2009:066

M A S T E R ' S T H E S I S

Geochemical Baseline Study of GoldMineralization in the Barsele Area,

North Sweden

Elvis Tangwa

Luleå University of Technology

Master Thesis, Continuation Courses Exploration and Environmental Geosciences

Department of Chemical Engineering and GeosciencesDivision of Applied Geology

2009:066 - ISSN: 1653-0187 - ISRN: LTU-PB-EX--09/066--SE

Master Thesis

Geochemical Baseline Study of Gold

Mineralization in the Barsele Area,

North Sweden

Elvis Tangwa

Supervisor: Prof. Björn Öhlander

Luleå University of Technology

Master Thesis, Continuation Courses

Exploration and Environmental Geosciences

Department of chemical Engineering and Geosciences

Division of Applied Geology

ii

Quotation

“I have learned that success is to be measured not so much by the position that one has

reached in life as by the obstacles overcome while trying to succeed.” (Booker T Washington, 1856-1915)

iii

Abstract Two lake sediment cores and 10 lake water samples were sampled at different depths to

assess trace metal content and water quality prior to the possibility of mining two orogenic

gold deposits at Barsele, North Sweden. Existing regional water data sampled at different

seasonal conditions was provided. Data from the Swedish Environmental Protection Agency

(SEPA), the Kalix River and Lake Kutsasjärvi were also used as reference data to quantify

metal pollution and assess their possible impact on aquatic systems. Bedrock composition,

location of ore body and existing assay data were equally reviewed.

Till close to gold deposits has high As but low base metal enrichment. Streams B7and B4

interacting with the ore bodies and mineralized till has a neutral pH and a good buffering

capacity due to the weathering of calcite veins associated with ore bodies. Arsenic (18.2µg/l,

SEPA class 4, Stream B7) is the most elevated in the drainage basin while Zn, Ni, Cu Hg,

Mo, Cd and Pb in all surface waters are within the tolerance limit (SEPA class 1or2).

Sorption onto Fe- oxy hydroxides in addition to a near neutral pH seems to limit greatly the

mobility of heavy metals but less on the mobility of As due to its ability to form mobile

complex anions. Lake water has a relatively low metal content due to its neutral pH and its

near stable oxygen concentration. Arsenic (SEPA class 4) is particularly enriched in lake

sediments, in association with precipitation of Fe-oxyhdroxide. Copper and Ni are equally

elevated in lake sediments. Generally, metal enrichment in lake sediment is higher at

sampling station A compared to station B and reflects variations in redox processes and the

recycling of Fe-Mn. Although lake water and mineralized streams have a good buffering

capacity, their metal content could be upgraded once mining begins because large volumes of

rocks will be exposed to weathering. Thus, adequate measures should be taken to dispose

waste rocks and monitor water chemistry.

Keywords: water chemistry, lake sediments, trace elements, arsenic pollution, gold

mineralization, Barsele

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Table of Contents Quotation ................................................................................................................................................ ii

Abstract .................................................................................................................................................. iii

Table of Contents ................................................................................................................................... iv

1 Introduction .......................................................................................................................................... 1

1.1 Background Information ............................................................................................................... 1

1.2 Location of Study Area ................................................................................................................. 2

1.3 Objectives ..................................................................................................................................... 3

2. Bedrock geology and mineralization .................................................................................................. 4

2.1 Regional Geology ......................................................................................................................... 4

2.2 Geology of Barsele Area ............................................................................................................... 6

2.3 Mineralization ............................................................................................................................... 6

2.4 Quaternary Geology and Mineralization ....................................................................................... 8

3) Materials and Methods ..................................................................................................................... 12

3.1 Regional water ............................................................................................................................ 12

3.2 Lake water and Lake Sediments ................................................................................................. 12

3.3 SEPA Data .................................................................................................................................. 15

4. Results and Discussions .................................................................................................................... 16

4.1: Bedrock Assay ........................................................................................................................... 16

4.2: Till/Soil ...................................................................................................................................... 19

4.3 Regional Water ........................................................................................................................... 23

4.4 Lake water ................................................................................................................................... 32

4.5 Lake Sediments ........................................................................................................................... 35

5. Conclusions and Recommendations ................................................................................................. 41

Acknowledgments ................................................................................................................................. 42

References ............................................................................................................................................ 43

Appendices ............................................................................................................................................ 46

Appendix 1: lake water station A ...................................................................................................... 46

Appendix 2: lake water station B ...................................................................................................... 46

Appendix 3: lake sediments Station A .............................................................................................. 47

Appendix 4: lake sediments station B ............................................................................................... 48

1

1 Introduction

1.1 Background Information

Geochemical Baselines, refers to the natural variation in the concentration of an element in

the superficial environment (Salminen and Gregorauskiene, 2000 and Salminen and

Tarvainen, 1997). Geochemical baseline studies provide information which might be

indicative of an ore occurrence (e.g. Hawkes and Webb 1962) or it may provide guidelines

for environmental legislation; because it prescribes limits for heavy metals in contaminated

land and other surficial materials as defined by environmental authorities, (Salminen and

Tarvainen, 1997). Baseline concentrations depends on sample material collected, grain size,

analytical and extraction methods (Rose et al., 1979). For this reason, common challenges

with baseline studies include the fact that sometimes different scales or averages or

boundaries are used. Moreover, detail information regarding how regulatory levels have been

established may be lacking. Hence, baseline concentration may vary for different countries

and even within a particular project area, (Reimann and Garett, 2005). In this study,

guidelines provide by the Swedish Environmental Protection agency (SEPA) and also data

from the Kalix River and Lake Kutsasjärvi which are both unpolluted and unmineralized

surface waters in north Sweden have been used to assess metal pollution in surface waters

and lake sediments in the Barsele area. The SEPA guidelines prescribes different ranges of

concentration for different elements in different sampling media taking into account the

adaptability level of biological systems under different metal concentrations and

environmental conditions. As a means to quantify metal pollution, SEPA has grouped these

ranges of element concentrations into five different classes, (Table2 and 3).

Gold mineralization in the Barsele area is one of the more than 85 pyritic Zn-Cu-Au-Ag

massive sulphide deposits that make up the well known mineralized Skellefte district in north

Sweden (Weihed et al., 1992). In such a region where sulphides have concentrated several

orders of magnitude than their average crustal concentrations, Acid Rock Drainage (ARD) is

a common environmental problem likely to be experienced before, during and after mining.

Hence, background metal concentrations in sediments or till, surface water and subsequently

groundwater will vary and may greatly deviate from those in unmineralized areas (Rose et al.,

1979). More to these problems is erosion, loss of biodiversity and the leaching of processed

water onto surface and ground water during mineral exploitation. For these reasons,

accountability and environmental performance are important issues for mining companies

today. To meet these challenges and mitigate their effects on the environment, it is important

to understand the inherent hydrogeochemical conditions as well as the geochemistry of lake

sediments in the study area.

In keeping with environmental standards and to prepare the company for any future

exploration and mining operations, preliminary hydrogeochemical study was carried out in

the Barsele area by Pelagia Environmental AB, an environmental consulting firm on behalf of

Northland Resources AB. As a follow up to this study, the geochemistry of lake water and

lake sediments in addition to existing regional water data provided by Pelagia Environmental

AB were further studied. In this study, metal content in bedrock, till, surface water and lake

sediments have also been studied and compared to their average crustal concentrations and

their concentrations likely to be observed in an unmineralized river such as the Kalix River

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(Pekka et al., 2008) and also in an unmineralized lake such as Lake Kutsasjärvi,

(Peinerud, 2000).

However, besides bedrock composition, the geochemistry of surface water is also controlled

by factors such as pH, relief, climate, oxidation-reduction, adsorption and the mixing of

waters (Levinson, 1974). On the other hand, the geochemistry of lake sediments is influenced

by particle size, redox processes, sedimentation rate, groundwater composition, chemical

speciation, and the recycling of Mn-Fe in pore water, (Stumm, 1885).

Gold exploration in the Barsele area was initiated by Terra Mining INC (1984-1998)

followed by MimMet PLC (2003) and then Northland Resources INC (2004). Presently,

Northland Resources AB, a subsidiary of Northland Resources INC, a Canadian Exploration

/mining company is actively involved in Fe, Cu and Au exploration in Finland and North

Sweden (Barsele technical report 2006).

1.2 Location of Study Area

Regionally, Barsele is located about 230km from Umeå and about 519km from Kiruna.

Barsele has an undulating relief which is characterized by wide plains and isolated hills

occurring at slightly different altitude. Hills are dominant in some location and could reach

an altitude of 791m, while plains lay at an altitude of about 260 – 400m, Geological Survey

of Sweden (SGU). Barsele and its environs are surrounded by numerous lakes, rivers and

streams and a thick coniferous forest. Annual precipitation ranges between 800 to 1,000

millimetres. Winter conditions prevail from late November to early/mid April with snow

cover normally in the range of 50 to 75 centimetres.

The project area is located some 40 kilometres east-southeast of the town of Storuman in

Västerbottens Län, a regional district of northern Sweden. The geographical coordinates of

the project area are approximately 650.05` north latitude and 17

0. 30` east longitude,

(Figure 1)

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Figure 1 Location map of Barsele and its Environs

1.3 Objectives

The main objectives of this study are to:

a) Evaluate the hydrogeochemical conditions of Barsele and its environs and provide

baseline information against which any potential impact of future mining operations

on water quality and metal content in lake sediments can be assessed.

b) Interpret existing regional water data and to supplement existing results provided by

Pelagia Environmental AB.

c) Correlate and account for variations between metal content with depth in lake water

and lake sediments.

d) Understand the influence of climate, geology, proximity of ore body on the

geochemistry surface water and lake sediments.

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2. Bedrock geology and mineralization

2.1 Regional Geology

The project area occurs within the Skellefte district which covers an area of 120km by 30km

and is located on the Paleoproterozoic part of the Fennoscandian Shield. The Fennoscandian

Shield is dominantly made up of Achaean, Proterozoic gneisses and greenstone rocks which

have undergone several episodes of deformation throughout history with a peak in most areas

during the Svecokarelian orogeny c 1.90 and 1.80 Ga, (Lundqvist et al., 1998b; Bergman et

al., 2001). Sedimentary and felsic magmatic rocks of low to medium metamorphic grade,

elongated in a NW-SE direction are the dominant rocks in the Skellefte district, (Weihed et

al., 1992). These metasedimentary and metavolcanic rocks in a regional context constitute the

Svecofennian rocks system. In the study area, these rocks are without any known Achaean

basement, (Mellqvist et al., 1999 and Richard 1986). Generally, granites especially the

Revsund granite are the most abundant covering about 70% of the Skellefte district (Richard

1986, Fig 2.1.) They are generally course-grained, porphyrytic and light gray in colour.

