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.