Present environmental state survey of the Eno and Kontiolahti claim areas, Finland

Transkriptio

1 Geologian tutkimuskeskus Kuopio Public /2013 Dnro K555/52/2006 AREVA NC (COGEMA) Present environmental state survey of the Eno and Kontiolahti claim areas, Finland Markku Tenhola, Jouko Saarelainen ja Maria Nikkarinen

2 Geologian tutkimuskeskus Contents Documentation page 1 INTRODUCTION Location, environment and infrastructure of the Riutta area 1 2 PREVIOUS STUDIES Exploration Geochemical studies Regional geochemical lake sediment mapping Regional geochemical till mapping Radiometric environmental studies at Paukkajanvaara and Riutta (STUK) Other previous studies 12 3 SAMPLING AND CHEMICAL ANALYSIS Water samples Organic samples (stream- and lake sediments, mosses) 15 4 PRESENT GEOCHEMICAL STATE OF THE RIUTTA AREA Bedrock Quaternary deposits Nature types and forestry Present state of surface and groundwater Flow conditions of surface and groundwater Physical properties of water samples Results of the radiometric determinations in water samples Present state of the lake and stream sediments and mosses Radiometric determinations in lake and stream sediments and moss samples Results of the chemical analysis 25 5 SUMMARY 28 6 REFERENCES 30 7 APPENDICES 32

3 Geologian tutkimuskeskus 1 1 INTRODUCTION The Geological Survey of Finland (GTK) has drawn up an environmental baseline study for the mining company AREVA NC (COGEMA) concerning claim areas (17 claims, a total of 1527 hectares) in the municipalities of Eno and Kontiolahti. The purpose of the exploration is to find economic uranium ore deposits in the area. The baseline study comprises chemical analysis of surface water (stream and lake), groundwater, sediments (stream and lake), soil as well as mosses. Geochemical sampling was carried out at the end of August and Quaternary mapping at the end of September Quaternary mapping in the scale 1:5 000 was done according to the standards used in GTK. At the same time with the Quaternary mapping observations were made upon the flowing directions of surface waters. The boundaries of the drainage areas are based on field observations and map interpretation. Also landscape and landforms, forest types, vegetation and conservation and Natura areas are described. In the issues of radiometric studies the Radiation and Nuclear Safety Authority (STUK) was consulted. Earlier works concerning geological and geochemical studies made by GTK and STUK were utilized. The client of this present base line study is AREVA NC (COGEMA), whose representative in the project is Philippe Crochon. The representatives of the GTK are environmental geochemist Markku Tenhola, environmental geochemist Maria Nikkarinen and Quaternary geologist Jouko Saarelainen. As a consulting specialist, familiar with the previous uranium exploration, is geologist Olli Äikäs. 1.1 Location, environment and infrastructure of the Riutta area The Riutta study area (Fig. 1) is situated in eastern Finland about 30 km NE of Joensuu in the municipalities of Eno and Kontiolahti. The claim areas are 4.5 to 8 km west and northwest of the village Eno with c inhabitants. The land areas at Riutta are owed by several private landowners and companies. A gravel pit (Kuvassärkkä) is situated close the main road in the southern part of the claim area and a macadam quarry one kilometer northeast of the gravel pit (both places are marked with green symbols in the map showing drainage areas, Appendix 3). A groundwater pumping station has been constructed in a former sand pit ca 800 m south of the Kuvassärkkä gravel pit. From the main road in the south, a forest road runs to the north past the pumping station, connecting the area to the road between Riutta and Kyykkä. This connecting road is a popular and much used shortcut from the northern areas to the main road. These activities have increased the traffic in the connection road, and also the amount of dust to the environment. At Kankikoski, about 600 m west from the pumping station, there is a fish breeding company. In the close vicinity of the Riutta occurence there is no settlement, but on the shores of lake Riuttalampi, 1-2 km apart from the occurence, there are summer cottages and two farming houses (possibly used as summer residences presently). In the northwestern part, 1.5 km from the border of the claim Eno-1, there is an environmental protection area Kolvananuuro, a SE-NW striking gorge with its old forests (Fig. 1). Kolvananuuro and two smaller areas nearby belong to the Natura protection programme. A popular trekking route from Joensuu to Koli transects the NW part of the claim areas Kontiolahti-1. A mining concession by Keramia Oy (presently an open pit for mining kyanite and andalusite-

4 Geologian tutkimuskeskus 2 bearing rock) is situated c. four kilometers northwest of the claim Eno-1, only 900 m SW from the Kolvananuuro protection area marked in Fig. 14. Fig. 1. Location of the Riutta study area

5 Geologian tutkimuskeskus 3 2 PREVIOUS STUDIES 2.1 Exploration Since the discovery of the Riutta ore boulders in 1958, uranium exploration has been carried out in the area, at first by Atomienergia Oy ( ) and later on ( ) by Outokumpu Oy (Huhma 1963). The two companies carried out boulder tracing, ground geophysics and seismic studies and radon surveys. At that time, also, geological mapping was carried out in the whole area from Riutta to Koli. The companies drilled 32 diamond drill holes at the Riutta prospect (Fig. 2). In spite of numerous rich boulders discovered and mapped by the companies, the results of the drillings were poorer than expected. Fig. 2. Location of the diamond drill holes of Atomienergia Oy, Outokumpu Oy and Geological Survey of Finland, uranium-bearing boulders and recovered research pits (excavator) in the claim areas at the Riutta prospect. The base map: National Land Survey of Finland, licence 13MYY/2007.

6 Geologian tutkimuskeskus 4 In 1983 the exploration department of GTK launched an exploration project at Riutta including airborne geophysical survey, geological mapping, pedogeochemical sampling (with percussion drills), quaternary studies (e.g. trenching), radon surveys and peat geochemistry. The Unimonttu occurrence was drilled in A total of 24 drill holes (1215 m) were drilled at this site. The claim report was delivered to the Ministry of Trade and Industry in 1989 (Äikäs 1989). Imprints of the previous exploration works on the Riutta prospect are visible at a few restricted sites. At Ristimonttu Atomienergia Oy stripped the bedrock in an area of a few acres with a bulldozer in 1958 and 1959 (Fig. 3 and 4). A trench was blasted in the bedrock in order to get samples for test milling (which was carried out at the then active Paukkajanvaara test plant in Eno). The workings at Ristimonttu have not been restored. There are still blocks of mineralised rock (impregnations of pyrite & veins of pitchblende) in the trench and around the trench. Fig. 3. Location of the sites for the past detailed exploration at the Riutta prospect, from the north: the Ristimonttu pit, the Unimonttu pit (backfilled) and the Fan-3 trenching site. The coordinates from south to north are 200 m apart. The base map: National Land Survey of Finland, licence 13MYY/2007.

