The Polytron, a high specific intensity ultrasonic generator, was used to extract insecticide residues from various soils. This system was compared with a second ultrasonic source and with Soxhlet, roller, and blender extraction procedures. The solvent of choice was acetone. Soil moisture, type, and or-ganic matter content were not critical factors in affecting quantitative recovery. Extraction for only 30 sec gave generally better recovery values than did other methods, including 8 hr of Soxhlet extraction.

Abstract-Degradation of the pesticide 3-chloro-p-toluidine hydrochloride (CPTH) occurred in a loam soil when applied at concentrations of 3.5 and 35 g/g. The compound degraded according to pseudo-first-order kinetics, with a calculated rate constant of 2.74 ϫ 10 Ϫ2 h Ϫ1 , at a soil temperature of 22ЊC; this rate constant yielded a half-life of 25 h. The loss of radiolabeled CPTH from soil was suggested to be controlled by both irreversible binding to the soil colloids and microbial transformation. Mineralization of the radiolabeled CPTH was interpreted as involving two zero-order kinetic rates; an initial rate of carbon dioxide release was estimated to be 0.33% d Ϫ1 (half-life of 152 d), followed by a slower rate of 0.07% d Ϫ1 , which resulted in a half-life of 718 d. Approximately 13% of the radiolabeled CPTH that was applied to soil at 3.5 g/g was mineralized to [14 C] carbon dioxide during the 99-d incubation period. A primary metabolite was identified as N-acetyl-3-chloro-p-toluidine (ACPTH); this metabolite reached a maximum concentration at the 1-d sampling period, and degraded with a pseudo-first-order rate constant of 2.67 ϫ 10 Ϫ2 h Ϫ1 ; the half-life for ACPTH was calculated to be 26 h. When CPTH was applied to soil at 35 g/g, the compound was also mineralized in soil by a similar metabolic pathway to that observed at the lower concentration. However, the rate of mineralization was slower, which suggests that elevated soil concentrations of CPTH may affect the viability of certain microorganisms.

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Strychnine alkaloid was demonstrated to sorb strongly to several western soils that varied in organic matter and ranged in texture from a loamy sand to a sandy clay loam. Freundlich sorption coefficients (K) for the test soils varied from 40 to 169. A direct relationship was observed between strychnine sorption and cation exchange capacity but not between sorption and organic matter content. Strychnine sorption was only partially reversible (12-44%). Degradation of 10 µg/g strychnine in sandy loam and sandy clay loam soils occurred in three distinct phases, which included a lag phase, a rapid loss phase, and a leveling off or soil binding phase. Approximately 50% of the strychnine was lost from the two soils within 24-27 days, with the appearance of a degradation product occurring early in the study. The initial breakdown products of strychnine are believed to be polar compounds with strong sorption characteristics.