THE
INTERNATIONAL PROJECT ėNAVRUZî IN KAZAKHSTAN.
RESULTS
OF INVESTIGATIONS FOR THE PERIOD OF
FALL
2003 - SPRING 2004
K.K.
Kadyrzhanov,
V.P. Solodukhin, S. Khazhekber, V.L.
Poznyak,
H.D. Passell*,
G.M.
Kabirova,
V.V. Smetannikov, R.M. Gabdulin, E.E.
Chernykh,
A.D.Musrepov, A.S.
Liventsova
Institute of Nuclear Physics NNC,
Ibragimov St. 1, Almaty-32, Republic of Kazakhstan, solodukhin@inp.kz.
*Sandia National Laboratories,
P.O. Box 5800 MS 1373, Albuquerque, NM 87185-1373, USA.
The main
purpose of the project ėNavruzî is research and monitoring of radiation and
ecological situation in basins of main rivers of Central Asia -- the Syrdariya
and the Amudariya in the territories of Kirghizia, Uzbekistan, Tajikistan and
Kazakhstan [1-3].
Of those two rivers, only the Syrdariya and its tributaries flow through
Kazakhstan. The present work presents main investigation results of this river
basin during the period from fall 2003 to spring 2004 (correspondingly 5th
and 6th expeditions).
Figure
1. The scheme of sample points.
Expedition
works were carried out according to the layout presented in Fig.1. Monitoring
of water and bottom sediments was carried out at 15 permanent control points
from KZ 1 to KZ
15. With a
view of more intensive investigation of radiation and ecological situation
there was carried out sampling of soil, water and bottom sediments at the following
additional control points: expedition 5 (KZR 16-30); expedition 6 (KZR 16, 17, 20, 25, 26, 28-40). In the
course of expedition works there were determined main chemical-physical
parameters of water with the help of "Hydrolab" device: temperature t, С; specific
conductivity Ec, mСm/сm; total
quantity of dissolved substances TDS, g/l; рН level; reductive-oxidative
potential ORP,
mV. Prior to
sample analysis, water was filtered through membrane filters with 20mm pore. Filters were dried and
incinerated in the laboratory environment. Filtered water was fully evaporated.
After preparation, samples of soil, bottom sediments, water suspended sediment component
(WS) and water-dissolved
component (WD), were analyzed by the method of instrumental gamma-spectrometric
analysis (radionuclide analysis), as well as by NAA and XRF methods (element
analysis). All
methods, used in field works and laboratory investigations, are presented in
work [4] in detail.
On the
basis of all obtained data there is determined that average content of 238U
in soil of the Syrdariya River basin comprises 2.4 mg (29.5 Bq/kg), and 232Th
is 9.1mg/g
(37.3 Bq/kg). These values evidently exceed average values of
uranium concentrations (1mg/g) and
thorium (6mg/g)
for soils of the whole world [5]. Such conclusion spreads, indeed, to all daughter
radioactive and decay products of these elements. Distribution variety of
overwhelming majority of studied radionuclides (238U, 234Th,
226Ra, 214Pb, 214Bi; 232Th, 228Ac,
224Ra, 212Pb,
212Bi; 208Tl; 235U; 40K) is
relatively low by area and depth of soil stratum at all investigated
territories. 210Pb
and artificial radionuclide 137Cs are exceptions that for the
most part concentrated in upper soil stratum and distributed more contrasting
by area. On the basis of data obtained by NAA and XRF methods there is also
determined that high contents of Na, K, Ca, Zn, and As are characteristic for investigated territory
soils. High concentrations of Sc, Br, Sr, Pb were revealed at various sites.
Radionuclide and element composition of bottom sediments corresponds to the
soil composition very largely. One can observe that average value of 210Pb
concentration, especially, of 137Cs in bottom sediments is noticeably
low than in soil. The highest concentrations in soil of natural radionuclides
of 238U
family were revealed at the border adjacent to Uzbekistan (KZR16); near uranium deposit
ėZarechnoeî
(KZR18, 19, 20); near uranium deposit ėKaramurunî of Shyili town (KZ 8, 9, 10); in the outlet of the Arys
river and downstream of the Syrdariya River (KZR 22, 23, 24); in
Kurkeles riverbed (KZR 30); at vicinities of Qyzylorda city and downstream of the
Syrdariya (KZ
11, 12; KZR 26). The most high concentrations of natural radionuclides
of 232Th family
were also revealed at the
border adjacent to Uzbekistan (KZR-16); near ėKaramurunî deposit (KZ 8, 9, 10); in
Syrdariya riverbed, down Qyzylorda town (KZ 12, 13), at vicinities of Arys
river confluence (KZR 23, 24, 35), in Keles (KZ 3, 4; KZR-17) and
Kurkeles riverbeds (KZR-30). The most 137Cs concentrations were revealed at
sites (KZR
22, 23) located most closely to the underground nuclear explosion ėMeridian-3î.
