Spectroscopic Characterization of 7b,8c,9c-Trichlorocamphene-2-one Formed from Toxaphene Components in an Anaerobic Soil

Abstract

A cyclic ketone, formed from the toxaphene components Toxicant A (Parlar No. 42) and Toxicant B (Parlar No. 32) in a flooded loamy silt in laboratory experiments, has been isolated, and its structure has been characterized. The product has been shown to have a camphenone skeleton, possibly formed via a Wagner−Meerwein rearrangement. The structure has been identified as 7b,8c,9c-trichlorocamphene-2-one. This is the first time that an oxygen-containing product as conversion product of a toxaphene component has been isolated. Comparison with the behavior of single toxaphene components in autoclaved soil points out that the 7b,8c,9c-trichlorocamphene-2-one is the result of biotransformation. Keywords: Toxaphene degradation; chlorinated camphenone; biotransformation

Environmental occurrence, analysis, and toxicology of toxaphene compounds.

“…Fingerling et al. (14) state that toxaphene consists of at least [180][181][182][183][184][185][186][187][188][189][190] components mostly with the formula C 10 H 18-n Cl n or C 10 H 16-n Cl n where n is 6-10. Buser et al (15) report that polychlorobornanes (C 10 H 18-n Cl n where n = 5-12) are formed as the main components in a Wagner-Meerwin type rearrangement reaction.…”

Prominent chlorobornane residues in estuarine sediments contaminated with toxaphene

“…More recently, Stern et al [4] reported the predominance in freshwater sediments of 2‐ exo ,3‐ endo ,6‐ exo ,8,9,10‐hexachlorobornane (B6‐923 or Hx‐Sed) and 2‐ endo ,3‐ exo ,5‐ endo ,6‐ exo ,8,9,10‐heptachlorobornane (B7‐1001 or Hp‐Sed), compounds that are now widely believed to be reductive dechlorination metabolites of major components of technical toxaphene (CTTs). These findings were corroborated in laboratory experiments, where the formation of Cl 6 and Cl 3 metabolites of pure, spiked toxaphene components was observed in soils maintained under anaerobic conditions [5,6]. However, to date, no Cl 5 or Cl 4 metabolites have been reported in laboratory or field studies.…”

“…The reductive dechlorination of CHBs with geminal chlorines at C‐2 has been shown to be relatively rapid under reducing conditions [5,6,17] or in the presence of nonbiological stimuli such as ultraviolet light [18]. The two major dead‐end metabolites, B6‐923 and B7‐1001, are void of dichlorosubstituents on any one carbon atom (Fig.…”

“…The reductive dechlorination of CHBs with geminal chlorines at C-2 has been shown to be relatively rapid under reducing conditions [5,6,17] or in the presence of nonbiological 260 310 17 18 33 7.8 2 5,300 330 370 17 19 30 12 3 2,500 170 180 19 12 18 14 4 7,300 250 260 41 58 150 32 5 3,800 220 260 14 17 30 5.6 a Ͻϭ indicates detected but less than method detection limit. stimuli such as ultraviolet light [18].…”

“…These findings were corroborated in laboratory experiments, where the formation of * To whom correspondence may be addressed (kam@skio.peachnet.edu). Cl 6 and Cl 3 metabolites of pure, spiked toxaphene components was observed in soils maintained under anaerobic conditions [5,6]. However, to date, no Cl 5 or Cl 4 metabolites have been reported in laboratory or field studies.…”