RESUMEN
Pesticide mineralization and sorption were determined in 75 soil samples from 15 individually drilled holes through the vadose zone along a 28km long transect of the Danish outwash plain. Mineralization of the phenoxyacetic acid herbicide MCPA was high both in topsoils and in most subsoils, while metribuzine and methyltriazine-amine was always low. Organic matter and soil pH was shown to be responsible for sorption of MCPA and metribuzine in the topsoils. The sorption of methyltriazine-amine in topsoil was positively correlated with clay and negatively correlated with the pH of the soil. Sorption of glyphosate was tested also high in the subsoils. One-dimensional MACRO modeling of the concentration of MCPA, metribuzine and methyltriazine-amine at 2m depth calculated that the average concentration of MCPA and methyltriazine-amine in the groundwater was below the administrative limit of 0.1mug/l in all tested profiles while metribuzine always exceeded the 0.1mug/l threshold value.
Asunto(s)
Ácido 2-Metil-4-clorofenoxiacético/análisis , Herbicidas/análisis , Contaminantes del Suelo/análisis , Suelo/análisis , Adsorción , Silicatos de Aluminio , Biodegradación Ambiental , Arcilla , Dinamarca , Monitoreo del Ambiente/métodos , Glicina/análogos & derivados , Glicina/análisis , Concentración de Iones de Hidrógeno , Modelos Estadísticos , Tamaño de la Partícula , Material Particulado , Ríos , Triazinas/análisis , Contaminantes Químicos del Agua/análisis , GlifosatoRESUMEN
The threat to the aquatic environment posed by root zone leaching of estrogens from manure-treated fields has hitherto been overlooked. The steroid hormones 17beta-estradiol (E2) and its degradation product estrone (E1) are of particular environmental concern as both are abundant in slurryfrom pregnant and cycling pigs and both are potential endocrine disruptors (lowest observable effect level (LOEL) 14 and 3.3 ng/L, respectively). The present one-year study examines the transport of E1 and E2 from manure to tile drainage systems at two field sites on structured, loamy soil. The estrogens leached from the root zone to tile drainage water in concentrations exceeding the LOEL for as long as 3 months after application, with the maximum recorded concentration of E1 and E2 being 68.1 and 2.5 ng/ L, respectively. Transport of estrogens from the soil to the aquatic environment was governed by pronounced macropore flow and consequent rapid movement of the estrogens to the tile drains. These findings suggest that the application of manure to structured soils poses a potential contamination risk to the aquatic environment with estrogen, particularly when manure is applied to areas where the majority of streamwater derives from drainage water.