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  • 1.
    Abong'o, Deborah
    et al.
    University of Nairobi, Kenya.
    Wandiga, Shem
    University of Nairobi. Kenya.
    Jumba, Isac
    University of Nairobi, Kenya.
    van den Brink, Paul
    Wageningen University, the Netherlands.
    Nazariwo, Betty
    Makerere University, Uganda.
    Madadi, Vincent
    University of Nairobi, Kenya.
    Wafula, Godfrey
    University of Nairobi, Kenya.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Nkedi-Kizza, Peter
    University of Florida, USA.
    Organochlorine pesticide residue levels in soil from the Nyando River catchment, Kenya2015Inngår i: Africa Journal of Physical Sciences, ISSN 2313-3317, Vol. 2, nr 1, s. 18-32Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soil samples were collected from six locations representative of the Nyando River catchment area of the Lake Victoria over a period of two years. Sampling was done four times in the year in February, May, September and December 2005 and 2006 in farms where maize, tea, sugar cane, coffee, rice and vegetables have been grown over the years. This coincided with the effects of different seasons and farming activities on residue levels of the pesticides in use. The objective was to investigate levels and distribution of organochlorine pesticides that have either been banned or are restricted for use in Kenya. Organochlorine pesticides investigated were DDT, lindane, aldrin, dieldrin, heptachlor, endrin, endosulfan (both α- and β- isomers and endosulfan sulphate), the sum is called “total” or Σendosulfan and methoxychlor. Prior to the ban or restriction in use, these pesticides had found wide applications in public health for control of disease vectors and in agriculture for control of crop pests. The analysis revealed presence of all the targeted pesticides with the highest mean concentrations for methoxychlor 140 ± 1.5 μg/kg, Σendosulfan (30 ± 2.1 μg/kg), aldrin (18 ± 0.28 μg/kg), respectively. The results show the presence of these pesticides in soils in the basin and this could be impacting negatively on the ecosystem health of the area.

  • 2.
    Basapuram, Laxmi Gayatri Devi
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring.
    Lake Victoria - Carbon, Nitrogen, Phosphorus and Stable Isotope (δ13C) comparison between lake and catchment sediments2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Lake Victoria situated in East Africa faces an acute problem with eutrophication. Many reasons like agricultural production, industrialization, anthropogenic processes, the introduction of species, and economic activities have caused a stress to the overall well-being of the lake. Excess carbon, nitrogen, and phosphorus drive an increase in productivity which affects eutrophication. Previous studies on sediments and nutrient concentrations in the lake have concluded that nutrient concentrations increase due to release from the catchment. This study focuses on catchment sediments collected from four different sites and compares the results with sediments from two additional sites in the lake. The sediment core from Siaya indicates the highest concentrations of TOC (180 g/kg), TN (13 g/kg) and TP (17000μg/L). It is a rural site and poor agricultural practices such as the burn and slash, use of too many fertilizers, clearance of land, atmospheric deposition and precipitation increase elemental concentrations in the sediments compared to the more urban sites. In the lake sediments, the BILL core had higher concentrations of TP (430g/kg) and TN (16 g/kg) compared to the other site (LV-95) which is located far away from the margins of the lake. This core, however, had high TOC levels (180g/kg). The increase of nutrient levels in lake sediments is thought to be due to non-point sources from the catchment. Analyses of stable carbon isotope were used to infer the different organic matter source in the sediments. Based on the range of values for δ13C vs. C/N it is inferred that aquatic algal production and C4 vascular plants are the dominant sources for the organic matter input. The chemical characterization of catchment and lake sediments provides a qualitative link to nutrient influx and eutrophication in the lake.

  • 3.
    Bastviken, David
    et al.
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Svensson, Teresia
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Karlsson, Susanne
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Sandén, Per
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Öberg, Gunilla
    IRES, UBC, Canada.
    Temperature sensitivity indicates enzyme controlled chlorination of soil organic matter2009Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, nr 10, s. 3569-3573Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Old assumptions that chloride is inert and that most chlorinated organic matter in soils is anthropogenic have been challenged by findings of naturally formed organochlorines. Such natural chlorination has been recognized for several decades, but there are still very few measurements of chlorination rates or estimates of the quantitative importance of terrestrial chlorine transformations. While much is known about the formation of specific compounds, bulk chlorination remains poorly understood in terms of mechanisms and effects of environmental factors. We quantified bulk chlorination rates in coniferous forest soil using 36Cl-chloride in tracer experiments at different temperatures and with and without molecular oxygen (O2). Chlorination was enhanced by the presence of O2 and had a temperature optimum at 20 °C. Minimum rates were found at high temperatures (50 °C) or under anoxic conditions. The results indicate (1) that most of the chlorination between 4 and 40 °C was biotic and driven by O2 dependent enzymes, and (2) that there is also slower background chlorination occurring under anoxic conditions at 20 °C and under oxic conditions at 50 °C. Hence, while oxic and biotic chlorination clearly dominated, chlorination by other processes including possible abiotic reactions was also detected.

  • 4.
    Bastviken, David
    et al.
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Svensson, Teresia
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Sandén, Per
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Chlorine cycling and fates of 36Cl in terrestrial environments2013Rapport (Annet vitenskapelig)
    Abstract [en]

    Chlorine-36 (36Cl), a radioisotope of chlorine (Cl) with a half-life of 301,000 years, is present in some types of nuclear waste and is disposed in repositories for radioactive waste. As the release of 36Cl from such repositories to the near surface environment has to be taken into account it is of interest to predict possible fates of 36Cl under various conditions as a part of the safety assessments of repositories for radioactive waste. This report aims to summarize the state of the art knowledge on Cl cycling in terrestrial environments. The view on Cl cycling in terrestrial environments is changing due to recent research and it is clear that the chloride ion (Cl) is more reactive than previously believed. We group the major findings in three categories below according to the amount of data in support of the findings.

    From the result presented in this report it is evident that:

    • There is an ubiquitous and extensive natural chlorination of organic matter in terrestrial ecosystems.
    • The abundance of naturally formed chlorinated organic compounds (Clorg) frequently exceeds the abundance of Cl, particularly in soils. Thereby Clorg in many cases dominates the total Cl pool.
    • This has important implications for Cl transport. When reaching surface soils Cl will not be a suitable tracer of water and will instead enter other Cl pools (Clorg and biomass) that prolong residence times in the system.
    • Cl dominates import and export from terrestrial ecosystems while Clorg and biomass Cl can dominate the standing stock Cl within terrestrial ecosystems.
    • Both Cl and Clorg pools have to be considered separately in future monitoring programs addressing Cl cycling.

    Further, there are also indications (in need of confirmation by additional studies) that:

    • There is a rapid and large uptake of Cl by organisms and an accumulation in green plant parts. A surprisingly large proportion of total catchment Cl (up to 60%) can be found in the terrestrial biomass.
    • Emissions of total volatile organohalogens could be a significant export pathway of Cl from the systems.
    • Some of the Clorg may be very persistent and resist degradation better than average organic matter. This may lead to selective preservation of some Clorg (with associated low bioavailability).
    • There is a production of Clorg in tissues of e.g. plants and animals and Cl can accumulate as
    • chlorinated fatty acids in organisms.

    Most other nevertheless important aspects are largely unknown due to lack of data. Key unknowns include:

    • The development over time of major Cl pools and fluxes. As long as such data is lacking we cannot assess net changes over time.
    • How the precesses behind chlorination, dechlorination and transport patterns in terrestrial systems are regulated and affected by environmental factors.
    • The ecological roles of the chlorine cycling in general.
    • The ecological role of the microbial chlorination in particular.
    • The chlorine cycling in aquatic environments – including Cl and Clorg pools in sediment and water, are largely missing.

