Influence of particle size and total organic carbon on the distribution of polybrominated diphenyl ethers in landfill soils: assessment of exposure implications

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 ∑ 7 PBDEs concentrations and total organic carbon (TOC), particularly for particle size 150-250 μm (r 2 = 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.

Waste streams as current sources of persistent organic pollutants and organophosphate esters in Africa - a critical review

“…Relatively high concentrations for ∑ 18 PCBs (1000-4900 ng/g) were reported by Debela et al from soil samples collected from an old transformer dumpsite in Addis Ababa, Ethiopia [39] . The dominant congener was again reported as PCB-52 (mean = 360 ng/g).…”

“…On intercontinental comparison, the range of 50-120 pg/m 3 5] [39,70] . The mean concentration of the individual BDEs 28, 47, 100, 99, 154, 153, 183 and 209 observed in Ghana's WEEE soil [23] [Supplementary Table 4] exceed the reports on Ireland, and particularly BDE-209 is 16 times greater than (mean = 1600 ng/g) the concentration reported for Ireland (upper limit = 100 ng/g).…”

Formal waste treatment facilities as a source of halogenated flame retardants and organophosphate esters to the environment: A critical review with particular focus on outdoor air and soil

“…in Shanghai, China (Jiang et al, 2010(Jiang et al, , 2012Wu et al, 2015), indicating considerable PBDE emissions during the landfill disposal process. Comparably elevated PBDE concentrations in soils from landfills were reported in northern Canada, South Africa, and Brazil (Akortia et al, 2019;Cristale et al, 2019;Danon-Schaffer et al, 2008). For example, in northern Canada, the average concentration of ∑60PBDEs was 131 ng•g -1 dw in surface soils impacted by waste dumpsites and landfills, while in background areas an average PBDE concentration of 1.94 ng•g -1 dw was identified (Danon-Schaffer et al, 2008).…”