Polycyclic aromatic hydrocarbons in the Baltic Sea - Pre-industrial and industrial developments as well as current status

Abstract

We report on Baltic Sea polycyclic aromatic hydrocarbon (PAH) pressure based on the U.S. EPA PAHs in view of millennial and decadal developments utilizing data from sediment deposits and seawater. Pre-industrial PAH contents ranged from 500 to 4500 ng/g TOC. Maximum PAH contents were up to 100,000 ng/g TOC and date back to the 1960s to 1970s with maximum pollutant inputs. Contemporary sediment PAH contents with 10,000 to 35,000 ng/g TOC and seawater concentrations with about 1 to 16 ng/l show spatial variability due to different local inputs and sediment characteristics. Pre-industrial compositional change from low molecular weight to high molecular weight (HMW) PAH indicates changing sources from mostly petroleum to combustion. Application of diagnostic ratios reveals petroleum and combustion as contemporary PAH sources and that traffic emissions continuously contribute to the Baltic PAH profile. Medium to high toxicological risk to the marine community might arise from current HMW PAH contents.

Keywords: Baltic Sea; Diagnostic ratios; Polycyclic aromatic hydrocarbons; Sediment deposits.