7 Geologian tutkimuskeskus 5 Fig. 4. The Ristimonttu occurrence, photographed from the west (left) and from the east (right). Some of the blocks of rock by the trench contain veins of pitchblende. A stagnant shallow pool of water exists on the bottom of the trench most part of the year. The Unimonttu trench (Fig. 5 and 6) was re-opened twice by GTK in the 1980s and backfilled with the same till that was at the site. The present state of the backfilled Unimonttu is approximately the same as before Atomienergia Oy made the first trenches in the 1950s. Some radioactive boulders and chips, originally contained in the till, can still be found at this backfilled site and in the surficial till along the boulder fan from this site to the southeast.

8 Geologian tutkimuskeskus 6 Fig. 5. The Unimonttu trench & drilling grid. Upper right: map of the exposed lithology on the bottom of the pit; lower left, photograph of the final stage of the exposure work in the pit. The spacing of the GTK drill hole sections (upper left) is 25 m. Fig. 6. The Unimonttu trench, open in 1988 and backfilled in 1989, looking NW along the direction of glacial transport. The forest was previously cleared by the landowner, not by GTK.

9 Geologian tutkimuskeskus 7 West and southwest of the Unimonttu site there are five diamond drilling collars of GTK (drill holes 321 and ) still visible at the surface of the valley fill sand (Fig. 7). The hole 326 has been used for water sampling in this study. Fig. 7. Collars of drill holes R324 and R325 of GTK at Riutta in At the Kolmosviuhka site (Fan-3) there are two trenches of Atomienergia, which have not been covered (Fig. 8). In addition, there are a few shallow stripping trenches made by the GTK, which were left open, but which are presently covered by moss and other vegetation. Pitchblende veins are visible in a few outcrops or exposures. The forest is presently totally felled at this site by the landowner. In addition to the imprints described from the three targets above, there are collapsed small pits (foxholes) along the length of the boulder train (Fig. 2) in places where the prospectors of the 1950s had to dig for the subsurface radioactive boulders in the till. The company Atomienergia Oy constructed about 2 km road from the south to the Ristimonttu site. This road served as the basis for the present road that crosscuts the area from the south to the north, across the river Kuusoja. No other traces of the past exploration can be found in the Riutta area.

10 Geologian tutkimuskeskus 8 Fig. 8. Kolmosviuhka (Fan 3) trenches & drilling grid. Upper left: drill holes of Atomienergia Oy and GTK; the dashed line (d) shows the extent of the valley fill sand cover in the west against the till cover in the east. The detailed trench lithology map (upper right) shows natural outcrops (a), remains of the Atomienergia trenches of the 1950s (b) and backfilled GTK trenches (c) from the 1980s. Drilling grid of GTK is 25 m. 2.2 Geochemical studies Regional geochemical lake sediment mapping Regional lake sediment survey was carried out in Finland between using sampling density of 1 sample/4-5 km 2 (Tenhola 1988). The Riutta area is situated in a large, slightly anomalous zone, extending from Eno to the village of Koli (Appendix 4). Highest uranium concentrations exist in the Proterozoic quartzite belt north from the village Koli (1320 ppm) and in the Archaean granite gneiss area on the eastern side of lake Pielinen (1030 ppm). In lake Riuttalampi the uranium concentration was 15 ppm and in Urkkalampi 11 ppm. In the Riutta claim area uranium concentrations are 2-5 times higher than the median value in Finland (3 ppm, Tenhola 1988). All the regional lake sediment concentrations were determined from ignited samples as was customary at the time Regional geochemical till mapping Six sampling sites of the regional geochemical till sampling (1 sample/ 4 km 2, Salminen 1995) are situated in the Riutta claim area. Results are presented in Table 1 and the location of samples

11 Geologian tutkimuskeskus 9 in Fig. 9. Uranium concentrations are generally over 20 times higher than in average in Finland. Highest uranium concentration (171 ppm, sampling site 90419) is found c. 300 m east from lake Riuttalampi. Also, As, Cu and Ni concentrations are slightly higher at Riutta than in average in Finland, whereas Cr, Fe, Th, V and Zn concentrations are lower. Table 1. Element concentrations in till samples situated in the study area. Data is based on the regional till mapping with a density of 4 samples/ 1 km 2 (Salminen 1995). Sampling As Co Cr Cu Fe Mn Ni Pb Th U V Zn site ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm Median in Finland Radiometric environmental studies at Paukkajanvaara and Riutta (STUK) Previous radiometric environmental studies made by STUK ( ) were concentrated in the Paukkajanvaara area in the zone between lakes Ylä-Paukkaja and Hirvilahti (bay of Lake Pielinen, Fig. 1). The aim of these studies was to study the spreading of radioactive elements to the water system as a result of the mining activity at the end of 1950s. Due to the similarity of nature and geology, Riutta area was chosen as reference area for the studies at Paukkajanvaara. In the Riutta area organic stream sediment, lake sediment and water samples were collected from the rivers Riuttapuro, Kuusoja, Matarinsuo and Salmilammenpuro as well from lakes Riuttalampi and Urkkalampi (Sillanpää et al. 1989, Mustonen et al. 1989). The results concerning radionuclide concentrations are presented in Table 2 for organic sediments and in Table 3 for water samples. The sampling sites are presented in Fig. 9. Water analysis were filtered (45 µm) and acified in the field and analysed after nitric acid and hydrochoric acid leach (total analysis). We can see the disequilibrium in the U chain between different sampling sites due to preferential fixation of U in organic sediments. Lake sediment samples, collected in 1985 and 1986 in lakes Riuttalampi and Urkkalampi, were taken with a 5 cm depth interval (7 samples in one profile, Sillanpää et al.1989). Uranium (U- 238) concentrations were low, Bq/kg in Riuttalampi and Bq/kg in Urkkalampi (Table 2). In both lakes the uranium concentrations diminish evenly towards the sediment surface. The highest U-238 concentration (500 Bq/kg) was found in river Kuusoja c. 500 m to the north from the Riutta mineralization. The uranium concentrations in lake Riuttalampi and lake Urkkalampi are times lower than in lakes Hiisilampi and Pieni Hiisilampi near the Paukkajanvaara mineralization (Sillanpää et al. 1989). Lake sediment samples were analysed after leaching with a mixture of nitric acid and hydrochoric acid (total analysis).

12 Geologian tutkimuskeskus 10 In the water sample, collected from the river flowing through the mire Matarinsuo, natural uranium content (2.1 μg/l) was much higher than elsewhere in the area (Table 3). In the sampling site 8, situated close to the Riutta mineralization, total alpha concentration was elevated (0.21 Bq/l). Sampling sites of the stream sediment, lake sediment and water samples are presented in Fig. 9. Fig. 9. Sampling sites of stream water, stream- and lake sediments (STUK ) and till samples (GTK 1984).

