The Gulf of Finland, Archipelago Sea

Carbonate chemistry in sediment pore waters; Trace metalloid and inorganic selenium concentrations in sediment pore water; Nutrient concentrations in sediment pore waters

Sediment grabs; atomic absorption spectrometers; inductively-coupled plasma atomic emission spectroscopes

The samples were taken with gravity corer from soft sediment on board R/V Aranda on different cruises 2001-. The sediment cores were cut into 1 cm subsamples and from 0-10 in 1cm interval, 15-16, 20-21 and 25-26 cm were analysed for total metals. Freeze dried and homogenised samples were digested with aqua regia hydrofluoric acid and boric acid by microwave oven for total metal analysis. 16 elements were analysed by AAS and ICP-AES (including P). Easily available metals were analysed from 0-5 and 25-26 cm. Freeze dried sediment samples were extracted with 0,11M acetic acid for 2 hours. 11 elements were analysed by ICP-MS. Easily available extractions were made for fresh sediment samples from few stations. Sediment pore water was squeezed from the sediment through 0,45 micrometer filter with hydraulic jack. Pore water was directed to helium filled gas box and aliquot 12 ml samples were acidified with strong s.p. HNO3. Pore water samples were stored at + 4 degrees Celcius and analysed with ICP-MS. 12 elements were analysed by ICP-MS (including P). Analysing certified reference materials with samples controlled the quality of analysis. This is ongoing study.

Finnish Environment Institute
Latokartanonkaari 11
Helsinki

00790
Finland