Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Soils in lakes : the impact of inundation and storage on surface water quality
    Vink, Jos P.M. ; Comans, Rob N.J. ; Dijkstra, Joris J. ; Lamers, Leon P.M. - \ 2020
    Environmental Monitoring and Assessment 192 (2020)6. - ISSN 0167-6369
    Bioavailability - Biotic ligand models - Chemical extraction - Risk assessment - Sediment fluxes - Speciation - Suspended matter - Toxicity

    The large-scale storage and inundation of contaminated soils and sediments in deep waterlogged former sand pits or in lakes have become a fairly common practice in recent years. Decreasing water depth potentially promotes aquatic biodiversity, but it also poses a risk to water quality as was shown in a previous study on the impact on groundwater. To provide in the urgent need for practical and robust risk indicators for the storage of terrestrial soils in surface waters, the redistribution of metals and nutrients was studied in long-term mesocosm experiments. For a range of surface water turbidity (suspended matter concentrations ranging from 0 to 3000 mg/L), both chemical partitioning and toxicity of pollutants were tested for five distinctly different soils. Increasing turbidity in surface water showed only marginal response on concentrations of heavy metals, phosphorus (P) and nitrogen (N). Toxicity testing with bioluminescent bacteria, and biotic ligand modelling (BLM), indicated no or only minor risk of metals in the aerobic surface water during aerobic mixing under turbid conditions. Subsequent sedimentation of the suspended matter revealed the chemical speciation and transport of heavy metals and nutrients over the aerobic and anaerobic interface. Although negative fluxes occur for Cd and Cu, most soils show release of pollutants from sediment to surface waters. Large differences in fluxes occur for PO4, SO4, B, Cr, Fe, Li, Mn and Mo between soils. For an indicator of aerobic chemical availability, dilute nitric acid extraction (0.43 M HNO3; Aqua nitrosa) performed better than the conventional Aqua regia destruction. Both the equilibrium concentrations in surface waters, and fluxes from sediment, were adequately (r2 = 0.81) estimated by a 1 mM CaCl2 soil extraction procedure. This study has shown that the combination of 0.43 M HNO3 and 1 mM CaCl2 extraction procedures can be used to adequately estimate emissions from sediment to surface waters, and assess potential water quality changes, when former sand pits are being filled with soil materials.

    Rapid metal mobilisation through litter, water and bioweathering as the legacy of historical copper smelting
    Potysz, Anna ; Pędziwiatr, Artur ; Hedwig, Sebastian ; Lenz, Markus - \ 2019
    Journal of Geochemical Exploration 206 (2019). - ISSN 0375-6742
    Metals - Mineral phases - Organic extracts - Slag - Toxicity - Zea mays

    Though activities have long ceased, historical mining sites may continue to represent a risk to the environment and human health through long-time leaching processes. This study was undertaken to assess the immediate environmental risk posed by historic metallurgical slags upon contact with litter (Fagus sylvatica leaves, Picea abies needles) and stream water. Further, the contribution of direct slag phase bioweathering was investigated using a soil solution favouring microbial growth (biostimulation) versus aqueous sterile soil extracts. The slags' exposure to Acidithiobacillus thiooxidans mimicked the extremely acidic conditions that will eventually develop under long-term weathering of the sulfidic phases present in the slags (e.g. bornite, chalcopyrite). The risk of metal mobilisation was assessed by means of both bio-chemical leaching experiments (quantification by triple quadrupole inductively coupled plasma mass spectrometry QQQ-ICP-MS) as well as phytotoxicity (Zea mays germination; direct contact and soil pot experiments). Potential metal donor slag phases were identified by scanning electron microscopy (SEM-EDS). It was shown that slags would be categorised as hazardous waste when remaining in contact with the studied weathering solutions. Lead was the most mobile element leaching from slags (up to 86%) and exceeded the legal limits for classification as a non-hazardous waste for all executed treatments. Biostimulation had little effect on Cu leaching (up to 2.6% versus 2.5% for the sterile soil extract, respectively). Litter derived solutions, in contrast, enhanced glass dissolution instead of heavy metal bearing phases. Metal leaching was rapid, raising concerns for peak loads on slag exposure to changing biogeochemical conditions. Extremely acidic conditions and bioleaching by A. thiooxidans were shown to result in metal-enriched leachates (up to 92% of Zn) as well as the lowest germination rate in Zea mays, implying a long term risk by sulphide bioweathering. Five week pot experiments with a soil/slag mixture and Zea mays revealed poor growth in all studied conditions. However, a bacterially derived citric acid was found to improve root and shoot development, possibly due to alleviating the toxic effect of some elements. Due to the observed phytotoxicity, we conclude that the phytoremediation/rehabilitation of slag impacted soils may be limited. The search for a metal tolerant plant species that would be efficient in terms of biomass production and metals uptake is a perspective of this work.