Within the granite areas, there are several rather large granodiorite intrusive which have been

greatly deformed. Granites and supracrustal rocks are often cut by dolerite dykes especially in

the in the project area (Weihed, 1992b, Fig 2). Felsic volcanic rocks in this region have been

interpreted as pyroclastic rocks formed due to a violent explosive submarine volcanism at

large volcano which resulted to the scattering of these rocks in the district. (Lundberg, 1980;

Richard, 1986; Vivallo and Classon, 1987).

The west end of the Skellefte district is bordered by Caledonian rocks which are mainly

Neoproterozoic to Silurian metasedimentary and metavolcanic rocks. These rocks lie

structurally on top of the autochthonous, plat formal cover sequence to the Precambrian

crystalline basement rocks, (Stephens et al. 1997)

The south east of the Skellefte district is dominated by metasedimentary rocks which occur

within a sedimentary basin, the Bothnia basin. These metasedimentary rocks contain

remnants of older volcanic rocks c. 1.95Ga which are confined to the Knaften and Barsele

areas. Still within the south east of this district, intrusive granites and some pegmatites are

associated with high grade gneissic and migmatitic equivalence of supracrustal rocks. These

intrusives are commonly referred to as the as Skellefte granites and date about 1.80Ga

(Weihed et al., 2002; Romer and Smeds, 1994). Similar granites to the south are referred to as

Härnö granites (Classon and Lundqvist, 1995).

The northern part of the Skellefte district consist of extensively less deformed and less altered

supracrustal rocks. They are mainly of brown continental felsic intrusion, porphyrytic lavas,

sub volcanic intrusions and tuffs and minor sediments called Arvidsjaur Group. The

Arvidsjaur Group is topmost layer of the regional stratigaphy of the Skellefte district. Under

laying this layer is the Vargsfor which together with the Arvidsjaur group are with or with

any major unconformity (Skiöld et al.; 1993 & Billström and Weihed 1996). They are red in

colour, often oxidized, have high potassium content and occur in association with welded

ignimbrites and accretionary lapilli and strongly resemble rocks of lower horizon, the

Skellefte Group, (Barnstorm 2001). The Vargfors Group is composed of fine to coarse-

grained sedimentary rocks such as conglomerates with some intercalations of volcanic rocks.

Under laying the Vargfors group is the Skellefte group. They are notably; acid porphyry

characterized by volcaniclastic rocks, mainly rhyolite and rhyodacites, coherent sub volcanic

porphyrytic intrusion lavas and intercalated sedimentary rocks such as mudstones, breccias

and conglomerates, (Allen et al., 1996b). Some coarser sedimentary rocks occur within the

5

Skellefte Group and are lime-cemented, but only very rarely does limestone occur within the

Skellefte Group. They were emplaced between 1880-1890Ma and have a complex internal

stratigaphy, (Billstöm and Weihed.; 1996). Lundberg (1980) interpreted the depositional

environment of many of these volcanic rocks as shallow water or sub aerial. More about the

regional stratigaphy of the Skellefte district has been extensively studied by (Allen et al.,

1996b)

Figure 2: Bedrock Maps of Barsele and its Environs showing, the main lithological units. Map produced

by the Geological Survey of Sweden (SGU 2003)

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Tectonically, the Skellefte District is considered to be a remnant of a ca. 1.9 Ga

Palaeoproterozoic volcanic arc formed at the margin of an Achaean continental landmass

(Allan et al, 1996). The Svecofennian rocks in this district are known to have been formed

after the final break-up of the Karelian Craton at c.a 1.95 Ga and Svecokarelian Orogeny.

During these processes, a sedimentary basin, the Bothnian basin was formed towards south.

Within this basin, quartzite, conglomerates, turbidites and graphite schist were deposited and

later metamorphosed in the lower to upper amphibolites facie .These rocks were later

intruded by different types of granitites during the c 1.9-1.8 Ga Svecokarelian Orogeny

(Claesson &Lundqvist 1995).

2.2 Geology of Barsele Area

The project area lies within a boundary-zone between the Bothnian metasedimentary basin to

the south and a volcanic province to the north (Barsele project technical report, 2006).

Metasedimentary and metavolcanic rocks are the most common, with the metasedimentary

rock being the most abundant, (Figure 2). The metasedimentary assemblages include:

metamorphosed greywacke which are the most abundant, pelites and to a lesser extend

conglomerates equally exist. The metavolcanic rocks consist of felsic, intermediate, mafic,

pillow lava and pyroclastic materials (Richard 1986). The metagraywackes are rich in

graphite and equally contain sulphides minerals. Both rocks are very similar in all aspects

with no clear cut distinction due to alteration and deformation. They are blackish gray,

biotite-rich, and less coherent in appearance. They also contain a higher density of mainly

quartz and feldspar porphyroclasts and thin calcite veins. However, the metavolcanic rocks

are dark grey in colour, contain amphibole as the main mafic mineral and are more uniformly

carbonate-altered (Bark et al.; 2007). The metavolcanic rocks are more specifically referred

to as the Härnö Formation and were probably deposited in a back-arc setting. The felsic

volcanics are thought to represent a volcanic inlier within the Bothnian Basin, or

alternatively, an outlier of the Skellefte district (Classon and Lundqvist, 1995).

These rocks are strongly foliated with a roughly N–S trending and have steeply dipping

foliation planes. They show variable amounts of mainly quartz and feldspar porphyroclasts

and phenocrysts in a more fine-grained matrix. Most supracrustal rocks at Bersele like in

most parts of Sweden and Finland have been intruded by granitoids, mainly tonalite or diorite

dykes, (Weihed, 1992b, Figure 2).

2.3 Mineralization

Mineralization in most parts of north Sweden is associated with Paleoproterozoic rocks. The

Skellefte District hosts over 85 pyritic Zn-Cu-Au-Ag Volcanogenic Massive Sulphide (VMS)

deposits, (Allen et al., 1996 and Wiehed et al., 1992). The District also hosts a few porphyry-

type low-grade Cu deposits and a good number of orogenic gold deposits in different

geological settings, including shear zones (Weihed et al. 1992).

The Barsele area hosts both orogenic and epithermal gold rich VMS deposit. Orogenic gold is

confined to the Barsele central, the Avan, and the Skiråsen zones while epithermal gold is

confined to the Norra zone respectively, (Barsele technical report, 2006, figure 3)

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Figure 3 Map showing location of main ore bodies in project area

Orogenic gold mineralization at Barsele is one in a series of 14 well known gold deposits

related to the NW–SE trending belt of Au in till often referred to as the ―gold line‖, (Figure

4). Epithermal gold on the other hand is mostly associated with faults and fractures. Gold

occurrence is predominantly within a granodiorite that ranges in width from 200 to 500

metres with a strike-extent in excess of some 8 kilometres (Barsele Technical report 2006).

Like in most parts the Skellefte district gold in the Barsele area occurs as native metal locally

alloyed with silver, and demonstrates a general association with arsenopyrite also occurring

with pyrrhotite, calcite, chlorite and biotite. Base metal content of the deposit is typically low

(Barsele Technical Report 2006)

Norra

Avan

Barsele central

Skiråsen

8

Figure 4 Gold content in the till overburden, Västerbotten County. Data from the Geological Survey of

Sweden

2.4 Quaternary Geology and Mineralization

Till and discontinuous soil covers are the dominant quaternary deposits at Barsele and its

environs. The thickest till cover occur at the bottom of wide valleys and extensive plains

(Rudberg 1954). These valleys and plains are characterized by ablation and glaciofluivial till

which are generally coarse-grained, less compacted and well sorted (Ivarsson, 1992). There

equally exist local occurrences of peat deposits in some plains (SGU, 2003)

On hill summits, till is generally shallow or absent and forms discontinuous covers on

bedrock (Figure 5a). The thickness of till cover on hills hardly excess 2m and their

morphology closely follow the topography of the underlying bedrock (Ivarsson, 1992).

However, coarser and thicker till covers of up to about 5-20m usually occur on lee side

positions of hills while basal till (fine till) which is more compacted and has a comparatively

high content of fine fraction occurs on the hill side (Ivarsson, 1992). Glaciofluivial sand and

glaciofluivial gravel equally occur with glaciofluivial grave being the most common.

Till in areas greatly affected by wave ablation is generally coarse-grained and sometimes

have boulder-sized fractions oriented in the direction of ice movement (SGU, 2003). Such

deposits compared to fine till are generally enriched in SiO2 and impoverished in the fine

9

fractions and base metals (Haldorsen, 1982). Generally, fine silt and clay deposit are rare. A

total of 35 samples collected by SGU from an average depth of 2 to 3m show that

homogenous sandy to silty till usually about 0.5m thick overlies a rather heterogeneous

deposit. In most parts of Barsele the boundary between both deposits can be sharp or gradual.

According to Granlund (1943), areas dominated by the Revsund granites are particularly

characterized by sandy to silty till compared to finer till in areas dominated by supracrustal

rocks. He equally observes that granite dominated areas have <25% fine fraction (silt + clay)

with less than 12% heavy minerals while areas dominated by metasedimentary and gneissic

rocks have about 45% and 30% silt +clay respectively. Till samples collect by Northland

Resources AB at depths ranging from 0 to 21m show great variation in physical and chemical

composition. Generally clayey silt is the dominant fine fraction and could be rusty (sulphide

enrichment), black brown, and could contain argillite or granodiorite clast. Elsewhere, clays

are mostly dark gray to light gray and could also be orange, yellow, yellow green, silty or

sandy, and tan with argillite clast. Silt could be sandy, clayey and could contain graphite in

few locations. Till mostly contains angular to subanglar pebbles or fragments of granodiorite,

granite, quartz schist, black shale and rarely fragments of conglomerates, graywackes,

amphibolites, metavolcanics and massive sulphides. Very high As and Cu in till occurs

between 0 to 2.4m and sometimes to about 4.2m below the surface. Elevated concentrations

of As and base metals are associated with dark gray clays, black shale, clayey silt, yellow

orange clay, greenish gray clay, clay with mica, chlorite, schist, amphibole and pyrite in

greywacke but rarely with light clays, except Pb which shows high metal content in some

cases, (Figure 7a and 7b) . Till with angular to sub rounded fragments of schist, and till with

traces of sulphides in granodiorite also have high metal content. A study form a total of 293

samples by (Ivarsson et al., 1992) shows that soil and till pH varies from 4 at the coast of

västerbotten to 5.2 inland and around the study area. The study equally shows that Granite

dominated areas have a relatively low pH compared to area dominated by metasedimentary,

mafic and granodiorite rocks.

