Geochemical Study of the Tundra Landscapes in the Yenisey Delta and Gulf Area

Geochemical study of the tundra landscapes in the Yenisey delta and gulf area

E.M. Korobova V.I. Vernadsky Insitute of Geochemistry and Analytical Chemistry, Moscow, Russia N.G. Ukraintseva & V.V. Surkov Moscow State University, Moscow, Russia J.B. Brown Norwegian Radiation Protection Authority, Osteras, Norway

ABSTRACT: Geochemical studies were conducted at four study sites in the Yenisey Estuary characterised by landscape cross-sections of the flood plain and adjacent watershed. Natural waters and soils formed on the originally frozen marine sediments, outcropping on landslide slopes, showed pronounced salinity and alkalinity. The variation in total salinity and ion composition of the sampled waters and the water-exchangeable soil sorption complex supported earlier data on freeze-thaw transformation of soils and ground waters. Stream flows, transporting waters enriched in iron and manganese from the flood plain swamps to the Yenisey River, could also be induced by freezing processes. Trace element distributions in soils may indicate atmospheric contamination of the southern tundra site by distant human sources, e.g. the 200 km distant Norilsk Cu-Ni Complex. A comparison of concentrations and distributions of chemical elements in soil and vegetation at different distances from the Kara Sea was made.

1 INTRODUCTION

Tundra landscapes are noted for their high sensitivity to anthropogenic impact owing to several factors including the presence of severe natural conditions, freeze weathering and a low rate of plant growth and regener- ation. The Lower Yenisey collects the global, regional (due to river transport) and local contamination from a vast drainage area. Concentrations of lead, copper and zinc in snow cover in the lower reaches of the Yenisey River are 3–5 times higher than those observed in the Yamal Peninsula and 10–15 times higher than those in the Canadian Arctic (Solomatin et al. 1989). The main objective of the present study was to inves- tigate the active layer of the Yenisey coastal plain and to Figure 1. Location of the study sites. estimate possible contamination of the terrestrial environment in the Yenisey estuarine zone. This paper river-eroded and reworked deposits. The area was describes field observations and provides results from covered by a thick (300–450 m) low-temperature preliminary hydrochemical and trace element analyses. permafrost ( 7°C) discontinued under the river channel (Ershov 1989). The mean annual temperature is 11.5°C, the monthly temperature amplitude 2 STUDY AREA AND METHODS reaches 38°C (at Vorontsovo). The prevailing wind direction changed from S, SE in January to NE in July The study took place in the middle of August 2001 in which suggests that contamination of the area from the period of close to maximum thaw depth. The four the local continental sources would potentially occur elaborated sites characterized the flood plain and the mainly in the winter. A thin active layer and a short Taimyr coastal zone and were representative of typical period of water exchange and cryogene concentration (middle subzone) and southern tundra areas. The sites of soil solution (Anisimova 1981) could contribute to were located within the delta, inlet and gulf sections contaminant conservation in local biogeochemical of the Yenisey estuary (Fig. 1). cycles. The influence of marine sources on element Watershed areas were formed from Pleistocene composition and water chemistry was expected to be marine sediments 2–5 to 100–170 m thick covering more pronounced on Cape Shaitansky. Each site was Palaeozoic trapp formation while flood plain areas characterized by landscape cross-sections of the flood were characterised by accumulation of weathered, plain area and the adjacent watershed areas of the

