Understanding Dose vs Exposure John works applying pesticide X to agricultural fields. He spent the morning cleaning out a tank that had contained concentrated pesticide X. The tank was large and he was standing in water all morning (4 hours) power washing the tank. Human skin is a wonderful barrier to entry of compounds as long as it is dry and intact, but wet wrinkly skin can absorb toxins. About 5% of pesticide X absorbs into wet skin and John was in contact with water that had a total of 32 g of the pesticide in it.
After the morning is over, John has lunch but does not wash his hands; he has 2 g of the pesticide on his hands. Pesticide X has about 90% absorption from an oral dose.
Finally, John works in the field in the afternoon a crop plane flies over dusting the crops with pesticide X, the air he breathes in has a total of 5 grams of the compound in it. Pesticide X is known to have absorption of about 50% through inhalation.
What is John’s exposure to Pesticide X and what is his dose?
Route of Exposure Exposure (grams) Dose (grams)
Dermal
Oral
Inhalation
Total
Looking at the total exposure and dose, what percentage of his exposure was a dose?