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- Nilsson, Lino, 1988-
(författare)
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Nitrogen Cycling at Cold Climate Mine Sites in Northen Sweden
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)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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- Alakangas, Lena, et al.
(författare)
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Norrbottens malm- och mineralresurs och dess potentiella betydelse för innovation, samhälle och miljö
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)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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| 8. |
- Chlot, Sara, et al.
(författare)
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Effects on nutrient regime in two recipients of nitrogen-rich mine effluents in northern Sweden
- 2013
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Ingår i: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 31, s. 12-24
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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 20:8, s. 5722-5736
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Tidskriftsartikel (refereegranskat)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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- Chlot, Sara, et al.
(författare)
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Modelling nitrogen transformations in waters receiving mine effluents
- 2011
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 409:21, s. 4585-4595
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Tidskriftsartikel (refereegranskat)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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