Summary of Dechlorane Plus

Dechlorane Plus (DP) is a highly chlorinated flame retardant (see Figure 1). It is a substitute for Dechlorane, which was also marketed under the name Mirex as a pesticide and was banned in 1970s. Although DP has been in use for decades, it was found in the environment for the first time in IADN samples. In fact, DP was detected in samples from all six IADN sampling sites, with relatively high levels in samples from Sturgeon Point. This observation suggests that the manufacturing facility of DP, OxyChem in Niagara Falls, New York, might be the main source of DP to the Great Lakes. For more detailed results please see Dechlorane Plus, a Chlorinated Flame Retardant, in the Great Lakes.

Anti-DP	Syn-DP

Figure 1. Molecular structures of the two Dechlorane Plus stereoisomers

 

DP in Tree Bark from the Northeastern U.S

To locate the source of DP and to determine the spatial distribution of DP as a function of distance from the source, tree bark samples were collected from the northeastern United States, especially from the region between Lake Erie and Ontario. DP was detected in all of these samples. The highest concentrations of DP were found in the samples from Niagara Falls, and these concentrations decreased sharply with distance from Niagara Falls. A simple one-dimensional Gaussian diffusion model can nicely describe the distribution of DP in tree bark in this region, and this model pinpoints DP’s source in Niagara Falls (sea Figure 2).
Figure 2. Concentrations (in ng/g bark) of DP in Tree Bark as a Function of Spherical Euclidian Distance (in km) from the OxyChem Plant in Niagara Falls, New York.

Figure 2. Concentrations (in ng/g bark) of DP in Tree Bark as a Function of Spherical Euclidian Distance (in km) from the OxyChem Plant in Niagara Falls, New York.

DP in Sediment from Lake Ontario (for more details follow this link)

Because of atmospheric transport and deposition and because of direct and indirect inputs from the Niagara River, Lake Ontario is severely polluted with DP. The conclusion is based on our measurements of DP and other flame retardants in a sediment core from the central basin of Lake Ontario. These data showed that the concentration of DP in sediment increased rapidly starting in the mid-1970s and reached its peak concentration (310 ng g?1 dry weight) in the mid-1990s. We estimate that there is now ~20 tons of DP in Lake Ontario’s sediment. It is interesting to note that the concentration of DP in sediment from Lake Ontario exceeds that of all the brominated flame retardants combined, including PBDEs and TBE (see Figure 3). For more detailed results please see[q1] Dechlorane Plus and Other Flame Retardants in a Sediment Core from Lake Ontario. Figure 3. Concentrations of DP (sum of syn and anti isomers) and Other Brominated Flame Retardants in a Sediment Core from Lake Ontario as a Function of Year of Deposition.

Figure 3. Concentrations of DP (sum of syn and anti isomers) and Other Brominated Flame Retardants in a Sediment Core from Lake Ontario as a Function of Year of Deposition.