can be obtained by pointwise multiplication of the residue and consumption distributions than by multiplying the quantiles obtained from the residue and consumption distributions, separately. Moreover, the probability distribution approach based on 1-year age groupings of children provides useful information on differences in exposure patterns for children 1 to 5 years of age.
Average daily ingestion of pesticide residues is an appropriate measure of exposure for chronic risk assessment, whereas actual individual daily ingestion is more appropriate for acute risk assessment.
Since chronic toxicity is often related to long-term average exposure, the average daily dietary exposure to pesticide residues may be used as the basis for risk assessment with delayed irreversible chronic toxic effects. To take into account different food consumption patterns among individuals, the distribution of average daily dietary intake of pesticides should be examined within the population of interest. Since acute toxicity is more often mediated by peak exposures occurring within a short period (e.g., over the course of a day or even during a single eating occasion), individual daily intakes are of interest for risk assessment for acute toxic effects. Examination of the distribution of individual daily intakes for persons within the population of interest reflects both day-to-day variation in pesticide ingestion for specific individuals as well as variation among individuals. This distribution can be used to estimate the number of person-days in a given period during which intake will exceed a specified level, such as the acceptable daily intake (ADI), or reference dose.
At present, there is a relatively limited amount of information on food consumption patterns of infants and children. To obtain accurate estimates of the distribution of individual intakes, more elaborate and more intensive consumption monitoring protocols are required.
Because residue monitoring surveys conducted for compliance purposes are expected to lead to higher residue levels than those present in the general food supply, assessment of human exposure should normally be based on surveillance surveys. In using surveillance data, however, consideration needs to be given to regional differences in pesticide use and resultant residue levels.
The committee acknowledges that pesticide food surveillance data are generated by randomly sampling food items from the distribution system. The purpose of this sampling is to ensure agricultural compliance with acceptable pesticide use practices. This sampling is broad-based and often not focused only on pesticides actually used. Pesticide field trial data are generated under strictly controlled conditions of use. These data better reflect actual levels at the time of harvest when it is known that a specific