Chlorpyrifos exposure and biological monitoring among manufacturing workers: Table 1

Abstract

Aim: To use biological monitoring data to evaluate the soundness of job based exposure classifications. Methods: The authors studied 52 chlorpyrifos manufacturing workers and 60 referent workers to compare chlorpyrifos exposure estimations from job titles and work areas to urinary excretion of 3,5,6 trichloro-2-pyridinol (TCP), a metabolite of chlorpyrifos. Work history records and industrial hygiene monitoring data were used to establish cumulative interim exposure. Chlorpyrifos exposure during the study year was assessed biologically by urinary excretion of TCP. Results: Exposure as measured by three urinary TCP samples was significantly higher among the chlorpyrifos workers (188 mg/l) than it was for the referent subjects (7 mg/l). Urinary TCP also correlated well with specific exposure categories of negligible (0.73-1.98 mg/m 3 days), low (1.99-4.91 mg/m 3 days), and moderate (4.92-15.36 mg/ m 3 days). The weighted Kappa coefficient was 0.80 (95% CI 0.72 to 0.87) for the mean TCP over the study period. Conclusions: The estimates of chlorpyrifos exposure based on job classifications and industrial hygiene measurements were significantly related to urinary TCP excretion, indicating that the ambient estimates are useful for providing exposure estimates among chlorpyrifos manufacturing workers. J ob titles, tasks, and work areas have been used in epidemiology studies as surrogate indicators of exposure to organophosphorus insecticides. However, biological exposure markers of specific organophosphorus compounds have not been used to confirm or quantify these estimates of workers' exposure. Monthly measurements of butyrylcholinesterase (BuChE, plasma cholinesterase) activity are often collected among chlorpyrifos applicators and manufacturing workers. Whereas the degree of inhibition of BuChE has been demonstrated to correlate with job based exposure categories, 1 BuChE is characterised by a high degree of intraindividual variability.2 3 Quantifying the excretion in urine of the principal metabolite of chlorpyrifos, 3,5,6-trichloro-2-pyridinol (TCP) as opposed to enzyme activity is a more specific marker of exposure. The purpose of the current analyses was to use urinary TCP data among chlorpyrifos manufacturing workers to validate the use of job based exposure classifications used in health studies. The present study was conducted as part of a prospective investigation of neurological and neurobehavioural function in chlorpyrifos manufacturing workers. 4 METHODSAll chlorpyrifos manufacturing workers employed at a Michigan facility on 1 September 1999 were asked to participate. Saran manufacturing workers were chosen as a referent population. Fifty two of the 66 eligible chlorpyrifos workers (80%) participated and 60 of the 74 (81%) randomly selected Saran workers participated. The referent workers were similar to the chlorpyrifos workers with respect to age (mean 41 years for both), weight (88 kg for both), and education (14 years for both).Measurements of urinary TCP excretion were collected from each subject o...

Paraoxonase status and plasma butyrylcholinesterase activity in chlorpyrifos manufacturing workers

“…Our regression analyses showed that BuChE activity, as a biological measure of chlorpyrifos exposure, was significantly related to average TCP/Cr excretion averaged over the year of observation (a quantitative biological measure chlorpyrifos dose), a finding consistent with our previous report (Burns et al, 2006). We recognize that the relationship between measures of BuChE activity and TCP/Cr excretion is dynamic and that averaging the values for each measure throughout the year could possibly obscure or blunt the relationship between the two measures.…”

“…The spring sample was given a weight of 1 month because chlorpyrifos is typically used on home gardens and farms during a 1-month period in the spring when crops emerge. The samples taken during the baseline and 1 year physical examinations were each given a weight of 5.75 months (Burns et al, 2006).…”

Multiple pesticides exposure of greenhouse workers and thyroid parameters

“…Chlorpyrifos is the major representative of the organophosphorus insecticides that are widely used in agriculture and even with all restrictions of their use, they still account for 50% of all pesticide applications worldwide. These compounds receive an increasing consideration as potential endocrine disrupters [21][22][23][24]. Chlorpyrifos is rapidly metabolized and excreted in the urine.…”

Cholinesterase inhibition in chlorpyrifos workers: Characterization of biomarkers of exposure and response in relation to urinary TCPy

“…The study population was previously described in publications by Burns et al (2006) and Albers et al (2004aAlbers et al ( , b, c, 2007. Briefly, the study group consisted of 53 CPF manufacturing workers and a referent group of 60 workers in the Saran manufacturing process with no occupational exposure to organophosphate pesticides or ChE inhibitors (Table 1).…”