Publications by authors named "Marc Peters"

20 Publications

  • Page 1 of 1

Life-Saving Emergency Adrenalectomy in a Pheochromocytoma Crisis with Cardiogenic Shock.

Case Rep Cardiol 2021 18;2021:8848893. Epub 2021 Mar 18.

Intensive Care Medicine, Antwerp University Hospital, University of Antwerp, Edegem, Belgium.

Cardiogenic shock during a pheochromocytoma crisis is a life-threatening disorder. This case report illustrates a 49-year-old male with profound cardiogenic shock, extreme hemodynamic instability (systolic blood pressure ranging from 45 up to 290 mmHg in a cyclic pattern), and progressive multiple organ failure in the presence of a unilateral adrenal mass. Emergency adrenalectomy led to rapid hemodynamic stabilization. Histological investigation confirmed the diagnosis of pheochromocytoma. This case indicates that emergency adrenalectomy, although usually not considered first choice, is a valid option in cardiogenic shock and extremely fluctuating hemodynamics due to a pheochromcytoma-induced catecholamine storm.
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http://dx.doi.org/10.1155/2021/8848893DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996044PMC
March 2021

Contamination patterns in river water from rural Beijing: A hydrochemical and multiple stable isotope study.

Sci Total Environ 2019 Mar 3;654:226-236. Epub 2018 Nov 3.

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.

The pollution of urban river has reached a critical level. In the present study, the hydrochemical composition of local surface water collected during two seasons from the rural area around urban Beijing, China, was examined. Concentrations of selected cations and anions reveal the temporal and spatial distribution of anthropogenic and natural pollution. Multiple stable isotopes (δN, δO, δS, δO, ΔS) analyses were applied for detecting of specific hydrochemical processes and identifying the major sources of contamination. Twenty-eight percent of the river water samples from the wet season and 34% from the dry season exhibit a minor water quality of class IV (poor) and below due to high pH values as well as high nitrate, sulfate and fluoride concentrations. This water is hazardous for human health and the aquatic ecology. The seemingly better river water quality in the wet season is caused by higher precipitation and, hence, dilution of the water constituents. Multiple isotopes identify urban wastewater as the prime pollution source. The higher fraction of deteriorated river water in the southern rural area (42%) compared to the north (24%) points to a higher contribution of urban effluents to the downstream rivers in the rural south. It can, thus, be concluded that less discharge of wastewater to the local surface and subsurface environments by better controls of public and private sewage disposal combined with the renewal of leaking sewer pipes would reduce the risk of anthropogenic contamination of river water.
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http://dx.doi.org/10.1016/j.scitotenv.2018.10.423DOI Listing
March 2019

Multiple Sulfur Isotope Constraints on Sources and Formation Processes of Sulfate in Beijing PM Aerosol.

Environ Sci Technol 2017 Jul 29;51(14):7794-7803. Epub 2017 Jun 29.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China.

Recently air pollution is seriously threatening the health of millions of people in China. The multiple sulfur isotopic composition of sulfate in PM samples collected in Beijing is used to better constrain potential sources and formation processes of sulfate aerosol. The ΔS values of sulfate in PM show a pronounced seasonality with positive values in spring, summer and autumn and negative values in winter. Positive ΔS anomalies are interpreted to result from SO photolysis with self-shielding, and may reflect air mass transport between the troposphere and the stratosphere. The negative ΔS signature (-0.300‰ < ΔS < 0‰) in winter is possibly related to incomplete combustion of coal in residential stoves during the heating season, implying that sulfur dioxide released from residential stoves in more rural areas is an important contributor to atmospheric sulfate. However, negative ΔS anomalies (-0.664‰ < ΔS ← 0.300‰) in winter and positive ΔS anomalies (0.300‰ < ΔS < 0.480‰) in spring, summer, and autumn suggest sulfur isotopic equilibrium on an annual time frame, which may provide an implication for the absence of mass-independent fractionation of sulfur isotopes (S-MIF) in younger sediments. Results obtained here reveal that reducing the usage of coal and improving the heating system in rural areas will be important for efficiently decreasing the emissions of sulfur in China and beyond.
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http://dx.doi.org/10.1021/acs.est.7b00280DOI Listing
July 2017

Chromatographic Separation of Cd from Plants via Anion-Exchange Resin for an Isotope Determination by Multiple Collector ICP-MS.

