| 1. |
- Nilsson, Lino, 1988-
(author)
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Nitrogen Cycling at Cold Climate Mine Sites in Northen Sweden
- 2016
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Licentiate thesis (other academic/artistic)abstract
- High nitrogen discharge from mining sites has been an environmental issue that has been closely studied in the recent years. The environmental effects of high nitrogen discharge are mainly eutrophication, but can also lead to changed species composition and algae blooms. Nitrogen is a highly abundant element and is the most abundant element in the atmosphere, where 78% by volume is present as dinitrogen (N2 ). Nitrogen is present in reduced form in all organic life as ammonium (NH4 + ). Nitrogen is also present in reduced form as nitrate (NO3 - ) or nitrite (NO2 - ) in most aquatic systems. Both nitrate and ammonium is contributing to eutrophication problems worldwide and ammonia (NH3 ) is direct toxic in high concentration to certain sensitive aquatic species. Nitrate in high concentration is also direct toxic, both to humans but also to aquatic biota. To trace and quantify different nitrogen transforming processes, their sources and their sinks is called tracing nitrogen cycling and is important due to the environmental effect of nitrogen. Nitrogen is available in many different species and oxidation states which all have their respective geochemistry. This thesis focuses on tracing the complex nitrogen cycle in two different cold climate mining systems in northern Sweden using two different methods. The two studied systems are:The LKAB underground iron ore mine in KirunaBoliden Minerals AB open pit copper ore mine Aitik outside Gällivare Two different approaches were used to trace the nitrogen cycling. The LKAB Kiruna mine was investigated using stable nitrogen isotopes. The isotope analysis showed high capability to trace nitrogen cycling, both quantative and qualitative. We also showed the origin of the isotope signals which gives indication to the different sources of nitrogen in the mine. The presented study shows presence of nitrification, ammonium volatilization and ammonium adsorption to waste rock to occur in the water transport system. The nitrogen cycling in the Boliden Aitik mine was investigated using a nitrogen model which we developed as part of this thesis. The model is based on Yakushevs Redox Layer model (ROLM). The model contains the state variables ammonium, nitrate, nitrite, plankton, phosphate, dead organic material (both particulate and dissolved) as well as oxygen. The nitrogen concentrations in the Boliden Aitik mine was modeled for the clarification pond and showed, in general, low biological activity. The biological mediated reactions such as nitrification, denitrification, phytoplankton growth and grazing were low in relation to natural lake systems
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| 2. |
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| 3. |
- Alakangas, Lena, et al.
(author)
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Norrbottens malm- och mineralresurs och dess potentiella betydelse för innovation, samhälle och miljö
- 2014
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Reports (other academic/artistic)abstract
- Gruvindustrins betydelse för samhällsutveckling och infrastruktur i Sverige och inte minst i Norrbottens län är mycket stor. De geologiska förutsättningarna att hitta nya brytvärda förekomster i Norrbotten är goda. Länet är tillsammans med Västerbotten en av Europas viktigaste regioner för utvinning av metaller. Det syns också i den nyligen framtagna regionala mineralstrategin för Norrbotten och Västerbotten. Visionen för den regionala mineralstrategin: ”Genom långsiktigt hållbart nyttjande av Norrbottens och Västerbottens läns mineralresurser har ytterligare tillväxt skapats i regionen och hela Sverige. Vi har utvecklat och stärkt vår ställning som ledande gruv- och mineralnation.”Eftersom framtidspotentialen för gruvnäringen är mycket god men okunnigheten hos både allmänhet och beslutsfattare om näringens betydelse för innovation och samhällsutveckling är stor, kopplat med en utbredd oro för miljöpåverkan, måste dessa viktiga framtidsfrågor belysas. Med finansiering från Länsstyrelsen i Norrbotten bedrevs därför under första hälften av 2014 en förstudie som syftade till att sammanfatta kunskapsläget om framtidens gruvindustri i Norrbotten. Resultaten av förstudien redovisas i den här rapporten. En viktig slutsats är att det under nästa strukturfondsperiod (med start 2015) behövs ett framtidsinriktat forskningsprogram för att belysa de möjligheter som finns. Denna förstudie utgör grund för en kommande ansökan till strukturfonderna. Kompetensen som finns vid Luleå tekniska universitet, Sveriges centrum för gruvrelaterad forskning och utbildning, bör användas för att studera troliga framtidsmöjligheter och hur de ska kunna användas för att få en så positiv utveckling som möjligt för länet. Projektet bör innehålla följande tre huvudinriktningar, som naturligtvis hör ihop:Vilka malm- och mineralresurser finns det potential för i Norrbotten, och vilka kommer sannolikt att exploateras i framtiden?Vad kommer den exploateringen att ha för betydelse för innovation och samhällsutveckling?Vad kommer den exploateringen att få för miljöeffekter och hur ska man göra för att minska miljöbelastningen?En annan slutsats är att nedlagda gruvområden inte måste ses som förstörd natur. Betydande mervärden som gruvturism skulle kunna skapas om vilja, kreativitet och beslutsamhet finns. Detta är ett givet utvecklingsområde där småföretag och entreprenörer kan göra stor insats om de politiska och myndighetsmässiga förutsättningarna finns. Dessa aspekter skulle också kunna belysas i det föreslagna forskningsprogrammet eller i ett eget projekt.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Chlot, Sara, et al.
(author)
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Effects on nutrient regime in two recipients of nitrogen-rich mine effluents in northern Sweden
- 2013
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In: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 31, s. 12-24
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Journal article (peer-reviewed)abstract
- The question of the limiting nutrient(s) for production of phytoplankton and macrophytes was explored in two contrasting freshwater systems receiving N- and P-rich mine effluents from the Boliden and Kiruna mine sites, northern Sweden. For both sites, total N (TN), total P (TP) and TN:TP mass 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 concentration from the discharge point at the Kiruna site was about seven times higher than at the Boliden discharge point, while the TP concentration was 10 times lower than in the discharge point at the Boliden site. The majority of the studied lakes showed elevated biomass of phytoplankton, with maximum values found in Lake Bruträsket (Boliden). Mining activities have affected the nutrient regime of the two recipients by contributing to elevated TN and TP concentrations and TN:TP mass ratios as well as elevated production of phytoplankton and macrophytes compared to the reference sites. Depending on the NH4 concentration in the effluent at the Boliden site, water column TN:TP mass ratios shifted from being >22, indicating P-deficiency, to between 9 and 22, indicating a transition from N- to P-deficiency (co-limitation). However, water column TN:TP mass ratios at the Kiruna site always indicated P-deficiency, while TN:TP mass ratios of macrophytes indicate that both sites may vary from N- to P-limitation. The study suggests that for the design of efficient monitoring programmes and remediation measures, it is important to consider the major N and P species in water, phytoplankton, sediment and macrophytes.
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| 9. |
- Chlot, Sara, et al.
