Compounds Structurally Related to Dechlorane Plus in Sediment and Biota from Lake Ontario (Canada)

Abstract

The historical occurrence of Dechlorane Plus (DP) and detection of novel compounds structurally related to DP is described in a dated Lake Ontario sediment core. Our core was collected near the mouth of the Niagara River, which is known to be a major source of DP to the lake. Maximum DP concentrations (920 ng g(-1), dry weight) were observed between 1976 and 1980, the highest reported to date. Following that time, we observed a dramatic decrease in DP concentration which coincided with the enactment of United States federal and state laws to mitigate free release of chemicals into the Niagara River and installation of an industrial wastewater treatment facility. During the course of our research, four new substances structurally related to DP were also identified. These compounds were thought to arise from the Diels-Alder reactions resulting from impurities present in 1,5-cyclooctadiene, a feedstock used in production of DP. To confirm our hypothesis, Diels-Alder reactions were performed on the individual impurities. Using different stationary-phase capillary gas chromatography columns and high-resolution mass spectrometry, we were able to positively identify some of these novel compounds in the core. Interestingly, we also were able to identify a monoadduct compound, formed by addition of 1 mol of hexachlorocyclopentadiene to 2 mol of 1,3-cyclooctadiene, in lake trout. The concentration of this monoadduct was approximately 2 orders of magnitude greater than that of DP, suggesting that it is more bioaccumulative.

Sources and environmental behaviors of Dechlorane Plus and related compounds — A review

“…In some cases, sulfuric acid or acidic silica gel was alternatively added to the extract to remove lipid in biota prior to column cleanup (Ismail et al, 2009;Qiu and Hites, 2008;Ren et al, 2008). However, if DP mono adduct (DPMA), arising from the Diels-Alder reactions of impurities present in feedstock (1,3-or 1,5-cyclooctadiene) (Sverko et al, 2010b), would be analyzed along with DP, nondestructive methods such as GPC were strongly suggested for sample cleanup because acid treatment will degrade DPMA by attacking at its nonhalogenated double bond (Feo et al, 2012;Sverko et al, 2010b).…”

“…In EI mode, fragmentation process was much more extensive and therefore the two most abundant ions of a fragment cluster (m/z: 271.8102/273.8072) were selected for DP monitoring when using HRMS (Feo et al, 2012;Shen et al, 2011a,b). EI mode was not recommended since an intense ion at m/z 270 (C 5 Cl 6 + ) will be formed in retro-Diels-Alder fragmentation, which may make the intensity of molecular ion low or even absent (Feo et al, 2012;Sverko et al, 2010b). Even so, there were many successful measurements conducted by monitoring the 271.8102/273.8072 ions using EI in HRMS (Brasseur et al, 2014;Shen et al, 2010Shen et al, , 2011aShen et al, , 2011b.…”

“…This lack of clear temporal trend suggested that the inputs of DP into the surrounding environment have not distinctly changed during the 2000s (Salamova and Hites, 2011). However, at a longer time scale, DP levels generally declined in sediment and biota collected from the Niagara River and Lake Ontario since the 1980s (Hoh, et al, 2006;Shen et al, 2010Shen et al, , 2011aSverko et al, 2008Sverko et al, , 2010b. Some studies indicated a period of increasing levels since the 1970s in sediment from central Lake Ontario, and the levels peaked during 1980-1990s (Qiu et al, 2007;Sverko et al, 2010b;Yang et al, 2011).…”

Particle-bound Dechlorane Plus and polybrominated diphenyl ethers in ambient air around Shanghai, China

“…Three typical DP emission sources have been reported in the published literature: DP manufacturing plant (Hoh et al, 2006;Qiu et al, 2007;Sverko et al, 2010;Tomy et al, 2007), DP-containing ewaste recycling activities (Ren et al, 2008(Ren et al, , 2009) and the use of DPcontaining products (Zhu et al, 2007). Furthermore, DP could affect source-nearby areas via air transportation (Qiu et al, 2007).…”

“…It was only recently detected in the environment (Hoh et al, 2006) even though it has been produced for almost fifty years. Most published research on DP has focused on the Great Lakes area (Hoh et al, 2006;Qiu et al, 2007;Qiu and Hites, 2008;Sverko et al, 2008Sverko et al, , 2010Tomy et al, 2007), which results suggest that DP is bio-available and bio-accumulative (Gauthier and Letcher, 2009;Ismail et al, 2009). As for Asia, Qiu and Hites (2008) analyzed the tree barks from China and Korea and suggested that there might be Asia-specific sources of DP to the environment.…”