    Response of sediment bacterial community to triclosan in subtropical freshwater benthic microcosms
    Peng, Feng Jiao ; Diepens, Noël J. ; Pan, Chang Gui ; Ying, Guang Guo ; Salvito, Daniel ; Selck, Henriette ; Brink, Paul J. Van den - \ 2019
    Environmental Pollution 248 (2019). - ISSN 0269-7491 - p. 676 - 683.
    Benthic macroinvertebrates - Microcosm - Sediment bacterial community - Toxicity - Triclosan

    The response of sediment bacterial communities in subtropical freshwater benthic microcosms to sediment-associated triclosan (TCS; 28 d exposure) was analysed using Illumina high-throughput sequencing. This study highlights the interactive effects of TCS and the presence of benthic macroinvertebrates (Limnodrilus hoffmeisteri and Viviparidae bellamya) on sediment bacterial communities. Our results show that TCS alone significantly altered the taxonomic composition and decreased alpha diversity of sediment bacterial communities at concentrations ≥80 μg TCS/g dry weight (dw) sediment (sed). Regarding dominant phyla, TCS significantly reduced the relative abundance of Bacteroidetes and Firmicutes at these concentrations, whereas the relative abundance of Chloroflexi and Cyanobacteria increased. In the presence of benthic macroinvertebrates, the sediment bacterial community was affected by 8 μg TCS/g dw sed as well. However, the presence of benthic macroinvertebrates did not cause measurable changes to bacterial community in unspiked (i.e., control) sediment. These results indicate that TCS alone would not alter the sediment bacterial community at environmentally relevant concentrations (up till 8 μg/g dw sed), but may have an effect in combination with the presence of benthic macroinvertebrates. Therefore, we recommend to include benthic macroinvertebrates when assessing the response of sediment bacterial communities during exposure to environmental stress such as organic contaminants.

    Fate and effects of sediment-associated polycyclic musk HHCB in subtropical freshwater microcosms
    Peng, Feng Jiao ; Kiggen, Fionne ; Pan, Chang Gui ; Bracewell, Sally A. ; Ying, Guang Guo ; Salvito, Daniel ; Selck, Henriette ; Brink, Paul J. Van den - \ 2019
    Ecotoxicology and Environmental Safety 169 (2019). - ISSN 0147-6513 - p. 902 - 910.
    Bacterial community - Benthic macroinvertebrates - Bioaccumulation - Dissipation - HHCB - Toxicity

    Galaxolide (HHCB) is used as a fragrance ingredient in household and personal care products, and has been ubiquitously detected in the environment. Here we investigated the fate of HHCB in subtropical freshwater microcosms, and evaluated effects of sediment-associated HHCB on a biological community consisting of algae, Daphnia, benthic macroinvertebrates and bacteria. The concentrations of sediment-associated HHCB did not change significantly during a 28 days exposure period, but HHCB accumulated in worms with biota-sediment accumulation-factor (BSAF) values in the range of 0.29–0.66 for Branchiura sowerbyi and 0.94–2.11 for Limnodrilus hoffmeisteri. There was no significant effects of HHCB (30 μg/g dry weight (dw) sediment) on chlorophyll-a content, sediment bacterial community composition, and survival and growth of benthic macroinvertebrates. However, the presence of benthic macroinvertebrates altered the sediment bacterial community structure relative to microcosms without introduced organisms. The findings of this study suggest that a single high-dose of HHCB, over 28 days, at environmentally relevant concentrations would not impose direct toxicological risks to aquatic organisms such as benthic macroinvertebrates.

