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目的研究杭州市春夏季大气细颗粒物(PM2.5)的污染状况及其细胞毒性。方法采用PM10 PM2.5-2型颗粒物采样器和重量法收集2005年春季(4—5月)和夏季(7—8月)大气PM2.5样本,采样地点位于杭州市中心。选择WI-38人胚肺细胞株,将春季和夏季大气PM2.5样本分别以25、50、100、200、500μg/ml染毒细胞24 h,并以等量三蒸水为溶剂对照组,采用克隆形成率法测定PM2.5的细胞毒性。结果以2006年美国EPA新颁布的大气环境质量PM2.5标准(0.035 mg/m3)为参考,杭州市春、夏两季超标天数百分率分别为96.7%和90.0%;以1997年颂布的标准(0.065 mg/m3)为参考,分别为33.3%和20.0%。春季大气PM2.5样本染毒细胞,染毒剂量为25、50、100、200、500μg/ml,相对克隆形成率分别为99.6%,96.2%,85.0%,73.8%和54.6%;夏季大气PM2.5样本染毒细胞,染毒剂量为25、50、100、200、500μg/ml相对克隆形成率分别为97.0%,96.9%,88.0%,83.0%和64.7%;相对克隆形成率随着处理剂量的增加而递减,呈现明显的剂量-反应负相关关系。除夏季大气PM2.5样本25与50μg/ml组细胞相对克隆形成率差异无统计学意义外,其余各组间及组内比较,差异均有统计学意义(P<0.01)。结论杭州市大气存在一定程度的PM2.5污染,春季较夏季严重。春季大气PM2.5样本的细胞毒性高于夏季。
Objective To study the pollution status and cytotoxicity of PM2.5 in spring and summer in Hangzhou. Methods Atmospheric PM2.5 samples from spring 2005 (April to May) and summer (July to August) were collected by PM10 PM2.5-2 particle sampler and gravimetric method. The sampling sites were located in the center of Hangzhou. WI-38 human embryo lung cell line was selected, and the PM2.5 in spring and summer were exposed to 25, 50, 100, 200 and 500 μg / ml respectively for 24 h. The cytotoxicity of PM2.5 was determined by clonogenic assay. Results Based on the PM2.5 standard of atmosphere quality (0.035 mg / m3) newly promulgated by the U.S. EPA in 2006, the exceeding percentage days in spring and summer in Hangzhou were 96.7% and 90.0% respectively. Based on the standards promulgated in 1997 (0.065 mg / m3) as reference, respectively 33.3% and 20.0%. In spring, the PM2.5 samples were exposed to a dose of 25, 50, 100, 200 and 500 μg / ml respectively, and the relative clonogenic rates were 99.6%, 96.2%, 85.0%, 73.8% and 54.6% .5, the relative clone formation rates were 97.0%, 96.9%, 88.0%, 83.0% and 64.7% at 25, 50, 100, 200 and 500μg / ml respectively. Dose increase and decrease, showing a significant dose-response negative correlation. There was no significant difference in the relative colony formation rate between the 25 and 50 μg / ml PM2.5 samples in the summer and between the other groups and the groups (P <0.01). Conclusion There is a certain degree of PM2.5 pollution in the atmosphere of Hangzhou City, which is more serious in spring than in summer. PM2.5 spring air samples cytotoxic higher than in summer.