Impact of drilling mud on chemistry and microbiology of an Upper Triassic groundwater after drilling and testing an exploration well for aquifer thermal energy storage in Berlin (Germany)     

Simona Regenspurg  Mashal Alawi  Guido Blöcher  Maria Börger  Stefan Kranz  Ben Norden  Ali Saadat  Traugott Scheytt  Lioba Virchow  Andrea Vieth-Hillebrand 《Environmental Earth Sciences》2018,77(13):516

After completion of an exploration well, sandstones of the Exter Formation were hydraulically tested to determine the hydraulic properties and to evaluate chemical and microbial processes caused by drilling and water production. The aim was to determine the suitability of the formation as a reservoir for aquifer thermal energy storage. The tests revealed a hydraulic conductivity of 1–2 E-5 m/s of the reservoir, resulting in a productivity index of 0.6–1 m³/h/bar. A hydraulic connection of the Exter Formation to the overlaying, artesian “Rupelbasissand” cannot be excluded. Water samples were collected for chemical and microbiological analyses. The water was similarly composed as sea water with a maximum salinity of 24.9 g/L, dominated by NaCl (15.6 g/L Cl and 7.8 g/L Na). Until the end of the tests, the water was affected by drilling mud as indicated by the high pH (8.9) and high bicarbonate concentration (359 mg/L) that both resulted from the impact of sodium carbonate (Na₂CO₃) additives. The high amount of dissolved organic matter (>?58 mg/L) and its molecular-weight distribution pattern indicated that residues of cellulose, an ingredient of the drilling mud, were still present at the end of the tests. Clear evidence of this contamination gave the measured uranine that was added as a tracer into the drilling mud. During fluid production, the microbial community structure and abundance changed and correlated with the content of drilling mud. Eight taxa of sulfate-reducing bacteria, key organisms in processes like bio-corrosion and bio-clogging, were identified. It can be assumed that their activity will be affected during usage of the reservoir.  相似文献   

Toxic metals in a highly urbanized industry-impacted estuary (Bahia Blanca Estuary,Argentina): spatio-temporal analysis based on GIS     

Melisa Daiana Fernández Severini  María Elizabeth Carbone  Diana Mariel Villagran  Jorge Eduardo Marcovecchio 《Environmental Earth Sciences》2018,77(10):393

Cadmium, chromium, nickel, and lead were evaluated in the particulate fraction at one of the most industrialized estuaries at the Southwestern Atlantic Ocean, through Geographic Information System (GIS). Concentrations were analyzed at 21 stations during 2008–2010. The highest metal concentrations (Cd: 8,9; Cr: 256,49; Ni: 27,02; Pb: 78,43 µg g^??1 d. w.) were recorded at the stations located near industrial and urban discharges situated along the estuary. In addition, Pb presented a different seasonal and spatial behavior in comparison with Cd, Cr and Ni. Winter and spring presented the higher concentrations of Pb, and the inner stations presented the higher values. The estuary is considered a moderate to strongly polluted and significantly polluted according to the Index of geoaccumulation (I_geo) and the Enrichment Factor of Cd, respectively. The Multidimensional Scaling plot showed three groups of stations: the inner, associated to low levels of metals (G1), middle stations (G2) with intermediate levels and the outer (G3) with the highest ones. In addition, this work reveals the usefulness of the GIS-mapping techniques in the distribution of pollutants along an estuarine environment and the environmental quality assessment of estuarine systems.  相似文献   

Spatial and temporal analyses of air pollutants and meteorological driving forces in Beijing–Tianjin–Hebei region,China     

Zizhan Hu  Xuguang Tang  Chen Zheng  Menglin Guan  Jingwei Shen 《Environmental Earth Sciences》2018,77(14):540

Due to its negative impact on the living environment of human beings, ambient air pollution has become a global challenge to human health. In this study, surface observations of six criteria air pollutants, including PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃, were collected to investigate the spatial and temporal variation in the Beijing–Tianjin–Hebei (BTH) region during 2013–2016 and to explore the relationships between atmospheric pollutants and meteorological variables using quantile regression model (QRM) and multiple linear regression model (MLRM). The results show that BTH region has experienced significant air pollution, and the southern part generally has more severe conditions. The annual average indicates clear decreasing trends of the particulate matters, SO₂ and CO concentrations over the last 4 years and slight increasing trends of NO₂ and O₃ in several cities. The seasonal and monthly characteristics indicate that the concentrations of five species reach their maxima in the winter and their minima in the summer, whereas O₃ has the opposite behaviour. Finally, the pseudo R² values show that the QRMs have the best performance in the winter, followed by spring, fall, and summer. Specifically, all the meteorological factors have significant impacts on air pollution but change with pollutants and seasons. The MLRM results are generally consistent with the QRM results in all seasons, and the inconsistencies are more common in the fall and winter. The results of this research provide foundational knowledge for predicting the response of air quality to climate change in the BTH region.  相似文献   

