title: POPs and organic polysufides in sediments of Lake Ladoga.
abstract: The study included one station close to a pollution source (depth 59 m) and another far from polluted areas (depth 40 m). Samples were analysed for organic chlorine, bromine and sulfur compounds. Samples taken with a corer were sliced to the layers of 0-1, 1-4, 4-7 cm etc. down to the depth of 34 cm. The dating was made with two independent methods, the 210Po method and with the soot particle counting method. The analyses were made with a multiresidue method. Gas chromatography was connected to low resolution mass spectrometry (LRMS) or to high resolution mass spectrometry (HRMS). A different extraction was applied to screen the possible occurrence of polysulfides. Typical chlorophenol and chlorohydrocarbon traces from chlorobleaching of pulp were non-detectable. Also PCDDs, PCDFs, PCBs and various organochloride pesticides, fire retardant residues PBDEs, PBDDs and PBDFs and polychlorinated phenyl salicylates were not detected. Instead, methylated dibenzothiophenes Me-DBTs and Di-Me-DBTs, typical traces of oil based defoamers used in e.g. paper mills were found in the surface layers of the polluted site. Polysulfides were analyzed from layers representing years 1955-1970 from the polluted site. The structures of five congeners were according to GC/MS dimethyl trisulfide, 1,2,3,4-tetrathiepane, pentathiane, 1,2,3,4-tetrathiane and 1,2,4,5-tetrathiepane. Many of the analyzed pollutants have not been reported earlier from Lake Ladoga. The only positive observations were from oil-based defoamers used in paper mills, and from polysulfides, which are either of natural origin or indicate a discharge in the 1950s and 1960s. Owing to the large spreadout and dilution, the concentrations are low even at moderate distances from the pollution centers.
authors.affiliation: Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland. jsarkka@cc.jyu.fi
authors.forename: Jukka
authors.initials: J
authors.lastname: Särkkä
authors.forename: Juhani
authors.initials: J
authors.lastname: Hynynen
authors.forename: Keijo
authors.initials: K
authors.lastname: Mäntykoski
authors.forename: Sirpa
authors.initials: S
authors.lastname: Herve
authors.forename: Mirja
authors.initials: M
authors.lastname: Lahtiperä
authors.forename: Jaakko
authors.initials: J
authors.lastname: Paasivirta
mesh_terms: D002733:Chlorophenols / Q000032:analysis; D005387:Finland; D005618:Fresh Water / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000032:analysis; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis*; D013440:Sulfides / Q000032:analysis*; D013876:Thiophenes / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002733:Chlorophenols; D006842:Hydrocarbons, Brominated; D006843:Hydrocarbons, Chlorinated; D009930:Organic Chemicals; D013440:Sulfides; D013876:Thiophenes; D014874:Water Pollutants, Chemical; C016366:dibenzothiophene