Mercury in chemical fractions of recent pelagic sediments of the sea of Japan.
The distribution of mercury (Hg) in chemical fractions (H2O, 0.05 M Na2-EDTA pH 3, 1 M HCl, humic and fulvic acids, and non-hydrolysing residue) of recent pelagic sediment cores of the Sea of Japan (East Sea) was studied. Total Hg content in the sediments was rather low: 83 +/- 30 (21-173) etag g(-1), indicating the absence of substantial specific sources of the element in the deep part of the sea. Hg content within the sediment core varied by a factor of 1.3-1.8, showing peaks that coincide with the near-surface and buried sediment slices of light brown and brown "oxidized" colours and evidencing Hg redox-sensitive diagenetic redistribution. Hg exerted its maximum mobility in the near-surface sediment strata as a component of water-soluble organic matter. Despite the predominance of fulvic acids in extracted humus fractions, humic acids were a much more efficient concentrator for Hg (0-79 vs. 188-233 microg Hg g(-1) C(org), respectively). Nevertheless, the most refractory non-hydrolyzing residue (humin) fraction contained the principal Hg pool in the sediments. Hg content in all the extracted fractions decreased with core depth, thus indicating Hg immobilization as a principal tendency in Hg fate during post-depositional diagenesis.
Kot
Fyodor S
FS
Laboratory of Biogeochemistry, Institute of Water and Ecological Problems, 65 Kim Yu Chen St., Khabarovsk, 680000, Russian Federation. kott@ivep.as.khb.ru
D001578:Benzopyrans / Q000737:chemistry; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis; D007564:Japan; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D009792:Oceans and Seas; D014874:Water Pollutants, Chemical / Q000032:analysis*
D001578:Benzopyrans; D006812:Humic Substances; D014874:Water Pollutants, Chemical; D008628:Mercury; C005023:fulvic acid