Analysis and Characterization of Polychlorinated Hydroxybornanes as Metabolites of Toxaphene Using a Polar Bear Model

Abstract

Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) deactivated and (iii) activated silica gel. Hence, up to 320 and 4350 μg/kg lipid weight of octa- and nonachlorinated CTTs were detected in four liver samples and adipose tissue of polar bears, respectively. Furthermore, the presence of one hexachlorinated OH-CTT isomer could be verified in the samples, which was about 1% of the octachlorinated CTTs determined in the liver samples.

Nontargeted LC/ESI-HRMS Detection of Polyhalogenated Compounds in Marine Mammals Stranded on French Atlantic Coasts

“…This substance polychlorinated hydroxybornanes, was recently detected in fish. 58,61 Interestingly, as well, 10 series represented compounds with an even number of carbons while six (4, 5, 7, 8, 11, and 13) had odd numbers of carbon. Odd numbers of carbons are rather unusual and uncommon for anthropogenic POPs.…”

Evidence for cometabolic transformation of weathered toxaphene under aerobic conditions using camphor as a co‐substrate

“…2001) and the occurrence of hydroxylated metabolite of toxaphene in the liver samples of polar bears were recently described (Reger et al . 2017). Yet, we could not detect any OH‐CTTs using an established protocol (Reger et al .…”

“…Yet, we could not detect any OH‐CTTs using an established protocol (Reger et al . 2017). These results rise the intriguing question about the role of camphor in the degradation of toxaphene.…”

“…However, advances in these two aspects were recently achieved (Kapp and Vetter 2011) allowing to identify for the first time hydroxylated metabolite of toxaphene in the liver samples of polar bears (Reger et al . 2017). Nevertheless, it is not clear if these metabolites had been formed in these bears or were assimilated from the environment.…”

Countercurrent separation assisted identification of two mammalian steroid hormones in Vitex negundo

“…CCS x LC–MS has been used in evaluation of bioactive secondary metabolites [23–28]. CCS x LC–MS has also been applied in determination of Alternaria mycotoxins in wine [29] and toxaphene metabolites in polar bear adipose tissue [30]. …”