The direction of ice movement based on 250 points shows that most bed rocks have two

main directions of ice movement; the older is about 2800 from the west and the younger

which is 3100 -225

0 from the NW is considered to be the dominant direction of flow (SGU,

2003, Figure 5b). Ice flow in most cases is more or less parallel with large river valleys,

boulders and drumlins. (Bergström, 1968).

10

Figure 5a: Till/soil map of Barsel. Project area enclosed in rectangle. Map from the Geological Survey of

Sweden (SGU, 2003)

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Figure 5b: Direction of ice movement; from oldest to youngest. Map from (SGU)

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3) Materials and Methods

3.1 Regional water

A total of 160 regional water samples were collected by Pelagia Environmental AB from 10

sampling stations in 8 water bodies (1 lake, 6 streams and 1 river, Table 3.1). Samples were

collected at different seasonal conditions from October 2001 to September 2002 and again

from May 2005 to November 2008 to check for variations in chemical composition. Each

stream was given a reference number for convenience. Samples from all sampling stations

were taken from a depth of 0.2m except for station B3b, where water samples were collected

from a depth of 1m. Samples were filtered in situ using a 0.45µm pore size membrane filter

and analysed for Ca, Mg and Fe using ICP-AES and As, Cu, Pb, Zn, Ba, Cd, Ni, Co, Hg and

other heavy metal using ICP-AM methods (Pelagia Environmental AB, 2008)

The analytical ICP regional water data provided for this thesis was analysed and interpreted

separately and based on the name of each stream

Table 1 (a) Streams sampled by Pelagia (red dots figure 5) and their respective coordinates. Data

compiled by Pelagia Environmental AB

River Local Reference Number of Samples Coordinates

Vintervägabäck B1 20 7214535/1582810

Skirträskbäcken B2 20 7214701/1582872

Skirträsket B3y 18 7217070/1580900

B3b 14 7217070/1580900

Stentjärnbäcken B4 20 7217820/1579739

Främmentjärnbäcken B5 20 7217916/1579779

Umeälven upp B6 13 7215880/1574550

Barseleavanbäcken B7 11 7216422/1579258

Umeälven ned B8 13 7207672/1583727

Godängesbäcken B15 11 7217800/1576440

3.2 Lake water and Lake Sediments

In April 2009, sampling was done at two sampling stations in Lake Skirträsket: station A and

station B, (Table 3.1). Both sampling stations are located about 250m and 180m respectively

from the banks of the lake, figure 5. Prior to sampling, water depth at station A (17.8m) and

station B (19.6m) was investigated using an echo sounder. The geographical coordinates of

sampling stations were noted with the aid of a global positioning system (GPS), (Table 1b).

Table 1(b) Lake sampled and their corresponding sampling stations (blue dots fig 3.1), depth, number of

samples collected and coordinates

Lake Sampling stations

Depth Number of water samples

Number of sediment samples

Coordinates

Skirträsket A 17.8 5 5 7216960/1580721

B 19.5 5 5 7215928/1581341

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Water pH, conductivity and temperature, were equally investigated in situ using a Hydrolab

minisonde (water quality miniprobe). At station A, five lake water samples from different

depths were collected. Simultaneously, 5 lake sediments samples were collected from the

same sampling station using a sediment corer. The same procedure was repeated at sampling

station B. The equipment for water sampling consisted of 12V battery (power source)

connected to a pump onto which pipe was connected a tube to allow the follow of water.

Water samples were collected at intervals of one minute during which pumping voltage was

increased from 2V to 7V to allow water retained in the tube from the preceding depths to be

flushed out. Prior to water sampling, sample containers (plastic bottles) were rinsed three

times with water to avoid contamination. Samples from each depth were filtered using a

0.22µm filter to separate the dissolve fraction from the particulate fraction. Samples were

then collected in plastics bottles and labelled on paper tapes based on their respective depths

and sampling stations. After sampling, water samples were stored for two days at a

temperature of 40C and analysed for Al, Ca, Fe, K, Mg, Na, S and Si using the ICP-AES

methods. Arsenic, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, P, Pb, Sr, and Zn were analysed

using ICP-SMS methods at ALS Scandinavia, an accredited analytical laboratory in north

Sweden, (appendix 1 and 2). Lakes sediments cores about 30cm thick from each sampling

station were collected by slowly deploying to the bottom of a Lake Skirträsket, a sediment

corer on to which a meter tape was attached to check the depth and speed of deployment.

Once collected, sediment cores were sliced at intervals of 1cm. They were then collected in

plastic containers and labelled based on their respective sampling stations. Just like water

samples, they were stored at a temperature 40C for two days and then analysed for SiO2,

Al2O3, CaO, Fe2O3, MgO, MnO, Na2O, P2O5, TiO2, LOI, As, Ba, Cd, Co, Cr, Cu, Hg, Mn,

Mo, Ni, P, Pb, Sr, and Zn by ICP methods at ALS Scandinavia, (appendix 3 and 4).

14

Figure 5: Map showing sampling station, streams and rivers in the project

Blue dots: sampling stations for lake water and sediment. Red dots: sampling station for surface waters

Bedrock assay and till assay data for samples collected at depths in the range of 0 to21m was

provided by Northland Resources AB, and was further studied. The average concentrations of

a few metals in rivers around the project area were compared to the average concentration in

a typically unpolluted or unmineralized river like the Kalix River in northern Sweden (Table

4). To assess metal enrichment in lake sediments, analytical data of As, Cu, Ni, Pb and Zn

were compared to date from Lake Kutsasjärvi, (Table 7).

Umeälven upp, B6

Godängesbäcken, B15 Främmentjärnabäcken, B5

Stentjärnbäcken B4

Barseleavanbäcken, B7

Skirträsket, B3y, B3b

Station A, SSA

Station B, SSB

Skiräskbäcken, B2

Vintervägabäcken, B1

Umeälven ned, B8

15

3.3 SEPA Data

To assess the magnitude of metal pollution on surface water and its possible effects on

aquatic and biological systems, analytical data was compared with data from the Swedish

Environment Protection Agency (SEPA, Table 2). To quantify metal pollution in lake

sediment, metal concentration in lake sediments were also compared with data from SEPA.

Table 2: Classification of water quality status (SEPA, 4913)

Metal concentration in water (µg/l)

Class Description As Cd Cu Ni Pb Zn

1 No or low risk of biological effects

<0.4 <0.01 <0.5 <0.70 <0.2 <5

2 Low risk of biological effect

0.4-5 0.01-0.1 0.5-3 0.7-15 0.2-1 5-20

3 Biological effects can occur

5-15 0.1-0.3 3-9 15-45 1-3 20-60

4 Increasing risk for biological effects esp. in soft nutrient poor, humus poor acidic water

15-75 0.3-1.5 9-45 45-225 3-15 60-300

5 Survival of aquatic organism is affected even after short exposure

>75 >1.5 >45 >225 >15 >300

Table 3. Classification of metal content in sediment based on (SEPA) standards

Class Description Cu (mg/kgTS)

Zn (mg/kgTS)

Pb (mg/kgTS)

Ni (mg/kgTS)

As (mg/kgTS)

Hg (mg/kg TS)

Cd (mg/kg TS)

1 Very low concentration

<15

<150 <50 <5 <5 <0.15 <0.8

2 Low concentration

15-25 150-300

50-150 5-15 5-10 0.15-0.3 0.8-2

3 Moderately high concentration

25-100 300-1000 150-400 15-50 10-30 0.3-1.0 2-7

4 High concentration

100-500

1000-5000 400-2000 50-250 30-150 1-5 7-35

5 Very high concentration

>500

>5000 >2000 >250 >150 >5 >35

16

4. Results and Discussions

4.1: Bedrock Assay

Gold enrichment in bedrock varies from 0.4ppm to 67,000ppb compared to 0.004ppb as its

average crustal concentration (Levinson 1974, table 4.2) and reflects its high enrichment in

the ore body, (figure 6a). The concentration of As varies from 0 to 99999 ppm compared to

1.8ppm as its average crustal concentration. Roughly more than 95% of As concentration is

above the average crustal concentration (figure 6b). This trend also reflects its high content

and close association with Au. The concentration of Copper varies from 0 to 105430ppm. It

can be said that more than 75% of Cu in ore body is below crustal concentration (figure 6c).

Zinc varies from 0 to 99999ppm with about 49% of its content in ore body below average

crustal concentration (figure 6d). The concentration of Pb varies from 0 to 23259 with about

46% of its concentration below the average crustal value (figure 6e). About 89% of Ni is

below crustal concentration. These trends supports earlier studies showing that the gold

mineralization in the ore body is strongly associated with arsenopyrite and also the fact that

base metal enrichment in the ore body is low compared Au (Barsele technical report 2006,

Bark 2007).

Figure 6a: Variation of As concentration in bedrock assay

0

1000

2000

3000

4000

5000

6000

0

5

10

15

20

25

0-1

.8

89

-13

2

26

5-3

08

39

7-4

40

52

9-5

72

74

9-7

92

88

1-9

24

10

13

-10

56

11

45

-11

88

13

21

-13

64

14

53

-14

96

15

89

-16

28

17

17

-17

60

18

49

-18

92

19

81

-20

24

24

65

-25

08

26

85

-27

28

29

49

-29

92

37

41

-37

84

40

49

-40

92

42

69

-43

12

46

21

-46

64

48

85

-49

28

50

17

-50

60

54

57

-55

00

57

63

-58

08

59

85

-60

28

62

51

-62

92

72

61

-73

04

11

00

1-1

10

44

99

96

9-1

00

01

2

Fre

qu

en

cy

% f

req

ue

ncy

Range (ppm)

As in bedrock assay

17

Figure 6b: Variation of Au concentration in bedrock assay

Figure 6c: Variation of Cu concentration in bedrock Assay.

