The Uptake And Accumulation Of DEHP By The Plant Of Benincasa Hispida

With the progress of society, more and more attention has been paid to food safety issues. Phthalate (2-ethylhexyl) phthalate (DEHP) as a plasticizer has been widely used in the production of PVC plastic products. Because phthalate plasticizers are not chemically bound to PVC, DEHP can leach, migrate and evaporate into the atmosphere, indoor air, soil, water and food, it can be through direct or indirect ways for human health hazard. The mechanism study on the absorption and accumulation of DEHP by the plants is important to evaluating the ecological risk and the protection of human health and the development of phytoremediation technology. In this study, the characteristics of uptake and accumulation of DEHP by B. hispida from the macroscopic plant organs to microscopic cell tissues were investigated. The factors influenced on the uptake and accumulation of DEHP, and the effectiveness of B. hispida plants on phytoremediation were determined. In addition, a two- compartment model was suggested to describe the accumulation of DEHP in the B. hispida plants. The main conclusions are shown as follows:(1) The B. hispida plant roots, stems, leaves, fruit peel and flesh could absorb and accumulate DEHP from the atmosphere. After six weeks growing, the B.hispida plants can accumulate more than 700 milligrams of DEHP, and most of DEHP accumulate in B. hispida fruit. In the equilibrium state, the B. hispida plant roots, stems, leaves, fruit peel and pulp accumulated DEHP content were quite different. The DEHP accumulated content from root to tip decreased. DEHP accumulated in the petiole was the highest compared to those in root, stem and leaves in the same part, and the DEHP content in the stem section was 11 times of that in the adjacent root, and the ratio of DEHP content between the stem and leaf in the same part decreased with the increase of the tender.(2) The DEHP cumulated in the peel of B. hispida was positively correlated to those in the fruit. That meant that DEHP in fruit meat mainly came from the peel. DEHP transportation from peel to fruit meat of the young fruit was slower than that of the old fruit. The DEHP content in the fruit meat was about 1/3-1/5 of the peel in the same part. The change of DEHP content in the fruit meat section was lower than that of the peel section.(3) The inner parts of root, stem and leaves of B. hispida accumulated different amount of DEHP. DEHP mainly distributed in the waxy wall, chloroplasts and mitochondria of the tissues. DEPH content in Cell waxy wall> DEPH content in chloroplast and mitochondria> DEPH content in ribose. High DEHP content in lipoprotein or glycolipids suggested they may be the carrier of DEHP in the cells.(4) Environment temperature influenced the DEHP uptake of B.hispida plants. Low temperature was beneficial for the adsorption of DEHP of the plant while high temperature could improve the transportation of DEHP in plant. The DEHP content accumulated in the plant were positively correlated to the environmental DEHP concentration. DEHP in leaves increased with the increase of the ambient humidity in the first stage, then decreased in the last stage. DEHP in the fruit meat increased with the increase of the ambient humidity.(5) B. hispida plants can actively absorb the DEHP in environment according our in greenhouse experiments. Benincasa hispida plants were able to remove 65% -76% of DEHP in the environment with high DEHP level, and 85% -92% DEHP in the environment with low DEHP level, which indicated B. hispida plants can be used for the repair of air polluted by DEHP.(6) B. hispida plants could lowered 8/9 to 9/10 of DEHP content in cabbage and rapeseed cabbage which were intercropped with B. hispida plants, which indicated that the plants can be used for the DEHP pollution of some vegetables which are planted in area polluted by DEHP.(7) B. hispida leaves possess strong ability of DEHP adsorption. The adsorption met the Freundlich model, and adsorption kinetics met the Lagergren equation. Based these characteristics, two-compartment model was suggested to describe the DEHP adsorption of B. hispida from air.