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Uncertainty in Measurements of Dermal Absorption of Pesticides
Author(s) -
Navidi William C.,
Bunge Annette L.
Publication year - 2002
Publication title -
risk analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.972
H-Index - 130
eISSN - 1539-6924
pISSN - 0272-4332
DOI - 10.1111/1539-6924.00281
Subject(s) - confidence interval , replicate , statistics , pesticide , absorption (acoustics) , pooling , hexaconazole , mathematics , chemistry , toxicology , environmental science , computer science , optics , physics , biology , agronomy , botany , artificial intelligence , fungicide , carbendazim
Dermal absorption experiments form an important component in the assessment of risk from exposure to pesticides and other substances. Much dermal absorption data is gathered in rat experiments carried out using a certain standard protocol. Uncertainties in these data arise from many sources and can be quite large. For example, measurements of the systemic absorption of hexaconazole differed by more than an order of magnitude within a single experiment. Two diniconazole studies produced quite different results, due to minor differences in protocol and in chemical formulation. Limits of detection can also prevent accurate measurement when the amounts absorbed are small. These examples illustrate the need for measuring and reporting uncertainties in estimates that are based on these data. The most direct way to estimate uncertainty is to compute the sample standard deviations of replicate measurements. By pooling these estimates across dose and duration groups for which they are similar, the number of degrees of freedom is increased, and more precise confidence intervals can be obtained. In particular, the ratio of upper to lower 95% confidence limits was reduced by as much as ten‐fold for hexaconazole, seven‐fold for uniconazole, and nearly four‐fold for propiconazole.