Geochemical characteristics and influential factors of soil selenium in typical agricultural area, Chongqing
YU Fei1(), ZHANG Feng-Lei1, ZHANG Yong-Wen1,2, WANG Rui1,3, WANG Jia-Bin1
1. Southeast Sichuan Geological Group,Chongqing Bureau of Geology and Minerals Exploration,Chongqing Key Laboratory of land quality geological survey,Chongqing 400038,China 2. College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China 3. School of Earth Sciences,China University of Geosciences,Beijing 100083,China
以重庆市典型农业区——南川区为研究区,系统采集了表层土壤样品,测定了Se元素含量,分析讨论了土壤Se地球化学特征及其影响因素。研究结果表明,南川区土壤Se含量变化范围为(0.056~10.80)×10-6,平均值为0.46 ×10 -6,高于全国土壤硒的平均值,其中富硒土壤面积占42.31%。南川区土壤Se含量在空间上呈现出“南高北低”的特点,土壤高Se区主要集中分布在南部的水江镇、南平镇、南川城区及金佛山地区,南川区城镇地区和工矿区土壤Se含量最高,农田用地土壤Se含量最低。南川区高 Se 土壤主要分布在二叠系、三叠系(飞仙关组合嘉陵江组)、志留系、奥陶系和寒武系地层,土壤Se含量主要受成土母质控制,与土壤有机质呈显著的正相关关系,总体上呈现出随海拔的增加而增加的趋势,但与土壤pH关系不显著。
Nanchuan District is a typical agricultural area in Chongqing. The authors investigated the geochemical characteristics and influential factors of soil Se from Nanchuan District of Chongqing City to provide some scientific bases for the survey of environment background and regional production as well as human health. More than 8 496 soil samples from the topsoil layers(0~20 cm)all over the Nanchuan District were collected and analyzed for content and distribution of soil Se and their relationships with parent material, soil properties (pH and Corg), altitude and human factors. The research results show that the content of total selenium ranges from 0.056×10-6 to 10.80×10-6 with a mean value of 0.46×10-6, which indicates that the most of the soils are in the category of Se-sufficiency to Se-abundance, with 42.31% being Se-enrichment. The spatial characteristics of soil Se content in Nanchuan District show "high in the south and low in the north", and the soil Se enrichment areas are mainly distributed in Shuijiang Town, Nanping Town, Nanchuan urban area and Jinfo Mountain. Among the types of soils existing in the Nanchuan District, Se content is the highest in industrial and mining land soil and the lowest in farmland. The spatial characteristics of soil Se content and strata show a similar variation pattern. The soil Se enrichment is mainly distributed in Permian, Triassic (Feixianguan Formation and Jialingjiang Formation), Silurian, Ordovician and Cambrian strata, which indicates that the soil Se content is mainly controlled by parent materials in Nanchuan District. In addition, Se content in soil is significantly positively correlated with soil organic matter and altitudes, but significantly negatively correlated with soil pH.
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