Determinants of Exposure to Captan in Fruit Growing

Cock, J. de; Heederik, Dick; Boleij, J.S.M.; Kromhout, Hans; Hoek, F.; Wegh, Hillion; Ny, E. Tjoe

doi:10.1202/0002-8894(1998)059<0166:doetci>2.0.co;2

Cited by 4 publications

(9 citation statements)

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“…However, large loss of captan was shown under dry conditions in another field study (Smith and MacHardy 1984), which may have resulted from heavy dew. Several papers have stated that the half-life of captan on vegetation is between 3 and 17 days, but no detailed data were provided (De Cock et al 1998;Decision 1999). Without rainfall such a short half-life time is most unlikely and may result from not taking growth dilution effects into consideration.…”

Section: Model Parameters For Captanmentioning

confidence: 99%

Modelling non-systemic pesticide residues in fruits with initial deposit variability and weather effects

Huo

Salazar

Hyder

et al. 2007

Food Additives & Contaminants

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A flexible and generic model was developed to predict the decline of residues of a non-systemic pesticide for both single and multi-spray situations as well as for different tree canopy zones. The model predicts not only the average residue levels, but also the confidence interval of the residues through either a deterministic or a stochastic approach. This generic model includes several key aspects of residue fates in the environment: initial deposit, physical loss and growth dilution. The model considers a tree canopy in three distinct zones for which initial deposition of pesticides may differ. In addition to predicting the average residue within each zone, it also estimates the 95 and 99% confidence intervals of residues on individual fruit within each zone. For the purpose of evaluation, this model was parameterized specifically for captan, one of the most important non-systemic fungicides used to control disease in horticultural crops. The observed average initial deposit for each zone was used in the evaluation. The overall correlation between predicted average residues and those observed on apple fruit in two applications was 0.93. Confidence intervals were also predicted accurately.

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Section: Model Parameters For Captanmentioning

confidence: 99%

Modelling non-systemic pesticide residues in fruits with initial deposit variability and weather effects

Huo

Salazar

Hyder

et al. 2007

Food Additives & Contaminants

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“…*Author to whom correspondence should be addressed. Tel: 1-513-841-4453; fax: 1-513-841-4456; e-mail: chines@cdc.gov dislodgeable foliar residues) (de Cock et al, 1998). Even among applicators, exposure determinants may differ for private and commercial applicators due to differences in the amount and duration of spraying and methods used for spraying and mixing.…”

Section: Introductionmentioning

confidence: 99%

Determinants of Captan Air and Dermal Exposures among Orchard Pesticide Applicators in the Agricultural Health Study

2011

The Annals of Occupational Hygiene

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confidence: 99%

“…In fact, these farm workers were at high risk of direct exposure to pesticides while mixing, loading, or spraying pesticide. [1][2][3][4] It has been reported that chlorpyrifos insecticide is rapidly absorbed by skin contact and/or oral administration, metabolized and excreted by mammals.5) The primary mechanism of action of organophosphorus (OP) insecticides like chlorpyrifos involves the inhibition of acetylcholinesterase (AChE), resulting in a wide range of neurotoxic effects in humans, such as sensory and motor neuropathy with permanent paralysis. The inhibition of cholinesterase enzyme (ChE) may cause acetylcholine accumulation at the synaptic cleft, causing the stimulation of autonomic receptors and depolarizing blocks of neuromuscular junction receptors in the human body.…”

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confidence: 99%

Spectrophotometric Determination of Plasma and Red Blood Cell Cholinesterase Activity of 53 Fruit Farm Workers Pre- and Post-Exposed Chlorpyrifos for One Fruit Crop

Thetkathuek

Keifer²,

Fungladda

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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Chlorpyrifos (O,O-diethyl 0-(3,5,6-trichloro-2-pyridyl) phosphorothioate) belongs to the organophosphate insecticide (OPs) family, and is widely used to kill aphids in fruit farms. The demand for this insecticide is increasing. To our knowledge, there is no biological monitoring data for fruitfarm worker exposure to chlorpyrifos insecticide is available in Thailand. Biological monitoring is an essential component of any comprehensive assessment of exposure. In fact, these farm workers were at high risk of direct exposure to pesticides while mixing, loading, or spraying pesticide. [1][2][3][4] It has been reported that chlorpyrifos insecticide is rapidly absorbed by skin contact and/or oral administration, metabolized and excreted by mammals.5) The primary mechanism of action of organophosphorus (OP) insecticides like chlorpyrifos involves the inhibition of acetylcholinesterase (AChE), resulting in a wide range of neurotoxic effects in humans, such as sensory and motor neuropathy with permanent paralysis. The inhibition of cholinesterase enzyme (ChE) may cause acetylcholine accumulation at the synaptic cleft, causing the stimulation of autonomic receptors and depolarizing blocks of neuromuscular junction receptors in the human body. In addition, it was proposed that both long-term exposure to subclinical doses of OP, and after acute intoxication, could be responsible for chronic OP-induced neuropsychiatric disorders. [6][7][8][9] ChE can be used as an index of cholinergic function and changes in enzyme activity may indicate alterations in the availability of acetylcholine at the receptor level. [10][11][12][13][14] In vivo, ChE activity reflecting the functional quantities of the enzyme can be assessed using blood, plasma, and red blood cells. Inhibition of ChE leads to a down-regulation of cholinergic receptors. The levels of ChE appear to be controlled by the interaction of acetylcholine with its receptors, with enhanced interaction increasing the levels of ChE. 15)This study aims to investigate any changes in ChE activity reflecting the cholinergic function of fruit farm workers exposed to the neurotoxin, chlorpyrifos insecticide, during one fruit crop. For this purpose, the blood ChE activities of 53 farm workers on fruit farms in Rayong Province, Thailand, were collected and analyzed.In the present study, a significant decrease in plasma (PChE), but not red blood cell ChE (AChE) activity after exposure to chlorpyrifos in the spraying season, compared with the non-spraying season, was found. The results suggest an interaction between chlorpyrifos and monoaminergic-cholinergic neurotransmission that leads to a decrease in the functional enzyme available to degrade acetylcholine. We propose that PChE activity can be used as a biomarker for monitoring early toxicity induced by chlorpyrifos insecticide. Determination of baseline red blood cell and plasma cholinesterase activity among applicators in the non-spraying season is very important, before identifying the effects of these pesticide exposures. Experiment...

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Determinants of Exposure to Captan in Fruit Growing

Cited by 4 publications

References 0 publications

Modelling non-systemic pesticide residues in fruits with initial deposit variability and weather effects

Modelling non-systemic pesticide residues in fruits with initial deposit variability and weather effects

Determinants of Captan Air and Dermal Exposures among Orchard Pesticide Applicators in the Agricultural Health Study

Spectrophotometric Determination of Plasma and Red Blood Cell Cholinesterase Activity of 53 Fruit Farm Workers Pre- and Post-Exposed Chlorpyrifos for One Fruit Crop

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