| 1. |
- Temnerud, Johan, et al.
(författare)
-
Spatial patterns of some trace elements in four Swedish stream networks
- 2013
-
Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 10, s. 1407-1423
-
Tidskriftsartikel (refereegranskat)abstract
- Four river basins in southern Sweden, with catchment sizes from 0.3 to 127 km(2) (median 1.9), were sampled in October 2007. The 243 samples were analysed for 26 trace elements (Ag, As, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Ga, Ge, In, La, Li, Mo, Ni, Pb, Sb, Se, Sn, Tl, Ti, U, V and Zn) to identify spatial patterns within drainage networks. The range and median of each element were defined for different stream orders, and relationships to catchment characteristics, including deposition history, were explored. The sampling design made it possible to compare the differences along 40 stream reaches, above and below 53 stream junctions with 107 tributaries and between the 77 inlets and outlets of 36 lakes. The largest concentration differences (at reaches, junctions and lakes) were observed for lakes, with outlets usually having lower concentration compared to the inlets for As, Ba, Be, Bi, Cd, Co, Cr, Ga, Ge, Ni, Pb, Sn, Ti, Tl, U, V and Zn. Significantly lower concentrations were observed for Cd and Co when comparing headwaters with downstream sites in each catchment. Common factor analysis (FA) revealed that As, Bi, Cr, Ga, Ge, Tl and V co-vary positively with Al, Fe and total organic carbon (TOC) and negatively with La, Li and pH. The strong removal of a large number of trace elements when passing through lakes is evident though in the FA, where lake surface coverage plots opposite to many of those elements. Forest volume does not respond in a similar systematic fashion and, surprisingly, the amount of wetland does not relate strongly to either Fe or TOC at any of the rivers. A better understanding of the quantitative removal of organic carbon and iron will aid in understanding trace element fluxes from landscapes rich in organic matter and iron.
|
|
| 2. |
|
|
| 3. |
- Angeler, David, et al.
(författare)
-
Managing ecosystems without prior knowledge: pathological outcomes of lake liming
- 2017
-
Ingår i: Ecology and Society. - 1708-3087. ; 22
-
Tidskriftsartikel (refereegranskat)abstract
- Management actions often need to be taken in the absence of ecological information to mitigate the impact of pressing environmental problems. Managers counteracted the detrimental effects of cultural acidification on aquatic ecosystems during the industrial era using liming to salvage biodiversity and ecosystem services. However, historical contingencies, i.e., whether lakes were naturally acidic or degraded because of acidification, were largely unknown and therefore not accounted for in management. It is uncertain whether liming outcomes had a potentially detrimental effect on naturally acidic lakes. Evidence from paleolimnological reconstructions allowed us to analyze community structure in limed acidified and naturally acidic lakes, and acidified and circumneutral references. We analyzed community structure of phytoplankton, zooplankton, macroinvertebrates (littoral, sublittoral, profundal), and fish between 2000 and 2004. Naturally acidic limed lakes formed communities that were not representative of the other lake types. The occurrence of fish species relevant for ecosystem service provisioning (fisheries potential) in naturally acidic limed lakes were confounded by biogeographical factors. In addition, sustained changes in water quality were conducive to harmful algal blooms. This highlights a pathological outcome of liming lakes when their naturally acidic conditions are not accounted for. Because liming is an important social-ecological system, sustained ecological change of lakes might incur undesired costs for societies in the long term.
|
|
| 4. |
- Badian, Reza A., et al.
(författare)
-
Wide-field mosaics of the corneal subbasal nerve plexus in Parkinsons disease using in vivo confocal microscopy
- 2021
-
Ingår i: Scientific Data. - : Nature Portfolio. - 2052-4463. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- In vivo confocal microscopy (IVCM) is a non-invasive imaging technique facilitating real-time acquisition of images from the live cornea and its layers with high resolution (1-2 mu m) and high magnification (600 to 800-fold). IVCM is extensively used to examine the cornea at a cellular level, including the subbasal nerve plexus (SBNP). IVCM of the cornea has thus gained intense interest for probing ophthalmic and systemic diseases affecting peripheral nerves. One of the main drawbacks, however, is the small field of view of IVCM, preventing an overview of SBNP architecture and necessitating subjective image sampling of small areas of the SBNP for analysis. Here, we provide a high-quality dataset of the corneal SBNP reconstructed by automated mosaicking, with an average mosaic image size corresponding to 48 individual IVCM fields of view. The mosaic dataset represents a group of 42 individuals with Parkinsons disease (PD) with and without concurrent restless leg syndrome. Additionally, mosaics from a control group (n = 13) without PD are also provided, along with clinical data for all included participants.
|
|
| 5. |
- Bergknut, Magnus, et al.
(författare)
-
Modelling the fate of hydrophobic organic contaminants in a boreal forest catchment : a cross disciplinary approach to assessing diffuse pollution to surface waters
- 2010
-
Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 158:9, s. 2964-2969
-
Tidskriftsartikel (refereegranskat)abstract
- The fate of hydrophobic organic compounds (HOCs) in soils and waters in a northern boreal catchment was explored through the development of a chemical fate model in a well-characterised catchment system dominated by two land types: forest and mire. Input was based solely on atmospheric deposition, dominated by accumulation in the winter snowpack. Release from soils was governed by the HOC concentration in soil, the soil organic carbon fraction and soil-water DOC content. The modelled export of selected HOCs in surface waters ranged between 11 and 250ng day(-1) during the snow covered period, compared to 200 and 9600ng/d during snow-melt; highlighting the importance of the snow pack as a source of these chemicals. The predicted levels of HOCs in surface water were in reasonable agreement to a limited set of measured values, although the model tended to over predict concentrations of HOCs for the forested sub-catchment, by over an order of magnitude in the case of hexachlorobenzene and PCB 180. This possibly reflects both the heterogeneity of the forest soils and the complicated and changing hydrology experienced between the different seasons.
|
|
| 6. |
- Bolou-Bi, Bolou Emile, et al.
