含铅、镉重金属细颗粒物对几种陆生植物的暴露危害

大气重金属细颗粒物复合污染对陆生植物早期发育及幼苗生长的影响研究近年来成为大气科学与生态毒理学交叉领域研究的热点和难点。通过搭建合理的暴露场景,模拟严重大气污染浓度条件下,含Pb、Cd细颗粒物对黄瓜、小麦、西红柿和玉米4种受试植物出苗、幼苗生长期内茎高和鲜重等生物量的影响。结果显示,暴露处理组4种受试植物陆上部分对Cd元素的吸收增量变化范围为0~0.025 mg·kg-1;对Pb元素的吸收增量变化范围为0.020~0.292 mg·kg-1。暴露处理组4种受试植物出苗抑制率变化范围为0%~30%;茎高抑制率变化范围为-3%~14%;鲜重抑制率变化范围为-12%~3%。由此可见,在试验周期内,含Pb、Cd重金属细颗粒物复合污染对几种植物的陆上部分生物量的抑制作用不明显,甚至有积极的刺激作用。与空白对照组相比,暴露处理仅对小麦出苗抑制产生显著性差异,并显现协同效应。说明几种受试植物在现有暴露环境下,对设定浓度的污染物敏感性较低,受危害程度不大。

Hazard Assessment of Several Terrestrial Plants Exposed to Fine Particulate Matters Containing Heavy Metals Lead and Cadmium

The combined pollution of atmospheric heavy metal-containing particles has negative impacts on the seedling growth and early stage growth of terrestrial plants. In this paper, we established exposure scenarios to simulate the ambient atmosphere with severe heavy metal pollutions. Under these scenarios, hazardous impacts of fine particles containing Pb and Cd towards the emergence, seedling growth, stem length and fresh weight of cucumber, wheat, tomato and corn were evaluated. The results of all four plants in treatment group are as follows: for the aboveground parts, the Pb absorption incremental ranged from 0 to 0.025 mg·kg-1, the Cd absorption incremental range from 0.020 to 0.292 mg·kg-1; the inhibition rate of plant emergence ranged from 0 to 30%; the stem length ranged from -3% to 14%; the fresh weight range from -12% to 3%. Thus, during the test period, inhibitory effect of combined heavy metal pollution was not significant to the plant biomass. On the contrary, a positive stimulus was observed. Compared with the control groups, significant difference was observed on wheat emergence inhibition in treatment groups and a synergistic effect was observed. It can be concluded that, under the exposure levels in current experiment, no significant damages were caused by the heavy metal pollutants. Th