0

2000

4000

6000

8000

10000

12000

14000

16000

0

10

20

30

40

50

600

-45

13

6-1

80

27

1-3

15

40

6-4

50

54

1-

58

5

67

6-7

20

81

1-8

55

94

6-9

90

10

81

-11

25

12

16

-12

60

13

51

-13

95

14

86

-15

35

16

26

-16

70

17

61

-18

05

18

96

-19

40

20

31

-20

75

21

66

-22

10

23

01

-23

45

24

36

-24

85

29

81

-30

25

31

16

-31

60

40

16

-41

60

50

51

-50

95

60

41

-60

85

79

76

-80

20

90

11

-90

55

10

04

6-1

00

90

14

99

6-1

50

40

30

20

6-3

02

50

66

97

0-6

70

15

Fre

qu

en

cy

Fre

qu

en

cy %

Range(ppb)

Au in bedrock assay

0

10

20

30

40

50

60

70

80

90

0

5000

10000

15000

20000

25000

0-4

4

13

3-1

76

26

5-3

08

39

7-4

40

52

9-5

72

66

1-7

04

79

3-8

36

92

5-9

68

10

57

-11

00

11

89

-12

32

13

21

-13

64

14

53

-14

96

15

89

-16

28

17

17

-17

60

19

37

-19

80

20

69

-12

12

22

01

-22

44

23

33

-23

76

24

65

-25

08

25

97

-26

40

28

61

-29

04

29

93

-30

36

46

21

-46

64

59

41

-59

84

99

89-

10

03

2

18

08

5-1

81

28

10

54

25

-10

54

68

fre

qu

en

cy %

fre

qu

en

cy

Range (ppm)

Cu in bedrock assay

18

Figure 6d: Variation of Zn concentration in bedrock assay.

Figure 6e: Variation of Pb concentration in bedrock Assay.

0

5

10

15

20

25

30

35

40

45

0

2000

4000

6000

8000

10000

12000

140000

-45

13

6-1

80

27

1-3

15

40

6-4

50

54

1-

58

5

67

6-7

20

81

1-8

55

94

6-9

90

10

81

-11

25

12

16

-12

60

13

51

-13

95

14

86

-15

35

16

26

-16

70

17

61

-18

05

18

96

-19

40

20

31

-20

75

21

66

-22

10

23

01

-23

45

24

36

-24

85

29

81

-30

25

31

16

-31

60

40

16

-41

60

50

51

-50

95

60

41

-60

85

79

76

-80

20

90

11

-90

55

10

04

6-1

00

90

14

99

6-1

50

40

30

20

6-3

02

50

66

11

6-6

61

60

Fre

qu

en

cy %

Fre

qu

en

cy

Range (ppm)

Zn in bedrock assay

0

10

20

30

40

50

60

70

80

90

0

5000

10000

15000

20000

25000

0-4

48

9-1

32

17

7-2

20

26

5-3

08

35

3-3

96

44

1-4

84

52

9-5

72

61

7-6

60

70

5-7

48

79

3-8

36

88

1-9

24

96

9-1

01

21

05

7-1

10

01

14

5-1

18

81

23

3-1

27

61

32

1-1

36

41

40

1-1

45

21

49

7-1

54

01

58

9-1

62

81

67

3-1

71

61

76

1-1

80

41

84

9-1

89

21

93

7-1

98

02

15

7-2

20

02

28

9-2

33

22

37

7-2

42

02

55

3-2

59

62

64

1-2

68

42

72

9-2

77

22

81

7-2

86

02

94

9-2

99

23

12

5-3

16

84

97

3-5

01

67

04

1-7

08

48

97

8-9

02

19

99

0-1

00

33

11

00

1-1

10

44

15

40

1-1

54

44

19

71

3-1

97

56

Fre

qu

en

cy %

Fre

qu

en

cy

Range (ppm)

Histogram plot for Pb in bedrock assay

19

Figure 6f: Variation of Ni concentration in bedrock Assay

4.2: Till/Soil Table 4. Median metal content in till and bedrock assay compared to their crustal abundance. Au in ppb,

S in % while Ag, As, Cu, Fe, Mn, Mo, Ni, Pb and Zn in ppm (levinson, 1974)

Element Bedrock Till

Average crustal concentration (levinson, 1974)

Ag (ppb) 0.3 0.225 0.007

As (ppm) 180 35 1.8

Au (ppb) 51 7 0.004

Cu (ppb) 25 38 55

Fe (ppb) 9.2 3.25

Mn (ppb) 463 401.5 950

Mo (ppb) 2.5 3 1.5

Ni (ppb) 23 42 75

Pb (ppb) 19 16 12.5

S (%) 0.3 0.23

Zn (ppb) 91 100 70

Arsenic, Au and base metals are equally elevated in till, though to a lesser extent. Generally

till around ore body has very high concentration of As and heavy metals, (figure 8a, 8b, 8c

and 8d). It can be said that dispersed clastic sulphide mineralization in biotite, chlorite,

amphiboles, granodiorite and pyrite which are associated with clayey silt, black clays, and

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

0

5000

10000

15000

20000

25000

Fre

qu

en

cy %

Fre

qu

en

cy

Range (ppm)

Ni in bedrook assay

20

gray clays are probably the main sources of these elements, (fig 2.1 fig 7a, fig 7b,). Till

with such composition are mostly associated with the weathering of mafic metavolcanic.

Elevated metal concentrations could also be due the occurrence of shallow soils in which

metals released from bed rock have been deposited in situ. High As and base metal

concentration in some locations could be due to local occurrence of transported soils or the

occurrence of possible ore bodies. The concentration of Cu, Mo, Ni, and Zn are higher in till

compared to bed rock and could mainly be due elevated concentrations in shallow soils. It

could as well be that their release rates are lower than their input from bedrock, (Land, 1998).

Arsenic, Au, Ag, Fe, S and Mn generally have a higher concentration in bed rock compared

to till.

Figure 7a: fine fraction type in till

Figure 7b Metal content in till fine fraction

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

30.00%

35.00%

40.00%

clay silt Lt gray clay Dark clay+shale fine sand+sand silt

Silt+clay Others

Freq

%

Fine fraction

Frequency % of fine fraction type in till

0

100

200

300

400

500

600

700

800

900

1000

clay silt Lt gray clay Dark clay+shale fine sand+sand silt Silt+clay Others

Ave

rage

met

al c

on

c. (

pp

m)

Fine fraction

Trace metal conc. in fine fraction type in till

Zn Pb Ni Mn Cu As

21

Figure 8a. Thematic map of Arsenic in till

Figure 8b Thematic Map of Copper in Till

22

Figure 8c Thematic Map of Zn in Till

Figure 8d Thematic Map of Pb in Till

23

4.3 Regional Water Table 5: Average metal concentration, pH and other measured parameters in some streams and rivers at

Barsele compared to those in the Kalix River, North Sweden

Measured parameter

Average Concentration in Rivers and Streams Around Project Area

Average Concentration in unpolluted Freshwater (e.g. Kalix River, North Sweden)

B1 B2 B3y B3b B4 B5 B6 B7 B8 B15

As(µg/l) 0.5 ±1.1E-04

2 ±2.8E-04

2 ±2.5E-04

1.8 ±8.1E-04

4.8 ±0.001

1 ±1.9E-04

0.18 ±7.9E-05

18.2 ±5.8E-03

0.16 ±7.78E-05

0.57 ±8.0E-05

0.14

Ca(mg/l) 7.68 ±1.6

9.6 ±071

9.6 ±0.94

9.5 ±0.69

9.97 ±1.16

8.94 ±1.8

3.96 ±1.2

24.9 ±4.32

4.07 ±0.85

4.17 ±0.96

Cd (µg/l) - - 0.077 - 0.0043 - - 0.0022 - 0.0016

Cr (µg/l) 0.19 ±7.3E-05

0.008 ±2.1E-05

0.01 ±1.4-04

0.009 ±4.0-E04

0.016 ±9.0E-05

0.027 ±1.5E-04

0.012 ±6.9E-05

0.016 ±1.0E-04

0.015 ±1.6E-04

0.023 ±7.9E-05

Cu(µg/l) 1.25 ±1.1E-03

0.78 ±5.4E-04

1.6 ±6.6E-04

1.2 ±2.3E-03

0.97 ±6.7E-04

0.93 ±6.0E-04

1.1 ±8.1E-05

1.2 ±8.8E-04

1.12 ±0.0017

1.08 ±8.7E-04

0.5

Fe(µg/l) 96.6 ±0.37

3

4

0.065

34 ±8.4E-04

137 ±0.06

128 ±0.046

88 ±0.256

77.5 ±0.042

112 ±0.053

492

Mg(mg/l) 0.89 ±0.19

0.77 ±0.18

0.74 ±8.3E-02

0.74 ±0.05

0.65 ±7.9E-02

0.857 ±0.21

1.26 ±2.1

1.5 ±0.301

1.35 ±2.268

0.796 ±0.18

1.3 ±0.28

Ni(µg/l) 1.1 ±3.5E-04

0.34 ±9.1E-05

1.2 ±5.7E-04

0.93 ±1.8E-03

0.37 ±8.2E-05

0.64 ±1.3E-03

0.89 ±6.5E-04

0.9 ±3.8E-04

1.4 ±2.3E-03

0.95 ±3.1E-04

0.35

Pb (µg/l) 0.067 ±8.8E-05

0.046 ±3.4E-05

0.08 ±8.7E-05

0.7 ±1.7E-03

0.1 ±8.1E-04

0.1 ±2.1E-04

0.83 ±0.0019

0.039 ±3.0E-05

0.136 ±1.5E-04

0.048 ±3.3E-05

0.04

Zn(µ/l) 3.1 ±1.9E-03

1.4 ±7.2E-04

7.6 ±4.0E-03

3.8 ±6.5E-03

2.1 ±8.5E-05

1.85 ±6.3E-04

3.6 ±2.1E-03

4.4 ±1.2E-03

3.3 ±3.8E-03

5.5 ±0.0012

0.74

Alkalinity mgHCO3/L

20 ±7.2

25.72 ±1.6

26.17 1.72

26.09 ±0.94

25.71 ±6.94

24.35 ±7.5

10.77 ±4.69

66.90 ±18.6

11.66 ±3.2

10.5 ±4.6

21.17 ±58.6

Conductivity (µS/m)

55 ±1.2

65.9 ±0.63

66 ±0.49

65 ±0.17

65 ±1.27

76 ±7.3

31.6 0.98

146 ±2.87

34.6 ±0.531

35.5 ±0.74

43.2

Sulphate(mg/l)

6.47 ±2.3

5.15 ±0.47

7.37 ±4.9

5.32 ±0.33

5 ±2.68

5.73 ±5.9

2.15 ±0.44

13.6 ±4.435

2.16 ±0.416

3.13 ±1.56

1.6

pH 7.2 ±0.24

7.5 ±0.18

7.4 ±0.25

7.4 ±0.13

7.4 ±0.15

7.4 ±0.32

7.3 ±0.25

7.5 ±0.165

7.3 ±0.164

7.03 ±0.17

6.9

Generally, regional water pH in most rivers and stream sampled is neutral to alkaline and

varies from 6.8 to 8.5, (Fig 9a). Streams B15 with an average pH of 7.03 is the lowest in the

drainage basin while streams B2 and B7 with an average pH of 7.5 are the highest (Table: 5).

