A multimedia, multiple pathway risk assessment of atrazine: the impact of age differentiated exposure including joint uncertainty and variability

This paper addresses the need to evaluate the differences in exposure to pesticides between children and adults. We present a framework for evaluating these differences in exposure to pesticides through multiple exposure pathways. The concentrations in all environmental media were determined as distributions in a companion paper. All parameter values utilized in the calculation of exposure and risk are considered to be distributions, resulting in distributions for output exposure and risk. A sensitivity analysis was completed to determine the relative importance of the parameters with respect to the outcome. A joint uncertainty and variability analysis was also completed to evaluate the relative contribution between uncertain and variable parameters. Exposure to atrazine by a mid-western farming family is presented as a case study. The predicted exposure for a child based on a 14-year exposure period was 1.6 times that calculated using lifetime averaged exposure parameters. This indicates the importance of considering children as a population sub-group when calculating the exposure and risk to pesticides.