    Given the limited present information available, and particularly the lack of data with a temporal dimension and the lack of process understanding, predictive models are challenging. We also summarize currently available methods to study Cl in the environment.

  • 5.
    Belonoshko, Anatoly B.
    et al.
    Royal Institute Technology KTH, Sweden.
    Lukinov, Timofei
    Royal Institute Technology KTH, Sweden.
    Fu, Jie
    Royal Institute Technology KTH, Sweden; Dalian University of Technology, Peoples R China.
    Zhao, Jijun
    Dalian University of Technology, Peoples R China.
    Davis, Sergio
    Chilean Comm Nucl Energy CCHEN, Chile.
    Simak, Sergey
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Stabilization of body-centred cubic iron under inner-core conditions2017Inngår i: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 10, nr 4, s. 312-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Earths solid core is mostly composed of iron. However, despite being central to our understanding of core properties, the stable phase of iron under inner-core conditions remains uncertain. The two leading candidates are hexagonal close-packed and body-centred cubic (bcc) crystal structures, but the dynamic and thermodynamic stability of bcc iron under inner-core conditions has been challenged. Here we demonstrate the stability of the bcc phase of iron under conditions consistent with the centre of the core using ab initio molecular dynamics simulations. We find that the bcc phase is stabilized at high temperatures by a diffusion mechanism that arises due to the dynamical instability of the phase at lower temperatures. On the basis of our simulations, we reinterpret experimental data as support for the stability of bcc iron under inner-core conditions. We suggest that the diffusion of iron atoms in solid state may explain both the anisotropy and the low shear modulus of the inner core.

  • 6.
    Bidleman, Terry
    et al.
    Department of Chemistry, Umeå University, Umeå, Sweden.
    Andersson, Agneta
    Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden, Umeå Marine Sciences Centre, Hörnefors, Sweden.
    Jantunen, Liisa
    Centre for Atmospheric Research Experiments, Environment and Climate Change Canada, Canada.
    Kucklick, John
    Chemical Sciences Division, National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, SC, USA.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Research Unit: Environmental Sciences and Management, North–West University, Potchefstroom, South Africa.
    Letcher, Robert
    Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Canada.
    Tysklind, Mats
    Department of Chemistry, Umeå University, Umeå, Sweden.
    Wong, Fiona
    Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, Canada.
    A review of halogenated natural products in Arctic, Subarctic and Nordic ecosystems2019Inngår i: Emerging Contaminants, ISSN 2405-6650, E-ISSN 2405-6642, Vol. 5, s. 89-115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Halogenated natural products (HNPs) are organic compounds containing bromine, chlorine, iodine, andrarely fluorine. HNPs comprise many classes of compounds, ranging in complexity from halocarbons tohigher molecular weight compounds, which often contain oxygen and/or nitrogen atoms in addition tohalogens. Many HNPs are biosynthesized by marine bacteria, macroalgae, phytoplankton, tunicates,corals, worms, sponges and other invertebrates. This paper reviews HNPs in Arctic, Subarctic and Nordicecosystems and is based on sections of Chapter 2.16 in the Arctic Monitoring and Assessment Program(AMAP) assessment Chemicals of Emerging Arctic Concern (AMAP, 2017) which deal with the highermolecular weight HNPs. Material is updated and expanded to include more Nordic examples. Much ofthe chapter is devoted to “bromophenolic” HNPs, viz bromophenols (BPs) and transformation productsbromoanisoles (BAs), hydroxylated and methoxylated bromodiphenyl ethers (OH-BDEs, MeO-BDEs) andpolybrominated dibenzo-p-dioxins (PBDDs), since these HNPs are most frequently reported. Othersdiscussed are 2,20-dimethoxy-3,30,5,50-tetrabromobiphenyl (2,20-dimethoxy-BB80), polyhalogenated 10-methyl-1,20-bipyrroles (PMBPs), polyhalogenated 1,10-dimethyl-2,20-bipyrroles (PDBPs), polyhalogenatedN-methylpyrroles (PMPs), polyhalogenated N-methylindoles (PMIs), bromoheptyl- and bromooctylpyrroles, (1R,2S,4R,5R,10E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(20-chloroethenyl)-5-methylcyclohexane (mixed halogenated compound MHC-1), polybrominated hexahydroxanthene derivatives(PBHDs) and polyhalogenated carbazoles (PHCs). Aspects of HNPs covered are physicochemicalproperties, sources and production, transformation processes, concentrations and trends in the physicalenvironment and biota (marine and freshwater). Toxic properties of some HNPs and a discussion of howclimate change might affect HNPs production and distribution are also included. The review concludeswith a summary of research needs to better understand the role of HNPs as “chemicals of emergingArctic concern”.

  • 7.
    Bidleman, Terry
    et al.
    Umeå University, Sweden.
    Kurt-Karakus, Perihan
    Bahcesehir University, Istanbul, Turkey.
    Armitage, James
    University of Toronto, Ontario, Canada.
    Brown, Tanya
    University of Victoria, British Columbia, Canada.
    Danon Schaffer, Monica
    University of British Columbia, Vancouver, Canada.
    Helm, Paul
    Ontario Ministry of the Environment, Toronto, Canada.
    Hung, Haley
    Meteorological Services Canada .
    Jantunen, Liisa
    Environment Canada.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Li, Yi-Fan
    Environment, Canada.
    Loock, Daniela
    Royal Military College of Canada.
    Luttmer, Carol
    Royal Military College of Canada.
    Ma, Jianmin
    Lanzhou University, Peoples Republic of China.
    Macdonald, Robie
    Fisheries and Oceans, Canada.
    Mackay, Don
    Trent University, Peterborough, Ontario, Canada.
    Reid, Liisa
    Trent University, Peterborough, Ontario, Canada.
    Reimer, Ken
    Royal Military College of Canada.
    Chapter 2: Properties, sources, global fate and transport2013Inngår i: Canadian Arctic Contaminants Assessment Report III 2013: Persistent Organic Pollutants in Canada’ s North / [ed] Derek Muir, Perihan Kurt-Karakus and Peter Stow, Ottawa: Northern Contaminants Program, Aboriginal Affairs and Northern Development Canada , 2013, s. 19-146Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Part II of the second Canadian Arctic Contaminants Assessment Report (CACAR-II) began with a section on “Physicochemical Properties of Persistent Organic Pollutants”, which identified key physicochemical (pchem) properties, provided the rationale for their measurement or prediction and tabulated literature citations for chemicals that are of concern to the NCP (Bidleman et al. 2003). The section also discussed temperature dependence of pchem properties and their applications to describing partitioning in the physical environment.

    There is, and will continue to be, emphasis on predictive approaches to screening chemicals for persistence, bioaccumulation and toxic (PB&T)properties, as well as long-range atmospheric transport (LRAT) potential (Brown and Wania 2008, Czub et al. 2008, Fenner et al. 2005, Gouin andWania 2007, Howard and Muir 2010, Klasmeier et al. 2006, Matthies et al. 2009, Muir and Howard 2006). This has created the need for determining pchem properties of new and emerging chemicals of concern.

