| 1. |
- Bateni, Fatemeh, et al.
(författare)
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Distribution, source and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments of northern part of the Persian Gulf
- 2022
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 295
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Tidskriftsartikel (refereegranskat)abstract
- Distribution, sources, and ecological risk of 43 compounds of polycyclic aromatic hydrocarbons (PAHs) in surficial sediments of the Persian Gulf were investigated. The sediments were sampled from 60 offshore stations during an oceanographic cruise in the winter of 2012. Gas chromatography high-resolution mass spectrometry was used for the PAHs determinations in sediment samples. The concentrations of 21 parent PAHs, 7 methylated PAHs, 11 oxygenated PAHs and 4 nitrated PAHs were 9.0–201.5 ng g−1 dw, 3.3–60.3 ng g−1 dw, 15.2–172.7 ng g−1 dw and 0.1–8.3 ng g−1 dw, respectively. Among 21 parental PAHs, naphthalene (29.35 ng g−1 dw), phenanthrene (4.6 ng g−1 dw), and pyrene (3.18 ng g−1 dw) were the most abundant compound. 1-acenaphthenone (43.41 ng g−1 dw) and 2-methylnaphthalene (7.15 ng g−1 dw) showed the highest concentration in the oxy- and methyl-PAHs, respectively. The concentrations of nitro-PAHs were between not detected to 4 ng g−1 dw. According to the ecological risk assessment, the calculated total toxicity of PAHs was at below the lethal level on benthic organisms in all stations in the Persian Gulf, but there is risk of toxicity for the benthic organism in the Gulf of Oman (from the Strait of Hormuz to Jask). In general, nitrogenated and oxygenated derivatives did not show a significant risk in the study area. Based on the diagnostic ratios, the mixed sources (both petrogenic and pyrogenic) and pyrogenic sources have been identified for PAHs. Biomass combustion source has been identified for the stations near flares and gas fields. Principle component analysis-multivariate linear regression analysis for source identification shows that maritime traffic, abundant flares that burn the gas in oil, gas fields and dust storms have a major impact on the production of PAHs in this area.
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| 2. |
- Calderon, Blanca, et al.
(författare)
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Study of the presence of PCDDs/PCDFs on zero-valent iron nanoparticles
- 2017
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 169, s. 361-368
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Tidskriftsartikel (refereegranskat)abstract
- Studies show that nanoscale zero-valent iron (nZVI) particles enhance the formation of chlorinated compounds such as polychlorinated dioxins and furans (PCDD/Fs) during thermal processes. However, it is unclear whether nZVI acts as a catalyst for the formation of these compounds or contains impurities, such as PCDD/Fs, within its structure. We analyzed the presence of PCDD/Fs in nZVI particles synthesized through various production methods to elucidate this uncertainty. None of the 2,3,7,8-substituted congeners were found in the commercially-produced nZVI, but they were present in the laboratory synthesized nZVI produced through the borohydride method, particularly in particles synthesized from iron (III) chloride rather than from iron sulfate. Total PCDD/F WHO-TEQ concentrations of up to 35 pg/g were observed in nZVI particles, with hepta-and octa-chlorinated congeners being the most abundant. The reagents used in the borohydride method were also analyzed, and our findings suggest that FeCl3 effectively contains PCDD/Fs at concentrations that could explain the concentrations observed in the nZVI product. Both FeCl3 and nZVI showed a similar PCDD/F patterns with slight differences. These results suggest that PCDD/Fs might transfer from FeCl3 to nZVI during the production method, and thus, care should be taken when employing certain nZVI for environmental remediation.
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| 3. |
- Duong Phan, Ngoc Chau, et al.
(författare)
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Accurate sampling of PCDD/F in high temperature flue-gas using cooled sampling probes
- 2012
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 88:7, s. 832-836
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Tidskriftsartikel (refereegranskat)abstract
- In a laboratory-scale combustion reactor, flue-gas samples were collected at two temperatures in the post-combustion zone, 700 °C and 400 °C, using two different water-cooled sampling probes. The probes were the cooled probe described in the European Standard method EN-1948:1, referred to as the original probe, and a modified probe that contained a salt/ice mixture to assist the cooling, referred to as the sub-zero probe. To determine the efficiency of the cooling probes, internal temperature measurements were recorded at 5 cm intervals inside the probes. Flue-gas samples were analyzed for polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs). Samples collected at 700 °C using the original cooling probe showed higher concentrations of PCDD/Fs compared to samples collected using the sub-zero probe. No significant differences were observed between samples collected at 400 °C. The results indicated that artifact formation of PCDD/Fs readily occurs during flue-gas sampling at high temperatures if the cooling within the probe is insufficient, as found for the original probe at 700 °C. It was also shown that this problem could be alleviated by using probes with an enhanced cooling capacity, such as the sub-zero probe.Although this may not affect samples collected for regulatory purposes in exit gases, it is of great importance for research conducted in the high-temperature region of the post-combustion zone.
