2.3 Evaluating Exposures for Possible Health Effects
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
The estimated exposure dose is close in value to the health guideline,
although it is slightly lower.
The estimated exposure dose for noncancer health effects is 0.00001 milligrams of chemical per kilogram of body weight per day for an adult at Oak Estates exposed to Aroclor 1254 while gardening.
The minimal risk level is 0.00002 milligrams of chemical per kilogram
of body weight per day.
Because the estimated dose is the same order of magnitude as the health
guideline, the health assessor will likely further evaluate the exposure.
When further evaluating health effects that could result from exposure,
a health assessor using the health effects evaluation approach would want to
know the following information about existing studies that might be considered
in the evaluation.
The minimal risk level is based on a lowest-observed-adverse-effect-level
from a fifty-five month study of monkeys exposed through gavage (a procedure
in which chemicals are injected into the stomach through a tube).
A decrease was observed in antibody levels (immune system response) as
a result of exposure.
The lowest-observed-adverse-effect-level was 0.005 milligrams of chemical
per kilogram of body weight per day.
A safety factor of three hundred was applied to the lowest-observed-adverse-effect-level
to calculate the minimal risk level.
Aroclor 1254 is a polychlorinated biphenyl.
Exposure to polychlorinated biphenyls may pose a unique hazard to children