海涂湿地生态系统中重金属元素的富集特征

Accumulation characteristic of heavy mental elements in wetland ecosystem

利用样线法和样方法布点,用收获法采集海涂湿地生态系统中植物互花米草Spartina alterniflora各部位和土壤样品,用X-荧光和原子吸收分光光度法分别测定土壤和植物体不同部位中Pb、Cd、Cu、Zn的含量,探讨了4种重金属元素在浙江沿海湿地生态系统中的富集特征.结果表明:(1)在土壤库中,元素含量高低和储量大小均为Zn>Cu>Pb>Cd;在植物库中,重金属在植物不同部位的含量高低为根系>茎叶,储量大小为茎叶>根系;在植物根系和茎叶中,元素含量和储量大小均为Zn>Pb>Cu>Cd.(2)植物不同部位对重金属的富集能力不同,表现为根系>茎叶.植物根系对不同重金属的富集能力大小为Zn>Cd>Pb>Cu;茎叶对不同重金属的富集能力大小为Cd>Zn>Pb>Cu.对4种重金属在植物体内和土壤中的含量分别进行相关性分析,发现植物体内Pb、Cu的含量与土壤中的呈极显著正相关,而Cd、Zn在两者间的相关性不显著.(3)受环境因素的影响,在不同取样地,土壤库中4种重金属的总储量有差异,表现为宋埠样地(161.867 kg/hm2)>胜利塘样地(156.626 kg/hm2)>杨屿山样地(129.004 kg/hm2);但在植物库中,重金属的总储量大小却为杨屿山(26.266 kg/hm2)>胜利塘(21.69 kg/hm2)>宋埠(10.923 kg/hm2).显示了由于不同样地互花米草群落的生物量以及其对重金属吸收能力的差异,表现出该群落中重金属储量与土壤库中重金属储量的明显不一致.

In order to study the transportation characteristic and accumulation of heavy mentals in wetland, Pb, Cd , Cu, Zn content in Spartina alterniflora community were calculated. Based on sampling belt method, using X-fluorescence analysis technique and atomic absorption spectrum method Pb, Cd, Cu, Zn content in Spartina alterniflora community were separately calculated. The results showed： （ 1） heavy mental storage was Zn 〉 Cu 〉 Pb 〉 Cd in soil pool ; in different positions of Spartina alterniflora, heavy mental elements content was root 〉 stem and leaf while total storage was opposite, it was stem and leaf 〉 root; in plant pool, elements content and storage in root were Zn 〉 Pb 〉 Cu 〉 Cd, and in stem and leaf was the same as in root.（ 2 ）Accumulation of heavy mental elements of Spartina alterniflora was different according to positions, the rule was root 〉 stem and leaf. To different mentals, accumulation ability was Zn 〉 Cd 〉 Pb 〉 Cu in root, but in stem and leaf was Cd 〉 Zn 〉 Pb 〉 Cu. Corrrelation analysis on four elements content in plant and soil showed that ： Pb and Cu contents in plant were significancntly positive to contents in soil, but Zn and Cu were not in level of significance. （3） Heavy mentals storage in soil was different in different plots, it showed： SB（ 161. 867 kg/hm^2 ） 〉 SLT （ 156. 626 kg/hm^2 ） 〉 YYS （ 129. 004 kg/hm^2） ; but in plant pool, it was YYS { 26. 266 kg/hm^2） 〉SLT（21.69 kg/hm^2） 〉 SB（ 10.923 kg/hm^2 ）. It showed that because of differences in Spartina alterniflora community biomass and absorption abilities of different heavy mental elements, heavy mental storage in communities was not consistent with that in soil pool.