Soil Immobilization of Heavy Metal Using Soil Amendments in a Greenhouse Study

ABSTRACT

The application of soil amendments to immobilize heavy metals is a promising technology to meet the requirements for environmentally sound and cost-effective remediation. The present work was carried out to evaluate the effect of phosphogypsum (PG) used alone and in combination with compost (CP) at a mix ratio of 1:1 wet weight ratio (PG+CP) at 10 and 20 g dry weight kg⁻¹ dry soil, on heavy metal immobilization in contaminated soil, and on canola growth (Brassica napus). The results were then compared with untreated soil (control). The results revealed that the Pb, Cd, and Zn uptake of canola plants was reduced by the application of PG alone and when it was mixed with CP. At an application rate of 10 g dry weight kg⁻¹ dry soil of (PG+CP), the dry weight of canola plants increased by 66.8%, which was increased in comparison on its weight in the untreated soil (control). The addition of PG alone resulted in more pronounced immobilization of heavy metals as compared to PG mixed with CP. Plant growth was improved with CP addition but heavy metals immobilization was greatest in PG alone treatments. Results suggest that PG may be useful for the immobilization of heavy metals in contaminated soils.