13 Geologian tutkimuskeskus 11 Table 2. Radionuclide concentrations in lake- and stream sediments in at Riutta determined by the Radiation and Nuclear Safety Authority (STUK, Sillanpää et al. 1989). Total analysis (see page 9). Sampling sites are presented in Fig. 9. Sampling site Sampling depth in sediment, cm Organic carbon % 238 U Bq/kg 235 U Bq/kg 226 Ra Bq/kg 228 Th Bq/kg 210 Pb Bq/kg 210 Po Bq/kg 1 Lake Riuttalampi Lake Urkkalampi River Riuttapuro River Urkkalamminpuro River Kuusoja River Kuusoja River from Matarinsuo River Kuusoja River Kuusoja River Salmilamminpuro River Kuusoja Table 3. Radionuclide concentrations in lake- and stream water in at Riutta determined by the Radiation and Nuclear Safety Authority (STUK, Sillanpää et al. 1989). Total analysis after filtration (see page 9). Sampling sites are presented in Fig. 9. Sampling site ph Total α 238 U 234 U / 238 U l 226 Ra 210 Pb 210 Po Natural U Bq/l Bq/l Bq/l Bq/l Bq/l Bq/l μg/ l 1 Lake Riuttalampi 7.1 < < Lake Riuttalampi 6.5 < < Lake Riuttalampi Lake Urkkalampi River Urkkalamminpuro 6.8 < < River Urkkalamminpuro - < < River Kuusoja < River Kuusoja River Kuusoja 6.8 < < River from Matarinsuo River Kuusoja 6.4 < < River Kuusoja River Kuusoja 6.6 < River Salmilamminpuro 6.4 < River Kuusoja 6.3 < < U

14 Geologian tutkimuskeskus Other previous studies In the Paukkajanvaara area GTK has done studies, which deal with uranium concentrations in soil (Björklund 1978). Exploration works at Riutta have been described e.g. in the reports by Huhma (1963), Nenonen (1983), Ruotsalainen (1983), Salonen (1983) and Äikäs (1989). Groundwater studies in Palokangas and Kuokkasenkangas areas, are presented in a report by Ahtiainen and Naakka (1993). A report concerning land use and planning in the Itä-Uusimaa and Eno reservation areas is given by Tyynismaa (2005). Geological Survey of Finland collected in 2001 two surface water samples from the Riutta area. One water sample was taken from a pool approximately at the Ristimonttu occurrence and another sample from river Kuusoja near the mineralization. Uranium concentration was 12.2 µg/l in the pool and 1.4 µg/l in river Kuusoja. Enrichment of uranium in peat has been studied in Matarinsuo c. one kilometer west from the Riutta occurrence (Äikäs et al. 1994, Fig. 10). Uranium contents (contents in ash) of up to 2.3 % were found in the peat. According to the writers young uranium is loosely held in its deposits, and in a changing environment may be remobilized posing a danger to water reservoirs downstream. The effect of the radioactive spring can be noticed in one water sample collected from down stream of the river flowing through the mire Matarinsuo. In that sample taken by the STUK (sampling site number 10) natural uranium content was 2.1 μg/ l (Table 3, Fig. 9). Fig. 10. Location of the mire Matarinsuo, Matari spring and their drainage area after Äikäs et al. (1994).

15 Geologian tutkimuskeskus 13 3 SAMPLING AND CHEMICAL ANALYSIS 3.1 Water samples Water sampling was carried out at the last week of August In all 16 water samples were collected; 6 samples from the rivers, 3 samples from the lakes and 7 groundwater samples (Fig. 11). Three groundwater samples were taken from drilled wells in the vicinity of municipal pumping station and two samples from dugwells (Fig. 12 and the cover page of this report). In addition two groundwater samples were collected from a drill hole at the depths of 9 and 24 m (Fig. 12). Fig. 11. Sampling sites of lake sediment and water, stream sediment and water, groundwater and moss samples collected by GTK in August 2006 in the Riutta area.

16 Geologian tutkimuskeskus 14 a b c d Fig. 12. a) A dugwell with electric pump for household water. Typical well is also presented in the cover picture of this report b) Pumping of groundwater from a drill hole, c) Traditional Finnish rowboat used in the sampling in lake Riuttalampi, d) Limnos-type sampler and undisturbed lake sediment sample taken from lake Riuttalampi. The sediment is coloured by Fe 2+ sulphides (dark sediment) to the depth of 25 cm. Four stream water samples were taken from Kuusoja river and one sample from Riuttapuro river. One sample was taken from a river flowing close to the Matari spring (sampling point 14, Fig. 11). Lake water samples were taken from three lakes (Riuttalampi, Urkkalampi and Pikku Urkkalampi). The samples were taken with a Ruttner-type sampler about 1 m above the lake bottom, except in lake Pieni Urkkajärvi, where the water sample was taken from the surface, 0.5 m depth. Rutner type sampler was also used in groundwater sampling from the wells. Temperature, ph (ph 320/Set-1), redox (ph 340i /Set), electric conductivity (LF 330/Set), oxygen content and its saturation degree (Oxi 330/Set) were determined in the sampling site. The same variables were determined also in the laboratory. The sampling was carried out by certified field persons. Water samples were taken into two 100 ml and two 500 ml polyethene plastic bottles (Fig. 13). One 100 ml sample was acidified in the field with 0.5 ml suprapur HNO 3 for total analysis (acid soluble elements), and the other 100 ml sample was untreated, and was sent to STUK for radio-

17 Geologian tutkimuskeskus 15 metric determinations. These samples were filtered (0.45 μm) and acified (HNO 3 ) later in the laboratory of STUK. For cation analysis the 500 ml sample was settled down 4-5 days in the laboratory, after which 100 ml was separated from it, filtered (0.45 μm) and acidified with 0.5 ml suprapur HNO 3. Anion determinations as well as total nitrogen and carbon determinations were made from another 500 ml sample. a b Fig. 13. a) Stream water sampling, in which water sample is filtered into the 100 ml plastic bottle, and b) Stream sediment sampling using a nylon net. All water samples were analysed by a combination of ICP-MS and ICP-AES methods. Anion determinations were made using IC technique and alkalinity by titrimetric method. Total alfa activity and Radium-226 were determined in STUK. All chemical analysis and physical determinations were made in accredited laboratories of GTK and STUK. 3.2 Organic samples (stream- and lake sediments, mosses) Organic stream- and lake sediment samples were taken at the same time and at the same sites than the water samples. Altogether 15 samples were collected from which 5 were stream sediments, 5 lake sediments and 5 mosses. Organic stream sediments samples, consisting of 5 subsamples, were collected over a distance m, to ensure that they were sufficiently representative. In order to obtain pure organic material, nylon net (Fig. 13) was used for scooping unconsolidated sediment from streams, and samples were subsequently decanted so that mineral particles could be removed by settling (Räisänen et al. 1992). Lake sediment samples were taken from three lakes, 3 from Riuttalampi, 1 from Pikku Urkkalampi and 1 from Urkkalampi. From lake Riuttalampi samples were taken from the depths of 0-15 cm, cm and cm. From lakes Urkkalampi and Pikku Urkkalampi the samples were taken from the uppermost part of the sediment. Lake sediment samples were taken with a Limnos-type sampler, which makes possible to get undisturbed sediment from the upper part of the sediment column and split it into 1 cm thick slices (Fig. 12). Stream sediments, lake sediments and mosses were dried using lyophilisation including prefreezing, crushed with a cutting mill and sieved < 2 mm fraction. Samples were leached with nitric acid using microwave oven technique (EPA Method 3051) and analysed by a combination of ICP-MS and ICP-AES methods. C and N were analysed by C-N analyser. Gammaspectrometric

