Bestimmung und Bewertung der Emissionen von PCDD/PCDF, PAK und kurzkettigen Aldehyden in den Brandgasen von Kerzen Untersuchung von Wachsen und Dochten — Bestimmung der Emissionen aus den Brandgasen von Kerzen — Toxikologische Bewertung

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.     

Effects of ownership status,weight asymmetry,and case fit on the outcome of case contests in two populations of Agrypnia pagetana (Trichoptera : Phryganeidae) larvae

Summary The contest behavior of larvae from a dense and a sparse population of the caddisfly Agrypnia pagetana was studied in the laboratory. Fights were generally of short duration, and most fights were won by owners in both populations. Take-over contests lasted longer than non-takeover ones, indicating that owners in general used a more persistent strategy. Ownership was more important in the sparse population than in the dense population, but contest duration did not differ between the two populations. Effect of weight asymmetry was most pronounced in the dense population, and here the larger larvae usually won. However, when the intruding larvae were much larger than the owner, a low number of take-over contests were probably related to the inferior fit (low resource value) of small cases to the intruding larvae. In both populations the frequency of case takeover contests was low when the case fit to the intruder was low. We conclude that A. pagetana larvae use fighting strategies typical for contests over resources of low value relative to contest costs.