    Body composition is associated with risk of toxicity-induced modifications of treatment in women with stage I–IIIB breast cancer receiving chemotherapy
    Berg, Maaike M.G.A. van den; Kok, Dieuwertje E. ; Posthuma, Liesbeth ; Kamps, Lisette ; Kelfkens, Celine S. ; Buist, Nicole ; Geenen, Maud ; Haringhuizen, Annebeth ; Heijns, Joan B. ; Lieshout, Rianne H.M.A. van; Los, Maartje ; Sommeijer, Dirkje W. ; Timmer-Bonte, Johanna N.H. ; Kruif, Anja Th.C.M. de; Laarhoven, Hanneke W.M. van; Kampman, Ellen ; Winkels, Renate M. - \ 2019
    Breast Cancer Research and Treatment 173 (2019)2. - ISSN 0167-6806 - p. 475 - 481.
    Body composition - Breast cancer - Chemotherapy - Fat mass - Toxicity

    Purpose: Initial dose of chemotherapy is planned based on body surface area, which does not take body composition into account. We studied the association between fat mass (kg and relative to total body weight) as well as lean mass (kg and relative to total body weight) and toxicity-induced modifications of treatment in breast cancer patients receiving chemotherapy. Methods: In an observational study among 172 breast cancer patients (stage I–IIIB) in the Netherlands, we assessed body composition using dual-energy X-ray scans. Information on toxicity-induced modifications of treatment, defined as dose reductions, cycle delays, regimen switches, or premature termination of chemotherapy, was abstracted from medical records. Adjusted hazard ratios and 95% confidence intervals (95% CI) were calculated to assess associations between body composition and the risk of toxicity-induced modifications of treatment. Results: In total, 95 out of 172 (55%) patients experienced toxicity-induced modifications of treatment. Higher absolute and relative fat mass were associated with higher risk of these modifications (HR 1.14 per 5 kg; 95% CI 1.04–1.25 and HR 1.21 per 5%; 95% CI 1.05–1.38, respectively). A higher relative lean mass was associated with a lower risk of modifications (HR 0.83 per 5%; 95% CI 0.72–0.96). There was no association between absolute lean mass and risk of toxicity-induced modifications of treatment. Conclusions: A higher absolute and a higher relative fat mass was associated with an increased risk of toxicity-induced modifications of treatment. Absolute lean mass was not associated with risk of these treatment modifications, while higher relative lean mass associated with lower risk of modifications. These data suggest that total fat mass importantly determines the risk of toxicities during chemotherapy in breast cancer patients.

    Toxicity-induced modification of treatment : what is in a name?
    Kok, Dieuwertje E. ; Winkels, Renate M. ; Herpen, Carla M.L. van; Kampman, Ellen - \ 2018
    European Journal of Cancer 104 (2018). - ISSN 0959-8049 - p. 145 - 150.
    Body composition - Cancer - Definition - Determinants - Toxicity - Treatment modification

    Severe treatment-induced toxicities can have clinical consequences such as hospitalisation or treatment modifications, which in turn may deteriorate the prognosis of patients with cancer. Identification of determinants of treatment-induced toxicities is essential to develop strategies that promote therapy compliance and enhance the quality of life. Whereas toxicities are systematically recorded and graded per protocol in most clinical trials, observational studies often depend on retrospective data collection from medical records collected as standard care. Existing population-based or patient cohorts are a valuable source of information, even when relying on retrospective data collection, but comparisons across studies are hampered by a lack of a uniform definition for toxicity outcomes. We propose a new standardised approach to summarise toxicities in observational studies that rely on medical records for outcome assessment. We recommend the term ‘toxicity-induced modification of treatment’ (TIMT) to cover all toxicities that are responsible for changes in a planned treatment schedule. We define a TIMT as (i) a dose reduction, (ii) temporary interruption, (iii) discontinuation of therapy or (iv) an unanticipated switch to another regimen, as a result of treatment-induced toxicities and not because of progressive disease. This definition will provide clinically relevant information, especially when data on specific adverse events and Common Terminology Criteria for Adverse Events (CTCAE) grades are not uniformly available. Implementation of this definition empowers comparisons across studies, facilitates communication between clinicians and researchers and will allow new research questions in this active field of research.

