Understanding process water characteristics and variations is important for ensuring the quality of mineral processing of iron ore. Large amounts of water are used, and the quality of the water can be crucial for processes such as flotation, agglomeration and balling. In this study, changes and variations in process water geochemistry at the Kiirunavaara iron mine have been studied in a time series from 1989 to 2008. Long-term trends at single sampling stations in the process chain as well as changes along the process chain have been studied by statistical methods. This study also quantifies the amounts of major elements such as Ca, Mg, Na, S and Cl carried by process water and by magnetite grain surfaces to the end product, iron ore pellets made from magnetite ore.Ca, S, Na and Cl are the major elements in the process water, accounting for over 80% of the dissolved concentration. Ca has the highest concentrations with an average of 183 mg/l and a maximum of 303 mg/l in the clarifying pond. Corresponding values for S are 162 and 292 mg/l for Cl 132 and 250 mg/l and for Na 88 and 172 mg/l. At all investigated sampling stations (ingoing water and water in the sorting plant, concentration plant, pelletizing plant and clarifying pond) dissolved elemental concentrations increase over the time period. This increase is mainly caused by the increase in production. It is probable that the high concentrations of Ca and S are results of sulfide oxidation and calcite buffering in the drainage area, while the main source of Na, Cl, K and Mg is fluid inclusions liberated during milling of the ore. A prediction of future concentrations of Ca in the process water shows that in future production planning, it will be important to calculate on the basis of higher concentrations in the process water in the whole process chain than are present today. In addition, the amount of colloids (0.22µm – 1kD) in the process water was examined by ultrafiltration. The amounts of various elements sorbed to the magnetite surfaces were estimated by leaching with Milli-Q water, MgCl2, NH4-acetate and Na-acetate. The colloidal fraction was very small, a few percent. For Ca and Mg, sorption to magnetite surfaces was a much more important transport mechanism to the pelletizing process than evaporated process water, but for Na, and S process water was an important carrier.

Forest wildfires are important for the structure and functioning of boreal ecosystems including biogeochemical processes. During the last decades, natural forest fires have been successfully suppressed in Fennoscandia. Therefore, our knowledge on the biogeochemical effects of forest fires is limited. In August 2006, a 1500 ha forest fire occurred near Bodträskfors, northern Sweden. The intensity of the fire varied among vegetation types. Especially in areas dominated by pine forest of the lichen type, vegetation and the humus layer were burnt to a large extent whereas the impact in moist-wet forest patches was less pronounced. Burning and subsequent leaching of plant remainders was expected to affect local surface waters. The main objectives with this thesis were to: 1) investigate the behavior of water quality parameters (pH, conductivity) and dissolved major elements including TOC (Total Organic Carbon) due to leaching of burnt plant remainders and, 2) measure the dissolved concentration and isotopic composition of boron as a potential tracer of forest fires. The project was performed in 2007 – 2009 in a creek draining the burnt area. A creek in a neighboring catchment not affected by the fire was sampled as a reference. Both catchments are characterized by the same type of bedrock and soil cover.The results indicate that leaching of the burnt plant remainders was mainly contributing P, K, Ca and Mg to creek water run-off. This is consistent with the naturally high concentrations of these elements in plant tissue. Na was not leached to any greater extent. Compared to the reference creek, burnt creek concentrations of N were slightly higher and slightly lower for TOC. The pH was ~ 0.5 units lower in the burnt creek during all years of measurement. Conductivity was higher in the burnt creek in 2007 but had decreased to the levels of the reference creek in 2009. Conductivity appeared to be controlled by Ca and Mg concentration as the temporal variations of these parameters/elements were closely correlated. During leaching from burnt plant remainders, P and K concentrations showed similar variation with time. The co-variation of Ca and Mg concentrations marks another behavior but TOC and N each exhibit unique changes of concentration with time. P and K are important nutrients associated to the burnt biomass. This caused extensive leaching of these elements for more than three years after the fire. Ca and Mg are contributed from groundwater to a great extent which was the likely reason for the more short-term post-fire leaching of these elements. As N is also considered an important nutrient it was unexpected