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

Abstract

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 À 1 (avg. 0.21 μg g À 1), and from 0.04 to 0.29 μg g À 1 (avg. 0.15 μg g À 1) on a dry wt. basis, respectively. Understanding the temporal evolution of nalkanes 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 socioeconomic 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.

Source-specific ecological and health risks of polycyclic aromatic hydrocarbons in the adjacent coastal area of the Yellow River Estuary, China

“…43 Specically, the reason why sediment samples collected in August had a signicantly much higher content of PAHs than other two months was possibly attributed to the geographic location. The adjacent coastal area of the YRE is highly inuenced by the riverine input of the Yellow River, one of the world's most sediment-laden rivers, 23 which may renew the surface sediment periodically to form obviously different contents of pollutants. The characterization of seawater and sediment are presented in Table 1.…”

“…The Yellow River is one of the world's most sediment-laden rivers and has witnessed an increase in PAH pollution in the Yellow River Estuary (YRE) in recent years. 23 Moreover, Shandong Province, the location of the YRE, is recognized as one of the regions with the highest emissions of PAH pollution in China. 24 This study focused on the adjacent coastal area of the YRE and collected surface seawater, surface sediment, and clams ( Ruditapes philippinarum and Mactra veneriformis ) at four sites in May, August, and October 2021.…”