Trace elements and precious metals in snow samples from the immediate vicinity of nickel processing plants, Kola Peninsula, northwest Russia

ENVIRONMENTAL POLLUTION

Environmental Pollution 102 (1998) 221±232

Trace elements and precious metals in snow samples from the immediate vicinity of nickel processing plants, Kola Peninsula, northwest Russia D. Gregurek a,*, C. Reimann b, E.F. Stump¯ a a

Institute of Geological Sciences, University of Leoben, Peter-Tunner St. 5, A-8700 Leoben, Austria b Geological Survey of Norway, PO Box 3006, Lade, N-7002 Trondheim, Norway Received 3 December 1997; accepted 16 April 1998

Abstract The chemical composition of snowpack samples taken in the immediate vicinity (1±8 km) of nickel mines and processing plants on the Kola Peninsula, northwest Russia, was investigated. Snowpack sampling was carried out in March 1996 in the surroundings of the ore roasting and dressing plant at Zapoljarnij, and the nickel smelters at Nikel and Monchegorsk. The collected snow cover represents the total atmospheric input of heavy and noble metals during the 1995/96 winter season. The snow samples were analysed for up to 44 elements, using ICP-MS, ICP-AES, ion chromatography and graphite furnace atomic absorption techniques. Results indicate that all trace elements and precious metals show unusually high concentrations in the vicinity of the nickel ore roasting plant and smelters. Analytical data also reveal typical ®ngerprints of the two ore components (Noril0 sk and Pechenga ore) used in the processes. # 1998 Elsevier Science Ltd. All rights reserved. Keywords: Trace elements; Precious metals; Snow; Industrial emissions; Kola Peninsula

1. Introduction The Geological Surveys of Finland, Norway, in cooperation with the Central Kola Expedition in Russia, have in 1992 started an environmental geochemical mapping project (see http://www.ngu.no/Kola) of the western half of the Kola Peninsula and the adjacent areas in Norway and Finland (Fig. 1). The eastern and western project area borders are 24 E and 35 300 E, respectively. The Arctic Circle is the southern, the Barents Sea the northern project border. The Kola ecogeochemistry project consists of three phases: a pilot project, which took place in 1992±93 to harmonise ®eld methods and to test suitable sample media focusing on environmental pollution around Nikel (Reimann et al., 1996), followed by a catchment study in 1994±95 (AÈyraÈs and Reimann, 1995; Reimann et al., 1997a, b) and a regional geochemical mapping phase in 1995±96 (AÈyraÈs et al., 1997; Reimann et al., 1998). During the catchment study the following media were sampled:

* Corresponding author. Fax: +43-3842-47016; e-mail: gregurek@ unileoben.ac.at 0269-7491/98/$19.00 # 1998 Elsevier Science Ltd. All rights reserved. PII: S0269 -7 491(98)00090 -6

snow, rain water, stream water, organic stream sediments, terrestrial moss, topsoil (0±5 cm), complete podzol pro®les, quaternary deposits and bedrock. The complete geochemical map coverage of the entire area (188 000 km2) presenting the regional distribution patterns of more than 50 elements in ®ve di€erent sample media is available since March 1998 (Reimann et al., 1998). The sample media are terrestrial moss, humus, topsoil (0±5 cm) and complete podzol pro®les (®ve layers sampled). The Kola Peninsula ranges second only to Noril0 sk, Siberia, as an area heavily polluted by nickel mining, roasting and smelting activities. Over the past 60 years the Russian non-ferrous metal processing industry has led to the development of hundreds of square kilometres of industrial deserts around the plants, where all vegetation and humus are virtually destroyed. High element levels due to pollution from the nickel industry have, in the course of the project, been recognized in many different sample media: snow cover, rainwater, terrestrial moss, topsoils, the O-horizon of soils and stream water (AÈyraÈs et al., 1995; Caritat et al., 1996a, b; Niskavaara et al., 1996; Reimann et al., 1996, 1997a, b, c). The serious damage to the ecosystem can easily be detected

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Separate chemical analyses of two snow fractions (®ltered meltwater and ®lter residues) facilitate recognition of the mode of element deposition on snow. This can be used as a powerful tool for ®ngerprinting the emission sources. 2. Sampling and analytical procedure 2.1. Sampling

Fig. 1. Location map of the area studied, showing the position of the major industrial plants.

and outlined on satellite images (Hùgda et al., 1995; Tùmmervik et al., 1995). The ore roasting and dressing plant at Zapoljarnij, the nickel smelter at Nikel, both located in the western part of the Kola Peninsula, and the nickel (Ni), copper (Cu) and cobalt (Co) smelter complex at Monchegorsk, located in the central part of the Kola Peninsula, are the major point sources of emissions (Fig. 1). The almost 3km long open-pit Cu±Ni ore mine (Zapoljarnij ore deposit) is a further possible source of dust input to the snow. The annual emissions from all three Ni processing plants together are 300 000 t of SO2, 1900 t of Ni and 1100 t of Cu (Reimann et al., 1997a), thus representing some of the world's largest point-source emitters (Gunn et al., 1995). Intensive studies of the snowpack geochemistry of the Kola Peninsula have been carried out in Russia, but with the exception of some recent papers (Makarova et al., 1994; AÈyraÈs et al., 1995; Ja€e et al., 1995; Kelley et al., 1995; Reimann et al., 1996; Caritat et al., 1998) the Russian data were not published internationally. In contrast to Caritat et al. (1998) who studied the snow chemistry in eight catchments widely spread over the whole Kola Peninsula (two were at a distance of about 10 km from Monchegorsk and Zapoljarnij, respectively), our investigations were carried out on snow samples collected in the immediate vicinity (1±8 km) of the industrial plants. They thus represent the total atmospheric deposition of trace elements and precious metals during the 1995/96 winter at a very close distance to the pollution sources.

