Systematic Studies on the Breakdown of p,p'-DDT in Tobacco Smokes

Abstract

Recently there has been much controversy concerning the use of DOT as a pesticide. This has resulted in partial or total ban on it in several countries. In this country DOT is being phased out over a period of two years (1.). In 1.968 DOT was removed from recommended compounds for tobacco (3).. lnspite of the removal of DOT as a pesticide for tobacco our studies are important for two reasons: First, tobacco leaf is cured and mellowed before .its use in the manufacture of cigarettes. This usually takes about two or three years and causes the possibility of carryover of DOT on cigarettes for several years. Second, the studies throw light on the mechanisms of the reactions involved in the degradation of pesticides in tobacco smokes. This paper is divided into two sections: Section l. deals with the isolation and identification of the degradation products from the pyrolysis of p,p'-DDT in a nitrogen atmosphere. Section 2 deals with the pyrolytic degradation of p,p'-DDT intimately mixed with tobacco. SJ:CTION 1 Pyrolysis of p,p'•DDT In a Nitrogen Atmosphere Very little work has been reported on the pyrolysis of DOT. Cavenah and ]ohns (7) have studied pyrolysis of DOT, but this was in conjunction with their method of identifying DOT by its "pyrolysis spectra". Recently, Mosier, Guenzi, and Miller (1.5) have proposed a free radical mechanism for photodecomposition of DOT. Some of their mechanisms are similar to those reported herein although reaction conditions were very different. • Presented as two papers entitled: "Isolation and Identification of the Degradation Products from the Pyrolysis of p,p'-DDT •in a Nitrogen .Atmosphere" and "Degradation of p,p'-DDT in Tobacco Smokes" before the 23rd Tobacco Chemists' Research Conference at Philadelphia, October 1969. Detailed description of the methods to be published at a later da.te.

Glutathione S-Transferase Polymorphisms and the Synergy of Alcohol and Tobacco in Oral, Pharyngeal, and Laryngeal Carcinoma

“…The u class of glutathione transferases has been associated with bioactivation and transformation of halogenated compounds, such as dichloromethane and dihaloethanes, to mutagenic intermediates (17,50). By-products of tobacco smoke include methyl chloride, which is a substrate of GSTT1 detected at appreciable levels in cigarette smoke (16). Methyl chloride undergoes a biotransformation similar to that of dichloromethane (49) and could contribute to any protection from cancer proffered by the absence of the GSTT1 alleles.…”

“…The GSTs are composed of four major groups: GSTA (a), GSTT1 (u), GSTM1 (A), and GSTP1 (k). The u class of glutathione transferases is also well known to activate haloalkanes (13), such as those found in the chlorination by-products in treated drinking water (14,15), and methyl chloride, which is found in tobacco smoke (16). GST expression varies among individuals, and this variation is tissue and gender specific (17).…”

Methyl chloride and the U.S. cigarette

“…Previous studies have looked at the possible origin of CH 3 Cl from pesticide-treated tobacco (Chopra & Sherman, 1972). However, the use of chlorinated pesticides on U.S. tobacco was prohibited in 1969.…”

“…Since then, several studies have reported on its levels in cigarette smoke (Chopra & Sherman, 1972;Hasanen, Manninen, Himberg, & Vaatainen, 1990). In most experiments, cigarette smoking machines are used to sample the cigarette in a manner that is consistent with actual human smoking.…”

DISTRIBUTION OF DDT-14C IN NICOTIANA TABACUM

“…Information relating the uptake of DDT to its distribution within the plant was lacking and it was essential to establish to what extent and where the pesticide accumulates. The presence of various degradation products of DDT in tobacco (Chopra et al 1970), their'possible association with health hazards, and the requirements for reduced total DDT levels in export tobacco (Anonymous 1966;Guthrie 1972) require continued studies of the presence of DDT in tobacco. This is a report on the distribution of DDT-*C (phenyl-rinS') [403][404][405][406][407] (Apr.…”