摘要
选取迄今世界上唯一发生过人群硒中毒爆发性流行的地区──湖北恩施市双河乡渔塘坝为研究区。研究表明，在表生中—强风化环境中，硒是一个相当活泼的元素。在渔塘坝0．01km2的微地域内，土壤硒、玉米硒的分布存在着显著的不均一性。微地形、淋失条件是影响二者硒含量及其分布的主要因素。土壤硒含量基本决定了玉米硒含量。渔塘坝中硒在玉米中的基本分布规律是雄花、雌蕊＞叶＞籽＞根＞茎，上部叶片＞下部叶片、上部茎节＞下部茎节、果穗外表皮硒＞果穗内表皮硒。上述规律不仅间接证明硒有可能是植物生长中的必需元素，而且还表明，高硒背景、无蓄硒指示植物条件下，植物中相对累积硒的器官可以作为环境硒水平的敏感指标。
Yutangba, where a sudden incidence of selenium poisoning occurred in 1963, is located in the northern part of Shuanghe Township about 81 km east of Enshi City in the southwest of Hubei Province, China. The average concentrations of selenium in Yutangba are (4.06 ± 1. 24) mg/kg for soil, (4. 36 ± 3. 27) mg/kg for corn root, (3.06 ± 2. 24) mg/kg for corn stem, (9. 79 ± 7. 62) mg/kg for corn leaf and (8. 07 ± 5. 02) mg/kg for corn seed.The study shows that selenium is an active element in the supergene moderate - strong chemically weathering environment in a small area of 0. 01 km2 in Yutangba. The spatial distribution of selenium in soil and corn is significantly uneven. Relatively low-Se, median-Se and high-Se subregions can be distingUished according to soil and corn Se concentrations. Microtopographic features and leaching conditions are the primary factors not only goveming the selenium concentration in soil and com, but also affecting its distribution. Selenium concentration in soil basically controls that in corn.Selenium concentrations differ significantly among the organs of corn and decrease in the following order: tassel(male flower), silk (female flower) > leaf > seed > root > stalk > leafy husk of the ear. The selenium concentrations in the upper leaves and stalks are greater than those in their lower cognates, and the outer leafy husk of the ear has a greater selenium concentration than the inner leafy husk. This distribution not only indicates that selenium is probably an essential element for corn, but also that, under high-Se background and no Se-accumulating indicator plant conditions, these plant organs with relatively high selenium concentrations may be used as a sensitiveindicator of selenium levels in the environment.
出处
《地球化学》
CAS
CSCD
北大核心
2000年第1期43-49,共7页
Geochimica
基金
国家自然科学基金!49373186
关键词
土壤硒
玉米硒
硒分布
景观地球化学
硒
selenium in soil
selenium in corn
selenium distribution
Yutangba mini-landscape
Hubei Province