Snowpack sampling was carried out in March 1996. A total of 15 snowpack samples were taken; 7 near the Monchegorsk smelter complex, 4 near the Nikel smelter and 4 near the ore roasting and dressing plant at Zapoljarnij. Sample sites were chosen based on accessibility in deep winter, major wind directions (from south to north towards the Barents Sea), distance to pollution sources (generally between 1.5 and 8 km) and greatest possible distance to major roads. Snow depth was measured at 20 locations over a 5050-m square prior to selecting the exact sample spot as close as possible to the centre of the square. The total depth of snow cover was between 70 and 110 cm. Sampling at places where there were ice layers recorded in the snow (indication of melting processes during winter that could mean fractionation of elements in the snow pro®le) was avoided. At each locality two samples were taken: (1) about 4±6 kg snow for trace metals analysis (up to 39 elements) and (2) about 20±28 kg snow for analysis of precious metals (Rh, Pd, Pt, Au and Te) and for mineralogical investigations. A specially developed colourless Plexiglass tube of 1-m length and 92.5-mm internal diameter was used for sampling (Soveri, 1995). Replicate samples could not be taken due to logistical problemsÐvery big snow samples of >20 kg per site that had to be kept frozen at all times prior to delivery to the Finnish laboratory in winter. Snow sample duplicates had been taken in earlier stages of the project (pilot projectÐ Reimann et al., 1996; catchment studyÐCaritat et al., 1998), which were also used to develop the technique to perfection. Snow samples were stored in polyethylene bags and kept frozen. The bags were sealed in the ®eld, kept frozen at all times and delivered to Finland. In the laboratory they were transferred to a clean room environment. Subsequently ®ve samples were melted per day and analysed the following day. Melting took place in a fume hood, one edge of the polyethylene bags was cut o€, the samples were placed on top of an on line ®ltration unit and left to slowly melt at room temperature, which took approximately 1 day for ®ve samples. This procedure proved to be best suited to avoid the loss of any particulate material due to adsorption to the walls of the bags which can be a major problem if the samples melt in the bags prior to preparation.

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Mg, Na, P, S, Sc, Si, Y) and ICP-MS (for Ag, Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, Th, Tl, U, V, Zn). The results were recalculated to the volume of snow meltwater to allow direct comparison with the meltwater results. Detection limits are given in Table 2. For the chemical analysis of platinum group elements (PGEsÐRh, Pt, Pd), Au and Te, 6 kg of snow was ®ltered through a membrane ®lter (0.45 mm). The entire ®lter with the residues was ashed at 500 C and the ash was digested with aqua regia. Au, Pd, Pt and Rh were preconcentrated using mercury as a collector. The elements were determined by graphite furnace atomic absorption techniques (GFAAS; Kontas et al., 1990; Niskavaara and Kontas, 1991) and the results were recalculated to original snow weight. Detection limits are given in Table 5.

2.2. Analysis For chemical analysis of trace elements, about 2-kg subsamples were ®ltered through 0.45 mm Millipore1 mixed cellulose ®lters using a vacuum pump. The ®ltered melt water was divided in two aliquots. The ®rst aliquot was acidi®ed with suprapure nitric acid (Romil1) and analyzed with ICP-AES (for Ca, Cu, Mg, Na, P, S, Si) and ICP-MS (for Ag, Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Fe, K, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, Th, Tl, U, V, Zn). The second non-acidi®ed aliquot was analyzed by potentiometry (for F) and by ion chromatography (for Brÿ, Clÿ). Detection limits are given in Table 1. The ®lter residues (concentrate, collected from 2-kg subsample) were digested with 10 ml concentrated nitric acid in a microwave oven, diluted to 50 ml with distilled water and analyzed with ICP-AES (for Ca, Fe, K, La,

Table 1 Analytical results of snow, meltwater fraction. Values in mg/litre Element

DL

M-1

M-2

M-3

M-4

M-5

M-6

M-7

Z-8

Z-9

Z-10

Ag (1) Al (1) As (1) B(1) Ba (1) Be (1) Bi (1) Ca (2) Cd (1) Co (1) Cr (1) Cu (2) Fe (1) K (1) Li (1) Mg (2) Mn (1) Mo (1) Na (2) Ni (1) P (2) Pb (1) Rb (1) S (2) Sb (1) Se (1) Si (2) Sr (1) Th (1) Tl (1) U (1) V (1) Zn (1) Br (3) Cl (3) F (3)

