Polycyclic aromatic hydrocarbons in remote mountain lake waters.

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Atmospheric Science

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants originating from incomplete combustion.
• Remote mountain lakes act as sensitive indicators of atmospheric pollution due to limited local sources.
• Understanding PAH sources and fate in aquatic ecosystems is crucial for environmental risk assessment.

Purpose of the Study:

• To identify and quantify polycyclic aromatic hydrocarbons (PAHs) in European mountain lake waters.
• To investigate the influence of seasonal variations (ice-free vs. ice-covered) on PAH concentrations and composition.
• To explore the relationship between PAH patterns, water temperature, and potential sources like atmospheric transport.

Main Methods:

• Water samples were collected from three remote European mountain lakes during ice-free and ice-covered periods.
• Analysis of polycyclic aromatic hydrocarbons (PAHs), including alkylated and sulfur derivatives, in both dissolved and particulate phases.
• Comparison of PAH profiles across different lakes and water phases to infer sources and transport mechanisms.

Main Results:

• Consistent PAH concentrations (700-1100 pg/l) were observed across the three studied lakes.
• Low molecular weight PAHs dominated in Lakes Redó and Gossenkölle, while high molecular weight PAHs were significant in Lake Ovre Neådalsvatn.
• Dissolved PAH concentrations showed a negative correlation with water temperature, increasing below 6-7°C, suggesting atmospheric condensation.

Conclusions:

• Remote mountain lakes receive comparable levels of polycyclic aromatic hydrocarbons (PAHs) from atmospheric deposition.
• PAH composition varies regionally, with high molecular weight compounds potentially linked to combustion and long-range transport.
• Water temperature significantly influences the partitioning and concentration of dissolved PAHs in these cold aquatic environments.