Effect of single and mixed polycyclic aromatic hydrocarbon contamination on plant biomass yield and PAH dissipation during phytoremediation

Seniyat Larai Afegbua,Lesley Claire Batty

doi:10.1007/s11356-018-1987-1

Seniyat Larai Afegbua, Lesley Claire Batty

Open Access

https://doi.org/10.1007/s11356-018-1987-1

Copy DOI

Abstract

Polycyclic aromatic hydrocarbon (PAH)-contaminated sites have a mixture of PAH of varying concentration which may affect PAH dissipation differently to contamination with a single PAH. In this study, pot experiments investigated the impact of PAH contamination on Medicago sativa, Lolium perenne, and Festuca arundinacea biomass and PAH dissipation from soils spiked with phenanthrene (Phe), fluoranthene (Flu), and benzo[a]pyrene (B[a]P) in single and mixed treatments. Stimulatory or inhibitory effects of PAH contamination on plant biomass yields were not different for the single and mixed PAH treatments. Results showed significant effect of PAH treatments on plant growth with an increased root biomass yield for F. arundinacea in the Phe (175%) and Flu (86%) treatments and a root biomass decrease in the mixed treatment (4%). The mean residual PAHs in the planted treatments and unplanted control for the single treatments were not significantly different. B[a]P dissipation was enhanced for single and mixed treatments (71–72%) with F. arundinacea compared to the unplanted control (24–50%). On the other hand, B[a]P dissipation was inhibited with L. perenne (6%) in the single treatment and M. sativa (11%) and L. perenne (29%) in the mixed treatment. Abiotic processes had greater contribution to PAH dissipation compared to rhizodegradation in both treatments. In most cases, a stimulatory effect of PAH contamination on plant biomass yield without an enhancement of PAH dissipation was observed. Plant species among other factors affect the relative contribution of PAH dissipation mechanisms during phytoremediation. These factors determine the effectiveness and suitability of phytoremediation as a remedial strategy for PAH-contaminated sites. Further studies on impact of PAH contamination, plant selection, and rhizosphere activities on soil microbial community structure and remediation outcome are required.

Highlights

There has been a marked increase in research on phytoremediation as a promising eco-friendly reme-Responsible editor: Elena Maestri diation technology
Root biomass yield decrease was observed for L. perenne with 5, 6, and 8% for Phe, Flu, and mixed Polycyclic aromatic hydrocarbon (PAH) treatments respectively compared to the control
The effect of the single and mixed PAH treatments on the root and shoot biomass of M. sativa and L. perenne compared to the control plants was not significant (p > 0.05)

Summary

Introduction

This has been driven by reports of enhanced biodegradation of organic compounds including PAH in the presence of plants compared to unplanted soils (Siciliano et al 2003; Xu et al 2006; Olson et al 2007; Vangronsveld et al 2009; Wu et al 2011). There are conflicting reports on the phytoremediation outcome (enhancement or inhibition) as a few studies have shown that presence of plants may not necessarily enhance PAH dissipation (Sun et al 2010; Smith et al 2011). Many phytoremediation studies have shifted towards mixed contamination remediation to reflect real site remediation scenarios as early studies were mainly on single contaminant remediation (Gan et al 2009)

Objectives

Methods

Results

Discussion

Conclusion