0.01 0.08 0.14 0.08 0.05 0.11 0.19 0.04 <0.01 <0.01 <0.01 0.1 143 133 68.7 54.5 65.3 130 53.6 35.5 16 68.2 0.05 6.2 5.63 4.7 4.76 3.66 7.58 12.1 0.51 0.2 0.13 0.5 1.69 0.63 0.6 0.5 1.05 1.41 5.27 3.39 3.21 2.46 0.04 3.35 5.08 3.08 2.11 2.12 3.65 3.44 1.02 6.6 0.64 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.03 0.17 0.59 <0.03 0.06 0.04 0.04 0.19 <0.03 <0.03 <0.03 10 300 600 200 200 300 500 2200 2800 2600 1400 0.02 9.01 14.9 18.7 4.4 5.38 26.1 56.2 1.16 0.27 0.43 0.02 29.7 27.8 11.8 9.96 17.2 141 360 55.1 6.36 14.6 0.2 0.98 1.16 0.91 0.49 0.82 2.55 <0.2 <0.2 <0.2 0.22 0.04 460 680 1040 340 640 2700 4820 1040 110 530 10 110 120 50 50 60 220 30 1.0 20 70 10 300 200 190 60 110 150 340 180 210 150 0.3 0.4 0.5 0.7 <0.3 <0.3 0.83 1.95 0.82 0.33 0.34 10 450 160 120 110 180 310 860 2870 760 1340 0.02 8.15 9.65 5.25 2.87 3.45 11.1 37.3 46.3 23.3 19.6 0.03 0.65 0.73 0.38 0.38 0.39 0.57 2.11 0.07 0.04 <0.03 100 3900 700 700 600 1000 1200 4500 4500 3400 4400 0.06 484 530 247 118 210 1110 3830 1790 182 441 100 <100 <100 <100 <100 <100 <100 <100 <100 <100 <100 0.03 9.72 6.37 15.2 4.98 6.68 19.9 0.96 0.06 0.1 0.14 0.01 0.29 0.33 0.28 0.12 0.18 0.38 0.83 0.44 0.35 0.22 50 1470 1850 1140 740 1200 2790 9140 7390 3220 3250 0.02 0.12 0.14 0.07 0.05 0.1 0.14 0.45 <0.02 0.05 <0.02 0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 100 <100 <100 <100 <100 <100 <100 <100 <100 <100 <100 0.1 4.38 3.57 2.99 2.5 4.23 5.35 16.5 10.5 14.1 6.08 0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 0.02 0.07 0.04 0.05 0.02 0.04 0.13 0.28 0.06 0.04 0.04 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.02 12.7 10.4 7.9 5.85 13.2 14.7 1.26 <0.02 0.04 <0.02 0.1 30.2 34.2 42.9 16.1 21.5 82.5 199 23.5 24.1 12.8 30 70 <30 50 70 <30 70 60 70 30 60 100 7550 1440 1560 1200 1760 3140 7280 7860 6160 7480 30 <30 60 <30 90 <30 70 210 130 60 80

Z-11

N-12

N-13

N-14

N-15

<0.01 29.5 0.38 3.54 0.94 <0.1 <0.03 600 0.15 2.11 0.29 70 130 280 <0.3 970 7.27 <0.03 7100 64.9 <100 0.39 0.16 1270 <0.02 <0.05 <100 6.14 <0.02 0.03 <0.01 0.14 28 140 12700 <30

<0.01 5.64 0.43 1.24 0.26 <0.1 <0.03 200 0.06 0.27 <0.2 10 20 120 <0.3 360 2 <0.03 2700 10.9 <100 0.47 0.06 490 <0.02 <0.05 <100 2.25 <0.02 0.03 <0.01 0.24 3.81 80 5070 <30

<0.01 5.54 0.37 1.67 0.18 <0.1 <0.03 200 0.05 0.19 <0.2 10 20 150 <0.3 460 2.08 <0.03 3700 7.14 <100 0.41 0.08 510 <0.02 <0.05 <100 2.81 <0.02 0.03 <0.01 0.23 3.44 100 6460 130

<0.01 24.7 0.65 0.9 0.7 <0.1 <0.03 300 0.31 2.26 <0.2 110 50 110 <0.3 310 4.31 <0.03 1900 91.7 <100 0.21 0.11 780 <0.02 <0.05 <100 2.89 <0.02 0.04 <0.01 0.79 7.26 60 3790 60

<0.01 217 3.81 1.68 2.11 <0.1 <0.03 1300 2.64 18.1 0.47 1320 240 140 0.47 1020 18.9 0.05 2800 914 <100 0.8 0.4 3700 0.1 <0.05 <100 7.51 <0.02 0.15 <0.01 1.44 31.3 90 4900 220

Abbreviations: M, Monchegorsk; Z, Zapoljarnij; N, Nikel; DL, detection limit. (1) analysis with ICP-MS; (2) analysis with ICP-AES; (3) ion chromatography; <`number', values below detection limit.

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Table 2 Analytical results of snow, ®lter residue fraction. Values in mg/litre Element

DL

M-1

Ag (1) Al (1) As (1) B (1) Ba (1) Be (1) Bi (1) Ca (2) Cd (1) Co (1) Cr (1) Cu (1) Fe (2) K (2) La (2) Li (1) Mg (2) Mn (1) Mo (1) Na (2) Ni (1) P (2) Pb (1) Rb (1) S (2) Sb (1) Sc (2) Se (1) Si (2) Sr (1) Th (1) Tl (1) U (1) V (1) Y (2) Zn (1)

