Environmental Engineering Reference
In-Depth Information
7
ENDOCRINE DISRUPTOR CHEMICALS
The human endocrine system consists of a set of ductless glands such as
the thyroid, adrenal glands, pituitary body, and gonads that secrete different
hormones to regulate physiology. Hormones secreted by these are able to
effectively regulate a host of body functions including growth and
reproduction. Each hormone is very specific as to its function and acts on
a single target cell or tissue. These affect the physiology by interacting with
receptors on the cells (including serotonin, dopamine, norepinephrine
receptors in addition to the hormone receptors) and controlling the
intracellular physiology and function (Pickering and Sumpter, 2003).
Natural hormones, including estrogens, androgens, progesterone, thyroid
hormones, as well as hypothalamic and pituitary hormones, are present in
very low concentrations in the body. But they provide a critical role
coordinating growth, metabolism, and reproductive processes in the body.
the functioning of the endocrine system leading to adverse health impacts.
Nearly a thousand of man-made chemicals released into the environment are
recognized as EDCs (Vandenberg et al., 2009). Some of these, structurally
similar to hormones, interact with relevant cell receptors to confuse the
body's physiology. They either mimic or antagonize the effects of the 50 or
so hormones. Others prevent the hormone-receptor interaction or interfere
with hormone synthesis itself, disrupting endocrine function. EDCs typically
have molecular weights less than 600 Da and like hormones are effective at
very low concentrations. Most have an aromatic ring especially with phenol
functionalities in their structure and are sufficiently hydrophobic to interact
with the biological receptors.
The presence of EDCs in the body affects functions such as metabolic and
reproductive processes including embryonic development, gonadal
formation, sex differentiation, growth, and digestion. They are plausibly
linked to diseases including prostate cancer, breast cancer, attention deficit/
hyperactivity disorder (ADHD), asthma, and reproductive problems (Myers
et al., 2009; Swan et al., 2000). Though not toxins in the conventional sense,
