摘要
作为一种新型的氯代阻燃剂,得克隆(dechlorane plus,DP)已成为全球广泛存在的污染物,为研究其在北太平洋及北冰洋的分布及迁移规律,运用GC-NIC-MS测定了2012年中国第五次北极航次大气与表层海水中DP异构体的含量。结果显示,DP在所测样品中普遍存在,大气和表层海水中总DP浓度变化范围分别为0.403~15.993 pg/m3、0.0131~0.2175 pg/L,且亚洲沿岸(北纬40°左右的)DP浓度较高,北冰洋DP浓度相对较低。大气样品中fanti值(anti-DP比率)为0.01~0.49,且随着北半球纬度的增加呈下降趋势,说明大气长距离传输过程中syn-DP比anti-DP更稳定,anti-DP发生立体选择性的降解;许多研究中指出高纬地区海水中DP的主要来源为大气远距离传输及其沉降,污染物多具有与大气相近的组成比,但本次研究中海水与大气样品fanti不具有相关性(p>0.05),组成差异较大,其可能为受大洋环流远距离传输和海洋环境中DP生物降解、沉积物吸附等环境行为综合影响结果。深入分析北太平洋和北冰洋DP组成特点和分布特征,发现大气和海水远距离传输为北冰洋地区DP的主要来源。
As a chlorinated flame retardant,Dechlorane Plus(DP) was globally ubiquitous.To assess the distribution and migration law of DP in the North Pacific and the Arctic Ocean,DP in air and surface seawater was detected by gas chromatograph coupled with a mass spectrometer(GC-NIC-MS) during the Chinese Arctic cruise.The results showed that DP was detected in all atmospheric and seawater samples.The concentrations of DP ranged from 0.403 to 15.993 pg/m3 and 0.0131 to 0.2175 pg/L in air and seawater,respectively.The concentration of DP was higher in the coast of the Asia than that in the Arctic Ocean.The fractional abundance of the anti isomer(fanti) was ranged from 0.01~0.49 and decreased with increasing northern latitude,which indicated that a stereoselective depletion of the anti isomer during long-range atmospheric transport(LRAT).It had reported that long-range atmospheric transport and deposition were main sources in seawater at high latitudes where DP had similar composition ratio in seawater and air.However,in this research,the fanti of seawater samples had no significant correlation with that of atmospheric samples(p>0.05) which indicated that the distribution of DP isomers in seawater were influenced by micro-degradation、adsorption of sediments and so on.Comparing the composition and distribution of DP in the North Pacific and the Arctic Ocean,we found that LRAT and sea water transport were two main sources of DP in the Arctic.
引文
