Finding the Information of the Unknown DNAPL Residual Source using various tracer data, Wonju, Korea

Author(s):  
Seong-Sun Lee ◽  
Il-Ryoung Cho ◽  
Yeojin Ju ◽  
Kang-Kun Lee

<p>In this study, analytical solution method which can evaluate and quantify the impacts of partial mass reduction by remedial action performed in study site is applied to estimate the unknown DNAPL source mass and dissolved concentration using long-term monitoring data collected from 2009 to 2019. Also, noble gas tracer method was applied to identify the partitioning processes which can be happened in TCE contaminated site. By using the source zone monitoring data during about 10 years and analytical solution, initial dissolved concentration and residual mass of TCE in spilled period at the main source zone were roughly estimated 150 mg/L and 1000 kg, respectively. These values decreased to 0.45 mg/L and 33.07 kg direct after an intensive remedial action performed in 2013 and then it expected to be continuously decreased to 0.29 mg/L and 25.41 kg from the end of remedial actions to 2020. From results of quantitative evaluation using analytical solution, it can be evaluated that the intensive remedial action had effectively performed with removal efficiency of 70% for the residual source mass during the remediation period. From the results of noble gas analysis, the distance from TCE source zone was divided into three groups from Zone 1 to 3. Zone 1 includes samples that are the closest from the TCE main source, and are highly partitioned to TCE compared to other zones. Zone 3 samples show least accordance with either of the fractionation lines, showing that sampling points are influenced highly by other mechanism rather than partitioning to TCE. Also, it is identified that seasonal variation of groundwater level can be affected to the distribution of noble gas at around TCE source zone. Samples from only “High TCE” zone are plotted along with ideal batch equilibrium and Rayleigh fractionation line again and divided into two groups according to their sampling date. From August 2018 to October, 2018, samples shift from right to left in the figure, getting closer to Rayleigh fractionation line. In August, noble gas was relatively in equilibrium between groundwater and TCE. However, as water table rises, noble gas became touch with residual TCE locating above the previous water-level, which is a receiving fluid in water-TCE system. Results of this study was support that it was able to estimate the unknown quantitative information for TCE contamination and noble gas as the indicator of DNAPL contamination could be applied in allocating the DNAPL source which is relatively hard to estimate.</p>

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3327
Author(s):  
Martina Mattia ◽  
Paola Tuccimei ◽  
Michele Soligo ◽  
Claudio Carusi

In this research, the radioactive noble gas radon was used as a tracer for Non-Aqueous Phase Liquids (NAPLs) contamination, since it is much more soluble in these substances than in air or water. Soil radon remains trapped within the NAPLs, resulting in a local reduction in the radon concentration within close proximity to the contaminated area. This technique was applied to a contaminated site in Roma (Italy). The main residual NAPLs are total hydrocarbons and methyl-tertiary-butyl ether (MTBE), a water-soluble additive. The monitoring activities included two sampling campaigns of groundwater from 18 wells in February and May 2020. Concentration maps were produced using radon data. The results show that the radon deficit traces the location of NAPLs in the fuelling station very well, with a residual source zone extending in a NNW-SSE direction. A good correspondence between a low amount of radon and a higher concentration of NAPLs was found. A reduction in the average amount of radon in the May 2020 survey indicated a stronger remobilization of NAPLs compared to that of the February 2020 monitoring campaign. The peaks of Volatile Organic Compounds (VOCs) detected between 8–9 and 11–12 m depths indicate the presence of residual blobs of NAPLs in the vadose zone of the aquifer.


2011 ◽  
Vol 63 (10) ◽  
pp. 1097-1111 ◽  
Author(s):  
Ken-ichi Bajo ◽  
Tomohiro Akaida ◽  
Noriaki Ohashi ◽  
Takaaki Noguchi ◽  
Tomoki Nakamura ◽  
...  

2017 ◽  
Vol 156 (1) ◽  
pp. 1-24
Author(s):  
GORO KOMATSU ◽  
JENS ORMÖ ◽  
TOGOOKHUU BAYARAA ◽  
TOMOKO ARAI ◽  
KEISUKE NAGAO ◽  
...  

