caa a22 4500 477058469 CHVBK 20180405111353.0 cr unu---uuuuu 170330e19961201xx s 000 0 eng 10.1007/BF01872154 doi (NATIONALLICENCE)springer-10.1007/BF01872154 An analytical model for the assessment of pesticide exposure levels in soils and groundwater [Elektronische Daten] [Mohamed Hantush, Miguel Mariño] The movement and degradation of pesticide residues in soils and groundwater are complex processes affected by soil physical, (bio)chemical, and hydrogeological properties, climatic conditions, and agricultural practices. This work presents a physically-based analytical model suitable for long-term predictions of pesticide concentrations in groundwater. The primary interest is to investigate the impact of soil environment, related physical and (bio)chemical processes, especially, volatilization, crop uptake, and agricultural practices on long-term vulnerability of groundwater to contamination by pesticides. The soil is separated into root and intermediate vadose zones, each with uniform properties. Transport in each soil zone is modeled on the basis of complete mixing, by spatial averaging the related point multiphase-transport partial differential equation (i.e., linear-reservoir models). Transport in the aquifer, however, is modeled by a two-dimensional advection-dispersion transport equation, considering adsorption and first-order decay rate. Vaporization in the soil is accounted for by assuming liquid-vapor phase partitioning using Henry's law, and vapor flux (volatilization) from the soil surface is modeled by diffusion through an air boundary layer. Sorption of liquid-phase solutes by crops is described by a linear relationship which is valid for first-order (passive) crop uptake. The model is applied to five pesticides (atrazine, bromacil, chlordane, heptachlor, and lindane), and the potential for pesticide contamination of groundwater is investigated for sandy and clayey soils. Simulation results show that groundwater contamination can be substantially reduced for clayey soil environments, where bio(chemical) degradation and volatilization are most efficient as natural loss pathways for the pesticides. Also, uptake by cross can be a significant mechanism for attenuating exposure levels in ground-water especially in a sandy soil environment, and for relatively persisting pesticides. Further, simulations indicate that changing agricultural practices can have a profound effect on vulnerability of groundwater to mobile and relatively persisting pesticides. Baltzer Science Publishers, 1996 Aquifers nationallicence contaminant transport nationallicence groundwater modeling nationallicence groundwater quality nationallicence solute transport and exchanges nationallicence water pollution nationallicence non-point source nationallicence pesticides nationallicence soil pollution nationallicence volatilization nationallicence crop-root uptake nationallicence Hantush Mohamed Land, Air, and Water Resources, University of California, 95616, Davis, CA, USA aut Mariño Miguel Land, Air, and Water Resources, University of California, 95616, Davis, CA, USA aut Environmental Modeling & Assessment Kluwer Academic Publishers 1/4(1996-12-01), 263-276 1420-2026 1:4<263 1996 1 10666 https://doi.org/10.1007/BF01872154 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01872154 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hantush Mohamed Land, Air, and Water Resources, University of California, 95616, Davis, CA, USA aut NATIONALLICENCE 700 1- Mariño Miguel Land, Air, and Water Resources, University of California, 95616, Davis, CA, USA aut NATIONALLICENCE 773 0- Environmental Modeling & Assessment Kluwer Academic Publishers 1/4(1996-12-01), 263-276 1420-2026 1:4<263 1996 1 10666 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer