A multiyear study of blood cholinesterase activity in urban pesticide applicators

Yeary, Roger A.; Eaton, J. K.; Gilmore, Edith; North, Ben; Singell, Jan

doi:10.1080/15287399309531733

Cited by 30 publications

(10 citation statements)

References 9 publications

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“…Nevertheless, this difference could be attributed to the fact that in the March-April period higher exposure to pesticides produced a reduction in the concentration of PChE. In this context it should be noted that several pesticides, such as organophosphates and carbamates (most used by these workers), are reported to be the major cause of a depression of serum cholinesterases (Yeary et al, 1993) and, as consequence, this is used as a good biomarker of exposure.…”

Section: Resultsmentioning

confidence: 99%

A follow-up study on micronucleus frequency in Spanish agricultural workers exposed to pesticides

Pastor

Lucero²,

Gutiérrez³

et al. 2002

Mutagenesis

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To determine whether occupational exposure to a complex mixture of pesticides results in a significant increase in the level of cytogenetic damage, a follow-up study was planned on 39 greenhouse workers from Almería (southeastern Spain). Taking into account that pesticide exposure can be season-related, two blood samples were taken from each individual at different times: one in a period of high exposure (sample A, spring-summer) and the other in a period of lower exposure (sample B, autumn-winter). Using the cytokinesis block micronucleus technique the frequency of binucleated cells with micronuclei (BNMN) and the cytokinesis blocked proliferation index (CBPI) were determined in peripheral blood lymphocytes. The results obtained indicate that there were no statistically significant differences in BNMN frequencies between the two sampling periods nor between exposed and controls. ANCOVA analysis of repeated measures revealed that the age of the individuals showed a direct relation with BNMN in the first study period. With regard to CBPI, a significant and season-related effect was found.

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Section: Resultsmentioning

confidence: 99%

A follow-up study on micronucleus frequency in Spanish agricultural workers exposed to pesticides

Pastor

Lucero²,

Gutiérrez³

et al. 2002

Mutagenesis

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“…Superoxide dismutase (SOD) is a major zinc/copper enzyme responsible for the dismutation of superoxide radicals generated by the autooxidation of hemoglobin, whereas d-aminolevulinic acid dehydratase (ALAD), a sulfhydryl enzyme, is essential for the synthesis of hemoglobin. Exposure to organophosphates and carbamates is reported to be the major cause of the depression of cholinesterase (an enzyme that catalyzes the hydrolysis of choline) in the blood of farm workers, though certain liver conditions can also inhibit the enzyme (IARC 1991;Yearly et al 1993). Many chemicals and toxic metals are known to alter the activities of these important enzymes because of the vicinal sulfhydryl group that is essential for the activity of ALAD (Maines 1980), whereas the zinc and copper atoms in SOD can be easily displaced by toxic metals such as cadmium (Linder 1991;Friberg et al 1985).…”

Section: Introductionmentioning

confidence: 99%

Occupational exposure to agricultural chemicals: effect on the activities of some enzymes in the blood of farm workers

Panemangalore¹,

Dowla²,

Byers³

1999

International Archives of Occupational and Environmental Health

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“…Following chronic exposures to OPs, RBC AChE activity can be depressed gradually to very low levels without clinical effects (Heath & Vale, 1992). An 11-yr study, conducted by ChemLawn Services Corporation from 1981 to 1991, reported that 150 of 33,717 urban pesticide applicators were removed from work when a 30% reduction in RBC AChE activity was found following exposure to ChE inhibiting insecticides (Yeary et al, 1993). However, no employee, with the exception of two suicide attempts, exhibited signs of toxicity or cholinergic effects.…”

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confidence: 98%

Regulating and Assessing Risks of Cholinesterase-Inhibiting Pesticides: Divergent Approaches and Interpretations

Chen²,

Eb³

et al. 1999

Journal of Toxicology and Environmental Health, Part B

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This document presents a revised framework for conducting worker and dietary risk assessments for less-than-lifetime exposures to organophosphate or carbamate pesticides based on red blood cell (RBC) or brain acetylcholinesterase (AChE) inhibition or the presence of clinical signs and symptoms. The proposals for appropriate uncertainty factors are based on the biological significance of the cholinesterase (ChE) inhibition noted at the lowest-observed-effect level (LOEL) and the degree of uncertainty in the extrapolation between human and animal data. An extensive evaluation of industry data, not previously summarized, and the available literature indicate that the following risk assessment principles are supportable and protective of human health: Plasma ChE inhibition is not an adverse effect, and therefore should not be utilized in risk assessments. Red blood cell AChE is not associated with the nervous system and inhibition is not per se an adverse (neurotoxic) effect. When available, cholinergic effects or brain AChE inhibition data should take precedence over RBC AChE for determining no-observed-effect levels (NOELs). When available, human RBC AChE inhibition or cholinergic effects data should take precedence over animal data for determining NOELs. Due to the lack of adversity associated with inhibition of RBC AChE, the use of a 10-fold (10x) uncertainty factor from the NOEL is adequate when RBC AChE inhibition data from either animal or human studies are used to assess human risk. Due to greater potential for adversity, NOELs for brain AChE inhibition and cholinergic effects identified in animal studies should receive a default uncertainty factor of 100x; lower uncertainty factors may be used on a case-by-case basis. NOELs based on cholinergic effects noted in human studies should only require a 10x uncertainty factor, since an interspecies extrapolation factor from animals to humans is unnecessary. For RBC and brain AChE activity the threshold for defining a NOEL should be less than or equal to 20% difference from control activity in all species. For risk assessment purposes, duration and route of the study should reflect the expected duration and route of exposure for humans (i.e., a 21-d or 28-d dermal study for subchronic occupational dermal exposure assessment). When dermal data are not available, a subchronic oral toxicity study and an appropriate dermal penetration factor should be used. A general default of 10% absorption should be used, analogous to the United Kingdom and German exposure models that are widely used in Europe. The recommendations in this document are generally consistent with current risk assessment procedures used by Canada, the European Community (EC), and the United Kingdom (UK).

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A multiyear study of blood cholinesterase activity in urban pesticide applicators

Cited by 30 publications

References 9 publications

A follow-up study on micronucleus frequency in Spanish agricultural workers exposed to pesticides

A follow-up study on micronucleus frequency in Spanish agricultural workers exposed to pesticides

Occupational exposure to agricultural chemicals: effect on the activities of some enzymes in the blood of farm workers

Regulating and Assessing Risks of Cholinesterase-Inhibiting Pesticides: Divergent Approaches and Interpretations

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