微量元素在湖积物、土壤的垂向分布与稻谷中的分配

VERTICAL DISTRIBUTION IN LAKE SEDIMENTS AND SOILS AND PARTITION WITHIN PADDY FOR RELEVANT TRACE ELEMENTS:PRELIMINARY TESTING RESULTS FROM ECO-GEOCHEMICAL SURVEY IN JIANGSU

报道了“江苏省国土生态地球化学调查”项目有关湖积物、土壤柱微量元素垂向分布及稻谷样元素分配研究的初步成果。通过对有关样品元素含量的分析对比,指出洪泽湖沉积柱元素垂向分布与其动荡的沉积环境关系密切、太湖局部沉积物在其目前20cm以上深度存在人为重金属污染,这二湖沉积物中其氮与总有机碳含量呈显著正相关;认为城市化可使当地土壤环境受重金属等污染的深度显著加大、城市土壤环境受人为活动的影响要显著高于农村;发现Mo易富集于稻米、重金属与营养元素易富集于稻皮、各元素在米-谷间的分配关系不确定。

The preliminary testing results obtained through ecological geochemical survey and assessment of Jiangsu Province include vertical distribution of relevant trace elements in part lake sediments, vertical variability of some element contents with depth within typical soil samples, and trace element partition between rice and husks in the paddy. By analyzing and contrasting elements' contents and its change within relevant studied samples, basic conclusions have been obtained as the following: (1) vertical distribution of relevant trace elements of bottom sediments is mainly controlled by changing depositing environment in Hongzehu Lake, and there is a obvious relative enrichment trend of heavy metals at about 20cm deep ranges in upper sediments in Taihu Lake, so it is thought that there is obvious artificial pollution of heavy metals in its present upper 0～20cm depth sediments from some local areas of Taihu Lake, and there is a distinct positive correlation between nitrogen and total organic carbon in sediments from Taihu and Hongzehu Lake; (2)vertical characteristics of heavy metal elements within typical soil columns shows urbanization resulted in more complicated variation of element contents at different soil depths and made soil depth polluted by heavy metals become deeper sharply in some urban and its suburb, and the human activity has more influences on environmental change of soil on urban than on rural ones; (3)experimental data from some testing samples of paddy point out that molybdenum is liable to enrichment in race, and other heavy metal and health-giving trace elements, for example for Zn, Co, Ni, Cd, Pb, As, Se, Ca, Cu, Fe, Mg, Mn, and so on, are liable to enriched in husk of paddy at most,there is not a very obvious and constant partition relationship between rice and paddy for every elements in total 14 testing samples. Above stated studying experiences and its information can provide a part of helpful clues and suggestions for present developing agro-geological survey in our nation.