Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

Table 6.3. 
Substances with estrogenic activity and their typical 
concentrations in the environment 
Substance
Concentration
Environment
Estrone
(1.4-76) × 10
–9 
g/l Wastewater
Oestradiol
(2.7-48) × 10
–9 
g/l Wastewater
Nonylphenol
(0.15-2.8) × 10
–6 
g/l  Wastewater
Pthalic acid esters
3.2 × 10
–6 
g/l  Gull eggs
Polychlorinated biphenyls (PCBs)
14.1 × 10
–3 
g/kg  Wastewater
Food may be considered to be the major source of intake of 
substances  affecting  the  endocrine  system:  food  products  that 
contain these substances, food additives and food packaging.
Endocrine  system  regulation  disorders,  in  turn,  can  affect 
the central nervous and immune system. These disorders may 
occur already in the embryonic development stage, and they can 
cause sexual behaviour changes, slowdown in the development 
of secondary sexual characteristics, prostate disorders, decrease 
in sperm production and sexual activity, reproductive function 
disorders, male feminisation, formation of malignant tumours.
Environmental estrogens, 
acting on living 
organisms,
 
Œ simulate the action of 
estrogen synthesised 
in the body. The 
substances affecting 
the endocrine 
system are capable 
of producing effects 
similar to those caused 
by endogenous 
steroids.
 
Œ block, eliminate or 
modify the bonding of 
hormones with their 
receptors, thereby 
affecting the quantity 
of hormones and type 
of effect on the cell. 
Such substances are 
called anti‑estrogens or 
anti‑androgens;
 
Œ alter the rate of 
production or decay 
of naturally formed 
hormones;
 
Œ affect the structure of 
hormone receptors or 
their formation in the 
body.

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112 
ENVIRONMENT, POLLUTION, DEVELOPMENT:  THE CASE OF UZBEKISTAN
The thyroid gland is particularly susceptible to the adverse 
effects  of  environ mental  factors.  Studies  show  that  elevated 
concentrations of heavy metals – lead, manganese and mercury – in 
the environ ment cause pathological changes in the thyroid gland.
The proven effects of substances that affect the endocrine system 
manifest themselves in the form of reproductive system abnormalities 
and development delays. These effects have been proved by both labo-
ratory studies and cases when these substances entered the environ-
ment, affecting the development of living organisms. It is believed 
that these substances contribute to malignant tumour development. 
For example, diethylstilboestrol was used as a medication to reduce 
premature birth risk, and a considerable increase in the cancer 
mortality rate in the daughters of women who used this medication 
was proven only much later. From the ecotoxicological point of view, 
the impact on wild animal populations has been acknowledged as