利用SPMD技术监测珠江三角洲大气有机氯农药

利用半渗透膜装置(SPMD)对珠江三角洲地区大气有机氯农药(OCPs)进行了分季度为期1年的监测分析。结果显示,该地区大气OCPs主要为DDTs,HCHs,氯丹和甲氧基氯,DDTs的含量约占总量的62%～88%。珠江三角洲地区大气有机氯农药时空分布差异明显,OCPs含量夏季高于冬季;各地区大气有机氯农药的年均含量为3 8～27 5ng d,香港和珠海较低(平均为5 0ng d),广州(GZ01)最高,年均值达27 5ng d。大气中m(DDT) m(DDD+DDE)均大于1,表明近期该地区大气中仍有新的DDT输入,对α-HCH和α-氯丹的手性特征进行了分析,它们的旋光异构体比值(年均值)(ER(+-))分别为0 75和0 69。夏季大气与土壤中α-HCH的ER(+-)相当,而冬季大气ER(+-)要低于土壤,表明夏季大气α-HCH基本来自于土壤中α-HCH的挥发,而冬季大气α-HCH可能来自土壤挥发与外来源迁移的组合。 

Monitoring OCPs in the Air Using SPMD in the Pearl River Delta

Semipermeable membrane devices (SPMD) were deployed in the Pearl River Delta (PRD), South China, to monitor the seasonal variations of organochlorine pesticides (OCPs) in the air for a year. Results showed that the OCPs compounds in the sampling areas were mainly DDTs, HCHs, chlordane and methoxychlor. DDTs in all samples comprised 62% to 88% of the total amount of OCPs. The distributions of OCPs in the air were characterized by temporal and spatial difference in the PRD. The OCPs concentrations were higher in the summer than in the winter. The annual average concentrations of OCPs ranged from 3.8～27.5 ng/d in different areas, with lower values in Hong Kong and Zhuhai (averaged 5.0 ng/d) and higher values in Guangzhou (GZ01, averaged 27.5 ng/d). The high ratio (>1) of m(DDT)/m(DDD+DDE) possibly indicated that there were still fresh DDT emitted into the atmosphere. The annual average enantiomeric compositions (ER(+/-)) of α-HCH and α-Chlordane were 0.75 and 0.69, respectively. The ER(+/-) value of α-HCH in the air was equivalent to that in the soil in the summer but lower than that in the winter. It is suggested that the atmospheric α-HCH in the summer were mainly from soil evaporation, while transported α-HCH may contribute significantly in the winter.