Search  Index  Home  Glossary  Contact Us  

Step 2.1 Estimating Exposure Doses Example of an Ingestion Dose for Evaluating Noncancer Health Effects The following example involves the calculation of a noncancer dose and a cancer dose for a gardener exposed to arsenic in surface soil for 35 years where the following assumptions are made. The arsenic concentration is eleven milligrams of chemical per one kilogram
of soil. To calculate the noncancer exposure factor, multiply five days per week by twentysix weeks per year by thirtyfive years. Then divide the product by three hundred sixtyfive days per year times thirtyfive years. The noncancer exposure factor equals 0.36. Then divide the numerator by the denominator. Note: if the exposures are daily, then the exposure factor is one. To calculate the sitespecific dose, multiply eleven milligrams of chemical per kilogram of soil by 100 milligrams of soil per day by 0.000001 kilograms of soil per milligram of soil by the exposure factor of 0.36. Then divide the product by seventy kilograms, which is the body weight. The 0.000001 kilograms of soil per milligram of soil is used to convert the arsenic level from milligrams of chemical per kilogram of soil to milligrams of chemical per milligram of soil. Using this calculation, the dose is equal to 0.000006 milligrams of chemical
per kilogram of body weight per day. 
Last
updated:
February 20, 2008

ATSDR
EPH Training Coordinator 
DHAC Home 