摘要
Suspended particle samples from the Yellow River estuary were sorted into five grain size fractions to explore the effect of grain size distribution on organic matter content and composition. The n-alkanes and PAHs were determined for each size fraction. PAHs and n-alkanes were more abundant in the finer fractions and the loading decreases steadily with increasing of grain size. However, the total n-alkanes or PAHs normalized to organic C were lower in the smaller size fractions than those in the larger size fractions, suggesting n-alkanes or PAHs may be diluted by the addition of organic matter or gradually decreased by degradation in the smaller size fractions. The particulate n-alkanes in the Yellow River estuary consist of a mixture of compounds from terrigenous and riverine biogenic n-alkanes and more biogenic n-alkanes accumulate in finer particles. Particulate PAHs are related to combustion/pyrolysis processes of coal/wood, and the relative contribution of petrogenic PAHs increase with increasing grain size. The total particulate n-alkane and PAH discharges passing the Lijin Station are about 3.94 t d(-1) and 0.52 t d(-1), respectively. Fine particles (<32 mu m) Play a significant role in organic matter transfer.