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

 6.3.2.  Effects of environmental pollutants and factors on 
human beings
Pollutant chemicals and biological factors (living organisms) 
might be present in the air, water, soil and food, and they can enter 
the body through the respiratory tract, gastrointestinal tract, skin, 
eye conjunctiva and placenta. The ways of entry depend on the 

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6. Action of toxic substances in the environment – basic concepts of ecotoxicology 
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aggregative state of substances and physical and chemical properties 
of compounds. Whatever the mode of absorption, all chemical 
substances enter the bloodstream and, from there, into various 
organs and tissues.
Bacteriologically contaminated water is the main cause of 
the diseases of the digestive system, skin, eyes and many other. 
Approximately  80%  of  diseases  recorded  on  a  global  scale  and 
more than a third of death occurrences in developing countries are 
directly related to the use of contaminated water.
The most representative physical pollutants of the environ ment 
are noise, vibration, non-ionising and ionising electro magnetic 
radiation.
The action of pollutants mostly affects those organs and systems 
that perform the barrier functions on the boundary between the 
environ ment and organism, preserving the organism’s internal 
environ ment  uncontaminated.
Diseases can develop from the effects of pollutants due to human 
susceptibility. Although the pathogenic effect always depends on the 
intensity and duration of exposure, persons who are more susceptible 
to diseases may fall ill even after a minor contact with a hazardous 
factor. Susceptibility depends on the biological factors (age, sex, 
heredity, other diseases), lifestyle (dietary regime, smoking, alcohol, 
stress), change of the environ ment if it was different in the previous 
place of residence or work. 
Differences in susceptibility decrease with increasing exposure – 
in extremely hazardous conditions, both more susceptible and less 
susceptible persons may become ill. Children and the elderly are 
more sensitive to environ mental pollutants.