酸雨和降尘污染对菠菜和生菜几种重金属含量的影响

Effects of Dust Droping and Acid Rain Pollution on Contents of Heavy Metals in Spinach and Lettuce

在温室条件下模拟酸雨和降尘,通过盆栽试验对菠菜和生菜进行不同的受试处理。结果表明,单一酸雨作用使菠菜及生菜Cu,Pb,Cd,Cr元素含量均随pH的降低而呈现上升趋势,而且表现出良好的负相关性;单一降尘作用使菠菜及生菜Cu,Pb,Cd,Cr元素含量均高于空白。酸雨和降尘复合作用时,2种蔬菜对同一种重金属表现出不同的变化规律:随酸雨pH的逐渐降低,菠菜Cu元素含量一般先上升然后呈现下降趋势,而生菜4种重金属元素含量均呈现上升趋势。复合作用时,同一种蔬菜对不同重金属亦有不同的pH敏感点:菠菜对Cu,Cr元素敏感点为pH=5;对Pb,Cd敏感点为pH=4。与我国食品卫生标准相比,单一酸雨和降尘作用及复合作用均使菠菜Cd元素含量全部超标,超标倍数最大,为2.5倍,其次为Cr,再次为Pb。对于酸雨的敏感性,菠菜比生菜敏感。

By simulating acid rain and dust-fall under the condition of green-house, spinach and lettuce were given different trial treatments in pot planting experiments. The results showed that the contents of Cu, Pb, Cd, Cr in spinach and in lettuce increased with the pH value decreasing through single acid effect, and the contents had a significant negative relationship with the pH value. The contents of Cu, Pb, Cd, Cr in spinach and in lettuce were higher than the control test through single dust-fall effect. And two vegetables showed different trends with the same heavy mental through the compound effect. For example, the contents of Cu in spinach increased in earlier stage and decreased in later as the pH value decreasing , but the contents of Cu, Pb, Cd, Cr increased in lettuce. For different heavy mental, the same vegetable had different pH acute points through the compound effect , such as spinach , the acute point of both Pb and Cd was pH = 4, while the acute point of both Cu and Cr was pH = 5. Compared to the food hygiene standard of PRC, both single and compound effect made the contents of Cd far beyond the level, even the most multiple of exceeding standard was 2.5, then followed by Cr and Pb the last Spinach was acuter than lettuce for the sensitivity of acid rain.