A benchtop system for evaluation of pesticide disposal by composting

Abstract A procedure for examining the feasibility of composting certain pesticides as a means for their disposal has been developed using a benchtop model compost system. This system is designed such that samples as small as 10 g can be studied, and, by using radiolabelled materials, compound transformation in compost media can be determined. Transformation of radiolabelled diazinon and chlordane has been examined using this procedure. After 3 weeks incubation under aerobic composting conditions (maximum temperature 65 °C), 21.6% of the diazinon radiolabel was recovered from the volatile organics trap. Of this, 15.1% was solvent extractable and was identified by TLC as diazinon and the hydrolysis product 2-isopropyl-7-methyl-6-hydroxypyrimidine (IMHP). This hydrolysis product was the only radiolabelled form present in solvent extracts of the compost media. Radiolabelled chlordane was recovered as the unconverted alpha and gamma forms with 49.6% volatilized and 47.8% remaining in the compost media.