Anal Sci 2017 ;33(3):335-341

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences.

In this study, key factors affecting the chromatographic separation of Cd from plants, such as the resin column, digestion and purification procedures, were experimentally investigated. A technique for separating Cd from plant samples based on single ion-exchange chromatography has been developed, which is suitable for the high-precision analysis of Cd isotopes by multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The robustness of the technique was assessed by replicate analyses of Cd standard solutions and plant samples. The Cd yields of the whole separation process were higher than 95%, and the Cd values of three Cd second standard solutions (Münster Cd, Spex Cd, Spex-1 Cd solutions) relative to the NIST SRM 3108 were measured accurately, which enabled the comparisons of Cd isotope results obtained in other laboratories. Hence, stable Cd isotope analyses represent a powerful tool for fingerprinting specific Cd sources and/or examining biogeochemical reactions in ecological and environmental systems.
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http://dx.doi.org/10.2116/analsci.33.335DOI Listing
January 2018

Synaptic transmission parallels neuromodulation in a central food-intake circuit.

Elife 2016 11 15;5. Epub 2016 Nov 15.

Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany.

NeuromedinU is a potent regulator of food intake and activity in mammals. In , neurons producing the homologous neuropeptide hugin regulate feeding and locomotion in a similar manner. Here, we use EM-based reconstruction to generate the entire connectome of hugin-producing neurons in the larval CNS. We demonstrate that hugin neurons use synaptic transmission in addition to peptidergic neuromodulation and identify acetylcholine as a key transmitter. Hugin neuropeptide and acetylcholine are both necessary for the regulatory effect on feeding. We further show that subtypes of hugin neurons connect chemosensory to endocrine system by combinations of synaptic and peptide-receptor connections. Targets include endocrine neurons producing DH44, a CRH-like peptide, and insulin-like peptides. Homologs of these peptides are likewise downstream of neuromedinU, revealing striking parallels in flies and mammals. We propose that hugin neurons are part of an ancient physiological control system that has been conserved at functional and molecular level.
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http://dx.doi.org/10.7554/eLife.16799DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5182061PMC
November 2016

Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils.

Environ Sci Pollut Res Int 2016 Dec 9;23(23):23406-23414. Epub 2016 Sep 9.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing, 100101, China.

Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δO) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L NaHCO (pH = 8.5), 0.1 mol L NaOH and 1 mol L HCl) of agricultural soils from the Beijing area. The δO results of the water extracts and NaHCO extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δO value of the water extracts and NaHCO extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δO values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δO values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δO values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils.
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http://dx.doi.org/10.1007/s11356-016-7482-7DOI Listing
December 2016

Central relay of bitter taste to the protocerebrum by peptidergic interneurons in the Drosophila brain.

Nat Commun 2016 09 13;7:12796. Epub 2016 Sep 13.

Department of Molecular Brain Physiology and Behavior, Life and Medical Sciences Institute (LIMES), University of Bonn, 53115 Bonn, Germany.

