| Summary: | 博士 === 國立成功大學 === 環境工程學系 === 89 === This study was undertaken to collect on site and quantify the emissions of toxic compounds released from athletic running tracks. Two major topics were involved in this study.
In the first part of this study, three typical types of tracks, one synthetic rubber and two tracks (types II and I) consisting mainly of polyurethane, were studied. They were all installed with adhesives and backings, both of which contributed significant amount of VOCs. VOCs released from the track surfaces were collected with a flux chamber and subsequently analyzed by a gas chromatograph/ mass spectrometer (GC/MS). Also, for each track and at each selected time the emission flux and mass emission were measured on site under outdoor conditions over a period of forty minutes.
GC/MS analyses show that the VOCs emitted include 2-methyl furan, butanal, methyl ethyl ketone, benzene, heptane, methyl isobutyl ketone, toluene + octane, hexanal, nonane + ethylbenzene, xylenes + styrene, propyl benzene, decane, 1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, 1,2,3-trimethyl benzene and undecane. Of these, hexanal was the common and principal compound for all three types of tracks. 2-Methyl furan and methyl isobutyl ketone were the characteristic compounds for the synthetic rubber and the type II of polyurethane tracks, respectively. In field studies, no unique compounds were found in the type I of polyurethane tracks.
For each of these three types of tracks the total-VOCs emission flux was correlated to the track age and track surface temperature. The results of multiple regression analysis showed good correlation. The type II polyurethane track had the highest decay rate in emission, while the synthetic rubber track had the lowest.
Two years after the track installation, the VOC concentrations measured at the breathing height of school children, were not significantly higher than the background levels. Further studies on other toxic materials emitted from new athletic tracks, including VOCs and Semi-VOCs (such as polycyclic aromatic hydrocarbons, PAHs) and starting from track installation, are suggested.
In the second part of this study, loss of PAHs in methylene chloride during evaporation with a stream of nitrogen was systematically studied. The starting sample concentration levels were 0.167 µg/ml and 0.00333 µg/ml for each PAH. These two sets of test solutions were both evaporated from 300 ml to final volumes of 50, 30, 5, 3, and 1 ml, with a constant stream of nitrogen and in a water bath kept at 40 oC. Each sample was analyzed by GC-FID (Gas Chromatograph/Flame Ionization Detector).
Factors affecting the percentage of analyte recovery include boiling points of analytes, the final sample volume and the starting sample concentration. When the diluted solutions were reduced from 300 ml to 1 ml, the recoveries for PAHs were all higher than 90%. However, when the concentrated solutions were evaporated to 1 ml, recoveries of all analytes dropped below 85%, and naphthalene, the most volatile PAH, dropped to 77.5%. If evaporation was halted to a final volume of 3-5 ml, the recovery for PAHs in both concentrated and diluted solutions were still almost all higher than 90%. This implies that during evaporation of methylene chloride with a nitrogen stream, no significant losses of semivolatile analytes, regardless of their boiling points or concentration levels, were found until or unless the final volume reaches below 3-5 ml.
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