海南五指山树仔菜重金属镉的生态地球化学研究

Study on Eco-Geochemistry of Cadmium in Sauropus androgynus from Wuzhishan City of Hainan Province

对海南省五指山市南圣镇什贺村(属全海南岛表层土壤背景下的镉非异常区)的树仔菜和红山镇什蛇田村(镉异常区)的包心菜、生菜、芥菜、茼蒿菜的根系土、植物样进行了配套采集分析。结果表明,所采集的树仔菜样品镉含量个别超标,镉的土壤环境质量大都符合国家规定的标准;但是研究区土壤中镉的有效量占比远高于其他元素,镉较其他元素更倾向于在树仔菜中富集,而且树仔菜较其他品种蔬菜更强烈地选择性吸收富集镉,更兼镉在树仔菜中的富集部位恰恰就是可食部分茎和叶,因此,树仔菜的食用安全性不容忽视。另外,土壤中的镉测试结果表明,对树仔菜的种植地要进行大比例尺的土壤详查评价工作,以精确圈定安全的种植地域,确保树仔菜的食用安全性。

Based on the research achievements from eco-geochemical investigation, the samples of soils and vegeta- bles from Zhahe Village （the area of cadmium-normal in surface soils） and Zhashetian Village （the area of cadmium- abnormal in surface soils）, Wuzhishan City, Hainan Province are collected and analyzed. The analytical results show that cadmium-abnormal only occurs in few sauropus androgynu samples and Cd contents in most soil samples accords with the national criterion. But the proportion of available Cd to total Cd in soils is higher than other elements and cadmium is more inclined to be absorbed and enriched by Sauropus androgynus. Furthermore, cadmium is more easily enriched in the Sauropus androgynus stem and leaf which are the edible parts of Sauropus androgynus. The results also show the further detailed investigation to soils is necessary to ensure the safety of eating Sauropus androgynus.