601 Taimyr Peninsula. Field studies included leveling, 400–500 g/m2 in short willow thickets, and reached description of the soil and vegetation cover, and sam- maximum values in tall shrub thickets that consider- pling of the watershed and flood plain plots. The struc- ably exceeded the phytomass levels of the watershed ture and texture of soil depth profiles were described areas. In typical tundra sub-zones, sites the overground in detail and sampled at study plots selected to pro- phytomass ranged from 36 to 820 g/m2. Maximum val- vide a range in conditions of river deposition and ues corresponded to the areas overgrown by shrubs atmospheric contamination. Soil profiles were sam- represented mainly by willow that supported the ear- pled continuously with regard to the generic soil hori- lier data (Ukraintseva et al. 2000). zons. Vegetation was sampled at 1–3m2 plots located The mean thaw depth on the watershed equaled over the soil profiles. Surface and ground water 51.6 9.2 cm under moss cover and 76.7 13.5 samples were collected at selected points of the cross- under lichen and grass cover confirming the presence section to characterize water migration parameters. of lower soil temperatures under thick moss cover The chemical composition of water samples was (Table 1). The gravimetric moisture content in peaty determined with the help of potentiometry (NO3 , Cl, layers was highly variable (74–280%, 63.4 40.4%, 3 PO4 ), ion-selective electrodes (NO3 , Cl ), titri- n 30) and in general higher than the levels associa- 2 metry (HCO3 ), nephelometry (SO4 ), photometry ted with loamy (40.8 22.5%, n 59) and sandy ones 3 (NH4 , PO4 ) techniques and AES-ICP (cations). (17.4 9.9%, n 21). Volumetric values ranged Accuracy of determination was 2–10%. The main from 19–58% based on average moisture contents for ions in filtered soil water extraction were determined each plot (Table 1) also reaching maximum values in by standard chemical methods of soil analysis peaty layers of flood plain depressions. (Arinushkina 1961). Air dried and homogenized soil and plant samples were analysed with the help of XRF 3.3 Water and soil water extraction salinity and spectrometers ORTEC-TEFA and SPARK-1. composition

3 RESULTS AND DISCUSSION 3.3.1 Water samples Salinity of the collected water samples varied from 3.1 General features of the studied sites 0.049 to 1.75 g/l and was in general higher at the flood plain plots compared to the watershed plots. The max- The landscape topographical sequence studied at imum value was found in water, collected on outcropping marine sediments (SK1-7) characterized by the Cape Shaitansky area included a narrow coastal zone 2 enhanced concentrations of Na Mg , HCO3 and with a sheared earth fragment sized 5 8 m, a land- 2 slide fissured slope shearing surface 20 m wide, and SO4 . High colority values presumably indicated a gently convex hill top sloping north-eastward to both a higher soluble organic and mineral colloidal content (Table 2). a swamp in an ancient river channel. A landscape cross- section near set. Vorontsovo was characterised by HCO3 dominated among anions (47–97 eq%) in all samples. However the samples from the gulf and inlet a 570 m wide and 3 m high (on average) right-side flood- – plain area, an adjacent slope and a watershed tundra sites (SK, VR) were noted for somewhat enhanced Cl portion (15–30 eq%) compared to the delta zone section. On Tysyara Island, the transect consisted of the two fragments 350 m and 80 m long situated on the (1.5–14 eq%). Na prevailed in waters formed on medium-level and high-level flood plain area respec- the landslide-exposed marine clay (85 eq%) and in the tively. A landscape transect near set. Karaul crossed northernmost thinly-thawed soil and water of the inner flood plain depressions (SK1-25, VR1-11a, 36–40 eq%) a low- and medium-level flood plain 600 m wide, a nar- 2 row gently sloping terrace on a debris cone, a slope and while Ca portion was the highest in the river and ox- the present watershed area (based on an ancient marine bow lake water (63 and 54 eq%). In most of the ground water samples Ca2 quota were almost equal to those of terrace) sloping to a lake depression. Actual thaw depth 2 ranged on the average from 30–50 cm on tops to Mg (35–49 eq%) and in Na – enriched waters mag- 80–90 cm on slopes and lowered on the flood plain. nesium-ion contents exceeded those of calcium. 3.3.2 Soil water extractions 3.2 Vegetation biomass and its role in the soil Water extractions were made for different depths and water retention and thaw depth generic horizons. Salinity levels, an order of magni- tude higher, and enhanced pH values were found in The density of growing vegetation on study plots in the water extractions from the soil developed on the young southern tundra sub-zone of the Yenisey Delta, ranged landslide shearing surface (SK1-10, 0.10–0.21%, from 20 to 190 g/m2 (100 g/m2 on average) for the pH 7.88–8.48) relative to the other sites and plots grassy communities, attained levels of approximately including the nearby watershed (Table 1). The total

