Identification of weed species with hyperaccumulative characteristics of heavy metals

In order to promote the effective and economic remediation of soils contaminated with single Cd and Cd combined with Pb,Cu and Zn,a field-screening study on weed hyperaccumulators was carried out on the basis of field pot-culture experiments used to determine characteristics of weed plants enduring and accumulating heavy metals. In this study,54 weed species belonging to 20 families from agricultural fields of the Shengyang suburbs were tested. The results showed that Taraxacum mongolicum,Solanum nigrum and Conyza canadensis could strongly tolerate single Cd and Cd-Pb-Cu-Zn combined pollution,had high Cd-accumulative ability,and generally possessed basic characteristics of hyperaccumulators. Because there are synergic and antagonistic effects among Cd,Pb,Cu and Zn,single-factor pollution tests should be done as well as combined pollution tests during the identification of hyperaccumulators to ensure the efficiency of phytoremediation and the practical significance of hyperaccumulators identified. The field pot-culture experiment should be a new tentative method to screen out accumulative and tolerant species in view of its obvious advantages such as simple operation,low cost,and easy identification of investigated plants.