18 Geologian tutkimuskeskus 16 determinations for radium-226 and other radionuclides were made in STUK. Using long measuring times (1-3 days) it was possible to detect, with high uncertainty, also Pb-210, U-238, Th-228, K-40 and Cs-137 contents. Terrestrial moss species collected was Hylocomium splendens. Three uppermost shoots were taken for the analysis. Like stream sediment samples also terrestrial moss samples were composite samples of 5 sub-samples, collected from an area of one hectare. Sampling sites are situated close the Riutta mineralization and over the large boulder fan extending approximately 3 km to the southeast (see Fig. 2). Sampling sites for each sample media are presented in Fig PRESENT GEOCHEMICAL STATE OF THE RIUTTA AREA 4.1 Bedrock Bedrock at Riutta is composed of Archaean ortho- and paragneisses, overlain by Paleoproterozoic (Jatulian) quartzitic metasediments (Fig. 14). The southwestern part of the area comprises Fig. 14. Lithology of the bedrock in the claim application area at Riutta. Concession and Natura conservation areas are marked in the picture. The map is modified after Kohonen & Vuollo (2000).

19 Geologian tutkimuskeskus 17 a basement window (part of the Kontiolahti Dome). Eastern and western parts of the area are mainly gneissose granodiorite and porphyritic granites. The zone of Archaean supracrustal rocks extends from Riutta some five kilometers to Kuusjärvi. The Riutta uranium occurrence, with pitchblende veins, is hosted by sericite-quartz schist in the contact zone between the Proterozoic schists and Archaean gneisses. These rocks are cut by mafic dykes of Proterozoic age, probably 2.2 to 2.1 Ga. More detailed descriptions of the rock types in the Riutta area are given in Piirainen (1968), Kohonen & Marmo (1992), Laiti (1983) and Kesola (1998). 4.2 Quaternary deposits The Riutta area and the Kuusoja valley, as a whole, are situated in the marginal zone of an ice sheet, that withdrew approximately years ago (Fig. 15). Melting of the ice sheet in this area was complicated. The older ice flow, before the last stage of melting, has moulded the terrain and left striaes and grooves on the surfaces of bedrock trending approximately between o. Uranium-bearing boulders have been transported in the same direction. Fig. 15. The Pielisjärvi ice-marginal formation at Kuusoja after Rainio (1990). The paleogeographic situation at the final stage of glaciation. The last direction of the continental ice sheet flow was almost from the west. The Yoldia Sea, or the glacial lake at a slightly higher elevation, filled the valley up to the level of 105 m.

20 Geologian tutkimuskeskus 18 The latest ice lobe proceeded from the west towards the Kuusoja valley. In the valley the margin of the ice extended to a bay of and the ice lake, which was situated 120 m above the present sea. Between the ice lobe and the bay an end moraine formation was deposited (Appendix 1). It formed from till, sand and gravel materials washed and transported by the melting waters of the ice. Finally the valley was filled with the sorted material to the level of the sea of that time. Thickness of the sorted material may be several tens of meters. At the eastern part of the area the ice melted slowly in situ. Till is the most common type of overburden in the area. Till is soil material dislodged from the bedrock and transported by the ice. Distribution of the uraniferous boulders shows well the transport direction of the glacial drift (Fig. 2). At the bottom of the ice sheet the till material became more tightly packed and formed ground moraine (basal till). Basal till covers the bedrock in varying thicknesses throughout the area. In general, the basal till is a sandy till with low clay content (< 5%) and low content of fines (< 30%). In the eastern part of the area also fine grainedtill exists with clay content > 5% and fines > 30 % (Appendix 1). 4.3 Nature types and forestry Landscape in the Riutta area is hilly with varying topography. The last glaciation has molded the scenery and caused northwestern- southeastern orientation. Typical landforms are deep rupture valleys formed in the shear zones of bedrock. These valleys are filled with sand and gravel as in the Kuusoja Valley. In the western part of the area, where the bedrock is covered by till and where the outcrops are common, coniferous forests (e.g. spruce) and deciduous forests (e.g. birch) as well as mixed forests are most common (Appendix 2). In the middle part of the area (ice-marginal formation) pine forests prevail. In the east, most luxuriant forests exist in the nutrient-rich fine-grained till (clayrich) areas, with an exception of small river valleys. Areas cultivated by clearing and burningover woodland are distinguished as patches in the map (Appendix 3) and are characterized by deciduous forests. Forest site types presented in Appendix 2 are based on the classification used in Finland. Most common forest type is Oxalis-myrtillus type (OMT) found especially in the eastern and western parts of the study area (till areas). OMT-type is characterized by coniferous forests (mainly spruces) or mixed forests. In these areas, especially in fresh moors, also Vaccinium-rubus type (VRT) is widespread. The second common forest site type is Vaccinium myrtillus type (VMT) found in the sand and gravel-bearing areas of the ice-margin formation. Also, in these areas Vaccinium forest type (VT) exist, especially in dry moors. Forest site types Geranium-oxalismyrtillus (GOMT) and Geranium filipendula (GfiT) exist in wet and moisture areas in the valleys and in the slopes of the hills, and also in the nutrient groves together with high grown grasses. Peat bogs in the area are mainly muskegs and aapa bogs. They developed by the paludification of wet valley floors or by overgrown of small lakes and ponds, as examples lake Pieni Urkkalampi and the surroundings of lake Mustalampi. Most peat bogs in the area are drained and fertilized.

21 Geologian tutkimuskeskus Present state of surface and groundwater Flow conditions of surface and groundwater The Riutta study area and the Kuusoja valley belong to the Kuusoja drainage area with a discharge to river Pielisjoki in the south (Appendix 3). From Pielisjoki the waters flow via the town of Joensuu to lake Pyhäselkä (Fig. 1). The size of the Kuusoja drainage area is 102 km 2, from which 4.5 % is covered with lakes. According to the data from the North Karelia Regional Environment Centre, the amount of precipitation in September 2006 was mm. In average in September between the amount of precipitation in the Eno area was mm. In October the amount of precipitation was greater ca mm, exceeding times normal values. According to the estimates of the North Karelia Regional Environment Centre, the discharge of water runoff in North Karelia at the end of summer 2006 was only 2-6 l/s, due to a very dry summer. The end of October and the beginning of November were rainy causing higher values of water discharge, l/s. Annual precipitation in the area has been in recent years mm, but in a very rainy summer 2004 annual precipitation was even over 850 mm. Boundaries of the drainage areas, flow directions of surface waters, surface water runoff and discharge (l/s) in streams are presented in Appendix 2. In the eastern and southern parts, also smaller drainage areas situated within the Kuusoja drainage area are presented. Surface waters in the Kuusoja valley (approximately the area of ice marginal formation composed mainly of sands, Fig. 15) run along several natural channels to river Kuusoja and further to river Pielisjoki. The surface water runoff is most effective in till and bedrock areas due to the small number of rivers. In the area of ice-marginal formation surface water is seeping effectively downwards and form groundwater. Most important discharge channels to Kuusoja are river Urkkalamminpuro (running from lake Urkkalampi), river Riuttapuro (from lake Riuttalampi), in the west river Salmilamminpuro (flowing close lake Mustalampi), river Kalattomanpuro (in the southwestern part of the area) and river Kurvisenpuro in the east. Runoff of water was very low and most small rivers were dry during the sampling period in August Due to this, many springs and wells were dry causing difficulties in water sampling. Three separate groundwater reservoirs are situated in the Kuusoja valley (Appendix 3). These are classified as important groundwater supplies by the North Karelia Regional Environment Centre. The precipitation in the Kuusoja valley produces groundwater approximately 8500 m 3 /day. The pumping station of the Eno municipality is situated in the southernmost reservoir producing groundwater 700 m 3 /day. A lot of groundwater flows from the surrounding hills to the valley. The groundwater flows mainly by seeping into the lakes and to the fractures of the underlying bedrock. In the Palokangas area groundwaters flow partly southwards to river Salmilamminpuro and partly eastwards to river Kuusoja (Appendix 3). In the Kuokkasenkangas area groundwaters flow mainly southwards to river Kuusoja and, also, to the northwest towards lake Valkealampi (Ahtiainen and Naakka, 1993). According to the report of the Road Office (Savo-Karjala Road District) the flowing direction of groundwater in the area of Kuvassärkkä (see Chap. 1.1) is towards west.