    Predicting gas exchange cycles of legacy persistent organic pollutants (POPs) and new and emerging chemicals of concern places a high demand on the accuracy of pchem properties, particularly the air/water partition coefficient, KAW. Hexachlorocyclohexanes (HCHs) in Arctic Ocean surface waters are close to air-water equilibrium, with excursions toward net volatilization or deposition that vary with location and season (Hargrave et al. 1993, Jantunen et al. 2008a, Lohmann et al. 2009, Su et al. 2006, Wong et al. 2011) while hexachlorobenzene (HCB) (Lohmann et al. 2009, Su et al. 2006, Wong et al. 2011) and some current use pesticides (CUPs) (Wong et al. 2011) are undergoing net deposition. The predicted Arctic Contamination Potential (ACP) for persistent organic chemicals is strongly influenced by ice cover due to its effect on air-water gas exchange (Meyer and Wania 2007).

    Many advances have taken place and numerous papers have been published since CACAR-II, which present new measurements and predictions of pchem properties. This section does not attempt to provide a comprehensive review of the field, or to compile pchem properties from the many studies. The approach taken is to highlight the reports which are most relevant to polar science, particularly in areas of improving reliability of pchem properties for POPs, improving experimental techniques and comparing predictive methods. The section ends with a discussion of polyparameter linear free energy relationships (pp-LFERs), which goes beyond partitioning descriptions based on single pchem properties by taking into account specific chemical interactions that can take place in airsurface and water-surface exchange processes. A detailed list of chemical names and nomenclature are provided in the Glossary.

  • 8.
    Conrad, Ralf
    et al.
    Max Planck Inst Terr Microbiol, Germany.
    Klose, Melanie
    Max Planck Inst Terr Microbiol, Germany.
    Enrich Prast, Alex
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Univ Fed Rio de Janeiro, Brazil.
    Acetate turnover and methanogenic pathways in Amazonian lake sediments2020Inngår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 17, nr 4, s. 1063-1069Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lake sediments in Amazonia are a significant source of CH4, a potential greenhouse gas. Previous studies of sediments using C-13 analysis found that the contribution of hydrogenotrophic versus acetoclastic methanogenesis to CH4 production was relatively high. Here, we determined the methanogenic pathway in the same sediments (n = 6) by applying (14)Cbicarbonate or 2-(14)Cacetate and confirmed the high relative contribution (50 %-80 %) of hydrogenotrophic methanogenesis. The respiratory index (RI) of 2-(14)Cacetate, which is (CO2)-C-14 relative to (CH4)-C-14 +(CO2)-C-14, divided the sediments into two categories, i.e., those with an RI amp;lt; 0.2 consistent with the operation of acetoclastic methanogenesis and those with an RI amp;gt; 0.4 showing that a large percentage of the acetate-methyl was oxidized to CO2 rather than reduced to CH4. Hence, part of the acetate was probably converted to CO2 plus H-2 via syntrophic oxidation, thus enhancing hydrogenotrophic methanogenesis. This happened despite the presence of potentially acetoclastic Methanosaetaceae in all the sediments. Alternatively, acetate may have been oxidized with a constituent of the sediment organic matter (humic acid) serving as oxidant. Indeed, apparent acetate turnover rates were larger than CH4 production rates except in those sediments with a Ramp;lt;0.2. Our study demonstrates that CH4 production in Amazonian lake sediments was not simply caused by a combination of hydrogenotrophic and acetoclastic methanogenesis but probably involved additional acetate turnover.

  • 9.
    Ghosh, Devanita
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Distribution and Biogeochemical Cycling of Arsenic In Grey and Brown Sand Aquifers in the Bengal Delta Plains (India)2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    An elevated level of Arsenic (As) in aquifers from India and Bangladesh affecting the human health has been widely reported since the late 1980s. The thesis aim is to investigate the present status of As contamination and biogeochemical cycling with direct role of diverse indigenous bacterial communities in As cycling in the Bengal Delta Plain (BDP) aquifers in Nadia district, West Bengal (India). The As(III) oxidizing bacterial communities were predominant in grey sand aquifers (GSA), but were characteristically absent in brown sand aquifers (BSA). Rainwater recharge containing inorganic and organic dissolved compounds played an important role in shaping the different groups of bacterial phenotypes. It included thearsenite-oxidizing bacteria as revealed by the aioA and 16S rRNA phylogeny. These bacterial communities in BDP groundwater were assumed to utilize the dissolved and sedimentary organic carbon (DOC and SOC) as the primary carbon source for respiration, and remobilization/immobilization of As involving reductive dissolution of iron oxyhydroxides. Hence, sediment and groundwater of these aquifer waters were characterized for their different inorganic constituents (metals) and organic compound classes. There were notable differences between the groundwater DOC and SOC pools. The only similarity between these carbon pools is presence of petroleum-derived hydrocarbons. The SOC in BSA has good correlation with the clay and silt-rich fraction. Notably, As formed complexes with iron, but not manganese. Biomarker characterization in sediments showed presence of terrigenous inputs along with petroleum-derived hydrocarbons. However, these hydrocarbons were absent in BSA sediments, and so were the arsenite oxidizing bacterial communities. Although DOC in groundwater plays an important role in sustaining the microorganisms, the contrasting character of SOC in BSA and GSA strongly influence the shaping of microbial community structure and biogeochemical cycling of As. This particularly affects the natural ‘safe’ drinking water capacity. Overall, the study gives a new directionfor long-term research on As biogeochemical cycling in the contaminated BDP aquifers.

    Delarbeid
    1. Arsenic Contamination in Soil and Sediment in India: Sources, Effects, and Remediation
    Åpne denne publikasjonen i ny fane eller vindu >>Arsenic Contamination in Soil and Sediment in India: Sources, Effects, and Remediation
    2015 (engelsk)Inngår i: Current Pollution Reports, ISSN 2198-6592, Vol. 1, nr 1, s. 35-46Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Arsenic contamination is turning out to be a major problem these days with its area coverage and the number of people affected directly or indirectly. Now, the level of the contaminant has spread over the soil and sediments from groundwater and other natural sources. Arsenic poisoning in groundwater events is familiar to the world, but the consequences of soil contamination are still unrevealed to the community, specially the people of contaminated counties. Arsenic is a serious instantaneous concern for the people and other life forms regarding the poisoning through crops and vegetables. Many remediation technologies that mainly include physical, chemical, and a few biological methods have been evolved with time to check its effects. The physical and chemical methods for this purpose are often inefficient and/or very expensive, mainly limited to application in aqueous systems, and produce toxic sludge, which again becomes a matter of concern. But bioremediation relies on the fact that biological organisms have the ability to degrade, detoxify, and even accumulate harmful chemicals and offers attractive perspectives for biomonitoring (via biosensors), treatment of wastewater, and the recycling of polluted soils.