    Models of Geochemical Speciation : Structure and Applications
    Bonito, Marcello Di; Lofts, Sthephen ; Groenenberg, Jan E. - \ 2018
    In: Environmental Geochemistry / De Vivo, Benedetto, Belkin, Harvey E., Lima, Annamaria, Elsevier - ISBN 9780444637635 - p. 237 - 305.
    Bioavailability - Biotic-ligand model - Ion-binding - Modeling - Speciation - Surface complexation - Thermodynamic databases - Toxicity

    Being able to predict the behavior of trace elements in the environment is crucial for environmental risk assessment studies. For this reason, modeling, in addition to experimental methods, has become an indispensable tool to better understand the (bio)-geochemistry of trace elements and the processes involved in their availability, transport and ecotoxicity. In this chapter we briefly outline the development of geochemical modeling over time and its basic principles. A comprehensive description of the state-of-the-art ion-binding and surface complexation models presently available for dissolved and particulate organic matter, metal (hydr)oxides of aluminum, iron, manganese and silica and clay minerals is given. A significant part of this chapter is dedicated to the application of these models for studying surface waters and soils. The most common model platforms used for this purpose together with the available (thermodynamic) databases of model parameters are summarized. In two separate sections we highlight the application of an assemblage model (with submodels for the various adsorbents) to describe trace element solid-solution partitioning and speciation in surface waters and soils; here particular attention is given to the derivation of site-specific inputs concerning the geochemical reactive metal content and the contents of adsorbents metal (hydr)oxides, clay and organic matter). Consideration is therefore given to the most recent developments in bio-geochemical modeling to link metal speciation to bioavailability, biotic accumulation and toxicity. Finally, future prospects of geochemical modeling are discussed, giving an overview of the potential directions for development.

    Fate and effects of sediment-associated triclosan in subtropical freshwater microcosms
    Peng, Feng-Jiao ; Diepens, Noël J. ; Pan, Chang-Gui ; Bracewell, Sally A. ; Ying, Guang-Guo ; Salvito, Daniel ; Selck, Henriette ; Brink, Paul J. Van den - \ 2018
    Aquatic Toxicology 202 (2018). - ISSN 0166-445X - p. 117 - 125.
    Benthic macroinvertebrates - Bioaccumulation - Dissipation - Partitioning - Toxicity

    Triclosan (TCS) is an antibacterial agent that is commonly used in personal care products. Because of its sediment-binding properties, TCS exposure presents a potential threat to sediment-dwelling aquatic organisms. Currently our knowledge of the fate and effects of sediment-associated TCS in aquatic systems is limited. To understand the impact of sediment-associated TCS, we used microcosms to assess effects of TCS exposure on a diverse range of organisms selected to mimic a subtropical community, with an exposure period of 28 days. We included the oligochaete freshwater worm Limnodrilus hoffmeisteri to evaluate the interaction between sediment-associated TCS and sediment-dwelling organisms, including potential loss of TCS from the sediment due to biological activity and bioaccumulation. Benthic macroinvertebrate presence significantly increased the TCS levels from 0.013 ± 0.007 μg/L to 0.613 ± 0.030 μg/L in the overlying water through biological activity, posing a potential additional risk to pelagic species, but it did not result in a significant reduction of the sediment concentration. Furthermore, worms accumulated TCS with estimated Biota-Sediment-Accumulation-Factors (BSAFs) ranging between 0.38–3.55. Other than for algae, TCS at environmental concentrations did not affect the survival of the introduced organisms, including the L. hoffmeisteri. Our results demonstrate that, although TCS at currently detected maximum concentration may not have observable toxic effects on the benthic macroinvertebrates in the short term, it can lead to bioaccumulation in worms.

