DDD Isomers Research Articles

Volatility of DDT Residues in Soil as Affected by Flooding and Organic Matter Applications

AbstractIn a field experiment, flooding with and without organic matter additions was evaluated as a means of preferentially degrading residual DDT and thereby changing the ratio of the various isomers and metabolites volatilizing from the soil surface. Flooding for a 7‐week period, either with or without manure or alfalfa (Medicago sativa L.) meal applications, effectively degraded DDT isomers, primarily to the respective DDD isomers, but had little effect on DDE isomers. Both flooding and organic matter decreased the volatility even when soil concentrations were not affected, apparently because of increased adsorption of the compounds by added organic matter or by organic matter in the soil altered by flooding. The data indicate that minor changes in vapor concentration ratios were accomplished by flooding and organic matter additions, but regardless of treatment, the major constituent evaporating from the surface was p,p′‐DDE. To accomplish significant changes in volatilization patterns, it will be necessary to use such management practices before a major part of the DDT has been degraded to DDE. However, flooding and organic matter treatments will ultimately decrease the total quantity of DDE volatilizing from residual DDT in soils over long‐time periods because of their effectiveness in degrading DDT to DDD instead of DDE.

The ion kinetic energy spectra of some chlorinated insecticides

AbstractThe ion kinetic energy (IKE) spectra of the p,p′ and o,p′ DDT, DDD and DDE isomers have been examined. The results indicated that the decomposing [M‐CCl3] ions (b) (m/e 235) for the p,p′ and o,p′ DDT isomers were not energetically similar, suggesting retention of the positional identity of the aromatic chlorine substituents. Similar results were obtained for the [M – CHCl2] ions (b) for the p,p′ and o,p′ DDD isomers. The IKE spectra of p,p′ and o,p′ DDE were indistinguishable, indicating loss of substituent identity of the aromatic chlorine group. The mechanistic and analytical consequences of these data are discussed. The IKE spectra of the four hexachlorocyclohexane isomers (V to VIII) are different and these spectra are obviously useful in the analysis and characterization of these structurally similar compounds. The differences in their reactivity must in some part be due to their different stereochemical orientations of the chlorine substituents.

The effect of isomers of DDD on the ACTH-induced steroid output, histology and ultrastructure of the dog adrenal cortex

The effect of 3 geometric isomers of DDD on ACTH-induced steroid production, histology, and ultrastructure of the dog adrenal cortex were examined. When administered iv, equal doses of all 3 compounds eventually inhibited ACTH-induced steroid production. The order of onset of inhibition was m, p′-DDD > o, p′-DDD > p, p′-DDD with the inhibition reaching 50% of control values at 27 min, 87 min and between 4–18 hr, respectively. Histologic examination of the various zones of the adrenal cortex showed minimal effects, from any of the isomers, on the zona glomerulosa at times when the internal structure and spacial arrangement of the cells of the zona fasciculata and reticularis were markedly disrupted. Electron micrographs revealed that these DDD isomers exhibited very minimal effects on the mitochondria of the zona glomerulosa. On the other hand, the mitochondria of the zonas fasciculata-reticularis underwent progressive swelling, dissolution, and eventual rupture following DDD treatment. The order of onset of histologic and ultrastructural effects was m, p′-DDD > o, p′-DDD > p, p′-DDD. However, for each isomer the ultrastructural damage was detected prior to the observation of histologic lesions. Thus, there was a marked temporal correlation between the percentage inhibition of ACTH-induced steroid production, the disruption of normal cellular structure and arrangement in the innermost zones of the adrenal cortex, and the severity of the DDD-induced mitochondria damage in the cells of the zonas fasciculata-reticularis by each of the 3 isomers of DDD.

Different ratios of the ldd and ddd diastereoisomers of phytanic acid in patients with Refsum's disease

1. 1. Both the ldd and ddd diastereoisomers of phytanic acid accumulate in patients with Refsum's disease.Considerable differences occur in the ldd/ ddd ratios of the phytanic acid in these patients, probably depending on differences in the diet. 2. 2. The limited degradation of phytanic acid which takes place in patients with Refsum's disease removes the ldd and ddd isomers at approximately the same rate. 3. 3. Experiments with polecats also indicate that the rapid degradation of phytanic acid which takes place in normal mammals removes the ldd and ddd isomers at approximately the same rate. 4. 4. The distribution of the ldd and ddd isomers of phytanic acid among the various lipid fractions in serum indicates that the ldd and ddd isomers have different kinetics for several acyl activating systems and/or acyltransferases. 5. 5. Administration of phytol to the polecat gives rise to an accumulation of phytanic acid with a preponderance of the ldd isomer.