Step 2.3 Evaluating Exposures for Possible Health Effects
Advanced Exercise
As part of the Oak Estates evaluation, the health assessor estimated the exposure dose for a person contacting Aroclor 1254 while gardening. Next, the health assessor decides whether Aroclor 1254 should be evaluated further. The health assessor’s first step is to compare the exposure dose to a health guideline.
Initial findings
The estimated exposure dose is slightly below the health guideline:
- noncancer dose equals 0.00001 milligrams of chemical per kilogram of body weight per day
- MRL equals 0.00002 milligrams of chemical per kilogram of body weight per day
Further evaluation
When evaluating possible health effects, a health assessor using the weight-of-evidence approach would want to know the following:
- MRL is based on a LOAEL from a fifty-five month study of monkeys exposed through gavage (injecting into the stomach through a tube).
- Decrease observed in antibody levels (immune system response) as a result of exposures.
- LOAEL was 0.005 milligrams of chemical per kilogram of body weight per day.
- Safety factor of three hundred was applied to LOAEL to calculate MRL.
- Aroclor 1254 is a polychlorinated biphenyl.
- Exposures in developmental stages may pose a unique hazard to children and fetuses.