Chlorpyrifos biomonitoring data

Table 4 Statistical (Probability) Analysis of Chlorpyrifos Biomonitoring Data for Mixer-Loaders and Applicators...

Table 3 Estimated Margins of Exposure for Chlorpyrifos from Biomonitoring Data Using Geometric Means (Single-Point Approach)3...

Potential dermal exposure (PDE) was the sum of the amount of chlorpyrifos retained by the dosimeter (socks, gloves, and union suit) during the 20-min exposure period. Absorbed daily dose (ADD) was the sum of chlorpyrifos equivalents measured in urine for days 2,3, and 4. Home-use biomonitoring data are expressed as chlorpyrifos equivalents per day, as exposure continued throughout the test period. 

Barr, D.B., and J. Angerer. In press. Potential uses of biomonitoring data A case study using the organophosphorus pesticides chlorpyrifos and malathion. Environ Health Perspect. [online]. Available http //ehp.niehs.nih.gov/docs/2006/9062/abstract.html [accessed Aug. 21,2006],... 

Chlorpyrifos provides an example of the utility of human pharmacokinetic models to estimate daily dose from biomonitoring data for a rapidly cleared pesticide. The urinary metabolite trichloro-2-pyridinol (TCP) is used in the NHANES study to monitor population exposure to chlorpyrifos (CDC 2005). Several epidemiologic studies have linked chlorpyrifos exposure to adverse birth outcomes through associations between urinary and blood biomarkers and have demonstrated maternal exposure and physiologic measurements in the neonate (Berkowitz et al. 2003, 2004 Whyatt et al. 2004 Needham 2005). 

Assessments of risks associated with the use of chlorpyrifos insecticide products for workers have been made. The assessments are based on the results of field studies conducted in citrus groves, a Christmas tree farm, cauliflower and tomato fields, and greenhouses that utilized both passive dosimetry and biomonitoring techniques to determine exposure. The biomonitoring results likely provide the best estimate of absorbed dose of chlorpyrifos, and these have been compared to the acute and chronic no observed effect levels (NOELs) for chlorpyrifos. Standard margin-of-exposure (MOE) calculations using the geometric mean of the data are performed however, probability (Student s f-test) and distributional (Monte Carlo simulation) analyses are deemed to provide more realistic evaluations of exposure and risk to the exposed population. 

Table 1.4 Comparison of concurrent biomonitoring and passive dosimetry data s from chlorpyrifos exposure studies (USEPA, 2001)...

---