AbstractThe Tsenkher structure in the Gobi-Altai, Mongolia is a c. 3.7 km diameter crater with a well-preserved ejecta blanket. It has been hypothesized to be either of impact or volcanic origin in our previous work. Observations during our 2007 expedition and related sample analyses give further support for an impact origin. The evidence includes the presence of a structurally uplifted near-circular rim surrounded by an ejecta blanket, and abundant breccias, some of which are melt- and millimetre-scale spherule-bearing. Planar deformation features (PDFs) were found in one quartz grain in a breccia sample. Fe-rich grains are found in a vesicular melt sample that is also characterized by elevated platinum group element (PGE) abundances with respect to the sedimentary bedrock of the area (approximately an order of magnitude). Noble gas analysis of one breccia sample yielded an elevated 3He/4He value of (5.0±0.2) × 10−6. Although not conclusive alone, these geochemical results are consistent with a contribution of meteoritic components. A volcanic origin, in particular a maar formation, would require explanations for the unusual conditions associated with Tsenkher, including its large size occurring in isolation, the structurally uplifted rim and the lack of a bedded base surge deposit. A pronounced rampart structure observed at the eastern ejecta is also unusual for any volcanic origin. 40Ar–39Ar dating of a vesicular melt sample gives an age of the Tsenkher structure of 4.9±0.9 Ma. The rampart structure could provide insights into the formation of similar ejecta morphologies associated with numerous impact craters on Mars.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5824
Author(s):  
Natasha Trujillo ◽  
Dylan Rose-Coss ◽  
Jason E. Heath ◽  
Thomas A. Dewers ◽  
William Ampomah ◽  
...  

Leakage pathways through caprock lithologies for underground storage of CO2 and/or enhanced oil recovery (EOR) include intrusion into nano-pore mudstones, flow within fractures and faults, and larger-scale sedimentary heterogeneity (e.g., stacked channel deposits). To assess multiscale sealing integrity of the caprock system that overlies the Morrow B sandstone reservoir, Farnsworth Unit (FWU), Texas, USA, we combine pore-to-core observations, laboratory testing, well logging results, and noble gas analysis. A cluster analysis combining gamma ray, compressional slowness, and other logs was combined with caliper responses and triaxial rock mechanics testing to define eleven lithologic classes across the upper Morrow shale and Thirteen Finger limestone caprock units, with estimations of dynamic elastic moduli and fracture breakdown pressures (minimum horizontal stress gradients) for each class. Mercury porosimetry determinations of CO2 column heights in sealing formations yield values exceeding reservoir height. Noble gas profiles provide a “geologic time-integrated” assessment of fluid flow across the reservoir-caprock system, with Morrow B reservoir measurements consistent with decades-long EOR water-flooding, and upper Morrow shale and lower Thirteen Finger limestone values being consistent with long-term geohydrologic isolation. Together, these data suggest an excellent sealing capacity for the FWU and provide limits for injection pressure increases accompanying carbon storage activities.


2021 ◽  
Author(s):  
Karl Haase ◽  
Morgan Wallace ◽  
Gerolamo Casile ◽  
Tyler Coplen
Keyword(s):  

2013 ◽  
Vol 18 (6) ◽  
pp. 8-17 ◽  
Author(s):  
Seong-Sun Lee ◽  
Hun-Mi Kim ◽  
Seung Hyun Lee ◽  
Jae-Ha Yang ◽  
Youn Eun Koh ◽  
...  

2013 ◽  
Vol 34 ◽  
pp. 90-101 ◽  
Author(s):  
Francesca Giustini ◽  
Michaela Blessing ◽  
Mauro Brilli ◽  
Salvatore Lombardi ◽  
Nunzia Voltattorni ◽  
...  

2020 ◽  
Author(s):  
Andrea L. Popp ◽  
Álvaro Pardo-Álvarez ◽  
Oliver S. Schilling ◽  
Stéphanie Musy ◽  
Andreas Scheidegger ◽  
...  

<p class="western"><span lang="en-US">The quality and quantity of alluvial groundwater in mountainous areas are particularly susceptible to the effects of climate change, as well as increasing pollution from agriculture and urbanization. Understanding mixing between surface water and groundwater as well as groundwater travel times in such systems is thus crucial to sustain a safe and sufficient water supply. We used a novel combination of real-time, in-situ noble gas analysis to quantify groundwater mixing of recently infiltrated river water (<em>F<sub>rw</sub></em><!-- Please note that everything in “$$” will look differently once submitted -->) and regional groundwater, as well as travel times of <em>F<sub>rw</sub></em> during a two-month groundwater pumping test carried out at a drinking water wellfield in a prealpine valley in Switzerland. Transient groundwater mixing ratios were calculated using helium-4 concentrations combined with a Bayesian end-member mixing model. Having identified the groundwater fraction of <em>F<sub>rw</sub></em> consequently allowed us to infer the travel times from the stream to the wellfield, estimated based on radon-222 activities of <em>F<sub>rw</sub></em>. Additionally, we compared and validated our tracer-based estimates of <em>F<sub>rw</sub></em> using a calibrated surface water-groundwater model. Our findings show that (i) mean travel times of <em>F<sub>rw</sub></em> are in the order of two weeks, (ii) during most of the experiment, <em>F<sub>rw</sub></em> is substantially high (~70\%), and (iii) increased groundwater pumping only has a marginal effect on groundwater mixing ratios and travel times. The high fraction of <em>F<sub>rw</sub></em> in the abstracted groundwater and its short travel times emphasize the vulnerability of mountainous regions to present and predicted environmental changes.</span></p>


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