Study on polycyclic aromatic hydrocarbons（PAHs） contents and sources in the surface so~l or l-lmznou City, South China, based on multivariate statistics analysis

Studies of polycyclic aromatic hydrocarbons (PAHs) in the surface soil were conducted in Huizhou City, which is located in the Pearl River Delta, South China. Sixteen PAHs in 42 soil samples were detected. The results showed that 4 components of PAHs were detectable in all soil samples, and other 12 components were also detectable to some extent. The total PAHs contents range from 35.40 to 534.5 μg/kg with the mean value of 123.09 μg/kg. Soil in Huizhou was slightly polluted by PAHs according to Maliszewska-Kordybach’s study. It can be confirmed that the increase of PAHs contents in the surface soil of Huizhou City is closely connected to human activities. Multivariate analysis was also made in this study. Principal component analysis was used to constrain their origins, and 3 principal components (PCs) were extracted. The results showed that coal combustion and oil spilling made the major contributions to PAHs. Cluster analysis was made and 16 priority PAHs were classified as 4 sorts, and the result revealed the differences in environmental behavior, chemical properties and sources of PAHs.     

Pan-African high-grade metamorphism of southern Sinai,Egypt, fluid inclusion evidence

Fluid inclusions in the leucosomes of Wadi Feiran migmatites showed that CO ₂ , H₂O and (H₂O-CO₂) fluids were likely to have been present when partial melting began in these rocks. Low salinity, aqueous fluid, to a lesser extent, CO₂-rich fluids are the most abundant fluids. The present study suggests that high-density CO₂ inclusions were formed at the earliest stage, while H₂O inclusions were formed at the late stage. In an intermediate stage, low-density CO₂ and H₂O, CO₂ inclusions were formed. At the early stage of uplift and during melt crystallization, the CO₂-bearing vapour was trapped at grain boundaries. At the late stage of uplift, H₂O released at the time of crystallization of the melt was trapped as inclusions.     

Modelling soil erosion from a watershed using cubic splines

Erosion in a watershed exhibits spatial and temporal variability, and its determination is fundamental to determining sediment yield which is a key to proper watershed management. In this study, we propose a relationship between the curve number (SCS 1956) and Sediment Yield Index (SYI) using cubic splines. The method is illustrated with a case study of one watershed of Narmada Basin located in Mandla district of Madhya Pradesh, India. Cubic splines are found to perform satisfactorily with Nash efficiency of 63.64%, absolute prediction error of 2.64%, integral square error of 1.22%, coefficient of correlation of 93.78% and degree of agreement of 0.99%. The relation between observed and computed SYI values is correlated with a coefficient of determination (R ²) of 0.87. Such a relationship can be used to determine SYI from the available CN value, which may be quite useful in field applications.     

Earthquake hazard assessment through geospatial model and development of EaHaAsTo tool for visualization: an integrated geological and geoinformatics approach

An earthquake is a natural phenomenon which is very frequent in Himalayan region in India. In southern peninsula India, the spatial occurrence of earthquake is irregular, whereas the northeastern, the north and the northwestern Himalayan parts of India are subjected to regular occurrences of earthquakes as they mark the boundary of the Eurasian and the Indian Plate. Hence, it is important to study and develop spatial model and information tool to understand the seismic phenomenon. The geoinformatic technique plays a significant role in the analysis of geodatabase to study the natural disaster and hazard assessment. The main aim of the present study is to develop geospatial model based on earthquake hazard assessment tool (EaHaAsTo) through integrated geological and geoinformatic techniques to better understand the earthquake occurrences zones. The spatial and non-spatial data were collected and integrated in a GIS to prepare geospatial databases. The thematic and quantitative databases were generated, and analysis was carried out to understand the seismic characteristics of the study area. The geospatial model was developed by integrating thematic databases and geospatial analyzed using weighted linear combination method. Finally, the GIS based on customized EaHaAsTo was developed to visualize the output of the model in qualitative and quantitative forms.     