Assessment of dynamic impact force of debris flow in mountain torrent based on characteristics of debris flow     

Man-Il Kim  Jae-Hwan Kwak  Byung-Sik Kim 《Environmental Earth Sciences》2018,77(14):538

Landslides and debris flows that occur around residential areas are considered, globally, as significant disasters that cause damage to human life and property. With terrain slope defining the flow characteristics of debris flows, flow depth, flow velocity, and impact force vary by time and distance. In particular, when a structure is located in the flow path of debris flows, the flow characteristics of debris flows vary by terrain slope and direction angle. To simulate the flow characteristics of these debris flows, the simulation results obtained by FLO-2D were analyzed with six-stage conditions for the research area. In the analysis, the flow depth, flow velocity, and impact force were estimated on the basis of the outlet of the research area in the presence and absence of structure(s) at certain distances. With this, the variation of the impact force in accordance with the variation of the flow depth of the debris flows was highly similar to the simulation results obtained by FLO-2D, when the correction index (α) of the suggested dynamic impact force equation was 0.3–0.4. There were sections where the estimated value of the impact force was overestimated near the outlet, and it was judged that the fixed values of the terrain factors (width, roughness coefficient, slope, etc.) caused the impact force to be overestimated. However, the correlation analysis showed that the correlation index was above the normal ranges in the suggested dynamic impact force equation for debris flows with the application of the terrain factors.  相似文献   

Dependence of radon exhalation on grain size of sedimentary waste     

Eman M. Ibrahim  Ibrahim E. El Aassy  Hayam Ahmed Abdel Ghany  S. H. Gamil 《Environmental Earth Sciences》2018,77(14):534

Tailings resulted from sulphuric acid leaching process of uranium from sedimentary rocks contain high concentrations of ²²⁶Ra and its daughters, the most important of which is ²²²Rn. Movement of radon gas out of the tailings is strongly influenced by the physicochemical characteristics of these tailings especially their radium content and the grain size. So, the tailing samples were size fractionated into four sizes (>?250, 250–125, 125–74 and <?74 µm). The natural radioactivity was investigated using hyper-pure germanium detector and solid-state nuclear track detectors (CR-39) for bulk size and after size fractionation. The activity concentrations of different radionuclides in size-fractionated tailing samples have been shown to be strongly dependent on the size of the particles. In the range of >?250 and <?74 µm, the activity concentrations of ²³⁰Th, ²²⁶Ra, ²¹⁴Pb, ²¹⁴Bi, ²¹⁰Pb, ²³²Th and ⁴⁰K increased throughout with decreasing particle size, while that of ²³⁸U, ²³⁴U and ²³⁵U have an opposite effect. The results revealed an inverse relationship between the radon exhalation rate and size fractionation. Also, the results showed a good correlation between radium activity concentration and radon mass exhalation rate.  相似文献   

Soil column infiltration tests on biomediated capillary barrier systems for mitigating rainfall-induced landslides     

Sheng Hua Tan  Shi Wei Wong  Du Jia Chin  Min Lee Lee  Ying Hui Ong  Siaw Yah Chong  Azman Kassim 《Environmental Earth Sciences》2018,77(16):589

Rainfall-induced landslide is a common geohazard in tropical and humid regions. Capillary barrier system (CBS) is a popular and widely studied mitigating measure for rainfall-induced landslides. However, several previous studies have shown that the performance of the conventional CBS under intense rainfalls has not been particularly convincing. This paper aims to explore the feasibility and effectiveness of a newly proposed system, known as “biomediated capillary barrier system” (B-CBS) in minimizing water infiltration into soil. A one-dimensional soil column was used to investigate the infiltration characteristics of the proposed system. The results showed that the B-CBS of biomediated residual soil overlying original residual soil (Test IV) could effectively control the infiltration into soil by taking advantage of the less-permeable biomediated soil cover. The B-CBS of biomediated residual soil overlying gravelly sand (Test V) and the three-layered B-CBS of fine sand overlying gravelly sand and biomediated residual soil (Test VI) showed the best performance in terms of minimizing the water infiltration. A suction of about 5 kPa still remained in the soil column after 60 min of infiltration from the ponded water on the soil surface.  相似文献   

Numerical simulation of lifetime and time-dependent damage for granite by continuous and discontinuous approaches     

