Stream Nitrate Variations Explained by Ground Water Head Fluctuations in a Pyrite-Bearing Aquifer

Autor: F. Rouault, Catherine Grimaldi, Nicolas Gilliet, S. Derosch, Valérie Viaud, L. Carteaux, F. Massa, Y. Fauvel, A. Regeard
Přispěvatelé: Sol Agro et hydrosystème Spatialisation (SAS), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
Jazyk: angličtina
Rok vydání: 2004
Předmět:
Environmental Engineering
Watershed
Iron
0207 environmental engineering
Drainage basin
Context (language use)
Aquifer
02 engineering and technology
010501 environmental sciences
Management
Monitoring
Policy and Law
Sulfides
01 natural sciences
chemistry.chemical_compound
Nitrate
Rivers
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry
Spring (hydrology)
Water Movements
[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology
020701 environmental engineering
Waste Management and Disposal
ComputingMilieux_MISCELLANEOUS
0105 earth and related environmental sciences
Water Science and Technology
Hydrology
geography
geography.geographical_feature_category
Nitrates
Water
15. Life on land
Plants
Pollution
6. Clean water
chemistry
13. Climate action
Surface water
Geology
Groundwater
Environmental Monitoring
Zdroj: Journal of Environmental Quality
Journal of Environmental Quality, Crop Science Society of America, 2004, 33 (3), pp.994. ⟨10.2134/jeq2004.0994⟩
ResearcherID
ISSN: 0047-2425
1537-2537
DOI: 10.2134/jeq2004.0994⟩
Popis: Understanding the factors determining stream ni- trate variations will lead to the application of water qual- In the context of agricultural nitrogen excesses in northwestern ity protection or restoration measures better adapted France, pyrite-bearing weathered schist aquifers represent important to the various types of functioning of catchment areas. hydrological compartments due to their capacity to eliminate nitrate (NO3). Under oxygen-free conditions, nitrate is reduced simultaneously The inflow from pyrite-bearing aquifers can lower the with the oxidation of pyrite leading to the release of sulfate (SO4 2 ). nitrate content of stream waters. Moreover, ground wa- The aim of the present study is to identify the hydrological conditions ter studies contribute to our knowledge of the exchanges under which the weathered schist ground water influences the stream between surface and ground waters. Such exchanges water chemistry, leading to a decrease in NO3 concentration. We mea- can affect the biological functioning of the "hyporheic sured the ground water head on a small catchment over weathered zone," an active and dynamic ecotone of the stream schist, near the bank and under the streambed, and analyzed the ecosystem (Pionke et al., 1988; Cirmo and McDonnell, chemical composition of the ground water as well as the stream water 1997; Boulton et al., 1998). on both seasonal and storm-event timescales. Using SO4 2 as a tracer The objective is to study the hydrological and geo- of the weathered schist ground water, we showed that ground water chemical dynamics of ground water in a pyrite-bearing inflow caused a decrease of NO3 concentration in the stream during the autumn as well as during storm events in spring and summer. In aquifer, and its influence on lowering the nitrate content summer, the NO3 concentration was controlled by the sources of the in a small stream located in the Armorican Massif. To stream, and in winter by the shallow ground water inflow. The effect this purpose, we measured the hydraulic head of the of the weathered schist ground water on the NO3 depletion remained ground water next to and under the stream, and ana- relatively limited in time. This effect persisted into late autumn as lyzed the chemical composition of the ground water as long as the NO3-rich shallow ground water did not feed the stream. well as the stream water. We were interested in the The duration and intensity of the effect would be extended by decreas- seasonal and interannual variations of these parameters, ing the shallow ground water inflow, which depends on climate as well as well as their episodic variations during storm events. as the presence of landscape features such as hedges and buffer zones. By monitoring the dynamics of ground water head, cou- pled with the use of SO4 2 as a tracer, we attempt to show under which hydrological conditions the chemical com
Databáze: OpenAIRE
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