||This is the
first of a three-part lecture characterizing the toxicity,
bioaccumulation, and persistence properties of environmental endocrine
disruptors (EEDs). The characterization is primarily from a health risk
assessment perspective. Therefore, the effects and properties so
characterized are mainly those pertinent to exposure and risk significance,
rather than those dealing with adverse health effects, of which endocrine
disruption is an important type. The lecture’s overall objective is to
convey the concept that even for a short duration, exposure to a persistent
bioaccumulative EED of low disruption potency could lead to a severe health
To facilitate the characterization so promised, this Part I
presents an overview of the human endocrine system and the basic mechanisms
of endocrine disruption. It then concludes with a literature review to
ascertain the effects of endocrine disruption as a major health problem.
reviews the factors fundamental to a substance’s fate and bioaccumulation in
the environment. Another effort of Part II is to provide some evidence from
the literature on bioaccumulation and long-range transport. These literature
data are intended to support the asseveration that many endocrine disruptors
are highly bioaccumulative.
brings forth the main themes of this lecture. It illustrates how and why
endocrine disruption is inducible from exposure to a persistent
bioaccumulant, even when its disruption potency is low and the exposure
duration is short. Part III further elucidates the notion that at times,
even induction of this kind could end with a severe health outcome.