Bitter is a taste modality associated with toxic substances evoking aversive behaviour in most animals, and the valence of different taste modalities is conserved between mammals and Drosophila. Despite knowledge gathered in the past on the peripheral perception of taste, little is known about the identity of taste interneurons in the brain. Here we show that hugin neuropeptide-containing neurons in the Drosophila larval brain are necessary for avoidance behaviour to caffeine, and when activated, result in cessation of feeding and mediates a bitter taste signal within the brain. Hugin neuropeptide-containing neurons project to the neurosecretory region of the protocerebrum and functional imaging demonstrates that these neurons are activated by bitter stimuli and by activation of bitter sensory receptor neurons. We propose that hugin neurons projecting to the protocerebrum act as gustatory interneurons relaying bitter taste information to higher brain centres in Drosophila larvae.
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http://dx.doi.org/10.1038/ncomms12796DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027282PMC
September 2016

Using stable isotopes to trace sources and formation processes of sulfate aerosols from Beijing, China.

Sci Rep 2016 07 20;6:29958. Epub 2016 Jul 20.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.

Particulate pollution from anthropogenic and natural sources is a severe problem in China. Sulfur and oxygen isotopes of aerosol sulfate (δ(34)Ssulfate and δ(18)Osulfate) and water-soluble ions in aerosols collected from 2012 to 2014 in Beijing are being utilized to identify their sources and assess seasonal trends. The mean δ(34)S value of aerosol sulfate is similar to that of coal from North China, indicating that coal combustion is a significant contributor to atmospheric sulfate. The δ(34)Ssulfate and δ(18)Osulfate values are positively correlated and display an obvious seasonality (high in winter and low in summer). Although an influence of meteorological conditions to this seasonality in isotopic composition cannot be ruled out, the isotopic evidence suggests that the observed seasonality reflects temporal variations in the two main contributions to Beijing aerosol sulfate, notably biogenic sulfur emissions in the summer and the increasing coal consumption in winter. Our results clearly reveal that a reduction in the use of fossil fuels and the application of desulfurization technology will be important for effectively reducing sulfur emissions to the Beijing atmosphere.
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http://dx.doi.org/10.1038/srep29958DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4951693PMC
July 2016

Effect of the pollution control measures on PM during the 2015 China Victory Day Parade: Implication from water-soluble ions and sulfur isotope.

Environ Pollut 2016 Nov 15;218:230-241. Epub 2016 Jul 15.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.

Air pollution by particulate matter is a serious problem in Beijing. Strict pollution control measures have been carried out in Beijing prior to and during the 2015 China Victory Day Parade in order to improve air quality. This distinct event provides an excellent opportunity for investigating the impact of such measures on the chemical properties of particulate matter with an aerodynamic diameter ≤2.5 μm (PM). The water-soluble ions as well as sulfur and oxygen isotopes of sulfate in PM collected between August 19 and September 18, 2015 (n = 31) were analyzed in order to trace the sources and formation processes of PM in Beijing. The results exhibit a decrease in concentration of water-soluble ions in PM including aerosol sulfate. In contrast, the mean values of δS (4.7 ± 0.8‰ vs. 5.0 ± 2.0‰) and δO (18.3 ± 2.3‰ vs. 17.2 ± 6.0) in PM during the air pollution control period and the non-source control period exhibit no significant differences, which suggests that despite a reduction in concentration, the sulfate source remains identical for the two periods. It is inferred that the decrease in concentration of sulfate in PM mainly results from variations in air mass transport. Notably, the air mass during the pollution control period originated mainly from north and northeast and changed to southerly directions thereafter. The sulfur and oxygen isotopes of the sulfate point to coal combustion as the major source of sulfate in PM from the Beijing area.
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http://dx.doi.org/10.1016/j.envpol.2016.06.038DOI Listing
November 2016

Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum.

Sci Rep 2016 Apr 14;6:24309. Epub 2016 Apr 14.

College of Applied Arts and Science of Beijing Union University, Beijing 100191, China.

Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ(114/110)Cdorgans-solution) of -0.70‰ to -0.22‰ in Ricinus communis and -0.51‰ to -0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology.
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http://dx.doi.org/10.1038/srep24309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4830953PMC
April 2016

Interaction between sulfur and lead in toxicity, iron plaque formation and lead accumulation in rice plant.

