Partitioning of polycyclic aromatic hydrocarbons between plant roots and water

Abstract

Partition of phenanthrene between water and roots was determined for 13 plant species using a batch equilibration technique. Partition coefficients (K rt ) from 734 to 2,564 L/kg were measured. A simple model to estimate the partition of organic contaminants between roots and water was developed based on the composition of plant roots and the 1-octanol/water partitioning coefficient. The estimates were close to the observed results, with differences of < 14%. The partition coefficients of phenanthrene by root cell walls were 13-84% greater than sorption by the corresponding roots. The cell wall fraction-the dominant fraction of root organic components-was identified as the primary domain for partition of phenanthrene. The measured hydroponic uptake of phenanthrene into roots was always less than phenanthrene partition by plant roots. A modified sorption model containing a quasi-equilibrium factor (α pt ) could reasonably predict hydroponic uptake by plant roots. The results obtained from this study provide insights into partition of highly lipophilic organic chemicals in roots, and provide convenient methods to estimate this partition as well as uptake of such chemicals in rootwater systems.

Transport via xylem and accumulation of aflatoxin in seeds of groundnut plant

“…The presence of aflatoxin in the xylem sap confirmed the absorption of aflatoxin by roots and translocation to aerial parts via the xylem. According to Li et al (2005), Gao et al (2008) highly lipophilic contaminants, characterized by high n-octanol-water partitioning coefficients (Kow, >3 log unit) or low water solubilities (Sw), have a high tendency to be absorbed by plant roots from water. The log p of AFB 1 is 1.73, and its solubility in water is 0.23 g À1 L (Wishart et al, 2013).…”

Lipid content disturbance in the arbuscular mycorrhizal, Glomus irregulare grown in monoxenic conditions under PAHs pollution

“…High concentrations of PAHs have been found in soils all over the world (Sung et al 2002;Gao et al 2006Gao et al , 2008. PAHs pollution of soils represents, therefore, risks of the human food chain contamination by crops and vegetables (Collins et al 2006).…”

Producción, postproducción y agrotecnias de semillas, hortalizas y frutas. Coadyuvantes en la seguridad alimentaria en México y Cuba

“…Se ha demostrado que los compuestos orgánicos entran a la planta a través de transporte pasivo, el cual está relacionado con la hidrofobicidad del contaminante. De manera general, las raíces de las plantas tienden a absorber más los contaminantes del agua del suelo mientras más hidrofílico es el compuesto y, mientras mayor sea el contenido lipídico de la planta, mayor es la captación del contaminante orgánico hidrofóbico (Gao et al, 2008). Por ejemplo, se ha visto que los plaguicidas, especialmente los organoclorados como DDT, son especialmente solubles en los aceites y ceras de las plantas (Ripley y Edgington, 1983).…”