Sources and historical sedimentary record: Temporal variability of n-alkane and PAHs from the Yellow River Estuary, China.

The composition and distribution of n -alkanes and polycyclic aromatic hydrocarbons (PAHs) in suspended particulate matter (SPM) from the Yellow River and a sedimentary core from the Yellow River Estuary, China, were measured in order to determine environmental changes in the Yellow River Estuary on a regional scale. The concentration of n -alkane in SPM increased along the upper-middle-lower reaches of the Yellow River. The total concentrations of n -alkanes and PAHs in the core ranged from 0.04 to 0.86 μg g−1 (avg. 0.21 μg g−1), and from 0.04 to 0.29 μg g−1 (avg. 0.15 μg g−1) on a dry wt. basis, respectively. Understanding the temporal evolution of n -alkanes provide information on terrigenous versus aquatic productivity, oil exploration at the Shengli Oilfield, and channel diversion in the Yellow River. n -Alkanes in SPM were mainly derived from mixed sources, with terrigenous inputs dominating. PAHs in the sediment core were predominantly derived from coal and biomass combustion. The variation in PAHs levels throughout the core determines changes in energy use and socio-economic development. The temporal variability in n -alkane and PAHs and their molecular diagnostic ratios revealed a trend of regional environmental change and the role of anthropogenic activity in that environmental change. • T-ALK in SPM increased along upper-middle-lower reaches of the Yellow River. • Historical input of n -alkane and PAHs were consistent with anthropogenic activity. • Diversion of the Yellow River may cause some change of n -alkane and PAHs source. • PAHs are a sensitive tracer for anthropogenic activity. [ABSTRACT FROM AUTHOR]