(författare)
-
Use of stable Mg isotope ratios in identifying the base cation sources of stream water in the boreal Krycklan catchment (Sweden)
- 2022
-
Ingår i: Chemical Geology. - : Elsevier. - 0009-2541 .- 1872-6836. ; 588
-
Tidskriftsartikel (refereegranskat)abstract
- The knowledge of the sources of base cations in stream water is a prerequisite to assess potential effects of changing environmental conditions such as changing rainfall, weathering or groundwater flows on cation export with stream water. This study use stable Mg isotopes to identify potential sources in the well-studied catchment of Krycklan located on gneissic bedrock covered by quaternary sediments in Sweden. Samples were collected from open filed rain, throughfall, stream, soil, rock and litterfall. The delta Mg-26 values of these samples was determined and the contributions of different sources to Mg fluxes in the stream were determined from the variation of the Mg isotope and Sr / Mg ratios. The results show an overall variation of 1.10 parts per thousand between all samples. In addition, Magnesium isotope ratios varied little in the streamwater and in soil solution, except during snowmelt periods during which a large portion of the annual runoff occurs. Magnesium in the streamwater is explained as a mixture of three pools (open field rain, soil solution and groundwater) with the latter two influenced by catchment processes. Outside the snow-melt period, Mg in streamwater mainly derived from the groundwater, assumed to be mineral weathering signature in this catchment, with a contribution ranging from 12 to 63% to Mg fluxes. Open field rain dominates Mg fluxes in streamwater during spring flood (0 to 78%) and may contribute significantly during larger summer and autumn rainfall events. Soil solution input to streamwater range from 16 to 59% of Mg fluxes in streamwater. Our results demonstrate that delta Mg-26 values together with Mg concentrations and Sr/Mg ratios can be used to constrain the Mg sources of stream water and quantify weathering release rates.
|
|
| 7. |
- Campeau, Audrey, et al.
(författare)
-
Sources of riverine mercury across the Mackenzie River Basin; inferences from a combined Hg C isotopes and optical properties approach
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 806, s. 150808-150808
-
Tidskriftsartikel (refereegranskat)abstract
- The Arctic terrestrial environment harbors a complex mosaic of mercury (Hg) and carbon (C) reservoirs, some of which are rapidly destabilizing in response to climate warming. The sources of riverine Hg across the Mackenzie River basin (MRB) are uncertain, which leads to a poor understanding of potential future release. Measurements of dissolved and particulate mercury (DHg, PHg) and carbon (DOC, POC) concentration were performed, along with analyses of Hg stable isotope ratios (incl. ∆199Hg, d202Hg), radiocarbon content (∆14C) and optical properties of DOC of river water. Isotopic ratios of Hg revealed a closer association to terrestrial Hg reservoirs for the particulate fraction, while the dissolved fraction was more closely associated with atmospheric deposition sources of shorter turnover time. There was a positive correlation between the ∆14C-OC and riverine Hg concentration for both particulate and dissolved fractions, indicating that waters transporting older-OC (14C-depleted) also contained higher levels of Hg. In the dissolved fraction, older DOC was also associated with higher molecular weight, aromaticity and humic content, which are likely associated with higher Hg-binding potential. Riverine PHg concentration increased with turbidity and SO4 concentration. There were large contrasts in Hg concentration and OC age and quality among the mountain and lowland sectors of the MRB, which likely reflect the spatial distribution of various terrestrial Hg and OC reservoirs, including weathering of sulfate minerals, erosion and extraction of coal deposits, thawing permafrost, forest fires, peatlands, and forests. Results revealed major differences in the sources of particulate and dissolved riverine Hg, but nonetheless a common positive association with older riverine OC. These findings reveal that a complex mixture of Hg sources, supplied across the MRB, will contribute to future trends in Hg export to the Arctic Ocean under rapid environmental changes.
|
|
| 8. |
- Cascone, C., et al.
(författare)
-
AbspectroscoPY, a Python toolbox for absorbance-based sensor data in water quality monitoring
- 2022
-
Ingår i: Environmental Science. - : Royal Society of Chemistry (RSC). - 2053-1400 .- 2053-1419. ; 8:4, s. 836-848
-
Tidskriftsartikel (refereegranskat)abstract
- The long-term trend of increasing natural organic matter (NOM) in boreal and north European surface waters represents an economic and environmental challenge for drinking water treatment plants (DWTPs). High-frequency measurements from absorbance-based online spectrophotometers are often used in modern DWTPs to measure the chromophoric fraction of dissolved organic matter (CDOM) over time. These data contain valuable information that can be used to optimise NOM removal at various stages of treatment and/or diagnose the causes of underperformance at the DWTP. However, automated monitoring systems generate large datasets that need careful preprocessing, followed by variable selection and signal processing before interpretation. In this work we introduce AbspectroscoPY (“Absorbance spectroscopic analysis in Python”), a Python toolbox for processing time-series datasets collected by in situ spectrophotometers. The toolbox addresses some of the main challenges in data preprocessing by handling duplicates, systematic time shifts, baseline corrections and outliers. It contains automated functions to compute a range of spectral metrics for the time-series data, including absorbance ratios, exponential fits, slope ratios and spectral slope curves. To demonstrate its utility, AbspectroscoPY was applied to 15-month datasets from three online spectrophotometers in a drinking water treatment plant. Despite only small variations in surface water quality over the time period, variability in the spectrophotometric profiles of treated water could be identified, quantified and related to lake turnover or operational changes in the DWTP. This toolbox represents a step toward automated early warning systems for detecting and responding to potential threats to treatment performance caused by rapid changes in incoming water quality.
|
|
| 9. |
|
|
| 10. |
- Drakare, Stina, et al.