that leaching was not as extensive as for P or K. However, the release of N after disturbances in boreal forest catchments has previously been observed to be erratic and depends greatly on the properties of the soil. The hypothesized inhibited release of TOC to the burnt creek was not obvious and the pH difference between both catchments was not considered an effect of the fire. However, since sampling was not conducted for longer than three years after the fire it could not be ruled out that TOC and pH were influenced on a longer term than that.The dissolved B concentrations were substantially higher in the burnt creek in 2007 compared to the reference creek and the isotopic composition (δ11B) was lighter. δ11B was not measured in 2009 but the burnt creek B concentrations were only slightly lower relative to 2007. The measured concentration and isotopic composition of dissolved B in the burnt creek were in line with anomalies of B measured in lake sediments. These anomalies were concluded to be the result of leaching of burnt wood remainders. The lighter B isotopic composition detected in both the present and the previous studies is in line with other findings concluding that forest plants utilize mainly the lighter B isotope (10B) during nutrient uptake from the soil solution. This B is normally released during the winter season inducing a seasonal oscillation of δ11B in the soil solution. The seasonal variation of δ11B was observed in the results from the reference creek. The more extensive leaching of lighter B from the burnt plant remainders most likely caused the overall lighter B isotopic composition and higher B concentrations in the burnt creek relative to the reference creek.

Reclamation of mine sites is a very recent concept on the scale of mining history. It involves the prevention or mitigation of the environmental impacts from mining, and the establishment of sustainable post-mining uses of the land. Many methods have been tested to reduce the contamination from mining waste, but their actual performance depends highly on the nature of the site. In this thesis, the effectiveness of reclamation is investigated at Kimheden open-pit copper mine in Västerbotten, northern Sweden.Sulphide-containing waste rock left from the extraction of the ore was originally dumped on the surface close to the two open pits at Kimheden. The contact of sulphides with water and oxygen induced the generation of copper- and zinc-rich acid mine drainage. Therefore, reclamation of the mine involved backfilling of the mine waste into the open pits and covering with a till composite dry cover including a sealing layer, in order to reduce the oxygen ingress to the waste.Geochemical and geophysical studies conducted in 2009-2010, complemented by monitoring data from the mining company, were interpreted to assess the success of the reclamation. Long-term annual monitoring of the contaminated drainage by the mining company showed that concentrations of copper and zinc added together have decreased by more than 87% since the completion of reclamation in 1996. However, the decrease occurred rapidly, and metal concentrations in the last ten years have remained stable at values that are still not satisfactory for discharge into the environment. Furthermore, pH in the drainage increased only slightly after reclamation. In 2009, seepage water from one of the pits exhibited a pH of 3.0, and copper, zinc and aluminium concentrations of 3 mg/L, 0.3 mg/L and 20 mg/L, respectively. The partial success of the reclamation in mitigating the acid mine drainage may be explained by persistent oxidation of the backfilled mine waste in spite of the application of the dry cover. This would imply that oxygen gas or oxygenated water is still accessing the waste rock, either through the dry cover, or through fractures in the pit walls. These hypotheses were investigated in the field with two different geophysical methods, ground penetrating radar and direct current resistivity.With ground penetrating radar, good-quality image of the sealing layer could be obtained at one of the two backfilled pits, and no evident sign of disturbance in the layer could be found. Resistivity surveys succeeded to image the drainage from the backfill, and suggested that it was seeping out through the dry cover, with a risk of erosion of the sealing layer. Water discharge measurements and resistivity data indicated that the current channelling of the mine drainage to a treatment pond is inadequate, since a large proportion of the contaminated water disappears as groundwater. The interpretation of the resistivity profiles supported by archive data suggested that fractures in the bedrock close to the pits could explain the ingress of oxygen gas or oxygenated water through the pit walls, and would be the primary reason for on-going sulphide oxidation.The results of these studies may help to improve the reclamation of the mine, and in a broader perspective, provide information for reclamation at other sites.