    Enhanced pharmaceutical removal from water in a three step bio-ozone-bio process
    Wilt, Arnoud de; Gijn, Koen van; Verhoek, Tom ; Vergnes, Amber ; Hoek, Mirit ; Rijnaarts, Huub ; Langenhoff, Alette - \ 2018
    Water Research 138 (2018). - ISSN 0043-1354 - p. 97 - 105.
    Biodegradation - Combined treatment - Ozonation - Pharmaceuticals - Toxicity - Wastewater
    Individual treatment processes like biological treatment or ozonation have their limitations for the removal of pharmaceuticals from secondary clarified effluents with high organic matter concentrations (i.e. 17 mg TOC/L). These limitations can be overcome by combining these two processes for a cost-effective pharmaceutical removal. A three-step biological-ozone-biological (BO3B) treatment process was therefore designed for the enhanced pharmaceutical removal from wastewater effluent. The first biological step removed 38% of ozone scavenging TOC, thus proportionally reducing the absolute ozone input for the subsequent ozonation. Complementariness between biological and ozone treatment, i.e. targeting different pharmaceuticals, resulted in cost-effective pharmaceutical removal by the overall BO3B process. At a low ozone dose of 0.2 g O3/g TOC and an HRT of 1.46 h in the biological reactors, the removal of 8 out of 9 pharmaceuticals exceeded 85%, except for metoprolol (60%). Testing various ozone doses and HRTs revealed that pharmaceuticals were ineffectively removed at 0.1 g O3/g TOC and an HRT of 0.3 h. At HRTs of 0.47 and 1.46 h easily and moderately biodegradable pharmaceuticals such as caffeine, gemfibrozil, ibuprofen, naproxen and sulfamethoxazole were over 95% removed by biological treatment. The biorecalcitrant carbamazepine was completely ozonated at a dose of 0.4 g O3/g TOC. Ozonation products are likely biodegraded in the last biological reactor as a 17% TOC removal was found. No appreciable acute toxicity towards D. magna, P. subcapitata and V. fischeri was found after exposure to the influents and effluents of the individual BO3B reactors. The BO3B process is estimated to increase the yearly wastewater treatment tariff per population equivalent in the Netherlands by less than 10%. Overall, the BO3B process is a cost-effective treatment process for the removal of pharmaceuticals from secondary clarified effluents.
    Triclosan-induced transcriptional and biochemical alterations in the freshwater green algae Chlamydomonas reinhardtii
    Pan, Chang Gui ; Peng, Feng-Jiao ; Shi, Wen Jun ; Hu, Li Xin ; Wei, Xiao Dong ; Ying, Guang Guo - \ 2018
    Ecotoxicology and Environmental Safety 148 (2018). - ISSN 0147-6513 - p. 393 - 401.
    Biochemical alteration - Chlamydomonas reinhardtii - Gene expression - Growth - Toxicity - Triclosan

    Triclosan (TCS) is an antibacterial and antifungal agent widely used in personal care products (PCPs). We investigated the effects of TCS (20 μg/L, 100 μg/L and 500 μg/L) on Chlamydomonas reinhardtii by measuring the algal growth, chlorophyll content, lipid peroxidation, and transcription of the antioxidant-related genes (superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), glutathione S-transferase (GST), plastid terminal oxidase 2 (PTOX) and thioredoxin (TRX)) as well as biochemical alterations. The results showed significant dose-related effects of TCS on the algal species in terms of growth and chlorophyll content. Malondialdehyde (MDA) increased with increasing TCS concentrations and showed significant difference between the treatment of 405.3 μg/L TCS and control group. Transcription analysis revealed that the expression of SOD mRNA was most sensitive to TCS among the selected genes. In addition, Fourier-transform infrared spectroscopy showed time- and concentration-specific biochemical responses in C. reinhardtii when exposed to TCS. The biochemical alterations associated with different doses of TCS were mainly attributed to structural changes associated with lipid, protein, nucleic acid and carbohydrate. The findings from this study reveal that TCS in the aquatic environment may affect algal growth, chlorophyll synthesis, oxidative stress responses and cause biochemical alterations. This study provided important information to achieve a better understanding of the toxic mechanism of triclosan on algae Chlamydomonas reinhardtii.

