Cholinesterase Depression and Its Association with Pesticide Exposure across the Agricultural Season among Latino Farmworkers in North Carolina

Abstract

BackgroundFarmworkers can be exposed to a wide variety of pesticides. Assessing cholinesterase activity over time can be used to monitor exposure to organophosphorus and carbamate pesticides.ObjectivesThe goal of this study was to document patterns and variation in cholinesterase levels across the agricultural season (May–August) among field-workers, and to explore the association of cholinesterase depression with pesticide exposure across the agricultural season.MethodsDried blood samples collected from 231 migrant farmworkers sampled from camps in eastern North Carolina up to four times across a summer agricultural season were analyzed for cholinesterase activity, and urine samples were analyzed for metabolites of organophosphorus and carbamate pesticides. Reductions of ≥ 15% from an individual’s highest value were identified and considered evidence of meaningful cholinesterase activity depression.ResultsThe average cholinesterase activity levels were lowest in June, with significantly higher mean values in July and August. When adjusted for age, sex, minutes waited to shower, and days worked in the fields, the number of organophosphorus and carbamate pesticides detected in urine predicted reductions in cholinesterase activity.ConclusionsThese data demonstrate that workers are experiencing pesticide exposure. Greater enforcement of existing safety regulations or strengthening of these regulations may be warranted. This study demonstrates that serial measurements of cholinesterase activity across an agricultural season can detect exposure to pesticides among field-workers.

Longitudinal assessment of chlorpyrifos exposure and self-reported neurological symptoms in adolescent pesticide applicators

“…An additional limitation often encountered by past studies was the absence of established baseline AChE and BChE levels. A recent adult study examining the variation of ChE levels among OP pesticides and carbamate-exposed fieldworkers could not establish any baseline AChE/BChE due to the mobility of the migrant study population 40. Another Egyptian adolescent study also reported a greater reduction of AChE activity among pesticide applicators compared to controls 20 21.…”

Longitudinal Assessment of Blood Cholinesterase Activities Over 2 Consecutive Years Among Latino Nonfarmworkers and Pesticide-Exposed Farmworkers in North Carolina

“…We showed that cholinesterase activity was significantly lower later in the summer and that depressions in cholinesterase activity were related to the number of different organophosphorus and carbamate pesticide metabolites detected in urine. 15 That study had several shortcomings, including cholinesterase data from just a single year; lack of a comparison group; no information on potential residential pesticide exposure; and cholinesterase obtained from dried whole blood samples, preventing differentiation of acetylcholinesterase and butyrylcholinesterase activities. The current study was designed to remedy these shortcomings to more definitively assess evidence of work-related exposure to cholinesterase-inhibiting pesticides.…”

Dried blood spots in toxicology: from the cradle to the grave?

“…It needs to be remarked, though, that sensitivity is rather limited and ideally one should know an individual's enzyme activity prior to exposure, with only considerable intoxications resulting in a significant decrease in enzyme activity. Yet, multiple other publications have shown the potential to use (dried) blood and plasma spots for monitoring cholinesterase activity, primarily for occupational surveillance of exposed workers (Augustinsson and Holmstedt, 1965, Holmstedt and Oudart, 1966, Collombel and Perrot, 1970, Oudart and Holmstedt, 1970, Augustinsson et al, 1978, Eriksson and Faijersson, 1980, Rhyanen et al, 1984, Hilborn and Padilla, 2004, Quandt et al, 2010. Several of the DBS applications for monitoring environmental contaminants are discussed more into depth below.…”

“…LC-MS/MS GC-MS Jantos and Skopp, 2011;Jantos et al, 2011b;Lauer et al, 2011 Langel et al, Henderson et al, 1993Henderson et al, 1997Mercolini et al, 2010Sosnoff et al, 1996Alfazil and Anderson, 2008;Lauer et al, 2011Langel et al, 2011 Benzodiazepines LC-MS/MS GC-MS Alfazil and Anderson, 2008;Havard et al, 2010;Thomas et al, 2010;Jantos and Skopp, 2011;Lauer et al, 2011 Langel et Boy et al, 2008;Thomas et al, 2010;Marin et al, 2010;Clavijo et al, 2011a;Jantos et al, 2011a;Lauer et al, 2011Langel et al, 2011 Buprenorphine and metabolites Thomas et al, 2010;Marin et al, 2010, Lauer et al, 2011 Heilbronn, 1953;Augustinsson and Heimburger, 1953;Augustinsson and Holmstedt, 1965;Holmstedt and Oudart, 1966;Collombel and Perrot, 1970;Oudart and Holmstedt, 1970;Augustinsson et al, 1978;Eriksson and Faijersson, 1980;Rhyanen et al, 1984;Hilborn and Padilla, 2004;Trudeau et al, 2007;Quandt et al, 2010 Table 1. Overview of the analytes discussed in this review, with referral to the utilized analytical techniques.…”