| 1. |
- Mayotte, Jean-Marc, et al.
(författare)
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The effects of ionic strength and organic matter on virus inactivation at low temperatures : general likelihood uncertainty estimation (GLUE) as an alternative to least-squares parameter optimization for the fitting of virus inactivation models
- 2017
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Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 25:4, s. 1063-1076
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Tidskriftsartikel (refereegranskat)abstract
- This study examined how the inactivation of bacteriophage MS2 in water was affected by ionic strength (IS) and dissolved organic carbon (DOC) using static batch inactivation experiments at 4 A degrees C conducted over a period of 2 months. Experimental conditions were characteristic of an operational managed aquifer recharge (MAR) scheme in Uppsala, Sweden. Experimental data were fit with constant and time-dependent inactivation models using two methods: (1) traditional linear and nonlinear least-squares techniques; and (2) a Monte-Carlo based parameter estimation technique called generalized likelihood uncertainty estimation (GLUE). The least-squares and GLUE methodologies gave very similar estimates of the model parameters and their uncertainty. This demonstrates that GLUE can be used as a viable alternative to traditional least-squares parameter estimation techniques for fitting of virus inactivation models. Results showed a slight increase in constant inactivation rates following an increase in the DOC concentrations, suggesting that the presence of organic carbon enhanced the inactivation of MS2. The experiment with a high IS and a low DOC was the only experiment which showed that MS2 inactivation may have been time-dependent. However, results from the GLUE methodology indicated that models of constant inactivation were able to describe all of the experiments. This suggested that inactivation time-series longer than 2 months were needed in order to provide concrete conclusions regarding the time-dependency of MS2 inactivation at 4 A degrees C under these experimental conditions.
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| 2. |
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| 3. |
- Pontér, Simon, et al.
(författare)
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Evaluation of a Multi-Isotope Approach as a Complement to Concentration Data within Environmental Forensics
- 2021
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Ingår i: Minerals. - : MDPI. - 2075-163X. ; 11:1
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Sutliff-Johansson, Stacy, et al.
(författare)
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Environmental Monitoring of Technology Critical Elements in contaminated Sediments in the Bothnian Bay, Northern Sweden
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Emerging technologies often are based on a variety of elements, some of which are in high demand for their importance in technological applications but are in relatively short supply. These technology critical elements (TCE) are often insufficiently researched and their natural abundance and behavior in environmental systems can be poorly understood or not known. The increase in demand of TCEs promotes a growth in their dissemination into the environment through anthropogenic means, and a lack of information on their natural abundances and behavior could have adverse effects on communities and natural habitats. This study investigated sediments affected by industrial activity in the Kallholm Bay and the open Bothnian Bay in Northern Sweden. Activities in the area include sulphide ore processing at the Rönnskär smelter as well as secondary scrap metal and end of life electronic recycling. The vertical distribution of TCEs (Ge, Te, Tl, Re, Ta, W, Ga, Nb and REE) were investigated in sediment cores collected in Kallholm Bay and the open Bothnian Bay. Determination of concentrations was achieved through Inductively Coupled Plasma–Sector Field Mass Spectrometry (ICP-SFMS). Fractionation of TCEs and REEs in the sediments was also investigated using a 5-step sequential extraction procedure. Evaluation of anthropogenically impacted sediments showed enrichment of all elements excluding Ga, Nb and the REEs, which are suspected to be of natural origin. Enrichment of Ge, Te, Tl, and Re were assumed to be related to sulphide ore processing whereas Ta and W were related to scrap metal and electronic processing. Several elements (Ge, Tl and Te) showed a change in geochemical behavior related to anthropogenic activity. Only Te showed an increase in the Bothnian Bay sediments related to anthropogenic activity.
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| 5. |
- Sutliff-Johansson, Stacy, et al.
(författare)
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Groundwater environmental forensic investigation combining multivariate statistical techniques and screening analyses
- 2020
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Ingår i: Environmental Forensics. - : Taylor & Francis. - 1527-5922 .- 1527-5930.
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Tidskriftsartikel (refereegranskat)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. The main objective of this study is to identify the sources of contamination, utilizing element screening analyses and multivariate statistical techniques. A second objective is to determine the usefulness of these techniques in Environmental Forensics investigations of contaminated groundwater at a complex industrial site. Water samples were collected from four groundwater monitoring wells and six waste deposit cells surrounding the contaminated area. Seventy-two elements are statistically examined and the dataset is reduced to the variables representative of the contaminated source material from the smelting process. A three-component model is identified and explains 88% of the total variation in the dataset. Component 1 includes concentrations of Cd, Co, Ni, Rb, Re, and Zn. This component displays a high correlation with two of the deposit cells and their associated groundwater monitoring wells. Component 2 is comprised of Sb, Cu, and Mo. This component displays a correlation between all monitoring wells and deposits likely due to the high mobility of these elements as oxyanions. Component 3 is dominated by As and displays high correlation to three older deposit cells representing a completely different source than for Components 1 and 2. The application of screening analyses and multivariate statistics in this study has achieved a meaningful identification of sources of contamination in the investigated area. It was also shown to be useful as an initial survey aiming to optimize a full-scale monitoring program at the site.
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| 6. |
- Sutliff-Johansson, Stacy, et al.