Ecotoxicol Environ Saf 2016 Jun 4;128:206-12. Epub 2016 Mar 4.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China.

Human activities have resulted in lead and sulfur accumulation in paddy soils in parts of southern China. A combined soil-sand pot experiment was conducted to investigate the influence of S supply on iron plaque formation and Pb accumulation in rice (Oryza sativa L.) under two Pb levels (0 and 600 mg kg(-1)), combined with four S concentrations (0, 30, 60, and 120 mg kg(-1)). Results showed that S supply significantly decreased Pb accumulation in straw and grains of rice. This result may be attributed to the enhancement of Fe plaque formation, decrease of Pb availability in soil, and increase of reduced glutathione (GSH) in rice leaves. Moderate S supply (30 mg kg(-1)) significantly increased Fe plaque formation on the root surface and in the rhizosphere, whereas excessive S supply (60 and 120 mg kg(-1)) significantly decreased the amounts of iron plaque on the root surface. Sulfur supply significantly enhanced the GSH contents in leaves of rice plants under Pb treatment. With excessive S application, the rice root acted as a more effective barrier to Pb accumulation compared with iron plaque. Excessive S supply may result in a higher monosulfide toxicity and decreased iron plaque formation on the root surface during flooded conditions. However, excessive S supply could effectively decrease Pb availability in soils and reduce Pb accumulation in rice plants.
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http://dx.doi.org/10.1016/j.ecoenv.2016.02.021DOI Listing
June 2016

Chemical and sulfur isotopic composition of precipitation in Beijing, China.

Environ Sci Pollut Res Int 2016 Mar 16;23(6):5507-15. Epub 2015 Nov 16.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.

China is experiencing serious acid rain contamination, with Beijing among the worst-hit areas. To understand the chemical feature and the origin of inorganic ions in precipitation of Beijing, 128 precipitation samples were collected and analyzed for major water-soluble ions and δ(34)S. The pH values ranged from 3.68 to 7.81 and showed a volume weighted average value (VWA) of 5.02, with a frequency of acid rain of 26.8 %. The VWA value of electrical conductivity (EC) was 68.6 μS/cm, which was nearly 4 times higher than the background value of northern China. Ca(2+) represented the main cation; SO4 (2-) and NO3 (-) were the dominant anion in precipitation. Our study showed that SO4 (2-) and NO3 (-) originated from coal and fossil fuel combustion; Ca(2+), Mg(2+), and K(+) were from the continental sources. The δ(34)S value of SO4 (2-) in precipitation ranged from +2.1 to +12.8‰ with an average value of +4.7‰. The δ(34)S value showed a winter maximum and a summer minimum tendency, which was mainly associated with temperature-dependent isotope equilibrium fractionation as well as combustion of coal with relatively positive δ(34)S values in winter. Moreover, the δ(34)S values revealed that atmospheric sulfur in Beijing are mainly correlated to coal burning and traffic emission; coal combustion constituted a significant fraction of the SO4 (2-) in winter precipitation.
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http://dx.doi.org/10.1007/s11356-015-5746-2DOI Listing
March 2016

Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets.

Proc Natl Acad Sci U S A 2014 Dec 1;111(50):17749-54. Epub 2014 Dec 1.

Department of Geology, University of Maryland, College Park, MD 20742; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742.

Achondrite meteorites have anomalous enrichments in (33)S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying (33)S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the (33)S anomalies, or of the bulk solar system S-isotope composition. Here, we report well-resolved anomalous (33)S depletions in IIIF iron meteorites (<-0.02 per mil), and (33)S enrichments in other magmatic iron meteorite groups. The (33)S depletions support the idea that differentiated planetesimals inherited sulfur that was photochemically derived from gases in the early inner solar system (<∼2 AU), and that bulk inner solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content.
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http://dx.doi.org/10.1073/pnas.1418907111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4273339PMC
December 2014

Cadmium accumulation and tolerance of two castor cultivars in relation to antioxidant systems.