(author)
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Interaction between nitrogen and phosphorus cycles in mining-affected aquatic systems-experiences from field and laboratory measurements
- 2013
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In: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 20:8, s. 5722-5736
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Journal article (peer-reviewed)abstract
- The main objectives of this study were to (a) study the interaction between N and P cycles in mining-affected aquatic systems and (b) to quantify release rates of sedimentary soluble reactive phosphorus (SRP) that may be related to this interaction. Sediment cores and water from Lake Bruträsket (Boliden, northern Sweden) were collected and a time series of water sampling and flow measurements was conducted in the Brubäcken stream connected to the lake. Factors affecting SRP release were studied in a sediment incubation experiment and water column experiments. Field and laboratory measurements indicated that pH and dissolved oxygen are two important factors for SRP release. At the end of the low-oxygen incubation, an SRP concentration of 56 μg L-1 resulted in a sedimentary flux of 1.1 mg SRP m-2 day-1. This is ∼10 times higher than the flux of 0.12 mg SRP m-2 day-1 obtained from depth integration of vertical SRP profiles measured in the lake, and ∼100 times higher than the external flux of 0.014 mg SRP m-2 d-1 into the lake (based on catchment area). Field measurements indicated that oxidation of organic matter and mining-related chemicals (ammonium and thiosulphates) may result in increased internal SRP flux from the sediment. Increased P loading in the lake as a result of low-oxygen conditions could change water column total nitrogen/total phosphorus ratios from 27 to 17, consequently changing the lake from being P-limited to be co-limited by N and P. The obtained findings point to possible interaction between the cycles of nitrogen (oxygen consumption) and P (flux from sediment) that may be important for nutrient regulation in mine water recipients.
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| 10. |
- Chlot, Sara, et al.
(author)
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Modelling nitrogen transformations in waters receiving mine effluents
- 2011
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 409:21, s. 4585-4595
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Journal article (peer-reviewed)abstract
- This paper presents a biogeochemical model developed for a clarification pond receiving ammonium nitrogen rich discharge water from the Boliden concentration plant located in northern Sweden. Present knowledge about nitrogen (N) transformations in lakes is compiled in a dynamic model that calculates concentrations of the six N species (state variables) ammonium-N (Nam), nitrate-N (Nox), dissolved organic N in water (Norg), N in phytoplankton (Npp), in macrophytes (Nmp) and in sediment (Nsed). It also simulates the rate of 16 N transformation processes occurring in the water column and sediment as well as water–sediment and water–atmosphere interactions. The model was programmed in the software Powersim using 2008 data, whilst validation was performed using data from 2006 to 2007. The sensitivity analysis showed that the state variables are most sensitive to changes in the coefficients related to the temperature dependence of the transformation processes. A six-year simulation of Nam showed stable behaviour over time. The calibrated model rendered coefficients of determination (R2) of 0.93, 0.79 and 0.86 for Nam, Nox and Norg, respectively. Performance measures quantitatively expressing the deviation between modelled and measured data resulted in values close to zero, indicating a stable model structure. The simulated denitrification rate was on average five times higher than the ammonia volatilisation rate and about three times higher than the permanent burial of Nsed and, hence, the most important process for the permanent removal of N. The model can be used to simulate possible measures to reduce the nitrogen load and, after some modification and recalibration, it can be applied at other mine sites affected by N rich effluents.
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| 11. |
- Chlot, Sara, et al.
(author)
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Nitrogen uptake and cycling in Phragmites australis in a lake-receiving nutrient-rich mine water : a 15 N tracer study
- 2015
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In: Environmental Earth Sciences. - : Springer Science and Business Media LLC. - 1866-6280 .- 1866-6299. ; 74:7, s. 6027-6038
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Journal article (peer-reviewed)abstract
- Uptake and cycling of nitrogen (N) in the littoral zone of a lake-receiving nutrient-rich mine water located in Boliden, northern Sweden, was investigated. Stable isotope tracer solutions of 15N as NH4 + (NAM mesocosm) or NO3 − (NOX mesocosm) were added to mesocosms enclosing plants of common reed (Phragmites australis). The 15N abundance in various plant parts was measured at pre-defined time intervals over an experimental period of 22 days. During the course of the experiment, plant parts from the NAM mesocosms were significantly more enriched in 15N than plant parts from the NOX mesocosms. On day 13, Δδ15N values of the fine roots from the NAM mesocosms had reached +8220 ‰, while the maximum Δδ15N value in NOX roots was considerably lower at +4430 ‰. Using 15N values in macrophyte tissues present at the end of the experiment enabled calculations of uptake rates and % of tracer N recovered in the plant (%tracerNrecov). Maximum tracer uptake rates were higher for the NAM mesocosms (1.4 µg g−1 min−1 or 48 mg N m−2 d−1) compared to the NOX mesocosms (0.23 µg g−1 min−1 or 8.5 mg N m−2 d−1). Calculations of %tracerNrecov indicated that 1–8 and 25–44 % of added N was assimilated by plants in the NOX and NAM mesocosms, respectively. Hence, P. australis was more effective in assimilating NH4 +, and a larger portion of the tracer N accumulated in the roots compared to the other plant parts. Consequently, macrophyte N removal is most effective for cold-climate aquatic systems receiving mine water dominated by NH4 +. For permanent removal of N, the whole plant (including the roots) should be harvested.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Gustafsson, Örjan, et al.
(author)
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Colloid dynamics and transport of major elements through a boreal river - brackish bay mixing zone
- 2000
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In: Marine Chemistry. - 0304-4203 .- 1872-7581. ; 71:1-2, s. 1-21
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Journal article (peer-reviewed)abstract
- A range of biogeochemical methodologies were applied to investigate how aggregation processes affected the phase distribution and mixing of Fe, Si, and organic carbon between the Kalix River and the Bothnic Bay, northernmost Baltic Sea (salinity≤3; the low-salinity zone (LSZ) was stretching over 60 km in the spring). During the dynamic springflood conditions studied, small 238U-234Th disequilibria, low sediment trap fluxes, laboratory mixing experiments, as well as results from an independent two-box, two-dimensional mixing model combine to suggest that no significant removal of Fe, Si, or organic C was occurring in the highly-resolved LSZ. While no conclusions may be drawn based solely on property-salinity plots over narrow salinity ranges, apparently linear graphs for Fe and Si over 3 separate years also suggest minimal removal in this regime. At the same time, size distributions both of elements -from cross-flow ultrafiltration - and of bulk suspended solids - from light scattering (photon correlation spectroscopy [PCS]) - indicated that significant aggregation was taking place.The aggregation-without-significant-settling scenario in this low-salinity mixing regime, with a geochemistry similar to that of neighboring Russian Arctic rivers, is hypothesized to result from a comparatively high organic-to-detrital matter characteristic of the aggregates. While first principles would indeed suggest that decreasing electrostatic repulsion during mixing lead to aggregation, a low specific density of mineral-poor amorphous organic aggregates may lead to transport of these authigenic particles further away from the river mouth. The role of detrital "sinkers" on vertical removal of suspended organic matter is discussed in the wider context of scavenging mechanisms in the ocean.
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| 17. |
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| 18. |
- Hellman, Maria, et al.
(author)
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External carbon addition for enhancing denitrification modifies bacterial community composition and affects CH4 and N2O production in sub-arctic mining pond sediments
- 2019
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In: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 158, s. 22-33
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Journal article (peer-reviewed)abstract
- Explosives used in mining operations release reactive nitrogen (N) that discharge into surrounding waters. Existing pond systems at mine sites could be used for N removal through denitrification and we investigated capacity in tailings and clarification pond sediments at an iron-ore mine site. Despite differences in microbial community structure in the two ponds, the potential denitrification rates were similar, although carbon limited. Therefore, a microcosm experiment in which we amended sediment from the clarification pond with acetate, cellulose or green algae as possible carbon sources was conducted during 10 weeks under denitrifying conditions. Algae and acetate treatments showed efficient nitrate removal and increased potential denitrification rates, whereas cellulose was not different from the control. Denitrifiers were overall more abundant than bacteria performing dissimilatory nitrate reduction to ammonium (DNRA) or anaerobic ammonium oxidation, although DNRA bacteria increased in the algae treatment and this coincided with accumulation of ammonium. The algae addition also caused higher emissions of methane (CH4) and nitrous oxide (N2O). The bacterial community in this treatment had a large proportion of Bacteroidia, sulfate reducing taxa and bacteria known as fermenters. Functional gene abundances indicated an imbalance between organisms that produce N2O in relation to those that can reduce it, with the algae treatment showing the lowest relative capacity for N2O reduction. These findings show that pond sediments have the potential to contribute to mitigating nitrate levels in water from mining industry, but it is important to consider the type of carbon supply as it affects the community composition, which in turn can lead to uwanted processes and increased greenhouse gas emissions.