    sted, utgiver, år, opplag, sider
    Springer, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-126596 (URN)10.1007/s40726-015-0004-2 (DOI)
    Tilgjengelig fra: 2016-03-31 Laget: 2016-03-31 Sist oppdatert: 2018-03-23bibliografisk kontrollert
    2. Diversity of arsenite oxidizing bacterial communities in arsenic-rich deltaic aquifers in West Bengal, India
    Åpne denne publikasjonen i ny fane eller vindu >>Diversity of arsenite oxidizing bacterial communities in arsenic-rich deltaic aquifers in West Bengal, India
    2014 (engelsk)Inngår i: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 5, nr 602, s. 1-14Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    High arsenic (As) concentration in groundwater has affected human health, particularly in South-East Asia putting millions of people at risk. Biogeochemical cycling of As carried out by different bacterial groups are suggested to control the As fluxes in aquifers. A functional diversity approach in link with As precipitation was adopted to study bacterial community structures and their variation within the As contaminated Bengal Delta Plain (BDP) aquifers of India. Groundwater samples collected from two shallow aquifers in Karimpur II (West Bengal, India), during years 2010 and 2011, were investigated to trace the effects immediately after monsoon period (precipitation) on community structure and diversity of bacterial assemblages with a focus on arsenite oxidizing bacterial phyla for two successive years. The study focused on amplification, clone library generation and sequencing of the arsenite oxidase large sub-unit gene aioA and 16S rRNA marker, with respect to changes in elemental concentrations. New set of primers were designed to amplify the aioA gene as a phylogenetic marker to study taxonomically diverse arsenite oxidizing bacterial groups in these aquifers. The overall narrow distribution of bacterial communities based on aioA and 16S rRNA sequences observed was due to poor nutrient status and anoxic conditions in these As contaminated aquifers. Proteobacteria was the dominant phylum detected, within which Acidoyorax, Hydrogenophaga, Albidiferax, Bosea, and Polymorphum were the major arsenite oxidizing bacterial genera based on the number of clones sequenced. The structure of bacterial assemblages including those of arsenite oxidizing bacteria seems to have been affected by increase in major elemental concentrations (e.g., As, Fe, S, and Si) within two sampling sessions, which was supported by statistical analyses. One of the significant findings of this study is detection of novel lineages of 16S rRNA-like bacterial sequences indicating presence of indigenous bacterial communities BDP wells that can play important role in biogeochemical cycling of elements including As.

    sted, utgiver, år, opplag, sider
    Frontiers, 2014
    Emneord
    Arsenic; aquifer; arsenite oxidation; aioA gene; phylogeny
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-113200 (URN)10.3389/fmicb.2014.00602 (DOI)000345856200001 ()25484877 (PubMedID)
    Merknad

    Funding Agencies|Swedish Research Link-Asia Program; Department of Science and Technology (DST), Government of India; DST

    Tilgjengelig fra: 2015-01-13 Laget: 2015-01-12 Sist oppdatert: 2017-12-05
    3. Characterization and microbial utilization of dissolved lipid organic fraction in arsenic impacted aquifers (India)
    Åpne denne publikasjonen i ny fane eller vindu >>Characterization and microbial utilization of dissolved lipid organic fraction in arsenic impacted aquifers (India)
    2015 (engelsk)Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 527, s. 221-233Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The coupled role of organic matter (OM) and microbial activity is widely acknowledged in arsenic (As) biogeochemical cycling in sedimentary environments. However, little is known about OM characteristics particularly the dissolved fraction in the Bengal Delta Plain aquifers – one of the worst As impacted regions in the world. Ongoing investigations in As-rich aquifers in Nadia district (West Bengal, India) indicate presence of arsenite As(III) oxidizing bacterial communities in the Grey Sand Aquifers (GSA), but absent in Brown Sand Aquifers (BSA). In this study, we investigate the key differences in dissolved organic carbon (DOC) characteristics and its relationship with differences in elemental concentrations, distribution of biomarkers, and utilization of DOC by in situ microbial communities in BSA and GSA. We demonstrate a new approach using ENVI™ C-18 DSK discs to pre-concentrate DOC from large volumes of water, and further extract the OM and separate it into different lipid fractions using the solid phase extraction technique. The aquifers show marked heterogeneity in terms of their DOC characteristics and elemental profiles irrespective of their grey or brown color. DOC indicates variable inputs of terrestrial derived OM sources, and OM derived from decomposition and/or microbial cellular components. DOC in the aquifers consist of predominantly n-alkanoic acids (∌80%) followed by n-alkanes and n-alcohols. The GSAs indicate high iron (Fe) and manganese (Mn) concentrations, and presence of mature petroleum derived hydrocarbons in DOC. BSA has comparatively lower concentrations of Fe and Mn, and shows absence of mature hydrocarbons in DOC. Experiments in presence of indigenous bacteria from groundwater with DOC lipid extracts as the sole carbon source indicate higher growth in the GSA samples implying preferential use of DOC. The potential availability of DOC in these aquifers can influence the community composition of indigenous heterotrophic microbial flora, which in turn can affect elemental cycles including that of As.

    Emneord
    Arsenic, Aquifers, DOC, Microbes, Aquatic biomarkers
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-126597 (URN)10.1016/j.jhydrol.2015.04.051 (DOI)000358629100021 ()
    Tilgjengelig fra: 2016-03-31 Laget: 2016-03-31 Sist oppdatert: 2018-03-19bibliografisk kontrollert
    4. Elemental and biomarker characteristics in a Pleistocene aquifer vulnerable to arsenic contamination in the Bengal Delta Plain, India
    Åpne denne publikasjonen i ny fane eller vindu >>Elemental and biomarker characteristics in a Pleistocene aquifer vulnerable to arsenic contamination in the Bengal Delta Plain, India
    2015 (engelsk)Inngår i: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 61, s. 87-98Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    An elevated level of arsenic (As) in the Indo-Gangetic delta plain aquifers has been reported since the 1990s. Organic matter (OM) present in groundwater and aquifer sediments supports the microbial communities in these aquifers. During installation of a drinking water well, 26 sediment intervals of 6 m each were retrieved up till 156 m from a Pleistocene brown sand aquifer (BSA). Grain size distribution, sequential extraction of metals and total extractable lipids were analyzed in each sample. These parameters were statistically correlated in order to establish relationship between the physical vs. inorganic and organic characteristics, and how these properties affected the distribution of As in BSAs. The aquifer sediments consisted of medium to coarse sand except the surface sediments and those at the bottom of the well, which had high clay and slit content. Arsenic (As) concentration in sediments ranged from 2 to 21 mg/kg and indicated a strong correlation with grain size. Arsenic was mostly associated with crystalline oxides and silicate-rich minerals. Arsenic showed significant correlation with Fe in all fractions, and suggests presence of pyrite bound As-bearing minerals in these sediments. The diagnostic sedimentary lipid biomarkers indicated presence of compounds derived from vascular plants and microbial cell wall. This inference was supported by various diagnostic lipid ratios. The biomarkers were abundant in surface and deeper layers, which had high clay and silt content. The BSA sediments indicated preferential preservation of n-alkanes over other functional compounds, which were more reactive and subject to degradation. The thick clay layer at 132-156 m contained visible plant fragments, and OM in this layer indicated preferential preservation of organic carbon most likely due to the absence of specific microbial communities that degraded these compounds and mobilized As. Statistical analyses indicated the influence of selective inorganic and organic components (As, Fe and fatty acids) controlling the co-distribution of various inorganic and organic components in the aquifer.

    sted, utgiver, år, opplag, sider
    PERGAMON-ELSEVIER SCIENCE LTD, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-122048 (URN)10.1016/j.apgeochem.2015.05.007 (DOI)000360654200008 ()
    Merknad

    Funding Agencies|Department of Science and Technology, Government of India; Swedish Research Link-Asia Program [2009-6470]; Linkoping University, Sweden