(författare)
-
Fokus på Mälaren 2020 : sammanfattande resultat från miljöövervakning och forskningsprojekt knutna till samarbetet mellan SLU och Mälarens vattenvårdsförbund
- 2021
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Samarbetet mellan Mälarens vattenvårdsförbund (MVVF) och Sveriges lantbruksu-niversitet (SLU) fortsätter. Under 2020 påverkade pandemin möjligheterna att ses fysiskt under MVVF:s årsstämma och höstens Mälarseminarium. Vi lyckades hålla Mälarseminariet och några Mälarinarier som digitala möten vilka var välbesökta. Även miljöövervakningen kunde genomföras som planerat. Kännetecknande för 2020 var den milda vintern som inledde året med mycket ne-derbörd i form av regn. Det gjorde västra och nordöstra delarna av sjön grumliga under vår och försommar. Det är svårt att säga om det tydligt påverkade övriga mätvärden. Totalfosforhalterna var något högre än året innan vilket skulle kunna vara en effekt, men syrgashalterna i bottenvattnet var i stället bättre än året innan. Det verkar inte som att sedimentationsprocesser av det grumliga vattnet generellt påverkade syrgashalterna negativt. Statusbedömningen visar att stationer med måttlig status dominerar. I år hade fyra av 33 provtagna stationer god ekologisk status. Det är något bättre än året innan då bara två stationer hade god status. I år visas som vanligt resultat från Crosslink-projektet som visat att trädbevuxna kantzoner är positivt för livet i bäcken. Två artiklar och en film är nyheter för året från detta projekt som just avslutats. Flera doktorander har disputerat under våren och deras resultat från studier av organiska miljöföroreningar i Mälaren samt hur man kan rena bort dem i vattenverken har presenterats. Nytt för i år är att vi visar resultat från forskning om det viktiga växtnäringsämnet fosfor som man vill be-hålla på land där den gör nytta för gröda istället för att göda algblomningar i sjön. Flera projekt studerar de processer som förklarar hur fosforläckage till vatten sker samt hur man kan stoppa upp dem på vägen genom åtgärder i form av våtmarker och även genom att odla musslor i sjön. Årets studentprojekt är delvis kopplade till forskningen och har bland annat handlat om reningstekniker för dricksvatten för att få bort organiska ämnen av flera typer, analys av miljöföroreningar i sjöns tillrinnande vatten, och modellering av hur or-ganiskt material rör sig i sjön.
|
|
| 11. |
- Ejhed, Helene, et al.
(författare)
-
Feasibility study of net load of metals : Particulate fraction and retention of metals in lakes and rivers
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Belastning av metaller på vattenmiljön beror på bruttobelastning från primära och sekundära källor, men även på transport och fastläggning av metallerna inom vattenmiljön. Målet i denna studie var att undersöka möjligheten att använda retentionsmodeller/metoder för att beräkna nettobelastning av metaller på nationell skala med relativt hög upplösning. Detta för att uppfylla krav på internationell rapportering från Sverige. I denna studie har fokus lagts på litteraturstudier av retentionsprocesserna av metaller, test av två retentionsmodeller och en massbalansmetod. Dessutom har speciellt fokus lagts på att tillföra kunskap om partiklar, kolloider och lösta former av metaller i svenska vattendrag och sjöar.Studier av metallretention som finns redovisade i litteraturen visar att det är stor variation i resultaten, från ett par procent upp till nära 100 %. Retentionen är i de flesta studier fördelad enligt: Pb>Cd, Zn, Cu> Ni, Cr. Retentionen i Mälaren har i en studie beräknats till max 60 % för Cd , 50 % för Zn och 30 % för Cu. I en annan studie har retentionen i Vättern beräknats för Cd till 60 % och för Hg till 97 %. Avrinningsområdena till de stora sjöarna är inte fullständigt övervakade med avseende på tillförseln av metaller, vilket innebär att tester av retentionsmodellerna inte kunde genomföras i denna studie. Fastläggning av metaller sker genom lagring i sedimenten. Flera artiklar omfattar framgångsrik användning av uppehållstid för vattnet för att beskriva retentionen med modeller och pekar på vikten av kornstorlek i sediment samt mängden partikulärt bundna metaller. Fortsatt arbete bör fokusera på de parametrarna.Den partikulära fraktionen av metallerna Al, Fe, Ni, Cu, Zn och Pb i svenska sjöar och vattendrag har undersökts i denna studie baserat på två metoder; empirisk regression med linjär regression och PLS analys, respektive kemisk speciering med hjälp av programmet VisualMinteq. Linjär regression visades vara den mest användbara metoden för att beräkna partikulärt bunden fraktion av metallerna och bör användas tills att en förbättrad kemisk karakterisering av metallerna blir tillgänglig. Regressionsmetoden fungerar bra för att bestämma partikulär koncentration av Al, Fe och Pb, acceptabelt för Zn och Ni, men dåligt för Cu. Utöver detta har en begränsad studie genomförts av förändringen av Pb kolloidala specier, järnhydroxider och organiskt kol, mellan uppströms och nedströms platser baserat på det nationella miljöövervakningsprogrammet ”Omdrevssjörna” (tidigare Riksinventeringen). Resultaten tyder på att förluster av organiskt material från markanvändning kan ha betydande påverkan på belastning av Pb. Fastläggning av organiskt bundet Pb i vattendragen var större än minerogent bundet Pb. Fortsatta studier av dessa observationer vid andra platser och med andra metaller rekommenderas starkt.Två dynamiska processbaserade metallretentionsmodeller, Lindström och Håkanson-modellen samt QWASI-modellen, har i denna studie framgångsrikt testats avseende metallerna Pb, Cd, Zn och Cu i tre sjöar. En massbalansmodell (FlowNorm) har också framgångsrikt testats i sex vattendrag. Det fanns bara ett fåtal nationellt tillgängliga sjödata enligt urvalet, med flera års övervakning av metallkoncentrationen i inflöde samt utflöde. Antalet sjöar med data kan utökas genom utökade urvalskriterier som föreslås i denna studie för fortsatt arbete med kalibrering