602 Table 1. General field and preliminary laboratory information on the studied sites and plots.

Sampling Volumetric plots Sampling Soil, parent Max thaw water 1Mean 1 indices location Landscapes Habs, m material depth, cm cont., % pHw salinity, % Typical tundra subzone, Yenisey Gulf, Cape Shaitansky SK-1-15 72°04608 N Hill tops and slopes, 26.6 Peaty gley on clay 43* 12.2** 33.6 18.4 6.65 0.2 0.01 0.001 82°21595 E herbslichen/moss tundra eluvium n 11*** n 7n 4n 4 SK-1-10 72°04573 N Slope, young landslide, 7.2 Outcropping marine clay 86 18.2 18.6 16.3 7.9 0.55 0.17 0.044 82°21490 E grasses communities with buried peat horizon n 12 n 7n 5n 5 SK-1-25 72°04824 N Flood plain, moss/sedge 4.7 Peat gley on sandy and 29.0 54.6 16.6 4.49 0.1 0.033 0.02 82°21650 E marsh loamy alluvium with n 3n 5n 4n 5 buried peat layers Typical tundra subzone, Yenisey Inlet, set. Vorontsovo VR-1-16 71°43076 N Hill tops and slopes, under 37.1 Peaty humic soil on 21.5 12.5 7.3 0.14 0.033 0.004 83°31301 E shrub/lichen/moss tundra loamy eluvium n 9n 5n 5 VR-1-8 71°42981 N Flood plain, shrubby moss 4.2 Peaty gley on sandy 49.2 11.5 31.5 22.4 6.6 0.35 0.03 0.024 83°30504 E communities silty loam soil n 5n 4n 4n 4 VR-1-6 71°42889 N Flood plain, grasses 1.9 Peaty silt on sandy 107 24.3 55.5 21.1 83°10615 E communities alluvium n 5 or no n 5 permafrost down to 200 cm Southern tundra subzone, Yenisey Delta, Tysyara Island, Set. Karaul KR-2-5 70°04521 N Hill top, undershrub/ 45 Humic peat on clay 51.6 9.2 33.5 12.4 5.52 0.23 0.02 0.014 83°10615 E lichen/moss tundra loam eluvium n 5n 9n 5n 14 KR-2-0 70°04551 N Slope foot, herbaceous 29.2 Peaty humic soil on 76 12.3 29.5 6.3 83°10855 E willow shrubs sandy silty deluvium n 6n 5 KR-1-15 70°04408 N Flood plain, grass and 3.7 Peaty gley on loamy 80 32.3 8.1 5.25 0.38 0.02 0.006 83°10105 E sedge cover clay alluvium n 11 n 11 n 11 TS-1-8 83°22600- Flood plain, shrubby 4.8 Peaty gley with buried no permafrost 58.3 11.6 83°23336 E grass communities peat layers on loamy down to 140 n 8 70°31850- and sandy alluvium 200 cm TS-1-4 70°32359 N Flood plain, herbs/moss 4.9 Peaty silty gley soil 62.6 11.45 41.5 20.6 7.1 0.23 0.26 0.05 communities on loamy alluvium n 5n 11 n 6n 6

1Using water extraction * – mean, ** –standard deviation, ***n number of the measurements.

Table 2. Ion composition of the surface (l – lake, r – river) and the soil (s) water (meq/l).