J Environ Sci (China) 2014 Oct 10;26(10):2048-55. Epub 2014 Aug 10.

College of Applied Arts and Science of Beijing Union University, Beijing 100191, China.

To investigate the effects of Cd on tolerance and antioxidant activities of castor, two different castor (Ricinus communis L.) cultivars (Zibo No. 5 and Zibo No. 8) were used for a hydroponic experiment (0, 1 and 2mg/L Cd) and a pot experiment using Cd-contaminated soil (34mg/kg) with the addition of ethylenedinitrilotetraacetic acid (EDTA). The results indicated that there were significant differences between the two cultivars with respect to Cd uptake in shoots (113-248mg/kg for Zibo No. 5 and 130-288mg/kg Zibo No. 8), biomass tolerance indexes (64.9%-74.6% for Zibo No. 5 and 80.1%-90.9% for Zibo No. 8) in the hydroponic experiment and survival rates (0% for Zibo No. 5 and 100% for Zibo No. 8) determined by the addition of EDTA in the pot experiment, suggesting that Zibo No. 8 has higher tolerance than Zibo No. 5. Moreover, the castor cultivars have low bioconcentration factors (4.80% for Zibo No. 5 and 5.43% for Zibo No. 8) and low translocation factors (<1%). Consequently, Zibo No. 8 can participate in Cd phytostabilization in highly Cd-polluted areas. The results indicated that glutathione (GSH) as a non-enzymatic antioxidant, and antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX), were cultivar- and dose-dependent. The higher tolerance of Zibo No. 8 compared with Zibo No. 5 can be attributed to the higher GSH levels in the root and higher GPX activity in the leaf.
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http://dx.doi.org/10.1016/j.jes.2014.08.005DOI Listing
October 2014

Selection of motor programs for suppressing food intake and inducing locomotion in the Drosophila brain.

PLoS Biol 2014 Jun 24;12(6):e1001893. Epub 2014 Jun 24.

Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany.

Central mechanisms by which specific motor programs are selected to achieve meaningful behaviors are not well understood. Using electrophysiological recordings from pharyngeal nerves upon central activation of neurotransmitter-expressing cells, we show that distinct neuronal ensembles can regulate different feeding motor programs. In behavioral and electrophysiological experiments, activation of 20 neurons in the brain expressing the neuropeptide hugin, a homolog of mammalian neuromedin U, simultaneously suppressed the motor program for food intake while inducing the motor program for locomotion. Decreasing hugin neuropeptide levels in the neurons by RNAi prevented this action. Reducing the level of hugin neuronal activity alone did not have any effect on feeding or locomotion motor programs. Furthermore, use of promoter-specific constructs that labeled subsets of hugin neurons demonstrated that initiation of locomotion can be separated from modulation of its motor pattern. These results provide insights into a neural mechanism of how opposing motor programs can be selected in order to coordinate feeding and locomotive behaviors.
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http://dx.doi.org/10.1371/journal.pbio.1001893DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4068981PMC
June 2014

[Research on the effect and technique of remediation for multi-metal contaminated tailing soils].

Huan Jing Ke Xue 2013 Sep;34(9):3690-6

Center for Environmental Remediation, Institute of Geographical Sciences and Natural Resources, Chinese Academy of Sciences, Beijing 100101, China.