och validering av modeller. Båda retentionsmodellerna Lindström och Håkanson samt QWASI gav jämförbara resultat, speciellt av koncentrationen i utflödet. Koncentrationen från sjöarna Innaren och Vidöstern beskrivs bra för alla metaller av båda modellerna. Båda modellerna har däremot beräknat koncentrationen i utflödet från sjön Södra Bergundasjön mycket högre än uppmätt medianhalt. Skillnaden beror troligtvis på överskattad bruttobelastning till Södra Bergundasjön. Testet visar nyttan av retentionsberäkningarna för att validera och korrigera bruttobelastning av metallerna. Lindström och Håkanson-modellen testades vidare i denna studie genom en känslighets- och en osäkerhetsanalys. Modellen var mest känslig för variationen i bruttobelastning. Nyttan av de dynamiska modellerna har vidare testats, som verktyg för att förutsäga effekten av eventuella förändringar av belastningen, vilket illustreras genom scenarioberäkningar i denna studie av Innaren och Vidöstern. Lindström och Håkanson-modellen kräver färre indata än QWASI och rekommenderas för fortsatt arbete.Enbart ett fåtal provplatser var lämpliga för retentionsmodellering med FlowNormprogrammet för vattendrag, och ännu färre data fanns tillgängligt för att beräkna den potentiella retentionen av metaller längs med vattendragen. För att kunna beräkna metallretentionen längs vattendragen på nationell nivå behövs ett annat urvalskriterie än de krav som ställts i denna studie. De platser som fanns tillgängliga för denna studie, visade dock att retention av metaller sker i vattendragen till olika grad. Fortsatt arbete bör därför beakta retention av metaller i både sjöar och vattendrag.Rekommendationer för fortsatt arbete:- Linjär regressionsmodell fungerar bäst för beräkning av den partikulära fraktionen av metaller och bör användas tillsvidare.- Ytterligare undersökningar av kolloidala och partikulära fraktioner, liknande den som genomförts för Pb i denna studie, rekommenderas för andra platser och metaller, vilket även innebär följande rekommendationer för att utöka underlagen: --Provtagning av sediment i de områden där den synoptiska provtagningen ägde rum.- Provtagning av filtrerade och ofiltrerade prover i de områden där den synoptiska provtagningen ägde rum.- Fortsatt arbete med retention av metaller rekommenderas starkt för att förbättra beräkningarna av bruttobelastningen av metallerna.- Öka antalet platser för kalibrering och validering genom föreslagna urvalskriterier.- Tillämpa Lindström och Håkanson-modellen på nationell nivå.
|
|
| 12. |
- Ejhed, Helene, et al.
(författare)
-
Nettobelastning av metaller i Dalälven
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Belastning och utsläpp av metaller till vatten rapporteras inom ett flertal internat-ionella rapporteringar; årligen till HELCOM och OSPAR samt vart tredje år till EEA WISE SoE Emissions. Cd, Pb, Hg och Ni ingår i listan av prioriterade ämnen enligt dotterdirektivet (2008/105/EG) till EUs ramdirektiv för vatten (2000/60/EG). För att analysera utsläpp och transport av metaller till inlandsvatten och havet måste källorna, men även avskiljning (retentionen) från källan till havet beräknas. En av de viktigaste indataparametrarna för att beräkna retention av metallerna är partikulär andel av metallerna i vatten.Syftet med detta projekt var att beräkna retention av metaller under transport från källan till havet i ett helt huvudavrinningsområde, Dalälven. Syftet var vidare att ta fram bättre regressionsekvationer som kan skatta andel partikulär metall med ytter-ligare styrande data utöver de kemiska parametrar som användes i tidigare studier och som kan ta hänsyn till förutsättningarna i Dalälvens avrinningsområde. Detta arbete bygger vidare på en tidigare testad retentionsmodell och framtagna regress-ionsekvationer för partikulär andel metaller (Lindström och Håkanson 2001, Ejhed m.fl.2011) och bruttobelastning (utsläpp vid källan) av metaller beräknat för avrin-ningsområden i hela Sverige (Ejhed m.fl., 2010). De metaller som hanterades i projektet var de prioriterade ämnena Cd, Hg, Pb och Ni, samt Cu och Zn som prio-riterades av Naturvårdsverket.För att förbättra regressionsekvationer för beräkning av andel partikulära metaller och anpassa till Dalälvens avrinningsområde utökades den befintliga miljööver-vakningen i Dalälven genom detta projekt med provtagning och analys av metaller i ofiltrerade prover både vid de redan befintliga provplatserna och vid ytterligare fem provplatser, i samråd med länsstyrelsen i Dalarna. Både flödesdata, andra ke-midata och markanvändning studerades för att bestämma vilka faktorer som styr andel metaller i partikulär form. Ekvationer togs fram för beräkning av andel me-taller i löst form för alla ovan nämnda metaller. Tillsammans med totalhalterna kan andel metaller i partikulär form skattas för alla metallerna i alla områden.Av analysen framgår att det finns stora skillnader för partikulär respektive löst andel för de olika metallerna och de olika områdena. Den största källan till variat-ion är dock pH. I sura vatten så som Lill-Fämtan är nästan alla metaller i löst form medan i mer alkaliska områden så som Dalälven Älvkarleby finns mycket större andel metaller i partikulär form. Vatten med större tillrinningsområden har oftast högre pH värden eftersom bidragen av välbuffrat grundvatten är större. Detta gäller också för sjöar med längre uppehållstider. Områden med stor andel åkermark och låg terräng uppvisar också högre andel metaller i partikulär form (Holen). Detta härrör förmodligen av mobilisering av större andel partiklar än i de andra vatten-dragen. Regressionerna som framtogs i denna rapport verka vara någorlunda uni-versella för alla studerade områden och påverkas inte av markanvändning eller om områdena är påverkade. Andel partikulära metaller varierar från 12% för Cu till 92% för Hg.En förenklad retentionsmodell utvecklades baserat på sjöarea, medeldjup, medel-tillrinning, partikulär andel metaller och fallhastighet för metallerna i Dalälvens