2 2 2 Point Type Ca Mg Na K NH4 HCO3 SO4 Cl SK1-7 l 0.80 2.24 20.2 0.34 0.04 11.2 5.8 6.60 SK1-25 s 0.19 0.24 0.26 n/d 0.03 0.4 0.1 0.20 VR-0 r 1.13 0.35 0.27 0.04 0.02 1.1 0.1 0.30 VR1-6 s 0.38 0.16 0.29 0.23 0.03 0.7 0.1 0.25 VR1-11a l 0.33 0.43 0.56 0.01 0.04 0.6 0.3 0.45 VR1-14 s* 0.41 0.35 0.16 0.01 0.03 1.0 0.1 0.20 TS1-8 s* 3.15 3.04 0.37 0.08 0.10 6.5 0.1 0.20 KR1-15 l 1.03 0.69 0.15 n/d 0.02 1.6 0.1 0.10 KR2-0 l 0.23 0.19 0.06 0.01 0.01 0.5 0.1 0.10 KR2-0 s 0.22 0.19 0.06 0.01 0.01 0.5 0.1 0.05

* Water colority – 65–100° of the Pt-Co scale. ion content in water extractions of the flood plain and distinct enrichment of the Shaitansky plots SK1-10 accumulative soils was higher than that of the water- and SK1-25 in chlorine and sulfate ions compared to shed in most, but not all, cases. In vertical profiles the the southern sites (Fig. 2). extraction salinity increased in the lowest horizons and Profile SK-10 was completely sodium throughout. in topsoil where it often reached the maximum value. The Na portion amounted to 76–86 eq% and the The pH of water extractions were lower at the chloride-sulfate-sodium composition of water. Karaul watershed than at the other sites and dropped Extraction of the top soil horizon changed to hydro- in peaty lower-level landscapes i.e. accumulative soil, carbonate-sodium in deeper layers (Figs 2, 3). In on Cape Shaitansky down to 4.35–4.58 (SK1-25, lower layers, magnesium ions dominated over calcium Table 1). Anion deficiency in the ion balance believed (11 and 4 eq%). In the watershed profile SK-15 sul- usually to be filled by water-soluble organic sub- fate, magnesium and sodium ions prevailed through- 2 stances reached a maximum of 43% in the top organic out the whole profile. HCO3 (44–65 eq%) and Ca horizons on the watershed (VR1-16) and 60% in or Mg2 (25–56 and 15–44 eq%) were the dominant accumulative acidic soil samples (SK1-25). The com- soil water-soluble ions (following water extraction) position of water extractions and ion balance showed except for the lower horizons (23–41 cm deep) of the

