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. Author manuscript; available in PMC: 2013 Feb 25.
Published in final edited form as: Neurotoxicology. 2010 Mar 1;31(3):297–304. doi: 10.1016/j.neuro.2010.02.005

Table 3.

Chlorpyrifos dose estimates for Egyptian cotton production workers during 2007 observational study.

Job
category
Worker
ID
Worker mean
daily dose
(ug/kg)1
Category mean
daily dose
(ug/kg)2
Margin of exposure
(target MOE >100)3
Engineer 1 1.69 1.0 150
3 0.74
4 0.59
Technician 1 61.3 29.7 5
2 14.3
3 13.6
Applicator 3 118.3 141.4 1
4 134.6
5 171.4
1

Worker mean daily dose based on two measurements for each worker; dose was calculated by the following equation: dose (ug/kg) = TCPy (ug/g creatinine) * 1.7 g creatinine/day * 1/0.7 * 1.766)/body weight (kg); creatinine clearance = 1.7 gram/day (ICRP Report of the Task Group on Reference Man, 1994); incomplete excretion factor = 0.7 (human oral dosing study by Nolan et al. 1984); chlorpyrifos molecular weight = 350.6, TCPy molecular weight = 198.5, chlorpyrifos equivalent factor = 1.766; body weights ranged from 65 to 88 kg, with weight for one worker imputed from weights of workers in the same job category.

2

Category mean dose is the mean of the three worker mean daily doses in each worker category

3

For comparison with biologically-based dose estimates, a dermal NOAEL of 5.0 mg/kgday * 0.03 dermal absorption factor was used (32, Table 8), resulting in a NOAEL = 150 ug/kg-day; Margin of Exposure (MOE) = NOAEL/dose; Target MOE > 100.