184
ENVIRONMENT, POLLUTION, DEVELOPMENT: THE CASE OF UZBEKISTAN
molluscs – dangerous for consumers, as it is shown that many
species of molluscs in their bodies accumulate significant amounts
of pathogenic viruses. It is believed that in a number
of cases
contaminated edible molluscs have caused localized epidemics of
infectious hepatitis.
Of the industrial companies, the largest biological contamination
in seas and oceans is created by insufficiently treated waste water
from paper mills, sugar mills, meat processing and other food
production companies, containing large
amounts of organic sub-
stances subject to fermentation processes. In these processes, large
amounts of oxygen are consumed,
water turbidity increases, and it
has a very negative overall impact on aquatic organisms.
At major rivers water mass contamination is increasing down-
stream. Estuarines of Syr Darya and Amu Darya are characterized
by increased index of water contamination over last years, however,
river pollution during last years, is decreasing.
Exceeding the permitted usage of
agrochemicals results in a
high level of contamination of agricultural land and water resources.
Industrial production is contaminating water with mainly heavy
metals, phenolics and petroleum products. Industrial, household
and municipal, manifold and drainage waters, discharged
in rivers,
contain many pollutants, concentration of which in average is
2-10 times greater than permissible concentrations for household
and drinking needs, and also fishery needs. The volumes of
contami nated waters of household discharged into rivers have been
decreasing over the last years. However, the degree of purification is
not sufficiently high. Low effectiveness of water treatment facilities
(50-70% from set capacities) is a reason
for high concentration of
pollutants, discharged in surface waters and drops in the area. After
purification waste waters have elevated concentrations of ammonia
ions and nitrites. A particularly difficult situation is observed
in regions with a deficit of water resources (Karakalpakstan,
Khorezm, Buchara) and in regions with a high concentration of
industrial output (Tashkent, Fergan, Samarkand, Navoji industrial
districts). Approximately 1-5% of the water used in industry is
discharged without purification. Most rivers of the region in their
lower and middle streams have an increased water mineralization:
from 1-1.5 g/l – in the middle stream, up to 2 g/l and more in
lower stream. In the lower reaches of river Amu Darya an excess
in mineralization and water hardness, also in sulfates, chlorides,
phenolics and silica is permanently recorded. Water contamination
with mercury and fluoride is approaching limit values.
The main water arteries of the Uzbekistan became almost unfit
for the drinking water supply due to absence of
systematic fresh water
releases and discharges of waste water in river from irrigated soils
Sources of water pollu‑
tion in Uzbekistan are:
contamination as a
result of agricultural
activity;
contamination as a
result of industrial
activity;
contamination with
household and
municipal waste in
urban and rural regions.
8.
WATER POLLUTION
185
with excessive mineralization, polluted with pesticides and mineral
fertilizers. The provision of the population with fresh drinking water
is particularly important. Consequently, in Karakalpakstan fresh
water supply is, on the average, 61.5%, while in Berunijskij region –
36.3%, in Shumanijskij – 32.5%, in Amudarjinskij – 28.7%. In total,
more than a third of population of the country is consuming an
insufficient amount of fresh water according to the state standard.
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