22 Geologian tutkimuskeskus 20 It is probable, that the groundwater areas form several separate basins due to thresholds in the bedrock. In this report no studies have been made concerning the structure of the bedrock (e.g. shear zones), which control the movement of the groundwater Physical properties of water samples In drilled wells ph values (measured in laboratory) varied between and in dugwells between (Table 4). The values are lower than Lahermo et al. (2002) have presented as Table 4. Temperature, ph, redox, electric conductivity (EC), oxygen concentration (mg/l) and oxygen saturation degree (%) in dugwells (dug into the overburden), drilled wells (drilled into the bedrock), drill holes, lake water and stream water determined in field and in laboratory. Sampling was carried out in August Sampling sites are presented in Fig. 11. Sampling site Type Depth T o C ph Redox EC O 2 O 2 saturate mv us/cm mg/l degree (%) Determinations in field Well-1 Drilled well Well-2 Drilled well Well-3 Dugwell Well-4 Dugwell Clear Well-6 Drill hole 9 m Clear, greyish Well-6 Drill hole 24 m Well-7 Dugwell Lake-5 Lake water 19 m , Lake-8 Lake water 5.6 m Lake 15 Lake water 1 m Water-9 Stream water Water-10 Stream water Water-11 Stream water Water-12 Stream water Water-13 Stream water Water-14 Stream water Determinations in laboratory Well-1 Drilled well Clear water Well-2 Drilled well Clear water Well-3 Dugwell Clear water Well-4 Dugwell Clear water Well-6 Drill hole 9 m Slightly yellowish Well-6 Drill hole 24 m Slightly yellowish Well-7 Dugwell Slightly yellowish Lake-5 Lake water 19 m Slightly yellowish Lake-8 Lake water 5.6 m Brownish Lake 15 Lake water 1 m Yellowish Water-9 Stream water Clear, slightly yellowish Water-10 Stream water Clear, slightly yellowish Water-11 Stream water Clear, slightly yellowish Water-12 Stream water Clear, slightly yellowish Water-13 Stream water Clear, slightly yellowish Water-14 Stream water Clear, slightly yellowish

23 Geologian tutkimuskeskus 21 medians in Finland (for drilled wells ph 7.2 and dugwells 6.4). In drill hole samples ph varied between The lowest ph value (5.98) was found in the water from the groundwater pumping station. In stream water samples ph values ( ) were higher than in groundwater. In all samples (three samples) taken from the groundwater area, redox-values and oxygen amounts were high. In the same samples the values of electric conductivity were low. Rapidly flowing river waters have high oxygen contents and redox values (sampling sites 10-14, Fig. 11). Although the water in lake Riuttalampi is dark coloured, indicating reducing conditions, its redox value (depth 19 m) was high (302 mv). Redox values (112 and 130 mv) and oxygen amounts (48 and 50 %) were lower in the drill hole samples than in other groundwater samples. In general, EC values in groundwater and surface water were quite close to each other, which may due to the fixation of ground- and suface waters. Values of physical properties, measured in the laboratory, were close to those measured in the field. However, the ph value in the drill hole (depth 9 m) was 7.2 in the field, but only 6.3 in the laboratory. In the samples collected from groundwater areas (1-3) the water was very clear, whereas, the water in drill whole samples was slightly grayish (Table 4) Results of the radiometric determinations in water samples Total alpha and Ra-226 determinations were made from 16 water samples comprising samples from lakes, rivers and groundwater from dugwells and drilled wells and two samples from a drill hole (depths 9 and 24 m, Table 5). In the surface and groundwater samples most total alpha activities and radium-226 concentrations were below the detection limit (for total alpha <0.02 Bq/l and for radium-226 < 0.01 Bq/l). In the drill hole, close the Unimonttu mineralization, the total-alpha activities (0.15 and 0.53 Bq/l) were some tens times higher than the background value (<0.02 Bq/l). Also, Ra-226 concentrations ( Bq/l) were higher in two drill holes than elsewhere. Slightly elevated total alpha activities existed in the river in Matarinsuo (0.07 Bq/l) and in a dugwell in the northern part of lake Riuttalampi (0.06 Bq/l, sampling site 7, Fig. 11). Total alpha and Ra-226 values in stream and lake water samples were close the values determined in the Riutta area in (Table 3). Regional distribution of total alpha concentrations is presented in Fig. 16. In this figure the data from (STUK) and 2006 (GTK) are combined. Highest concentrations are close to the Unimonttu occurrence in the drill hole and in Kuusoja stream water flowing nearby. It should be emphasized that the stream water sample from the river was collected earlier by STUK than the drillings were carried out in 1988 by GTK.

24 Geologian tutkimuskeskus 22 Table 5. Total alpha activities (Bq/l) and Ra-226 concentrations (Bq/l) in lake, river and groundwater samples (dugwell, drilled well, drill hole) in the Riutta area collected in August Sampling sites are presented in Fig. 11. Sampling site Type Total-alpha activity, Bq/l 226 Ra, Bq/l 1 Drilled well, pumping station <0.02 < Drilled well <0.02 < Drilled well < Dugwell 0.02 < Lake water, Riuttalampi 0.03 < (9 m) Drill hole (24 m) Drill hole Dugwell 0.06 < Lake water, Urkkalampi 0.04 < Kuusoja river 0.03 < Riuttapuro river <0.02 < Kuusoja river <0.02 < Kuusoja river <0.02 < Kuusoja river < River (spring) Matarinsuo 0.07 < Lake water, Pikku Urkkalampi <0.02 <0.01

25 Geologian tutkimuskeskus 23 Fig. 16. Total alpha concentrations in stream, lake and groundwater. Results from the studies in (STUK) and 2006 (GTK) are combined. Red dots represent concentrations in groundwater (see Fig. 9 and 11).