0.02 1.46 1 816 0.3 24.7 1 <1.0 0.08 3.81 0.2 <0.2 0.06 4.58 10 74 0.04 0.54 0.05 21.8 0.05 5.86 0.05 187 10 1070 20 39 0.07 <0.07 1 <0.6 10 111 0.05 6.13 0.06 1.98 10 27 0.1 402 0.5 2.1 0.2 10.7 0.02 0.31 5 351 0.04 0.43 0.01 0.07 1 2.01 5 54 0.2 1.59 0.04 0.05 0.04 <0.04 0.02 <0.02 0.05 11.3 0.01 0.07 0.02 6.18

M-2

M-3

M-4

M-5

1.25 1020 16.9 <1.0 4.64 <0.2 4.54 123 0.73 17.1 6.73 272 1290 132 <0.07 0.65 312 8.68 2.01 23 366 3.1 10.1 1.09 419 0.25 0.11 1.71 61 2.49 0.14 <0.04 0.02 15.1 0.13 6.31

0.88 193 14.0 <1.0 2.51 <0.2 1.9 39 0.53 8.84 2.8 159 504 53 0.07 <0.6 50 3.87 1.05 61 188 1.6 10.4 0.25 247 0.24 0.02 1.68 51 3.71 0.06 <0.04 <0.02 7.77 0.12 4.36

0.41 158 6.33 <1.0 1.52 <0.2 1.9 30 0.22 5.64 2.31 86 350 3.1 <0.07 <0.6 53 1.95 0.62 27 112 1.1 3.58 0.15 191 0.15 0.02 <1.0 39 1.18 <0.04 <0.04 <0.02 3.7 0.04 1.83

0.61 103 9.91 <1.0 1.56 <0.2 2.99 32 0.24 8.66 2.19 102 349 <20 <0.07 <0.6 34 1.62 1.08 12 138 1.6 3.5 0.11 202 0.21 0.02 1.62 25 1.53 <0.04 <0.04 <0.02 5.83 0.04 2.35

M-6

M-7

Z-8

Z-9

Z-10

4.56 3.15 <0.02 0.77 1.64 565 3740 6910 3760 2720 105 345 174 24.1 52.5 1.0 4.58 45.9 9.36 15.6 5.47 21.2 <0.08 17.2 5.98 <0.2 <0.2 <0.2 <0.2 <0.2 17.30 38.4 <0.06 0.17 0.32 77 667 3020 1320 619 1.8 7.4 2.88 0.48 0.85 105 346 1160 151 338 15.8 96.6 281 83 137 937 8020 20200 2300 5010 2720 16500 28400 23400 38200 52 286 654 223 112 <0.07 1.4 6.2 1.5 0.9 0.6 3.22 5.5 3.74 2.16 231 2210 65000 6320 11200 9.93 72.5 344 114 117 9.66 33.7 3.36 0.79 1.18 26 135 17 200 69 1320 5470 38500 4400 10700 30 97 274 135 78 39.5 125 0.11 10.9 8.36 0.47 2.37 <0.02 1.85 0.89 1430 7650 40800 9230 20100 1.14 1.9 <0.04 0.08 <0.04 0.1 0.7 5.02 0.79 1.07 8.95 30.3 26.4 3.72 6.93 47 74 153 120 96 2.81 13.4 5.67 9.12 4.94 0.07 0.35 0.56 0.37 0.21 0.1 0.29 <0.04 0.06 0.08 0.04 0.2 0.25 0.13 0.09 53.2 98.2 43.1 22.9 25.6 0.08 0.55 3.05 0.85 0.62 15.8 60.4 210 54.2 62.8

Z-11

N-12

N-13

0.16 396 6.15 2.0 1.13 <0.2 <0.06 98 0.11 36.1 17.9 470 7010 <20 <0.07 <0.6 1980 24.9 0.31 43 1130 1.5 1.21 0.16 2440 <0.04 0.17 1.66 38 0.8 <0.04 <0.04 <0.02 3.38 0.11 8.04

<0.02 17.2 0.65 <1.0 0.17 <0.2 <0.06 1.0 <0.04 1.45 0.78 16.4 171 <20 <0.07 <0.6 46 0.53 <0.06 32 42.7 2 0.22 0.02 111 <0.04 0.01 <1.0 7 <0.2 <0.04 <0.04 <0.02 0.16 <0.01 0.88

<0.02 21.8 0.91 <1.0 0.26 <0.2 <0.06 14 <0.04 1.41 0.77 17.1 185 <20 <0.07 <0.6 38 0.97 <0.06 21 39.9 2 0.35 0.03 103 <0.04 0.01 <1.0 7 <0.2 <0.04 <0.04 <0.02 0.21 <0.01 2.6

N-14

N-15

0.12 1.47 1230 5680 1.1 148 1.95 8.65 3.7 27.1 <0.2 <0.2 0.08 1.02 444 1700 0.12 1.32 24.8 329 46.7 219 243 4840 9100 39300 89 461 <0.07 1.3 0.95 3.97 2620 8880 37.2 176 0.37 2.89 119 613 503 8320 1.9 68 2.85 38.1 0.46 3.15 1320 10300 <0.04 0.07 0.41 1.43 1.5 14.1 54 102 3.65 21.1 0.07 0.44 <0.04 0.23 0.05 0.23 11.7 82.4 0.25 0.95 10.8 83

Abbreviations as in Table 1.