    Body Composition in Relation to Clinical Outcomes in Renal Cell Cancer : A Systematic Review and Meta-analysis
    Vrieling, Alina ; Kampman, Ellen ; Knijnenburg, Nathalja C. ; Mulders, Peter F. ; Sedelaar, J.P.M. ; Baracos, Vickie E. ; Kiemeney, Lambertus A. - \ 2018
    European Urology Focus 4 (2018)3. - ISSN 2405-4569 - p. 420 - 434.
    Body composition - Perinephric fat - Perioperative outcomes - Recurrence - Renal cell cancer - Skeletal muscle - Survival - Toxicity - Visceral adipose tissue
    Context: Several studies suggest that body composition (ie, body proportions of muscle and fat defined by computed tomography) is associated with clinical outcomes of several cancer types, including renal cell cancer (RCC). Objective: To conduct a systematic review and meta-analysis of the evidence on body composition in relation to clinical outcomes in RCC. Evidence acquisition: Literature was reviewed through October 2016 using PubMed and Embase. We included studies investigating computed tomography-measured cross-sectional areas of visceral adipose tissue (VAT), perinephric fat, subcutaneous adipose tissue (SAT), skeletal muscle index (SMI), and skeletal muscle radiodensity (SMD) in relation to perioperative outcomes, treatment toxicity, and survival in RCC patients. Evidence synthesis: We included 28 studies with a total of 6608 patients. Binary classification of body composition was used in most studies. In metastatic RCC (mRCC) patients treated with antiangiogenic drugs, dose-limiting toxicity was more frequent in patients with low versus high SMI (four studies, risk difference = 16%, 95% confidence interval [CI]: 2-31%, p = 0.03, I2 = 26%). Low versus high SMI (six studies, hazard ratio = 1.48, 95% CI: 1.08-2.03, p = 0.02, I2 = 28%) and SMD (four studies, HR = 1.56, 95% CI: 1.20-2.03, p = 0.0008, I2 = 0%) were associated with an increased risk of overall mortality in mRCC. Low versus high VAT and perinephric fat were not consistently associated with perioperative outcomes and survival. No associations for SAT were found. Conclusions: Low SMI is associated with increased dose-limiting toxicity, and low SMI and SMD are associated with increased overall mortality in mRCC. The association of VAT, perinephric fat, and SAT with clinical outcomes needs further investigation, also in localized RCC. Patient summary: We reviewed studies assessing the association of body composition with clinical outcomes in renal cell cancer. We demonstrated higher risk of dose-limiting toxicity and overall mortality for metastatic renal cell cancer patients with low versus high skeletal muscle index or skeletal muscle radiodensity, but observed inconsistent associations with visceral adipose tissue and perinephric fat. This review shows that low skeletal muscle mass is associated with increased dose-limiting toxicity and overall mortality in metastatic renal cell cancer. Visceral adipose tissue and perinephric fat were not consistently associated with clinical outcomes in renal cell cancer.
    Gastrointestinal System
    Jepson, Mark A. ; Bouwmeester, Hans - \ 2017
    In: Adverse Effects of Engineered Nanomaterials / Fadeel, Bengt, Pietroiusti, Antonio, Shvedova, Anna A., Elsevier Inc. Academic Press - ISBN 9780128091999 - p. 381 - 396.
    Gastrointestinal tract - Nanomaterials - Nanotechnology - Respiratory tract - Toxicity

