Determinants of Exposure to Captan in Fruit Growing

Abstract

A series of studies investigated occupational exposure to pesticides among fruit growers in The Netherlands during spraying and reentry of orchards between 1990 and 1992 to identify and quantify determinants of exposure. Determinants of exposure are discussed as a starting point for hazard identification and control. Captan was used as a marker for exposure. Cabin use of the tractor was the most prominent determinant of dermal exposure during spraying. For respiratory exposure, factors related to preparation of pesticides were most prominent. A long duration of exposure may reflect a different exposure situation compared with a short duration of exposure. As different determinants of exposure prevailed for each subgroup, consideration should be given to constructing exposure models for each group separately. Dislodgeable foliar residue (DFR) was the most prominent determinant of exposure for both respiratory and dermal exposure during reentry. However, no significant relation between DFR and dermal exposure of forehead and sternal area was found, perhaps because there was no direct contact with foliage here. Therefore, use of a transfer factor based on DFR to estimate total dermal exposure is only a crude estimate. The half-life of captan on crops varied from 10-17 days, so substantial exposure when entering the orchard is very likely, particularly when spraying frequency is high. The main starting points for reduction of exposure are use of a cabin, DFR, and individual time spent on different tasks. Determinants that are constant over time (cabin use) may have an especially great influence on grouping workers, according to long-term exposure in epidemiological studies. As determinants of exposure vary for the different exposure routes and body locations (for dermal exposure), the measure of interest for a specific study design will decide which determinants are most relevant.

Agricultural task and exposure to organophosphate pesticides among farmworkers.

“…De Cock et al (1998a, 1998b reported that exposure intensity for orchard thinning is about twice that of orchard harvesting or pruning. This may be due to the workers' substantial physical contact with tree foliage or to the high dermal absorption of pesticides such as azinphosmethyl .…”

Urine mutagenicity and lymphocyte DNA damage in fruit growers occupationally exposed to the fungicide captan

“…De Cock et al measured levels of cutaneous contamination ranging from 0.47 to 48.6 mg/h/m 2 , depending on pad location and type of spraying equipment. 34 Few models are currently available to simultaneously consider a set of quantitative (amount handled, duration of exposure, etc) as well as qualitative (protection used) exposure parameters. The UK-POEM is among those used for registration purposes in European countries.…”

A method for assessing occupational pesticide exposures of farmworkers

“…Two used the same pesticide (captan) [Zweig et al 1985;De Cock, 1998a,b], but the application rate was available only for one [Zweig et al, 1985]. Ratio of pesticides on hands and forearms was 7.2 [Zweig et al,1983] DFR Body r 0.90 [Zweig et al,1985] DFR Body r 0.50^0.57, reported as a range [McCurdy et al,1994] DFR Hands,wrists, arm, Statistically significant [De Cock et al,1998b] forehead DFR Estimated whole body Graphical representation showed body exposure increased with DFR. Using only the ®rst study for captan [Zweig et al, 1985], the exposure intensity was normalized for the amount of pesticide applied.…”