Hubertus Wichmann

Thermal formation of PBDD/F from tetrabromobisphenol A--a comparison of polymer linked TBBP A with its additive incorporation in thermoplastics.

For a long period, polybrominated flame retardants are under discussion because of the formation of polybrominated dibenzo-p-dioxins (PBDD)/dibenzofurans (PBDF) (PBDD/F) in case of thermal stress. Concerning polymer linked tetrabromobisphenol A (TBBP A), formation of PBDD/F was commonly presumed to be sterically hindered because of the covalent fixation into the polymer backbone. Combustion experiments with additively incorporated TBBP A compared with its polymer linkage revealed, that this assumption is incorrect and has to be revised. Under same conditions, similar PBDD/F concentrations in the range of 17.5-19.6 mg PBBD/F per kg TBBP A applied were analyzed. PBDD/F homologue distribution patterns were almost identical predominated by low brominated PBDF. These findings for PBDD/F formation have to be considered in future discussions regarding thermal stress caused by combustion or recycling processes, including other flame retardants bound in polymer matrix, e.g. polybrominated polystyrene (PS), or those with molecular structures showing less analogy to PBDD/F, like hexabromocyclododecane. The second aspect introduced, is the influence of different plastics on the formation rates of PBDD/F. In this context, combustion experiments were performed in an atmosphere consisting of synthetic air and HBr. PBDD/F concentrations were 8.47 mg/kg polyethylene, 1.67 mg/kg PS, 3.92 mg/kg phenolic resin and 18.1 mg/kg epoxy resin. Distribution patterns of PBDD/F homologues could partly be correlated with the occurrence of the precursors polybrominated benzenes and phenols.

Release of polychlorinated dibenzo-p-dioxins and dibenzofurans by setting off fireworks

Selected pyrotechnic articles were set off under laboratory conditions. Residues and vapors of smoke as well as unburnt charges were analyzed for polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) and their precursors chlorinated benzenes and phenols. The contamination of the selected products with these organic xenobiotics proved to be very variable. Remains of fireworks contained octachlorinated dioxins and furans up to 142 ng I-TEQ/kg as well as hexachlorobenzene in the range of 0.05 to 1,400 mg/kg. The deflagration of detonating compositions usually resulted in a dispersion of contaminants, whereas continuously burning flare compositions partially led to a thermal decomposition of organic pollutants. A significant rate of formation of polychlorinated dioxins and furans was observed when setting off blue-lightning rockets and fountains. Further investigations revealed that even high temperatures during the deflagration of black powder charges could not suppress the formation of PCDD/F from appropriate precursors.

Surface contamination with PASH, PAH and PCDD/F after fire accidents in private residences.

Surface samples were taken from two private residences after real fire accidents. The goal was, to determine the surface contaminations with polycyclic aromatic sulfur heterocycles (PASH), as representatives of a substance class, not investigated in this context, by now, polycyclic aromatic hydrocarbons (PAH) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). Analytical method for the determination of PASH was developed for the respective matrix. Concentrations measured ranged between 1.70 and 465 micrograms/m2 for PASH, 34.3 and 58,800 micrograms/m2 for PAH (EPA), and 4.15 and 1,300 ng/m2 for PCDD/F, as well. Obviously, PASH were formed during the fire accidents. Nevertheless, PAH were the most relevant pollutants after these small fires.

Release of PCDD/F and PAH during vehicle fires in traffic tunnels

Abstract Two cars, one subway carriage and one railway coach were combusted in a tunnel. A sampling strategy, specifically developed for these “fire accidents”, was employed to investigate the release of PCDD/F and PAH. Over a distance of several hundred metres, exponential decrease of contamination with an increasing distance from the fire spots could be traced, with surface concentrations ranging at [ng/m 2 ] and [μg/m 2 ]. On average, between 7 and 220 μg/kg PCDD/F were detected in the debris. It is estimated that a total of between 1.9 mg (car) and 567 mg (railway coach PCDD/F were formed during the fires. As a result of the car fires, the tunnel was contaminated with approximately 13 g and 27 g of PAH (EPA, respectively. Unlike the homologue distribution patterns, the isomer distribution patterns of the PCDD/F showed good conformity. The deposition behaviour within the above-mentioned groups of substances is quite different. Fire accidents, in which vehicles are involved, have to be followed up by decontamination and waste disposal measures adapted to the contamination situation.

Distribution behavior of heavy metals investigated in a laboratory-scale incinerator.

The distribution behavior of Pb, Cd, Fe, Cu, Mo and Zn was determined in a laboratory-scale incinerator. Points of interest were the influence of the temperature and combustion atmosphere on the emission rates of those metals, orientating at frequent combustion conditions of accidental fires. The experiments were carried out at 600 degrees C and 800 degrees C in N2, air, N2 + HCl and air + HCl atmospheres. Furthermore, the influence of the matrix (quartz, polyethylene and cellulose powder) on the distribution behavior of the heavy metals was investigated as well. It was determined whether the distribution behavior of Cu, Pb and Cd were affected by the other heavy metals. In conclusion, it was found that in air and N2 atmosphere a temperature increase from 600 degrees C to 800 degrees C and the addition of the matrix had no effect on the evaporation rates of the heavy metals, except for Cd. Addition of gaseous HCl led to increased evaporation of the heavy metals. The increase of the evaporation rates during the experiments with matrix was higher for Fe, remained the same for Pb, Cd, Zn, and lower for Mo and Cu compared to the experiments without matrix.