2.3. Quality assurance and control The chemical laboratory of the Geological Survey of Finland is equipped with clean room technology and accredited according to the EN 45001 standard and the ISO Guide 25. The ICP-AES and ICP-MS multielement calibrations were performed with standards provided by SPEX Industries2, USA. For melt water analysis by ICP-MS, certi®ed reference materials SLRS2 (National Research Council, Canada) and NIST 1643c (National Institute of Standards and Technology, USA) were used. For Te, Au, Pd, Pt and Rh analysis by GFAAS, standards produced by Spectrascan were used. As blank samples, 5-litres of distilled water samples were ®ltered ®ve times and the aliquots were analysed in the same way as samples. The ®lter paper blanks were digested and analysed in the same way as the samples. These results were compared with un®ltered distilled water and ®lter paper results. All blanks were lower

than the detection limit, except for S and Zn in membrane ®lter paper; the results of ®lter residues were corrected for these values. Detection limits were set ®ve times the standard deviation of the blank samples. Interference corrections were made according to standard ICP procedures. Quality control procedures for water analysis includes frequent analysis of an in-house water standard, sample blanks and the duplicate analysis of every tenth sample. 3. Results and discussion 3.1. Trace metals The analytical results of multi-element analysis methods (ICP-MS, ICP-AES) are given in Table 1 for the meltwater fraction, and in Table 2 for ®lter residues, for all three localities (Nikel, Zapoljarnij and

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elements, especially Al, As, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, S, Sc, V, Y and Zn (Table 3). The highest enrichment of most elements (Al, B, Ca, Co, Cr, Cu, K, La, Li, Mg, Mn, Ni, P, S, Sc, Si, Y, Zn) is recorded in Zapoljarnij (Table 3). The samples at Nikel show the highest levels for Ba, Fe, Na, Sr. As, Cd, Mo, Pb, Sb and V show the highest enrichment factor at Monchegorsk. Compared to Nikel and Monchegorsk, high levels of elements for Zapoljarnij cannot only be attributed to smoke stack emission from the ore roasting plant, but also to dust from the surrounding open-pit (Zapoljarnij ore deposit). Elements such as Al, Co, Cr, Cu, Mg, Ni, S, Si and Zn are primary compounds of the local Pechenga ores which are mined nearby and processed in the ore roasting and dressing plant at Zapoljarnij.

Monchegorsk). Some of the analyzed elements in the meltwater fraction are below the detection limit (Be, P, Se, Si, Th, U for all three localities and Ag, Bi for Zapoljarnij and Nikel). In the ®lter residues only Be was below the detection limit for Monchegorsk, Zapoljarnij and Nikel. Results indicate that most elements show unusually high concentrations in the vicinity of the Ni processing plants at Nikel, Zapoljarnij and Monchegorsk in both fractions. The trace metal content in the snow ®lter residues for all three localities was normalized to background levels. Data from Finland were taken as a representative background because, with the exception of geogenic dust and far-travelled aerosols, there are no other in¯uences on the element levels in snow (Reimann et al., 1996). The northwestern part of Finland is one of the most pristine regions remaining in Europe and this choice of a background facilitates estimates of element enrichment in snow impact by the local Ni processing industry (Caritat et al., 1998). Enrichment factors, calculated as the element concentration in the snow ®lter residues versus background level (C7+C8 as conservative(high) estimate of background), for snow ®lter residues from Nikel, Zapoljarnij and Monchegorsk exhibit a signi®cant enrichment of all

3.2. Comparison with earlier published data Table 4 compares total snow concentrations (®lter residue plus melt water) for selected elements of our study (all three localities) with data published by Caritat et al. (1998). The calculated values represent an average of element concentrations in snow ®lter residue plus melt water fraction for each locality. Generally, as

Table 3 Enrichment factors (snow ®lter residues/background levels) for snow ®lter residue fraction. Highest values in bold ef

M-1

M-2

M-3

M-4

M-5

Al As B Ba Ca Cd Co Cr Cu Fe K La Li Mg Mn Mo Na Ni P Pb S Sb Sc Si Sr Th V Y Zn

71 89 17 14 9 82 56 47 21 33 ± ± ± ± ± 14 17 9 6 6 1 1 ± ± ± 11 15 11 4 5 436 342 177 113 173 17 19 8 7 6 748 1088 636 344 408 107 129 50 35 35 4 13 53 31 ± ± ± 1 ± ± ± 9 ± ± ± 11 31 5 5 3 24 33 15 8 6 28 29 15 9 15 3 2 6 3 1 4020 3660 1880 1120 1380 11 17 9 6 9 36 34 35 12 12 70 84 49 38 40 1 ± ± ± ± 7 11 2 2 2 5 6 5 4 3 24 38 57 18 24 ± ± ± ± ± 226 302 155 74 117 7 13 12 4 4 13 13 9 4 5

M-6

M-7

Z-8

Z-9

Z-10

Z-11

N-12

N-13

N-14

N-15

Backgrounda

49 350 3 20 1 36 2040 45 3748 272 5 ± 9 23 38 138 3 13200 16 132 286 2 10 5 43 ± 1064 8 33

325 1150 15 77 7 148 6920 276 32080 1650 29 20 46 221 279 481 14 54700 52 417 1530 4 70 7 206 1 1964 55 127

601 590 153 ± 30 58 23200 803 80800 2840 65 89 79 6500 1323 48 2 385000 148 0 8160 ± 502 15 87 1 862 305 442

327 80 31 63 13 10 3020 237 9200 2340 22 21 53 632 438 11 20 44000 73 36 1846 ± 79 12 140 ± 458 85 114

