Cholinesterase activity as a biological indicator of exposure to pesticides

Summary Cholinesterase activity measurement should be considered in relationship to its proposed use, whether for diagnostic information, a monitor of health status or because of its logistical and economic practicality. To prevent confusion one must consider that measurement of cholinesterase activity may confirm the existence of poisoning by an inhibitor, may measure an individual worker's overall exposure or his characteristic individual response. Where groups of workers are involved a group response may be derived to identify the magnitude of the response at some preset value of significance from which a biological threshold limit value may be established. The population at risk, the intensity and frequency of exposure dictate the frequency of sampling. Pesticide exposed workers are grouped according to confined and unconfined environments. Confined environments are those associated with manufacturing, formulating and warehousing of pesticidal products. Unconfined environments are those associated with application and postapplication exposures. All of the aforementioned factors must be considered before employing cholinesterase activity measurement as an index of exposure to pesticides.