OCR Text |
Show studied[ll]. the results showed that mutagecicities of PAHs without a bay region were largely independent of the source of activating enzyme. Some researches indicated that nucleophilic epoxides were formed from a metabolic oxidation of PAHs and then the epoxide ring would react with an nucleophilic group in celluar DNA. With its D N A thus altered, the cell was unable to reproduce normally[12]. According to the experimental results of a prototype /laboratory-scale rotary kiln under suboptimal operation conditions, Demarini (1992) suggested that the mutagenic emission factors may depend as much as more on the operating conditions of the incinerator than on the feed stock[13]. The objectives of this research work are focused on investigating the mutagenicity and PAHs in air emissions from the incineration of polystyrene with various metallic salt additives under variuos stage-two temperatures sand oxygen supplies. MATERIALS AND METHODS The 0.2 gram of polystyrene (P.S.) was incinerated at various temperatures and with various oxygen supplies in the two-stage incinerator. The two-stage incinerator consisted of two furnaces, two quartz tubes(D=3 cm, L=30 cm and L=50 cm). The feed gas, which consisted of oxygen and nitrogen, was firstly introduced through two tubes (D= 5.0 cm, L= 30 cm) of 1 M BaCh or 3 M NaCl solution, then carried BaCl2 (1.3 * 10"6 mmole/sec) or NaCl (1.1 * 10*5 mmole/sec) into the second stage incinerator. The feed rate was controlled at 2.0 NL/min and at various oxygen ratios by using the flotation flow meter and needle valves. The rate of temperature increase in the stage-one incinerator was controlled at 35-40 °C/min, and the maximum temperature was controlled at 500 °C. The temperature in the stage-two incinerator was controlled from 700 °C to 1200 °C. The glassfiber filter was used for sampling the particulates and PAHs which were defined in the solid phase. PUF (polyourethane foam) was used for sampling the PAHs which were defined in the gas phase. The samples were pretreated in a series process: extraction, concentration and purification. Then the GC/MSD (HP 5890-11, H P G1034C M S Chemistation; NIST/EPA/NIH Mass Spectral Database-Envelop) was used to analyze the 14 species of PAHs as - 2 - |