Physiologically-Based Kinetic Computer Model of Organophosphorus Pesticides and Metabolites Kinetics During Human Pregnancy
Organophosphorus (OP) pesticides are widely used in homes and farmland areas, and close proximity of family homes to orchards greatly increases the risk of children's exposure to these chemicals (Lu 2000). Previous studies have determined levels of metabolite in urine following exposure to pesticides for adults and children. Pregnancy is a special, complicated variation of this exposure that has not been examined closely. Morals involved in the study of exposure to harmful chemicals during human pregnancy restrict the amount of data available. A physiologically-based kinetic computer model will be used to track OP chemicals (chlorpyrifos and azinphosmethyl) and their resulting metabolites in maternal and fetal tissues throughout the course of a human pregnancy. SAAM II is a computer program developed at the University of Washington to simulate physiological systems by using either compartmental or numerical models. A compartmental model will represent the maternal and fetal organs and the interactions between mother and fetus from the time of conception to birth. Mathematical equations within the program will govern the growth rate of the fetal and maternal organs and changes in blood flow rate between these organs that occur during pregnancy. Parameters and coefficients for these equations will be derived from research involving pharmacokinetic studies on pregnancy and exposure in other animals and studies on organs, such as the placenta. Important data on how pesticides travel through the body of mother and fetus will be gained during this study. The model will also provide information on the amount of urinary metabolites excreted by the mother following estimated doses; this information will shed new light on the relationship between urinary metabolite concentration and fetal/maternal health risks.