237 175 52 22 6 17 6760 391 20040 3820 11 1 31 1120 450 17 7 107000 42 28 4020 ± 107 10 76 ± 512 62 132

34 21 7 4 1 2 722 51 1880 701 ± ± ± 198 96 4 4 11300 8 4 488 ± 17 4 12 ± 68 11 17

2 2 ± 1 ± ± 29 2 66 17 ± ± ± 5 2 ± 3 427 1 1 22 ± 1 1 ± ± 3 ± 2

2 3 ± 1 ± ± 28 2 68 19 ± ± ± 4 4 ± 2 399 1 1 21 ± 1 1 ± ± 4 ± 5

107 37 7 13 4 2 496 133 972 910 9 ± 14 262 143 5 12 5030 10 10 264 ± 41 5 56 ± 234 25 23

494 493 29 99 17 26 6580 626 19360 3930 46 19 57 888 677 41 61 83200 37 127 2060 ± 143 10 325 1 1648 95 175

11.5 <0.3 <0.3 0.14 <100 <0.05 <0.05 <0.35 <0.25 10 <10 <0.07 <0.07 <10 0.26 <0.07 <10 <0.1 1.13 <0.3 <5 <0.5 <0.01 <10 0.038 <0.5 <0.05 <0.01 0.275

Abbreviations as in Table 1; <`number', values below detection limit; ef, enrichment factor. a Background values (median) in mg/litre from Caritat et al. (1998).

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Table 4 Comparison of snow total concentrations (®lter residues plus meltwater) for some selected elements from this study with published data by Caritat et al. (1998). Values in mg/litre Element

Ag Al As Ca Cd Co Cr Cu Fe K Mg Na Ni Pb S V Zn

This study

Caritat et al. (1998)

Monchegorsk (average)

Zapoljarnij (average)

Nikel (average)

C1 (Zapoljarnij)

C2 (Monchegorsk)

0.92 517 40.5 382 10.4 79 10.7 1460 1673 149 371 922 1038 19 2059 18.7 44.4

0.85 1742 32.2 1557 0.81 220 86.6 3716 12155 226 3745 2466 7151 2.7 10963 15.9 52.9

0.8 900 20.7 521 0.75 47.2 53.5 821 6136 178 1717 1486 1241 5.4 2164 12.1 17.9

<0.01(±) 343 (30) 3.7 (12) 420 (4) 0.24 (5) 25 (500) 11 (31) 329 (1316) 4020 (402) 150 (15) 1930 (193) 2220 (222) 701 (7010) 1.8 (6) 2380 (476) 4.8 (96) 12 (44)

<0.01(±) 407 (35) 5.7 (19) 310 (3) 0.41 (8) 79 (1580) 6.6 (19) 691 (2764) 1190 (119) 140 (14) 210 (21) 520 (52) 853 (8530) 8.4 (28) 1007 (201) 34 (680) 17 (62)

Bold values in parenthesis are enrichment factors calculated from data given in Caritat et al. (1998).

shown in Table 4, our average data for all selected elements, except for V in Monchegorsk, are higher than the values published by Caritat et al. (1998). For the smelter in Nikel, no values by the latter authors are available. The enrichment factors have been calculated for snow ®lter residues using data given in Caritat et al. (1998) as the median element value for catchment versus background level. These are mostly lower than 700 when comparing catchments (C1=Zapoljarnij area and C2=Monchegorsk area) close to industry to the background levels (Table 4). However Co, Cu and Ni show enrichment factors up to 8500 (Ni in C2). Our study shows an enormous increase of the enrichment factors for heavy metals and other elements (up to several 10 000±100 000 times, compare Tables 3 and 4), when collecting snow at very short distances from the plants (generally between 1 and 8 km). The position of the samples for all three localities, the distance from the emission sources and enrichment factors for Cu and Ni are shown in Fig. 2. Fig. 3 presents the correlation of enrichment factors with distance from the plant for seven selected elements (As, Cd, Cr, Cu, Fe, Ni, S) and for all three localities (Nikel, Monchegorsk and Zapoljarnij). This is in good agreement with Caritat et al. (1997) who showed that element levels decrease very fast with distance from the source even in the prevailing wind direction. The highest concentrations of these elements were recorded in Z-8 (1.5 km north-east; Fig. 2a), N-15 (1.5 km to the north; Fig. 2b) and M-7 (3.5 km south-east; Fig. 2c). In almost all samples from Nikel and Zapoljarnij Cu/ Ni ratios are low and very constant (0.4±0.6). In the

