Chlorpyrifos Protects


Biologic monitoring - Measuring hazardous substances in biologic materials (such as blood, hair, urine, or breath) to determine whether exposure has occurred.

Biological assessment of exposure - Assessment of exposure of a living organism to pesticides using biological specimens (blood, urine, etc.) taken in the environment (workplace, field, etc.) with analysis either directly by chemical determination of parent or metabolite, or indirectly by measurement of a relevant biochemical parameter (e.g., plasma cholinesterase activity for organophosphorus compounds).


Today’s analytical testing can detect the presence of many different substances at trace levels in urine. Routine government biomonitoring of the U.S. population commonly turns up measurable urinary levels of fire retardants, wood preservatives, paint additives, sun screens, metal alloys, plastic additives, soaps and deodorants, food preservatives and pesticides, including breakdown products of chlorpyrifos (primarily the metabolite TCP or trichloropyridinol). These substances are present in urine as a consequence of our living in an industrialized society, and reports issued by government health experts such as the Centers for Disease Control and Prevention consistently note that the presence of these compounds in urine at minute levels does not in itself have significance for health. Trace levels of the chlorpyrifos breakdown product TCP are commonly found in urine within the U.S. population, primarily as a result of its use in protecting food crops against insect pests. Correlating specific chlorpyrifos exposure levels with trace concentrations of TCP in urine is complicated by the fact that people also may ingest traces of TCP remaining on crops as a result of chlorpyrifos application and breakdown in the environment.

Further Resources

Centers for Disease Control and Prevention, National Biomonitoring Program:

“Measuring Chemical Presence in Humans: What Role for Biomonitoring?”, CropLife International:

“Perspectives on Biomonitoring”, CropLife America:

Morgan, M.K. et al. “The reliability of using urinary biomarkers to estimate children's exposures to chlorpyrifos and diazinon.” Journal of Exposure Science and Environmental Epidemiology, 2011, Volume 21(3):280-290. Available:

ATSDR glossary:

IUPAC pesticide glossary: