Organophosphate Concentrations in Breast Milk of Postpartum Mothers in Agricultural Area of Thailand

Abstract

This cross-sectional study aimed to study the following organophosphate (OP) concentrations, omethoate, demeton-s-methyl, dimethoate, tolclofos-s-methyl, pirimiphos-methyl, malathion, chlorpyrifos, methidathion, ethion and pyrazophos in breast milk of 2-month postpartum mothers. The 51 study subjects lived in Kanchanaburi, Nakhonsawan, Amnatcharoen province. The subjects were interviewed using questionnaire about general characteristics of the subjects and their infants and insecticide exposure in the past two month. The organophosphate concentrations were extracted by Quick Easy Cheap Effective Rugged Safe (QuEChERS), determined by Chromatography Mass Spectrometry (GC-MS).  The recoveries of each OP analysis method ranged from 90.05% to 109.71% at OPs concentrations of 25, 75 ng/ mL; the between-day assay coefficients of variation were in the range of 1.71% to 8.77%. The detection limit of OPs ranged from 0.90 to 1.90 ng/ml breast milk. The results found omethoate, chlorpyrifos and ethion for 17.6, 41.2 and 41.2% in breast milk samples. Furthermore, the average daily intake of omethoate chlorpyrifos and ethion in breast fed  2-month infants are above the acceptable daily intake (ADI) 100 14.3 and 71.2% recommended by World health Organization/Food and Agricultural Organization (WHO/FAO).