26 Geologian tutkimuskeskus Present state of the lake and stream sediments and mosses Radiometric determinations in lake and stream sediments and moss samples Lake sediment, stream sediment and moss samples Radiometric determinations in lake and stream sediments and moss samples are presented in Table 6. As mentioned before, long radiating times (1-3 days) were needed due to low concentration levels. Especially the uncertainty for Pb-210 determinations was remarkable. In Riuttalampi, at the sampling site P5, Ra-226 concentrations varied between Bq/kg and uranium-238 concentrations between Bq/kg. The values were close to the values determined in in lake Riuttalampi by STUK (see Table 2). High Cs-137 concentrations (max. 33 Bq/kg) existed in the upper part of the lake sediment in Riuttalampi. This may be due to the Chernobyl accident in Like Cs-137 also Pb-210 concentrations were much higher in the surface sediment than in the lower parts. Radiometric concentrations were low in moss samples. In moss almost all Ra-226, Ra-228 and U-238 concentrations were below the detection limits. Table 6. Radionuclide concentrations in lake sediments, stream sediments and moss samples in the Riutta area. Sampling was carried out in August Sampling sites are presented in Fig Ra 228 Ra Laboratory Sampling site, code depth Bq/kg Bq/kg Bq/kg Bq/kg Bq/kg Bq/kg Bq/kg Lake sediment LO P cm, Riuttalampi 140 ± ± ± ± ± 2 94 ± 8 33 ± 3 LO P cm, Riuttalampi 150 ± ± ± ± ± 3 54 ± ± 0.9 LO P cm, Riuttalampi 100 ± 40 20± ± ± ± 2 54 ± 8 <0.5 LO P cm, Urkkalampi. 100 ± ± 2 75 ± ± ±2 27 ± _0,9 L P cm, P-Urkkalampi 56 ± ± ± ± ± 2 27 ± 7 16 ± 2 Stream sediment L P9, Kuusoja. 100 ± ± ± ± ± ± ± 2 L P10, Riuttapuro. 55 ± ± ± ± ± ± ±2 L P11, Kuusoja 120 ± ± ± ± ± ± ± 4 L P12, Kuusoja 125 ± ± 5 90 ± ± ± ± ± 3 L P13, Kuusoja 83 ± ± ± 50 < ± ± ± 2 Moss L Riutta Sa P1 <10 <5 < ± ± ± 8 L Riutta Sa P2 <20 <10 < ± ± ± 4 L Riutta Sa P3 <20 <15 < ± ± ± 7 L Riutta Sa P4 <20 <10 < ± ± ± 8 L Riutta Sa P5 <100 <10 < ± ± ± U 210 Pb 228 Th 40 K 137 Cs Regional distribution of uranium-238 concentrations is presented in Fig. 17. In this figure the data from (STUK) and 2006 (GTK) are combined. Uranium in organic sediments is

27 Geologian tutkimuskeskus 25 quite evenly distributed in the area. Some elevated concentrations exist some hundred meters upstream of the Ristimonttu occurrence and in lake Riuttalampi. Fig. 17. Uranium-238 concentrations in stream and lake sediments. Results from the studies in (STUK) and 2006 (GTK) are combined (see Fig. 9 and 11) Results of the chemical analysis Groundwater Dissolved uranium concentrations in groundwater varied in the drill hole samples between µg/l and total concentrations between µg/l (Table 7). The concentrations were clearly higher than elsewhere in the area. Together with uranium also Co, Cu, Mo, Fe and Mn

28 Geologian tutkimuskeskus 26 Table 7. Element concentrations in lake, river and groundwater samples in the Riutta area. Concentrations are based on total analysis (acid soluble elements) and partial analysis (dissolved elements). Sampling sites are presented in Fig. 11. Other elements analysed are presented in Appendix 5. Sampling As Co Cu Mo Ni Zn Fe Mn Th U 2- SO 4 S site µg/l µg/l µg/l µg/l µg/l µg/l mg/l µg/l µg/l µg/l mg/l mg/l Partial analysis (dissolved elements) Groundwater 1 drilled well < < drilled well < < dugwell < < dugwell < < < (9 m) drill hole (24 m) drill hole dugwell Median in Finland 1) < < Median in Finland 2) < Quality requirements 3) Stream water 9 river Kuusoja river Riuttapuro < < river Kuusoja river Kuusoja river Kuusoja river Matarinsuo Median in Finland 4) Lake water 5 lake Riuttalampi lake Urkkalampi lake P-Urkkalampi Total analysis (acid soluble elements) 1 < <0.2 < < < < <0.2 < < <0.03 <0.5 < < < < < (9 m) < < (24 m) < <0.2 < <3 < < < <3 < < < <1 <0.2 <3 < < < <3 < < < <3 < < < <3 < < <0.2 < < ) Median values of Finnish wells drilled into the overburden and 2) wells drilled into the bedrock according to Lahermo et al. (2002). 3) Quality requirements and recommendations for household water in Finland, small units, STMa ) Median values for stream water in Finland according to Lahermo et al. (1996).

29 Geologian tutkimuskeskus 27 concentrations were elevated in the drill hole samples. In the sample collected in the Matarinsuo area (sampling site 14, Table 7) the uranium concentration was high (1.24 µg/l, partial solution). Also SO 4 2- concentration (8.0 µg/l) and copper concentration (1.06) were elevated and exceeded the median values in Finland. It should be mentioned that in the dugwell in the southwestern part of lake Riuttalampi (sampling site 4), the uranium concentrations were quite high (dissolved µg/l and total 1.01µg/l). This may be due to elevated uranium concentrations in bedrock and till, because several uranium-bearing boulders are found close to this dugwell (see Fig. 2 and 11). In Finland the median uranium concentration in dugwell waters is 0.09 µg/l (Lahermo et al. 1996). Lake sediment, stream sediment and moss samples Uranium concentrations (6-17 mg/kg) in lake sediments were 2-5 times higher than the median value in Finland (3 mg/kg, Tenhola 1988, the value of 3 mg/kg is based on ignited samples). Concentrations in the lakes in the Riutta area were over 10 times lower than in lake Ylä- Paukkaja close the Paukkajanvaara mineralization (Tenhola 1978). Highest Pb, U, Ni, Zn, Cd, As and Th concentrations exist in the most upper part of the sediment column. In stream sediments uranium concentrations were 2-4 times higher than the Finnish average values. Highest uranium concentration (8.55 mg/kg) was found in Riuttapuro (Table 8). Heavy metal concentrations (As, Cd, Co, Cu, Mo, Ni, Pb) were higher than Finnish average values. Table 8. Element concentrations in lake- and stream sediments in the Riutta area. Reference values for lake sediments are based on Verta et al. (1990) and Mäkinen & Pajunen (2005) and for stream sediments Lahermo et al. (1996). Sampling sites are presented in Fig. 11. Other elements analysed are presented in Appendix 5. Sampling site, As Cd Co Cr Cu Mo Ni Pb Th U Zn depth mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg Lake sediments P cm, lake Riuttalampi P cm, lake Riuttalampi P cm, lake Riuttalampi P cm, lake Urkkalampi P , lake Pieni Urkkalampi Median in Finland ) 115 Stream sediments P9 river Kuusoja P10 river Riuttapuro P11 river Kuusoja P12 river Kuusoja P13 river Kuusoja Median in Finland ) Tenhola (1988). The concentrations are based on ignited samples.

