Long-term comparison of the performance of biostimulation and phytoextraction in soil contaminated with diesel and heavy metals

The long-term remediation performance under the natural conditions is required to establish the appropriate remediation strategy for contaminated soil. The objective of this study was to compare the long-term remediation efficiency of biostimulation and phytoextraction in contaminated soil containing petroleum hydrocarbons (PHs) and heavy metals. Two types of contaminated soil (soil contaminated with diesel only and co-contaminated with diesel and heavy metals) were prepared. For the biostimulation treatments, the soil was amended with compost, whereas maize, a representative phytoremediation plant, was cultivated for the phytoextraction treatments. There was no significant difference in remediation performance of biostimulation and phytoextraction in the diesel-contaminated soil, in which the maximum total petroleum hydrocarbon (TPH) removability was 94–96% (p 1. Correlation analysis revealed that soil properties (pH, water content, and organic content) negatively correlated with pollutants removal. Additionally, the soil bacterial communities were changed over the investigated period, and the types of pollutants exerted a significant influence on the bacterial community dynamics. This study performed a pilot-scale comparison of two types of biological remediation technologies under natural environmental conditions and provided information on changes in the bacterial community structures. This study can be useful for establishing appropriate biological remediation methods to restore soil contaminated with PHs and heavy metals. [Display omitted] •Effects of biostimulation and phytoextraction in contaminated soil were compared.•Phytoextraction was superior in diesel and heavy metals co-contaminated soil.•Maize was a suitable plant for phytoextraction with a TF of >1.•Soil properties negatively affected the phytoextraction performance.•The