Redox zones are defined by steep gradients of changing concentrations and changing redox potential. They form a transition zone between oxic and anoxic/sulfidic conditions, where nitrate, manganese and iron reduction occurs. These redox zones can be situated in the sediment as well as in the water column. In the Baltic Sea both types are found. In the Bothnian Bay, the northernmost part of the Baltic Sea, the water column is well oxygenated and the redox zone lies within the uppermost sediment (approximately 2 cm in extend). In the Baltic Proper several of the deeper basins are stratified with the redox zone hanging between 75 and 100 m in the water column reaching up to 20 m.The redox-sensitive trace metal manganese can be both electron donor and acceptor in redox zones depending on its oxidation state. Manganese is transformed between the dissolved Mn(II),(III) and the particulate Mn(III/IV). Hence, Mn plays an important role in trace metal cycling across redox zones in natural environments. Manganese particles serve as a carrier for adsorbed trace metals towards the anoxic/sulfidic zone in the water column and as a barrier in the sediment, which restricts dissolved trace elements from diffusing to the oxic zone.In this study water samples (dissolved fraction, <0.22 μm, and particulate fraction, >0.22 μm) from the pelagic redox zone in Landsort Deep, Baltic proper were analyzed. Furthermore, a sedimentary redox zone from the Bothnian Bay has been investigated. A Mn particle peak is detected within the pelagic redox zone at Landsort Deep. A strong correlation between these Mn particles and several oxyanions as Mo, V and W is observed. The oxyanions are adsorbed onto the freshly formed Mn particles in the redox zone, settle with the particles and are released when Mn particles are reduced to Mn2+ and dissolve. This mechanism can act as a pump for trace metals to the sulfidic zone, where the trace metals either can be enriched in the dissolved fraction or form sulfid particles.In the sediment Mn redox cycling leads to enrichment of trace metals in the top layer. The formation of a barrier of Mn-Fe hydroxides restricts trace metal exchange between bottom water and sediment. Freshening of the Bothnian Bay basin has led to an increased sequestering of trace metals in the uppermost sediment. Trace metal proxies show that primary production in the Bothnian Bay has decreased starting approximately 2500 years BP. That led to a shift in the deposition of sulfide forming elements mainly due to the lower input of reactive organic carbon from plankton and to the recent enrichment of elements together with Mn-Fe hydroxides.

The geochemistry of iron (Fe) during freshwater transport and estuarine mixing has been investigated. Espescially the changes in the Fe-isotope signature have been studied. The fate of Fe-isotopes during estuarine mixing has been poorly studied. Sampling was performed in Kalix River, Kalix and Råne estuary, and in the open Bothnian Bay, Northern Baltic Sea. Water samples were filtered with 0.22 μm membrane filters. Both particulate (> 0.22 μm) and colloidal fractions (< 0.22 μm) were analyzed. Iron particles and colloids, with a negative Fe-isotope signature, are formed during spring flood in forested catchments. These Fe complexes are associated with organic carbon (OC), and probably have a mixed oxidation state (Fe(II,III)-OC). Negative colloids are labile and flocculate and/or oxidize during riverine transport. Therefore, no negative colloids are detectable in the estuaries of the open Bothnian Bay. Within the estuaries two types of ˜56Fe signatures were measured: negative particles and positive colloids. The open Bothnian Bay shows a third distinct group of positive particles. This group mirrors the rapid removal of Fe colloids and particles at low salinities. Most of the Fe has been removed from surface water at salinities below 1.0 psu. Data in this study show that the Fe-isotopes can be used to trace the origin and cycling of iron particles and colloids in the boreal landscape.

