Polycyclic aromatic hydrocarbons in permafrost peatlands.

Area of Science:

• Environmental Chemistry
• Geochemistry
• Organic Geochemistry

Background:

• Polycyclic Aromatic Hydrocarbons (PAHs) are persistent organic pollutants found in various environmental matrices.
• Peatlands are crucial archives for reconstructing past environmental conditions and pollutant deposition.
• Understanding PAH distribution in peat can provide insights into historical pollution sources and environmental processes.

Purpose of the Study:

• To determine the concentrations and composition of 15 individual PAHs in 93 peat cores.
• To investigate the spatial and vertical distribution of PAHs in peatlands across different geographical regions (Eastern Europe and West Siberia).
• To identify potential correlations between PAH profiles, peat types, and paleoenvironmental conditions.

Main Methods:

• High-performance liquid chromatography (HPLC) was employed for the quantitative and qualitative analysis of 15 individual PAHs.
• Peat cores were collected from 93 distinct locations.
• PAH concentrations were measured in nanograms per gram (ng/g).

Main Results:

• Total PAH concentrations ranged widely from 112 to 3673 ng/g, with a mean of 1214 ± 794 ng/g.
• Heavy, highly condensed PAHs, particularly benzo[ghi]perylene, were dominant in Eastern European peat plateaus.
• Light PAHs, such as naphthalene and phenanthrene, were more prevalent in West Siberian permafrost peatlands.

Conclusions:

• PAH composition in peat cores is non-uniform and varies significantly based on geographical location and peat type.
• The dominance of heavy PAHs in Eastern Europe and light PAHs in West Siberia suggests different pollution sources or formation pathways.
• The consistent presence of benzo[ghi]perylene throughout peat strata, including permafrost, indicates persistent anaerobic conditions necessary for its synthesis during the Holocene.