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| 19. |
- Ingri, Johan, et al.
(author)
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Changes in trace metal sedimentation during freshening of a coastal basin
- 2014
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In: Marine Chemistry. - : Elsevier BV. - 0304-4203 .- 1872-7581. ; 167, s. 2-12
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Journal article (peer-reviewed)abstract
- Holocene freshening has turned the Bothnian Bay, northern Baltic Sea into an oligotrophic basin. Sequestering of trace elements has changed significantly during the oligotrophication process. In principle, trace metals have been transferred from permanently buried sulfides to Fe–Mn-oxyhydroxides in the top layers of the sediment. The oxyhydroxide layers restrict the flux of trace metals from the sediment to the oxic bottom water. Hence, Fe–Mn cycling in the suboxic sediment enriches a number of trace metals in the surface sediment. Arsenic, Sn, Ge and Bi show enrichment in the Fe-oxyhydroxide layer, whereas Mo, Cd, Ni, Co, Cu, and Sb are enriched in the uppermost Mn-oxyhydroxide layer. This natural redox cycling in the sediment obscures pollution effects.The oligotrophication process started approximately 3500 years ago, reflected in decreasing deposition of Zn, a proxy for phytoplankton production, and formation of Mn oxyhydroxide layers. Similarly, Ba/Al data indicate a decrease in the pelagic input of plankton. Barium data also suggest that dissolved sulfide in the sediment never reached high concentrations. Germanium is closely related to Ba, suggesting that Ge can be used as a proxy for phytoplankton production. Vanadium, U, Re, and Mo all indicate that the bottom water never has been significantly sulfidic during the last 5500 years. Rhenium data indicate that the organic carbon oxidation rate has decreased during the last 5500 years. Cadmium follows the organic matter distribution, but started to increase 1000 YBP (years before present). The reason for this enhanced input of Cd is unclear.
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| 20. |
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| 21. |
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| 22. |
- Ingri, Johan, et al.
(author)
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Geochemistry of major elements in a pristine boreal river system : hydrological compartments and flow paths
- 2005
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In: Aquatic geochemistry. - : Springer Science and Business Media LLC. - 1380-6165 .- 1573-1421. ; 11:1, s. 57-88
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Journal article (peer-reviewed)abstract
- Once or twice weekly, water sampling was undertaken for a two and a half year period in the Kalix River, northern Sweden. Soil water, groundwater, water in tributaries and mire water were also sampled at several occasions. Samples were filtered and analysed for major dissolved elements and TOC. Although only 5 of the bedrock in the Kalix River drainage basin is situated in the Caledonian mountains (mostly schist, with some outcrops of dolomite and limestone), the chemical composition of the river, at the river mouth, is clearly influenced by water from the mountain areas. High dissolved Ca/Mg ratios in June and July indicate a large influence of water from the mountain areas during summer. The dissolved Si/Mg ratio increases when water from the woodland (bedrock consisting of Precambrian granitoids) predominates during snowmelt in May, but the ratio is low during summer when water from the mountains is increased. However, the low Si concentrations in the mountain areas are probably not primarily the result of the different rocks but more a reflection of the less intense weathering of silicate minerals in the mountains. High Si/Mg ratios are closely related to high TOC. All the major dissolved elements, except TOC, are diluted by snowmelt in May. However, the dilution varies for different elements. Based on the interpretations of major element ratios the melt water discharge in May reflects two major compartments in the woodland; peatland areas and the upper section of the soil. During summer and autumn storm events in the woodland most of the storm water originated from peatland. High K/Mg ratios in the river in May are related to water discharge from the upper section of the till. Low S/Mg ratios in the river indicate an influence of mire water from the woodland both during melt water discharge in May and during increased water discharge in autumn. The Ca/Mg ratios in tributaries in the woodland are consistently lower during melt water discharge compared with values in August. The lower Ca/Mg ratio in May probably reflects water that has been in contact with the B-horizon in the till during spring flood. Data show that the TOC discharged during spring flood originates from two major compartments in the landscape, the upper soil profile and peatland. Storm discharge of TOC during the rest of the year originates mostly from peatland.
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| 23. |
- Ingri, Johan, et al.
(author)
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Iron isotope fractionation in river colloidal matter
- 2006
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In: Earth and Planetary Science Letters. - : Elsevier BV. - 0012-821X .- 1385-013X. ; 245:3-4, s. 792-798
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Journal article (peer-reviewed)abstract
- Temporal variations in the iron isotopic composition, δ56Fe between − 0.13‰ and 0.31‰, have been measured in the suspended fraction in a Boreal river. The major mechanism behind these variations is temporal mixing between two types of particles–colloids, Fe-oxyhydroxides and Fe–C colloids. Data in this study indicate that these two types of colloids have different Fe-isotope composition. The Fe–C colloid has a negative δ56Fe value whereas the Fe-oxyhydroxide colloid is enriched in 56Fe. These two types of colloidal matter have different hydrogeochemical origin. The Fe–C colloid reaches the river during storm events when the upper sections of the soil profile (O and E horizons) are flooded by a rising water table. Colloidal Fe-oxyhydroxides reach the river via inflow and subsequent oxidation of groundwater enriched in dissolved Fe(II).
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| 24. |
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| 25. |
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| 26. |
- Ingri, Johan, et al.
(author)
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Temporal variations in the fractionation of the rare earth elements in a boreal river; the role of colloidal particles.
- 2000
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In: Chemical Geology. - 0009-2541 .- 1872-6836. ; 166:1-2, s. 23-45
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Journal article (peer-reviewed)abstract
- Rare earth element (REE) data from weekly sampling of the filtered (<0.45 μm) and suspended particulate phase during 18 months in the Kalix River, Northern Sweden, are presented together with data on colloidal particles and the solution fraction (<3 kDa). The filtered REE concentration show large seasonal and temporal variations in the river. Lanthanum varied between approximately 300 and 2100 pM. High REE concentration in the filter-passing fraction is related to increased water discharge and there is a strong correlation between the REE concentration, organic carbon, Al and Fe. Physical erosion of detrital particles plays a minor role for the yearly transport of particulate REE in this boreal river system. The suspended particulate fraction, which is dominated by non-detrital fractions, accounted for only 35% of the yearly total transport of La in the river. Approximately 10% of the REE were transported in detrital particles during winter. At spring-flood in May, about 30% of the LREE and up to 60% of the HREE where hosted in detrital particles. Ultrafiltration of river water during spring-flood shows that colloidal particles dominate the transport of filter-passing REE. Less than 5% of the filtered REE are found in the fraction smaller than 3 kDa. The colloidal fraction shows a flat to slightly LREE enriched pattern whereas the solution fraction (<3 kDa) show an HREE enriched pattern, compared with till in the catchment. Suspended particles show a LREE enriched pattern. Data indicate that the REE are associated with two phases in the colloidal (and particulate) fraction, an organic-rich phase (with associated Al-Fe) and an Fe-rich (Fe-oxyhydroxide) inorganic phase. The Ce-anomaly in the suspended particulate fraction in the river shows systematic variations, and can be used to interpret fractionation processes of the REE during weathering and transport. There was no anomaly at maximum spring-flood but during the ice-covered period the anomaly became more and more negative. The temporal and seasonal variations of the Ce-anomaly in the suspended particulate phase reflect transport of REE-C-Al-Fe-enriched colloids from the upper section of the till (and/or from mires) to the river at storm events.
