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.

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