Prior to the remediation of brownfields, extensive sampling and analysing isdone. The planned and reached measurement uncertainties are seldom asked forcontracting such types of investigations. Therefore they are usually not statednor discussed in the tenders. Requirement for the performance of qualitycontrols generatingusable uncertainty estimates are seldom and no usefuluncertainty levels are either assumed. Such lack ofrequirements means that theuncertainty levels, of theresults used to draw conclusions, are often unknownmaking those conclusions uncertain. A further consequence is the absence ofverification if the used sampling and analytical strategies were appropriate, or ifother approaches should be used in future investigations.The aim of this thesis was to identify the relevant uncertainties in theinvestigation of contaminated soil, showhow they can be assessed by samplingand statistical evaluationsand how appropriate measurement uncertainty can beobtained by choosing analytical as well as sampling strategies.The study concluded that at a minimum, the measurement uncertainty in anenvironmental investigation should be properly estimated with all significantuncertainties listed and assessed, and kept as low aspossible based on availableresources.With forthcoming demands of certified samplers, the quality controls isexpected to increase and thereby theknowledge of uncertainty sources. Goodpractice and the needs for improvement will be identified. Quality controlsampling and statistical methods are available to assess the more commonsources of uncertainty, andsampling and analyticalmethods are applicable toreduce their effect.Increasing the use of more dynamic sampling strategies and analytical methods,the meas / I samband med sanering av förorenade områden utförs miljötekniskaundersökningar som innebär provtagning och analys av jordprover. Planerad ochfaktisk mätosäkerhet i dessa resultat brukar inte efterfrågas i förfrågnings-underlag för svenska miljötekniska undersökningar. Därav följer det naturligt attdessa uppgifter inte brukar specificeras i offerter och att det sällan sker någonkvalitetskontroll av utförda provtagningar som resulterar i en användbarosäkerhetsuppskattning. Det brukar ej heller antas och rapporteras någonanvändbar osäkerhetsnivå. Detta medför att osäkerheten i de resultat somanvänds för att dra slutsatser ofta är okänd vilket leder till osäkra slutsatser.Därför blir det inte heller klarlagt om använda provtagnings- och analys-strategier varit lämpliga eller om ett annat upplägg bör användas vid framtidaundersökningar. Syftet med denna avhandling är att visa vilka osäkerheter som finns i samband med undersökning av förorenade områden, hur de kan uppskattas med hjälp av provtagning och statistiska beräkningar samt hur lämplig mätosäkerhet kan erhållas genom val av provtagnings- och analysstrategi. Slutsatsen är, att som ett minimum bör en miljöteknisk undersöknings mätosäkerhet vara väl uppskattad, med alla viktiga osäkerheter inkluderade eller listade och värderade samt så liten som möjligt utifrån nedlagda resurser. Med kommande krav på certifierad provtagning lär medvetandet om källor till osäkerhet öka när osäkerheterna börjar kontrolleras och utvärderas. Det kommer att framgå vad som fungerar bra och vad som behöver förbättras. Kontroll-provstyper finns för att utvärdera de vanligaste källorna för mätosäkerhet och metoder finns för att minska deras inverkan. Genom att använda en mer dynamisk provtagningsstrategi med smartare användandeav befintliga analysmetoder kan mätosäkerheten minskas genom förtätad provtagning och bättre analyser.

Snowpack properties derived from hydrological models play an important role for many ecological, water resource, and climate applications; such as winter survival of plants, reindeer, small mammals and birds, avalanche hazards, glaciers and polar ice accumulation, growth of sea and lake ices, climate change, snow melt flooding etc. These hydrological models need accurate precipitation phase discrimination schemes to closely portray e. g. energy balance for melt and refreeze cycles, water lost to sublimation, and snow water equivalent within a watershed for the above applications. Precipitation phase is seldom reported from automated surface meteorological stations, so most hydrological models apply an empirical formula based on surface air temperature. There are many different empirical formulas used for precipitation type determination in hydrological models. The most commonly used