Evaluating two possible solutions to immobilize drift sands in
the Sub-Aral region
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Contents
1. Introduction..................................................................................3
2. Problems......................................................................................4
 Environmental damage .......................................................4
 Health effects.......................................................................4
3. Possible solutions.........................................................................6
 Carboxymethyl cellulose, straws and the salt-resistant
plants………………………...........................................................6
 Planting the saxaul...............................................................7
4. Evaluation of possible solutions ………………………….........................8
5. Conclusion....................................................................................9
6. List of References........................................................................10
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Introduction
Once the Aral Sea was the world’s fourth-largest lake; it was famous for
its rich natural resources, and Sub-Aral flora and fauna used to be prosperous
and rich. Since the 1960s, the Aral Sea has been drying out, because its two
main rivers Amu Darya and Syr Darya have been overused for irrigation. This
has led to serious problems as large amounts of river water could not reach the
sea due to irrigation or were lost in sands. 1962 was the start for a catastrophic
drying out of the sea. Since 1962 the Aral Sea’s area reached 36 thousands
kilometres squared, that is three times smaller than at the beginning of the
1960s. Moreover, the sea level has dropped to 14m compared to that period of
time. Salinity has increased significantly as water level has decreased to 70%,
leaving approximately 2.7 million hectares of open shores (Wiggs et al, 2003,
p.142). The desiccated sea bottom has already got its name – Aralkum desert
whose surface consists of salt and mineral remnants, washed from irrigated
fields. This situation is becoming dangerous due to the location of the sea. The
Aral Sea undergoes of strong winds that predominantly blow from west to east,
and spread vast amounts of salt thousands kilometres away from the sea (Wiggs
et al, 2003, p.142).
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Figure 1. Aral Sea water level from 1989 to 2003 (TERRA satellite, NASA).
Figure 1 illustrates dramatic changes in the Aral Sea’s water levels between
1989 and 2003 taken by MODIS spectrometer from the TERRA satellite.
During this period the water level in the Aral Sea has decreased by 5 times
according to NASA estimations.
It is known that drift sands of the Sub-Aral area and Aral’s drained
bottom are over salted. The most worrying factor, which is causing
environmental damage, is drifting of salts and dust with wind from the Sub-Aral
area, which is approximately 75-100 million tonnes every year (Meshkov et al,
p.118). Consequently, it is important to find ways to fix salty sands and create
hard soil crusts, which will prevent corrosion from spreading and allow plants
to live in the Sub-Aral area. Water resistant macrostructure of the salty sands is
over 0.25mm, which is considered very small number (Ali, 2011, p.30). These
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macrostructures have a significant influence on the salt resistant plants
cultivation. Hence, planting salt-resistant plants and saxaul could prevent wind
erosion and fix drift sands. The aim of this essay is to examine two ways of
preventing drift sands in the Sub-Aral region from wind erosion. First, the use
of chemical fastening substances such as water-soluble polymer Carboxymethyl
cellulose (CMC) and straws, and planting the salt-resistant plants Agropyron
cristatum will be discussed. The second solution to the Aral problem could be
planting the saxaul.
Environmental damage
Suspended solids in the form of aerosols with agricultural pesticides,
fertilizers and other harmful components of industrial and municipal wastes
prevail in the composition of the winds. One of the dangerous consequences of
the drying out of the Aral Sea is the increasing degradation of mountainous
glaciers. Intensive melting of glaciers occurs because of the increase of dust on
glacier surfaces and mineralization of precipitation on them (Glants & Zonn,
2005, p.17). Regional climatic changes have also resulted directly from
atmospheric and ecological changes in the Aral Sea’s basin. These changes
include a reduction in rainfall and changes in regional wind flow patterns aloft
and at ground level. The reduced size of the sea surface means that the Aral Sea
was not able to moderate the harsh effects of the cold winds from Siberia or to
reduce heat extremes in the summer time. Furthermore, the growing season was
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shortened, pasture productivity cut in half and precipitation along the seashore
was reduced considerably (UNEP/GRID, 1998).
Health effects
Since the drying out took place the population health changed for the
worse in the Aral Sea Basin. The negative effects occurred because of the Aral
Sea environmental problems including water contamination, air pollution, lack
of portable water and low sanitation levels. Left behind population of the
Sub-Aral region struggled to maintain living conditions in a landscape that
suddenly turned hostile. This is an issue of the day in the Aral Sea Basin and
neighbouring regions. Throat cancer and respiratory diseases became common,
and with no reliable protein source in the absence of fish, thousands became
anaemic. Maternal and infant mortality rates in the epicentre of the Sub-Aral
zone are one of the highest in CIS countries. Decrease of life expectancy, high
rate of tuberculosis, anaemia, cancer, asthma, dysfunction of thyroid gland,
blood-, heart-, kidney- and liver-diseases cases were observed (Small et al, 2001,
p.547). This led to worsening of genofund. The situation is aggravated by
inadequate prevention measures, morbidity monitoring and inaccessibility of
necessary medicines in the Aral Sea region.