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| 27. |
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| 28. |
- Ingri, Johan, et al.
(author)
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Uptake of alkali and alkaline-earth elements on suspended iron and manganese in the Kalix River, northern Sweden
- 1994
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In: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 58:24, s. 5433-5442
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Journal article (peer-reviewed)abstract
- Scavenging of alkali and alkaline-earth elements by suspended Fe and Mn in the Kalix River, northern Sweden, has been studied for a period of seventeen months. More than 95% (by weight) of suspended nondetrital concentrations of Ca, Mg, and Sr are scavenged on suspended nondetrital Fe throughout all seasons. Barium is correlated to suspended Fe during winter, but during the summer a significant fraction of nondetrital Ba is associated with Mn-rich particles. Porewater profiles for Ca, Mg, and Sr are similar to the dissolved Fe profile, suggesting desorption from a Fe-rich carrier phase. Compared with the river water concentration, Ba is enriched twenty-five times in porewater and shows, together with Mn, a post-depositional subsurface maximum in the solid sediment. The alkali elements Na and K show a linear correlation to suspended nondetrital Fe during the winter. However, the summer concentrations cannot be explained by scavenging onto Fe alone, and sediment and porewater data show no clear association with Fe or Mn. The distribution coefficients for the alkaline-earth elements are two orders of magnitude larger than coefficients obtained for model Fe-oxyhydroxides. This suggests that surface complexation occurs via other functional groups and/or the alkaline-earths are more firmly bound to the natural Fe-rich phase.
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| 29. |
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| 30. |
- Kløve, Bjørn, et al.
(author)
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Groundwater dependent ecosystems : Part I: Hydroecological status and trends
- 2011
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In: Environmental Science and Policy. - : Elsevier BV. - 1462-9011 .- 1873-6416. ; 14:7, s. 770-781
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Journal article (peer-reviewed)abstract
- Groundwater dependent ecosystems (GDEs) include valuable ecosystems such as springs, wetlands, rivers, lakes and lagoons. The protection of these systems and services they provide is highlighted by international agreements, i.e. Ramsar convention on wetlands, and regional legislation, i.e. the European Water Framework Directive. Groundwater provides water, nutrients and a relatively stable temperature. However, the role of groundwater in surface ecosystems is not fully understood. The ecosystem can depend on groundwater directly or indirectly, and the reliance can be continuous, seasonal or occasional. This has implications for the vulnerability of ecosystems, as some may be easily affected by external pressure. Conceptual models and quantitative assessments of how groundwater interacts with the environment are needed. GDEs are also threatened by different land use activities and climate change. Hence, we need to understand how GDEs are affected by changes in groundwater quantity and quality, as severe groundwater changes have been observed in many regions. This study examines key aspects of GDEs (hydrogeology, geochemistry and biodiversity) in order to improve conceptual understanding of the role of groundwater in such ecosystems. The status and baseline of different types of GDEs are discussed, with particular emphasis on past evidence of environmental change and potential thresholds and threats in GDEs in various parts of Europe with different land use, climate and geology
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Nilsson, Lino, 1988-, et al.
(author)
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Modelling tool for predicting and simulating nitrogen concentrations in cold-climate mining ponds
- 2018
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In: Ecological Modelling. - : Elsevier. - 0304-3800 .- 1872-7026. ; 380, s. 40-52
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Journal article (peer-reviewed)abstract
- A nitrogen model was developed with the aim to trace nitrogen cycling in a cold climate-mining pond at the Aitik copper mine in northern Sweden. The model contains 10 state variables and 19 nitrogen cycling reactions. The model also includes sediment and physical properties of the pond, such as evaporation, freezing and thawing. The model was written in Mathworks MATLAB and was calibrated and validated using environmental monitoring data for the clarification pond at the Aitik mine. The data used comprised monthly values of nitrogen speciation, phosphorous and water flow. The model accurately predicts ammonium (r2 = 0.84) and nitrate (r2 = 0.82) concentrations in a time series from February 2012–August 2014. The model did not accurately predict nitrate concentrations (r2 = 0.11), presumably due to high oxygen concentration in the pond water that prevented denitrification in the water column. The transport of organic material to the sediment was also limiting denitrification in the sediment. When allowing denitrification in the water column as well as increasing the rate of transport of organic material to the sediment the nitrate prediction capacity increased to a satisfactory level (r2 = 0.54). A sensitivity analysis for the system showed that the most sensitive reactions for the water column were oxic mineralisation as well as the nitrification rate.
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| 35. |
- Nilsson, Lino, 1988-
(author)
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Nitrogen-cycling tracing methods : Case studies at cold-climate mine sites in northern Sweden
- 2018
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Doctoral thesis (other academic/artistic)abstract
- High nitrogen effluents from mine sites is an environmental issue which has received relatively little attention historically. In recent years a number of studies have showed the environmental effects of high nitrogen discharge to natural water bodies, which include local eutrophication, high risk of acute reducing conditions and changed species composition in the receiving waters. Apart from the direct environmental effects of high nitrogen discharge some forms of nitrogen can be directly toxic- ammonia and nitric gas for instance, and some can be indirectly toxic, for instance nitrate which causes methemoglobinemia in infants if ingested.This thesis shows how the developed nitrogen tracing methods can be applied in complex water transport systems such as in a mining environment. Two main study sites were used in this thesis, the LKAB iron mine at Kiruna and the Aitik copper mine at Gallivare operated by Boliden Mineral AB. The nitrogen tracing methods used in this study are stable isotope analysis, combined nitrogen and oxygen isotope analysis, source partitioning using linear combination of sources, numerical analysis using kinetic nitrogen reaction rates, numerical model verification using stable nitrogen isotopes, and Bayesian statistical models to estimate nitrogen concentrations. The study also demonstrates an experimental method of reducing nitrogen concentrations in the mining pond at the LKAB Kiruna site. The nitrogen reducing method was tested in a small scale mesocosm experiment at the Kiruna site in northern Sweden, where a nitrogen reduction rate of around 0.25 - 0.5% total nitrate per day could be achieved.The nitrogen treatment method consists of fertilising the pond system with small amounts of bioavailable phosphorus. Phosphorus is generally the limiting factor for primary production and in the studied mining systems which have high nitrogen concentrations the phosphorus is assimilated into organic matter almost immediately after fertilisation. The phosphorus is assimilated into phytoplankton (algae) which then settles and is used as a carbon source during anaerobic decomposition (denitrification). The denitrification reaction reduces nitrate into nitrogen gas. This would reduce the nitrogen release from mine sites significantly, since nitrate is the dominant form of nitrogen at the two studied mine sites.Concluding the thesis is a 2.5D model which couples a numerical kinetic nitrogen model with a hydrodynamic model. The hydrodynamic model was the Shallow Water Equations (SWE) model that incorporates wind turbulence, inlets, and outlets as source terms for the water velocities. The two models are coupled via velocity, where the nitrogen model couples via chemical mixing and fluxes are calculated from the water velocities in each model cell. The results of this thesis suggests that nitrogen release from the the Kiruna clarification pond could be reduced significantly via the use of phosphorus fertilisation. This is due to an increased denitrification rate in the pond, and the fact that much of the discharge water from the pond system is recirculated back into the mineral processing plants. The recirculation essentially means that the nitrate in the mine water will have quite a long retention time before being passed out the receiving waters.Although the presented nitrate reduction approach showed promising reduction rates, the potential risk of eutrophication in the receiving waters is high, as the discharge water will contain high levels of nitrogen and potentially also phosphorus. The transport pathways and possible natural attenuation of phosphorus must be thoroughly investigated before the presented nitrate reduction method can be implemented at full scale in mine ponds.
