A partition-limited model for the plant uptake of organic contaminants from soil and water
A partition-limited model for the plant uptake of organic contaminants from soil and water
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DOI：
10.1021/es0017561
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发表时间：
2001-04-01
影响因子：
11.4
通讯作者：
Manes, M
中科院分区：
文献类型：
--
作者：
Chiou, CT;Sheng, GY;Manes, M
在处理有机污染物从土壤到植物的被动运输时（包括作物），分区有限的模型，其中（i）最大污染物在植物中任何位置的（平衡）浓度通过其在土壤间隙水中的浓度的分配平衡来确定，而这又主要取决于土壤有机质（SOM）的浓度和（ii）接近分配平衡的程度，通过植物水和土壤间隙水中污染物浓度的比值，α（pt）（小于或等于1），取决于土壤水中的污染物进入植物的传输速率和植物污染物水平所需的土壤水溶液的体积，与外部土壤-水相达到平衡。通过合理估计植物有机水成分和污染物与各种植物成分的分配系数，该模型解释了几项已发表的作物污染研究中的α（pt）计算值，包括近平衡值（即，α（pt）类似或等于1），而对于溶解度低得多的污染物，α（pt）值较低;差异归因于溶解度低的化合物在植物脂质和植物水之间的分配系数高得多，这需要更大体积的植物水运输以实现平衡容量。模型分析表明，对于高含水量的植物，植物-水相作为高水溶性污染物的主要水库。相比之下，植物中的脂质，即使是少量的，通常也是高度水不溶性污染物的主要储存库。
In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plant water and soil interstitial water, alpha (pt) (less than or equal to 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of alpha (pt) in several published crop-contamination studies, including near-equilibrium values (i.e., alpha (pt) similar or equal to 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.