三种不同类型土壤上水稻对Cu、Pb和Cd单一及复合污染的响应

Response of Rice in Three Types of Soils to Cu , Pb and Cd with Single and Combined Pollution

水稻对重金属有较强的吸收能力,本文采用温室盆栽试验研究了Cu、Pb和Cd在中国土壤环境质量标准Ⅲ级水平(Pb:400mgkg-1;Cd:1.0mgkg-1;Cu:100mgkg-1)时于3种不同类型土壤上对水稻生长和吸收Cu、Pb及Cd的影响。结果表明,在红壤上,Cu处理显著降低了稻谷产量,Pb和Cd本身对稻谷产量影响不大,但Pb显著增加了Cu的毒性;Cu或Cd的共存对Pb在稻米中含量的影响较小,但其含量也均超过国家食品卫生标准(0.4mgkg-1);在Cu-Cd、Pb-Cd和Cu-Pb-Cd处理中,稻米Cd含量较Cd单独存在时分别增加了135%、84%和126%。在红壤性水稻土上,仅有Pb和Cu-Pb-Cd处理与对照相比降低了稻谷产量;Cu-Pb-Cd处理稻米中Pb或Cd含量较Pb或Cd单独存在时分别增加了141%和360%;Pb或Cu分别与Cd共存时,对稻米Cd含量影响不显著。在乌栅土上,各处理对稻谷产量影响均不大,且多数表现为增加。Cu、Pb和Cd对水稻的毒性是红壤>红壤性水稻土>乌栅土。稻米中Cu、Pb和Cd含量与土壤NH4OAc提取态Cu、Pb和Cd含量之间均达到极显著线性相关。

Pot experiments were carried out to study the effects of Cu, Pb and Cd with single and combined forms in three different types of soils on yield and heavy metals accumulation of rice （Oryza sativa L.）. The results showed that, in the red soil, compared with the treatment of Pb 400 mg.kg^-1 soil or Cd 1 mg＇kg^-1 soil, Cu of 100 mg.kg^-1 soil was more toxic to the rice growth. The rice yield decreased significantly, while the coexistence of Pb aggravated the toxicity of Cu, the coexistence of Cu-Cd, Pb-Cd and Cu-Pb-Cd significantly increased the rice Cd concentration by 135%, 84% and 126% respectively, compared to the CK. The interaction effect of coexistent metals on rice Pb concentration was not significant; however, the rice Pb in all the Pb treatments exceeded the Food Hygiene Standards in China （0.4 mg.kg^-1）. In the paddy soil, the combined effects of Cu with Pb and Cd on the yield of rice in other two paddy soils were less significant than those in the red soil, the rice Pb and Cd concentrations in the Cu-Pb-Cd treatment increased by 141% and 360% compared with the Pb or Cd treatment alone. In Wushan soil, the existence of Cu or Pb and Cd did not significantly increase the rice Cd concentration. The toxicity of Cu, Pb and Cd to rice in three type soils was red soils〉paddy soil〉Wushan soil. The concentrations of Cu, Pb and Cd in the soils extracted by 1.0 mol· L^-1 NH4OAc showed good correlation with their concentrations in the rice.