30 Geologian tutkimuskeskus 28 In moss samples all uranium concentrations are below the detection limit (0.05 mg/kg). In southern Finland, where several small uranium occurrences are known to exist, uranium concentrations in moss are quite high and vary in large areas between mg/kg. This is due to minerogenic dust derived from local soil and bedrock (Salminen et al. 2004). Also, heavy metal concentrations in moss samples were low (Table 9). Most heavy metals are slightly enriched in the samples collected near the Riutta occurrence (sample code Riutta Sa P1). This may be caused by the traffic on the road nearby. The concentrations correspond approximately the background values in the granite areas in Mid-Finland (e.g. nickel concentrations are less than 2 mg/kg, Rühling et al. 1992; see also Loukola-Ruskeeniemi et al. 1998). Table 9. Element concentrations in moss in the Riutta area. Sampling sites are presented in Fig. 11. Other elements analysed are presented in Appendix 5. Sampling site As Cd Co Cr Cu Mo Ni Pb U Zn mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg Riutta Sa P1 < < Riutta Sa P2 < < Riutta Sa P3 < < Riutta Sa P4 < < Riutta Sa P5 < < SUMMARY The COGEMA s claim application for uranium prospecting at Riutta was approved in the Ministry of Trade and Industry in October The decision gives a possibility to carry out ore exploration in certain limits. Before the start of the exploration an environmental present state survey was decided to start. Quaternary mapping and geochemical sampling were carried out in August and September Surface water, groundwater and organic sediment samples were collected throughout the area. The samples were analysed in the Geological Survey of Finland (GTK) and in the Radiation and Nuclear Safety Authority (STUK). Also some results of the earlier geochemical studies in the Riutta area, made by STUK, were presented. The Riutta claim area is situated in eastern Finland about 30 km NE of Joensuu in the municipalities of Eno and Kontiolahti. In the close vicinity of the known mineralizations there is no settlement, but on the shore of lake Riuttalampi, 1-2 km apart from the mineralized area, there are two farming houses (possibly summer residences). In the northwestern part (c. two kilometers from the border of the claim), is an environmental protection area Kolvananuuro, which belongs to the Natura protection programme. Three large groundwater reservoirs for the municipalities of Eno and Kontiolahti are situated 1-5 km southwards from the Riutta mineralization, partly within the claim area. The bedrock at Riutta is composed of Archaean ortho- and paragneisses overlain by Paleoproterozoic quartzitic metasediments. The Riutta uranium mineralization, including pitchblendebearing veins, is hosted by sericite-quartz schist in the contact zone between the Proterozoic schists and the Archaean granitoids and migmatites. Quaternary geology in the area is complicated with a large ice-marginal formation comprising the whole Kuusoja valley. Groundwater

31 Geologian tutkimuskeskus 29 reservoirs are situated in this area. Uranium-bearing boulder fans show a clear transport direction between o. The Riutta study area and the Kuusoja valley belong to the Kuusoja drainage area (102 km 2 ) with a discharge to river Pielisjoki in the south. The amount of precipitation in September 2006 was mm, which was much lower than usually at that time. Due to a very dry summer the discharge of water was only 2.6 l/s when it was in October l/s. Three separate groundwater reservoirs are situated in the Kuusoja valley. The precipitation in the Kuusoja valley produces groundwater approximately 8500 m 3 /day. The pumping station of the Kuvassärkkä is situated in the southernmost reservoir producing groundwater 700 m 3 /day. In October the amount of precipitation was greater than mm, exceeding times normal values. According to the estimates of the North Karelia Regional Environment Centre, runoff in North Karelia at the end of summer 2006 was only 2-6 l/s, due to a very dry summer. The end of October and the beginning of November were rainy causing higher values of water discharge, l/s. Annual precipitation in the area has been in recent years mm, but in a very rainy summer 2004 annual precipitation was even over 850 mm. The ph values in surface and groundwater were normal varying mainly between The lowest ph value (5.98) was found in the water of the groundwater pumping station. In all samples, taken from the groundwater area, redox-values and oxygen amounts were high and electric conductivity values were low. Radiometric determinations in water samples showed, that total alpha (< Bq/l) and radium-226 concentrations (< Bq/l) were very low throughout the whole area. The highest values were found in the drill hole samples. Also, uranium concentrations ( μg/l, total analysis) in the drill hole samples were higher than elsewhere in the area. In stream water sample collected in the Matarinsuo area the uranium concentration was elevated (1.24 µg/l). Heavy metal concentrations were low in the water samples throughout the area. In one sampling point (lake Riuttalampi) manganese concentration was high (1700 µg/l) exceeding ca 30 times the quality requirement values for house- hold water in Finland. As a whole uranium and trace metal concentrations were far below the limits of the requirements for household water in Finland. In the groundwater area (three southernmost sampling sites) total alpha concentrations (<0.02 Bq/l) as well as Ra-226 (< Bq/l) were extremely low. Also, uranium concentrations ( µg/l) and most heavy metal concentrations were low. In lake sediments in Riuttalampi radium-226 concentrations varied between Bq/kg and uranium-238 concentrations between Bq/kg. The values were close to the values determined in in lake Riuttalampi by STUK. A high Cs-137 concentration (max. 33 Bq/kg) existed in the upper part of the lake sediment in Riuttalampi. This may due to the Chernobyl fallout in Like Cs-137, also Pb-210 concentrations were higher in the surface sediment than in the lower parts. In stream sediments all radionuclide concentrations were low. In moss radiometric concentrations as well as heavy metal concentrations were low. Almost all Ra- 226, Ra-228 and U-238 concentrations were below the detection limits. Uranium concentrations in lake sediments (6-17 mg/kg) were 2-5 times higher in the Riutta reservation area than in Finland, in average. However, the concentrations in lake sediments were

