Dechlorane Plus Levels in Sediment of the Lower Great Lakes

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.