Wei Chen  Xiang Li  Heinz Konietzky 《Environmental Earth Sciences》2018,77(16):594

In this study, the time-dependent damage process of granite is investigated utilizing two numerical simulation schemes based on continuous method and discontinuous method. Numerical creep tests are carried out with both simulation schemes and mechanical responses and fracture patterns of rock specimens are analyzed. The calibrated numerical models can successfully reflect the typical creep stages observed in the laboratory. The predicted lifetime is in accordance with the laboratory test data. Comparisons are made between the two simulation schemes. It is found that both schemes have unique features that can promote a genuine reflection of the time-dependent damage process of the brittle rocks.  相似文献   

Evidence for the occurrence of hydrogeochemical processes in the groundwater of Khoy plain,northwestern Iran,using ionic ratios and geochemical modeling     

Rahim Barzegar  Asghar Asghari Moghaddam  Amir Hossein Nazemi  Jan Adamowski 《Environmental Earth Sciences》2018,77(16):597

Rapid population growth, industrialization, and agricultural expansion in the Khoy area (northwestern Iran) have led to its dependence on groundwater and degradation of groundwater quality. This study attempts to decipher the major processes and factors that degrade the groundwater quality of the Khoy plain. For this purpose, 54 groundwater samples from unconfined and confined aquifers of the plain were collected in July 2017 and analyzed for major cations and anions (Na, K, Ca, Mg, HCO₃, SO_4, and Cl), minor ions (NO₃ and F), and Al. Magnesium and bicarbonate were identified as the dominant cation and anion, respectively. Several ionic ratios and geochemical modeling using PHREEQC indicated that the most important hydrogeochemical processes to affect groundwater quality in the plain were weathering and dissolution of evaporitic and silicate minerals, mixing, and ion exchange. There were smaller effects from evaporation and anthropogenic factors (e.g., industries). Results showed that the high salinity of the groundwater in the northeast area of the plain was due to the high solubility of the evaporitic minerals, e.g., halite and gypsum. Reverse ion exchange and the contribution of mineral dissolution were more significant than ion exchange in the northeastern part of the plain. Elevated salinity of the groundwater in the southeast was attributed mostly to reverse ion exchange and somewhat to evaporation.  相似文献   

Groundwater characteristics within loessic deposits: the coastal springs of Los Acantilados,Mar del Plata,Argentina     

Federico Ignacio Isla  Orlando Mauricio Quiroz Londoño  Luis Camilo Cortizo 《Environmental Earth Sciences》2018,77(17):610

The urban growth of the southern neighborhoods of Mar del Plata City provoked significant changes in the groundwater balance of the loessic sequences. These regional loessic levels with a significant portion of volcanic ash layers were reported subject to fluoride and nitrate concentrations. Residential houses pump from sands located 70 m depth and withdraw the sewages to depths less than 5 m. These effects cause significant local and seasonal (summer) increments of the water table outcropping via springs at certain unconformities of the coastal cliffs. A mathematical model was applied to analyze the water level lowering at the productive levels, while there is a decrease in the quality of the upper levels subject to waste discharges. Much of this groundwater flow is concentrated in unconformities between different types of sediments. Human activities have affected the aquifer dynamics increasing the groundwater pumping rates and the return velocity of the sewages. This should be considered in the management strategies of coastal hydric resources.  相似文献   

Up-to-date urban rainstorm intensity formulas considering spatial diversity in China     

Danna Shao  Guang-sheng Liu 《Environmental Earth Sciences》2018,77(14):541

With accelerating urbanization in China, urban waterlogging has had a serious impact on urban sustainable development and citizen welfare. Simple urban rainstorm intensity formulas with a monotonous frequency distribution type cannot meet the practical needs of urban drainage planning and design. This study focuses on the development of urban rainstorm intensity formulas based on spatial diversity in China. Using the annual maximum sampling method, rainstorm data of 607 cities throughout China were collected into a database, with a total of 24,933 rainfall samples (annual observations) under various specified precipitation durations. The database was used to verify that integrating the Pearson III and Gumbel distributions would constitute an optimal theoretical distribution type, owing to its small error and increased fitting precision. Modification and coordination of four important parameters in the rainstorm intensity formula were done using a digital elevation model, which improved the accuracy of the formula. In addition, precipitation distributions in China were treated from the perspective of topographic features to validate the calculations from up-to-date formulas. Accuracy assessment was accomplished using a national code (GB-50014-2006), GIS-based isograms, and authoritative results from the Hydrological Bureau of the Ministry of Water Resources. This work provides a comprehensive foundation for the establishment of an up-to-date rainstorm intensity formula for China, which can be used widely in different cities.  相似文献