Controlled induction of denitrification in Pseudomonas aureofaciens: A simplified denitrifier method for dual isotope analysis in NO3−

Abstract Two-dimensional compound specific isotope analysis has become a powerful tool to distinguish reaction mechanism. Lambda (Λ), an essential and important parameter for processing two-dimensional isotope fractionation data, is specific to a reaction mechanism. In the present article, we modified the existing algorithms for Lambdas based on the review of the current methods. Specifically, through regressing [(1000+δE0,2)*(n1*x2)*ΔδEbulk,1] versus [(1000+δE0,1)*(n2*x1)*ΔδEbulk,2] by York method, a novel method was developed to calculate Λs. The improved method eliminates both the influence of non-reacting position and the initial isotope signatures. Furthermore, this method retains the advantages of two-dimension isotope plot, which eliminates contributions from commitment to catalysis, no need to determine fraction of remaining substrate and can be constructed even from filed data. At the same time, one sample t test is applied to generate 95% confidence interval of data set of Λris for various reaction mechanisms. The range of 5.67-24.8, 8.54-9.80, 0.51-8.35, 25.2-36.8, 7.09-21.9 are responsible for oxidation of C-H bonds (ZC=1, ZH=3), oxidation of C-H bonds (ZC=1,ZH=4), aerobic biodegradation of benzene (ZC=6,ZH=6), methanogenic or sulfate-reducing biodegradation of benzene (ZC=6,ZH=6), and nitrate-reducing biodegradation of benzene (ZC=6,ZH=6). The accumulation and correction of these values will make the data measured in the field easier to interpret.

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Stable Isotopes of Water and Nitrate for the Identification of Groundwater Flowpaths: A Review

Water ◽

10.3390/w12010138 ◽

2020 ◽

Vol 12 (1) ◽

pp. 138 ◽

Cited By ~ 6

Author(s):

Hyejung Jung ◽

Dong-Chan Koh ◽

Yun Kim ◽

Sung-Wook Jeen ◽

Jeonghoon Lee

Keyword(s):

Stream Water ◽

Isotope Analysis ◽

Nitrate Contamination ◽

Hydrograph Separation ◽

Nitrate Sources ◽

Dual Isotope ◽

Contaminant Sources ◽

The Difference ◽

Stable Isotopes Of Water ◽

Groundwater Flowpaths

Nitrate contamination in stream water and groundwater is a serious environmental problem that arises in areas of high agricultural activities or high population density. It is therefore important to identify the source and flowpath of nitrate in water bodies. In recent decades, the dual isotope analysis (δ15N and δ18O) of nitrate has been widely applied to track contamination sources by taking advantage of the difference in nitrogen and oxygen isotope ratios for different sources. However, transformation processes of nitrogen compounds can change the isotopic composition of nitrate due to the various redox processes in the environment, which often makes it difficult to identify contaminant sources. To compensate for this, the stable water isotope of the H2O itself can be used to interpret the complex hydrological and hydrochemical processes for the movement of nitrate contaminants. Therefore, the present study aims at understanding the fundamental background of stable water and nitrate isotope analysis, including isotope fractionation, analytical methods such as nitrate concentration from samples, instrumentation, and the typical ranges of δ15N and δ18O from various nitrate sources. In addition, we discuss hydrograph separation using the oxygen and hydrogen isotopes of water in combination with the nitrogen and oxygen isotopes of nitrate to understand the relative contributions of precipitation and groundwater to stream water. This study will assist in understanding the groundwater flowpaths as well as tracking the sources of nitrate contamination using the stable isotope analysis in combination with nitrate and water.

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Use of C–Cl CSIA to elucidate origin and fate of DCM in complex contaminated field sites

E3S Web of Conferences ◽

10.1051/e3sconf/20199812003 ◽

2019 ◽

Vol 98 ◽

pp. 12003

Author(s):

Natàlia Blázquez-Pallí ◽

Orfan Shouakar-Stash ◽

Jordi Palau ◽

Alba Trueba-Santiso ◽

Joan Varias ◽

...

