OCR Text |
Show shown in Table 1. During the extraction process, samples were placed and extracted in a soxhlet extractor with 250 ml of dichlormethane at 40°C for about 16 hrs. After the extraction process, the dichloromethane residue was concentration to 1 ml - 2 ml by using a rotory evaportor. The extract residue was purified with 100 ml of hexane-dichloromethane (7:3, v/v) in the tube purifier(D=l cm, L=20 cm) which was packed with 2 grams of activated aluminum and 3 grams of silica gel. Finally, the purificatory samples were concentrated to 2 ml by using a rotary evaportor, and dried to 1 ml by using nitrogen. The mutagenic activity of the particulates and PUF extracts were tested by the Ames Salmonella/microsomal assay system. From the mutagenicity research of ambient particles, it was noted that the mutagenic response of strain TA98, which was used to detect frame-shift substitution mutation, was significantly higher than that of strain TA100, which was used to detect base-pair substitution mutation, upon incubation with the dichloromethane extract residue of airborne particulates. Thus, Salmonella typhimurim strain TA98 was employed to carry out the mutagenicity test in this study. An aliquot of sample extracts in D M S O was placed in a test tube containing 2 ml of molten top agar supplemented with a 0.1 ml test solution, 0.1 ml of an overnight broth culture of the tester strain, and with or without 0.5 ml of S9 mixture. The S9 homogenate was prepared from the liver of Sprague -Dawley malerats pretreated for 5 days with Aroclor 1254 (500 mg/kg body weight) according to Maron and Ames et al.[14]. After 2 days incubation of the culture plates at 37 °C, histidine revertants of TA98 were scored. RESULTS AND DISCUSSION From this investigation, when the thermal temperature of the first stage incinerator was at 350 - 450 °C, polystyrene was decomposed by the mechanisms of random-chain scission and end-chain scission. The long chain of polymer structure was broken down to a shorter chain structure, i.e., styrene monomer, dimer, trimer and toluene. When the intermediate-products from the first stage incinerator were introduced to the second stage incinerator, the intermediate-products should be |