24

Relatively Low pH values were mostly recorded during the 1st spring flood maximum flow,

summer and sometimes during the 2nd

spring flood recession (Fig. 9a). These seasons

coincide with periods of snow melting and decomposition of organic matter. These are

undoubtedly the main processes regulating water pH. Stream B7 flows over the Avan ore

body, its high pH is due to the weathering and buffering effects of carbonates especially

calcite veins associated with ore body and supracrustal rocks (Barsele Technical Report 2006,

Bark 2007). Besides its relatively high pH, Stream B7 equally has elevated concentrations of

Ca, Mg, SO42-

and elevated conductivity levels which are about 2.5 to about 6.5 times greater

than in all the other streams. The concentration of Ca is generally higher than Mg in all the

streams and suggests that the surrounding bedrocks and hence till are enriched in Ca bearing

minerals like plagioclase and calcite which is generally depleted in Mg. Just like pH, the

lowest concentration levels of Ca and Mg were equally recorded during the 1st spring flood

maximum flow, summer and to a lesser extend 2nd

spring flood recession while elevated

concentrations were recorded during base flow.

Alkalinity varies from 4 HCO3/l in stream B6 and B15 to 85 HCO3/l in Stream B7. Stream 7

has the highest buffering capacity which is about three to seven times higher compared to

other streams in the drainage basin, (Figure 9b). Such a high buffering capacity is due to the

weathering of calcite veins associated with the ore body. Streams B6, B8 and B15 have the

lowest buffering capacity in the drainage and possibly reflect variation in rock type or the

absences of carbonates veins in bedrock.

Generally, sulphate concentrations in all streams sampled were greater than the average

concentration in the Kalix River and could be explained by the rustiness of till in some

location; mainly due to the weathering of fragments of pyrite and sulphide minerals or the

occurrence of clay silt as the dominant fine fraction. An anomalous sulphate concentration

(13.23mg/l) in Stream B7 is due its proximity in to the Avan ore body compared to other

streams in the drainage basin. This ore body is hosted by a granodiorite formation and is also

bounded meta mafic volcanic (Fig 2.) which is an indication that fine till which is normally

the weathering product of such rocks should be enriched in clastic sulphide minerals and dark

clayey. Thus, these sulphides are continuously weathered, oxidized and leached into Stream

B7. Very low sulphate concentration in Stream B8 could be attributed to its location in the

drainage basin. Compared to other streams, Stream B8 is located downs stream and it is the

furthest from Stream B7 and B4 which are closest to the main ore bodies. Distance from the

main ore body also implies that dilution by barren streams should be strong enough to reduce

its persistence in the drainage basin. Dilution by barren water is further supported by the fact

that the lowest sulphate concentrations were recorded during summer and spring flood which

coincide with the melting of snow.

Conductivity varies from 2µS/m in stream B6 to 18µS/m in stream B7. The median

conductivity in stream B7 (15.5 µS/m) is about three to five times higher compared to other

streams in the drainage basin, (Figure 9c). Stream B6, B8 and B15 have the lowest

conductivity levels which is an indication that calcite vein may not be associated with rocks

bordering these streams. It is worth stating that the concentration trend for Ca and Mg

25

correlates with conductivity, (Table 5) and possibly suggests that Ca and Mg together with

sulphate and alkalinity are the main factors controlling the conductivity of these streams.

The concentration of Fe in all streams varies from 0mg/l in streams B2, B3y, B3b and B4 to

0.3mg/l in stream B5, (Figure 9d) and are consistently low compared to the Kalix River with

an average concentration 0.492mg/l, (Table: 5). This deviation is mainly due to occurrence of

mires and swamps concentrating Fe around the Kalix river. Though low, relatively high Fe

concentration was observed during summer, 1st spring flood maximum flow and in some

cases during the 2nd spring flood recession indicating the influence of a slight change in pH

on its mobility. Besides changes in pH, relatively high Fe concentration could also be due to

the release of high Fe concentration at the snow-soil inter face during the late stage of

snowmelt. Stream B5 with an average concentration of 0.137mg/l is most elevated in Fe

possibly because of the oxidation of arsenopyrite and pyrrohtite associated Norra ore body.

Relative high Fe concentration could also be associated to the dominance of mafic volcanic

rocks around Stream B5 (fig 2). The influence of these rock is reflected in till and soil which

are dominantly made up of dark clays , or silty clays possibly containing fragments of Fe-

bearing minerals like olivine, pyroxenes amphiboles and biotite minerals. However, it must

be stressed that the low Fe concentration observed in some streams could be due to the fact

that in such surface waters with abundant oxygen (high Eh) and with a neutral to alkaline pH,

Fe is insoluble but exist mainly as Fe- oxyhydroxide which has a general tendency to form

precipitation barriers for most heavy metal (Rose et al.; 1979). This together with the near

neutral pH of streams in the drainage basin possibly explains the relatively low concentration

of Pb, Ni and Cu in most streams.

Generally, elevated concentrations of As, Cu Ni Pb and Zn in all the streams sampled

somewhat correlate with a relatively low seasonal pH values, base flow and to a lesser extend

with spring flood seasons, and demonstrate the role of a slight drop in pH in the

remobilization of these elements. In most of the unmineralized streams and rivers, the metal

concentration and mobility decrease in the order Pb<Ni<As<Cu<Zn (Fig 10a and 10b),

which is just typical of most surface waters mainly because these metal form free aqueous

species and complexes with SO42-

, (OH)-1

and CO32-

at different pH (Appelo and Postma,

2005 and Hem, 1976). However, in mineralized streams like stream B7, B4 and B2, their

mobility trends decrease in the order Pb<Ni<Cu<Zn<As, or Pb<Ni=Cu<As<Zn (Fig 10c and

10d) and reflect the influence of ore bodies or at least possible ore bodies, mineralized till and

to a lesser extent pH, complexing ligands and sorption processes on their mobility. It is

equally important to consider the fact that As forms mobile complex anions which could

inhibit its adsorption on precipitation barriers and therefore is mobile even at neutral pH,

(Morel and Hering, 1993). Dark clays containing fragments of pyrite, sulphides minerals,

biotite and granodiorite should possibly be the dominant till type around these streams, (Fig 2

and Fig 7b). Thus, the fine fractions in till exposes a large surface area and high cation

exchange capacity for the adsorption of arsenic and other trace metals. It can be said that As

mainly as arsenopyrite is continuously being oxidized and leached into sediments and hence

surface waters (Smelly and Kinniburgh, 2002). It is worth mentioning that the concentration

of As in Stream B7 is 3.8 to about 36 times greater than the average concentration in most

streams sampled and equally correlates with high sulphate, Ca, Mg and conductivity.

26

Stream B4 is closer or flows over the Norra ore body (Fig 3) and its As level is five times

greater than in Stream B5 which flows close to it. Both of streams constitute the main inlets

of Lake Skirträsket. (Fig 5 and table 5). Such variations could be traced from the difference in

rock type and hence till type. It can be seen from (Fig 2) that metasedimentary rocks and

hence sandy silts with fragments of granite, quartz, seem to be dominant around Stream B5

unlike mafic volcanic rocks with fine till around Stream B4. The flow directions or sources of

both streams should equally be considered, (Fig 5) because the nature of the relief around

these streams could greatly influence which direction As leached from the Norra ore body or

from mechanically dispersed till will flow. Thus, As in this case serves as a pathfinder for

Au, and its low concentration in stream B5 possibly delineates the upper limit of the Norra

ore body. Just like Stream B4 and Stream B5, Stream B1 which is closer to Stream B2 is

relatively depleted in As and could be explained by fact that Stream B2 flows from the

southeast of Lake Skirträsket and is bounded by mafic intrusion and possibly till rich in

fragments of mafic volcanic, biotite, massive sulphides and thin covers of soils. Stream B1

constitute the main outlet of Lake Skirträsket is mostly surrounded by till containing

fragments of granite, sand, and quartz which generally have a low heavy metal content, (Fig

5). In the case of B3y and B3b (lake Skirträsket) the near uniform concentration of As

reflects homogenous mixing of barren and mineralized water flowing into Lake Skirträsket.

Stream B15 is located upstream compared to most streams in the drainage basin and appears

to be the furthest from Stream B7 and Stream B4 which are the closest to the ore body. Thus,

its location together with its surrounding rocks, mainly metasedimentary and metagranitoid

(Fig 3) accounts for its low As concentration. River B6 and B8 are the least polluted with As

and their average As concentration near equals the average As concentration in the Kalix

River, (table 5). River B8 is located downstream of B6, and its low As concentration could

mainly be attributed to dilution effect. River B8 is mainly surrounded by glaciofluivial

sediments, granites, sandy silt and metasedimentary rocks which are known to have very low

As concentration. It is equally important to consider the fact that generally in such

oxygenated surface waters with high Eh values, As could equally exist as H2AsO 4- and

could be adsorbed onto Fe (OH)3 at neutral pH (Moore and Ramamoothy 1984). This could

account for low As levels in some of the Streams. Distance from the ore body is equally

worth considering because this could account for the progressive decay in As concentration

and further explains the relatively low As level observed in some streams.

Though depleted in As, Stream B15 has the most elevated levels of Zn, about 7.5 times

greater than the average concentration in the Kalix River and 5.6 times greater than average

concentration in stream B2 with the lowest concentration. Such elevated levels could be

more related to upstream enrichment. It is equally important to consider its relatively low pH

(pH 7.03, table 5) which is somewhat low enough to remobilize Zn. The influence of pH is

further illustrated by the fact that the concentration of Cu and Pb are low or near background

concentration. It could as well be that Stream B15 is being fed by streams with elevated

concentration of Zn.