At present there is carried out more detailed investigation at vicinities of
this explosion. High concentrations of microelements in soil were revealed at
vicinities of large cities as Shymkent at the Badam River (Cr, Zn, As, Sb, Pb); Saryagash
at the Keles River (Cr, Zn, Br, Sb, Ba); Qyzylorda at the Syrdariya River (Cr, Zn, Br, Sr, Sb). High
concentrations of Br (15-20mg/g), Sr (up to 500mg/g) and Zn (up to 140mg/g) were
revealed near ėZarechnoeî deposit (KZR-20). In the area of ėKaramurunî deposit (KZ 8, 9, 10) there were
revealed high concentrations of Fe, Zn, Sr, Ba, Pb as well.
The
average value for рН in the Syrdariya and its tributaries was 8.0ą0.2, and reductive-oxidative potential
(ORP) was 400ą40 mV. During the expeditions a change of Ec
and TDS value was revealed in headwaters of the Syrdariya river, where its
tributaries exerts a considerable influence. Especially, it is determined that
waters of the Keles and Kurkeles rivers are characterized by high
physical-and-chemical indicators: TDS up to 2.6 g/l, Ec up to 4000 mSm/cm. Down the last tributary
(the Arys river) there were no seasonal changes determined in values of these
parameters. On this run of the Syrdariya river average value for Ec
is (1620ą80) mSm/cm and for TDS is (1.04ą0.05) g/l.
According
to the investigation results of the elemental composition there were revealed
high concentrations of Cr, Fe, Co, Ni, Zn, As, La, Ce, Th in bottom sediments
of headwaters of the Syrdariya river (above the Shardara reservoir). One can
suppose that these microelements come with waters of Keles and Kurkeles
tributaries. Specifically, it is determined that concentrations of these
microelements in outlet water of the Keles river exceed their average values
for the Syrdariya river by 5-8 times. In water of the Kurkeles river there were
revealed maximal concentrations of Se at 5.9 mg/l, Sr at 6.8 mg/l and U at 35.5 mg/l.
Maximum
concentrations for the majority of microelements in water of the Syrdariya
river occurs near Kyzylorda city and Terenozek, Zhusaly towns. Most probably it
is connected with hydrological peculiarities of this river.
A high
concentration of Ca, Zn, As, Se, Re and other elements has been revealed in
waters of the Badam and Arys rivers. Especially, the composition of Re (up to 1.8
mg/l) in these waters
exceeds its average value in the Syrdariya river (0.08) more than 20 times. The
revealed feature is probably related to industrial activity of Shymkent city.
The
obtained results argue that concentrations of many elements along the Syrdariya
River essentially exceed (by 10 to 100 times) corresponding world average
values. Especially, average 238U concentration equal to 17.7mg/l (218mBq/l) exceeds
world average value (1 mg/l) by almost
20 times. Thorium concentration in water of this river is higher than world
average value by 15 times. Fe concentration in water of the Syrdariya River,
practically along the whole length of it, essentially exceeds (by several
times) the sanitary norm of maximum permissible concentrations for drinking
water.
References
1. Barber
D.S., et al. (2002) Radioecological situation in the river basins of Central
Asia, Syrdariya and Amu-Daria: on the results of the International project
"Navruz", Environmental Protection Against Radioactive Pollution, Almaty,
Republic of Kazakhstan, 84-86
2. Barber
D.S., et al. (2003) The Navruz experiment: cooperative monitoring for
radionuclides and metals in Central Asia transboundary rivers, MARC-VI,
Kailua-Kona, Hawaii, USA, 111.
3. Kadyrzhanov
K.K. et al. (2004) Research and monitoring of radiation and ecological
situation in Syrdariya river basin at the territory of republic of Kazakhstan
(International project "Navruz"), Monitoring of migration and
accumulation of radionuclides in component of natural ecosystems, OSCE,
Dushanbe, 70-81.
4. Solodukhin
V.P., et al. (2004) Some peculiarities of the contamination with radionuclides
and toxic elements of Syrdariya river basin, Kazakhstan, Journal of
Radioanalytical and Nuclear Chemistry, Vol. 259, №2,
245-250.
5.
Vinogradov A.P. (1957) Geochemistry of rare and
scattered chemical elements, Moscow, 338 p (in Russian).