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| 36. |
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| 37. |
- Nilsson, Lino, et al.
(author)
-
Tracing nitrogen cycling in mining waters using stable nitrogen isotope analysis
- 2017
-
In: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 84, s. 41-51
-
Journal article (peer-reviewed)abstract
- We show how we used stable nitrogen and oxygen isotopes in ammonium and nitrate to identify and quantify nitrogen transformation and nitrogen sources at the LKAB mining site in northern Sweden. Stable nitrogen isotope analysis worked as an excellent tool for tracing nitrogen cycling in rapidly moving process waters. The isotope analysis was performed on the mining process waters at seven different key points along the water flow and we identified nitrification, ammonia volatilisation, and ammonium adsorption as nitrogen transformation processes. The source of nitrogen is historically explained as undetonated ammonium-nitrate based explosives. We used nitrate nitrogen and oxygen isotopes to quantify four nitrogen sources in the accumulated water in the mine as well as three sources in an above ground process water reservoir. The nitrate isotope data showed that most of the nitrate (70–80%) in the accumulated water underground originated from a sampling point located close to the surface and only a minor fraction (5–20%) originated directly from undetonated explosives (direct dissolution of NH4NO3 and nitrification of NH4). Nitrate from natural groundwater formed roughly 12% of mine water nitrate. In the above ground process water reservoir isotope data indicated another source of nitrogen coming from undetonated explosives.
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| 38. |
- Paulsson, Oscar, et al.
(author)
-
Algal nutrient limitation and metal uptake experiment in the Åkerberg pit lake, northern Sweden
- 2021
-
In: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 125
-
Journal article (peer-reviewed)abstract
- A microcosm nutrient limitation experiment was conducted in the Åkerberg pit lake, located in Västerbotten, northern Sweden, in the summer of 2018. The microcosms were fertilized with N, P and N and P in combination. Chlorophyll-a concentrations were used to estimate algal growth. Filtered and suspended metal concentrations of the microcosms were compared to see if an increase in algal growth would lead to higher metal uptake. The results show that the microcosms fertilized with N and P had the highest chlorophyll-a concentrations (3–3.4 μg/l). This corresponds to an increase of 9.5–11 times compared to the initial chlorophyll-a concentrations, suggesting that the lake is nutrient poor with regards to both N and P. An increase of the metal concentration in the suspended particulate samples (>0.2 μm) of the microcosms fertilized with both N and P could be observed particularly for the mining-related metals Cd, Co, Ni, and Zn. The uptake of these metals amounted to 2.5–20% (Cd), 2.6–14% (Co), 0.87–1.8% (Ni), and 19–64% (Zn) of their filtered concentrations (<0.2 μm).
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| 39. |
- Paulsson, Oscar, et al.
(author)
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Diel variations in dissolved oxygen concentration and algal growth in the Laver pit lake, northern Sweden
- 2023
-
In: Applied Geochemistry. - : Elsevier Ltd. - 0883-2927 .- 1872-9134. ; 155
-
Journal article (peer-reviewed)abstract
- The diel oxygen technique relying on automated in-situ measurements of dissolved oxygen was used as an indicator of seasonal and diurnal variations of photosynthesis in the circumneutral Laver pit lake in northern Sweden. From July to September 2017, surface water temperature, electrical conductivity, pH, and dissolved oxygen were continuously measured at a time resolution of 30 min using sensors mounted on a floating buoy. The data could be monitored in real-time using a browser-based software and permitted calculation of gross primary production (GPP), net ecosystem production (NEP), and respiration (R) in the lake. The dissolved O2 concentration showed a consistent pattern of diel variations that reached up to 0.5 mg L−1 during the warmer summer period (July–August). Towards the end of August these variations decreased in magnitude and remained at ∼0.1 mg L−1 throughout September. pH showed diel variations that mimicked those of dissolved O2, with maximum daily variations of 0.4–0.5 pH units during July and August. A seven-day moving average of GPP showed a peak during July to mid-August, and the maximum GPP value of 0.55 mg O2 L−1 day−1 is similar to those found in natural oligotrophic lakes. A phytoplankton sample showed a total biomass concentration of 24 μg L−1, with the species Chrysophyceae, Chlorophyta, and Bacillariophyta occurring in the water. Diel oxygen data indicated that respiration by autotrophs and respiration of autochthonous labile organic matter by heterotrophs dominated in the lake, as is often the case in lakes where planktonic primary production is the main supplier of labile organic carbon. A close coupling between R and GPP suggests that nearly all GPP was respired in the epilimnion. The study shows that the diel oxygen technique can be used for real-time monitoring of seasonal and diurnal variations of dissolved oxygen and pH in pit lakes. This would be a useful technique in pit lake remediation projects where fertilization is used to stimulate algal growth and metal sequestering by algae.
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| 40. |
- Paulsson, Oscar, et al.
(author)
-
Modelled impact of climate change scenarios on hydrodynamics and water quality of the Rävlidmyran pit lake, northern Sweden
- 2022
-
In: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 139
-
Journal article (peer-reviewed)abstract
- Predictive modelling for three climate scenarios, based on the three greenhouse gas emission scenarios RCP 2.6, RCP 4.5 and RCP 8.5, was conducted for the Rävlidmyran pit lake, located in Västerbotten, northern Sweden. The model output for pH, temperature, dissolved oxygen, Cl, Fe3+, and Zn during the 10-year period 2090–2099 was compared to the model output during the 10-year period 2006–2015, for which measured meteorological data was used as input. Changes in thermocline, chemocline and water outflow were also evaluated. The results indicate that the water outflow from the pit lake will increase, as well as the number of days when the temperature in the mixolimnion exceeds 12 °C. The largest changes are seen for the highest greenhouse gas emission scenario (RCP 8.5). A small increase in Zn outflow (4.4%) could be observed for the RCP 8.5 emission scenario compared to the RCP 2.6 scenario. The results also indicate that the stratification of the lake is relatively stable, and it is predicted to remain meromictic for all climate scenarios. However, a sensitivity analysis indicates that a reduction of groundwater inflow element concentrations by 25–50% may result in a weakened stratification of the lake. Minor dilution could be observed in the monimolimnion of the lake as the modelled Cl concentration decreased by ∼0.3 mg/L in the RCP 8.5 emission scenario compared to the 2006–2015 period. The Cl concentration was also lower in the RCP 8.5 scenario compared to the RCP 2.6 and RCP 4.5 scenario, both in the mixolimnion and the monimolimnion.
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| 41. |
- Paulsson, Oscar, et al.