samples from Monchegorsk the Cu/Ni ratio is generally higher and varies between 0.5 and 1.5. The low Cu/Ni ratio in ®lter residues at Zapoljarnij and Nikel and the higher ratio at Monchegorsk are attributed to di€erences in the composition of the primary ore used (Reimann et al., 1997b). The ore roasting and dressing plant in Zapoljarnij processes local Pechenga ore only, with a Cu/Ni ratio 0.5, whereas the Monchegorsk smelter complex processes Noril0 sk ore (Cu/Ni 2.0) which is mixed in various proportions with material from Pechenga. The smelter in Nikel processes local Pechenga ores which can be mixed in varying proportions (up to 30%) with Noril0 sk ore (Pechenga Nikel Kombinat, personal communication). The contributory factors responsible for higher variation of Cu/Ni ratio in the snow ®lter residues from Monchegorsk are probably smelting technology and processes used in the Monchegorsk smelter complex. The ratio of ®lter residues (FR) to ®lter residue (FR) plus meltwater (MW) is presented as boxplots for all three localities (Zapoljarnij, Nikel and Monchegorsk) in Fig. 4. These are a useful mode of graphic representation of results, originating from exploratory data analysis (Tukey, 1977). The ®lter residue fraction represents a water insoluble form and particulate input of elements (>0.45 mm), whereas the meltwater fraction represents the solute phase (<0.45 mm). Comparison of (FR/(FR+MW)) ratios facilitates distinction between the predominant form of element input into snow, i.e. a low value of this ratio indicates dominance of the solute phase; a high value shows that the particulate phases prevail. Almost all Na occurs in soluble form at all three localities (Fig. 4). Elements such as Ca, Cd, and K are

D. Gregurek et al./Environmental Pollution 102 (1998) 221±232

227

Fig. 2. The enrichment factors for Cu and Ni with respect to the distance from the plants (a) Zapoljarnij, (b) Nikel and (c) Monchegorsk. For explanations see text.

strongly enriched in the meltwater fraction, especially in Monchegorsk and Nikel (Fig. 4a,b). Cr, Al, Ag and Fe are predominantly enriched in the ®lter residue fraction suggesting particulate forms of element deposition. On the other hand Co, Ni and Cu show di€erent trends for Nikel and Zapoljarnij (Fig. 4b,c) and for Monchegorsk (Fig. 4a). Fig. 5 compares element concentration in meltwater and in ®lter residues for Nikel, Zapoljarnij and Monchegorsk in correlation diagrams for six selected elements (Co, Cd, Cu, Fe, Ni and S). A good positive correlation (r2>0.90) between the element content in both fractions can be observed for Ni, Co, Cd and S for all three localities. Cu shows positive correlation for Nikel and Zapoljarnij only; Fe only for Monchegorsk.

Ni, Cu, Co, Fe and partly S are extremely enriched in the ®lter residue fraction, especially at Nikel and Zapoljarnij. A di€erent behaviour of Co, Ni and Cu at Nikel and Zapoljarnij, and on the other hand at Monchegorsk, for example, higher particulate input versus higher solubility (see Figs. 4 and 5), can be recognized. For Ni and Co, median values of the FR/(FR+MW) are 0.45 and 0.4, respectively (Fig. 4a), indicating that 45% of Ni and 40% of Co are in dissolved (solute) form. The extremely enriched Ni, Cu, Co and Fe in Nikel and Zapoljarnij in the ®lter residue fraction (Fig. 5) is a further example of higher particulate emissions for both localities. Results presented in Fig. 4 from Zapoljarnij and Monchegorsk compare well with data published by

228

D. Gregurek et al./Environmental Pollution 102 (1998) 221±232

Fig. 3. The enrichment factor for snow samples from Monchegorsk (M), Nikel (N) and Zapoljarnij (Z), calculated as the element concentration in the snow samples/background, for seven selected elements.

Caritat et al. (1998). However some elements, especially Ni (0.7) and Co (0.6) show a higher proportion of particulates nearer to Monchegorsk (Caritat et al., 1998). For Nikel, no data by the latter authors are available. Di€erent trends for Ni, Cu and Co can be attributed to the di€erences in the smelting and processing technology used at Nikel and Zapoljarnij in comparison to

Fig. 4. Boxplot comparison of the ®lter residues/(®lter residues plus meltwater) ratio for (a) Monchegorsk, (b) Nikel and (c) Zapoljarnij. Elements on the left side are mostly water soluble; elements to the right are deposited in particulate form.

Monchegorsk. The more `primitive' plants at Zapoljarnij and Nikel lose considerable amounts of original ore

D. Gregurek et al./Environmental Pollution 102 (1998) 221±232

229

Fig. 5. XY diagrams for six elements showing correlation between ®lter residues and ®ltered meltwater. Table 5 Platinum group elements (Rh, Pt, Pd), Au and Te content in snow ®lter residues from Kola Peninsula. Values in ng/litre Sample

DL

M-1

M-2

M-3

M-4

M-5

M-6

M-7

Z-8

Z-9

Z-10

Z-11

N-12

N-13

N-14

N-15

Rh Pd Pt Au Te

0.5 1 1 0.1 10

1.0 96 19 6.7 183

0.8 217 62 21.9 507

0.8 71 16 5.6 117

<0.5 33 1.1 3.5 63

<0.5 41 1.3 3.5 73

1.7 204 47 18.5 387

19.0 2770 650 186 3800

1.7 196 88 68.4 5070

<0.5 1.1 8 10.0 600

0.5 65 17 45.8 750

<0.5 7 2 2.8 150

<0.5 <1 <1 0.1 11

<0.5 <1 <1 0.1 14

<0.5 19 2 1.6 193

2.3 187 31 14.2 1800

Abbreviations as in Table 1; <`number', values below detection limit.

