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

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.

TBT and its metabolites in sediments: Survey at a German coastal site and the central Baltic Sea.

Since the 1950s the organotin compound tributyltin (TBT) was intensively used in antifouling paints for marine vessels and it became of concern for the marine environment. Herein, we report on a study from 2015 on TBT and its metabolites monobutyltin (MBT) and dibutyltin (DBT) in sediments from the central Baltic Sea and a Baltic Sea coastal site with strong harbor activities (Warnemünde). Sublayers from a sediment core from the Arkona Basin were analyzed to investigate the long term organotin pressure for the Baltic Sea. For the central Baltic Sea total organotin (MBT+DBT+TBT) ranged from 100 to 500ng/g TOC with distinct areas of high organotin content probably due to historical inputs. For the coastal site total organotin ranged from 10,000 to 60,000ng/g TOC. MBT and DBT were the predominant organotin species detected. Overall, the data obtained indicate the progress of TBT degradation at the investigated sites.