根际环境重金属地球化学行为及其生物有效性研究进展

根际是土壤或滨岸沉积物中受植物根系及其生长活动影响的微域环境 ,具有特殊的物理、化学和生物性质 ,影响了重金属在根际环境中的分布、累积和生物有效性。从重金属在根际环境的分布与累积、地球化学赋存形态、生物有效性以及影响重金属根际行为和生物有效性的主要因素(温度、Eh和溶解氧、p H、根系分泌物、微生物 )、重金属根际吸收、富集、排斥和固定过程的调控、重金属耐性植物的筛选和培养 6个方面概述了近 1 0年来国内外在根际环境重金属地球化学行为及其生物有效性方面的主要研究进展 ,并指出了其存在问题以及今后的努力方向。

RESEARCH PROGRESS IN GEOCHEMICAL ACTIVITIES AND BIOAVAILABILITY OF HEAVY METALS IN RHIZOSPHERE ENVIRONMENT

Rhizosphere is the micro region environment influenced by plant roots and its activities in soil or coastal sediments. Due to its special physical, chemical and biological characteristics, the distribution, accumulation and bioavailability of heavy metals in rhizosphere soil or sediments differ from the non rhizosphere. On one hand, heavy metals in plants can be accumulated through the food chain step by step, which would threat the health of mankind and bring great loess to the society economy; on the other hand, the adsorption of heavy metals in plants can cut down the heavy metal concentration of heavy metal contaminated soils or sediments and reduce its environmental endangers. In this paper, some main progresses in geochemical activities and bioavailability of heavy metals in rhizosphere environment during the latest ten years at home and abroad are reviewed, including the distribution and accumulation of heavy metals in rhizosphere, the geochemical forms, bioavailability of heavy metals in rhizosphere, main factors influencing the activities and bioavailability of heavy metals in rhizosphere ( including tempreture, Eh and dissolved oxygen, pH, root exudates and microbe), the adjusting and control of heavy metal adsorption, accumulation, exclusion and fixation processes in rhizosphere, the screening and cultivating of heavy metal tolerant plant. The existing problems and striving direction are also pointed out.