avrinningsområde. Nettobelastningen och transport mellan delavrinningsområdena i Dalälven ner till havet beräknades genom att använda uppsättningen av HYPE-modellen baserat på Svenskt vattenarkiv 2010_2. Retentionsmodellens tillförlitlig-het testades genom att jämföra beräknad retention med motsvarande uppmätta värden i tre sjöar i Dalälvens avrinningsområde. Det konstaterades att den förenk-lade modellansatsen tämligen väl beskriver retentionen för de undersökta metaller-na. Den största avvikelsen noteras för Cu där den genomsnittliga retentionen un-derskattas med 16 procentenheter medan det för Zn och Pb skiljer 8 procentenheter mellan empiriskt och modellerat värde. Den sammanlagda retentionen för metal-lerna till havet varierar från 35% för Cu till 78% för Hg. Den inbördes skillnaden mellan olika metaller beror av deras varierande partikelbundna förekomst.Detta projekt har tagit fram en generell modell som med fördel skulle kunna appli-ceras och testas på andra avrinningsområden. Modellen kräver inte särskilt mycket indata, vilket kan anses vara en fördel då mycket indata sällan finns att tillgå i hu-vuddelen av Sveriges avrinningsområden. Modellen ger beräknad nettobelastning av källor till metaller och transport genom avrinningsområden, vilket är aktuellt och efterfrågat för påverkansanalys enligt ramdirektivet för vatten.Modellresultaten visar att beräkningar av retention och nettobelastning är ett nyttigt verktyg för att verifiera resultat av bruttobelastning och redovisning av källor till belastning. Det blev tydligt att det saknas källor i beräkningen av bruttobelastning-en i Dalälvens avrinningsområde. Det troliga är att läckage från gamla gruvdepo-nier saknas, men även att lokala variationer med högre läckage från diffusa källor kan orsaka skillnaden i uppmätt flodtransport och beräknad belastning.
|
|
| 13. |
- Erlandsson Lampa, Martin, et al.
(författare)
-
Catchment export of base cations : improved mineral dissolution kinetics influence the role of water transit time
- 2020
-
Ingår i: SOIL. - : Copernicus GmbH. - 2199-3971 .- 2199-398X. ; 6:1, s. 231-244
-
Tidskriftsartikel (refereegranskat)abstract
- Soil mineral weathering is one of the major sources of base cations (BC), which play a dual role in forest ecosystems: they function as plant nutrients and buffer against the acidification of catchment runoff. On a long-term basis, soil weathering rates determine the highest sustainable forest productivity that does not cause acidification. It is believed that the hydrologic residence time plays a key role in determining the weathering rates at the landscape scale. The PROFILE weathering model has been used for almost 30 years to calculate weathering rates in the rooting zone of forest soils. However, the mineral dissolution equations in PROFILE are not adapted for the saturated zone, and employing these equations at the catchment scale results in a significant overprediction of base cation release rates to surface waters. In this study, we use a revised set of PROFILE equations which, among other features, include retardation due to silica concentrations. Relationships between the water transit time (WTT) and soil water concentrations were derived for each base cation, by simulating the soil water chemistry along a one-dimensional flow path, using the mineralogy from a glacial till soil. We show how the revised PROFILE equations are able to reproduce patterns in BC and silica concentrations as well as BC ratios (Ca2+/BC, Mg2+/BC and Na+/BC) that are observed in the soil water profiles and catchment runoff. In contrast to the original set of PROFILE equations, the revised set of equations could reproduce the fact that increasing WTT led to a decreasing Na+/BC ratio and increasing Ca2+/BC and Mg2+/BC ratios. Furthermore, the total release of base cations from a hillslope was calculated using a mixing model, where water with different WTTs was mixed according to an externally modeled WTT distribution. The revised set of equations gave a 50% lower base cation release (0.23 eqm 2 yr 1) than the original PROFILE equations and are in better agreement with mass balance calculations of weathering rates. Thus, the results from this study demonstrate that the revised mineral dissolution equations for PROFILE are a major step forward in modeling weathering rates at the catchment scale.
|
|
| 14. |
- Erlandsson, Martin, et al.
(författare)
-
Direct and indirect effects of increasing dissolved organic carbon levels on pH in lakes recovering from acidification
- 2010
-
Ingår i: Journal of Geophysical Research: Biogeosciences. - 2169-8953 .- 2169-8961. ; 115:G3, s. G03004-
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we examine the impact of increasing concentrations of dissolved organic carbon (DOC) on the recovery from acidification for 66 lakes in Southern Sweden. The lakes are small, weakly buffered, and have all been affected by acidifying deposition. A majority of the lakes (similar to 75%) showed an increase in DOC concentrations between 1990 and 2008. The method used in this study was to model pH in 2008 from DOC, acid neutralizing capacity, pCO(2) (partial carbon dioxide pressure), and Al speciation, using both the DOC observed in 2008 and the "unelevated" DOC of 1990. Furthermore, we consider the indirect effects of increasing DOC on acidity, i.e., the ancillary effects from DOC on pCO(2), Al transport and speciation, and release of base cations (BCs). Our results indicate that the DOC increase in the latest decades has retarded the recovery from acidification by 0.13 pH units (median for all lakes) and by more than 1 unit for individual lakes. The effects of elevated pCO(2) and BC concentrations accompanying the DOC increase compensated for each other for the average lake, whereas the effects of higher Al transport on pH were minor. The estimate of the amount of BCs released with the organic anions is however uncertain, and further studies on this topic are needed.
|
|
| 15. |
- Erlandsson, Martin, et al.