603 Vorontsovo and magnesium-calcium in the distant delta zone. Soil water extractions showed the dominating presence of sodium cations on landslide plains and calcium in the delta area with a complex variation of cations in different soil horizons. An observed increase in water- exchangeable ion concentration at the bottom of the active layer was in accordance with earlier results that have shown elevated solution concentration on the Figure 2. Anion balance in the watershed top and lowest boundary with the permafrost table (Anisimova 1981). soil layers (SK1-10 – site and core Ids; depth, cm in brack- A decrease of water-soluble calcium in favor of sol- ets). Sites were positioned in N–S direction. uble sodium and partly magnesium in the lower soil horizons and hydrocarbonate-sodium composition of water in permafrost regions was described by other researches (Ivanov & Vlasov 1974, Anisimova 1981) and was explained by the incomplete secondary solution of the CaCO3 crystallized earlier either during (i) the freezing process or (ii) hydro-carbonate weathering of silicates due to CO2 losses. This process could explain the observed shift to hydrocarbonate-sodium or sulfate-magnesium composition in water extractions. Enhancement in soil water extraction salinity in the top organic soil layer can result from bio-accumulation, Figure 3. Cation balance in the watershed top and lowest concentration in salts in the upper layer during sum- soil layers (SK1-10 – site and core Ids; depth, cm in brackets). mer evaporation and the lower dilution of the lighter organic layers in the extraction. watershed profile VR1-16, which exhibited a charac- teristic HCO3 –Na water type. 3.4 Trace elements in soils Magnesium ions prevailed in the upper layer of the flood plain (VR1-8) and the intermediate beds of the Statistical parameters of trace element variation in the watershed (VR1-16, KR2-5) profiles. main generic soil horizons and sediment samples col- Soil water extraction from the delta island TS-4 lected at the study site are presented in Table 1. In profile had the same composition in the top layer, general, the levels did not exceed ecological limits while downward magnesium ion equivalent concen- accepted for the industrial regions of the Western trations exceeded that of calcium ions in the lower Europe (Fomin & Fomin 2000) but Cu, Pb and Cr loamy horizons and, unlike water samples, contained content were higher than the regulatory standard considerable levels of sulfate ions (30–47 eq%) espe- adopted for some plants (Sokolov & Chernikov 1999). cially in organic horizons. It is worth noting that certain heavy metals, already The Karaul watershed water extraction was present at naturally enriched levels because of the hydrocarbonate-calcium (Figs 2, 3) while water- nature of the parent rocks, can be enhanced still exchangeable complex in the flood plain peaty gley further because of inputs originating from human soil varied from sulfate-magnesium to hydrocarbonate- industrial activity (following distant transport and magnesium. precipitation). Therefore, the data need comparative analysis of element distributions in watershed and 3.3.3 General tendencies in water composition flood plain plots as well as in vertical soil profiles. Preliminary analyses of water samples and soil water Compared to the mean content of trace elements in extractions highlighted the considerable salinity and lithosphere and clays the soil samples were enriched alkalinity of landscapes formed on marine sediment out- in Cu, Pb, Cr and Co (Table 3). Average values were crops (arising from landslide processes). Further inland also higher than the corresponding range reported for from the estuary zone, surface and soil water anion com- the soils of Russia (Vinogradov 1957, Sokolov & position changed from chloride and sulfate-hydro- Chernikov 1999). Cu, Cr and V are known to exhibit carbonate to sulfate and hydro-carbonate solutions. higher contents in igneous basaltic rocks (Wedepohl Variation in cation composition is more compli- 1971). This (except for Pb), together with characteris- cated. In water samples, it changed from sodium on tic ratios Ni Co and V Cr, distinctly reflects Cape Shaitansky to sodium-magnesium-calcium at peculiarities of the regional geochemical background