Soil samples were collected from compound polluted tailings to analyze the contents of total heavy metals and their speciation in the soil. Laboratory batch tests were conducted to examine the effects of distilled water and different concentrations of oxalic acid, citric acid, acetic acid, HNO3 and EDTA on the removal of heavy metals from the polluted soils. The suitable eluent and its optimal conditions including liquid to soil ratio, reaction time and washing number were also optimized, and the total toxicity reduction index was proposed to evaluate the effect of the eluent on the remediation of polluted soil. The results showed that Cd and Pb were the most abundant heavy metals in the soil, reaching 52.2 mg x kg(-1) and 4836.5 m x kg(-1), respectively. There was significant difference in the removal efficiency for different heavy metals. Cr had a maximum removal efficiency of 2.7%, while the maximum Cd and Pb removal efficiency was both about 60%. Distilled water had little removal efficiency for heavy metals, with less than 0.1% removal rate; the heavy metal removal efficiency of oxalic acid and acetic acid was also quite low; EDTA in 0.1 mol x L(-1) was selected as the suitable eluent for the polluted soil. Evaluation of the total toxicity reduction index and the cost suggested that EDTA should be used with a liquid to soil ratio of 6:1, a reaction time of 3 h and 2 washings.
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September 2013

Tracing the source of Beijing soil organic carbon: a carbon isotope approach.

Environ Pollut 2013 May 21;176:208-14. Epub 2013 Feb 21.

Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.

Bulk soil organic carbon concentration and isotopic composition characterize its sources and fate, identify the anthropogenic input of organic carbon into the soil, and trace soil carbon turnover. Coal and/or coal combustion products represent the prime anthropogenic input of organic carbon into three soil profiles located in the vicinity of a steel company. Three profiles positioned away from any direct industrial contribution display vertical pattern in soil organic carbon concentration and isotopic composition that resemble more commonly observed downward gradients in soil carbon chemistry and indicate microbial soil carbon turnover. Two additional profiles located outside of the immediate industrial area display vertical carbon isotope profiles between typical of those from industrial and non-industrial areas. Eight soil profiles and their vertical distribution of bulk organic carbon isotopic composition and concentration collected in the Beijing area reveal and distinguish both anthropogenic and natural contributions of carbon to these soils.
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http://dx.doi.org/10.1016/j.envpol.2013.01.035DOI Listing
May 2013

Bacterial sulfur cycling shapes microbial communities in surface sediments of an ultramafic hydrothermal vent field.

Environ Microbiol 2011 Oct 6;13(10):2633-48. Epub 2011 Sep 6.

Max Planck Institute for Marine Microbiology, Celsiusstr.1, D-28359 Bremen, Germany.

The ultramafic-hosted Logatchev hydrothermal field (LHF) is characterized by vent fluids, which are enriched in dissolved hydrogen and methane compared with fluids from basalt-hosted systems. Thick sediment layers in LHF are partly covered by characteristic white mats. In this study, these sediments were investigated in order to determine biogeochemical processes and key organisms relevant for primary production. Temperature profiling at two mat-covered sites showed a conductive heating of the sediments. Elemental sulfur was detected in the overlying mat and metal-sulfides in the upper sediment layer. Microprofiles revealed an intensive hydrogen sulfide flux from deeper sediment layers. Fluorescence in situ hybridization showed that filamentous and vibrioid, Arcobacter-related Epsilonproteobacteria dominated the overlying mats. This is in contrast to sulfidic sediments in basalt-hosted fields where mats of similar appearance are composed of large sulfur-oxidizing Gammaproteobacteria. Epsilonproteobacteria (7-21%) and Deltaproteobacteria (20-21%) were highly abundant in the surface sediment layer. The physiology of the closest cultivated relatives, revealed by comparative 16S rRNA sequence analysis, was characterized by the capability to metabolize sulfur components. High sulfate reduction rates as well as sulfide depleted in (34)S further confirmed the importance of the biogeochemical sulfur cycle. In contrast, methane was found to be of minor relevance for microbial life in mat-covered surface sediments. Our data indicate that in conductively heated surface sediments microbial sulfur cycling is the driving force for bacterial biomass production although ultramafic-hosted systems are characterized by fluids with high levels of dissolved methane and hydrogen.
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http://dx.doi.org/10.1111/j.1462-2920.2011.02530.xDOI Listing
October 2011

Isotopic evidence for Mesoarchaean anoxia and changing atmospheric sulphur chemistry.

