绿化带中紫花苜蓿嫩芽含铅量的分析

Determination of the amount of lead in the seedling of alfalfa planted in different greenbelt in Yinchuan

为了研究食用紫花苜蓿嫩芽铅污染,首次采用电感耦合等离子体-原子发射光谱法(ICPA-ES),连续三年测定了银川市西夏区干道绿化带旁及建筑垃圾垫土种植的绿化带中紫花苜蓿嫩芽的含铅量变化.测试结果显示:干道旁绿化带中种植的紫花苜蓿嫩芽铅质量含量在三年内最大增长幅度为4.3mgk/g(n=5),RSD<1.0%,污染最严重的样品中铅质量含量超过国家对蔬菜中铅质量含量规定的最高限量值26倍,表明铅污染呈逐年加重趋势;建筑垃圾垫土上种植的绿化带中生产的紫花苜蓿嫩芽中铅质量含量在第一年严重超标,但在两年后平均下降了2.36mgk/g(n=5),RSD<1.0%,是国家对蔬菜中铅质量含量规定的最高限量值的11倍;数据显示在没有持续外源污染的情况下,已受到铅污染的紫花苜蓿内在的污染程度在逐年减轻.试验表明,食用干道两侧紫花苜蓿嫩芽对人体有危害.

The amount of lead in the seedling of alfalfa gathered from different places in Yinchuan was determined by ICP-AES. The national standard for the highest amount of lead in vegetable is 0. 2 mg/kg and in feeds is 5 mg/kg. The results showed：the amount of lead in the seedling of alfalfa which was gathered along the main road the first year ranged from 1.2 - 2.8 mg/kg,exceeds 6 - 14 times of the national standard for vegetable; the amount of lead in the seedling of alfalfa which was gathered from the greenbelt whose earth came from the rubbish of architecture is 4. 86 mg/kg, exceeds 24. 3 times of the national standard for vegetable, both of the amount of lead are higher than the national standard for feeds. Two years later, the amount of lead in the alfalfa from the greenbelt alongside the main road went up drastically while the latter one went down obviously. So, alfalfa from the greenbelt alongside the main road is poisoned by lead and not suitable for feeds.