604 Table 3. Mean concentration of heavy metals in soil hori- 1,5 zons (mg/kg, dry mass). 1

Heavy metals in studied samples 0,5 g/m2*cm Element Clark of the clay* Mean (m) Min Max V, %** n 0 Cu Zn Ni Co Cr V Pb Cu 45 73 21 182 48 39 SK_1_15 VR_1_16 KR_2_5 Zn 95 57 12 116 48 41 Pb 20 72 13 400 108 22 V 130 128 98 156 11 41 Figure 5. Trace element inventory in watershed soils. Ni 68 34 13 95 46 40 AA_1_11 – plot indices. Co 19 24 10 58 36 41 Cr 90 103 16 185 34 41 possibly reflecting a contamination source. However, *After Wedepohl 1971, **V STD/mean*100. low Cea for Cr and V and the relatively high Cr content of samples from Cape Shaitansky may suggest 12 their regional origin. 10 8 The obtained data support the hypothesis that top- 6 soils had received additional inputs of Cu and Pb and Cea 4 possibly Zn in watershed landscapes. This corre- 2 0 sponds with the data on snow contamination in the lower Yenisey reaches (see introduction). The vertical distribution of the trace elements studied TS_1_4 VR_1_8 KR_2_5 KR_2_0 SK_1_10 SK_1_15 SK_1_25 VR_1_16 KR_1_15 Cu/Ti Ni/Ti Zn/Ti Pb/Ti in soils, conforms to the theory of geochemical barriers in soils. Ba, V, Cr, Zn, Fe and sometimes Cu (profile Figure 4. Heavy metal accumulation in the top soil layer SK1-15) concentrate above the permafrost table on related to the lowest horizon (Cea (Ats/Tits)/(Alh/Tilh), sorption-gley barrier. Consideration of the correlation where A – the element content, Ti – titanium content in top- between trace element concentrations in different soil soil (ts) and the lowest horizon (lh) correspondingly). horizons proved that a biogeochemical barrier is most typical for Cu and Zn (r0.05 0.627, n 11). In the formed through processes including the long-term gley loamy and clay horizons significant correlation weathering and erosion of the basaltic rocks of the was found for Ni and V with Fe (r0.05 0.861, 0.674, Siberian platform enriched in Co, Ni, Cu and other n 11) and Mn (r0.05 0.823, 0.785, n 11). Co elements (Nesterenko & Almukhamedov 1973). exhibits a rare increase in concentration at the sorption According to the variation coefficient value (Table 3), barrier and correlates in general with the total Fe con- the analyzed elements form the following descending tent mainly in non-organic horizons. order: Pb Cu, Zn, Ni, Fe, Mn Co, Cr V, T i . Redox-sensitive iron and manganese mobilized in The topsoils of most accumulative plots were swamps and concentrating in the unfrozen solution in enriched in trace elements as compared to the water- the active layer (Boike & Overduin 1999) could possi- shed sites. An exception to this trend was observed at bly be discharged with water under pressure during the Karaul site. Calculation of the top layer enrich- thawing or freezing forming Fe- and Mn-enriched ment factor normalized by titanium content to exclude streams. This process may have been responsible for dilution by the organic matter (Cea) showed pro- the elevated concentrations analysed in some Voront- nounced topsoil accumulation of Pb, Cu and Zn sovo samples. We witnessed Fe-enriched streamlets (Fig. 4). Accumulation was the highest at watershed flowing to the Yenisey sandy beach from the flood locations and maximum in the accumulative peaty plain swamp. The water sample from the small flood landscape characterized by plot SK1-25. plain lake contained considerable amounts of dis- Cea values for Co, V and Cr similar to Ni were solved iron (0.21 mg/l) and manganese (0.01 mg/l); below 1 except for Karaul site (Cea 1.0–1.4) and manganese concentrations in the ground water of the SK1-25 (Cea 2–4) suggesting natural origin and low flood plain reached 2.8 mg/l (point VR1-6). distribution. Pb in topsoil samples is believed to indicate regional and local contamination, while behavior of 3.5 Trace elements in plants Cu and Zn characterized both natural accumulation and possible contamination from the Norilsk mining Concentrations of trace elements in selected plant industry. Calculation of trace element inventories species and groups are below the restricted values in the 1 cm-thick top-soil layers per square meter, (Sokolov & Chernikov 1999). Zn is a known biophyl showed that the watershed near set. Karaul, closest to element and increases the frost-resisting capacity of Norilsk, contains considerably higher amounts of Cu, plants. The element is accumulated to a considerable Zn, Cr, V, and Pb than more distant watersheds (Fig. 5) degree in willow leaves (135–160 mg/kg, dry mass)