    Tilgjengelig fra: 2015-12-18 Laget: 2015-10-19 Sist oppdatert: 2017-12-01
  • 10.
    Ghosh, Devanita
    et al.
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Laboratory of Integrative Taxonomy and Molecular Ecology, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
    Routh, Joyanto
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Bhadury, Punyasloke
    Laboratory of Integrative Taxonomy and Molecular Ecology, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
    Characterization and microbial utilization of dissolved lipid organic fraction in arsenic impacted aquifers (India)2015Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 527, s. 221-233Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The coupled role of organic matter (OM) and microbial activity is widely acknowledged in arsenic (As) biogeochemical cycling in sedimentary environments. However, little is known about OM characteristics particularly the dissolved fraction in the Bengal Delta Plain aquifers – one of the worst As impacted regions in the world. Ongoing investigations in As-rich aquifers in Nadia district (West Bengal, India) indicate presence of arsenite As(III) oxidizing bacterial communities in the Grey Sand Aquifers (GSA), but absent in Brown Sand Aquifers (BSA). In this study, we investigate the key differences in dissolved organic carbon (DOC) characteristics and its relationship with differences in elemental concentrations, distribution of biomarkers, and utilization of DOC by in situ microbial communities in BSA and GSA. We demonstrate a new approach using ENVI™ C-18 DSK discs to pre-concentrate DOC from large volumes of water, and further extract the OM and separate it into different lipid fractions using the solid phase extraction technique. The aquifers show marked heterogeneity in terms of their DOC characteristics and elemental profiles irrespective of their grey or brown color. DOC indicates variable inputs of terrestrial derived OM sources, and OM derived from decomposition and/or microbial cellular components. DOC in the aquifers consist of predominantly n-alkanoic acids (∌80%) followed by n-alkanes and n-alcohols. The GSAs indicate high iron (Fe) and manganese (Mn) concentrations, and presence of mature petroleum derived hydrocarbons in DOC. BSA has comparatively lower concentrations of Fe and Mn, and shows absence of mature hydrocarbons in DOC. Experiments in presence of indigenous bacteria from groundwater with DOC lipid extracts as the sole carbon source indicate higher growth in the GSA samples implying preferential use of DOC. The potential availability of DOC in these aquifers can influence the community composition of indigenous heterotrophic microbial flora, which in turn can affect elemental cycles including that of As.

  • 11.
    Gonsior, Michael
    et al.
    University of Maryland, MD 20688 USA.
    Valle, Juliana
    University of Federal Rio de Janeiro, Brazil; Helmholtz Zentrum Munchen, Germany.
    Schmitt-Kopplin, Philippe
    Helmholtz Zentrum Munchen, Germany; Technical University of Munich, Germany.
    Hertkorn, Norbert
    Helmholtz Zentrum Munchen, Germany.
    Bastviken, David
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Luek, Jenna
    University of Maryland, MD 20688 USA.
    Harir, Mourad
    Helmholtz Zentrum Munchen, Germany.
    Bastos, Wanderley
    University of Federal Rondonia, Brazil.
    Enrich Prast, Alex
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. University of Federal Rio de Janeiro, Brazil.
    Chemodiversity of dissolved organic matter in the Amazon Basin2016Inngår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, nr 14, s. 4279-4290Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Regions in the Amazon Basin have been associated with specific biogeochemical processes, but a detailed chemical classification of the abundant and ubiquitous dissolved organic matter (DOM), beyond specific indicator compounds and bulk measurements, has not yet been established. We sampled water from different locations in the Negro, Madeira/Jamari and Tapajos River areas to characterize the molecular DOM composition and distribution. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with excitation emission matrix (EEM) fluorescence spectroscopy and parallel factor analysis (PARAFAC) revealed a large proportion of ubiquitous DOM but also unique area-specific molecular signatures. Unique to the DOM of the Rio Negro area was the large abundance of high molecular weight, diverse hydrogen-deficient and highly oxidized molecular ions deviating from known lignin or tannin compositions, indicating substantial oxidative processing of these ultimately plant-derived polyphenols indicative of these black waters. In contrast, unique signatures in the Madeira/Jamari area were defined by presumably labile sulfur-and nitrogen-containing molecules in this white water river system. Waters from the Tapajos main stem did not show any substantial unique molecular signatures relative to those present in the Rio Madeira and Rio Negro, which implied a lower organic molecular complexity in this clear water tributary, even after mixing with the main stem of the Amazon River. Beside ubiquitous DOM at average H / C and O / C elemental ratios, a distinct and significant unique DOM pool prevailed in the black, white and clear water areas that were also highly correlated with EEM-PARAFAC components and define the frameworks for primary production and other aspects of aquatic life.

  • 12.
    Gustavsson, Malin
    Linköpings universitet, Institutionen för tema, Tema vatten i natur och samhälle. Linköpings universitet, Filosofiska fakulteten.
    Chlorination of organic material in different soil types2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Research has shown that formation of chlorinated organic matter occurs naturally and that organic chlorine is as abundant as the chloride ion in organic soils. A large number of organisms are known to convert inorganic chloride (Clin) to organic chlorine (Clorg) (e.g. bacteria, lichen, fungi and algae) and some enzymes associated to these organisms are capable of chlorinating soil organic matter. The aim with the study was to compare organic matter chlorination rates in soils from several different locations dominated by either coniferous forest or pasture. Soil from eight samples sites in the southern of Sweden were incubated at 20°C with addition of 36Clin in a 138 days long radiotracer experiment. The results show that transformation of 36Clin to 36Clorg occurred and that the amounts of 36Clorg increased over time. The chlorination rate was higher in the samples from coniferous forest than in samples containing pasture soil, where the specific chlorination rate was 3-4 times smaller. This study contributes new information about chlorination in various soil types and soil from different locations in southern central Sweden. The similarity between the chlorination rates measured in coniferous forest soils so far indicate that up scaling to regional estimates may be less problematic than expected.

  • 13.
    Kylin, Henrik
    et al.
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Muir, Derek
    Environment Canada, Canada.
    Pentachlorophenol (PCP) and pentachloroanisole (PCA)2017Inngår i: AMAP Assessment 2016: Chemicals of Emerging Arctic Concern, Oslo: Arctic Monitoring and Assessment Programme (AMAP) , 2017, s. 205-211Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Pentachlorophenol (PCP) was first synthesized for use as a fungicide for wood protection in the 1930s. PCP affects most organisms by decoupling oxidative phosphorylation and other crucial biochemical functions (IPCS, 1987; UNEP, 2013e). As a result it has found a wide range of biocidal and pesticidal uses. Due to adverse environmental and health effects, restrictions  on the use of PCP were first imposed in the 1970s with total bans in effect in some countries by the 1980s (UNEP, 2013d). As of 2014, PCP was still in use in India, Canada and the USA (UNEP, 2014a). In May 2015, PCP was included in Annex A of the Stockholm Convention: calling for elimination, with a time-limited exemption for impregnation of utility poles and crossarms (UNEP, 2015a).

