The extent of bioaccumulation of the syn- and anti-isomers of Dechlorane Plus (DP) is assessed in archived food web samples from Lake Winnipeg and Lake Ontario. Concentrations of the isomers were determined using purified analytical solutions of individual isomers as opposed to the technical mixture. The syn-isomer was consistently detected in all samples from both lakes; the anti-isomer was detected in all Lake Ontario samples, but only 45% of the samples from Lake Winnipeg. The pattern of bioaccumulation was different for the isomers in Lake Winnipeg. The anti-isomer was dominant in higher trophic level (TL) organisms like walleye [arithmetic mean +/- 1 x standard error: 730 +/- 120 pg/g, lipid weight (1w)] and goldeye (760 +/- 170 pg/g, Iw) while the syn-isomer dominated the lower TL organisms like zooplankton (550 +/- 40 pg/g, Iw) and mussels (430 +/- 140 pg/g, Iw). In Lake Ontario, the extent of bioaccumulation of the isomers and concentrations was greatest in the lower TL benthic organism, Diporeia (syn, 1307 +/- 554; and anti, 3108 +/- 898 pg/g Iw) and also high in zooplankton (syn, 719; and anti, 1332 pg/g Iw). This suggests that the isomers are bioavailable in sediment and that, despite their molecular size, diffusion from the water column into zooplankton can occur. Differences in the mean fractional abundance of the anti-isomer (mean fanti = mean concentration of the anti-isomer divided by sum of mean syn- and anti-concentrations) were pronounced in sediments between lakes (Lake Winnipeg mean fanti = 0.610, Lake Ontario mean fanti = 0.860) and the extent of enrichment (anti-) and depletion (syn-) of the isomers were more marked in Lake Winnipeg biota. There were also differences in the biomagnification potentials, as measured bythe trophic magnification factor (TMF), between the isomers in the Lake Winnipeg food web; no statistically significant TMFs for either isomer were found for the

Dechlorane Plus (DP) is a high production volume, chlorinated flame retardant. Despite its long production history, it was only recently found in the environment. The first "sightings" of DP were in the North American Great Lakes, but subsequent work has indicated that DP is a global contaminant. For example, DP has recently been detected along a pole-to-pole transect of the Atlantic Ocean. Although it was initially thought that DP was produced only in North America, another DP production plant has recently been identified in China. During the course of characterizing DP in the environment, other "DP-like" compounds were identified. These DP analogs, some created from impurities contained in the starting materials during DP's synthesis, have also been detected globally. Screening-level modeling data are in general agreement with available environmental measurements, suggesting that DP and it analogs may be persistent, bioaccumulative, and subject to long-range transport and that these chemicals may be candidates for Annex D evaluation under the United Nations Stockholm Convention on Persistent Organic Pollutants. However, more research is required to better quantify the emissions, exposures, and toxicological effects of DP and its analogs in the environment. In particular, there is a need to obtain more monitoring, bioaccumulation, degradation rate, and toxicity information.

No abstract

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 (f(syn)) in our study was less than the commercial DP composition indicating a stereoselective enrichment of anti-DP in the environment Mean fyn profiles were uniquely similar to both Lake Ontario and the Niagara River in comparison to Lake Erie. During the course of our analysis we noticed an increasing f(syn) value in the calibration standard which became exacerbated as the liner got dirtier and suggested the prospect of DP degradation. Followup 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 f(syn) 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.