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| 4. |
- Jansson, Stina, et al.
(författare)
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Characterisation and fingerprinting of PCBs in flue gas and ash from waste incineration and in technical mixtures
- 2011
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 85:3, s. 509-515
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Tidskriftsartikel (refereegranskat)abstract
- Congener patterns of mono- to deca-chlorinated biphenyls (PC(1-10)B) were evaluated in (a) waste incineration flue gases collected in the post-combustion zone of a laboratory-scale fluidized-bed reactor, (b) ashes from two different MSW incineration plants, and (c) published data of eight Aroclor formulations. The congener patterns of the flue gases, ashes, and Aroclor mixtures clearly differed from each other, likely reflecting differences in formation pathways. The flue gas congener patterns were largely dominated by the least chlorinated congeners, whereas the ashes displayed more evenly distributed patterns. The most abundant congeners indicated a preference for 3,3',4,4'-oriented substitution, which may be related to de novo-type formation involving perylene. Principal component analysis confirmed that congener patterns differed among the three matrices and also distinguished flue gases collected at 200°C from those collected at 300°C and 450°C. This distinction could be partly explained by the degree of chlorination, although the substitution status of the ortho-position, and substitution in the 3,3',4,4'-positions also seemed to be influential. Injecting biphenyl into the post-combustion zone of the reactor did not alter the patterns, indicating that availability of the backbone structure is not a limiting factor for PCB formation.
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| 5. |
- Lundin, Lisa, et al.
(författare)
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Low temperature thermal degradation of PCDD/Fs in soil using nanosized particles of zerovalent iron and CaO
- 2013
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 91:6, s. 740-744
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the degradation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in contaminated soil using low temperature treatment (200-280°C) both alone and in combination with nanosized zerovalent iron (nZVI) particles or CaO. Control soil samples and soil fortified with nZVI particles or CaO were treated at 200 and 250°C in sealed glass ampoules. Treatment of the ampouled samples at 250°C was more effective than treatment at 200°C and the reduction in PCDD/F concentration was greatest when soil was treated at 250°C with nZVI addition (indeed, treatment at 200°C in the absence of nZVI resulted in increases in total PCDD and PCDD/F concentrations). In larger-scale experiments based on the obtained results, using a rotary furnace, the greatest reduction in total PCDD/F concentration was achieved by treating soil at 280°C, and adding nZVI to the soil resulted in almost no detectable PCDD/F in the gas phase.
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| 6. |
- Lundin, Lisa, 1976-, et al.
(författare)
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Reduction of PCDD, PCDF and PCB during co-combustion of biomass with waste products from pulp and paper industry
- 2013
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 91:6, s. 797-801
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Tidskriftsartikel (refereegranskat)abstract
- The use of waste wood as an energy carrier has increased during the last decade. However, elevated levels of alkali metals and chlorine in waste wood compared to virgin biomass can cause increased deposit formation and higher concentrations of organic pollutants. In this study, we investigated the effect of the ChlorOut technique on concentrations of organic pollutants. Ammonium sulfate was injected into the combustion system to inhibit formation of KCl (which causes deposits) and persistent organic pollutants, namely polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). The results showed that concentrations of the toxic congeners of PCDD, PCDF and PCB decreased in the presence of ammonium sulfate.
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| 7. |
- Lundin, Lisa, et al.
(författare)
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The behavior of PCDD and PCDF during thermal treatment of waste incineration ash
- 2011
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 84:3, s. 305-310
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Tidskriftsartikel (refereegranskat)abstract
- The polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) content of three fly ash samples with different elemental compositions from different municipal waste incinerators were analyzed before and after thermal treatment at 300°C or 500°C. Gas phase emissions during the treatments were also collected and analyzed. Substantial reductions in the total PCCD/F content of the ashes were observed after treatment at 500°C, seemingly due to degradation rather than dechlorination. Treatment at 300°C resulted in an increase in the PCDD/F content of the three ashes. Initial concentration of PCDD/F in the untreated ashes did not reflect the outcome of the treatment at the different temperatures. In addition, the composition of the ash was found to influence the rate of decomposition and formation of PCDD and PCDF during thermal treatment; the results showed that Cu, Fe, Ca and S play important roles in these processes.