32 Geologian tutkimuskeskus 30 over 10 times lower than in lake Ylä-Paukkaja (close to the Paukkajanvaara mineralization). Highest Pb, U, Ni, Zn, Cd, As and Th concentrations existed in the uppermost part of the lake sediment column. Also, in stream sediments uranium concentrations were 2-4 times higher than the median value in Finland. 6 REFERENCES Ahtiainen, M. and Naakka, S Palo- ja Kuokkasenkankaan pohjavesitutkimus Kontiolahden kunnassa. Report 0792D001/512. Pohjois-Karjalan vesi- ja ympäristöpiiri (in Finnish). Björklund, A Paukkajanvaara: uranium in till above mineralization. Journal of Geochemical Exploration Vol 5, No. 3, Huhma, A Riutan tutkimukset Raportti 050/4242/AH/62, Outokumpu Oy Malminetsintä 4 p. (in Finnish). Kesola, R. Enon kartta-alueen kallioperä. Summary: Pre-Quaternary rocks of the Eno map sheet area. Suomen geologinen kartta : kallioperäkarttojen selitykset lehti 4242, 40 p. Kohonen, J. and Marmo, J Proterozoic lithostatigraphy and sedimentation of Sariola and Jatuli-type rocks in the Nunnanlahti-Koli-Kaltimo area, eastern Finland: implications for regional basin evolution models. Geological Survey of Finland, Bulletin 364, 67 p. Kohonen, J. & Vuollo, J Kolin valkeat rannat. In: Lóven, L. & Rainio, H. (eds). Kolin perintö: kaskikasvusta kansallismaisemaan. Helsinki: Espoo: Metsäntutkimuslaitos, Summary: One thousand wells the physical-chemical quality of Finnish well waters in Geological Survey of Finland. Report of Investigation 155, 92 p. Lahermo, P., Väänänen, P., Tarvainen, T., Salminen, R Suomen geokemian atlas. Osa 3: ympäristögeokemia purovedet ja sedimentit. Geochemical Atlas of Finland. Part 3: Environmental geochemistry stream water and sediments. Geological Survey of Finland, Espoo, 147 s. Laiti, I. O Geological Map of Finland, Pre-Quaternary Rocks. 1: Sheet 4242, Eno. Geological Survey of Finland. Loukola-Ruskeeniemi, K., Uutela, A., Tenhola, M., Paukola, T Environmental impact of metalliferous black shales at Talvivaara in Finland, with indication of lake acidification 9000 years ago. Journal of Geochemical Exploration 64 (1998), Mustonen, R., Ikäheimonen, T. K., Salonen, L. ja Sillanpää T Uraanin louhinnan ja rikastuksen radiologiset ympäristövaikutukset Enon Paukkajanvaarassa. STUK-B-VALO 61. Säteilyturvakeskus, 26 p. (in Finnish). Mäkinen J., Pajunen, H Correlation of carbon with acid-soluble elements in Finnish lake sediments: two opposite composition trends. Geochemistry: Exploration, Environment, Analysis, Vol. 5 (2),

33 Geologian tutkimuskeskus 31 Nenonen, K Kenttäraportti malminetsintää palvelevista maaperätutkimuksista Riutan malminetsintätyömaalla Kontiolahdella ja Enossa. Geologian tutkimuskeskus, sisäinen raportti P , 5 p. (in Finnish). Piirainen, T Die Petrogie un die Uranlagerstätten des Koli-Kaltimogebiets im finnischen Nordkarelien. Bull. Comm. Geól. Finlande, n:o 237, 99 p. Rainio, H The Pielisjärvi end moraine: Kuusoja valley train, Eno and Kontiolahti. In: K. Mäkinen (ed.) Mid-Norden Project: Subproject Quaternary Geology. Guide for the excursion to central Finland Geological Survey of Finland, Ruotsalainen, A., Seisminen tutkimus Enon Riutassa Geologian tutkimuskeskus, sisäinen raportti Q19/4242/84/1/23, 2 p. (in Finnish). Räisänen, M-L., Hämäläinen, L., Westerberg, L-M., Selective extraction and determination of metals in organic stream sediments. Analyst 117, Rühling, Å., Brumelis, G., Goltsova, N., Kvietkus, K., Kubin, E., Liiv, S., Magnússon, S., Mäkinen, A., Pilegaard, K., Rasmussen, L., Sander, E. Steinnes, E Atmospheric heavy metal deposition in northern Europe Nord 1992: 12. Nordic Council of Ministers. AKA-PRINT A/S, Århus, 41 pp. Salminen, R., Chekushin, V., Tenhola, M., Bogatyrev, I., Glavatskikh, S. P., Fedotova, E., Gregorauskiene, V., Kashulina, G., Niskavaara, H., Polischuok, A., Rissanen, K., Selenok, L., Tomilina, O., Zhdanova, L Geochemical atlas of the eastern Barents region. Amsterdam: Elsevier, 548 p. Salminen, R. (ed.), Alueellinen geokemiallinen kartoitus Suomessa vuosina (in Finnish). English summary: Regional geochemical mapping in Finland in Geological Survey of Finland, Report of Investigation 130, 47 p (in Finnish). Sillanpää, T., Ikäheimonen, T. K., Salonen L., Taipale, T. ja Mustonen R Paukkajanvaaran vanhan uraanikaivos- ja rikastamoalueen ja sen ympäristön radioaktiivisuustutkimukset. STUK-B-VALO 56. Säteilyturvakeskus, 94 p. (in Finnish). Tenhola, M Järvisedimenttianomalioiden luokittelusta Pohjois-Karjalassa ja Kainuussa. Geologian tutkimuskeskus, sisäinen raportti S/41/0000/1/1978, 8 p. (in Finnish). Tenhola, M Alueellinen geokemiallinen järvisedimenttikartoitus Itä-Suomessa. English summary: Regional geochemical mapping based on lake sediments in eastern Finland. Geological Survey of Finland, Report of Investigation 78, 42 p. Tyynismaa, J Land use Analysis and Environmental Screening, Itä-Uusimaa and Eno reservation areas, report, , 14 p.

34 Geologian tutkimuskeskus 32 Verta, M., Mannio, J., Iivonen, P., Hirvi, J.-P., Järvinen, O., & Piepponen, S Trace metals in Finnish Headwater lakes Effects of Acidification and Airborne Load. In Kauppi, P., Anttila, P. & Kenttämies, K. (eds.). Acidification in Finland. Springer-Verlag Berlin, Heidelberg, Äikäs, O Raportti lohkareprojektin kenttätöistä ja Kontiolahden Riutan uraaninetsintätyömaalla (in Finnish). Äikäs, O Selostus uraanitutkimuksista Enon ja Kontiolahden kunnissa valtausalueella Riutta 1, kaivosrek.nro 3495/1, Geologian tutkimuskeskus, sisäinen raportti M 06/4242/- 89/1/60, 20 p. (in Finnish). Äikäs, O., Seppänen, H., Yli-Kyyny, K., Leino, J Young uranium deposits in peat, Finland : an orientation study. Geological Survey of Finland. Report of Investigation 124, 21 p. 7 APPENDICES APPENDIX 1. Quaternary deposits of the Riutta area APPENDIX 2. Forestry 1: of Riutta area APPENDIX 3. Surface water runoff and drainage basins 1: of the Riutta area APPENDIX 4. Regional lake sediment sampling in Finland in APPENDIX 5. Chemical analysis

35 Geologian tutkimuskeskus 33 APPENDIX 1. Quaternary deposits in the Riutta area

36 Geologian tutkimuskeskus 34 APPENDIX 2. Forestry 1: in the Riutta area

37 Geologian tutkimuskeskus 35 APPENDIX 3. Surface water runoff and drainage basins 1: in the Riutta area

38 Geologian tutkimuskeskus 36 APPENDIX 4. Regional lake sediment sampling in Finland in