Diethyl phosphates accumulation in rabbits’ hair as an indicator of long term exposure to diazinon and chlorpyrifos

Long term exposure to organophosphate pesticides can be evaluated by quantitative analysis of their non-specific metabolites in hair matrix. The aim of this study was to determine whether these metabolites can be internally incorporated into the hair of rabbits exposed to diazinon and chlorpyrifos. The influence of dose and dose duration of each pesticide dosage were investigated. Three groups of rabbits were exposed to different dosages of diazinon (3.0 and 6.0 mg/kg/day) and chlorpyrifos (18.0 mg/kg/day) via drinking water. Hair samples were collected every month and analyzed for diethyl phosphate (DEP) and diethyl thiophosphate (DETP) by gas chromatography–mass spectrometry (GC–MS). The mean concentrations of the low-dose treated group, ranged from 112 to 257 pg/mg for DEP and from 295 to 515 pg/mg for DETP in hair. The high-dose treated group demonstrated a range of mean concentrations from 142 to 585 pg/mg for DEP and from 406 to 988 pg/mg for DETP in hair. For the chlorpyrifos treated group, the concentrations ranged from 138 to 1070 for DEP and from 554 to 886 pg/mg for DETP. Analysis revealed the incorporation of these metabolites into the rabbit hair in a dosage and dose duration-dependent manner. These data confirms the ability of using hair analysis for diethyl phosphates to assess long-term OP exposure.