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| 8. |
- Lundin, Lisa, et al.
(författare)
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The effects of fuel composition and ammonium sulfate addition on PCDD, PCDF, PCN and PCB concentrations during the combustion of biomass and paper production residuals
- 2014
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 94, s. 20-26
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Tidskriftsartikel (refereegranskat)abstract
- The use of waste wood as an energy carrier has increased during the last decade. However, the higher levels of alkali metals and chlorine in waste wood compared to virgin biomass can promote the formation of deposits and organic pollutants. Here, the effect of fuel composition and the inhibitory effects of ammonium sulfate, (NH4)2SO4, on the concentrations of persistent organic pollutants (POPs) in the flue gas of a lab-scale combustor was investigated. Ammonium sulfate is often used as a corrosion-preventing additive and may also inhibit formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). In addition to PCDDs and PCDFs, polychlorinated naphthalenes (PCN) and biphenyls (PCB) were also analyzed. It was found that the flue gas composition changed dramatically when (NH4)2SO4 was added: CO, SO2, and NH3 levels increased, while those of HCl decreased to almost zero. However, the additive's effects on POP formation were less pronounced. When (NH4)2SO4 was added to give an S:Cl ratio of 3, only the PCDF concentration was reduced, indicating that this ratio was not sufficient to achieve a general reduction in POP emissions. Conversely, at an S:Cl ratio of 6, significant reductions in the WHO-TEQ value and the PCDD and PCDF contents of the flue gas were observed. The effect on the PCDF concentration was especially pronounced. PCN formation seemed to be promoted by the elevated CO concentrations caused by adding (NH4)2SO4.
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| 9. |
- Lundin, Lisa, et al.
(författare)
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Thermal degradation of PCDD/F, PCB and HCB in municipal solid waste ash.
- 2007
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Ingår i: Chemosphere. - Oxford : Pergamon Press. - 0045-6535 .- 1879-1298. ; 67:3, s. 474-481
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Tidskriftsartikel (refereegranskat)abstract
- A thermal degradation procedure for reducing the concentrations of mono- to octa-chlorinated PCDD/Fs, PCBs and hexa-chlorobenzenes (HCB) in filter ash from incinerated municipal solid waste (MSW) is described. Thermal treatment of filter ash samples at 500 °C for 60 min in a closed system providing low oxygen conditions resulted in 97% and 99% reductions in the total and I-TEQ concentrations of PCDD/Fs, to 6.8 μg kg−1 ash and <0.05 μg I-TEQ kg−1 ash, respectively. Increasing the thermal treatment time to 480 min, at the same temperature, yielded 99% reductions in both total and I-TEQ concentrations of the mono- to octa-chlorinated PCDD/Fs. Similar effects were observed for HCB and PCBs. The data from this study indicate that PCDD/Fs and other toxic organic compounds in ash from incinerated MSW, can be effectively degraded by this procedure, which combines relatively low-temperatures, short treatment times, and low oxygen conditions.
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| 10. |
- Ortuno, Nuria, et al.
(författare)
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Emissions of PBDD/Fs, PCDD/Fs and PBDEs from flame-retarded high-impact polystyrene under thermal stress
- 2015
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 123, s. 64-70
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Tidskriftsartikel (refereegranskat)abstract
- The emissions of polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and their chlorinated analogues (PCDD/Fs) during the thermal treatment of a high impact polystyrene (HIPS) TV casing were investigated. The halogenated compounds were analyzed in the original material and in the gases emitted during its treatment at temperatures between 50 degrees C and 250 degrees C. DecaBDE was the primary PBDE in the TV casing, which also contained high levels of PBDFs (ppm range). At the lower treatment temperatures, non-modified PBDEs evaporated from the samples. Conversely, at 200 degrees C or above, debromination reactions led to the formation of additional tri- through nonaBDE. The formation of new PBDD/Fs was also detected in the gas phase when the plastic was heated to 200 degrees C or 250 degrees C, with higher yields of furans than dioxins. This appreciably increased the toxic equivalent (TEQ) levels of the gas phase relative to those seen in the untreated sample. In all cases, the levels and TEQ contributions from PCDD/Fs were negligible compared to those for brominated analogues. (C) 2014 Elsevier Ltd. All rights reserved.
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