    The epithelial lining of the gastrointestinal tract (GIT) acts as a barrier to uptake of potentially dangerous material while allowing absorption of processed food. The gut may be exposed to a diverse range of engineered nanomaterials due to their deliberate addition to food and consumer products and in the form of particulate delivery vehicles for drugs and vaccines, and inadvertently via contaminated food and water and after efflux of material from the respiratory tract. The extent of inadvertent ingestion of nanomaterials is not currently known, but it is nevertheless prudent to assess interactions of nanomaterials with GIT cells in order to assess the potential impact of nanomaterial uptake. Although nanomaterial toxicity within the GIT has been much less extensively studied than that at other interfaces or compartments, over the past decade a number of studies have begun to address the impact, behavior, and interaction of nanomaterials in the GIT. Some reports suggest that GIT cells may be less responsive to nanomaterial toxicity, but it is also clear that nanomaterials may affect the function of cultured GIT epithelial cells in ways that are not detected by standard toxicity assays. This chapter summarizes the current knowledge of the uptake and potential toxicity of nanomaterials in the gut and highlights potential research priorities.

    Growth of four tropical tree species in petroleum-contaminated soil and effects of crude oil contamination
    Pérez-Hernández, I. ; Ochoa-Gaona, S. ; Adams, R.H. ; Rivera-Cruz, M.C. ; Pérez-Hernández, V. ; Jarquín-Sánchez, A. ; Geissen, V. ; Martínez-Zurimendi, P. - \ 2017
    Environmental Science and Pollution Research 24 (2017)2. - ISSN 0944-1344 - p. 1769 - 1783.
    Hydrocarbons - Remediation - Stress - Tolerance - Toxicity - Trees
    Under greenhouse conditions, we evaluated establishment of four tree species and their capacity to degrade crude oil recently incorporated into the soil; the species were as follows: Cedrela odorata (tropical cedar), Haematoxylum campechianum (tinto bush), Swietenia macrophylla (mahogany), and Tabebuia rosea (macuilis). Three-month-old plants were planted in soil with three treatments of heavy petroleum and a control (C0 0 mg kg−1; C1 18,000 mg kg−1; C2 31,700 mg kg−1; C3 47,100 mg kg−1) with four repetitions per treatment and species; the experiment was carried out for 245 days. Height and biomass of all species significantly diminished as petroleum concentration increased, although plant survival was not affected. The quantity of colony-forming units (CFU) of rhizospheric bacteria varied among tree species and treatments; petroleum stimulated bacterial CFU for S. macrophylla. The number of fungi CFU for S. macrophylla and T. rosea was significantly greater in C0 than in soil with petroleum, but among species and among different concentrations, no significant differences were found. The greatest percentage of total petroleum hydrocarbon (TPH) degradation was found in C1 for soil without plants (45 %). Differences from the remaining treatments (petroleum concentrations in soil and plant species) were not significant (P <0.05). Among all trees, H. campechianum had the greatest TPH degradation (32.5 % in C2). T. rosea (C1) and H. campechianum (C2) resulted in petroleum degradation at levels ranging from 20.5 to 32.5 %. On the basis of this experiment, the tree species used did not improve TPH degradation. However, all of them showed high rates of survival and vigor. So, as tree species provide goods and services, experiments with inoculation of hydrocarbonclastic microorganisms, addition of fertilizers, and mixture of tree and grasses are recommended.
    Biotechnological production of limonene in microorganisms
    Jongedijk, Esmer ; Cankar, Katarina ; Buchhaupt, Markus ; Schrader, Jens ; Bouwmeester, Harro ; Beekwilder, Jules - \ 2016
    Applied Microbiology and Biotechnology 100 (2016)7. - ISSN 0175-7598 - p. 2927 - 2938.
    Biomaterial - Limonene - Metabolic engineering - Microbial production - Monoterpene - Toxicity

    This mini review describes novel, biotechnology-based, ways of producing the monoterpene limonene. Limonene is applied in relatively highly priced products, such as fragrances, and also has applications with lower value but large production volume, such as biomaterials. Limonene is currently produced as a side product from the citrus juice industry, but the availability and quality are fluctuating and may be insufficient for novel bulk applications. Therefore, complementary microbial production of limonene would be interesting. Since limonene can be derivatized to high-value compounds, microbial platforms also have a great potential beyond just producing limonene. In this review, we discuss the ins and outs of microbial limonene production in comparison with plant-based and chemical production. Achievements and specific challenges for microbial production of limonene are discussed, especially in the light of bulk applications such as biomaterials.

