富硒土壤的主要驱动因素和农作物风险评价—以陕南岚皋县高硒土壤分布区为例
Main driving factors of rich-selenium soil and crop risk assessment: A case study of high-selenium soil distribution area in Langao County, Southern Shaanxi Province
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摘要: 摘要: 土壤中硒的分布不均匀,其分布规律和成因一直不清。为了研究陕西安康富硒核心区的岚皋县高硒土壤的空间分布规律及成因,本文在全县采集了767个表层土壤,其中在典型高硒区(佐龙镇和民主镇)按行政村的地块(山区的耕地大部分很小,不超过1亩)为单位,共加密采集了409个土样、18个土豆、35个玉米和14个基岩,分别利用HG-AFS和ICP-MS测试了其总硒、总砷含量和其他微量元素含量。结果表明:岚皋县北部典型高硒地区佐龙镇和民主镇土壤硒含量均值分别为3.38 mg/kg(0.02-37.39 mg/kg)和3.11 mg/kg(0.05-16.96 mg/kg),均远高于中国和世界表层土壤硒含量的背景值。佐龙镇和民主镇表层土壤硒含量大于0.4mg/kg的面积分别占各自乡镇面积的99.18%和75.79%。高硒区的土豆(0.04~1.78 mg/kg,均值0.49mg/kg)和玉米(0.01~2.82 mg/kg,均值0.69mg/kg)的富硒率均超过68%,但是存在潜在的健康风险。高硒区土壤富硒的最主要原因是晚前寒武纪-寒武纪的富硒地层大面积出露,导致风化形成的上覆土壤的硒含量相应较高,因此这两个乡镇是名副其实的富硒区。Abstract: Abstract: The distribution of selenium in soil is uneven, and its distribution and origin is not clear. In order to study the spatial distribution and causes of high-selenium soil in Langao County, the Se-rich core area of Ankang, Shaanxi Province, 767 surface soils samples were collected from the whole county. In the typical high-selenium areas (Zuolong Town and Minzhu Town), the plots of administrative villages (most of the cultivated land in the mountainous area is very small, no more than 1 mu) were taken as units. A total of 409 soils, 18 potatoes, 35 corns and 14 bedrocks were collected by encryption. The contents of total selenium, total arsenic and other trace elements were measured by HG-AFS and ICP-MS, respectively. The results showed that the average soil selenium content of Zuolong and Minzhu Towns in northern Langao County was 3.38 mg/kg (0.02-37.39 mg/kg) and 3.11 mg/kg (0.05~16.96 mg/kg), respectively, which were far higher than the background values of soil selenium content in China and the world. The selenium content above 0.4mg/kg in the surface soil of Zuolong Town and Minzhu Town accounted for 99.18% and 75.79% of the respective township area, respectively. The selenium enrichment rates of potatoes (0.04~1.78 mg/kg, mean 0.49mg/kg) and corns (0.01~2.82 mg/kg, mean 0.69mg/kg) in the high selenium zone were both over 68%, but there were potential health risks. The main reason for the enrichment of selenium in the soil in the high selenium area is that the selenium-enriched strata in the Late Precambrian-Cambrian was exposed in a large area, resulting in a correspondingly higher selenium content in the overlying soil formed by weathering. Therefore, these two towns are veritable selenium-rich areas.
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Key words:
- Langao County /
- Surface soil /
- Selenium content /
- Health risk /
- Zuolong Town /
- Minzhu Town
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