Phytoremediation of petroleum hydrocarbon-contaminated soils with two plant species: Jatropha curcas and Vetiveria zizanioides at Ghana Manganese Company Ltd

Abstract

The study investigated the effects of Jatropha curcas (JC) and Vetiveria zizanioides (VZ) on hydrocarbon concentration levels in mine spoils. A 2 × 2 × 3 factorial arrangement of treatments in a completely randomized design with 3 replications was adopted. With compost amendments, JC caused 78.8 and 82.2% and VZ caused 51.1 and 39.7% decline in soil TPH and TOG concentrations, respectively after 16 weeks. Compost amendments significantly reduced TOG and TPH concentrations compared to the other treatments in both JC and VZ (p < 0.0001). However, the effect of species on TOG and TPH concentrations were marginally significant (p = 0.081 and p < 0.006, respectively). Growth in height, collar diameter and number of leaves in JC were significantly higher in the compost amendment compared to the fertilizer and control treatments (p < 0.0001). Number of leaves (p = 0.009) and collar diameter growth (p = 0.010) were significantly lower in contaminated soils compared to non-contaminated soils. Furthermore, only the number of tillers in Vetiver was significantly influenced by the soil amendments (p = 0.003) and the soil hydrocarbon levels (p = 0.048). It is concluded that phytoremediation particularly with JC is an alternate means to reducing soil hydrocarbon concentration levels. However, soils must be amended with compost for effective remediation and rapid, vigorous, early growth of plants.

Keywords:

• Amendments
• collar diameter
• compost
• contamination
• oil and grease
• soil

Acknowledgments

The support of the management of the Ghana Manganese Company Limited in providing the premises for conducting this study and funding for the data analysis is greatly appreciated. The author is also grateful to Mr. Philip Amponsah, Mr. Lawrence Kobby Antwi, and their colleagues as well as the numerous individuals who assisted with field data collection and the laboratory analysis of the soil samples. The contributions of the two anonymous reviewers are greatly appreciated.