605 Coastal areas of the Taimyr Peninsular are characterized by landslide phenomena, exposing, in the Yenisey Gulf, the originally frozen marine sediments that lead to a pronounced salinity and alkalinity of the surface and soil water, and strongly influences the specific ion composition. The impact of the marine environment on the terrestrial communities in the estuarine zone was also reflected in Cl content in plants and the transfor- Figure 6. Zinc in dominating species of tundra landscapes mation of the water surface and soil water anion (mg/kg, DM). composition from hydro-carbonate to sulfate-hydrocarbonate and chloride. and mosses (51–110 mg/kg) compared to grasses and horsetail (40 mg/kg, Fig. 6). Mosses are also noted for higher levels Cu contain ACKNOWLEGEMENTS higher amount of Ni in Vorontsovo plots, and grasses are enriched in Cu (6–8 mg/kg) at Vorontsovo and the The work has been carried out in the framework of Karaul flood plain plots. Lichens exhibited minimum the INCO-Copernicus project “Establish” (Gerland & element concentrations. No uniform trends are evident Brown 2001). Authors are much obliged to Dr. in trace element concentrations in a seaward direction. O. Stepanets and the crew of the research vessel Willow leaves show considerable accumulation of “Akademic Boris Petrov” for assistance and to Dr. Cu, Pb and Zn on the Vorotsovo flood plain plots, sug- V. Linnik for valuable participation in the field studies. gesting a possible contamination input. Horsetail and all species grown on the fresh outcropping marine sediments demonstrated pronounced increases in Cl REFERENCES concentration up to 0.84–1.21%. Anisimova, N.P. 1981. Cryohydrogeochemical peculiarities of the frozen zone. Novosibirsk: SO NAUKA: 4 CONCLUSIONS Arinushkina, E.V. 1961. Manual for the soil chemical analysis. Moscow: Moscow State University. The active layer in the studied southern tundra and Boike, J. & Overduin P.P. 1999. Seasonal Changes in Hydrology, flood plain soils close to maximum thaw period was Energy Balance and Chemistry in the Active Layers of naturally thicker than in typical tundra watershed con- Arctic Tundra Soils in Taimur Peninsula, Russia. In H. Kassens et al. (eds), Land-Ocean Systems in the Siberian ditions. Overground phytomass varied significantly Arctic: Dynamics and History: 299–306. Berlin: Springer. depending upon the willow and alder species. Weakly Ershov, E.D. (ed.) 1989. USSR Geokryologia. Western Siberia. decomposed organic debris played a significant role Moscow: Nedra. Fomin, G.S. & Fomin, A.G. 2000. The soil. International stan- in water accumulation in soil horizons. dards of quality control and ecological safety. Reference Freeze-thaw processes supposedly contributed to the book. Moscow: Gosstandart. transformation of the ion composition of the ground Gerland, S. & Brown, J. (eds). 2001. Estuarian specific transport water and water-exchangeable soil sorption complex, and biogeochemically linked interactions of selected heavy metals and radionuclides. Annual report for project ICA-CT- as both exhibit a relative enrichment in sodium and 2000-10008 “ESTABLISH”. Osteras: NRPA. sometimes magnesium and sulfate ions. Increased Ivanov, A.V. & Vlasov, N.A. 1974. Influence of cryogene salinity and relative trace element accumulation obser- processes on formation of hydro-carbonate-sodium waters. ved at the bottom of the active layer could result from Hydrochemical materials 60: 55–61. Nesterenko, G.V. & Almukhamedov, A.I. 1973. Geochemistry of solution concentration over the permafrost table. differentiated traps. Moscow: Nauka. Increased Cu, Pb and partly Zn concentrations in Sokolov, O.A. & Chernikov, V.A. 1999. Ecological safety and sus- the top soil horizons on watershed closest to Noril’sk tainable development. Atlas of heavy metal distribution in the environmental components. Pushchino: Nauka. source, are believed to provide tentative evidence for Solomatin, V.I., Evseev, A.V., Korzun, A.V. & Kuznetsova, A.V. an atmospheric input to the inventory of these ele- 1989. Geochemistry of the atmospheric precipitation, the ments at the studied tundra areas. Element accumula- surface waters and underground ice in Arctic landscapes. tion at the inland depressions was likely to occur due Moscow: VINITI. Ukraintseva, N.G., Leibman, M.O. & Streletskaya, I.D. 2000. to natural processes. Peculiarities of landslide process in saline frozen deposits of Biophyl elements, such as Zn and partly Cu, Central Yamal, Russia. In Landslides in research, theory and concentrated in the top soil layers and above the practice. Proc. intern. symp., Cardiff, 26–30 June 2000: permafrost table, while “abiogenic” elements usually 1495–1500. London: Telford Publishers. Vinogradov, A.P. 1957. Geochemistry of the rare and trace exhibited close to uniform vertical distributions or elements in soils. Moscow: ANSSSR. increased with depth. Wedepohl, K.H. 1971. Geochemistry. New York: Helt.

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