Evaluation of chemical enhancement on phytoremediation effect of Cd-contaminated soils with Calendula officinalis L.

The popular ornamental plant Calendula officinalis L was studied for its potential application in the phytoremediation of cadmium (Cd)-contaminated soils. Enhancements to the Cd accumulation by the application of sodium dodecyl sulfate (SDS), ethylenediaminetriacetic acid (EDTA) and ethylenegluatarotriacetic acid (EGTA) to the soil were investigated. Under these chemically enhanced treatments, EDTA was observed to be toxic to the plants leading to retarded growth. However, the application of SDS and/or EGTA was shown to result in significantly increased plant biomass (p < 0.05). Most of the chemical treatments resulted in increases to the shoot and root Cd concentrations, with the root Cd concentration being consistently higher than that shoot Cd concentration. Almost all of the investigated chemical treatments containing SDS or and EGTA were shown to lead to an increase in the total Cd content in the plants (p < 0.05). The application of EGTA alone led to an observed total Cd increase of up to 217%. This investigation revealed considerable efficiency of chemical enhancement and correspondingly increased potential of Calendula officinalis L. for applications of phytoremediation of Cd-contaminated sites.