Chemical forms of cadmium in soil and its distribution in French marigold sub-cells in response to chelator GLDA

The use of degradable chelating agents to facilitate phytoextraction is a promising low-cost method for the remediation of heavy metal-contaminated soils. However, there are few studies on how plants and soils respond to the chelating agents. In this study, the responses of French marigold ( Tagetes patula L.) and soil cadmium (Cd) to the chelator tetrasodium glutamate (GLDA) was investigated in a 180 d field trial. Five GLDA treatments (0, 292.5, 585, 1170, and 2340 kg hm −2 ) were carried out in a Cd-contaminated soil (0.47 mg kg −1 ) under French marigold plantation. The results showed that the application of GLDA promoted the transformation of other forms of Cd in soil to exchangeable state, and the exchangeable Cd and Fe–Mn oxide bound state increased by 42.13% and 32.97% ( p