Threat by chemical substances: Legislation, production, use and waste - Environmental Deterioration and Contamination: Problems and their Management - page 64

endocrine-active chemicals could affect sperm quality. But so far, no research
has studied the direct relationship between exposure to endocrine disrupting
chemicals and sperm quality;

◦ Fertility : Some human and experimental animal studies have shown that occu-

pational or environmental exposure to high levels of certain chemicals such as
pesticides and PCBs can impair fertility and increase the rate of miscarriages;

◦ Sex ratio : In a number of regions and countries, fewer boys than girls are

being born in spite of the “biological rule'' that more males “should'' be born
to balance higher rate lethality of males. Whether EDs are involved is not
clearly proven;

Abnormalities of male sex organs : Increased numbers of birth defects in male
sex organs have been reported. The abnormalities are cryptorchidism, a condi-
tion in which the testes remain inside the abdominal area instead of descending
into the scrotum. Another disorder is hypospadias, which is a malformation
where the opening is on the underside of the penis instead of at the end.
Experimental animal studies clearly show that a number of EDs can disrupt
development of the male reproductive system;
- Endometriosis is a disease affecting women where uterine tissue appears in parts
of the abdomen other than the uterus, causing pain and infertility. The disease is
made worse by estrogens. Some reports have linked development of endometriosis
in women exposed to EDs, such as dioxins;
- Precocious puberty : Some studies have raised concerns about the possible influ-
ence of EDs on the timing of puberty, or the process of sexual maturation.
There is evidence from population studies that the age at which puberty normally
occurs is becoming younger, but there is no scientific evidence on the role of EDs
in this;
- Cancer : We know that some types of cancers are “hormonally sensitive.'' The most
concerned cancers are endometrial, breast, testicular, prostate and thyroid.

◦

The definitely decreased fertility and increased reproductive abnormalities in
human population and wildlife may be evidences on the adverse effect and high risk of
EDs. The pesticide atrazine, one of the most widely used farm pesticides world-wide,
has feminized male frogs and other animals in several scientific studies. But research
examining potential effects in people is relatively sparse. This may be the reason for the
still existing debate between positive scientific results (e.g., Hayes, 2004) and negative
industry opinion.
Hormone disruption may be associated with the development of cancers in
hormone-sensitive tissues and with the epidemic scale obesity (Karoutsou & Polymeris,
2012). Endocrine disruptors being responsible for obesity are also called obesogens.
The study of García-Mayor (2012) reviewed the available evidence about potential obe-
sogens in humans such as diethylstilbestrol (DES), bisphenol A, organotins (TBT, TPT),
and phthalates. DES and Bisphenol A mainly act upon estrogen receptors, while organ-
otins and phthalates activate PPAR , the peroxisome proliferator-activated receptor

gamma or glitazone receptor mostly found in adipose tissue and the intestine.
Studies conducted on lab mice show that the animals which were exposed to
organotins such as tributylin (TBT) or triphenyltin (TPT) were more prone to develop

γ