Keyword(s):

Field Data ◽

Enrichment Culture ◽

Isotope Analysis ◽

Data Interpretation ◽

Dual Isotope ◽

Isotopic Compositions ◽

The Common ◽

Microcosm Studies ◽

Groundwater Pollutant ◽

Contaminated Field

We used C-Cl dual isotope analysis and microcosm studies for elucidating the origin and fate of the common groundwater pollutant dichloromethane (DCM) in two different multi-contaminant field sites in Catalonia, Spain; where DCM contamination could be the result of direct solvent releases and/or chloroform (CF) transformation. Known commercial solvents isotopic compositions as well as characteristic C-Cl dual isotope slopes from our anaerobic enrichment culture containing Dehalobacterium sp., capable of fermenting DCM, and other bacteria from the literature were used for field data interpretation.

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Rayleigh-Based Concept to Tackle Strong Hydrogen Fractionation in Dual Isotope Analysis—The Example of Ethylbenzene Degradation by Aromatoleum aromaticum

Environmental Science & Technology ◽

10.1021/es404837g ◽

2014 ◽

Vol 48 (10) ◽

pp. 5788-5797 ◽

Cited By ~ 16

Author(s):

Conrad Dorer ◽

Patrick Höhener ◽

Normen Hedwig ◽

Hans-Hermann Richnow ◽

Carsten Vogt

Keyword(s):

Isotope Analysis ◽

Dual Isotope

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Triple Oxygen Isotope Analysis of Nitrate Using the Denitrifier Method and Thermal Decomposition of N2O

Analytical Chemistry ◽

10.1021/ac061022s ◽

2007 ◽

Vol 79 (2) ◽

pp. 599-607 ◽

Cited By ~ 152

Author(s):

Jan Kaiser ◽

Meredith G. Hastings ◽

Benjamin Z. Houlton ◽

Thomas Röckmann ◽

Daniel M. Sigman

Keyword(s):

Thermal Decomposition ◽

Oxygen Isotope ◽

Isotope Analysis ◽

Denitrifier Method

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Evaluation of wastewater nitrogen transformation in a natural wetland (Ulaanbaatar, Mongolia) using dual-isotope analysis of nitrate

The Science of The Total Environment ◽

10.1016/j.scitotenv.2011.01.019 ◽

2011 ◽

Vol 409 (8) ◽

pp. 1530-1538 ◽

Cited By ~ 25

Author(s):

Masayuki Itoh ◽

Yasuhiro Takemon ◽

Akiko Makabe ◽

Chikage Yoshimizu ◽

Ayato Kohzu ◽

...

Keyword(s):

Isotope Analysis ◽

Nitrogen Transformation ◽

Natural Wetland ◽

Dual Isotope

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Assessing Seasonal Nitrate Contamination by Nitrate Dual Isotopes in a Monsoon-Controlled Bay with Intensive Human Activities in South China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17061921 ◽

2020 ◽

Vol 17 (6) ◽

pp. 1921

Author(s):

Jiacheng Li ◽

Ruixue Cao ◽

Qibin Lao ◽

Fajin Chen ◽

Chunqing Chen ◽

...

Keyword(s):

River Basin ◽

South China ◽

Human Activities ◽

Isotope Analysis ◽

N Fertilizer ◽

Nitrate Contamination ◽

Local Source ◽

Biological Processes ◽

Soil N ◽

Dual Isotope

Nitrate (NO3−) dual isotope analysis was performed in Zhanjiang Bay, which is a closed bay with intensive human activities in South China, to investigate seasonal changes in the main NO3− sources and their biogeochemical processes in the monsoon-controlled climate. The relatively low N/P ratios in Zhanjiang Bay suggests that nitrogen (N) is a limiting nutrient, which indicates that the increase of N is favorable for phytoplankton proliferation. However, a sufficient amount of ammonium was found in our study area owing to intensive human activities, which can support biological processes. Thus, less NO3− biological processes were found, indicating that NO3− isotopic characteristics may reveal details of the mixing from various sources. The Bayesian mixing model showed that NO3− in the upper bay originated from manure (43%), soil N (30%), N fertilizer (17%), and N precipitation (10%) during winter, which reflects the local human activities; while NO3- sources during summer were mainly N fertilizer (36%), soil N (32%), and manure (31%), indicating the source as the runoff from the upper river basin. Our results suggest that nitrate dual-isotope was very useful for tracing the main NO3− sources in the condition of the sufficient ammonium, and runoff exerted an important impact on the shift in NO3− sources between both the local source and the source from the upper river basin during the two seasons in this monsoon-controlled bay.

