会泽铅锌矿渣堆周边7种野生植物重金属含量及累积特征研究

Heavy Metal Contents and Accumulation Characteristic of Seven Wild Plants from the Slagheap Surrounding of Huize Lead-zinc Tailings

调查了云南会泽铅锌矿冶炼矿渣堆周边野外植物,采样分析了土壤和植物重金属含量,研究了植物重金属累积特征。研究结果表明:该矿渣堆周边土壤污染以Cd最为严重,平均含量为101mg·kg-1,是云南土壤背景值的462倍;其次是Zn(9065mg·kg-1)和Pb(3244mg·kg-1),分别是云南土壤背景值的101倍和80倍。采集到的7种植物中,土荆芥(Chenopodium ambrosioidesL.)、芨芨草(A chnatherum splendens Trin.Nevski)和莎草(Cyperus microiria steud)体内Cd含量较一般植物高出105～112倍。土荆芥的Cd转运系数为2.5,具有较高的Cd转运能力;芨芨草和莎草的Cd富集系数均大于1,具有较强的Cd富集能力。这3种植物对Cd的吸收特性值得进一步研究。芨芨草和莎草体内Pb含量分别为2045、1623mg·kg-1,达到Pb富集植物临界含量标准。野葵(MalvaverticillataL.)的Zn转运系数高达4.1,具有很强的Zn转运能力。狗牙根(Cynodon dactylon L.Pers.)的Pb、Zn、Cd转运系数均大于1。这5种植物对重金属具有很强的富集能力,可作为Pb、Zn和Cd污染土壤植物修复的富集植物,对铅锌矿废弃地及尾矿区重金属污染土壤的修复治理具有重要的意义。

A field survey on wild plants growing in the slagheap surrounding of Huize lead-zinc tailings was carried out. The samples of plants and soils were collected. The contents of Cd, Pb and Zn in plants and soil were measured. The heavy metal accumulation characteristics of seven wild plants were studied. The results showed that the soil from the slagheap surrounding of lead-zinc mining tailings was contaminated by cadmium. The average content of Cd was 101 mg·kg^-1 , which was 462 times of the background level of soil in Yunnan Province. The average contents of Zn and Pb were 9065 mg·kg^-1 and 3244 mg·kg^-1 , which were 101 times and 80 times of the background levels of soil in Yunnan Province. It was found that the seven wild plants had different abilities of uptake and accumulation of Pb, Zn, Cd. The contents of Cd in Chenopodium ambrosioides L., Achnatherum splendens Trin. Nevski and Cyperus microiria Steud were more than 100 mg·kg^-1 , which were 105～112 times higher than that in normal plants（1 mg·kg^-1 ）. The transfer coefficient of Cd in C. ambrosioides was 2.5, indicating high transportation capacity of Cd. The bioconcentration coefficient of Cd in A.splendens and C. microiria were higher than 1, indicating high bioconcentration capacity of Cd. It suggests that the Cd absorption characteristics of these three plants need further researches. The contents of Pb in A.splendens and C. microiria were 2045 mg·kg^-1 and 1623 mg·kg^-1 , which exceeded the threshold value（1000 mg· kg-1 ）as a Pb hyperaccumulator. The Zn transfer coefficient of Malva verticillata L. was up to 4.1, showing a strong transfer ability to Zn. The transfer coefficient of Cynodon dactylon L. Pers. to Pb, Zn and Cd were more than 1. In general, the results indicate that the five wild plants had strong bioconcentration capacity to heavy metal and could be useful as hyperaccumulator for phytoremediation of soil polluted by Pb, Zn and Cd.