淮河中下游沉积物PAHs的稳定碳同位素源解析

Compound-Specific Stable Carbon Isotopic Analysis on Origins of PAHs in Sediments from the Middle and Lower Reaches of the Huaihe River

对淮河中下游水相、悬浮物、沉积物中的PAHs(多环芳烃)进行定量分析,在探讨其分布特征的基础上,利用单体烃稳定碳同位素技术揭示研究区沉积物中PAHs的来源.结果表明:水相中正阳关的ρ(PAHs)最高,达5.01 ngmL;悬浮物和沉积物中以蚌埠闸的w(PAHs)最高,分别为9.85和1 175.02 ngg.沉积物中PAHs的δ13C在-39.4‰～-17.6‰之间.正阳关、平圩、洛河和蚌埠闸等采样点的高环PAHs的δ13C比低环PAHs的小,表明高环PAHs富集12C(轻碳同位素),显示燃煤源为主要污染源;但这4个采样点PAHs的δ13C与燃煤烟尘相比存在一定差异,表明除燃煤源外可能还存在着少量其他污染源.双沟镇高环PAHs的δ13C比低环PAHs的大,表明高环PAHs富集13C(重碳同位素),可能是微生物作用所致.

PAHs contents in water,suspended particulate matter and sediments from the middle and lower reaches of the Huaihe River were analyzed quantitatively,and the primary sources of PAHs in the sediments were identified by compound-specific stable isotope analysis.The results indicate that： 1） the PAHs concentrations（up to 5.01 ng/mL） in the water at the Zhengyangguan site was the highest among all the samples.2） Bengbuzha was the most polluted site,with PAHs concentrations of 9.85 ng/g in the suspended particulate matter and 1 175.02 ng/g in the sediments.δ^13C in the sediments varied between-39.4‰ and-17.6‰.^12C-depleted values recorded for high molecular weight PAHs were consistent with a dominant PAHs source of coal combustion at the sites of Zhengyangguan,Pingwei,Luohe and Bengbuzha.In addition,the isotopic signatures for those sampling sites were slightly different as compared with those from soot from coal combustion.Coal combustion might play the most important role in PAHs inputs,and a few other sources might included;other sources might include ship and vehicle emissions.Meanwhile,the isotopic trend of PAHs in the Shuanggouzhen site might be mainly ascribed to biodegradation,which was indicated by the enrichment of ^13C in the high molecular weight PAHs.