| Summary: | 碩士 === 中國醫藥大學 === 環境醫學研究所碩士班 === 98 === Nonylphenol polyethoxylates (NPEOs) have been widely used as nonionic surfactants in industrial products and household applications. In the aquatic environments, NPEOs can be biodegraded into nonylphenol (NP) which is more stable and persistent. NP can mimic natural hormones and disrupt endocrine functions due to its structure similar to estrogen. However, NP has been measured and reported in aquatic environments but rarely in the atmosphere. A few literatures have reported the detection of NP in aerosols from the aeration tank of the sewage treatment plant. These findings have raised public concern of environmental pollution and human health. This study attempted to establish methods to collect samples and analyze NP in the aerosol generated from aeration tank and disinfection tank at a sewage treatment plant in Taiwan. In this study, 8-hour samples of aerosols were collected in Spring and May using a high-volume sampler ( 60 m3/hr). By the end of sampling, the sampling filters were wrapped with aluminum foil and stored at –70℃until analysis. The samples were extracted with dichloromethane in ultrasonic bath and then analyzed with high performance liquid chromatograph equipped with fluorescence detector. QA and QC were well done. The NP standard calibration showed R2＞0.995 and spike-test recovery = 95% (CV = 3.1%).
Results showed that the wind direction did not significantly affect the NP concentrations in the air samples taken from aeration tank unit ( p = 0.37). The correlation coefficients of temperatures and relative humidity associated with the NP concentrations in the air were 0.54( p = 0.11) and -0.46( p = 0.18). Also, the wind direction did not significantly affect the NP concentrations in the air samples taken from the disinfection tank ( p = 0.94). The correlation coefficients of temperatures, relative humidity and solar radiation associated with the NP concentrations in the air, were 0.26( p = 0.53), -0.45( p = 0.26) and 0.14( p = 0.73), respectively. We further simultaneously collected the sewage and aerosol samples at aeration tank unit for analyzing of the NP concentrations to estimate NP evaporated from water per hour. The rate of emissions was 3.13?n?慊/hr. In addition, the NP concentrations measured in the air at the administration building located in the downwind of aeration tank unit and used air pollution dispersion model to confirm the results of the measured values were consistent with the results of undetectable. Overall the mean NP concentrations in the air samples collected aeration tank and disinfection tank were 5.33±1.90 and 3.36±0.80 ng/m3, respectively.
In conclusion, NP exists not only in aquatic system but also in the air emitted from aeration tank and disinfection tank. The method established in this study was quick and convenient for estimating the NP concentration in the air. Therefore, this study has demonstrated a potential method to monitor the aerosol NP levels.
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