Aggregate Risk Assessment:

            The Food Quality Protection Act requires an aggregate risk assessment.  Aggregate risk is the risk due to the exposure to a single substance from possibly multiple exposure pathways and routes.

            Sielken & Associates has models available that help determine the exposure from each of the exposure sources (e.g., drinking water ingestion, dietary consumption, pesticide handling).

            Some of the components of these exposure equations or models have values that are variable (varying between individuals, from year to year, from one food serving to another, from one pesticide use to another). The corresponding  exposure distribution describes the probability that an individual selected at random from the population will receive different specific doses via each of the three exposure routes and via the combined pathways.

            Instead of focusing on upper and lower bounds, Sielken & Associates develops and presents the distributional characterization of the dose from exposure, which provides the best estimate of the probability of being exposed to a given dose.  This tends to avoid the compounding of the multiple conservatisms associated with the regulatory default deterministic (non-probabilistic) assessments that exaggerate aggregate risks.

            Sielken & Associates has also helped develop methods that incorporate the relative potency of the different routes (e.g., oral ingestion, dermal, and inhalation) into the aggregate risk assessment.