(författare)
-
Increasing Dissolved Organic Carbon Redefines the Extent of Surface Water Acidification and Helps Resolve a Classic Controversy
- 2011
-
Ingår i: BioScience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 61:8, s. 614-618
-
Tidskriftsartikel (refereegranskat)abstract
- Concentrations of organic acids in freshwaters have increased significantly during recent decades across large parts of Europe and North America. Different theories of the causes (e.g., recovery from acidification, climate change, land use) have different implications for defining the preindustrial levels for dissolved organic carbon (DOC), which are crucial for assessing acidification and other aspects of water quality. We demonstrate this by classifying the acidification status of 66 lakes with long-term observations, representative of about 12,700 acid-sensitive lakes in nemoral and boreal Sweden. Of these lakes, 47% are classified as significantly acidified (Delta pH >= 0.4), assuming preindustrial DOC levels were equal to those observed in 1990. But if instead, the higher DOC levels observed in 2009 define preindustrial conditions, half as many lakes are acidified (24%). This emphasizes the need to establish reference levels for DOC and casts new light on the classic controversy about natural versus anthropogenic acidification.
|
|
| 16. |
- Erlandsson, M., et al.
(författare)
-
Spatial and temporal variations of base cation release from chemical weathering on a hillslope scale
- 2016
-
Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541 .- 1872-6836. ; 441, s. 1-13
-
Tidskriftsartikel (refereegranskat)abstract
- Cation release rates to catchment runoff from chemical weathering were assessed using an integrated catchment model that included the soil's unsaturated, saturated and riparian zones. In-situ mineral dissolution rates were calculated in these zones as a function of pH, aluminum and dissolved organic carbon (DOC) concentrations along a hillslope in Northern Sweden where soil water was monitored over nine years. Three independent sets of mineral dissolution equations of varying complexity were used: PROFILE, Transition-State Theory (TST), and the Palandri & Kharaka database. Normalization of the rate-coefficients was necessary to compare the equations, as published rate-coefficients gave base cation release rates differing by several orders of magnitude. After normalizing the TST- and Palandri & Kharaka-rate coefficients to match the base cation release rates calculated from the PROFILE-equations, calculated Ca2 + and Mg2 + release rates are consistent with mass balance calculations, whereas those of Na+ and K+ are overestimated. Our calculations further indicate that a significant proportion of base cations are released from the organic soils in the near-stream zone, in part due to its finer texture. Of the three sets of rate equations, the base cation release rates calculated from the normalized TST-equations were more variable than those calculated using the other two sets of equations, both spatially and temporally, due to its higher sensitivity to pH. In contrast, the normalized Palandri & Kharaka-equations were more sensitive to variations in soil temperature.
|
|
| 17. |
|
|
| 18. |
- Evans, Christopher, et al.
(författare)
-
The impact of wildfire on biogeochemical fluxes and water quality in boreal catchments
- 2021
-
Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 18, s. 3243-3261
-
Tidskriftsartikel (refereegranskat)abstract
- Wildfires are the major disturbance in boreal ecosystems and are of great importance for the biogeochemical cycles of carbon (C) and nutrients. However, these fire-induced impacts are hard to quantify and are rarely assessed together at an ecosystem level incorporating both aquatic and terrestrial environments. Following a wildfire in Sweden in an area with ongoing monitoring, we conducted a pre-fire (9 years) and post-fire (4 years) multi-catchment investigation of element losses (combustion and leaching) and impacts on water quality. Direct C and nitrogen (N) losses through combustion were ca. 4500 and 100 gm(-2), respectively. Net CO2 loss associated with soil and biomass respiration was similar to 150 g C m(-2) during the first year, but the ecosystem started to show net CO2 uptake in June 3 years post-fire. Aquatic C and N losses the first 12 months post-fire were 7 and 0.6 gm(-2), respectively. Hence, soil respiration comprised a non-negligible part of the post-fire C loss, whereas aquatic C losses were minor and did not increase post-fire. However, other elements (e.g. Ca, S) exhibited ecologically relevant increases in fluvial export and concentration with large peaks in the immediate post-fire period. The temporal dynamics of stream concentrations (Ca2+, Mg2+, K+,SO4-2, Cl-, NH4+, total organic N) suggest the presence of faster- and slower-release nutrient pools with half-lives of around 2 weeks and 4 months which we attribute to physicochemically and biologically mediated mobilization processes, respectively. Three years after the fire, it appears that dissolved fluxes of nutrients have largely returned to pre-fire conditions, but there is still net release of CO2.
|
|
| 19. |
- Fahad, Zaenab A., et al.
(författare)
-
Fractionation and assimilation of Mg isotopes by fungi is species dependent
- 2016
-
Ingår i: Environmental Microbiology Reports. - : Wiley. - 1758-2229. ; 8:6, s. 956-965
-
Tidskriftsartikel (refereegranskat)abstract
- Symbiotic ectomycorrhizal fungi mobilize nutrients from both organic and inorganic substrates and supply them to their host plants. Their role in mobilizing base cations and phosphorus from mineral substrates through weathering has received increasing attention in recent years but the processes involved remain to be elucidated. We grew selected ectomycorrhizal and nonmycorrhizal fungi in axenic systems containing mineral and organic substrates and examined their capacity to fractionate and assimilate stable isotopes of magnesium. The mycorrhizal fungi were significantly depleted in heavy isotopes with the lowest Mg-26 values (the difference between Mg-26 in fungal tissue and Mg-26 in the substrate) compared with nonmycorrhizal fungi, when grown on mineral substrates containing granite particles. The ectomycorrhizal fungi accumulated significantly higher concentrations of Mg, K and P than the nonmycorrhizal fungi. There was a highly significant statistical relationship between Mg-26 tissue signature and mycelial concentration of Mg, with a clear separation between most ectomycorrhizal fungi and the nonmycorrhizal fungi. These results are consistent with the idea that ectomycorrhizal fungi have evolved efficient mechanisms to mobilize, transport and store Mg within their mycelia.
|
|
| 20. |
- Finlay, Roger, et al.
