土壤环境中重金属生物有效性评价方法及其环境学意义

重金属生物有效性是衡量重金属元素迁移性和生态影响的关键参数,在生态地球化学评价中有重要的作用。国土资源部目前进行的新一轮多目标区域生态地球化学调查与评价,使重金属生物有效性受到进一步的重视。本文评述国际上基于化学和基于生物学两种对生物有效性概念理解及其分歧,评价各种生物有效性评价方法发生的背景、应用范围和优缺点。物理化学法和土壤生物学评价法是两类主要的生物有效性评价方法,经常使用的包括化学总量预测法、化学一步提取法、顺序提取法、自由离子活度法(唐南膜平衡法)、植物指示法、微生物学评价法等。各种方法间往往相互独立,尚未形成被一致接受的方法,从而影响了生物有效性在风险评价和污染治理等工作中的应用。未来发展的重点是,进一步加强重金属生物有效性的理论研究,实现土壤学、化学和生物学的融合,将评价方法统一化和标准化,提高数据的可靠性和对比性,同时将越来越多地应用于我国多目标生态地球化学调查与评价,提高调查质量和服务水平。

Methods and Environmental Implications of Measuring Bioavailability of Heavy Metals in Soil Environment

Heavy metal bioavailability,as a key index for estimating heavy metal mobility and effect on the ecoenvironment,is significant in ecogeochemical estimate.It was attached more attention in the new round of multi-purpose regional geochemical survey and ecological appraisal that being undertaken by the Ministry of Land and Resources.This paper comments on the comprehension and difference between two definitions to the concept of bioavailability,which are based on chemistry and biology respectively,estimates the generating background,application regions and advantages and disadvantages of various bioavailability measuring methods.Physical chemical and soil biological methods are two primary bioavailability measuring methods.The usual methods include chemic gross prediction,single extraction,sequential extraction,free ion activity,plant indicator and microbiology estimate etc.All methods are independent to one another,and no one has been accepted conformably.This confused situation influenced the practical application of the bioavailability in risk assessment and pollution treatment etc.Author put forward the research preference in the future is strengthening the theoretical research on heavy metal bioavailability,implement the combination of soil science,chemistry and biology,unify and standardize the estimate methods,improve the reliability and comparability.At the mean time,it should be applied more and more in multi-purpose regional geochemical survey and ecological appraisal to improve the investigation quality and service level.