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Table 1. Concentrations of metals in children hair from the Aral Sea region (mg/kg)
Aral Sea region
Hamburg region
Lead
15
0.5
Manganese
12.3
2.0
Aluminium
20.8
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From the Table 1 it can be noted that "the lead level in the hair of the
Kazakhstani children was 30 times higher than the upper limit in hair from
children in Hamburg in West Germany" (Jensen et al, 1997, p.192).
Table 2. Concentrations of lead and cadmium in children blood from the Aral Sea region
(µg/l)
Sample Aral Sea
Lead
Cadmium
1
187
0.50
2
160
0.57
3
150
0.70
Table 2 shows that "In the erythrocytes the lead concentration was
approximately 5 times higher than in children from Stockholm in Sweden".
Swedish standards: lead - 30 medium (range 13-79); cadmium - 0.24 medium
(range 0.18-0.30) (Jensen et al, 1997, p.192).
The Aral Sea area is confronted with a crippling water crisis. The lack of
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availability of water is a particular reason for the death of the Aral Sea and for
the associated litany of negative ecologic and human health effects. Many fish
species in the sea, which were an important economic and nutritional element in
the region, have become extinct them (Glants & Zonn, 2005, p.17). Not
surprisingly, the quality of water for human consumption is poor. Those
processes that have contributed to the sea desiccation - over-irrigation and water
mismanagement - also resulted in a rise of the groundwater table, which then
have become contaminated with high levels of salts and other minerals.
Groundwater quality ranges from a minimum of 0.4 g/l total dissolved salts
(TDS) to an astounding 4-6 g/l. According to World Health Organization
(WHO), worldwide standard for water mineral content acceptable for human
consumption is 1.5 g/l TDS (Ataniyazova, 2003, p.2).
Possible solutions: Salt-resistant plants
Problems of the Aral Sea could be solved by using chemical fixing
substances. The efficiency of the chemical method depends mostly on a fixing
substance which enables particles to interconnect and work together.
Carboxymethyl cellulose (CMC) can be used as a fixing substance, or it can be
mixed with agricultural wastes (straws). Table 3 shows that the best mix of
CMC and compost is 2% and 4% of CMC combined with 7 tonnes of straws
(Ali, 2011, p.32).
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Table 3. Increase percentages for organic matter contents of treated soil (Ali, 2011, p.29).
2% of CMC with 5 ton of compost
48.78 %
4% of CMC with 5 ton of compost
63.41 %
2% of CMC with 7 ton of compost
100 %
4% of CMC with 7 ton of compost
102 %
It should also be mentioned that CMC has other positive features such as
inexpensive price (ibid, p.24) and easy access. This is due to large-capacity
manufactures of CMC, which are mostly wastes of cotton gin plants, based in
the Republic of Kazakhstan. CMC forms viscous solutions at low concentration.
Moreover, it is a bio-decomposed polymer and is made out of natural polymer –
cotton cellulose (ibid, p.24). There is also a proven example of fixing drift sands
with the use of wheat straw for the chemical composition. It is a renewable
waste, produced annually. Generally, millions tons of it are either earthed or
burnt, thus causing environmental damage.
Figure 2. Agropyron cristatum
(Retrieved from http://www.forestryimages.org/browse/detail.cfm?imgnum=1459834 )
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Agropyron cristatum (shown in Figure 2) is a crested wheat grass that represents
a species in the Grass family (Poaceae). This plant is often used for forage and
erosion control. Agropyron cristatum is a highly competitive and persistent
plant in drier areas, and has a moderate ability to spread by seed (USDA, 2006,
p.1). Using salt-resistant plants such as Agropyron cristatum will facilitate the
development of livestock; consequently, it could improve the wealth of local
people and create soil conditions for natural colonization.
According to Ali (ibid) free disperse sand system changes into viscously
disperse aggregated system because of the influence CMC complex mixture and
wheat straws. They have a positive influence on hydro-physical properties of
the soil such as diminishing soil bulk concentration and preventing macro
porosity. Thus, pores, that hold water, are growing, whereas the mean diameter
of soil pores is lessening causing soil to preserve more moisture. This is also
called hydraulic conductivity. Moreover, the cure applied on soil chemical
assets resulted in minor shrink of soil pH and raise of organic content. An
increase in soil nutrient substances such as nitrogen, phosphorus and potassium
was also noted (Ali, 2011, p.23).
Planting the saxaul
The ecosystem of saxaul pastures, that were the richest in biological
productivity of the Aral Sea, have undergone human negative impact in recent
years. In 90’s felling saxaul for heating needs by the local population became an
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issue as created a threat of a complete destruction of the Haloxylon aphyllum
(saxaul) and Haloxylon persicum ecosystems. As a result, 60% of the saxaul
region is experiencing a severe degradation process (Orlovsky, Birnbaum, 2002,
p.234). Excessive felling of trees and shrubs in the area of runoff formation
resulted in the increase of negative processes such as floods, mudflows,
landslides, lack of water.