formulas have one or two fixed air temperatures to separate rain from snow, however, some use more elaborate algorithms. The first part of this study consists of a comparison of common precipitation phase determination schemes to a database of 45 years of three-hour man-made weather observations for nineteen Swedish meteorological stations. These observations consist of surface air and dew point temperatures, precipitation mass and phase (classified as snow, rain, or mixed precipitation). Model schemes using two air temperature thresholds, one threshold all snow (TS) and one all rain (TR) having a linear snow fraction decrease between the thresholds (TS = 0.0˚C; TR = 2.0˚C, or TS = -1.0; TR = 3.0˚C) performed better than using a single rain/snow temperature threshold at all but two of 19 stations. A fitted air temperature dependent snow probability polynomial scheme resulted in similar, but slightly improved classification than a linear decreasing snow fraction approach at 13 of 19 locations. However, using the same empirical formula for all surface weather observations is a flawed technique since surface precipitation phase results from energy exchanges between falling precipitation and air in the lower atmosphere. Different lower atmospheric conditions cause dissimilar precipitation phase probabilities for near-freezing temperatures. Directly measured lower atmospheric conditions are seldom available for remote areas. However, meteorological observations occurring before/after similar air mass boundaries can be assumed to have alike atmospheric conditions which vary from most other observations. Therefore, hydrological models can indirectly account for lower atmospheric conditions. The second part of this study used twenty years of manual observations from eight U.S. weather stations to compare misclassified precipitation proportions when analyzing (a) all precipitation observations together and (b) identified cold air mass boundary observations (CAB) and non-CAB observations separately. The CAB observations were identified by a rapid surface air temperature decrease. Applying a linear decrease in snow fraction method, CAB had a TS (0˚C), and TR (4˚C) 1˚C warmer than non-CAB (-1˚C, 3˚C). Analyzing CAB and non-CAB separately reduced misclassified precipitation by 23%, from 7.0 to 5.4%.

Since the toxicity and mobility of trace metals are related to the metals' speciation, robust methods for trace metal speciation analysis are of great interest. During the last 15 years, hundreds of scientific articles have been published on the development and applications of the diffusive gradients in thin films (DGT) passive sampling technique.In this work the commercially available DGT containing ferrihydrite adsorbent, used for determination of phosphate and inorganic arsenic, was characterised with respect to anionic molybdate, antimonate, vanadate and tungstate determination. Tests were performed in the laboratory as well as in the field. Diffusion coefficients were determined for the anions using two different methods with good agreement. Simultaneous measurements of arsenate were conducted as quality control to facilitate comparison of the performance with previous work. The ferrihydrite-backed DGT was concluded useful for application over the pH-range 4 to 10 for vanadate and tungstate, and 4 to <8 for molybdate and antimonate. At pH values ≥8, deteriorating adsorption was observed.The combination of a restricted pore (RP) version of DGT and the normal open pore (OP) DGT was used for speciation of copper and nickel at three brackish water stations with different salinities in the Baltic Sea. Time series and depth profiles were taken, and complementary membrane- (<0.22 μm) and ultrafiltration (<1 kDa) was conducted. Comparing DGT and ultrafiltration measurements indicated that copper and nickel were complexed. Due to small differences in results between the OP and RP DGTs it was suggested that the complexes were smaller than the pore size of the RP gel (~1 nm) resulting in that both DGTs accumulating essentially the same fraction. Further, there seemed to be a trend in copper speciation indicating higher degree of strong complexation with increasing salinity. The low salinity stations are more affected by fluvial inputs which will likely affect the nature and composition of the organic ligands present. Assuming that copper forms more stable complexes with ligands of marine rather than terrestrial origin would be sufficient to explain the observed trend.

