珠江口现代沉积物柱芯样多环芳烃高分辨沉积记录研究

Depositional history record of polycyclic aromatic hydrocarbons in core sediments from Pearl River estuary, China

通过对采集于珠江三角洲澳门河口区的沉积物柱状样品中多环芳烃的GC MS定量分析测定,并结合210Pb同位素定年分析,重建了珠江口近代有机污染物的污染史(1959～1996年).研究结果表明,柱芯样品中多环芳烃的浓度为0.6～4.5μg·g-1(干重计),污染程度为中等.其中在20世纪60年代和80年代分别记录到两个高的污染峰,表明这两个时间段内有较大的污染物输入.以母体化合物比值对沉积物样品中的多环芳烃来源进行了分析,结果表明是受到了以油类和不完全燃烧产物为主的混合污染,且污染来源较为单一.对沉积物毒性潜在效应的计算表明,表层沉积物毒性效应较大,且从90年代初期开始后至1996年,毒性当量浓度呈线性趋势增加.

The polycyclic aromatic hydrocarbons in a core sediment collected from Macao Estuary of Pearl River were quantificationally analyzed by GC/MS. The pollution history of PAHs in this area was reconstructed by analysis of the concentration of PAHs connected with the deposition time by ^(210)Pb isotope dating method (1959—1996). It was shown that Phenanthrene, alkyl substituted Phenanthrene, Perylene, Fluoranthene and Benzo[b]]fluoranthene and Benzo[k]]fluoranthene were dominated in most layers in the core sediments. The results indicated that the total concentration of PAHs in the core sediment ranged from 0.6 to 4.5μg·g^(-1)(dry weight). It revealed that the sediments had been mildly contaminated by PAHs during 1959—1996.The historical record of PAHs contamination in the sediment showed that two contamination Peaks which represented the input time in 1960s and 1980s,respectively.Depth profiles in Macao Estuary, Pearl River indicated higher concentrations of PAHs in the surface sediment. Based on the characteristics of parent ratios of PAHs, The contamination sources of the core sediments were also discussed. The areas were contaminated by a mixing pollution of combustion and petroleum. The potential effects of toxicity of the sediment were calculated by toxicity equivalent factors, the toxicity equivalent concentrations of PAHs in the sediments showed higher concentration of PAHs in surface. And it was also noted that it had been increased at linear relation-ship for the concentration of toxicity equivalent concentrations from the end of last century to 1996. Such the toxic organic pollutions merit concern in the areas.