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During the course of our studies of in-use chlorinated flame retardants, such as Dechlorane Plus® and Dechloranes 602 and 604, blubber of beluga whales from the Canadian Arctic and lake trout and whitefish from the North American Great Lakes were found to contain two novel dechlorination products of Dechlorane 602 (Dec602). The structures of these compounds were characterized by experiments performed using both gas chromatography-high resolution mass spectrometry and Fourier transform mass spectrometry with a prepared technical mixture of monohydro and dihydroDec602 derivatives. These Dec602 derivatives are analogous to the well-known monohydro and dihydro photochemical degradation products of Mirex. The ratio of the two monohydroDec602 diastereomers varied between Lake Ontario fish and those from the upper lakes, but only one isomer was found in Arctic beluga, indicating that one isomer is either more stable or more bioaccumulative. Dechlorane Plus®, Dec603, and Dec 604 were not detected in Arctic beluga, but Dec602 and its monohydroDec602 derivative were measured in approximately equal concentrations, ranging from 25 to 300 pg/g lipid. In Great Lakes fish, concentrations of the monohydroDec602 derivatives were also close to those of Dec602, ranging from 2 to 67 ng/g lipid and were greatest in Lake Ontario. This study reports on the first measurements of dechlorane-related compounds in Arctic biota and the first detection of monohydroDec602 degradation products and their accumulation in biota. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Parallel air and water samples were taken on lakes Superior, Huron, Erie and Ontario between 1996 and 2000 to determine the occurrence and levels of hexachlorocyclohexanes (HCHs), trans-chlordane (TC), cis-chlordane (CC), dieldrin (DIEL) and the metabolite heptachlor exo-epoxide (HEPX). Concentrations in the water varied greatly among the lakes, but air concentrations were similar, thus resulting fugacity ratios varied by lake and compound. The enantiomer fraction, EF=(+)/[(+)+(−)], was determined for α-HCH, TC, CC and HEPX. Enantioselective degradation of (+)α-HCH was found in water of all the lakes where the depletion was greatest for Lake Superior, which has the longest water residence time. Preferential loss of (+)TC and enrichment of (+)HEPX were found in lakes Superior and Ontario, with similar EFs in both lakes. CC was racemic in Lake Superior and showed depletion of the (+) enantiomer in Lake Ontario. Depletion of (+)α-HCH, (+)TC and enrichment of (+)HEPX was seen in all air samples. CC varied from depletion of the (+) or (−) enantiomer and was racemic in some cases. Higher concentrations of α-HCH in the air over Lake Superior were correlated with less racemic composition, providing evidence of water-to-air exchange. Fugacity ratios for the HCHs approached equilibrium conditions within a factor of 2, with slight excursions toward net volatilization or deposition, where generally higher excursions were seen for the cyclodienes. [Copyright &y& Elsevier]

Biota and surface sediments collected from Lake Ontario were analyzed for polychlorinated naphthalenes (PCNs) and non- and mono-ortho-substituted polychlorinated biphenyls (n/m-o-PCBs) to compare bioaccumulation behavior of these classes of dioxin-like chemicals in a food web from the Great Lakes. Mean ∑PCN concentrations (tri-octaCN) ranged from 14 ± 9 pg/g in plankton to 3500 ± 3200 pg/g (wet weight) in lake trout, while sediments contained from 21 to 38 ng/g (dry weight). Principal components analysis of PCN congener patterns indicated that chlorine substitution determined which congeners favored accumulation (e.g., CN-42, -52, -60, -66, -67, and -73), while others may be subject to metabolism. The bioaccumulative congeners exhibited similar trophic magnification factors (TMFs; 1.23-1.42) and biomagnification factors (BMFs; 5.5-8.6) to the n/m-o-PCBs for the trout/weighted diet relation, although BMFs for a benthic feeding relationship (slimy sculpin/Diporeia) indicated that the n/m-o-PCBs were more bioavailable through the benthic pathway. PCNs contribute significantly to the burden of dioxin-like compounds in Lake Ontario biota, contributing between 12 and 22% of total PCN + PCB TEQ in lake trout and up to 69% in benthic organisms. [ABSTRACT FROM AUTHOR]

A chlorinated compound (Chlordene Plus, CP), structurally related to Dechloranes (Dec) 602, 603, 604, and Dechlorane Plus (DP), was identified, and concentrations and spatial trends of Dec 602, 603, 604, CP, and DP in tributary sediments of the Laurentian Great Lakes are reported. The dechloranes were widely detected with their concentrations varying considerably across the Great Lakes basin. Spatial trends of Dec 602, 604, and DP in Canadian tributary sediments were similar to that of BDE 209, which suggested these flame retardant chemicals in tributaries were associated with industrial and urban areas. The highest concentrations of Dec 602, 604, and DP observed in tributaries of the Niagara River confirmed that past or ongoing manufacturing of these compounds at plants along the river were important sources to Lake Ontario. Dec 603 was detected in technical products of aldrin and dieldrin, and its spatial trend was consistent with historic pesticide usage. Similarly, CP was detected in technical products of chlordene and chlordane, and it was found in higher concentrations in sediments near urban areas, possibly related to past chlordane use in home termite control. [ABSTRACT FROM AUTHOR]

A recently discovered chlorinated flame retardant, Dechlorane Plus (DP), was reported in air and a sediment core within the North American Great Lakes region. To further reveal the fate of DP in the Great Lakes, 40 surficial sediments from Lakes Erie and Ontario and two additional cores were analyzed using newly available analytical grade DP isomer solutions. The maximum total concentration in Lake Ontario was over 60-fold higher than Lake Erie, 586 ng/g and 8.62 ng/g, respectively. Additionally, analysis of archived suspended sediments collected from the Niagara River (1980-2002) showed a declining total DP concentration of 89 ng/g to 7.0 ng/g, suggesting a possible decrease in production orthe reduction of free DP released into the environment during manufacturing. The average syn-DP fractional abundance (fsyn) in our study was less than the commercial DP composition indicating a stereoselective enrichment of anti-DP in the environment Mean fsyn profiles were uniquely similar to both Lake Ontario and the Niagara River in comparison to Lake Erie. Ouring the course of our analysis we noticed an increasing fsyn value in the calibration standard which became exacerbated as the liner got dirtier and suggested the prospect of DP degradation. Follow- up studies indicated these compounds were dechlorinated DP species produced on the injection liner. Using a clean injection liner, these degradates were also detected in sediments from the Niagara River and Lake Ontario; tentatively identified as [-Cl+H] and [-2Cl+2H] by high resolution mass spectrometry. The observed similarity of fsyn profiles between Lake Ontario and Niagara River and the detection of the degradates only in their locations, suggest to us that the river is a major source to Lake Ontario's DP burden. To our knowledge, this is the first report of DP degradates in the environment [ABSTRACT FROM AUTHOR]