硅酸盐对污染土壤铬、铅形态和小白菜吸收分布及其健康风险的影响

为保障蔬菜的品质安全,通过土壤盆裁试验,研究硅酸盐对Cr、Pb单一污染及Cr-Pb复合污染土壤中小白菜(Brassica chinensis)的生物量、土壤中Cr、Pb形态及小白菜体内Cr、Pb积累量的影响.结果表明,在受到较高水平的Cr～Pb污染时,小白菜对Pb的富集能力要明显高于Cr,被小白菜吸收的Cr、Pb都主要累积在根部.施用硅酸盐能通过减少土壤中有效态Cr、Pb的含量,从而减少小白菜对Cr、Pb的吸收,且施用效果明显,其中2.0 g/kg效果最好,但该处理严重抑制小白菜生长,不适于生产应用.而Si_1处理(1.00 g/kg)能在不影响产量的前提下极显著地降低小白菜茎中Cr、Pb的质量分数,并使叶中Pb的质量分数降至国家标准限量值附近或低于限量值,因此该处理在生产上极具应用前景.

Effect of Silicates on Cr,Pb Forms in Soil,Distribution in Brassica chinensis and Health Risk of Brassica chinensis under the Stress of Cr-Pb Pollution

The situation of soil heavy metal pollution was threatenning the quality and safety of vegetable produetion in Guangdong.Aiming at ensuring the safety of vegetable,pot experiments were carried out to study the effects of silicate on growth and Cr,Pb forms in soil and Cr,Pb uptake of Brassica chinensis which were growing up in Cr-Pb contaminated soil.The results indicated that,Brassica chinensis accumulated more Pbthan Cr when polluted by high density of Cr-Pb.Cr and Pb were mostly cumulated in root.Silicate can reduce the uptake of Cr,Pb by decreasing the available forms of them.The 2.0 g/kg silicate has the best effect,but Brassica chinensis can't grow normally when treated by such dose.While 1.0 g/kg silicate can reduce the uptake by stem significantly without decreasing yield.Pb in leaf can be reduced to about the standard limited value or below when treated by 1.0 g/kg silicate.This level of silicate(1.0 g/kg) is more suitable than high level(2.0 g/kg)to apply to production.