Chemistry for Sustainable Development 12 (2004) 553564 553 Heavy Metals as Status Indicators for the Ob River S. V. TEMEREV and V. M. SAVKIN 1Altay State University, Pr. Lenina 61, Barnaul 656099 (Russia) E-mail: [email protected] 2Institute of Water and Environment Problems, Siberian Branch of the Russian Academy of Sciences, Ul. Molodezhnaya 1, Barnaul 656038 (Russia) E-mail: [email protected] (Received July 8, 2003; in revised form November 6, 2003) Abstract This paper presents a comparative analysis of the contents of heavy metals (HM) in the water, suspended matter (SM), and bottom sediments (BS) of the Ob river based on the results of long-term monitoring. The spatial distribution of metals along the middle and lower course of the Ob river is affected by its large tributaries such as Tom, Chulym, and Irtysh and by the Novosibirsk reservoir, as well as by large cities (Novosibirsk, Tomsk, and Nizhnevartovsk). The metal distribution at the interface between water and bottom sediments depends on the hydrological and hydrochemical conditions and is the major factor that is responsible for the higher contents of heavy metals in the bottom sediments of the Novosibirsk reservoir compared with the channel and still water lines of the river. The calculated concentration factors depend on the nature of the metal; the least factors were obtained for lead and zinc. Previous data obtained for the Ob reservoir and the upper Ob in general are discussed. INTRODUCTION sh, and Kulunda steppes. The steppe plains form a system of flat and generally cutoff inter- The Ob-Irtysh basin occupies vast territo- fluves with numerous lakes of which Chany ries in western Siberia, western Kazakhstan and the Kulunda lake are the largest. region, and northeastern provinces of China. The mountainous regions (222.1 thousand The drainage area of the Ob river is ~3000 km2) and tundra (199.6 thousand km2) are thousand km2, of which 49 % is forest. In the comparable in the drainage area, but the water forest zone, the surface slope is insignificant, resources of the tundra territories are the runoff is hindered, and the interfluves approximately five times larger. The mountain- are strongly waterlogged; especially vast marsh ous and tundra zones have differences in regions are found between the Ob and Irtysh, precipitations, but their common feature is and also in the Vasyugan region. large contributions from inlet glaciers and flood 8orest-steppe covers vast plains in south- flows resulting from fast melting of snow and western Siberia and partly in northern Ka- snowfields in the former case and spring flood zakhstan, amounting to ~404.6 thousand km2 in the latter [1]. and including the Tobol, Ishim, Barabinsk, and Ob forest-steppes. The overland runoff is in- PROBLEM ORMULATION significant because many small rivers nearly dry up in summer and freeze up in winter. The quality of natural waters is often dic- The steppe zone occupies about 707.2 thou- tated by the presence of hazardous substances sand km2 and includes the southwestern part in river waters, but not by the amount of of the Ob Plateau and Kustanay, Ishim, Irty- sludge liquor or sediment runoff. Most water 554 S. V. TEMEREV and V. M. SAVKIN 8ig. 1. Skeleton map: 113 test section lines for hydrochemical monitoring. intake systems in large cities of Siberia (No- Small tributaries such as Ulba (Ust-Ka- vosibirsk, Kemerovo, Tomsk, Barnaul) use riv- menogorsk), Aley, Barnaulka (Barnaul), Inya er (sometimes, artesian) water for water prep- (Novosibirsk), and Ushayka (Tomsk) join the aration. The quality of water in a large river Ob and Irtysh Rivers and their large tributar- such as the Ob is determined by the natural ies at different points; although their water and anthropogenic factors. One of the natural content is low, they are subject to a consider- factors is the large drainage area with a diver- able anthropogenic load, especially during sity of natural complexes. Among anthropo- spring flood. genic factors are sources of pollution at enter- The aim of the present work is compara- prises of coal and oil producers and refineries, tive analysis of water monitoring data for the and large coal and oil production centers: Nizh- Ob river within the main groups of chemical nevartovsk, Surgut, and Khanty-Mansiysk sit- pollutants (heavy metals and organic substanc- uated downstream [1]. There are metallurgical es) using the results of our own studies (1992 works of the Ore Altay (East Kazakhstan re- 2002, the middle and lower Ob) and litera- gion) located along the upper course of the ture data. Irtysh, and ore manifestations of copper, sil- ver, and complex ores are found along the upper reaches of the Aley nd Charysh rivers. PROCEDURE In the upper Ob, the quality of water is strongly affected by the Novosibirsk reservoir. The river bottom was echosounded at test In the middle course of the river, the