Impact of Different Types of Activated Carbon on the Bioaccessibility of 14C-phenanthrene in Sterile and Non-Sterile Soils

Ayodeji Oyelami,Babajide Elegbede,Kirk Semple

doi:10.3390/environments1020137

Abstract

In this study, the impact of three different types of activated carbon (AC) on the bioaccessibility of 14C-phenanthrene in non-sterile and sterile soils was investigated. A single dose (1%) of each of the different AC (CB4, CP1 and AQ5000) was blended with soil spiked with 50 mg·kg−1 of 12C/14C-phenanthrene. The mineralisation of the 14C-phenanthrene was monitored over a 14 day incubation period by indigenous soil microflora and an enriched inoculum of Pseudomonas sp., while uptake in earthworms, Eisenia fetida, was measured after incubation for 10 days at 1, 25, 50 and 100 d. Bioaccessibility was assessed using hydroxypropyl-β-cyclodextrin (HPCD) solution. Results showed that the presence of AC had a significant effect upon the extents of mineralisation, earthworm uptake and HPCD extraction, when compared to the control. Aquasorb CB4 was the least effective amongst the different AC used. The characteristics of the different AC used was also seen to have a major influence on how each AC would have an effect on its use in soil remediation in reducing bioaccessibility, mobility and risk.

Highlights

Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic contaminants (HOCs) widely found in the environment from many natural and anthropogenic sources [1,2]
The impact of CB4, AQ5000 and CP1 on the mineralisation of 14C-phenanthrene was measured in non-sterile and sterile soils, respectively
This study has demonstrated that the use of activated carbon (AC) reduces bioavailability and bioaccessibility of

Summary

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic contaminants (HOCs) widely found in the environment from many natural and anthropogenic sources [1,2]. Due to their carcinogenic and mutagenic characteristics, as well as their persistence, there is significant interest in their fate and behaviour in soils and sediments [3]. Black carbon (BC) is a collective term for the natural forms of carbonaceous sorbents, such as soot and charcoal [4] They are widely present in soil and may account for about 1%–15% of total organic carbon [5,6]. BC is believed to enhance sorption of PAHs in soils and sediments [7,8]; leading to reductions in desorption [9], causing reductions in extractability and bioaccessibility of PAHs to biota, including microorganisms [10]

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