| Title: | "Modeling plant uptake of organic contaminants by root vegetables: The role of diffusion, xylem, and phloem uptake routes" |
| Address: | "School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong 518107, China. Electronic address: lizijian3@mail.sysu.edu.cn" |
| DOI: | 10.1016/j.jhazmat.2022.128911 |
| ISSN/ISBN: | 1873-3336 (Electronic) 0304-3894 (Linking) |
| Abstract: | "The uptake of organic contaminants by root vegetables involves diffusion, transport by xylem and phloem saps, degradation, and volatilization. To understand the role of uptake and elimination routes in the bioconcentration modeling of organic contaminants, a two-compartment uptake model (root and leaf compartments) was proposed. The results showed that for the root compartment, logarithm values of bioconcentration factors (log BCF, the concentration ratio between plant tissues and soil) of chemicals fell within a narrow range when the logarithm of octanol-water partition coefficient (log K(OW)) was less than 3.0, whereas log BCF values decreased rapidly with increasing log K(OW) values when log K(OW) was greater than 3.0. This is because the diffusion route had a significant impact on the root uptake of chemicals, wherein the first-order rate constant dropped rapidly for high-lipophilicity chemicals, resulting in very low log BCF values. For the leaf compartment, chemicals with moderate lipophilicity (log K(OW) of 3.0-4.0) had the highest simulated log BCF values. This is because moderate log K(OW) values generated the highest transpiration stream concentration factors (TSCFs, the concentration ratio between xylem or phloem saps and water), resulting in high uptake efficiency of chemicals by leaves. Furthermore, we improved the uptake model by considering the surface-deposition route for pesticides (foliar spray), and the simulation results indicated that this uptake route cannot be neglected for lipophilic compounds. Although the simulations agreed with an experimental study and some reported data, future studies should focus on factors, such as plant physiology (plant varieties, periderm effects and compositions of xylem and phloem saps) and environmental conditions (soil properties and weather conditions), to improve the plant uptake model" |
| Keywords: | *Phloem Plants Soil *Vegetables Water Xylem Bioconcentration factor Crop safety Environmental modeling Organic compounds Plant protection products Soil pollution; |
| Notes: | "MedlineLi, Zijian eng Netherlands 2022/04/24 J Hazard Mater. 2022 Jul 15; 434:128911. doi: 10.1016/j.jhazmat.2022.128911. Epub 2022 Apr 13" |
