DEGRADATION OF TERMITICIDES TREATED WOOD: ORGANOPHOSPHATE AND SYNTHETIC PYRETHROID GROUP I: Method of chemical analysis

Abstract

Degradation of 4 synthetic pyrethroids and 2 organophosphate termiticides treated wood blocks. brush treated with 0.5%, 1% and 2% concentration at a rate of 110 + 10 g/m² to unsterile soil burial and then weathering for the periods of P1 (soil burial and weathering for 1 and 11 months in shade room condition), P2 (soil burial and weathering for 3 and 9 months in shade room condition), P3 (soil burial and weathering for 6 and 6 months in shade room condition) and P4 (soil burial for 12 month and suddenly extraction of the remaining chemicals) by method of chemical analyses which was conducted by Gas Chromatography (G.C) to determine recovery rate after soil burial and weathering. Results showed that many factors such as type of termiticides, concentration use and periods of soil burial and weathering that affected to the difference on chemical degradation of treated wood blocks. Since it was found that percent recovery of chemicals increased with higher concentration, and decreased with the longer periods of soil burial and weathering. The organophosphate termiticide; chlorpyrifos and phoxim were found to be the most susceptible to dcgradation in tropical soil burial and weathering and more easily and rapidly degradated in soil condition than synthetic pyrethroid termiticides even at the highest concentration. For synthetic pyrethroid termiticides; permethrin and cypermethrin were more easily degradated than fenvalerate and Hoe-498 respectively, and rapidly broken down especially at low concentration. After 12 months of soil burial, these synthetic pyrethroid terthroid termiticides were also more degradated to almost the same as orgnophosphate termiticides except Hoc-489, which was found to be the most stable to degradate in tropical soil condition and weathering comparing with the others chemicals tested at all concentration