Process water discharged from mine sites may contain elevated concentrations of nitrogen (N) and phosphorus (P), which both are nutrients for algae and aquatic plants. Thus, discharge of nutrient rich mine water can result in algal blooms, eutrophication, oxygen deficiency and changed species composition in the receiving waters. This thesis is focused on the speciation and transformation processes of N and N:P ratios in streams and lakes receiving mine effluents from the Kiruna and Boliden mine sites. In this work, a dynamic biogeochemical model was developed for the clarification pond receiving ammonium-rich mine effluents from the Boliden concentration plant. A number of such models have been developed that simulate N transformations in wastewater stabilization ponds. However, few biogeochemical models have been developed that primarily focus on simulation of processes regulating transport and removal of N in waters receiving mine effluents. The presented model calculates concentrations of six N species and simulates the rate of 16 N transformation processes occurring in the water column and sediment as well as water-sediment and water-atmosphere interactions. A six-year simulation of ammonium concentrations showed stable behaviour over time, and the calibrated model rendered coefficients of determination (R2) of 0.93, 0.79 and 0.86 for the inorganic nitrogen species ammonium, nitrate and organic nitrogen, respectively. This indicates a stable model behaviour. The simulated denitrification rate was on average five times higher than the ammonia volatilization rate, and about three times higher than the permanent burial of sedimentary nitrogen. Hence, denitrification was the most important process for the permanent removal of N. The model can be used to simulate possible measures to reduce the N load and, after some modification and recalibration, it can be applied at other mine sites affected by N-rich effluents. In addition, it was investigated which nutrient that limits bioproduction in the two aquatic systems. Total nitrogen (TN), total phosphorus (TP) and N:P ratios in water, sediment and macrophytes were used to examine (1) spatial variations within the systems, (2) differences between the systems and (3) seasonal variations. The TN content from the discharge point at the Kiruna site was on average about seven times higher than at the Boliden discharge point, while the TP content was 10 times lower than in the discharge point at the Boliden site. Depending on the ammonium concentration in the effluent at the Boliden site, N:P-ratios of the water column shifted from being >22, indicating P-deficiency, to between 9-22, indicating a transition from N to P deficiency (co-limitation). However, water column N:P ratios at the Kiruna site always indicated P deficiency. On the other hand, the N:P ratios of macrophytes revealed that both sites may vary from N to P limitation. These differences are important to consider when establishing a monitoring programme for assessing the environmental influence of nutrient rich mine effluents. Such a programme should include the major N and P species of the water as well as samples of phytoplankton, sediment and macrophytes.

Many countries around the world use coal as fuel for the purpose of power generation. The extraction of coal produces large volumes of waste rock (WR) that are sometimes sulphide rich (principally containing iron sulphides such as pyrite (FeS2) and pyrrhotite (Fe1-xS)), with varying quantities of trace elements such as As, Si, Cu, Zn, Ni, Co, Mo and Cr etc). Such waste is environmentally sensitive due to the risk of oxidation in presence of atmospheric oxygen and water. Sulphide oxidation may result in acidic waters (acid mine drainage, AMD), which often contains high loads of dissolved metals. Coal combustion results in large amounts of fly ash (FA), which also is of environmental concern. However, FA is alkaline and may potentially be used for neutralisation of AMD. Therefore, the AMD producing potential of WR from coal mining and the neutralisation potential of FAs from coal and biomass combustion was studied with the ultimate goal to develop a methodology to decrease the environmental problems related to these materials.WR was sampled form the Lakhra coal field in Pakistan, which has an estimated coal reserve of 1.3 Bton, from lignite to sub-bituminous in quality. The WR samples were characterised by mineralogical and geochemical methods and the acid producing potential was determined by static (Acid Base Accounting) and kinetic (modified humidity cells test) methods. Besides organic material, the WRs are composed of quartz, pyrite, kaolinite, hematite and gypsum with varying amounts of calcite, lime, malladerite, spangolite, franklinite and birnessite. The Lakhra WR has strong potential to generate AMD (-70 to -492 kg CaCO3/ton) and pollute natural waters by leaching of elements such as Cd, Co, Cr, Cu, Ni, Pb, Zn, Fe and SO42-. Three different FAs based on the origin, fuel type and storage methods were studied. They were characterised by mineralogical and geochemical methods, the leachability was studied by batch leaching tests and the potential for buffering acids and neutralisation of AMD was quantified. Fly ash from burning i) brown coal (lignite) in Pakistan (PK), ii) black (bituminous) coal from Finland (FI) and iii) biomass FA provided by a sulphate pulp and paper mill in Sweden (SE) were studied. All ashes contained quarts, PK also iron oxide, anhydrite, and magnesioferrite, FI also mullite and lime, and SE also calcite and anorthite. All ashes were enriched in As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn compared to continental crust, and all ashes had a strong neutralisation potential, the bioash, SE, in particular. The results are encouraging and suggest that it is possible to use FA to mitigate the environmental problems with coal mine WR. Methods for that will be the focus for the continued research.