(author)
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Pit lake oxygen and hydrogen isotopic composition in subarctic Sweden : A comparison to the local meteoric water line
- 2020
-
In: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 118
-
Journal article (peer-reviewed)abstract
- A local meteoric water line based on rainwater and snow core samples was developed for an area comprising parts of eastern Norrbotten and Västerbotten in northern Sweden. The oxygen and hydrogen isotopic composition of groundwater and water from four pit lakes was compared to the local meteoric water line by line-conditioned excess. The isotopic mass balance method was used to estimate the evaporation over inflow ratio and the residence time of the lakes. The results show that the local meteoric water line for the study area is: δ2H = (7.80 ± 0.09) δ18O + (4.35 ± 1.35) ‰, which is close to the global meteoric water line. The surface water of the four pit lakes all have negative line-conditioned excess values which indicate that they have been affected by evaporation. The groundwater plots on the local meteoric water line making it hard to utilize in a mixing model for a lake where precipitation and groundwater are treated as two different sources. Two scenarios were used to estimate the starting composition of the lakes for the isotopic mass balance method. One was based on the intersection point of the local meteoric water line and the local evaporation line and gave evaporation over inflow ratios ranging from 0.23 to 0.74 and residence times ranging from 7.2 to 44.9 years. The second scenario was based on the weighted average composition of precipitation and gave evaporation over inflow ratios ranging from 0.07 to 0.32 and residence times ranging from 2.8 to 14.9 years.
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| 42. |
- Paulsson, Oscar
(author)
-
Pit lake water quality and hydrology : Insights from case studies and modelling of pit lakes in northern Sweden
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- As extraction techniques are improving an increased number of low grade deposits can be economically mined. However, this also means that the number of open pit mines will increase and as a result the number of pit lakes as well. This is of environmental concern as the pit lakes, depending on the geology and other factors, potentially can have a negative impact on surrounding ecosystems, e.g. through high metal concentrations, low pH, and by affecting the hydrologic system. Sweden has a long history of mining and is one the largest metal suppliers in Europe, and many of the mines are located in the northern part of the country. The project aim was to better understand and be able to predict pit lake water quality and some of the underlying processes affecting it, with a focus on cold climates, where temperatures are low and the lakes are ice covered for prolonged periods of time. The following field measurements were conducted in the Laver and Åkerberg pit lakes: 1) minewall stations measuring metal leaching rates from pit walls, 2) oxygen and hydrogen isotopic composition of precipitation and pit lakes to better understand pit lake hydrology (including also the Udden and Rävlidmyran pit lakes), 3) a nutrient limitation and metal uptake experiment in the Åkerberg pit lake, and 4) a continuously measuring buoy installed in the Laver pit lake where short term fluctuations in water quality parameters could be observed. A bathymetric map of the Åkerberg pit lake was also generated during the project. Additionally, modelling of the Rävlidmyran pit lake was conducted based on three different climate scenarios. Measurements of water quality parameters showed that both the Laver and Åkerberg pit lakes have relatively good water quality, pH 6.1–7.4, specific conductivity 41–352 μS/cm and pH 7.6-7.7, specific conductivity 137–140 μS/cm, respectively, and low concentrations of metals. Algal growth was successfully stimulated in microcosms in the Åkerberg pit lake, through addition of the nutrients N and P in combination. Chlorophyll-a concentrations, which were used to estimate algal growth, were 9.5-11 times higher than at the beginning of the experiment in these microcosms. It was also seen that the metal concentration in the suspended particulate phase increased, suggesting that metals were taken up by algae. In the Laver pit lake measurements from the continuously measuring buoy showed diurnal variations for pH, dissolved oxygen, and temperature. The pH and dissolved oxygen was increasing during daytime, indicating that algal growth was increasing. A local meteoric water line, which can be used to separate sources of water from precipitation, if their isotopic compositions are different, was constructed for the study area (δ2H = (7.80 ± 0.09) δ18O + (4.35 ± 1.35) ‰). It was seen that the groundwater had a similar stable isotopic composition as precipitation, as its composition fell on the local meteoric water line. It was also seen that the studied pit lakes had undergone evaporation as they plotted on a local evaporation line (δ2H = (6.88 ± 0.47) δ18O + (−12.75 ± 5.60) ‰). Residence times were calculated for the pit lakes, ranging from 2.9-44.9 years, using the isotopic mass balance method. Modelling of the Rävlidmyran pit lake suggests that it is fairly stable and will remain meromictic during a modelled 100 year period. No major differences in redox or oxygen levels were observed. The temperature is predicted to increase in the mixolimnion along with a slight decrease in dissolved oxygen concentration. The modelling also indicates that the water outflow from the lake might increase, and as a consequence, a slight increase of metal outflow was observed as well. Based on minewall stations, installed at the Laver and Åkerberg mine sites, leaching rates (µg/m2/week) of metals were estimated. These were used to approximate the total contribution of metals from the pit walls to the pit lakes over the course of a year. A difference in metal leaching could be observed for the two mine sites which could be attributed to the deposit type.
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| 43. |
- Paulsson, Oscar, et al.
(author)
-
Stimulating algal growth through wood ash fertilization in the Åkerberg pit lake, northern Sweden
- 2023
-
In: Applied Geochemistry. - : Elsevier Ltd. - 0883-2927 .- 1872-9134. ; 151
-
Journal article (peer-reviewed)abstract
- Fifteen microcosms were installed in the Åkerberg pit lake for 15 days in the summer season (July) 2021. To stimulate algal growth, the microcosms were fertilized with two P-rich wood ashes, and KNO3. Chlorophyll-a was used as an indicator of algal growth while filtered (<0.2 μm) and particulate suspended element concentrations (>0.2 μm) were used to estimate algal metal uptake. Water quality measurements and water sampling were conducted on three occasions (every five days) and at the start of the experiment to monitor algal growth. The chlorophyll-a concentration in the microcosms fertilized with wood ash increased from 0.3-0.8 μg/L at the start of the experiment to 53–77 μg/L after 15 days. Algal element uptake of filtered concentrations (<0.2 μm) was observed for many elements including, Ni (33–36%), Zn (22–65%) and Cd (22–54%). This suggests that wood ash could be used to stimulate algal growth in pit lakes by acting as a source for P and potentially also other nutrients. The highest chlorophyll-a concentrations were seen on day 10, indicating that a breakdown of chlorophyll-a impacted the measured concentrations, which otherwise could have been higher.
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| 44. |
- Pearson, D.G., et al.