    Annual sulfate budgets for Dutch lowland peat polders : The soil is a major sulfate source through peat and pyrite oxidation
    Vermaat, Jan E. ; Harmsen, Joop ; Hellmann, Fritz A. ; Geest, Harm G. van der; Klein, Jeroen J.M. de; Kosten, Sarian ; Smolders, Alfons J.P. ; Verhoeven, Jos T.A. ; Mes, Ron G. ; Ouboter, Maarten - \ 2016
    Journal of Hydrology 533 (2016). - ISSN 0022-1694 - p. 515 - 522.
    Internal eutrophication - Peat mineralization - Pyrite - Subsidence - Toxicity - Water level management

    Annual sulfate mass balances have been constructed for four low-lying peat polders in the Netherlands, to resolve the origin of high sulfate concentrations in surface water, which is considered a water quality problem, as indicated amongst others by the absence of sensitive water plant species. Potential limitation of these plants to areas with low sulfate was analyzed with a spatial match-up of two large databases. The peat polders are generally used for dairy farming or nature conservation, and have considerable areas of shallow surface water (mean 16%, range 6-43%). As a consequence of continuous drainage, the peat in these polders mineralizes causing subsidence rates generally ranging between 2 and 10mmy- 1. Together with pyrite oxidation, this peat mineralization the most important internal source of sulfate, providing an estimated 96kgSO4ha- 1mm- 1subsidencey- 1. External sources are precipitation and water supplied during summer to compensate for water shortage, but these were found to be minor compared to internal release. The most important output flux is discharge of excess surface water during autumn and winter. If only external fluxes in and out of a polder are evaluated, inputs average 37±9 and exports 169±17kgSha- 1y- 1. During summer, when evapotranspiration exceeds rainfall, sulfate accumulates in the unsaturated zone, to be flushed away and drained off during the wet autumn and winter. In some polders, upward seepage from early Holocene, brackish sediments can be a source of sulfate. Peat polders export sulfate to the regional water system and the sea during winter drainage. The available sulfate probably only plays a minor role in the oxidation of peat: we estimate that this is less than 10% whereas aerobic mineralization is the most important. Most surface waters in these polders have high sulfate concentrations, which generally decline during the growing season when aquatic sediments are a sink. In the sediment, this sulfur is reduced and binds iron more strongly than phosphorus, which can be released to the overlying water and potentially fuels eutrophication. About 76% of the sampled vegetation-sites exceeded a threshold of 50mgl- 1SO4, above which sensitive species, such as Stratiotes aloides, and several species of Potamogeton were significantly less abundant. Thus high sulfate concentrations, mainly due to land drainage and consequent mineralization, appear to affect aquatic plant community composition.

    Flow-through real time bacterial biosensor for toxic compounds in water
    Eltzov, Evgeni ; Marks, Robert S. ; Voost, Stefan ; Wullings, Bart A. ; Heringa, Minne B. - \ 2009
    Sensors and Actuators B: Chemical 142 (2009)1. - ISSN 0925-4005 - p. 11 - 18.
    Bioreporter bacteria - Biosensors - Fiber optic - Toxicity

    A flow-through fiber-optic-based bacterial monitoring system for online monitoring of toxic pollutants in water has been developed. Two bacterial strains containing fusions of recA (DNA damage) and grpE (heat-shock) promoters to the lux operon (CDABE) were immobilized on a fiber optic and tested for their ability to detect pollutants in flowing tap water and surface water. Conditions for running the system for 24 h were optimized and first experiments with the system show (1-h) response times and response heights similar to the previous static systems. Responses were related to the doses and the sensitivity is good (comparable to static systems), but needs to be increased to be able to monitor whether also the low guideline values are exceeded by pollutants. 24-h measurements in tap water demonstrate the ability of the device to run for such a time period, but in river water loss of functionality of the bacteria was observed. This flow-through fiber-optic-based monitoring system has proven to be a useful next step in the development of a simple on-line real time sensor for relevant human toxicants in flowing water.

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