Influence of heavy metals on the formation and the distribution behavior of PAH and PCDD/F during simulated fires

Combustion experiments were performed with an artificial fire load (polystyrene and quartz powder) in a laboratory scale incinerator in the presence of gaseous HCl to simulate accidental fire conditions. The aim of this investigation was to trace back the alterations of the formation and the distribution behavior of PAH and PCDD/PCDF to the presence of CuO or a mixture of metal oxides (CdO, CuO, Fe(2)O(3), PbO, MoO(3), ZnO). The total amount of the 16 PAH target compounds was reduced by the factor of 5-9 when the mixture of metal oxides was present rather than merely CuO. PAH patterns as well as their distribution behavior were significantly influenced by these oxides. In general, transportation inside the installation was enhanced for most of the 16 analyzed PAH. Only fluorene and dibenzo[a,h]anthracene were transported to a smaller extent. In contrast to PAH, total concentrations of PCDD were increased by factor 9 and of PCDF by factor 10, respectively, when CuO was present. Adding the mixture of metal oxides resulted in an increase of PCDD by factor 14 and of PCDF by factor 7. CuO and the mixture of metal oxides had a different influence on the PCDD/F homologue patterns. For instance, the HxCDF to OCDF ratio after incineration without any metal oxide was 1 to 6, whereas addition of CuO or the mixture of the metal oxides shifted the HxCDF to OCDF ratios towards 1 to 40 or 1 to 17, respectively. Combustion along with CuO increased transportation of higher chlorinated PCDF congeners, whereas the mixture of the metal oxides caused a strong decrease of PCDF distribution throughout the system.

Dioxins and furans in the Jordanian environment Part 1: Preliminary study on a municipal landfill site with open combustion nearby Amman - Jordan

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in samples collected from the open-burnt municipal landfill site at Marka/Amman were analyzed. Six samples were collected from different locations distributed over the area of the landfill. The PCDD/PCDF concentrations ranged from 8.2 to 1,470 ng TEQ (BGA)/kg d.w. The total concentrations of PCDD/PCDF were between 685 and 112,300 ng/kg d.w. It was found that in all waste samples the total concentrations increased from Octa-CDD to Tetra-CDD and from Octa-CDF to Tetra-CDF.

Isolation and identification of tetrabromobisphenol-S-bis-(2,3-Dibromopropyl ether) as flame retardant in polypropylene

Abstract Approximately 4 % tetrabromobisphenol-S- bis -(2,3-dibromopropyl ether) and 0.44 % antimony were found in the back wall of a TV cabinet. This is the first time a bromoorganic flame retardant containing a sulfur linkage has been detected. No such compound has been previously mentioned in the analytical or environmental literature. Isolation from PP was performed by extraction and precipitation of coextracted polymer. After chromatographic separation (TLC, CC), the combination of 1 H 13 C-NMR, MS (EI), FT-IR and HPLC (UV/Vis, DAD and MS) indicated the TBBP-S derivative, which was verified by synthesis of reference material.

Chemical causes of the typical burnt smell after accidental fires.

The components responsible for the typical burnt smell that occurs after accidental fires (e.g. in buildings) were identified. For this purpose, samples of odorous materials were taken from different real fire sites. Their volatile fractions were analysed by means of thermal desorption, headspace analysis and solid-phase microextraction (SPME) combined with gas chromatography–mass spectrometry (GC/MS). Measurements performed with SPME gave the highest number of analytes as well as the highest signal intensities. A divinylbenzene/carboxen/polydimethylsiloxane SPME fibre was found to be the most suitable for this task. To distinguish the odour-active compounds from the ca. 1,400 identified volatiles concentrated by SPME, an olfactory detection port was attached to the GC/MS and the column effluent was assessed by panellists. The results revealed that eleven odorous compounds were present in most of the investigated samples: acetophenone, benzyl alcohol, 4-ethyl-2-methoxyphenol, 2-hydroxybenzaldehyde, 2-hydroxy-5-methylbenzldehyde, 2-methoxyphenol, 2-methoxy-4-methylphenol, 2-methylphenol, 3-methylphenol, 4-methylphenol and naphthalene. Their odour activities were confirmed in additional olfactory experiments, and the relative ratios of these eleven compounds were determined. Based on these ratios, standard solutions that presented an intense odour with typical characteristics of the burnt smell were produced.

Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction

In Europe, new cars had to be fitted with catalytic converters since 1993. Besides the desired air quality improvement, an accumulation of the catalytic active noble metals Pt, Pd, and Rh in the environment could soon be observed. This work aimed at a monitoring of platinum group element (PGE) emission and accumulation by comparing analytical data, all generated in 1999 and in 2005 and thus covering an important time span of vehicular exhaust catalysts introduction in Germany. A comparison of analytical results of 2005 with those of 1999 revealed a distinct increase of PGE concentrations in soils closely along heavy traffic roads mainly by a factor of 2–9 in the considered urban area located in northern Germany. At a crowded road in Braunschweig city with stop and go traffic, the highest soil concentrations were determined, namely 261 µg/kg for Pt, 124 µg/kg for Pd and 38.9 µg/kg for Rh. The investigations also revealed that especially Pt and Rh concentrations were comparably elevated in airborne dust in 2005. A sampling at the already mentioned roadside revealed airborne dust concentrations of 1,730 µg/kg for Pt, 410 µg/kg for Pd, and 110 µg/kg for Rh.