(author)
-
Quantifying micro-niche behaviour in sediments : Precise and accurate measurements of DGT gels by laser ablation high resolution laser ablation ICPMS
- 2006
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In: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 70:18, Suppl. 1, s. A478-
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Journal article (peer-reviewed)abstract
- New developments in micron-scale measurements of trace metals and sulphur contents within sediments by DGT (diffusive gradients in thin-films) have revealed micro-niche structures. The origin of micro-niches is unclear and it is important to understand the relative roles played by inorganic and biological processes in the localised remobilisation of metals. We have undertaken a S and Fe isotope study of micro-niches, to better understand their mechanisms of formation. With their inbuilt pre-concentration, element selection and simple matrix, DGTs are an ideal medium for laser ablation ICPMS. In contrast to analysis of mineral phases, fully matrix-matched standards can be easily made. We have initially concentrated on the measurement of S isotopes and will also present experiments where Fe isotopes have been measured in DGT gels. S and Fe isotopes were measured on a Neptune at mass resolutions of >9000. A New-Wave UP-213 nm laser was used with Ar as the carrier gas. Instrumental mass bias (IMB) for S was corrected for using sample-standard bracketing. Ablation experiments on two S DGT gel standards, 10 Hz, 40% power, 170 μm wide line, scan speed 70 μms-1, show in-run δ34S precisions for DGT gels with 2.1 μmol/cm2 S (3 V of 32S) of <0.2‰ (2SE). There is no observed correlation between δ34S and 32S intensity. Reproducibility on δ34S for individual analytical sessions (4-8 standards) is better than 0.3‰ while the reproducibility over 4 sessions is 0.19‰. Further tests to mimic ablation over micro-niches (continuous ablation across a gel with two isotopic compositions) show similar internal precisions and only slightly worse reproducibility-0.48‰ (2SD; n = 6). The accuracy of the LA δ34S measurements on a BaSO4 gel relative to the reference value of the starting BaSO4, bracketed by a AgI gel of known isotopic composition, is better than 1‰, showing negligible S isotopic fractionation during gel deployment. δ34S variations in micro-niches can be easily resolved at the 1‰ level and 100 μm scale whereas variations in natural micro-niches are expected to be 10‰ or more. Fe measurements, using external normalisation to a 60Ni/61Ni ratio and an exponential law to correct for IMB, suggest internal precisions and external reproducibility of <0.15‰ (2SE) and 0.07‰ (2SD) should be possible.
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| 45. |
- Pekka, Larisa, et al.
(author)
-
Geochemistry of the Kola River, northwestern Russia
- 2004
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In: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 19:12, s. 1975-1995
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Journal article (peer-reviewed)abstract
- The Kola River in the northern part of the Kola Peninsula, northwestern Russia, flows into the Barents Sea via the Kola Bay. The river is a unique place for reproduction of salmon and an important source of drinking water for more than 500,000 people in Murmansk and the surrounding municipalities. To evaluate the environmental status of the Kola River water, sampling of the dissolved (<0.22 μm) and suspended (>0.22 μm) phases was performed at 12 sites along the Kola River and its tributaries during 2001 and 2002. Major (Ca, K, Mg, Na, S, Si, HCO3 and Cl) and trace (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, Ti, and Zn) elements, total and particulate organic C (TOC and POC), N and P were analysed. Comparison with the boreal pristine Kalix River, Northern Sweden, shows that, except for Na, Cl, Al, Cu and Ni, which exceed the concentrations in the Kalix River by as much as 2–3 times, the levels of other major and trace elements are close to or even below the levels in the Kalix River. However, the results also demonstrate that pollutants from the three major sources: (1) the Cu–Ni smelter in Monchegorsk, (2) the open-pit Fe mine and ore concentration plant in Olenegorsk, and (3) the Varlamov, the Medveziy and the Zemlanoy creeks, draining the area of the large agricultural enterprises in the lower part of the watershed, have a major influence on the water quality of the Kola River.
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| 46. |
- Pontér, Simon, et al.
(author)
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Early diagenesis of uranium in lakes receiving deep groundwater from the Kiruna mine, northern Sweden
- 2021
-
In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 793
-
Journal article (peer-reviewed)abstract
- The uranium (U) concentrations and isotopic composition of waters and sediment cores were used to investigate the transport and accumulation of U in a water system (tailings pond, two lakes, and the Kalix River) receiving mine waters from the Kiruna mine. Concentrations of dissolved U decrease two orders of magnitude between the inflow of mine waters and in the Kalix River, while the concentration of the element bound to particulate matter increases, most likely due to sorption on iron‑manganese hydroxides and organic matter. The vertical distribution of U in the water column differs between two polluted lakes with a potential indication of dissolved U supply from sediment's pore waters at anoxic conditions. Since the beginning of exposure in the 1950s, U concentrations in lake sediments have increased >20-fold, reaching concentrations above 50 μg g-1. The distribution of anthropogenic U between the lakes does not follow the distribution of other mine water contaminants, with a higher relative proportion of U accumulating in the sediments of the second lake.Concentrations of redox-sensitive elements in the sediment core as well as Fe isotopic composition were used to re-construct past redox-conditions potentially controlling early diagenesis of U in surface sediments. Two analytical techniques (ICP-SFMS and MC-ICP-MS) were used for the determination of U isotopic composition, providing an extra dimension in the understanding of processes in the system. The (234 U)/(238 U) activity ratio (AR) is rather uniform in the tailings pond but varies considerably in water and lake sediments providing a potential tracer for U transport from the Kiruna mine through the water system, and U immobilization in sediments. The U mass balance in the Rakkurijoki system as well as the amount of anthropogenic U accumulated in lake sediments were evaluated, indicating the immobilization in the two lakes of 170 kg and 285 kg U, respectively.
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| 47. |
- Pontér, Simon, et al.
(author)
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Evaluation of a Multi-Isotope Approach as a Complement to Concentration Data within Environmental Forensics
- 2021
-
In: Minerals. - : MDPI. - 2075-163X. ; 11:1
-
Journal article (peer-reviewed)abstract
- Heavy metal contamination was identified in groundwater monitoring wells surrounding a waste deposit facility at the Rönnskär Cu–Pb–Zn smelter in Skellefteå, Northern Sweden, as well as in brackish water and sediments from the nearby harbor. Following an investigative study of the surrounding area, brackish water from the Baltic Sea and sediments from a nearby harbor were also determined to be contaminated. This study investigated the ranges of isotopic compositions of four elements (Cd, Cu, Pb, and Zn) in smelter materials (ores, products, and waste) and polluted groundwater sediments of the affected area. The study’s objective was to evaluate the variability of the polluting source and identify possible isotope fractionation. This study further assesses the viability of using isotopic information to identify the source of the pollutant. These data were used in combination with multi-element screening analysis and multivariate statistical techniques. Expanding the number of elements utilized in isotope tracing empowers our abilities to decipher the source(s) and the extent of environmental exposure from contamination events related to mining and refining operations.