  • 14.
    Mendes, Lipe Renato Dantas
    et al.
    Aarhus Univ, Denmark.
    Tonderski, Karin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Kjaergaard, Charlotte
    Aarhus Univ, Denmark; SEGES, Denmark.
    Phosphorus accumulation and stability in sediments of surface-flow constructed wetlands2018Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 331, s. 109-120Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surface-flow constructed wetlands (CWs) are systems that replicate the nutrient reduction processes of natural wetlands and are considered suitable measures to reduce the nutrient losses from agricultural drainage discharge to surface waters. The present study aimed to investigate the biogeochemical stability of phosphorus (P) in three CWs. Intact soil cores were collected from each CW zone and included the soil and the sediment layer (average 28 mm thickness) formed by deposition of the incoming sediments with the water flow. Soil and sediment layer were analysed geochemically, including bulk density, pH, and total contents of carbon, nitrogen, P as well as different extracts of iron (Fe), aluminium and P. In situ measurements of soil redox potential, dissolved oxygen concentration and temperature were carried out in the CWs during 16 months. Grab water samples were collected across the CWs for determination of P species, total Fe, sulphate and pH. Soil core analysis revealed that the major P storage in the CWs was attributed to retention of Fe-bound P in the sediment layer. The Fe and total P (TP) retention differed significantly between CWs (11-63 g Fe m(-2) yr(-1) and 1-9 g TP m(-2) yr(-1)). Amorphous Fe oxides constituted the major P sorbent fraction in the soil and sediments of all CWs, and the higher P sorption capacity in the sediment layer demonstrated the continuous supply of P sorbents to this layer. The stability of Fe bound P in the anaerobic sediments seemed to be controlled by the high molar ratios of bicarbonate-dithionite extractable Fe (Fe-BD) to associated P, which varied from 21 to 49, and the presence of an aerobic sediment-water

  • 15.
    Routh, Joyanto
    et al.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Grossman, Ethan L.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Murphy, Ellyn M.
    Environmental and Energy Sciences Division, Battelle Pacific Northwest Laboratory, Richland, WA 99352, USA.
    Benner, Ronald
    Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
    Characterization and Origin of Dissolved Organic Carbon in Yegua Ground Water in Brazos County, Texas2005Inngår i: Groundwater, E-ISSN 1745-6584, Vol. 39, nr 5, s. 760-767Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract Dissolved organic carbon (DOC) concentrations in five shallow (< 20 m) and three deeper wells (27 to 30 m) in the Eocene Yegua Formation (Brazos County in east-central Texas) ranged from 92 to 500 ᅵm. Characterization of high, intermediate, and low molecular weight DOC fractions (HMW > 3000 amu, IMW 1000 to 3000 amu, and LMW 500 to 1000 amu) and combined neutral sugar analyses provide information on organic matter sources in the Yegua aquifers. Combined neutral sugars ranged in concentration from 0.6 to 2.7 ᅵmol/L and comprised 0.8% to 6.7% of DOC in ground water. Glucose was the most abundant neutral sugar, followed by xylose and galactose, arabinose, mannose, rhamnose, and fucose. These combined neutral sugars were more diagenetically altered in shallow, oxic ground water as indicated by high mole % fucose + rhamnose and low neutral sugar yield. The precursors for neutral sugars are most probably angiosperm leaves, which show a similar distribution pattern of neutral sugars. Ground water DOC was depleted in 13C relative to soil-zone organic matter (OM) (-16ᅵ to -19ᅵ). The d13C values of bulk DOC and HMW DOC ranged from -24ᅵ to ᅵ32ᅵ, whereas LMW and IMW DOC ranged from -32ᅵ to -34ᅵ and ᅵ16ᅵ to ᅵ28ᅵ, respectively. This variability in d13C values is probably related to microbial processes and selective preservation of OM. Carbon isotope analyses in bulk and different molecular weight DOC fractions imply a predominantly C3 OM source and a low contribution of soil-zone OM to DOC.

  • 16.
    Routh, Joyanto
    et al.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX, 77843, USA.
    Grossman, Ethan L.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX, 77843, USA.
    Ulrich, Glenn A.
    Institute for Energy and the Environment, Department of Botany and Microbiology, 770 Van Vleet Oval, University of Oklahoma, Norman, OK, 73019-0245, USA.
    Suflita, Joseph M.
    Institute for Energy and the Environment, Department of Botany and Microbiology, 770 Van Vleet Oval, University of Oklahoma, Norman, OK, 73019-0245, USA.
    Volatile organic acids and microbial processes in the Yegua formation, east-central Texas2001Inngår i: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 16, nr 2, s. 183-195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Geochemical and microbiological evidence indicates that viable microorganisms produce and consume volatile organic acids (VOA) in the Yegua formation. Acetic and propionic acid concentrations in mudstones range from 200 to 1270 and 20 to 38 nmol·gdw−1 respectively, whereas concentrations in sands are 50–200 and less than 20 nmol·gdw−1. VOA concentrations in sediments and in laboratory incubations suggest net production of VOAs by microorganisms in mudstones, and net consumption of VOAs by SO4 reducing bacteria (SRB) in sands. Notably, SRB activity is mostly confined to aquifer sands. Vertical diffusion and advection were modeled to estimate acetic acid transport from aquitard to aquifer. Assuming that SRB completely respire the acetic acid transported into the aquifer (3.2 μmol·l−1·m·a−1), the CO2 production rate in the aquifer sands is 5.3 μmol·l−1·a−1. This slow mineralization rate of in situ organic matter is within the range for deep aquifers, and probably accounts for the long-term survival of microorganisms in oligotrophic environments. Finally, the microbial communities in Yegua sediments appear to exhibit a loose commensalism, with microorganisms in aquitards providing VOAs for respiratory processes (i.e., SO4 reduction) in aquifers.

  • 17.
    Routh, Joyanto
    et al.
    Department of Earth Sciences, IISER-Kolkata, Mohanpur, India.
    Hjelmquist, Per
    Department of Geology and Geochemistry, Stockholm University, Stockholm, Sweden.
    Distribution of arsenic and its mobility in shallow aquifer sediments from Ambikanagar, West Bengal, India2011Inngår i: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 26, nr 4, s. 505-515Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sediments from a core retrieved during installation of a shallow drinking water well in Ambikanagar (West Bengal, India) were analyzed for various physical and chemical parameters. The geochemical analyses included: (1) a 4-step sequential extraction scheme to determine the distribution of As between different fractions, (2) As speciation (As(3+) vs. As(5+)), and (3) C, N and S isotopes. The sediments have a low percentage of organic C and N (0.10-0.56% and 0.01-0.05%, respectively). Arsenic concentration is between 2 and 7 mg kg(-1), and it is mainly associated with the residual fraction, less susceptible to chemical weathering. The proportion of As(3+) in these sediments is high and ranges from 24% to 74%. Arsenic in the second fraction (reducible) correlates well with Mn, and in the residual fraction As correlates well with several transition elements. The stable isotope results indicate microbial oxidation of organic matter involving SO(4) reduction. Oxidation of primary sulfide minerals and release of As from reduction of Fe(oxy)hydroxides do not seem important mechanisms in As mobilization. Instead, the dominance of As(3+) and presence of As(5+) reducing microorganisms in this shallow aquifer imply As remobilization involving microbial processes that needs further investigations.

  • 18.
    Routh, Joyanto
    et al.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Ikramuddin, Mohammed
    Department of Geology, Eastern Washington University, Cheney, WA 99004, USA.
    Trace-element geochemistry of Onion Creek near Van Stone lead-zinc mine (Washington, USA) — Chemical analysis and geochemical modeling1996Inngår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 133, nr 1, s. 211-224Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Van Stone lead-zinc mine in Washington is a possible contamination source of Columbia River water. Breaching of an old tailings pond, seepage of contaminated water, and surficial transport of mine tailings have increased trace-element (TE) concentrations in the Onion Creek water and sediments. Chemical analyses of water and sediment samples indicate high TE levels near the breached tailings pond. TE contamination indices for sediments indicate high values of Pb, Zn, and other TE’s which decrease downstream. High Kd values (> 104) for several TE’s (e.g., Al, Cd, Fe, Mn, Pb, V, and Zn) suggest their enrichment in the solid phase. TE concentrations in Onion Creek water and sediment sharply attenuate downstream due to: (1) enhanced carbonate dissolution, thereby increasing pH and immobilizing TE’s; (2) sorption to oxides; and (3) change in lithology from carbonate to granite. Speciation model MINTEQA2 was used to study the effect on TE dispersion due to dissolution-precipitation reactions and adsorption to ferrihydrite. In addition to the field and chemical data, the model also supports the hypothesis that Onion Creek sediments are the major sink for TE’s at VSM. Model runs indicate precipitation of Al, Ba, Ca, Fe, Mg, and Mn minerals from oversaturation, whereas TE’s with low concentrations (Cr, Cu, Ni, Se) or geochemically more mobile (As, Mo, Sb) remain dissolved in water. Near the tailings ponds, high pH and abundance of sorption sites in sediments contribute to the complete adsorption of Pb and Zn species. Because ambient conditions result in the sorption of most Pb and Zn ions, Onion Creek water quality meets EPA regulatory standards. These species will persist in Onion Creek sediments as sorbed or insoluble complexes, and without drastic pH changes (< 4.0) they will remain immobilized. However, continued TE enrichment in sediments will prove hazardous to filter feeding and aquatic organisms.