Numerical investigation of slippage characteristics of normal and reverse faults under fluid injection and production

Nowadays, a great deal of petroleum geology and engineering projects associated with underground fluid injection and production (FIP) are widely conducted around the world. The FIP engineering may cause complex stress perturbation and trigger seismicity, which have been extensively reported and studied. In this paper, we investigated the fault slippage characteristics influenced by FIP. It reveals that for a fault (normal or reverse) that penetrating through the reservoir into the caprock and underburden, the footwall reservoir is the relatively stable one for fluid injection in a fluid FIP engineering. No matter it is a normal or a reverse fault, injecting fluid into footwall reservoir and producing fluid from the hanging wall reservoir can induce smaller fault slippage. After having determined the better fluid injection–production pattern, we studied the influence of three key factors of fault, i.e., dip, offset and depth, on fault stability. We found that, in our range of study, the influence of single action of fault dip, offset or depth on fault slippage in a FIP engineering was small. However, the influence of the combined effects of the factors may be large. Finally, we studied the effect of different pressure management scenarios on fault responses based on the specific fluid injection–production pattern. The results revealed that appropriate pressure management could effectively reduce fault slippage in a FIP engineering. However, inappropriate pressure management may cause much larger fault slippage. Given these concerns, it is therefore vital that the effect of pressure management scenario to be modeled prior to FIP.     

A novel geographical information system-based Ant Miner algorithm model for delineating groundwater flowing artesian well boundary: a case study from Iraqi southern and western deserts

The Ant Miner algorithm was compared with the bivariate frequency ratio (FR) and boosted regression trees (BRT) algorithms in terms of its capacity to assess groundwater potential. A geospatial dataset was prepared that contains two components: a flowing well inventory map and eleven factors relevant to groundwater conditions. Average nearest neighbor technique was used to investigate the spatial pattern of flowing wells and to find the appropriate distance between flowing and nonflowing points in the study area. A wrapper approach known as random forest classifier and a filtering approach known as information gain ratio were used to identify the most relevant groundwater factors. The developed models were validated via the area under the operating characteristic curve. Results revealed that the Ant Miner model performed better in terms of both success (0.944) and prediction (0.92) rates compared to FR and BRT. Furthermore, the Ant Miner algorithm derived five simple, easily interpreted rules for predicting groundwater potential that can be used by hydrogeologists for identifying potential groundwater well locations with minimal effort and cost.     

Aliphatic hydrocarbons in coastal sediments of the Northern Cyprus (Eastern Mediterranean)

The sources and spatial distributions of aliphatic hydrocarbon concentrations were investigated in surficial sediments of the Northern Cyprus (Gemi Konagi, Girne and Gazi Magusa Areas). Aliphatic hydrocarbon levels were determined with a gas chromatography–mass spectrometer. Total aliphatic hydrocarbon (n-alkanes, Σ25; isoprenoids, Σ2) concentrations in the sediments were found in the range of 1107–6360 ng/g. Results indicated that the sediments were mainly dominated by odd numbered n-alkanes (n-C10–n-C34), maximizing at n-C17, n-C29 and n-C31. Statistical analyses and diagnostic ratios have been used to determine the possible sources and origins of aliphatic hydrocarbons. Aliphatic hydrocarbons were showed biogenic character at all sampling areas and were found mainly originated from terrestrial, marine and both terrestrial-marine plants at Gemi Konagi, Gazi Magusa and Girne, respectively.     