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| 48. |
- Pontér, Simon
(author)
-
Isotope Ratio and Trace Element Measurements Using Inductively Coupled Plasma – Mass Spectrometry : Method Development and Applications in Environmental Forensics
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- Environmental Forensics is a scientific methodology developed for identifying sources, the timing of release, and transport pathways for potentially hazardous environmental contaminants. It combines a variety of analytical methods with principles derived from disciplines such as chemistry, geology, geochemistry, hydrogeology, and statistics, with the purpose to provide objective scientific and legal conclusions on the source and/or time of a contaminant release. Instrumental development and refining separation schemes have allowed higher quality data to be obtained and played a major role in the recent progress of the field. The use of modern techniques such as inductively coupled plasma sector field mass spectrometry (ICP-SFMS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) for trace and ultra-trace element concentrations and isotope ratio measurements provides Environmental Forensics with new opportunities. The work described in the present thesis has been focused on closing knowledge gaps in the field of Environmental Forensics, including analytical method development as well as processes- and source(s)t-tracing using multiple isotopes in environmental studies. Paper I is dedicated to the assessment of performance of double-focusing, sector field mass spectrometry (ICP-SFMS) for determination of analytes (including technology critical elements (TCE)) at ultra-trace levels in complex matrixes, with a special emphasis on the determination of Au, Ag, Ir, Os, Pd, Pt, Re, Rh, Ru, Sb, and Te. Instrumentation development was performed by optimization and testing different configurations of the ICP-SFMS introduction system as well as various sample preparations, pre-concentration, and matrix separation methods. Factors affecting instrumental sensitivity, contamination risks, reagent purity, spectral interferences, matrix effects, and analyte recovery are discussed. Optimized matrix specific methods were applied to a range of reference and control materials (riverine and brackish waters, seawater, whole blood, serum, and urine). Samples included brackish water and seawater from the Laptev Sea, venous blood, tap water, and snow samples collected in Luleå, northern Sweden. In Paper II an analytical procedure was developed, consisting of high pressure/temperature acid digestion using an UltraCLAVE system followed by a one pass, single column matrix separation allowing the first Cr isotope study in epiphytic lichens and mosses, as well as analysis of chromite and soils by ICP-SFMS and MC-ICP-MS. The overall reproducibility of the method, which was found to be ±0.11‰ (2σ), was assessed by replicate preparation and Cr isotope ratio measurements performed by different operators in multiple analytical sessions over a few months. Results indicated no correlation between soil concentrations and isotopic compositions (R2=0.2), while a strong negative correlation (R2=0.7) between Cr concentrations in lichens and mosses and δ53Cr signatures indicates airborne Cr contribution from local anthropogenic source(s) depleted in heavy isotopes. Chromium isotope data obtained for lichens and mosses indicate the potential of using this approach for tracing and quantifying airborne Cr pollution caused by stainless steel foundries. Paper III evaluates heavy metal contamination in brackish water, groundwater, and sediments collected close to a deposit facility at the Rönnskär Cu–Pb–Zn smelter in Skellefteå, northern Sweden. This study investigates the ranges of isotopic compositions of four elements (Cd, Cu, Pb, and Zn) in smelter process materials (ores, products, and waste), as well as in polluted groundwater and sediments of the affected area. The study’s objective was to evaluate the isotope variability of the polluting source and identify possible isotope fractionation between a source and a sink. This study further assesses the viability of using isotopic information to identify the source of the pollutant in various matrices. Isotope composition data were used as a compliment to multi-element screening analysis and multivariate statistical techniques. Expanding the number of elements utilized in isotope tracing empowers our abilities to decipher the source(s) and the extent of environmental exposure from contamination events related to mining and refining operations. Results show clusters of elements with elevated concentrations and significant inter-element correlations that can be traced practically in all matrices tested (from dust samples to sediments), confirming a link between the source and the polluted environmental compartments. Differences in the relative mobility in the environment for different elements (shown in the example of Re and Mo distribution in sediments) may however affect the usefulness of the elemental ratios in reconstructing the extent and timing of pollution events. Among the isotopes evaluated in this study, radiogenic Pb and stable Zn isotope systems offer the most promising source identification in the area close to the smelter. However, temporal variability in the isotopic composition of the source adds complexity for the Pb isotopes. Numerous post-deposition fractionating processes alter the original source ratios for Cu, Zn, and to a lesser extent, Cd. At larger distances from the source, additional fractionation during element migration and dilution of source-specific signatures with background components makes source tracing more challenging. To fully realize the great promise offered by expanding the number of elements utilized in isotope tracing as a powerful way to decipher sources and fate of environmental exposure, a comprehensive evaluation of both source(s) and background variability, as well as post-depositional fractionation, needs to be an integral part of any Environmental Forensics investigation. Paper IV combines uranium (U) and other trace element concentrations with iron and uranium isotope measurements as a proxy to reconstruct historical changes of U release and accumulation in one tailings pond and two lakes (Mettä-Rakkurijärvi and Rakkurijärvi) receiving deep mine waters in northern Sweden, Kiruna. Uranium is deposited in lake sediments downstream of the mine, with elevated U concentrations in the surface sediments exceeding 55 mg kg-1, a >20-fold increase from the pre-industrial years. The distribution of anthropogenic U between the lakes does not follow the distribution of other contaminants reaching the system with mine waters, with a higher relative proportion of U accumulating in sediments of the second lake. Vertical concentration profiles for redox-sensitive elements as well as Fe isotopic composition were used to re-construct past redox-conditions potentially controlling early diagenesis of U in surface sediments. The isotopic signature of U in surface sediments (activity ratio AR=2.5) is far from that of secular equilibrium. These signatures are a function of time and weathering-induced fractionation, used here as a source signature of U originating in the deep groundwater in the mine. Linear regressions of inverse U concentration in water (dissolved, particulate, and total) versus AR reaffirms a simplified mixing situation with two isotopically distinct sources: 1) a natural source (low U concentration, AR 2.64), and 2) an anthropogenic source (high U concentration, AR ≈1.95). After mixing with mine water from the Rakkurijoki system, the AR of receiving Kalix River water decreases from 2.66 to 2.24. Monitoring data on the surface waters demonstrate the effects of the tributary waters of the Rakkurijoki systems as it discharges into the Kalix River, where the U concentration of the river downstream is more than doubled.
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| 49. |
- Rentz, Ralf, et al.
(author)
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Impact of urban stormwater on sediment quality in an enclosed bay of the Lule River, northern Sweden
- 2009
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In: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 73:13, suppl. 1, s. A1090-
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Journal article (other academic/artistic)abstract
- Sediment samples and porewater of an enclosed bay (Skutviken) affected by stormwater discharge near the centre of Luleå, northern Sweden, were analyzed for major and trace elements and 16 polycyclic aromatic hydrocarbons (PAHs), and compared to a reference site and local till. Among the studied metals, Cd, Cu, Pb and Zn were enriched at Skutviken. The use of trace metal ratios provided indications of pollutant sources for the sediment. Also, the PAH content was enriched, in particular for phenantrene, anthracene, fluoranthene and pyrene, which are regarded as common constituents in stormwater. Pb-210 dating was used to determine historical changes in metal and PAH fixation in the sediment. The bay Skutviken was enclosed by the construction of a road bank in 1962. The enclosure led to reduced water circulation in the bay, which promoted the occurrence of anoxic conditions with sulphate reduction within the bay. As a consequence of these conditions, metals are trapped in the sediments as sulphides. This study suggests that enclosed bays with restricted water circulation may be efficient traps for urban pollutants. In areas with postglacial rebound, where such bays are common, enclosure may have an important impact on water and sediment qualities. Due to the postglacial uplift, presently water covered sediments may rise above the groundwater level in the future. These sediments may then become a secondary pollution source if metal sulphides are oxidized.
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- Rentz, Ralf, et al.
(author)
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Impact of urban stormwater on sediment quality in an enclosed bay of the Lule river, northern Sweden
- 2011
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In: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 218:1-4, s. 651-666
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Journal article (peer-reviewed)abstract
- Sediment and porewater samples from an enclosed bay receiving stormwater discharge (Skutviken) near the centre of Luleå, northern Sweden were analysed for major and trace elements and 16 polycyclic aromatic hydrocarbons (PAHs). Among the studied metals Cd, Cu, Pb and Zn were enriched at Skutviken. Also, the PAH content was enriched, in particular for phenantrene, anthracene, fluoranthene and pyrene which are regarded as common constituents in stormwater. The use of trace metal ratios provided indications about pollutant sources for the sediment. Cs-137 dating was used to determine historical changes in metal and PAH fixation in the sediment. The bay Skutviken is enclosed through the construction of a road bank since 1962. The enclosure led to reduced water circulation in the bay that promotes the occurrence of anoxic conditions with sulphate reduction within the bay. As a consequence of these conditions, metals are trapped in the sediments as sulphides. This study suggests that enclosed bays with restricted water circulation may be efficient traps for urban pollutants, reducing the present-day input of pollutants to the sea. In areas with postglacial land uplift, where such bays are common, bay sediments are a potential future source of pollutants when uplift results in erosion and oxidation of the sedi
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