Exhaust fumes of paraffin, beeswax and stearin candles without any further paint or decorative element were analysed for the toxicological important substance classes of PCDD/PCDF, PAH and short chain aldehydes. The candle waxes and wicks were investigated for chlorinated dioxins, furans and some known precursors. Toxicological risk assessment shows that emissions of the investigated candles are much lower than all administrative limitation values — even under “worst case conditions”. Thus, they do not produce a toxicological risk for human health. 相似文献
Im Rahmen eines Untersuchungsprogrammes zur Schadstoffemission von Paraffin-, Stearin- und Bienenwachskerzen ohne Farb- und
Lackbeimischungen wurden sowohl die Wachse und Dochte als auch die Brandgase dieser Kerzen auf die toxikologisch besonders
relevanten Schadstoffklassen der PCDD/PCDF, PAK und kurzkettigen Aldehyde untersucht. Die toxikologische Bewertung kommt selbst
bei einem angenommenen „worst case“-Szenario und unter Berücksichtigung von geltenden Grenz- und Richtwerten zu dem Ergebnis,
da? von den untersuchten Kerzen kein zus?tzliches Gesundheitsrisiko ausgeht.
Exhaust fumes of paraffin, beeswax and stearin candles without any further paint or decorative element were analysed for the
toxicological important substance classes of PCDD/PCDF, PAH and short chain aldehydes. The candle waxes and wicks were investigated
for chlorinated dioxins, furans and some known precursors. Toxicological risk assessment shows that emissions of the investigated
candles are much lower than all administrative limitation values — even under “worst case conditions”. Thus, they do not produce
a toxicological risk for human health. 相似文献
The presence of Persistent Organic Pollutants (POPs) is identified as a global problem for humans and the environment. POPs, in fact, are released by numerous static, mobile and diffuse sources, and are frequently seen to be widespread. Due to the global dimension of the potential environmental impacts, POP related problems can only be handled on the basis of international agreements. Concerning this aspect, some international activities are presented and general requirements are discussed in view of the international POPs management, both for static and diffuse releases 相似文献
A simple, rapid, and efficient dispersive liquid–liquid microextraction method, followed by UV–Vis spectrophotometry was developed for the preconcentration and determination of Pd ions in water samples. Pd ions react with α-furildioxime (chelating agent) to form a hydrophobic complex. Various parameters were altered to study and optimize their effects on the extraction efficiency, such as pH, ligand concentration, the type and volume of extraction and dispersive solvents, extraction time, and salt concentration. Under optimized conditions, the method exhibited an enrichment factor (Corg/Caq) of 25 and recovery more than 98 % within a very short extraction time. The linearity of the method ranged from 10 to 200 μg?L?1. The limit of detection was 1.1 μg?L?1. The relative standard deviation for the concentration of 100 μg?L?1 of Pd was 2.3 % (n?=?10). Finally, the developed method was successfully applied to the extraction and determination of Pd in tap, river, mineral, and sea water samples. 相似文献
Pollution and destruction of the environment due to the accumulation of non-degradable plastics are some of the most important concerns in the world. A significant amount of this waste is related to the polymers used in food packaging. Therefore, experts in the food industry have been looking for suitable biodegradable alternatives to synthetic polymers. Preparing biocompatible and biodegradable films based on starch is a good choice. In this study, various factors affecting films of starch/polyvinyl alcohol (PVA)/containing ZnO nanoparticles such as the amount of starch, PVA, glycerol, and ZnO were evaluated by response surface methodology (RSM). Film formation by solvent casting method, mechanical properties, swelling, solubility, and water vapor permeability (WVP) were selected as responses of RSM. The results showed that hydrogen bonding interactions between polyvinyl alcohol and starch improved the film formation. The effect of glycerol and PVA content on the mechanical strength was contrary to each other. As the amount of PVA increased, the tensile strength first decreased and then increased. The value of WVP was for all Runs from 0 to 6.77?×?10??8 g m??1 s??1 Pa??1. Finally, films with high film formation, maximum tensile strength, and high elongation at break, minimum solubility, permeability, and swelling were optimized.
In Nuremberg (Germany), each year about 25,000 tons (dry matter) of sewage sludge are obtained as by-product of waste water treatment. The digested sludge consists of 96% water. Until 1992 it was thermally stabilized using the Porteous procedure: the sludge was heated in an autoclave up to a temperature of 180–200 °C at a pressure of 28 bar. After pressure reduction and moving to a thickener, a substantial part of the liquid could be removed. After running through a chamber filter, the sludge contained only about 50% dry matter. This treatment does not only remove water; organic matter is also degraded or evaporated. Between November 1991 and May 1992, the sludge was analyzed four times before and after the drying process and examined for heavy metals (Pb, Cd, Cr, Cu, Ni, Hg, Zn), polychlorinated biphenyls (PCB) and PCDD/F. The concentration of heavy metals and PCB (related to dry matter) increased by a faktor of 1.3 after the drying process. This effect may be explained by the decrease of organic matter during drying. In the case of PCDD/F, the ITQ increased by a factor of 3.2, for some congeners even by a factor of 8. The only explanation can be that during thermal conditioning PCDD/F is formed by precursors as chlorophenols. This formation is probably catalyzed by metals as copper or nickel and sped up by the higher temperatures. 相似文献