Identification
and Occurrence of Analogues
of Dechlorane 604 in
Lake Ontario Sediment and their Accumulation in Fish
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Abstract
The
dechlorane family of flame retardants, which includes Mirex
(also known as Dechlorane), Dechlorane Plus (DP), and Dechloranes
(Dec) 602, 603, and 604, were manufactured at a facility along the
Niagara River, upstream of Lake Ontario. Some of these compounds remain
in use. In a previous study, we found Mirex and Dec602 to have greater
bioaccumulation potentials than Dec604 and DP based on calculated
biota-sediment accumulation factors (BSAFs). In this study, analogues
of Dec604, containing fewer bromines and mixed substitutions of bromine
and chlorine, were identified in Lake Ontario sediment and fish using
high and ultrahigh resolution mass spectrometric techniques. The tribromo-Dec604
(Br<sub>3</sub>Dec604) analogue, known as Dechlorane 604 Component
B (Dec604 CB), was present in lake trout and whitefish at concentrations
of 10β60 ng/g lipid weight, approximately 50β200 times
greater than concentrations measured for Dec604. In addition, BrDec604
and Br<sub>2</sub>Dec604 analogues, and mixed Br<sub>2</sub>Cl<sub>2</sub>Dec604, Br<sub>3</sub>ClDec604, Br<sub>2</sub>ClDec604, and
BrCl<sub>2</sub>Dec604 analogues were also present. We have shown
that solutions of Dec604 and Dec604 CB exposed to UV-light undergo
photodebromination and give rise to the analogues found in sediment
and fish. Dec604 CB and other lesser halogenated analogues of Dec604
show greater bioaccumulation potentials than Dec604, Dec602 and DP,
based on BSAFs, which highlight the need to consider likely impurities
and degradation products in the assessment of persistent, bioaccumulative,
and toxic compounds