(författare)
-
Reviews and syntheses : Biological weathering and its consequences at different spatial levels - from nanoscale to global scale
- 2020
-
Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 17:6, s. 1507-1533
-
Forskningsöversikt (refereegranskat)abstract
- Plant nutrients can be recycled through microbial decomposition of organic matter but replacement of base cations and phosphorus, lost through harvesting of biomass/biofuels or leaching, requires de novo supply of fresh nutrients released through weathering of soil parent material (minerals and rocks). Weathering involves physical and chemical processes that are modified by biological activity of plants, microorganisms and animals. This article reviews recent progress made in understanding biological processes contributing to weathering. A perspective of increasing spatial scale is adopted, examining the consequences of biological activity for weathering from nanoscale interactions, through in vitro and in planta microcosm and meso-cosm studies, to field experiments, and finally ecosystem and global level effects. The topics discussed include the physical alteration of minerals and mineral surfaces; the composition, amounts, chemical properties, and effects of plant and microbial secretions; and the role of carbon flow (including stabilisation and sequestration of C in organic and inorganic forms). Although the predominant focus is on the effects of fungi in forest ecosystems, the properties of biofilms, including bacterial interactions, are also discussed. The implications of these biological processes for modelling are discussed, and we attempt to identify some key questions and knowledge gaps, as well as experimental approaches and areas of research in which future studies are likely to yield useful results. A particular focus of this article is to improve the representation of the ways in which biological processes complement physical and chemical processes that mobilise mineral elements, making them available for plant uptake. This is necessary to produce better estimates of weathering that are required for sustainable management of forests in a post-fossil-fuel economy. While there are abundant examples of nanometre- and micrometre-scale physical interactions between microorganisms and different minerals, opinion appears to be divided with respect to the quantitative significance of these observations for overall weathering. Numerous in vitro experiments and microcosm studies involving plants and their associated microorganisms suggest that the allocation of plant-derived carbon, mineral dissolution and plant nutrient status are tightly coupled, but there is still disagreement about the extent to which these processes contribute to field-scale observations. Apart from providing dynamically responsive pathways for the allocation of plant-derived carbon to power dissolution of minerals, mycorrhizal mycelia provide conduits for the long-distance trans-portation of weathering products back to plants that are also quantitatively significant sinks for released nutrients. These mycelial pathways bridge heterogeneous substrates, reducing the influence of local variation in C : N ratios. The production of polysaccharide matrices by biofilms of interacting bacteria and/or fungi at interfaces with mineral surfaces and roots influences patterns of production of antibiotics and quorum sensing molecules, with concomitant effects on microbial community structure, and the qualitative and quantitative composition of mineral-solubilising compounds and weathering products. Patterns of carbon allocation and nutrient mobilisation from both organic and inorganic substrates have been studied at larger spatial and temporal scales, including both ecosystem and global levels, and there is a generally wider degree of acceptance of the systemic effects of microorganisms on patterns of nutrient mobilisation. Theories about the evolutionary development of weathering processes have been advanced but there is still a lack of information connecting processes at different spatial scales. Detailed studies of the liquid chemistry of local weathering sites at the micrometre scale, together with upscaling to soil-scale dissolution rates, are advocated, as well as new approaches involving stable isotopes.
|
|
| 21. |
- Franke, Vera, et al.
(författare)
-
Removal of per- and polyfluoroalkyl substances (PFASs) in a full-scale drinking water treatment plant: Long-term performance of granular activated carbon (GAC) and influence of flow-rate
- 2020
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 182
-
Tidskriftsartikel (refereegranskat)abstract
- Per- and polyfluoroalkyl substances (PFASs) have been ubiquitously detected in drinking water which poses a risk for human exposure. In this study, the treatment efficiency for the removal of 15 PFASs was examined in a full-scale drinking water treatment plant (DWTP) in the City of Uppsala, Sweden, over a period of two years (2015-2017). Removal of the five frequently detected PFASs was influenced by the total operation time of granular activated carbon (GAC) filters, GAC type and surface loading rate. The average removal efficiency of PFASs ranged from 92 to 100% for "young" GAC filters and decreased to 7.0 -100% for "old" GAC filters (up to 357 operation days, 29 300 bed volumes (BV) treated). Flow-rates were adjusted in two full-scale GAC filters of different operational age to examine the removal of PFAS and organic matter depending on GAC operational age and operating flow. The decrease in flow-rate by 10 L s(-1) from 39 to 29 L s(-1) led to an average increase of 14% and 6.5% in total PFAS removal efficiency for an "old" (264 operation days, 21 971 BV treated) and a "young" GAC filter (63 operation days, 5 725 BV treated), respectively. A cost-analysis for various operation scenarios illustrated the dominating effect of treatment goals and costs for GAC regeneration on overall GAC operation costs. The unit costs for GAC filters ranged from 0.08 to 0.10 (sic) M-3 water treated and 0.020-0.025 (sic) M-3 water treated for a treatment goal of 10 ng L-1 and 85 ng L-1, respectively, for Sigma(11)PFAS. Furthermore, it was concluded that prolonging the GAC service life by lowering the flow-rates after reaching the treatment goal could lead to a 26% cost-deduction. The results and methods presented in this study give drinking water providers valuable tools for the operation of a full-scale treatment train for the removal of PFAS in contaminated raw water. (C) 2020 The Authors. Published by Elsevier Ltd.
|
|
| 22. |
- Franke, Vera, et al.
