 in exposure or risk assessments , both environmental and biological measurements are often used . 
 environmental measurements are an excellent means for evaluating regulatory compliance , but the models used to estimate body burden from these measurements are complex . 
 unless all possible routes of exposure ( i.e. , inhalation , dermal absorption , ingestion ) are evaluated , exposure to a toxicant can be underestimated . to circumvent this problem , 
 measurements of the internal dose of a toxicant in blood , serum , urine , or tissues can be used singularly or in combination with environmental data for exposure assessment . in three separate laboratories , carbaryl or its primary metabolite , 1-naphthol , was measured in personal air , dermal samples , blood serum , and urine from farmer applicators and their families . 
 the usefulness of both environmental and biological data has been demonstrated . 
 for the farmer applicator , the environmental levels of carbaryl would have been sufficient to determine that an exposure had occurred . however , biological measurements were necessary to determine the absorbed dose of each member of the applicator 's family . 
 in addition , a correlation between serum and urinary 1-naphthol measurements has been shown ; therefore , either matrix can be used to accurately evaluate occupational carbaryl exposure.imagesfigure 1.figure 2.figure 3.figure 4.figure 5 . 
 afigure 5 . 
 b 
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