230

D. Gregurek et al./Environmental Pollution 102 (1998) 221±232

particles which are not water soluble (particulate input), whereas the more technologically advanced Monchegorsk smelter complex probably emits elements in more soluble form. The higher S content in the ®lter residue fraction in Zapoljarnij provides additional support for the above suggestion, for example, higher particulate input of S caused by the ore roasting and dressing plant at Zapoljarnij. 3.3. Precious metals The precious metals Rh, Pd, Pt, Au have been detected in almost all snow samples (Table 5). Pd and Pt are the most abundant of the PGEs with contents ranging from several to 2700 ng/litre in one sample from Monchegorsk (Gregurek et al., 1997). Generally, contents of precious metals (Rh, Pd, Pt, Au) and Te are distinctly higher in Monchegorsk than in Nikel and Zapoljarnij (Table 5). This is ascribed to di€erences in the primary ore composition. The Monchegorsk smelter complex processes mostly PGEand Au-rich ores from Noril0 sk (Talnakh). The ore roasting and dressing plants in Zapoljarnij process the local Pechenga ores only, with PGEs and Au contents by a factor of 100 lower than in Noril0 sk ore (Boyd et al., 1997). Precious metals (Rh, Pd, Pt, Au) generally show positive correlations (correlation factor, r2>0.95) with each other as well as with Te. However, distinct interceptions can be seen on Pt/Te, Pd/Te and Pd/Au diagrams (Fig. 6). The Pt versus Te correlation diagram shows the same slope for all three localities with Nikel showing almost the same intercept as Zapoljarnij (Fig. 6a). In the Pd/Te and Pd/Au correlation diagrams Nikel occupies an intermediate position between Zapoljarnij and Monchegorsk (Fig. 6b,c). These di€erences can probably be ascribed to changes in ore composition (mixing of local Pechenga ores with PGE and Au rich Noril0 sk ores) fed into the Nikel smelter. 4. Conclusion Snowpack samples were collected at the end of the Arctic winter 1995/96 in the immediate vicinity (1±8 km) of the point-source emitters Zapoljarnij, Nikel and Monchegorsk on the Kola Peninsula, northwest Russia. Two snow fractions, ®ltered meltwater and ®lter residues, were separated by ®ltration (0.45 mm) and analyzed independently using multi-element techniques such as ICP-MS, ICP-AES, ion chromatography for up to 39 elements (Ag, Al, As, B, Ba, Be, Bi, Brÿ, Ca, Cd, Clÿ, Co, Cr, Cu, F, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Sc, Se, Si, Sr, Th, Tl, U, V, Y and Zn). Precious metals (Rh, Pd, Pt, Au) and Te were analysed using GFAAS.

Fig. 6. Correlation diagrams (a) Pt/Te, (b) Pd/Te and (c) Pd/Au showing distinct intercepts for Monchegorsk, Nikel and Zapoljarnij. Explanation in text.

Highly elevated levels have been observed for most elements in the ®ltered melt water and ®lter residues from Nikel, Zapoljarnij and Monchegorsk. Compared to background levels in snowpack samples from Finland (Caritat et al., 1998), enrichment factors for heavy metals and other elements deposited on snow, are in the range of 10 000±100 000.

D. Gregurek et al./Environmental Pollution 102 (1998) 221±232

The higher element levels for Zapoljarnij compared to Nikel and Monchegorsk can be attributed to the combination of two anthropogenic sources (i.e. smoke stack emission from the ore roasting plant and dust from the open-pit). The Cu/Ni ratio and the correlation between the precious metals (higher Pt/Pd ratio in Pechenga ores and, thus, in Zapoljarnij) assist in ®ngerprinting of the primary ore components used and facilitate distinction between Pechenga and Noril0 sk ores. Changes in the ore composition (mixing of both ore components) can also be observed. The comparison of the trace element concentrations of the ®lter residues (particulate form) and ®lter residues plus meltwater (total loading of elements), expressed as the FR/(FR+MW) ratio, provides information on the predominant input form of elements to the snow. The FR/(FR+MW) ratio thus emerges as a suitable method for the investigation of local emission sources. The amount of chemical information to be obtained from the snow of one winter has exceeded our expectations. Base and precious metal ratios open up new avenues for the identi®cation of ores and processes used by industrial emitters. We consider the methods and results reported in this note relevant for, and applicable to, environmental monitoring of mining and metallurgical activities not only in the Arctic and Sub-Arctic, but at all latitudes with regular winter snow cover. Acknowledgements We are grateful to Vladimir A. Pavlov (Central Kola Expedition, Monchegorsk) for sample collection and to Heikki Niskavaara (Geological Survey of Finland, Rovaniemi) for analytical data. Constructive discussions with Frank Melcher (MU, Leoben), who also critically read the manuscript, are greatly appreciated. Hassan Neinavaie (GEOOÈKO, Eisenerz, Austria) is thanked for discussions. The manuscript was signi®cantly improved by critical comments of two anonymous reviewers. D. Gregurek is supported by Austrian Science Fund (FWF, Vienna) Grant No. 11983-CHE to E.F. Stump¯. The Norwegian participation was ®nanced by the Norwegian Ministry of the Environment and the Geological Survey of Norway. References AÈyraÈs, M., Reimann, C., 1995. Joint ecogeochemical mapping and monitoring in the scale of 1:1 million in the west Murmansk region and contiguous areas of Finland and NorwayÐField handbook. Norges Geologiske Undersùkelse Report 95.111. AÈyraÈs, M., Caritat, P. de, Chekushin, V.A., Niskavaara, H., Reimann, C., 1995. Eco-geochemical investigation, Kola Peninsula: sulphur

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