Feng Jing-lan, Niu Jun-feng
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Huan Jing Ke Xue. 2007 Jul;28(7):1573-7.
Sediments collected from Yangtze River were separated into five size fractions ( > 200 microm, 200 - 125 microm, 125 - 63 microm, 63 - 25 microm, <25 microm) by wet sieving. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) listed as U.S. EPA priority pollutants were determined in the fractionated sediments. Sigma PAHs concentrations ranged from 26.1 to 7135.9 ng/g and varied largely among the different size fractions. The highest Sigma PAHs concentration (7135.9 ng/g) was associated with the largest size fraction ( > 200 microm) while the fine silt fraction (63 - 25 microm) contained the lowest Sigma PAHs concentration, 26.1 ng/g. Although the PAHs concentrations difference among different fractions was great, the composition of PAHs in the five size fractions showed similar pattern dominated by PAHs with three or more rings. Sediment particles less than 25 microm contributed 75% of the Sigma PAHs, while comprising 38.6% of bulk sediment dry weight. A significant positive correlation (p < 0.01) between PAHs and total organic carbon (TOC) existing for all size fractions demonstrated that TOC was important for PAHs distribution in sediments. Additionally, sediment organic matter type and structure also played an important role in PAHs distribution in different grain size fractions.
通过湿筛法将从长江采集的沉积物分离成五个粒径级分（>200微米、200 - 125微米、125 - 63微米、63 - 25微米、<25微米）。测定了分级沉积物中列为美国环保署优先污染物的16种多环芳烃（PAHs）的浓度。总PAHs浓度范围为26.1至7135.9纳克/克，在不同粒径级分之间差异很大。最高的总PAHs浓度（7135.9纳克/克）与最大粒径级分（>200微米）相关，而细粉砂级分（63 - 25微米）的总PAHs浓度最低，为26.1纳克/克。尽管不同级分之间的PAHs浓度差异很大，但五个粒径级分中PAHs的组成呈现出相似的模式，以三环或更多环的PAHs为主。小于25微米的沉积物颗粒贡献了总PAHs的75%，而其占沉积物干重的38.6%。所有粒径级分中PAHs与总有机碳（TOC）之间存在显著正相关（p < 0.01），这表明TOC对沉积物中PAHs的分布很重要。此外，沉积物有机质类型和结构在不同粒径级分的PAHs分布中也起着重要作用。
