| Research Abstract |
We obtained 2,0 ambient air samples of continuous 7days collecting during a period of July of 2000 to November of 2001 on the campus of Setsunan University, Hirakata, Osaka, Japan, using a newly developed low-volume air sampler with the flow rate of 40 L/min. These air samples were all analyzed for dioxin analogues including polychlorinated dibenzo-p-dioxins (PCDDS), polychlorinated dibenzofurans (PCDFs) and coplanar PCBS (Co-PCBs) using our developed analytical method, which was essentially composing of an addition of 13C-laveled internal standards, extraction with toluene or ace tone under reflux, refined by multi-layer silica gel column chromatography and alumina column chromatography and analysis for dioxin analogues in EI-SIM mode at a high resolution gas chromatograph -mass spectrometer (GC/MS). Consequently, it was first revealed that the air pollution level with dioxin analogues was rather higher during a period of spring to summer seasons and was lower duri ng of winter season
… More
. This phenomenon was completely contrary to many data previously reported by many researchers, all of which were derived from limited analytical data such as several times per year. In addition, it was made clear that the weekly alteration of air pollution was considerably large with a level of maximum/minimum ratio of ca. 6 throughout this experiment time.
On the other hand, Japanese pine needle samples collected weekly during this experimental period. The gas phase of dioxin analogues in the air was confirmed to mainly accumulate in the pine needle. In addition, the accumulation level was also made clearly to have a good positive correlation with an increase of needle age.
From these results, we produced a simple assessment formula of air pollution level of dioxin analogues on the basis of the analytical data of pine needle. The method application for three areas i n Osaka Prefecture, central Japan gave a good result.
In the meanwhile, a joint research of our group and Environmental General Institute, Tokyo was also made clear that the bio-monitoring data by pine needle as an indicator of dioxin analogues in th e air agreed with the simulation result of air pollution by computer, indicating the bio-nionitoring to insist a suitable technique for assessment of air pollution with dioxin analogues.
Furthermore, we revealed the existence state of persistent organo-pollutans including DDT analogues, HCH analogues, chlordane and hexachlorobenzene in the air through the analytical data of air samples collected by the low-volume air sampler, showing the majority of these pollutants to be present as a gas phase. Less
|
