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Isotope Techniques in Flood Analysis
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Samir Al-Gamal, Saeid Eslamian
where R denotes the ratio of the heavy to light isotope (e.g., 34S/32S), and Rx and Rs are the ratios in the sample and standard, respectively. For sulfur, carbon, nitrogen, and oxygen, the average terrestrial abundance ratio of the heavy to the light isotope ranges from 1:22 (sulfur) to 1:500 (oxygen); the ratio 2H:1H is much lower at 1:6,410. A positive d value means that the isotopic ratio of the sample is higher than that of the standard; a negative d value means that the isotopic ratio of the sample is lower than that of the standard. For example, a δ15N value of +30‰ means that the 15N/14N of the sample is 30 partsperthousand or 3% higher than the 15N/14N of the standard. Many isotope geochemists advocate always prefacing the d value with a sign, even when the value is positive; to distinguish between a true positive d value and a d value that is merely missing its sign (a frequent occurrence with users unfamiliar with isotope terminology). There are several commonly used ways for making comparisons between the d values of two materials. The first two are preferred because of their clarity, and the fourth should be avoided: High vs. low values.More/less positive vs. more/less negative (e.g., −10‰ is more positive than −20‰.Heavier vs. lighter (the “heavy” material is the one with the higher δ value).Enriched vs. depleted (always remember to state what isotope is in short supply) e.g., a material is enriched in δ18O or δ16O relative to some other material, and that theenrichment or depletion is a result of some reaction or process). For example, to say that “one sample is enriched in δ34S relative to another because of sulfate reduction” is the proper usage. Phrases such as “a sample has an enriched δ15N value” are misuses oftheterminology.
The Use of Stable Isotopic Analyses to Identify Pulp Mill Effluent Signatures in Riverine Food Webs
Published in Mark R. Servos, Kelly R. Munkittrick, John H. Carey, Glen J. Van Der Kraak, and PAPER MILL EFFLUENTS, 2020
Leonard I. Wassenaar, Joseph M. Culp
Riverine food webs are supported by energy flow from allochthonous detritus and autochthonous primary production (Vannote et al. 1980), and consumers of this plant tissue should have an isotopic signature approximately 2.5-3.5‰ higher than the primary producer trophic level (Minagawa and Wada 1984; Fry 1991). In the Thompson River, the δ15N values of the algal biofilm (0.8 to 3.8‰), chironomidae (1.8-2.2‰) and mayflies (3.2-4.8‰) were similar, suggesting that none of the insect consumers feed solely on algal biofilm (Table 2; Fig. 2). At the Walhachin site, the only location where biofilm and insect consumers where sampled simultaneously, mayfly δ15N values were 0.5-2.0‰ higher than the biofilm. In contrast, chironomid δ15N values (2.2‰) were depleted relative to algal biofilm (2.7‰). Thus, both mayflies and chironomids appear to consume algal biofilm and an unmeasured, isotopically depleted nitrogen source. This unknown source could be POM (δ15N of 0-l‰) imported from upstream headwaters, or DOM in the PME. As with carbon, a simple two-component nitrogen isotope mass balance was constructed to estimate relative proportions. The δ15N values of terrestrial organic matter commonly range between 0 and 1‰. Assuming an average insect δ15N of +4‰, an average biofilm δ15N of 3.5‰ and a single trophic level fractionation of 3.5‰, ()δ15Ninsects=[X(δ15Nbiofilm)+Y(δ15Nterrestrial)]+3.5trophicfractiontion
Stable 15N isotopes in fine and coarse urban particulate matter
Published in Aerosol Science and Technology, 2021
Hanna Wiedenhaus, Laura Ehrnsperger, Otto Klemm, Harald Strauss
Total nitrogen isotope analyses (δ15N-TN) were carried out in the Stable Isotope Laboratory at the Institute of Geology and Paleontology using a Flash EA IsoLink interfaced to a ThermoScientific Delta V Advantage mass spectrometer (EA-IRMS). The samples from the ELPI + collected on tin foil were used for these analyses. From each set, samples of ten stages and one blank were selected, considering sufficient particle mass concentration and ion concentration on the respective stage. The clean edge of each tin foil piece was first cut off with precision scissors, then the remaining foil containing the sample was folded and subjected to direct combustion in a single reactor packed with tungsten oxide and copper wire. Combustion temperature was set at 1020 °C. The blank samples were treated in the same way. Evolved gases were separated chromatographically in the order nitrogen (N2), then carbon dioxide (CO2) and finally sulfur dioxide (SO2) and measured without further dilution. Results are reported in the standard delta notation as per mil difference from the international reference standard AIR for nitrogen isotopes:
Hydrochemical and stable isotopes indicators for detecting sources of groundwater contamination close to Bahr El-Baqar drain, eastern Nile Delta, Egypt
Published in Water Science, 2019
Mustafa Eissa, Mohamed Ali, Ehab Zaghlool, Orfan Shouakar Stash
Where the concentrations of total cations and total anions are represented in milliequivalent per liter. To confirm the water the quality assurance, the acceptable range for (E.B., %) is within ±2%. The Environmental stable isotopes (δ18O, δ2H, and δ15N) were carried out at the IT2 laboratory in Waterloo, Canada (Table 2). The δ18O and δ2H samples were carried out using Cavity Ring-Down Spectroscopy the CRDS Model L2130-i, Picarro. The standard used was IT2-10B/IT2-13A/IT2-00 Calibrated with IAEA Standards (V-SMOW, SLAP, and GISP). The δ15N samples were carried out using Delta Plus Isotope Ratio Mass Spectrometry (IRMS), Finnegan MAT, Germany, coupled with an Elemental Analyzer EA 1110 CHN, CE Instruments, Italy stander used was IT2-601/IAEA-N1/IAEA-N2/Acetanilide (B-2000).
Using a nitrogen and oxygen isotopic approach to identify nitrate sources and cycling in the Wei River of northwestern China
Published in Human and Ecological Risk Assessment: An International Journal, 2019
Jing Hu, Weiguo Liu, Meng Xing, Yuliang Li
Part 3 includes the main stream of the Wei River, with NO3−-N concentrations from 5 to 10 mg/L and δ15N-NO3− values greater than 8‰ (Figures 3 and 5). The main stream flows through populated areas including the city of Tianshui in Gansu Province, and the cities of Baoji, Xianyang, Xi'an, and Weinan in Shannxi Province. The high δ15N- NO3− values indicate sewage sources (Kendall 1998).