Mass balance evaluation of polybrominated diphenyl ethers in landfill leachate and potential for transfer from e-waste (original) (raw)
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Modeling of PBDEs in Landfills and Other Systems
A mass-balance model is being developed to predict the environmental fate of polybrominated diphenyl ethers (PBDEs) in landfills and other systems where they occur. The model considers changes over time for different congeners and includes inputs (e.g. due to e-wastes and polyurethane foam), transfers between the wastes and soil, water and air, reactions that may alter the relative composition of different congeners, and accumulation over time. Specification of various terms in the model will require experimental measurements, now in progress. The model will produce a set of differential equations to be integrated simultaneously by conventional methods. The model may be extended later, with appropriate inputs, to apply to larger systems such as regions 1 .
Environmental Monitoring and Assessment, 2013
An assessment of the concentrations of selected polybrominated diphenyl ether (PBDE) congeners as well as BB 153 in leachate samples collected from three landfill sites within the city of Cape Town was conducted. A liquid-liquid extraction technique was employed for the isolation of all the target compounds from the leachate samples. Extracts obtained were further subjected to multi-layer column chromatography employing different forms of silica gel. The prepared samples were analysed using a high capillary gas chromatograph equipped with a micro-electron capture detector (GC-μECD). The overall mean concentrations of the total PBDEs, including BDE 209 ranged between 5.65 and 2,240, 0.28-20.5 and 1.66-1,170 ng/l for Bellville, Coastal Park, and Vissershok landfill sites, respectively. The mean concentrations of BB 153, which were generally low in most of the samples analysed, were 70.4, 7.14 and 8.16 ng/l for Bellville, Coastal Park and Vissershok sites, respectively. The influence of precipitation on the characteristics and quantity of leachate produced from the landfill sites investigated was most pronounced during the August/September sampling regime. Generally, the trend observed in this study clearly indicated a wide variation in the levels of these contaminants in all the landfill sites studied from one sampling period to the other. However, the principal component analysis revealed that the release of these contaminants might be associated with two or three possible sources. This study further confirmed the relevance of landfill leachate as an important source of PBDE contamination of the environment, especially the groundwater and surface water sources.
Journal of Analytical Science and Technology, 2019
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.
Polybrominated diphenyl ethers (PBDEs) in leachates from selected landfill sites in South Africa
Waste Management, 2009
The last few decades have seen dramatic growth in the scale of production and the use of polybrominated diphenyl ethers (PBDEs) as flame retardants. Consequently, PBDEs such as BDE-28,-47,-66,-71,-75,-77,-85,-99,-100,-119,-138,-153,-154, and-183 have been detected in various environmental matrices. Generally, in South Africa, once the products containing these chemicals have outlived their usefulness, they are discarded into landfill sites. Consequently, the levels of PBDEs in leachates from landfill sites may give an indication of the general exposure and use of these compounds. The present study was aimed at determining the occurrence and concentrations of most common PBDEs in leachates from selected landfill sites. The extraction capacities of the solvents were also tested. Spiked landfill leachate samples were used for the recovery tests. Separation and determination of the PBDE congeners were carried out with a gas chromatograph equipped with Ni 63 electron capture detector. The mean percentage recoveries ranged from 63% to 108% (n = 3) for landfill leachate samples with petroleum ether giving the highest percentage extraction. The mean concentrations of PBDEs obtained ranged from ND to 2670 pg l À1 , ND to 6638 pg l À1 , ND to 7230 pg l À1 , 41 to 4009 pg l À1 , 90 to 9793 pg l À1 for the Garankuwa, Hatherly, Kwaggarsrand, Soshanguve and Temba landfill sites, respectively. Also BDE-28,-47,-71 and BDE-77 were detected in the leachate samples from all the landfill sites; and all the congeners were detected in two of the oldest landfill sites. The peak concentrations were recorded for BDE-47 at three sites and BDE-71 and BDE-75 at two sites. The highest concentration, 9793 ± 1.5 pg l À1 , was obtained for the Temba landfill site with the highest BOD value. This may suggest some influence of organics on the level of PBDEs. Considering the leaching characteristics of brominated flame retardants, there is a high possibility that with time these compounds may infiltrate into the groundwater around the sites since most of the sites are not adequately lined.
Investigation of PBDEs in Landfill Leachates from Across Canada
Environmental Management and Sustainable Development, 2014
Leachates from 27 landfills (e.g. planned disposal area) across southern Canada and 11 dump sites (e.g. unorganized disposal area) in the Canadian North were collected (2006) and analysed (2006-2008) for polybrominated diphenyl ethers (PBDEs). There was wide variability in the results, both in terms of the total PBDE concentrations and in the distribution of congeners. Northern sites tended to have lower concentrations than southern ones, but some northern levels were significant, despite the low population density and lack of industry in the north. The North could potentially act as a sink for PBDE contaminants because many organic compounds get deposited via air or water currents in the North even though they were not manufactured there.
