铅、镉在蔬菜中的累积特性及对蔬菜生长的影响

Accumulation characteristics of lead and cadmium in vegetables and their effects on the growth of vegetables

采用不同浓度原位污染土盆栽试验,研究铅(Pb)、镉(Cd)在8种蔬菜中的累积规律及对蔬菜生长的影响,揭示蔬菜-土壤铅、镉含量相关关系,提出8种蔬菜的土壤铅、镉安全临界值。结果表明:油菜、甘蓝长势均好,生长未受抑制,其他几种蔬菜随铅、镉浓度的增加,生长受到不同程度抑制;铅、镉复合污染对8种蔬菜的生长抑制程度为芹菜>莴苣>胡萝卜>豇豆>辣椒>番茄>甘蓝、油菜,与蔬菜累积铅、镉能力一致;芹菜-土壤铅、镉含量呈显著线性相关(R2=0.923,0.956);土壤铅安全临界值为叶菜类(甘蓝、油菜)>根茎类(莴苣、胡萝卜)>豆类(豇豆)>芹菜和辣椒,番茄土壤铅安全临界值待定;8种蔬菜土壤镉安全临界值相同。

A pot experiment was conducted with a soil originally contaminated with different con- eentrations of lead and cadmium, to determine the accumulation characteristics of lead and cad- mium in 8 kinds of vegetable species and their effects on the growth of vegetables. The purposes of this study were to discover the relationship of lead and cadmium concentrations in vegetables and soil and to find the safety thresholds of lead and cadmium concentrations in soil for the eight vegetables. The results indicated that the cabbage and baby bokehoi grew well and their growth weren＇ t inhibited, while the growth of other species was inhibited to varying degrees with the in- crease of lead and cadmium concentration. The degree of growth inhibition of vegetables was in the descending order of celery, lettuce, daueus carrot, cowpea, pepper, tomato, cabbage and baby bokchoi, which was in accordance with their capacity of lead and cadmium accumulation. There were significant linear correlations between lead, cadmium concentrations of celery and soil （R2=0.923, 0.956）. The critical values of lead in soil for different vegetables were in order of： leaf vegetables （cabbage, baby bokchoi） 〉 root vegetables （lettuce, carrot） 〉 beans （eowpea） 〉 celery and pepper. The critical value of lead in soil wasn＇ t fixed for tomato. The critical values of cadmium in soil were the same for the 8 vegetables.