Polycyclic aromatic hydrocarbons in the surface sediments from Yellow River, China

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Riverine Sediment Analysis

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants often found in aquatic sediments.
• Industrial and municipal wastewater are significant sources of PAH contamination in rivers.

Purpose of the Study:

• To determine the concentrations and sources of 16 priority PAHs in Lanzhou Reach of the Yellow River.
• To assess the potential ecological risk of PAHs in the studied sediments.

Main Methods:

• Collection of 14 surface sediment samples from the Lanzhou Reach.
• Analysis of 16 priority PAHs using gas chromatography-mass spectrometry (GC-MS).
• Calculation of molecular indices and principal component analysis (PCA) for source identification.

Main Results:

• Total PAH concentrations ranged from 464 to 2621 ng/g dry weight, with highest levels downstream of Lanzhou City.
• PAH contamination originated from both pyrolytic and petrogenic sources, indicating a mixed input.
• Sediment organic carbon content correlated significantly with total PAH concentrations (r²=0.57).

Conclusions:

• Wastewater discharge from Lanzhou Oil Refinery, Lanzhou Chemical Industry Company, and municipal sewage contributed to PAH contamination.
• While most sites had PAH levels below critical thresholds, some showed potential for adverse biological effects.
• Sediments in all sites may have potential biological impact, but are unlikely to be impaired.