Journal Title
Title of Journal: Hydrogeol J
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Abbravation: Hydrogeology Journal
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Publisher
Springer-Verlag
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Authors: Josh E Moncrieff Laurence R Bentley Heyddy Calderón Palma
Publish Date: 2007/10/23
Volume: 16, Issue: 1, Pages: 183-197
Abstract
Nicaragua’s LeónChinandega aquifer has seen extensive contamination by persistent organochlorine pesticides applied over decades of intensive agricultural activity Models of flow and transport of a 330 km2 subregion of the aquifer were developed to test conceptual models of contaminant transport to constrain the value of certain key transport parameters and to investigate contaminationrelated concerns raised in past studies To support these models a variety of hydrogeologic and geochemical data were collected It was concluded that the organochlorine pesticides seen in groundwater originate in soils and are transported to the water table through widespread preferential flow through shortcutting around wells or through windblown particles delivered to poorly protected handdug wells The distribution coefficient K d of these pesticides is estimated to be between 01 and 100 ml/g and the concentration of pesticides being delivered to the water table is estimated to be between 102 and 105 ng/L It was found that the distribution and concentration of pesticides in the aquifer would be affected by an increase in groundwater abstraction within the regionL’aquifère du LeónChinandega au Nicaragua a été soumis à des contaminations étendues par des pesticides organochlorés persistants qui ont été répandus pendant des dizaines d’années d’agriculture intensive Des modèles d’écoulement et de transport d’une sousrégion de 330 km2 de l’aquifère ont été construits pour tester des modèles conceptuels du transport de contaminants pour contraindre la valeur de certains paramètres de transport clefs et pour étudier les problèmes liés au transport de contaminations qui avaient été rencontrés lors d’études précédentes Différents types de données hydrogéologiques et géochimiques ont été collectés pour réaliser ces modèles La conclusion montre que les pesticides organochlorés rencontrés dans les eaux souterraines proviennent des sols et qu’ils sont transportés jusqu’à l’aquifère via de grandes zones d’écoulement préférentiel via des raccourcis hydrauliques autour des puits ou encore via des particules emportées par le vent et tombées dans des puits creusés à la main et mal protégés Le coefficient de distribution K d de ces pesticides est estimé entre 01 et 100 ml/g et la concentration de pesticides arrivant dans la nappe est estimée entre 102 et 105 ng/L L’étude a montré qu’une augmentation des prélèvements d’eau souterraine dans la région aurait un impact sur la distribution et la concentration des pesticides dans l’aquifèreEl acuifero LeónChinandega Nicaragua presenta una contaminación extensiva por la aplicación de plaguicidas organoclorados en la agricultura intensiva durante décadas Se han desarrollado modelos de flujo y transporte de una subregión del acuífero de 330 km2 para comprobar los modelos conceptuales del transporte de contaminantes estimar los valores de ciertos parámetros clave de transporte e investigar los temas relacionados con la contaminación en estudios anteriores Para elaborar estos modelos se recogió una variedad de datos hidrogeológicos y geoquímicos Se ha concluido que los plaguicidas organoclorados presentes en el agua subterránea se originan en el suelo y son transportados hacia el nivel freático a través de flujos preferentes generalizados a través de cortes alrededor de los pozos o a través de partículas transportadas por el viento depositadas en pozos excavados a mano con poca protección El coeficiente de distribución K d de estos plaguicidas se ha estimado entre 01 y 100 ml/g y la concentración de plaguicidas que sale hacia el nivel freático se estima que puede estar entre 102 y 105 ng/L Se ha concluido que el incremento de la extracción de aguas subterráneas dentro de la región afectaría la distribución y concentración de plaguicidas en el acuíferoThis project was undertaken with the support of the Department of Geology and Geophysics at the University of Calgary Canada and the Centro para la Investigación en Recursos Acuáticos de Nicaragua at the Universidad Nacional Autónoma de Nicaragua It was funded by the Canadian International Development Agency through the Central American Water Resource Management Network the International Institute for Sustainable Development and the Natural Sciences and Engineering Research Council of Canada Also gratefully acknowledged are the contributions of the Centro de Investigaciones Geocientíficas at the Universidad Nacional Autónoma de Nicaragua the Municipality of Posoltega Nicaragua Sugar Estates Limited and the Instituto Nicaragüense de Estudios Territoriales
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- Influence of rainfall on the deformation and stability of a slope in overconsolidated clays: a case study
- Transport and deposition of suspended particles in saturated porous media: hydrodynamic effect
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- Numerical modeling of stress-permeability coupling in rough fractures
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- Is self-regulation a myth? Case study on Spanish groundwater user associations and the role of higher-level authorities
- Reply to comment on “Geochemical heterogeneity and isotope geochemistry of natural attenuation processes in a gasoline-contaminated aquifer at the Hnevice site, Czech Republic”: report published in Hydrogeology Journal (2007) 15: 961-976, by Barbora Topinkova, Kamil Nesetril, Josef Datel, Ondrej Nol, Petr Hosl
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- Effects of climate change on groundwater resources at Shelter Island, New York State, USA
- Simulated impacts of artificial groundwater recharge and discharge on the source area and source volume of an Atlantic Coastal Plain stream, Delaware, USA
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