壬基苯酚聚乙氧基醇類(nonylphenol ethoxylates, NPEOs)為非離子界面活性劑，廣泛使用於工業產品及家庭用的清潔劑產品。當其排放到水體環境，經過生物降解而形成穩定性及持久性的壬基苯酚(nonylphenol, NP)。由於NP其分子結構與動物及人體內的雌激素相似，容易造成人體內分泌系統功能的干擾。然而國內外都較缺乏空氣中NP的濃度分佈之相關研究。國外文獻指出，在污水處理廠的曝氣池可以檢測到含有NP的氣膠，使得大家更加關切環境中NP對人類健康影響的議題。因此本研究將會進行污水處理廠中曝氣池及消毒池單元的空氣採樣，期盼可以建立大氣中NP的採樣與分析的方法，進行定性與定量大氣中的NP的濃度。在污水處理廠之曝氣池單元中，使用高流量採樣器進行 8小時的採樣 (流速 60 m3/hr)。採樣完後使用鋁箔紙包覆濾紙樣本置於 -70℃下保存。濾紙樣本使用二氯甲烷溶液搭配超音波震盪進行萃取，最後使用高效率液相層析儀搭配螢光分光光度計進行定性與定量分析。將NP溶於甲醇做序列稀釋的檢量線的 R2 大於 0.995。添加已知濃度的標準品到樣本求得分析方法的回收率為 95% (CV = 3.1%)。在環境變項的探討，風向對於曝氣池單元氣膠中NP濃度沒有顯著影響( p = 0.37)，而溫度與相對濕度對氣膠中NP濃度的相關係數分別為0.54( p = 0.11)與-0.46( p = 0.18)；而在消毒池單元，風向同樣未顯著影響氣膠中NP的濃度( p = 0.94)，而溫度、相對濕度與太陽輻射量對NP濃度的相關係數則分別為0.26( p = 0.53)、-0.45( p = 0.26)與0.14( p = 0.73)。進一步，同時採集曝氣池單元污水與氣膠樣本，進行NP的濃度分析，推估曝氣池單元水體中的NP於每小時揮發至空氣的速率為3.13 ?慊/hr。此外，位於曝氣池單元下風處80公尺的行政大樓，其區域氣膠中NP濃度的實測值與均勻源強的面源模型模擬出的預測值做比對，結果實測值為N.D，符合模型推算之結果。綜觀研究結果，求得曝氣池及消毒池單元氣膠中的NP濃度分別為 5.33 ± 1.90 和 3.36 ± 0.80 ng/m3，並且可以得知NP 不僅存在水體環境，也會存在於污水處理廠裡曝氣池及消毒池單元的空氣中。除此之外，使用本研究方法可以簡便及快速的評估空氣中NP的濃度，因此本研究具有提供監測空氣中NP 濃度分佈的分析方法之潛力。
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.
