Abstract

This review article focuses on lead (Pb), one of the most ubiquitous and harmful toxicants found in soil. Our objective is to address misconceptions regarding the ability of plants to uptake Pb through their roots and translocate it to above-ground tissues, and their ability to act as hyperaccumulators and thereby phytoextract Pb. In accordance with a number of cited definitions, we suggest that species capable of Pb phytoextraction can be rated with the following three criteria: (1) root uptake above a nominal threshold of 1,000 mg Pb/kg, (2) bioconcentration factor (BCF or shoot/soil concentration) >1, and (3) translocation factor (TF or shoot/root concentration) > 1. We review the literature in the updated USDA Phytoremediation Database and conclude that without amendments: no plant has met all three criteria; no plant has been confirmed as a Pb hyperaccumulator. Our analysis suggests that Pb phytoextraction is not a viable remediation option. Pb phytostabilization, however, may be an effective remediation tool in a variety of settings. Planting some of the many species capable of tolerating soil Pb exposure and sequestering it in or around the root zone will limit Pb movement into other ecosystems, prevent resuspended dusts, and mitigate Pb exposure.

摘要

这篇评论文章重点介绍铅（Pb），铅是土壤中最普遍和有害的毒物之一。我们的目标是解决有关植物通过其根部吸收Pb并将其转运到地上组织的能力以及其充当超富集剂并由此植物提取Pb的能力的误解。根据许多引用的定义，我们建议可以使用以下三个标准对具有铅植物提取能力的物种进行评级：（1）根摄入量超过标称阈值1,000 mg Pb / kg，（2）生物富集系数（BCF或芽/土壤浓度）> 1，以及（3）易位因子（TF或芽/根浓度）> 1。没有植物被确认为铅超积累物。我们的分析表明，铅植物提取不是一种可行的补救措施。但是，Pb植物的稳定作用可能是在各种情况下的有效补救工具。种植能够忍受土壤铅暴露的许多物种中的某些物种并将其隔离在根部区域内或周围，将限制铅向其他生态系统的迁移，防止粉尘再悬浮并减轻铅的暴露。