  • 19.
    Routh, Joyanto
    et al.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    McDonald, Thomas J.
    Department of Civil Engineering, Texas A&M University, College Station, TX 77843, USA.
    Grossman, Ethan L.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Sedimentary organic matter sources and depositional environment in the Yegua formation (Brazos County, Texas)1999Inngår i: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 30, nr 11, s. 1437-1453Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The complex depositional environment of the Eocene Yegua formation (Brazos County, Texas) can be better understood by integrating organic matter (OM) geochemistry with stratigraphy. Yegua sediments represent parasequences separated by exposure surfaces. Organic petrography and geochemistry (biomarkers, C/N ratios, and carbon isotopes) indicate the presence of both terrestrial and marine OM in transgressive sediments. In contrast, regressive sediments contain only terrestrial OM. These differences relate to contrasting OM sources and depositional styles on the shelf. OM in the sediments is immature and the potential for generating hydrocarbons is poor. The study suggests that organic geochemical data can help in distinguishing transgressive and regressive environments in sedimentary formations.

  • 20.
    Routh, Joyanto
    et al.
    Department of Geology and Geochemistry, Stockholm University, S 10691 Stockholm, Sweden.
    Meyers, Philip A.
    Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109-1063, USA.
    Gustafsson, Örjan
    Department of Geology and Geochemistry, Stockholm University, S 10691 Stockholm, Sweden.
    Baskaran, Mark
    Department of Geology, Wayne State University, Detroit, Michigan 48202, USA.
    Hallberg, Rolf
    Department of Geology and Geochemistry, Stockholm University, S 10691 Stockholm, Sweden.
    Schï¿œldstrï¿œm, Anna
    Department of Geology and Geochemistry, Stockholm University, S 10691 Stockholm, Sweden.
    Sedimentary geochemical record of humanï¿œinduced environmental changes in the Lake Brunnsviken watershed, Sweden2004Inngår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Limnology and Oceanography, Vol. 49, nr 5, s. 1560-1569Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Environmental changes in Lake Brunnsviken, its watershed, and the greater Stockholm region since the middle of the nineteenth century have left interpretable geochemical imprints in the bottom sediments. These human-induced perturbations within the lakeï¿œs watershed included agriculture, urbanization, sewage and industrial disposal, and water column aeration. Smaller d15Ntotal values, high organic carbon mass accumulation rates, low C:N ratios, and larger d13Corg values identify periods of increased nutrient delivery and elevated primary productivity in the lake. C: S ratios that change from high to low trace the transition from an oxic hypolimnion to an anoxic one during the periods of high productivity. Accumulations of redox-sensitive trace elements increase during the anoxic period and are further magnified during a time of industrial waste discharge into the lake. A recent decrease in black carbon concentrations in sediments reflects the conversion from wood and coal to cleaner forms of energy.

  • 21.
    Shrivastava, Anamika
    et al.
    Earth and Environmental Science Research Laboratory, Department of Earth Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal, India .
    Ghosh, Devanita
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal, India.
    Dash, Ayusman
    Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal, India.
    Bose, Suatapa
    Earth and Environmental Science Research Laboratory, Department of Earth Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal, India .
    Arsenic Contamination in Soil and Sediment in India: Sources, Effects, and Remediation2015Inngår i: Current Pollution Reports, ISSN 2198-6592, Vol. 1, nr 1, s. 35-46Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Arsenic contamination is turning out to be a major problem these days with its area coverage and the number of people affected directly or indirectly. Now, the level of the contaminant has spread over the soil and sediments from groundwater and other natural sources. Arsenic poisoning in groundwater events is familiar to the world, but the consequences of soil contamination are still unrevealed to the community, specially the people of contaminated counties. Arsenic is a serious instantaneous concern for the people and other life forms regarding the poisoning through crops and vegetables. Many remediation technologies that mainly include physical, chemical, and a few biological methods have been evolved with time to check its effects. The physical and chemical methods for this purpose are often inefficient and/or very expensive, mainly limited to application in aqueous systems, and produce toxic sludge, which again becomes a matter of concern. But bioremediation relies on the fact that biological organisms have the ability to degrade, detoxify, and even accumulate harmful chemicals and offers attractive perspectives for biomonitoring (via biosensors), treatment of wastewater, and the recycling of polluted soils.

  • 22.
    Ulrich, G. A.
    et al.
    Department of Botany and Microbiology, 770 Van Vleet Oval, University of Oklahoma, Norman, OK 73019-0245, USA.
    Martino, D.
    Department of Oceanography, Texas A&M University, College Station, TX 77843, USA.
    Burger, K.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Routh, Joyanto
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Grossman, E. L.
    Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
    Ammerman, J. W.
    Department of Oceanography, Texas A&M University, College Station, TX 77843, USA.
    Suflita, J. M.
    Department of Botany and Microbiology, 770 Van Vleet Oval, University of Oklahoma, Norman, OK 73019-0245, USA.
    Sulfur Cycling in the Terrestrial Subsurface: Commensal Interactions, Spatial Scales, and Microbial Heterogeneity1998Inngår i: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 36, nr 2, s. 141-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microbiological, geochemical, and isotopic analyses of sediment and water samples from the unconsolidated Yegua formation in east-central Texas were used to assess microbial processes in the terrestrial subsurface. Previous geochemical studies suggested that sulfide oxidation at shallow depths may provide sulfate for sulfate-reducing bacteria (SRB) in deeper aquifer formations. The present study further examines this possibility, and provides a more detailed evaluation of the relationship between microbial activity, lithology, and the geochemical environment on meter-to-millimeter scales. Sediment of varied lithology (sands, silts, clays, lignite) was collected from two boreholes, to depths of 30 m. Our findings suggest that pyrite oxidation strongly influences the geochemical environment in shallow sediments ( 5 m), and produces acidic waters (pH 3.8) that are rich in sulfate (28 mM) and ferrous iron (0.3 mM). Sulfur and iron-oxidizing bacteria are readily detected in shallow sediments; they likely play an indirect role in pyrite oxidation. In consistent fashion, there is a relative paucity of pyrite in shallow sediments and a low 34S/32S-sulfate ratio (0.2ᅵ) (reflecting contributions from 34S-depleted sulfides) in shallow regions. Pyrite oxidation likely provides a sulfate source for both oxic and anoxic aquifers in the region. A variety of assays and direct-imaging techniques of 35S-sulfide production in sediment cores indicates that sulfate reduction occurs in both the oxidizing and reducing portions of the sediment profile, with a high degree of spatial variability. Narrow zones of activity were detected in sands that were juxtaposed to clay or lignite-rich sediments. The fermentation of organic matter in the lignite-rich laminae provides small molecular weight organic acids to support sulfate reduction in neighboring sands. Consequently, sulfur cycling in shallow sediments, and sulfate transport represent important mechanisms for commensal interaction among subsurface microorganisms by providing electron donors for chemoautotrophic bacteria and electron acceptors for SRB. The activity of SRB is linked to the availability of suitable electron donors from spatially distinct zones.