The concentration of Pb varies from 0 to 0.0068mg/l, (Figure 8i). Generally, its concentration

in all streams sampled is low and could be attributed to the relatively high pH of streams in

the drainage basin. Stream B6 and B3b are most elevated in Pb. Relatively elevated levels in

Stream B6 concentration could further be attributed to Pb sulphide mineralization in addition

to the fact that K-feldspars and micas as common minerals in metasedimentary rocks could

27

equally be enriched in Pb. It is equally important to consider the fact glaciofluivial and

quaternary deposits enriched in these metals could mainly be derived or could be of a

complex origin (fig 2.4a)

The concentration of Cu varies from 0.0002 to 0.009mg/l. Its average concentration is highest

Stream B3y and lowest in Stream B2, (Table5 and Figure 8g). All other streams have near

average concentration or twice the average concentration in the Kalix River and could still be

attributed to the relatively high pH of streams in the drainage basin together with sorption on

to Fe- oxyhydroxide

Nickel concentration varies from 0 to 0.009 mg/l. Its average concentration is highest in

Stream B3y, B3b and B8, (Figure 8h and Table 5). Its concentration in other streams is two to

four times greater than the average concentration in the Kalix River

Figure: 9a pH variation in streams

Figure 9b Variation of alkalinity in stream

6.4

6.6

6.8

7

7.2

7.4

7.6

7.8

8

B1 B2 B3y B3b B4 B5 B6 B7 B8 B15

pH

Streams

pH

0

10

20

30

40

50

60

70

80

90

B1 B2 B3Y B3b B4 B5 B6 B7 B8 B15

Alk

alin

ity

( H

CO

3/l

)

Streams

Alkalinity

28

Figure: 9c Variation conductivity in stream B5

Figure 9d Variation of Fe in streams

Figure 9e Variation of sulphate concentration in stream

1

3

5

7

9

11

13

15

17

19

B1 B2 B3Y B3B B4 B5 B6 B7 B8 B15

Co

nd

uct

ivit

y (m

S/m

Streams

Conductivity

-0.03

0.02

0.07

0.12

0.17

0.22

0.27

0.32

B1 B2 B3Y B3B B4 B5 B6 B7 B8 B15

Fe (

mg/

l)

Streams

Fe

-0.2

4.8

9.8

14.8

19.8

24.8

29.8

B1 B2 B3Y B3b B4 B5 B6 B7 B8 B15

Sulp

hat

e (

mg/

l).

Streams

Sulfate

29

Figure 9f Variation of As concentration in streams

Figure 8gVariation of Cu concentration in streams

Figure 9h Variation of Ni in streams

0

0.005

0.01

0.015

0.02

0.025

0.03

B1 B2 B3Y B3b B4 B5 B6 B7 B8 B15

As

(mg/

l)

Streams

AS

0

0.002

0.004

0.006

0.008

0.01

B1 B2 B3Y B3B B4 B5 B6 B7 B8 B15

Cu

(m

g/l)

Streams

Cu

-0.001

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

0.01

B1 B2 B3y B3b B4 B5 B6 B7 B8 B15

Ni (

mg/

l)

Streams

Ni

30

Figure 9i Variation of Pb in streams

Figure 9j Variation of Zn in streams

Figure10a: Variation of trace metals with time in mineralized stream e.g. 1 Stream B15. Trend is typical

of streams with relatively low As concentration. (Mobility is of the order Zn>Cu>As>Pb)

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

B1 B2 B3y B3b B4 B5 B6 B7 B8 B15

Pb

(m

g/l)

Streams

Pb

-0.005

0

0.005

0.01

0.015

0.02

0.025

0.03

B1 B2 B3y B3b B4 B5 B6 B7 B8 B15

Zn (

mg/

l)

Streams

Zn

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

Me

tal c

on

ten

t (m

g/l)

Dates

Stream B15Zn

Cu

Pb

As

Ni

31

Figure 10b Variation of trace metals with time in unmineralized stream e.g. 2, Stream B1. Trend is

typical of streams with relatively low As concentration. Mobility also of the order Zn>Cu>As>Pb)

Figure 10c Variation of trace metals with time in a typically mineralized stream e.g. 1, Stream B7. Trend

is common for streams with relatively high As concentration. Mobility is of the order As>Zn>Cu>Pb

Figure 10d Variation of trace metals with time in mineralized streams e.g. 2, Stream B7. Trend is

common for streams with relatively high As concentration. Mobility is of the order As>Zn>Cu>Pb

00.0010.0020.0030.0040.0050.0060.0070.0080.009

0.01

Me

tal c

on

ten

t (m

g/l)

Dates

Stream B1Zn

Cu

Pb

As

Ni

0

0.005

0.01

0.015

0.02

0.025

0.03

Me

tal c

on

tan

t(µ

g/l)

Dates

Stream B7

Zn

Cu

Pb

As

Ni

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

Me

tal c

on

tan

t(µ

g/l)

Dates

Stream B4Zn

Cu

Pb

As

Ni

32

Data from the Kalix River serve as a good reference to assess pollution because its metal

concentration going by SEPA standards falls mostly in class 1or 2. In Stream B7 As (18µg/l,

SEPA class4, table 6) is the most polluted in the drainage basin and shows increasing risk for

biological activities. All the other streams have As concentration belonging to class 2 or

class 1 and can thus have little or no effect on biological activities. These observations

clearly support earlier investigation by Pelagia Environmental AB. River B6, As (1.8µg/l,

SEPA class1) and River B8, As (1.6µg/l SEPA, class 1) are unpolluted or have a near

background concentration

Generally Cu and Ni concentration in most streams can be grouped in class 2 and rarely in

class 1. They are the most elevated in the drainage basin after As. Thus, Cu and Ni

concentration in these streams could have little effect on aquatic species. This observation

equally supports earlier investigation by Pelagia Environmental AB.

Zinc, Pb, Cd and Mo can be grouped in class 1. These metals have little or no effect on

biological systems. Generally, Stream, B2 has the lowest base metal concentration, (SEPA

class1or 2, Table 5). It is the least polluted with base metals.

Table 6: Classification of metal content in stream and rivers around Barsele. Classification is based on

standards set by the Swedish environmental Protection Agency (SEPA).

Metal

Streams / Rivers

Class

B1 B2 B3y B3b B4 B5 B6 B7 B8 B15

As 2 2 2 2 2 2 1 4 1 2 1

Cu 2 2 2 2 2 2 2 2 2 2 2

Ni 2 1 2 2 1 1 2 2 2 2 3

Pb 1 1 1 2 1 1 2 1 1 1 4

Zn 1 1 1 or 2 1 1 1 1 1 1 2 5

4.4 Lake water

The concentration of As, S and Zn are marked by a homogenous decrease from surface down

to about 6m in the water column at station A, but not at station B as the concentration of Zn

rather increases within this depth interval. From 6m to about 15m, the concentration of As,

Cu S remain constant whereas the concentration of Zn steadily decrease to a depth of about

12m and then stays constant to a depth of 15m at station B. However, at station A its

concentration steadily increases to a depth of 11cm and then steadily decreases again to a

depth of 15 and becomes stable below this depth (fig 9c & fig 9d). Judging from the lake

water profile of Cu, Mg, Ca, As, Fe, Mn and S it can be said that lake water is somewhat well

mixed. The concentration of Fe and Mn are almost uniform at both sampling stations (fig 9e

and 9f) and points to the near stable oxygenated condition in the water column. However,

slide variations in the concentration of some these elements e.g. Ca, (fig 9a and 9b) from the

surface to about 5m in the water column and could mainly be due to slide differences in water

temperature and oxygen concentration. The concentration of Pb at both sampling stations was

33

very low or below detection possibly because of the high water pH precipitating Pb compared

to other heavy metal.

Figure 9a Variation of Ca and Mg in lake water with depth, station A

Figure 9b Variation of Ca and Mg in lake with depth, station B

Figure 9c variation of Sulphur and trace metal with depth in lake water, station A

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12

De

pth

(m

)

Element (mg/l)

Ca and Mg (station A)

Ca Mg

0

2

4

6

8

10

12

14

16

18

20

0 2 4 6 8 10 12

De

pth

(m

)

Element(mg/l)

Ca and Mg (station B)

Ca Mg

0

2

4

6

8

10

12

14

16

18

0 0.5 1 1.5 2 2.5

De

pth

(m

)

Metals(µg/l) except S (mg/l)

Metal conc (station A)

AS

Cu

Zn

S

34

Figure 9d variation of Sulphur and base metal with depth in lake water, station B

Figure 9e variation of Fe and Mn in lake water with depth, station A

Figure 9f variation of Fe and Mn in lake water with depth, station B

0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5

De

pth

(m)

Element conc (µg/l) except S (mg/l)

Element conc. (station B)As

S

Zn

Cu

Ni

0

2

4

6

8

10

12

14

16

18

0.0001 0.001 0.01 0.1 1

De

pth

(m

)

Fe (mg/l) , Mn (µg/l)

Fe and Mn (station A)

Fe Mn

0

2

4

6

8

10

12

14

16

18

20

0.0001 0.001 0.01 0.1 1

De

pth

(m

)

Fe(mg/l) , Mn (µg/l)

Fe and Mn (station B)

Fe Mn

35

4.5 Lake Sediments

Table 7: Average metal content in Lake Skirträsket compared with average concentration in

unmineralized Lake Kutsasjärvi (Peinerud, 2000). Values in bracket represent maximum concentration.

Element Average concentration in Station A (mg/kg TS)

Average concentration Station B (mg/kg TS)

Average concentration in lake Kutsasjärvi (mg/kg TS)

As 87.08 (139) 74.4 (89.8) 3.82 (6.5)

Cd 1.106 (1.9) 0.65 (1.08) 0.57 (1.12)

Cu 27.94 (39.6) 19.06 (29.2) 14 (17.79)

Hg 0.064 (0.089) 0.055 (0.070) 0.084 (0.28)

Ni 34.48 (41.7) 24.28 (27.8) 7.04 (8.80)

Pb 29.7 (43.8) 20.98 (30.8) 22.79 (49.73)

Zn 173.4 (211 ) 99.36 (143 ) 98.04 (150. 39)

Fe203 (%TS) 3.67 (4.19) 3.35 (3.74) 16.5

MnO (%TS) 0.202 (0.309) 0.16 (0.276) 0.057

Table 7 shows that the average As concentration in Lake Skirträsket is elevated by a factor of

19.5 to 22.8. The average Ni concentration in Lake Skirträsket is elevated by a factor about

3.5 to 5. At sampling station B, the concentration of Pb, Cu, Zn, Cd and Hg are almost equal

to the observed concentration in Lake Kutsasjärvi unlike station B where the concentration of

these metals could be two times higher than the observed concentration. Elevated Fe2O3 in

Lake Kutsasjärvi compared to Lake Skirträsket could be attributed to the mires and swarms

concentrating Fe around the Lake. Such elevated concentrations possibly account for the

elevated concentration observed for some of these metals.