Figure 3. Saxaul
(Retrieved from http://www.plantarium.ru/page/image/id/40287.html)
Saxaul tree (shown in Figure 3) is spongy and absorbs moisture through the
bark, so the water can be extracted, which is a critically important commodity
for people of the deserts. Saxaul also supplies cover and forage for wildlife, for
instance, camels, sheep and various bird species (ibid, p.235, 239). Saxaul is
used in medicine as an antidote and also as a cure for gastrointestinal-tract
diseases (Baisalova, Erkasov, 2011, p.1). Saxaul forest regions which are
located near urban areas, is predicted to be a source of income for farmers and a
source of additional supplies of wood. However, there is a great risk that
planted saxaul will be used by the local population as a fuel source due to the
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fact that the city has not developed a gas network yet.
The activities of afforestation, planting, care and development of forest
resources could increase the employment of local population, which is one of
the main benefits. Hence, this might also result in the income increase of local
people. The new shrubs, bushes, and plants capture rain and snow that are
crucial in the drought-affected Aral region whose current annual precipitation
averages only 150-200 millimeters (UNEP/GRID, 1998). Saxaul has a deep and
well-developed root system. The roots of the plant grow parallel to the ground
and fasten to the mixture of sand, dust and salt. Thus, saxaul prevents further
erosion and is capable of absorbing water from soils with very low moisture
content, while the upper part of the plant acts as a windbreaker, decreasing wind
velocity (Orlovsky, Birnbaum, 2002, p.235).
Evaluation of possible solutions
There is no lack of saxaul seeds in Kazakhstan and the zone of saxaul
forests occupies almost 50% of the Republic’s territory and has an area of 10.17
million hectares (Orlovsky, Birnbaum, 2002, p.234). One of the advantages of
saxaul is that once it is planted, it will be there for years. Moreover, it is a
reasonably fast growing species and particularly rapid growth is noted in its root
system, which, in 3 years, reaches up to 5 meters deep and can penetrate 10
meters into the ground. CMC polymer is bio-decomposed polymer, and since
the Republic of Kazakhstan has obtained large-capacity manufactures of CMC,
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it is inexpensive and easily accessible (Ali, 2011, p.24). However, the CMC
factories are located 300 kilometres away from the Aral Sea. Therefore,
transport costs are needed in order to send the polymer to the Sub-Aral region,
which could significantly add to the cost of the product. Thus, using seeds and
planting saxaul could be much cheaper than using CMC.
Using the CMC polymer with wheat straws and salt-resistant plant as
well as planting saxaul appear to be the best possible solutions to immobilize
drift sands in the Sub-Aral region. These methods create hard soil crusts that
will not prevent plants from growing, but prevent corrosion from spreading.
Consequently, the number of dust storms will decrease, so population health
will change for the better as air pollution is predicted to reduce. Biological
productivity of arid areas will increase and finally the climate change could
become sustainable and heat extremes in the summer time may be reduced.
From the research it can be seen that both solutions have only positive effects
on the environment (Orlovsky, Birnbaum, 2002, p.235).
The activities of afforestation, planting, care and development of forest
resources will increase the employment of local population, which is one of the
main benefits. Moreover, the plants may also provide an alternative fodder
source for animal production, thereby increasing agricultural productivity. In
other words, both solutions will increase employment as well as the wealth of
local residents.
In this essay two possible solutions were compared in terms of the
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following aspects: cost, environmental effects and employment. From the
environmental side, both solutions show only positive effects. They are
ecologically-friendly and the common feature of Agropyron cristatum and
saxaul plants is their high adaptability to adverse climatic conditions such as hot
dry summers, cold winters, low humidity and shifting sands. Furthermore,
implantation of these plants will require labour force. Hence, employment of
people in the Sub-Aral region will increase their prosperity and possibly the
standard of living will rise. However, expenses related to the application of
these methods differ. As for saxaul the only thing that is needed is seeds,
whereas for CMC and wheat straws transportation to the Aral Sea is required.
Therefore, from the research it can be seen that it is cheaper to use saxaul than
CMC water-soluble polymer and wheat straws.
Conclusion
Two methods of preventing the eolation process of sand dust aerosol
drifting were examined. The first method is based on using chemical fastening
substances, consisting of a CMC water-soluble polymer and wheat straws as
well as the planting of the salt-resistant plant agropyron cristatum. The second
technique studied is the planting of saxaul. The former method is a chemical
way to fix drift sands of the Aral Sea with the help of complex additives,
consisting of a CMC with agricultural wastes – wheat straws, preventing
corrosion and helping to improve ecological conditions in planted areas of the
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Sub-Aral and in the Aral Sea’s drained bottoms. This has two positive features
such as solving ecological problems and waste utilization. Similarly, planting
the saxaul in the Sub-Aral region will contribute to solving important social and
environmental issues. This will result in the reconstruction of the past forage
base for livestock and fixing large areas of the dried bottom. The elimination of
the hearts of salt and dust removal will improve the environmental situation at
the local and regional levels. Appearance of a stable vegetation cover will create
a kindly micro-climate and soil conditions for natural colonization. All in all,
immobilizing drift sands in the Sub-Aral area by planting saxaul is considered
to be the most suitable and the cheapest way.
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