Sewage treatment plants (STPs) are an important source to the environment for many chemicals of concern (COCs). Polybrominated diphenyl ethers (PBDEs) are one such group of COCs of present day concern for which studies on fate and transport during the STP process are limited. Availability of robust and well-tested STP models is useful in the quantification of environmental loadings and associated risk from STP discharges. In the present study, one such model (STP model) has been tested on monitoring data collected at a full-scale STP for five congeners of a commercial PBDE technical mixture. Results show that the observed trend of chemical removal and concentrations at various stages of the sewage treatment process were well simulated by the STP model for all five PBDE congeners. Continued development and evaluation of the model should continue in the future to improve its reliability and expand its applicability to a larger universe of COCs.
Environmental Science and Pollution Research, 2014
Polybrominated diphenyl ethers (PBDEs) are known to be persistent, endocrine disruptors and bioaccumulative and can cause adverse health effects in animals and humans. In this study, river and landfill sediment samples were collected from selected rivers and municipal solid waste landfill (MSWL) sites across Gauteng Province in South Africa to determine the levels of common PBDEs (BDE-17, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183 and BDE-209). The mean and median concentrations of Σ 8 PBDEs from river sediment samples was 2.4 and 0.4 ng g −1 , respectively, and a range of 0.8-114 ng g −1. The highest concentration of Σ 8 PBDEs (43.6 ng g −1) was observed at Jukskei River with more than two orders of magnitude greater than the rest. The observed total PBDE concentrations in landfill sediment and leachate samples ranged from 0.8 to 8.4 ng g −1 and 127-3,702 pg L −1 for the two matrices. BDE-209 was predominantly detected in most of the sediment samples. Two of the MSWLs which are lined with geomembranes gave the highest concentrations of ∑ 7 PBDEs (2,678 and 3,702 pg L −1). Correlation values for ∑ 7 PBDEs versus Co (r=0.65), Cu (r=0.52), Mn (r=0.10), Mg (r=0.76), Ca (r=0.66) and Ni (r=0.77) with a statistical significance (p<0.05) were observed except for Na, Cr, Pb, K, Fe and Zn (p>0.05). The observed positive correlation may suggest a possible influence of trace metals on PBDE concentrations in leachates. Furthermore, a test of relationship between major anions and PBDEs yielded positive relationship with Cl − (r=0.94, p=0.16), F − (r=0.97, p=0.21), Br − (r=0.6, p=0.29) and NO 3 2− (r=0.96, p=0.08) with an insignificant statistical difference. However, evaluation of the relationship between some water quality parameters (pH, dissolved oxygen and electrical conductivity) gave negative correlation with PBDE concentrations.
Environmental Monitoring and Assessment
The occurrence of selected brominated flame retardants, including nine PBDE congeners, HBCDD and TBBPA in leachate samples from 8 landfill sites in South Africa were investigated. In addition, the possible influences of dissolved organic carbon on their levels were also evaluated. Filtered leachate samples were subjected to solid-phase extraction to isolate the various target compounds. PBDEs with six bromine substituents and above, as well as α-HBCDD, β-HBCDD and TBBPA were generally found below the detection limit. However, the mean value of the total lower PBDE congeners ranged between 0.04 and 0.48 µg L-1 and the concentrations of γ-HBCDD ranged from not detectable (ND) to 0.05 µg L-1. No significant correlation was observed between the target compounds and DOC, although weak to moderate correlations were mostly observed for the lower PBDEs.
Atmospheric Environment, 2004
In the first of two papers, the atmospheric poly brominated diphenyl ether (PBDE) concentrations at a municipal solid waste incineration (MSW) plant with electronic recycling is compared with that at an industrial urban reference site producing asphalt and concrete. In the second paper, atmospheric deposition and washout behaviour is presented (Atmos. Environ. (2004a)). PBDEs (BDE28, À47, À66, À100, À154, À153, À183, À209) in the gaseous and particulate phase were measured with high resolution in time during the colder parts of the year to minimise the influence of potential historical pollution at the sites through volatilisation. This also means that reported levels are lower compared to other reported data. Results of BDE47 (TetraBDE) and BDE209 (DecaBDE) as representatives of ''old'' vs. ''new'' PBDEs as well as P PBDE, excluding BDE209, are presented. Median P PBDE, BDE47 and BDE209 concentration were 6.3, 2.1 and 10.4 pg m À3 at the MSW and 3.5, 1.7 and 6.5 pg m À3 at the reference site. The total concentrations (gaseous and particulate phase) were significantly higher at the MSW compared to the reference site for P PBDE and BDE47 but not for BDE209. The same results were obtained regarding concentrations in the gaseous phase. Particle concentrations were significantly higher at the MSW for P PBDE, BDE47 and BDE209. Within each site, the gaseousphase concentration was significantly higher than the particulate-phase concentration except for BDE209 at the MSW. Thus, the proportion of BDE209 detected in the particulate phase was higher at the MSW compared to the reference site. Together with the results of the second paper, we suggest that treatment of waste is presently a source of ''old'' PBDEs to the environment, whereas the rather similar BDE209 concentrations at the two sites are more a result of proximity to potential diffuse sources. r