Abstract A novel approach to soil remediation has been developed in which soil washing and the addition of organic by-products are carried out simultaneously in a single step. This method was tested on soil contaminated with Cd, Pb and Zn. The soil was washed in batches (35 kg soil/batch) with ethylenediaminetetraacetate (Na-, Ca-EDTA), sulfuric acid, and the reducing agent Na-dithionite, while organic by-products such as chicken manure, spent mushroom substrate, and corn cobs (2–5%) were mixed homogeneously into the soil. Results showed that this approach not only removed significant amounts of contaminants (58% Cd, 61% Pb and 12% Zn), but also improved soil properties, including increasing the amount of plant-available water, reducing leaching of residual toxic metals, reducing uptake of toxic metals in Brassica juncea and increasing β-glucosidase and dehydrogenase activity. The addition of organic by-products also prevented the accumulation of Na in the process after a series of batches and enabled the recycling (ReSoil® method) and continuous reuse of EDTA and the process solutions. However, the treatment also had a negative impact on plant growth, reducing the growth of Brassica juncea by 44%. Overall, this innovative approach is promising for effective and sustainable soil remediation, but further research is needed to optimize the process and minimize its impact on plant growth.
Gluhar et al. (Thu,) studied this question.