title: Pollution of surface waters by metalaxyl and nitrate from non-point sources.
abstract: The mobility of contaminants in soil is highly dependent upon the characteristics of the contaminant chemical and the properties of the soil. In order to explore these relationships, the district of A Limia (Galicia, NW Spain) was selected as the study area--a cropland devoted to growing potatoes, where the soil had been managed intensively over the last 50 years. The soil was characterised by low slopes with the water table located very close to the soil surface. Our aim was to study the influence of high and intensive crop production on the water bodies and non-point source contamination, with a particular focus on metalaxyl and nitrate. The highest concentrations of metalaxyl occurred when rainfalls were low and in zones of the study area where natural hydrology was significantly altered by numerous drainage canals. The spatial and temporal distributions of the nitrate also showed a high variability, with the interaction between seasons and sampling area being the most significant factor in explaining the levels found.
authors.affiliation: Soil and Agricultural Science Group, Plant Biology and Soil Science Department, Science Faculty, University of Vigo, Ourense Campus, 32004 Ourense, Spain.
authors.forename: Alipio
authors.initials: A
authors.lastname: Bermúdez-Couso
authors.forename: David
authors.initials: D
authors.lastname: Fernández-Calviño
authors.forename: Manuel Ali
authors.initials: MA
authors.lastname: Álvarez-Enjo
authors.forename: Jesús
authors.initials: J
authors.lastname: Simal-Gándara
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Nóvoa-Muñoz
authors.forename: Manuel
authors.initials: M
authors.lastname: Arias-Estévez
mesh_terms: D000383:Agriculture / Q000379:methods; D000409:Alanine / Q000031:analogs & derivatives* / Q000032:analysis; D000704:Analysis of Variance; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D060587:Groundwater / Q000032:analysis*; D009566:Nitrates / Q000032:analysis*; D011891:Rain; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009566:Nitrates; D012987:Soil; D014874:Water Pollutants, Chemical; C028175:metalaxyl; D000409:Alanine
keywords: Metalaxyl; Nitrate; Non-point sources; Pollution; Surface waters