Unlike lake water whose sulphur concentration decreases slightly with depth and becomes

stable at greater depths, sulphur concentration in lake sediments increases linearly with depth

at both sampling station (fig 10c &fig 10d). However, its concentration in water-sediment

interface is higher in station A compared to station B because dissolve sulphur in lake water

is deposited as particulate sulphur in lake sediments. Deep down the lake sediments column

where conditions are more reducing, sulphur migrating from the surface of lake sediments in

the form of SO42-

is progressively reduced to sulphides in the form of H2S. As H2S

progressively scavenges and precipitates base metals, its concentration decreases and only

increases again once these metals have been exhausted. The scavenging effects of H2S is

further illustrated by the fact between 2.5cm-7cm down the sediment column, where the

concentration of sulphur stays constant, the concentration Fe2O3 ,Pb and to a lesser extend Ni

and Cu decreases as well (fig 10j & fig 10k). The above explanation equally account for the

variation in the concentration of Fe2O3 at sampling station B as its concentration increases to

a depth of about 2cm where conditions are weakly oxidizing. This means that within this

depth more ferrous iron is oxidized to ferric iron. The onset of anoxic conditions at depth

greater than 3cm, progressively reduce ferric iron (Fe2O3) to ferrous iron, mainly in the form

of pyrite (fig 10f &fig 10g). However, it must be remembered that digenetic processes taking

place in lake sediments can cause Fe (II), Mn (II) and As (III) which have a general tendency

to move vertically up the lake sediment profile where they are easily oxidized to Fe (III) and

Mn (IV). Once in their oxidized states, Fe2O3 and MnO can scavenge base metal, (Salomons

36

and Förstner, 1984). This possibly explains the high concentration of As and base metals at

the sediment water interface at both sampling stations. High Ni and to a lesser extend Zn at

sediment water interface is due the fact the Fe-Mn oxides are important traps for these metals

(Moore and Ramamoorthy, 1984)

The onset of reducing condition equally explains the decrease in the concentration of MnO

with depth as MnO is progressively reduced to Mn. Once in a reduced state, metal bound to

MnO can be desorbed from sediments which could equally explain the overall increase or

near constant concentration of Ni and Cu in the sediment profile, (fig 10j &fig 10k).

Manganese oxide just like Fe2O3 equally has a high concentration at station A compared to

station B. Its concentration at sampling stations A and B steadily decreases from a depth of 2

and 3cm respectively in the sediment column to a depth of about 8cm where its concentration

stays constant (fig 10f & fig 10j). However at sampling station B the concentration of MnO

increases from the sediment water interface to a depth of about 3cm before steadily

decreasing down the profile. Such an increase points to the more oxidizing nature of

sampling station B compared to station A.

Figure 10a variation of CaO and MgO in lake sediments with depth, station A

Figure 10b variation of CaO and MgO in lake sediments with depth, station B

0

2

4

6

8

10

12

14

16

1 1.2 1.4 1.6 1.8 2

De

pth

(cm

)

MgO and CaO (%TS)

Mgo and Cao (station A)

CaO(%TS) MgO(%TS)

0

2

4

6

8

10

12

14

16

1 1.2 1.4 1.6 1.8 2 2.2

De

pth

(cm

)

CaO and MgO conc (% TS)

CaO and MgO (station B)

CaO MgO

37

Figure 10c Variation of sulphur in lake sediments with depth, station A

Figure 10d Variation of sulphur in lake sediments with depth, station B

Figure 10f Variation of Fe2O3 in lake sediments with depth, station A

0

2

4

6

8

10

12

14

16

1500 1600 1700 1800 1900 2000D

ep

th (

cm)

Sulphur (mg/kg TS)

Sulfur conc (station A)

S

0

2

4

6

8

10

12

14

16

800 1000 1200 1400 1600 1800 2000

De

pth

( c

m)

Sulphur conc ( mg/kg TS)

Sulphur conc (station B)

S

0

2

4

6

8

10

12

14

16

2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3

De

pth

(cm

)

Fe2O3 conc (% TS)

Fe2 O3 conc (station A)

Fe2O3

38

Figure 10g Variation of Fe2O3 in lake sediments with depth, station B

Figure 10h Variation of MnO in lake sediments with depth, station A

Figure 10i Variation of MnO in lake sediments with depth, station B

0

2

4

6

8

10

12

14

16

2.5 3 3.5 4D

ep

th (

cm)

Fe2O3 conc (% TS)

Fe2O3 conc (station B)

Fe2O3

0

2

4

6

8

10

12

14

16

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

De

pth

(cm

)

Mno (% TS)

MnO conc (station A)

MnO

0

2

4

6

8

10

12

14

16

0 0.05 0.1 0.15 0.2 0.25 0.3

De

pth

(cm

)

MnO conc (%TS)

MnO cont (station B)

MnO

39

Figure 10j variation of base concentration in lake sediments with depth, station A

Figure 10k variation of base concentration in lake sediments with depth, station B

Generally, the maximum metal concentrations in Lake Kutsasjärvi are mostly within SEPA

class 1 or class 2, (table 3 and 7). Arsenic is the most elevated and main pollutant in lake

sediments. It can be said that its concentration with depth is not constant throughout the lake

sediment column. For example, from 0 to 7cm at station A, arsenic concentration is grouped

in class 4 (Table 9,) whereas at station B arsenic concentration in class 4 can only be

observed between 0 to 3cm, (Table 8). Next to arsenic is Nickel whose concentration in class

3 is uniform throughout the sediments column at both sampling stations. It possible that Ni

together with As, Cu and to a lesser extend Zn are the most elevated elements in pore water

upwelling to the sediment water-interface. These metals are possibly the most sorped and the

most sensitive to redox processes. The highest average concentration Cu and Ni (class 2)

were recorded in Stream B3y (Lake Skirträsket). Moreover, their average concentrations in

other streams are mostly in class 2, (Table 6). Thus, this possibly accounts for elevated Cu

and Ni concentration in lake sediments. Leads, (SEPA class 1) equally has a uniform

concentration at both sampling stations and possibly imply that Pb is less sensitive to redox

processes or less sorped onto Fe-Mn oxyhydroxide. The concentration of Zinc is uniform

throughout the sediment profile although its concentration is higher at station A (class2)

0

2

4

6

8

10

12

14

16

18

0 0.5 1 1.5 2 2.5

De

pth

(cm

)Metals(µg/l) except S (mg/l)

Element conc (station A)AS

Cu

Zn

S

Ni

0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5

De

pth

(cm

)

Element conc (µg/l) except S(mg/l)

Element conc (station B)As

S

Zn

Cu

Ni

40

compared to station B (SEPA class 1). Station B shows elevated concentration of Cu (SEPA

class 3) from 2cm to greater depths compared to Station A with Cu concentration in class 3

which can only be noticed from 15cm below the sediment surface.

Table 8: Classification of metal content in lake sediments, (Sampling station A). Classification is based on

standards set by the Swedish Environmental protection agency (SEPA)

Class Metals in lake sediments, sampling station A Depth (cm)

As(mg/kgTS) Cu(mg/kgTS)

Ni(mg/kgTS)

Pb(mg/kgTS)

Zn(mg/kgTS)

1

4 2 3 1 2 1

2 4 2or3 3 1 2 2

3 4 3 3 1 or2 2 3

4 3 3 3 1 2 7 5 2 3 3 1 2 15

Table 9: Classification of metal base content in lake sediments. (Sampling station B). Classification is base

on SEPA standards

Class Metals in lake sediments, sampling station B Depth (cm)

As(mg/kgTS) Cu(mg/kgTS)

Ni(mg/kgTS)

Pb(mg/kgTS)

Zn(mg/kgTS)

1

4 1or 2 3 1 1 1

2 4 2 3 1 1 2

3 4 2 3 1 1 3

4 4 2 3 1 1 7 5 2 3 3 1 1 or2 15

It can be said from the above observations that co precipitation with MnO and Fe2O3 besides

a near stable concentration of oxygen in water column accounts for the relatively low As, Cu

and Ni in lake water compared to lake sediments. It must also be said that metal content in

water column would easily increase beyond the permissible level should water pH or oxygen

content be reduced. Such reduced condition could remobilize and trigger an upward

migration of As and heavy metals from the sediment water inter face to the water column.

41

5. Conclusions and Recommendations Gold mineralization in the Barsele is associated with arsenopyrite, pyrrhotite, calcite, chlorite

and biotite and generally has low base metal enrichment. Water interacting with ore body and

mineralized till show seasonal variations in metal content, have a near neutral pH and a good

buffering capacity mainly due to the weathering of calcite veins associated with bedrock.

Bedrock and till composition, proximity to ore body, sorption processes and the near neutral

water pH are the main factors regulating metal content in water. The concentration of Fe in

surface waters is generally low mainly because Fe is precipitated Fe-oxyhydroxide. Sorption

onto Fe-oxyhydroxide seems to limit the mobility of heavy metals in most streams but less on

the mobility of As, possibly because of a high As concentration in mineralized till and a

tendency of As to form mobile complex anion at alkaline to neutral pH. This accounts for its

high mobility in Stream B7 (SEPA class 4) compared to heavy metals. Generally, Zn, Cu, Pb,

Ni, Mo, and Cd are within the tolerance limits, with Stream B2 being the least polluted with

heavy metals while Stream B6 and B8 are the least polluted or unpolluted with As.

Lake water is somewhat uniformly oxygenated and well mixed. This is clearly manifested by

the near uniform and low concentration of Fe Mn, Mg, Cu, Ca and Pb in the water column of

both sampling stations. The concentration of As, S, Cu, Ni and Mo are relatively low and

varies slightly at the surface of water but becomes nearly constant at greater depth.