Tom section lines (8ig. 1), and hydrometric investi- and Chulym tributaries change the quality of gations were carried out using three velocity water. Large tributaries such as Ket, Vasyu- verticals and three horizons with concomitant gan, Tym, and Irtysh carry chemical waste- sampling of water, suspension, and bottom waters in the lower portions of the Ob river. sediments (BS). The sludge liquor and sediment HEAVY METALS AS STATUS INDICATORS OR THE OB RIVER 555 runoff were calculated from the flow rate. The the data (19891991) of the Institute of Wa- integrated hydrochemical characteristics: pH, ter and Environmental Problems, SB RAS Eh, conductivity, oxygen solute (biochemical (IWEP SB RAS), permanganate oxidizability oxygen demand BOD5) and the total content (PO) in the rivers of the Katun basin was of organic matter were monitored concurrent- 0.51.3 mg of O/l, bichromate oxidizability ly. In the water samples, the total hydrochem- (chemical oxygen minimum, COM) was 10 ical characteristics were determined directly at 15 mg of O/l, and the biochemical oxygen de- the sampling site; pH, Eh, and O2 were mea- mand (BOD5) was 0.31.8 mg of O/l. The hy- sured using a Multilane 4 field multimeter drochemical characteristics were liable to hy- equi pped with CellOx 325 and SenTix 41-3 drological seasonal fluctuations. During the sum- (Germany) immersion sensors. At test river sta- mer floods, overall mineralization increased tions in still-water riverside regions of the Ob, consistently with the fluid and solid runoffs; additional samples of bottom sediments were low water runoff in summer and autumn led taken in 1999 and 2001 from depths of 40 to increased concentrations of organic substances. 100 cm. Based on O. A. Alekins concept [8] that PO is The Cu, Pb, Cd, and Zn contents in natu- the concentration of readily oxidizable or- ral water were determined under laboratory ganic substances and that COM is the content conditions by atomic absorption spectrometry of hardly oxidizable organic matter, one can with electrothermal atomization (AAS 30 ETA) state that the headwaters of the Ob have low or by inversion voltammetry (TA-2 computer- or medium contents of organic substances. ized volt-ampere analyzer, Tekhnoanalit, Tomsk Systematic hydrochemical studies on the riv- Polytechnical University, Tomsk). Analysis for er segment from Biysk to Kamen-na-Obi have heavy metals (HM: 8e, Mn, Cu, Pb, Cd, Zn) not been conducted. The data available include in bottom sediments, core samples (sectioning), scanty information about the impact of the and suspensions was carried out after wet air city of Barnaul (Altay State University, IWEP, oxidation by atomic absorption spectrometry Sanitary and Epidemiological Inspection). These (AAS 1N). Organic matter, phenols, and oil data indicate that the general hydrochemical hydrocarbons were determined by the stan- characteristics are stable throughout all hydro- dard procedures [2-4]. logical seasons of the year and that the total contents of the soluble forms of heavy metals (Hg, Ag, Pb) are lower than those in the basin RESULTS AND DISCUSSION of the Katun and Chuya rivers. The left trib- utaries Aley and Barnaulka produce minor ef- Water fects on the chemical flow of metals, inflow- The upper reaches of the Katun and Chuya ing with copper and zinc (Aley) and iron (Bar- rivers were explored in detail by the institutes naulka), the effects being especially pronounced of the Siberian Branch, Russian Academy of during spring flood [9]. Sciences (19891994), in efforts to investigate the distribution of mercury from the Aktash Distribution of heavy metals in water and Chagan-Uzun deposits and ore manifesta- along the river tions [5]. The total content of mercury in wa- ter was approximately 1.0 µg/l near the Aktash The results of HM determination in the deposit and 0.010.21 µg/l in the estuary of natural waters of the middle and lower Ob the Chuya. This figure decreased away from (8ig. 2, af) show that the dissolved 8e, Mn the deposits to 0.080.17 µg/l (section line near (see 8ig. 2, e, f) and other HM forms in the the Inya village) and to background values surface waters approximate the upper bound (0.0050.09 µg/l) at the closing section lines (Elik- of background contents [10, 11] for unpollut- monar village, Anos). According to the main ed waters. The spatial distribution of the sol- ion contents, the water of the Katun river ute 8e forms in the surface waters of the mid- basin probably belongs to the hydrocarbonate- dle and lower Ob reflect the influence of the calcium-magnesium type [6, 7]. According to tributaries. Thus pronounced concentrations 556 S. V. TEMEREV and V. M. SAVKIN 8ig. 2. Distribution of heavy metals along the river. were revealed on section line 8 (below the junc- ganese on section line 11 in the Ob is approxi- tion with the Chulym) and on section lines 7 mately doubled (see 8ig.