摘要：
近年来和田经济迅速发展及城市人口快速增长,汽车尾气、工业废气等各类污染物的城区排放量也在不断增加,加重了和田市大气污染.为评估和田市城区风速、沙尘天气对大气PM2.5毒性的影响,于2014年1月、4月、7月、10—11月采集大气PM2.5样品,应用质粒DNA评价法研究其PM2.5的氧化性损伤能力.结果表明,采样期间,和田市城区大气PM2.5质量浓度的变化范围为70~2489 μg·m-3,PM2.5质量浓度有随风速增大而增大的趋势.应用TD30(造成30% DNA损伤率所需的颗粒物剂量,μg·mL-1)值指示颗粒物氧化性损伤能力,结果表明,TD30越高,颗粒物氧化性损伤能力越弱,全样和水溶部分TD30值的变化范围分别为444~27480 μg·mL-1和481~20434 μg·mL-1;不论是全样还是水溶部分,其对质粒DNA的氧化性损伤均表现出随风速减小而增大的变化趋势;沙尘和非沙尘期间全样 TD30的平均值分别为9464 μg·mL-1和8008 μg·mL-1,而水溶部分分别为5494 μg·mL-1和7822 μg·mL-1,即沙尘期间采集的颗粒物对体外DNA的氧化性损伤小于非沙尘期间采集的样品,且非沙尘期间采集的样品的全样损伤大于相应的水溶部分样,而沙尘状况下体外DNA的氧化性损伤可能主要来源于水溶成分.全样和水溶部分的 TD30平均值与 PM2.5平均质量浓度之间存在明显的正相关趋势,说明颗粒物的质量浓度对DNA氧化损伤起着一定的作用.%In recent years, the rapid economic development of Hotan City and rapid population growth caused increase in air pollution from vehicles and industry. In order to evaluate the effect of dust whether on the toxicity of PM2.5of urban area, the PM2.5 samples were collected from January to December 2014 to analyze the oxidative capacity of the PM2.5particles by plasmid scission assay. The result showed that, the mass concentration of PM2.5ranged from 70 to 2 489 μg·m-3and which had been increased with the wind speed. The TD30(toxic dose of PM causing 30% of plasmid DNA damage, μg·mL-1) was used to indicate the oxidative capacity. The TD30values of whole and water soluble fraction of PM2.5samples were 444~27 480 μg·mL-1and 481~20 434 μg·mL-1, respectively. Both of the whole and water soluble fractions indicated that the lower the wind speed caused the higher the oxidative damage to plasmid DNA. During sand and non-sand period, the average TD30values of whole and water soluble fraction were 9 464 μg·mL-1and 8 008 μg·mL-1and water soluble were 5 494 μg·mL-1and 7 822 μg·mL-1respectively. The oxidative damage of whole particles were higher than their corresponding water-soluble fractions during the non-dust storm period, on contrast, the toxicity of the particles was mainly sourced from their water soluble fraction during the dust storm period. Both of the TD30in whole and water soluble fraction positively correlated with PM2.5mass concentration indicated that the mass concentration of PM2.5played an important role in oxidative damage.
