Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Pore Water and Sediment of a Small Aquatic Ecosystem

Abstract

Abstract The concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured both in pore water and solid sediment isolated from the Teufelsweiher pond, a small aquatic ecosystem in Upper Bavaria (Germany) from 1992 to 1994. All 16 EPA priority compounds were present with mean total concentrations from 501 to 663 ng/1 in the pore water and 976–1600 μg/kg (dry weight) in the solid sediment. Fluoranthene and pyrene were the dominant compounds and accounted for 21–28% of the total PAHs, the ratios of fluoranthene/pyrene and phenanthrene/anthracene ranging from 1.61–2.86 and 0.86–1.57, respectively. These results suggest that the main sources of PAHs are incomplete combustion processes of fossil fuel; the compounds are then transported into the Teufelsweiher by deposition and runoff. The distribution of PAH concentrations exhibit a pronounced dependence on both particle size and organic matter content of the sediment: two fractions (< 6.3 μm and 63–200 μm), containing higher contents of organic matter, trapped more PAHs compared with other fractions. The dissolved organic carbon (DOC) in the pore water is mostly responsible for lower KOC' in situ measured compared with the estimated KOC. The spatial and temporal variations of PAH concentrations are also discussed.