  • 23.
    Uren, Ryan
    et al.
    North-West University, South Africa.
    van der Lingen, Carl
    Department of the Environment, South Africa.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Bouwman, Hindrik
    North-West University, South Africa.
    Concentrations and relative compositions of metallic elements differ between predatory squid and filter-feeding sardine from the Indian and South Atlantic oceans2020Inngår i: Regional Studies in Marine Science, ISSN 0080-0694, E-ISSN 2168-1376, Vol. 35, artikkel-id 101137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Although metallic elements occur naturally, they can occur or accumulate in organisms at levels toxic to the organism and/or their consumers. Concentrations of twenty-nine metallic elements in muscle tissue from sardine Sardinops sagax and chokka squid Loligo reynaudii from South Atlantic and Indian Ocean waters off South Africa were established, for the first time, using inductively-coupled plasma mass spectrometry. Chokka showed significantly higher (p < 0.05) concentrations of B, Cr, Zn, As, Se, Rb, Sr, Cd, and Tl and significantly lower concentrations of V, Mn, Ti, and Mo compared to sardine. There were also significant differences in some metallic elements between the two oceans. Multivariate analyses indicated possible population structure of both species, suggesting that these analyses may be useful as a stock discrimination tool. Only two sardine samples contained quantifiable Hg. Based on South African estimated daily intake, total hazard quotient, and European Union limits for Hg, Cd, and Pb, we consider tissues from sardine and chokka in South African waters to be safe for human consumption.

  • 24.
    Valle, Juliana
    et al.
    Helmholtz Zentrum Munich, Germany.
    Gonsior, Michael
    Univ Maryland, MD 20688 USA.
    Harir, Mourad
    Helmholtz Zentrum Munich, Germany; Tech Univ Munich, Germany.
    Enrich Prast, Alex
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Univ Fed Rio de Janeiro, Brazil.
    Schmitt-Kopplin, Philippe
    Helmholtz Zentrum Munich, Germany; Technische Universität München, Freising-Weihenstephan, Germany.
    Bastviken, David
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Conrad, Ralf
    Max Planck Inst Terr Microbiol, Germany.
    Hertkorn, Norbert
    Helmholtz Zentrum Munich, Germany.
    Extensive processing of sediment pore water dissolved organic matter during anoxic incubation as observed by high-field mass spectrometry (FTICR-MS)2018Inngår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 129, s. 252-263Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dissolved organic matter (DOM) contained in lake sediments is a carbon source for many microbial degradation processes, including aerobic and anaerobic mineralization. During anaerobic degradation, DOM is partially consumed and transformed into new molecules while the greenhouse gases methane (CH4) and carbon dioxide (CO2) are produced. In this study, we used ultrahigh resolution mass spectrometry to trace differences in the composition of solid-phase extractable (PPL resin) pore water DOM (SPE-DOM) isolated from surface sediments of three boreal lakes before and after 40 days of anoxic incubation, with concomitant determination of CH4 and CO2 evolution. CH4 and CO2 production detected by gas chromatography varied considerably among replicates and accounted for fractions of similar to 2-4 x 10(-4) of sedimentary organic carbon for CO2 and similar to 0.8-2.4 x 10(-5) for CH4. In contrast, the relative changes of key bulk parameters during incubation, such as relative proportions of molecular series, elemental ratios, average mass and unsaturation, were regularly in the percent range (1-3% for compounds decreasing and 4-10% for compounds increasing), i.e. several orders of magnitude higher than mineralization alone. Computation of the average carbon oxidation state in CHO molecules of lake pore water DOM revealed rather non-selective large scale transformations of organic matter during incubation, with depletion of highly oxidized and highly reduced CHO molecules, and formation of rather non-labile fulvic acid type molecules. In general, proportions of CHO compounds slightly decreased. Nearly saturated CHO and CHOS lipid-like substances declined during incubation: these rather commonplace molecules were less specific indicators of lake sediment alteration than the particular compounds, such as certain oxygenated aromatics and carboxyl-rich alicyclic acids (CRAM) found more abundant after incubation. There was a remarkable general increase in many CHNO compounds during incubation across all lakes. Differences in DOM transformation between lakes corresponded with lake size and water residence time. While in the small lake Svarttjarn, CRAM increased during incubation, lignin-and tannin-like compounds were enriched in the large lake Bisen, suggesting selective preservation of these rather non-labile aromatic compounds rather than recent synthesis. SPE-DOM after incubation may represent freshly synthesized compounds, leftover bulk DOM which is primarily composed of intrinsically refractory molecules and/or microbial metabolites which were not consumed in our experiments. In spite of a low fraction of the total DOM being mineralized to CO2 and CH4, the more pronounced change in molecular DOM composition during the incubation indicates that diagenetic modification of organic matter can be substantial compared to complete mineralization. (C) 2017 Elsevier Ltd. All rights reserved.

  • 25.
    Valle, Juliana
    et al.
    German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Neuherberg, Germany.
    Harir, Mourad
    German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Neuherberg, Germany; Technische Universit€at München, Chair Analytical Food Chemistry, Freising, Weihenstephan, Germany.
    Gonsior, Michael
    University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, USA.
    Enrich Prast, Alex
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Federal University of Rio de Janeiro, Department of Botany, Rio de Janeiro, Brazil.
    Schmitt-Kopplin, Philippe
    German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Neuherberg, Germany; Technische Universit€at München, Chair Analytical Food Chemistry, Freising, Weihenstephan, Germany.
    Bastviken, David
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Hertkorn, Norbert
    German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Neuherberg, Germany.
    Molecular differences between water column and sediment porewater SPE-DOM in ten Swedish boreal lakes2020Inngår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 170, artikkel-id 115320Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Boreal lakes are considered hot spots of dissolved organic matter (DOM) processing within the globalcarbon cycle. This study has used FT-ICR mass spectrometry and comprehensive data evaluation to assessthe molecular differences of SPE-DOM between lake column water SPE-DOM and sedimentary porewater SPE-DOM in 10 Swedish boreal lakes of the Malingsbo area, which were selected for their largediversity of physicochemical and morphological characteristics. While lake column water is well mixedand fairly oxygenated, sedimentary pore water is subject to depletion of oxygen and to confinement ofmolecules. Robust trends were deduced from molecular compositions present in all compartments andin all 10 lakes (“common compositions”) with recognition of relative abundance. Sedimentary pore waterSPE-DOM featured higher proportions of heteroatoms N and S, higher average H/C ratios in presence ofhigher DBE/C ratios, and higher average oxygenation than lake column water SPE-DOM. These trendswere observed in all lakes except Ljustj€arn, which is a ground water fed kettle lake with an unique lakebiogeochemistry. Analogous trends were also observed in case of single or a few lakes and operated alsofor compounds present solely in either lake column water or sedimentary pore water. Unique compoundsdetected in either compartments and/or in a few lakes showed higher molecular diversity thanthe “common compositions”. Processing of DOM molecules in sediments included selective preservationfor polyphenolic compounds and microbial resynthesis of selected molecules of considerable diversity.

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