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Quantifying the contribution of three competing pathways to total degradation in groundwater by a triple-isotope analysis approach

10.5194/egusphere-egu2020-14776 ◽

2020 ◽

Author(s):

Martin Thullner ◽

Florian Centler ◽

Thomas Hofstetter

Keyword(s):

Stable Isotope ◽

Isotope Fractionation ◽

Environmental Science ◽

Isotope Analysis ◽

Enrichment Factors ◽

Theoretical Concept ◽

Degradation Pathways ◽

Theoretical Concepts ◽

Dual Isotope ◽

Stable Isotope Fractionation

In groundwater and other environmental compartments, compound-specific stable isotope analysis (CSIA) has been used for the determination of specific degradation pathways by analyzing the stable isotopes of two elements. This &#8216;dual-isotope&#8217; or two-dimensional isotope&#8217; analysis also allows for an estimation of the contribution of two different pathways contributing both to the overall degradation and stable isotope fractionation. Heterogeneous groundwater flow patterns lead to some yet acceptable uncertainities in the results of this method. &#160;Recent CSIA approaches also allow for investigating the simultaneous stable isotope fractionation effects for three different elements. Such information on the stable isotope fractionation of three different elements of a degradable compound could be used for a quantitative analysis of the contribution of different degradation pathways in systems with three different pathways, but up to know there is no theoretical concepts providing such quantitative estimate.The aim of the present study is to overcome this shortage and to present such theoretical concept for the quantification of single pathway contribution to the overall biodegradation in groundwater and other systems with three parallel degradation pathways. For this purpose the approach of Centler et al. (2013) for the analysis of dual-isotope analysis has been expanded to consider the fractionation of three different elements affected by three different pathways. The obtained analytical expression allows for the quantification of each pathway to total degradation based stable isotope enrichment factors and measured stable isotope signatures. The applicability of the concept is demonstrated using data from Wijker et al. (2013).&#160;Centler, F., Hesse, F., and Thullner, M. (2013) Journal of Contaminant Hydrology, 152, 97-116.Wijker, R. S., Bolotin, J., Nishino, S. F., Spain, J. C., and Hofstetter, T. B. (2013) Environmental Science & Technology, 47, 6872-6883.&#160;

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Laboratory Experiments to Evaluate the Effectiveness of Persulfate to Oxidize BTEX in Saline Environment and at Elevated Temperature Using Stable Isotopes

Hydrology ◽

10.3390/hydrology8030139 ◽

2021 ◽

Vol 8 (3) ◽

pp. 139

Author(s):

Waleed Saeed ◽

Orfan Shouakar-Stash ◽

Jim Barker ◽

Neil Thomson ◽

Rick McGregor

Keyword(s):

Middle Eastern ◽

Isotope Analysis ◽

High Water ◽

Chemical Oxidation ◽

Saline Environment ◽

Dual Isotope ◽

Contaminant Degradation ◽

Groundwater Aquifers ◽

System Temperature ◽

Benzene Toluene

In this study, batch experiments were carried out to investigate the effectiveness of persulfate (PS) as an oxidant agent to remediate benzene, toluene, ethylbenzene, and xylenes (BTEX) in saline environments and at high water temperatures (30°C). This hydrological setting is quite common in contaminated groundwater aquifers in Middle Eastern countries. In general, increasing the system temperature from 10 to 30°C greatly enhanced the effectiveness of PS, and resulted in a faster oxidation rate for the target contaminants. When PS was added to the reactor at 30 °C, the targeted contaminants were almost completely oxidized over a 98-day reaction period. During the chemical oxidation of the BTEX, carbon and hydrogen isotope fractionations were monitored and utilized as potential proof of contaminant degradation. The calculated carbon-enrichment values were −1.9‰ for benzene, −1.5‰ for ethylbenzene and toluene, −0.4‰ for ρ,m-xylene, and -1.4‰ for o-xylene, while the hydrogen enrichment values were −9.5‰, -6.8‰, −2.1‰, −6.9‰, and −9.1‰, respectively. In comparison with other processes, the hydrogen and carbon isotope fractionations during the chemical oxidation by PS were smaller than the isotope fractionations resulting from sulfate reduction and denitrification. This observation demonstrates the differences in the transformation pathways and isotope fractionations when compounds undergo chemical oxidation or biodegradation. The distinct trend observed on the dual isotope plot (Δδ13C vs. Δδ2H) suggests that compound-specific isotope analysis can be utilized to monitor the chemical oxidation of BTEX by PS, and to distinguish treatment zones where PS and biodegradation technologies are applied simultaneously.

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