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

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6. ACTION OF TOXIC SUBSTANCES 
IN THE ENVIRONMENT –  
BASIC CONCEPTS OF ECOTOXICOLOGY
 6.1. 
 Concept of ecotoxicology
The existence and development of humankind has become depen-
dent on the quantity of chemical substances that are used in various 
pro duc tion processes and households. Substances essential for every-
one are polymers, plant protection agents and pharmaceuticals. They 
are used in clothing manufacture, construction, agriculture, house-
hold, and their use has made it possible to improve the human life 
quality and to extend the lifespan significantly. We can argue that 
the production of any chemical substance is associated with both the 
bene fits from its use and the risk that may be caused by its adverse 
pro perties. Human health can be affected not only by the use of che-
mi cals but also by various physical factors, such as electro magne-
tic radiation, noise and heat. The electro magnetic radiation of high 
energy and short wavelength (γ-radiation) can destroy the structure 
of cells, influence the biomolecules which determine reactions taking 
place in the body. Therefore, exposure to high doses of this radiation 
is lethal to humans. Electro magnetic radiation of longer wavelengths 
(200-400  nm)  (ultraviolet  radiation)  can  cause  skin  pigmentation 
(tanning), but lasting exposure to this radiation can promote skin 
cancer. Another physical factor of environ mental pollution – noise – 
can cause discomfort, earache or hearing impairment; prolonged 
exposure can affect a person’s mental health. Living organisms (bio-
lo gical environ mental pollution) can also affect human health and 
ecosystems.
Consequently, an increasingly urgent need arises to assess the 
effects of substances and different factors on people who produce and 
use them as well as other living organisms and their communities – 
ecosystems, and to forecast their content in the natural environ ment 
in the future and to estimate their concentrations.
Figure 6.1. 
Laboratory 
animals are a common 
test object to evaluate 
toxicity of chemical 
substances

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