The Gulf of Finland, The Bothnian Bay

Inorganic chemical composition of sediment or rocks

Unconsolidated sediment corers

The data set consists of sediment analyses carried out by the Finnish Institute of Marine Research from onboard R/V Aranda in 1993-1994. Sediment samples were collected using gravity corers and sliced into 1 cm subsamples. For EOX analysis, the samples were extracted with cyclohexane-isopropanol solution, washed with nitrate and finally concentrated and combusted in Euroglas 2000 microcoulometric analyser. The AOX analysis was based on adsorption of organic compounds to activated carbon and burning of the sediment and the activated carbon. Standard deviation of replicate measurements was calculated. Vertical EOX distributions have been studied in 1994, otherwise only surficial sediments have been analysed. In the studies carried out in 1993, AOX concentrations were analysed from the sediment surface also in the Gulf of Finland. The areas in the Gulf of Finland include the Eastern Gulf of Finland area, the open sea area and coastal areas near the cities of St. Petersburg, Tallinn, Kotka, Vyborg and Sovetskiy. The results give a comprehensive picture of the coverage of total organohalogens in Gulf of Finland sediments, both near paper and pulp factories and in the open sea area. The vertical distributions observed near the point sources reveal trends in the pollution history. Results from the ICES-HELCOM sediment baseline study cover some areas in the Bothnian Bay. Most of the data from open sea can be used for estimating natural background EOX levels.

Finnish Environment Institute
Latokartanonkaari 11
Helsinki

00790
Finland