(författare)
-
The Price of Really Clean Water: Combining Nanofiltration with Granular Activated Carbon and Anion Exchange Resins for the Removal of Per- And Polyfluoralkyl Substances (PFASs) in Drinking Water Production
- 2021
-
Ingår i: ACS ES&T water. - : American Chemical Society (ACS). - 2690-0637. ; 1, s. 782-795
-
Tidskriftsartikel (refereegranskat)abstract
- The removal of per- and polyfluoroalkyl substances (PFASs) presents a challenge for drinking water providers. Guidelines for PFAS concentrations in final drinking water are regularly updated to ever-decreasing values, and conventional drinking water treatment plants are not designed to remove PFASs. Currently, the most frequently used removal technique, adsorption to granular activated carbon (GAC), is often considered challenging. High-pressure membranes, such as nanofiltration (NF), have been shown to remove PFASs efficiently. However, the creation of a waste stream comprised of at least 10% of the feedwater volume is recognized as a major drawback of this technique. In this study, a NF pilot plant was operated at a drinking water treatment plant in the city of Uppsala, Sweden, for six months. NF removed up to >98% of PFASs and fulfilled other water quality targets, such as the removal of uranium-238, dissolved organic carbon (DOC), and mineral hardness from the raw water. The concentrate from the pilot plant was treated with two different GAC materials and two different anion exchange (AIX) resins in column tests, where the superior performance of AIX over GAC was observed in terms of PFAS removal. PFAS adsorption curves for GAC were found to superimpose each other for the two water types if normalized to the specific throughput of DOC. The application of the freely available PHREEQC model revealed improvement possibilities in terms of resin properties. A cost analysis using the column test results compared GAC filtration to the combination of NF with adsorption materials. Treatment costs were found to be largely dependent on the PFAS drinking water treatment goals and concentrate discharge requirements, which highlight the economic consequences of prevailing guidelines for drinking water and discharge to the environment. The results of this study provide both the scientific community as well as drinking water providers with important insights into the application of NF for PFAS removal during drinking water treatment as well as that mechanistic and economic aspects of NF treatment and the management of the resulting concentrate.
|
|
| 23. |
- Futter, Martyn, et al.
(författare)
-
Long-term trends in water chemistry of acid-sensitive Swedish lakes show slow recovery from historic acidification
- 2014
-
Ingår i: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 43, s. 77-90
-
Tidskriftsartikel (refereegranskat)abstract
- Long-term (1987-2012) water quality monitoring in 36 acid-sensitive Swedish lakes shows slow recovery from historic acidification. Overall, strong acid anion concentrations declined, primarily as a result of declines in sulfate. Chloride is now the dominant anion in many acid-sensitive lakes. Base cation concentrations have declined less rapidly than strong acid anion concentrations, leading to an increase in charge balance acid neutralizing capacity. In many lakes, modeled organic acidity is now approximately equal to inorganic acidity. The observed trends in water chemistry suggest lakes may not return to reference conditions. Despite declines in acid deposition, many of these lakes are still acidified. Base cation concentrations continue to decline and alkalinity shows only small increases. A changing climate may further delay recovery by increasing dissolved organic carbon concentrations and sea-salt episodes. More intensive forest harvesting may also hamper recovery by reducing the supply of soil base cations.
|
|
| 24. |
- Futter, Martyn, et al.
(författare)
-
Simulating dissolved organic carbon dynamics at the Swedish Integrated Monitoring sites with the Integrated Catchments Model for Carbon, INCA-C
- 2011
-
Ingår i: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40, s. 906-919
-
Tidskriftsartikel (refereegranskat)abstract
- Surface water concentrations of dissolved organic carbon ([DOC]) are changing throughout the northern hemisphere due to changes in climate, land use and acid deposition. However, the relative importance of these drivers is unclear. Here, we use the Integrated Catchments model for Carbon (INCA-C) to simulate long-term (1996-2008) streamwater [DOC] at the four Swedish integrated monitoring (IM) sites. These are unmanaged headwater catchments with old-growth forests and no major changes in land use. Daily, seasonal and long-term variations in streamwater [DOC] driven by runoff, seasonal temperature and atmospheric sulfate (SO4 2-) deposition were observed at all sites. Using INCA-C, it was possible to reproduce observed patterns of variability in streamwater [DOC] at the four IM sites. Runoff was found to be the main short-term control on [DOC]. Seasonal patterns in [DOC] were controlled primarily by soil temperature. Measured SO4 2- deposition explained some of the long-term [DOC] variability at all sites.
|
|
| 25. |
- Futter, Martyn, et al.
(författare)
-
Uncertainty in silicate mineral weathering rate estimates : source partitioning and policy implications
- 2012
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 7:2, s. 024025-
-
Tidskriftsartikel (refereegranskat)abstract
- Precise and accurate estimates of silicate mineral weathering rates are crucial when setting policy targets for long-term forest sustainability, critical load calculations and assessing consequences of proposed geo-engineering solutions to climate change. In this paper, we scrutinize 394 individual silicate mineral weathering estimates from 82 sites on three continents. We show that within-site differences of several hundred per cent arise when different methods are used to estimate weathering rates, mainly as a result of uncertainties related to input data rather than conceptually different views of the weathering process. While different methods tend to rank sites congruently from high to low weathering rates, large within-site differences in estimated weathering rate suggest that policies relying on quantitative estimates based upon a single method may have undesirable outcomes. We recommend the use of at least three independent estimates when making management decisions related to silicate mineral weathering rates.
|
|