Nature 2007 Oct;449(7163):706-9

Department of Geology and ESSIC, University of Maryland, College Park, Maryland 20742, USA.

The evolution of the Earth's atmosphere is marked by a transition from an early atmosphere with very low oxygen content to one with an oxygen content within a few per cent of the present atmospheric level. Placing time constraints on this transition is of interest because it identifies the time when oxidative weathering became efficient, when ocean chemistry was transformed by delivery of oxygen and sulphate, and when a large part of Earth's ecology changed from anaerobic to aerobic. The observation of non-mass-dependent sulphur isotope ratios in sedimentary rocks more than approximately 2.45 billion years (2.45 Gyr) old and the disappearance of this signal in younger sediments is taken as one of the strongest lines of evidence for the transition from an anoxic to an oxic atmosphere around 2.45 Gyr ago. Detailed examination of the sulphur isotope record before 2.45 Gyr ago also reveals early and late periods of large amplitude non-mass-dependent signals bracketing an intervening period when the signal was attenuated. Until recently, this record has been too sparse to allow interpretation, but collection of new data has prompted some workers to argue that the Mesoarchaean interval (3.2-2.8 Gyr ago) lacks a non-mass-dependent signal, and records the effects of earlier and possibly permanent oxygenation of the Earth's atmosphere. Here we focus on the Mesoarchaean interval, and demonstrate preservation of a non-mass-dependent signal that differs from that of preceding and following periods in the Archaean. Our findings point to the persistence of an anoxic early atmosphere, and identify variability within the isotope record that suggests changes in pre-2.45-Gyr-ago atmospheric pathways for non-mass-dependent chemistry and in the ultraviolet transparency of an evolving early atmosphere.
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http://dx.doi.org/10.1038/nature06202DOI Listing
October 2007

Microbial CO(2) fixation and sulfur cycling associated with low-temperature emissions at the Lilliput hydrothermal field, southern Mid-Atlantic Ridge (9 degrees S).

Environ Microbiol 2007 May;9(5):1186-201

Leibniz Institute of Marine Sciences (IFM-GEOMAR), Marine Microbiology, Düsternbrooker Weg 20, D-24105 Kiel, Germany.

Lilliput was discovered in 2005 as the southernmost known hydrothermal field along the Mid-Atlantic Ridge. It is exceptional in that it lacks high-temperature venting probably because of a thickened crust. The absence of thermophilic and hyperthermophilic prokaryotes in emissions supports the argument against the presence of a hot subsurface at Lilliput, as is typically suggested for diffuse emissions from areas of high-temperature venting. The high phylogenetic diversity and novelty of bacteria observed could be because of the low-temperature influence, the distinct location of the hydrothermal field or the Bathymodiolus assemblages covering the sites of discharge. The low-temperature fluids at the Lilliput are characterized by lowered pH and slightly elevated hydrogen (16 nM) and methane ( approximately 2.6 microM) contents compared with ambient seawater. No typical hydrogen and methane oxidizing prokaryotes were detected. The higher diversity of reverse tricarboxylic acid genes and the form II RubisCO genes of the Calvin Benson-Bassham (CBB) cycle compared with the form I RubisCO genes of the CBB cycle suggests that the chemoautotrophic community is better adapted to low oxygen concentrations. Thiomicrospira spp. and Epsilonproteobacteria dominated the autotrophic community. Sulfide is the most abundant inorganic energy source (0.5 mM). Diverse bacteria were associated with sulfur cycling, including Gamma-, Delta- and Epsilonproteobacteria, with the latter being the most abundant bacteria according to fluorescence in situ hybridization. With members of various Candidate Divisions constituting for 25% of clone library sequences we suggest that their role in vent ecosystems might be more important than previously assumed and propose potential mechanisms they might be involved in at the Lilliput hydrothermal field.
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http://dx.doi.org/10.1111/j.1462-2920.2007.01241.xDOI Listing
May 2007