Influence of particle size and total organic carbon on the distribution of polybrominated diphenyl ethers in landfill soils: assessment of exposure implications
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Date
2019-05-30
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Journal of Analytical Science and Technology
Abstract
Background: The selection of soil fraction is an important influencing factor to accurately determine human
exposure risk to toxic chemicals in the environment. The present study evaluated the concentrations of prevalent
polybrominated diphenyl ethers (PBDEs) in different size fractions of soil from a landfill site and the factors that
influence their distribution in the soils.
Method: Samples were fractionated into size fractions; between 150–250 and 45–150 μm (after initial sieving
through a 250 μm sieve) and, thereafter, PBDEs were extracted using a mixture of toluene-dichloromethane and
subsequently cleaned with a multilayer silica gel/Pesticarb/sodium sulphate column and analysed using GC-MS.
Results: The sum of seven PBDE congeners (BDE-28, -47, -100, -99, -154, -153 and -183) ranged from 7.08 to
10.8 ng g−1 with a total median of 7.32 ng g−1, and from 7.00 to 8.77 ng g−1 with a total median of 7.21 ng g−1,
corresponding to size fractions 150–250 μm and 45–150 μm, respectively. BDE-183 was predominant in both soil
fractions. A significant correlation was observed between Σ7PBDEs concentrations and total organic carbon (TOC),
particularly for particle size 150–250 μm (r2 = 0.829, p < 0.05).
Conclusion: The study revealed that PBDE concentrations did not automatically increase with decreasing particle
size, and as such, PBDE-treated consumer goods and consequent abrasions of flame retardant-containing materials
could be likely sources. The study also clarified that selecting soil fractions arbitrarily for exposure risk assessment
may lead to inconclusive results. The study results, therefore, have important inferences for estimating flame retardant
chemical exposure.
Description
Research Article
Keywords
PBDEs, Human exposure, TOC, Particle size, Soil, South Africa