(författare)
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Tracing anthropogenic sources of Tantalum and Niobium in Bothnian Bay sediments, Sweden
- 2021
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Ingår i: Journal of Soils and Sediments. - : Springer. - 1439-0108 .- 1614-7480. ; 21:3, s. 1488-1503
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aims to evaluate temporal trends of Tantalum (Ta) and Niobium (Nb) concentrations in northern Baltic Sea sediments with focus on the potential impact from the Ronnskar sulfide ore smelter, located 15 km east of Skelleftea in northern Sweden. The potential of Ta or Nb to serve as tracers for environmental pollution caused by the electronic waste is compared. Lastly, correlations between Ta and Nb concentrations and those of major redox elements are investigated. Methods A 35-cm-deep core was collected in the harbor bay (Kallholmsfjarden) outside of the smelter. A secondary 6-m-deep sediment core was collected in the deep Bothnian Bay for comparative purposes. Element screening analysis was conducted the using ICP-SFMS for the Kallhomsfjarden core and a combination of ICP-SFMS and ICP-OES for the Bothnian Bay core. In the final analysis, a 5-step sequential extraction technique was preformed to allow for better prediction of the fate and mobility of Ta and Nb. Results and discussion In the vicinity of the smelter, Ta concentration increases from 0.42 to 3.8 ppm from the time coinciding with the beginning of electronic waste processing. Conversely, Nb concentration remained stable at background levels throughout the core at 6.33 +/- 0.78 ppm. The Nb/Ta ratio thus changed from 14.5 to 1.7, reflecting an increase of anthropogenic input of Ta into the bay sediments. In the pre-industrial part of the sediment, concentrations of both elements follow concentration of aluminosilicates in the core. In recent sediments, however, the anthropogenic Ta exhibits an association with hydrous ferric oxides (HFOs) and organic matter. Conclusions Notable increases in Ta concentrations began following the beginning of scrap metal and electronic waste processing at the Ronnskar smelter. Anthropogenic Ta introduced in the upper portion of the sediment and are more associated with HFOs and organic material than natural Ta seen in the deeper parts of the core where detrital Ta is most common. Niobium was not affected by the Ronnskar smelter and displayed no notable change to the preindustrial background.
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| 7. |
- Sutliff-Johansson, Stacy
(författare)
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Tracing anthropogenic Technology Critical Elements using Environmental Forensics : Case studies at Kallholmsfjärden and the Bothnian Bay, northern Sweden
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The rapidly changing landscape of today's technology industry has increased the number of electronic products being discarded. Society is always on the hunt for the latest product and newest technological advancement, thereby creating a constant influx of older model products into fast-growing waste streams. These products often contain a variety of metals, some of which are in high demand for their importance in technological applications but are in relatively short supply. These technology critical elements (TCE) are often insufficiently researched, and their natural abundance and behavior in environmental systems can be poorly understood or not known. This lack of comprehension creates a difficulty in tracing sources of their dissemination into the environment and an inadequacy in understanding the potential effects on environmental habitats. This thesis is an environmental forensics approach to tracing anthropogenically induced Cd and TCEs in sediments and groundwater in Kallholmsfjärdin, Northern Sweden. This area has been heavily industrialized since the early 1930s by Boliden Mineral AB's Cu-Pb-Zn smelter at Rönnskär. Process operations related to sulfide ore smelting, processing secondary scrap metals, and end-of-life electronics are all investigated. This thesis further attempts to identify anthropogenically induced changes to element mobility and influences on sediments in the Bothnian Bay's deeper basins.Paper-I was dedicated to tracing heavy metal contamination in groundwater monitoring wells around Rönnskär's waste deposit area. Sources of contamination were identified using multi-element screening analysis and multivariate statistical techniques such as principal component analysis and cluster analysis. Three sources of contamination were ultimately identified in the area. Principle component analysis was suggested to be a suitable method for the initial surveys prior to a full-scale monitoring program. However, to obtain more detailed information on specific element mobility and source identification, reactive-transport modeling and/or isotope analysis should be used.Paper-II explored the potential of Ta and Nb to serve as tracers for sediment contamination related to the processing of end-of-life electronics at Rönnskär. This paper further investigates changes in mobility related to anthropogenic activity and the possible transport into the Bothnian Bay. Two sediment cores were taken in Kallholm Bay and in the Bothnian Bays deeper basins. Sediments were analyzed using ICP-SFMS and ICP-OES. Identification of fractionated phases was analyzed through a 5-step sequential extraction procedure. The Nb/Ta ratio decreased from 14.5 to 1.7 due to an enrichment of Ta likely resulting from the processing of Ta-capacitor bearing electronics. An anthropogenic influence was also noticed in the partitioning of Ta with an increase in the hydrous ferric oxides (HFOs) and organic matter. This behavior was suggested to be a mechanism of the increase in the mobility of Ta into the Bothnian Bay. However, no increase in Bothnian Bay sediments was seen. Paper-III expanded on these results by investigating the remaining TCEs, including the REEs using the same sediments and methods. Several elements were found to increase in the sediments related to sulfide ore smelting (Ge, Te, Tl, and Re) and secondary scrap metal and end-of-life electronic processing (Ta and W). Gallium, Nb, and the REEs showed no influence from anthropogenic activity. Changes in mobility was observed due to anthropogenic influence for Ge, Tl, and Ta. Only Te showed an increase in the deeper Bothnian Bay sediments.
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