Between-Population Differences in Multi-stressor Tolerance During Embryo Development in the American Horseshoe Crab, <Emphasis Type="Italic">Limulus polyphemus</Emphasis>

The American horseshoe crab, Limulus polyphemus, is found along the Atlantic and Gulf of Mexico coasts in genetically isolated populations. Eggs are laid in shoreline beaches that expose developing embryos to combinations of environmental stressors. Whether populations of L. polyphemus differ in multi-stressor tolerance had never been tested. We assessed the multi-stressor tolerance of L. polyphemus embryos from a population in Delaware Bay (DE) and determined whether these differed from the multi-stressor tolerance of embryos from a more southerly Florida Gulf Coast (FGC) population. We monitored the field sediment temperatures and determined multi-stressor tolerance of DE embryos, then compared these to published data for FGC embryos. For multi-stressor tolerance, we assessed development success of embryos in 2-week exposures to 36 full-factorial combinations of temperature (20, 25, 30, 35 °C), salinity (5, 15, and 34 ppt), and ambient O₂ (5, 13, and 21% O₂), followed by 2 weeks in recovery conditions. Sediment temperatures in the DE site ranged from 9.5 to 46 °C, with extended periods exceeding 35 °C. Development success was similar between the DE and FGC populations in 14 of 26 multi-stressor combinations. The DE embryos were generally more successful in conditions that included high temperature or moderate hyposalinity, whereas the FGC embryos were generally more successful in conditions that included extreme hyposalinity. This suggests that although multi-stressor tolerances are generally similar between the two populations, specific differences exist that correlate more with differences in nest microenvironment than latitude.     

Hydrogeochemical assessment of surface and groundwater resources of Korba coalfield,Central India: environmental implications

The present study assesses the impact of coal mining on surface and groundwater resources of Korba Coalfield, Central India. Accordingly, water samples collected from various sources are analyzed for major ions, trace elements, and other mine effluent parameters. Results show that the groundwater samples are slightly acidic, whereas river water and mine water samples are mildly alkaline. Elevated concentrations of Ca²⁺, Na⁺, HCO₃ ^?, and SO₄ ^2? alongside the molar ratios (Ca²⁺+Mg²⁺)/(SO₄ ^2?+HCO₃ ^?) <1 and Na⁺/Cl^? >1 suggest that silicate weathering (water-rock interaction) coupled with ion exchange are dominant solute acquisition processes controlling the chemistry of groundwater in the study area. The overall hydrogeochemistry of the area is dominated by two major hydrogeochemical facies (i.e., Ca–Cl–SO₄ and Ca–HCO₃). Analysis of groundwater and river water quality index (GRWQI) elucidates that majority (82%) of samples are of “excellent” to “good” category, and the remaining 12% are of “poor” quality. Similarly, the effluent water quality index (EWQI) indicates that 6 out of 8 samples belong to excellent quality. Concentration of trace element constituents such as As, Zn, Cu, Cr, and Cd is found to be well within the stipulated limits for potable use, except for Fe, Mn, and Pb. Suitability of water samples for irrigation purpose, established using standard tools like Wilcox and USSL diagrams, reveal “excellent to permissible” category for majority of the samples. The present study also substantiates the effectiveness of the measures implemented for the treatment of mine effluent water.     

Mapping thermal comfort in Iran based on geostatistical methods and bioclimatic indices

The cognition of thermal comfort plays a pivotal role in human life and activities. Recognizing thermal comfort based on climatic parameters is substantially significant. The main objective of the present study is to map thermal comfort using statistics from 43 meteorological stations, from 1970 to 2013. Initially, according to temperature and relative humidity, annual and seasonal thermal comfort conditions were mapped, and later bioclimatic human thermal comfort conditions in line with spatial factors were zoned based on bioclimatic indexes of Temperature Humidity Index (THI), effective temperature (ET) and Relative Strain Index (RSI). Among geostatistical methods, empirical Bayesian kriging (EBK) method with less RSME is more efficient. The annual distribution of temperature changes according to spatial factors of rugged topography and elevation, and latitude affects relative humidity. Thermal comfort in the northern and western half of Iran is higher than the southern and eastern areas of the country. Spatial factors of latitude and altitude reduce bioclimatic uniformity and create small areas with or without thermal comfort conditions. Bioclimatic indicators based on air temperature and relative humidity range of bioclimatic zones show. The results of ET and THI divide the whole country into six zones, from lack of thermal comfort to having thermal comfort conditions. Areas of southern strip as well as central and southeastern parts of the country do not have any human thermal comfort conditions in most of the year.