Larsbo, Kevin Bishop, Jenny KreugerAbstract:A better understanding of the dominant source areas and transport pathways of pesticide losses to surface water is needed for targeting mitigation efforts in a more cost-effective way. To this end, we monitored pesticides in surface water in an Agricultural Catchment typical of one of the main crop production regions in Sweden. Three small sub-Catchments (88-242ha) were selected for water sampling based on a high-resolution digital soil map developed from proximal sensing methods and soil sampling; one sub-Catchment had a high proportion of clay soils, another was dominated by coarse sandy soils while the third comprised a mix of soil types. Samples were collected from the stream, from field drains discharging into the stream and from within-field surface runoff during spring and early summer in three consecutive years. These samples were analyzed by LC-MS/MS for 99 compounds, including most of the polar and semi-polar pesticides frequently used in Swedish agriculture. Information on pesticide applications (products, doses and timing) was obtained from annual interviews with the farmers. There were clear and consistent differences in pesticide occurrence in the stream between the three sub-Catchments, with both the numbers of detected compounds and concentrations being the largest in the area with a high proportion of clay soils and with very few detections in the sandy sub-Catchment. Macropore flow to drains was most likely the dominant loss pathway in the studied area. Many of the compounds that were detected in drainage and stream water samples had not been applied for several years. This suggests that despite the predominant role of fast flow pathways in determining losses to the stream, long-term storage along the transport pathways also occurs, presumably in subsoil horizons where degradation is slow.
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pesticides in stream water within an Agricultural Catchment in southern sweden 1990 1996
Science of The Total Environment, 1998Co-Authors: Jenny KreugerAbstract:Abstract Pesticide loss to stream water was studied in a small Agricultural Catchment in southern Sweden during the period 1990–1996. A total of 38 pesticides were detected in water samples, including 30 herbicides, four fungicides, three insecticides and one metabolite of one of the herbicides. Concentrations of pesticides in stream water were observed throughout the sampling periods. Peak concentrations occurred during the spraying seasons and following runoff events. Daily average concentrations sometimes varied by one order of magnitude from one day to another. Pesticides were also found in water samples as a result of incautious actions during handling and application procedures. Concentrations were lower at the outlet of the Catchment area when the water had passed an open part of the stream, compared to concentrations detected in discharge from a culvert system upstream. This was largely a result of dilution from groundwater intrusion during low-flow periods. Sampling at different sites along the culvert demonstrated that the small village situated in the Catchment did not contribute to pesticide findings in the culvert discharge. Wind drift had little influence on stream-water quality. Pesticide application for weed control in farmyards resulted in a substantial contribution to the pesticide load in stream water. Pesticides were persistent in the discharge throughout the winter and originated from both autumn and spring applications, as well as from farmyard application. Some autumn applied pesticides prevailed in stream flow during the following summer. Total amounts of pesticides lost in stream flow during May–September each year varied between 0.5 and 2.8 kg during the 7-year period, corresponding to ∼0.1% of the applied amount. Losses of single pesticides were generally less than 0.3% of the applied amount during individual years. Pesticides from Agricultural applications in the Catchment constituted, on average, 82% of the total transported amount lost during May–September each year, of which 2% was from autumn application the previous year. There was an overall correlation between amounts used in the Catchment and occurrence in the water samples. The total pesticide load in water decreased markedly during the course of the investigation, in accordance with decreased amounts applied during spring and early summer. The results indicate that concentrations of some pesticides entering head-water streams in Agricultural areas are close to, and during certain time periods even above those levels demonstrated as having an impact on the aquatic flora and fauna.
Christophe Mouvet - One of the best experts on this subject based on the ideXlab platform.
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Agricultural diffuse pollution in a chalk aquifer trois fontaines france influence of pesticide properties and hydrodynamic constraints
Journal of Hydrology, 2008Co-Authors: Nicole Baran, Michel Lepiller, Christophe MouvetAbstract:The characterization of the transfer of pesticides to and in groundwater is essential for effective water resource management. Intensive monitoring, from October 1989 to May 2006, of a weakly karstified chalk aquifer system in a 50 km2 Agricultural Catchment, enabled the characterization of the temporal variability of pesticide concentrations in the groundwater of the main outlet. Atrazine and its metabolite deethylatrazine were quantified 394 and 393 times in 476 samples with concentrations ranging from the quantification limit (0.025 μg L−1) to 5.3 and 1.86 μg L−1, respectively. This common presence, compared to the rare detections of isoproturon (in 108 of 476 samples), the pesticide most widely used in the Catchment during at least the past decade, highlighted the significant effect of pesticide properties in the time series of concentrations observed in the groundwater. The use of geochemical tracers (nitrate, chloride) analysed in the groundwater and the hydrodynamic monitoring of the system (discharge, water levels) enabled identification of various infiltration mechanisms governing the functioning of the system. The hydrodynamic study showing that the relative contribution of the infiltration mechanisms varies with time, made it possible to explain major variations observed in the pesticide-concentration time series recorded at the spring.