Yang Qing-Wei, Lan Chong-Yu, Shu Wen-Sheng
Department of Resource and Environmental Sciences, Chongqing Jiaotong University, Chongqing, 400074, People's Republic of China.
Environ Monit Assess. 2008 Dec;147(1-3):65-73. doi: 10.1007/s10661-007-0098-0. Epub 2007 Dec 12.
As well known, at normal levels, copper and zinc are essential micronutrients for plants, animals, and humans. However, excessive Cu and Zn are toxic and disturb a wide range of biochemical and physiological processes. Using Atomic Absorption Spectrophotometer (AAS; Perkin-Elmer 3030, USA), soil and rice plant (Oryza sativa L.) samples collected from a paddy field in Lechang lead-zinc mine area, Guangdong Province, China were analyzed and their potential ecological impacts to local human and livestock were evaluated. The results showed that the paddy soils were contaminated with Cu and Zn. Both metals in soils had low bio-available fractions for paddy plants, animal and human by three chemically analytical techniques. Generally, were concentrations of copper and zinc root >> straw > stalk > grain with hull > grain without hull (i.e. unpolished rice) and in the normal ranges indicating no ecological risk for local livestock and residents. All positive correlation coefficients, however, between heavy metals in rice plant and total, exchangeable (step 1 in Tessier's method established in 1979) and DTPA-extractable fractions in soils were found in this study indicating that elevated heavy metal in soils would increase long-term exposition and possible consequence of ecological hazard through food chains.
众所周知，在正常水平下，铜和锌是植物、动物和人类必需的微量营养素。然而，过量的铜和锌具有毒性，会干扰广泛的生化和生理过程。使用原子吸收分光光度计（美国珀金埃尔默3030型），对从中国广东省乐昌铅锌矿区稻田采集的土壤和水稻植株（水稻）样本进行了分析，并评估了它们对当地人和牲畜的潜在生态影响。结果表明，稻田土壤受到铜和锌的污染。通过三种化学分析技术，土壤中的这两种金属对水稻植株、动物和人类的生物可利用部分含量较低。一般来说，铜和锌在根部的浓度 >> 稻草 > 茎杆 > 带壳谷粒 > 糙米，且处于正常范围内，表明对当地牲畜和居民没有生态风险。然而，本研究发现，水稻植株中的重金属与土壤中的总量、可交换态（1979年建立的 Tessier 方法中的步骤1）和 DTPA 可提取部分之间均呈正相关，这表明土壤中重金属含量升高会增加长期暴露风险，并可能通过食物链产生生态危害后果。