Metal enrichment in the lake sediment column and in sediment-water-interface is higher at

station A compared to station B and reflects variations in particle size (finer at station A

compared to station B), ground water flow pattern and composition besides variations in

redox processes and the recycling of Fe-Mn from one part of the lake to another. Arsenic

(SEPA class 4) is particularly enriched in lake sediments, in association with precipitation of

Fe-oxyhydroxide. Nickel, (SEPA class 3) and Cu (SEPA class 3 or 2) are equally elevated in

lake sediments. Ni and Cu are possibly the most elevated elements in pore water upwelling to

the sediment water-interface or at least the most sorped and the most sensitive to redox

processes.

Data from the Kalix River and Lake Kutsasjärvi serve as good references to assess pollution

because their metal concentration compared to data from SEPA generally fall in class 1 or 2

which are within the tolerance limits for aquatic systems. However, SEPA data only

quantifies metal pollution and their toxicity levels without considering the chemical form in

which these metals exist in water. It is recommended that further studies to complement this

study should also incorporate ecotoxicological data, or focus on determining the aqueous

speciation of these metals and hence their bio-accessibility to aquatic species. It could equally

be important to understand the flow rate of groundwater because this could influence the

leaching of As and heavy metal from the sediment water interface (e.g. Nikolaos et al., 2004).

Although Lake Skirträsket and mineralized streams have a good buffering capacity, their

metal content could still be upgraded once mining begins because large volumes of rocks will

be exposed to weathering. Thus it is recommended that adequate measures should be taken to

dispose waste rocks and to closely monitor water chemistry.

42

Acknowledgments

I am deeply indebted to the staff of the Environmental department of Northland Resources

AB for their support and for giving me the privilege to do my thesis with Northland

Resources AB. I would also thank Palagia Environmental AB for providing me with regional

water data. Special thanks go to my supervisor Prof. Björn Öhlander for his valuable

suggestions and patience in reviewing the manuscript of this study. I would equally convey

sincere thanks to Ralf and Magnus for the assistance they gave me during field sampling. I

am thankful to my family for their unfailing love, moral and financial assistance during my

studies. Lastly, I hold the staff of the Geosciences’ Division of Luleå University of

Technology in high esteem.

43

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46

Appendices

Appendix 1: lake water station A

Appendix 2: lake water station B

Depth (m) Al (mg/l)

As (µg/l) Ba (µ/l)

Ca (mg/l)

Cd (µ/l)

Co (µ/l)

Cu (µg/l)

Cr (µ/l)

Fe (mg/l)

Hg (µ/l) K (mg/l)

1.5 4.57 2.13 4.09 11.2 0.0275 0.0062 0.318 0.0808 0.0008 <0,002 0.686

6 4.28 1.91 3.99 10.1 0.0175 0.007 0.297 0.0691 0.0009 <0,002 0.603

12 3.85 1.88 4.01 10.3 0.0113 0.0069 0.301 0.0592 0.0008 <0,002 0.609

18 3.69 1.91 4.08 10.4 0.0088 <0.005 0.348 0.0563 0.0011 <0,002 0.593

18.5 3.17 1.91 4.25 10.4 0.0083 0.112 0.273 0.0567 0.0008 <0,002 0.604 Depth (m)

Mg (mg/l)

Mn (µg/l)

Mo (µg/l)

Na (mg/l)

Ni (µg/l)

P (µg/l)

Pb (µg/l)

S (mg/l)

Sr

(µ/l) Zn (µg/l)

1.5 0.851 0.305 0.334 1.02 0.421 <1 <0.1 1.8 25.1 1.13

6 0.764 0.235 0.361 0.935 0.36 <1 <0.1 1.67 23 1.26

12 0.771 0.203 0.307 0.932 0.366 <1 <0.1 1.68 22.8 1.04

18 0.772 0.312 0.31 0.945 0.389 <1 <0.1 1.7 23.2 1.03

18.5 0.776 0.298 0.322 0.942 0.398 <1 <0.1 1.69 23.3 0.822

Depth (m)

Al (mg/l)

As

(µg/l) Ba (µ/l) Ca (mg/l)

Cd

(µ/l)

Co

(µ/l) Cu (µg/l)

Cr

(µ/l) Fe (mg/l)

Hg

(µ/l) K (mg/l)

1.5 4.3 2.13 4.91 11 0.0599 0.0382 0.345 0.0756 0.0011 <0,002 0.674

5 3.8 1.84 4.38 10.3 0.0365 0.0107 0.33 0.0609 0.0008 <0,002 0.651

10 4 1.88 6.78 10.2 0.0323 0.0056 0.352 0.0725 0.0009 <0,002 0.621

15 3.92 1.84 4.57 10.2 0.0254 0.0108 0.33 0.0856 0.0012 <0,002 0.647

16.5 3.83 1.9 4.58 10.4 0.0192 0.0129 0.324 0.0671 0.0011 <0,002 0.652 Depth (m)

Mg (mg/l)

Mn (µg/l)

Mo (µg/l)

Na (mg/l)

Ni (µg/l)

P (µg/l)

Pb (µg/l)

S (mg/l)

Sr

(µ/l) Zn (µg/l)

1.5 0.827 0.324 0.34 0.998 0.423 1.39 <1 1.85 24.6 1.71

5 0.778 0.229 0.312 0.95 0.382 <1 <1 1.74 23 1.45

10 0.77 0.269 0.318 0.957 0.372 1.32 <1 1.73 23.1 2.03

15 0.764 0.288 0.318 0.948 0.376 <1 <1 1.69 23.1 1.32

16.5 0.771 0.323 0.324 0.942 0.324 1.07 <1 1.69 22.9 1.32

47

Appendix 3: lake sediments Station A

Depth (cm)

Hg (mg/kg TS)

LIO (%TS)

MgO (%TS)

MnO (%TS)

Mo (mg/kgTS)

Nb (mg/kg TS)

Ni (mg/kgTS)

P2O5 (%TS)

Pb (mg/kgTS)

S (mg/kgTS)

1 0.0544 13.4 1.18 0.309 <6 6.6 31.9 0.267 40.8 1600

2 0.0682 12.8 1.19 0.31 <6 7.14 33.4 0.267 42.4 1570

3 0.0898 12.9 1.26 0.275 <6 6.697 33.9 0.26 43.8 1640

7 0.0555 12.9 1.32 0.0664 <6 8.38 31.5 0.25 9.68 1650

15 0.0537 15.5 1.31 0.0501 <6 7.34 41.7 0.257 9.2 1930

Depth (cm)

Al2O3 (% TS)

As (mg/kgTS)

Ba (mg/kg TS)

Be (mg/kg TS)

CaO (%TS)

Cd (mg/kg TS)

Co (mg/kg TS)

Cr (mg/kg TS)

Cu (mg/kgTS)

Fe2O3 (%TS)

1 7.15 139 237 1.44 1.96 1.6 8.07 68.3 22.2 3.84

2 7.55 137 268 1.76 1.91 1.18 8.55 71.1 24.5 4.11

3 7.74 136 266 1.59 1.89 0.961 7.96 85.9 25.4 4.19

7 8.21 16 265 1.68 1.98 0.33 5.05 81.1 28 3.39

15 7.96 7.4 274 1.66 2 1.9 5.42 80 39.6 2.84

Depth

(cm)

Sc

(mg/kg TS)

SiO

(% TS)

Sn

(mg/kg TS)

S

(mg/kg TS

TiO2

(%TS)

V

(mg/kg TS)

W

(mg/kg TS)

Y

(mg/kg TS)

Zn

(mg/kgTS)

Zr

(mg/kg TS)

1 9.17 62.3 1.76 139 0.48 57.9 <60 22.6 158 115

2 9.2 62 2.36 136 0.489 58 <60 23 165 111

3 9.72 62 2.13 135 0.515 60.5 <60 24.6 166 116

7 11 61.8 0.889 138 0.557 61.2 <60 27.5 187 109

15 11.1 60.5 0.476 131 0.536 65.2 <60 28.9 191 211

48

Appendix 4: lake sediments station B

NB. Regional water data, and assay data can be obtained from Northland Resources AB

Depth (cm)

Al2O3 (% TS)

As (mg/kgTS)

Ba (mg/kg TS)

Be (mg/kg TS)

CaO (%TS)

Cd (mg/kg TS)

Co (mg/kg TS)

Cr (mg/kg TS)

Cu (mg/kgTS)

Fe2O3 (%TS)

1 8.75 89.8 311 1.78 1.89 0.624 5.31 69.4 14.4 3.4

2 8.44 116 303 1.74 1.89 0.7 6.27 69.2 19.5 3.74

3 8.63 123 313 1.74 1.91 0.737 6.05 72.9 16.6 3.7

7 8.38 36.2 276 1.7 1.86 0.11 3.45 76.4 15.6 3.1

15 7.81 8.5 254 1.64 2.04 1.08 3.81 75.8 29.2 2.82

Depth (cm)

Hg (mg/kg TS)

LIO (%TS)

MgO (%TS)

MnO (%TS)

Mo (mg/kgTS)

Nb (mg/kg TS)

Ni (mg/kgTS)

P2O5 (%TS)

Pb (mg/kgTS)

S (mg/kgTS)

1 0.0537 7.5 1.09 0.188 <6 6.78 22.2 0.203 25.6 939

2 <0.04 8.8 1.13 0.226 <6 7.99 27.1 0.22 30.8 1130

3 0.0701 8 1.13 0.276 <6 7.26 26.5 0.216 27.1 1120

7 <0.04 7.3 1.11 0.0762 <6 6.46 17.8 0.24 11.2 1120

15 0.0422 13.4 1.17 0.0576 <6 7.13 27.8 0.268 10.2 1970

Depth (cm)

Sc ( mg/kg TS)

SiO (% TS)

Sn (mg/kg TS)

Sr (mg/kg TS)

TiO2 (mg/kg TS)

V (mg/kg TS)

W (mg/kg TS)

Y (mg/kg TS)

Zn (mg/kgTS)

Zr (mg/kg TS)

1 8.18 64.6 1.25 176 0.489 47.2 <60 21.2 88.6 150

2 8.82 63.7 1.75 168 0.489 49.9 <60 22.4 98.2 161

3 8.16 64.3 1.41 174 0.495 48.9 <60 21.9 90.2 147

7 9.08 65.2 0.862 164 0.498 46.1 <60 24.2 76.8 173

15 10.2 61.5 0.685 150 0.501 51.8 <60 27 143 157

49