Probabilistic Nucleation and Crystal Growth in Porous Medium: New Insights from Calcium Carbonate Precipitation on Primary and Secondary Substrates.

Knowledge of crystal nucleation and growth is paramount in understanding the geometry evolution of porous medium during reactive transport processes in geo-environmental studies. To predict transport properties precisely, it is necessary to delineate both the amount and location of nucleation and precipitation events in the spatiotemporal domain. This study investigates the precipitation of calcium carbonate crystals on a heterogeneous sandstone substrate as a function of chemical supersaturation, temperature, and time.

In situ remediation of Cr(VI) contaminated groundwater by ZVI-PRB and the corresponding indigenous microbial community responses: a field-scale study.

The performance of a permeable reactive barrier (PRB) for the in situ remediation of hexavalent chromium [Cr(VI)] contaminated groundwater, and the resulted responses in the indigenous microbial community, were investigated in a field-scale study. The PRB consisted of a mixture of zero-valent iron (ZVI), gravel and sand. The results showed that the PRB segment with 20% active reaction medium (ZVI) was able to successfully reduce Cr(VI) via chemical reduction from 27.

Twenty-first century hydrologic and climatic changes over the scarcely gauged Jhelum river basin of Himalayan region using SDSM and RCPs.

Climatic and hydrological changes of the scarcely gauged mountainous basins remain a challenge to study due to unavailability of observed data. The recent study aims to assess these changes using spatial decision tool statistical downscaling method (SDSM) and snowmelt runoff model (SRM) for the twenty-first century under representative concentration pathways (RCPs). SDSM considered absolute partial correlation coefficient (abs.

Overview of terrestrial water storage changes over the Indus River Basin based on GRACE/GRACE-FO solutions.

Water resources are under severe stress in the highly populated Indus River Basin due to the increased consumption of water across different sectors and climate change. Coping with these challenges, requires a clear understanding on hydrological processes and anthropogenic activities, and how these are influencing recharging and spatiotemporal availability of groundwater in the basin. The present study aims to investigate the natural and anthropogenic impact on Terrestrial Water Storage (TWS) over the Indus River Basin by using a series of statistical methods and the observation data from the Gravity Recovery and Climate Experiment (GRACE) and Follow-On (GRACE-FO).

Polycyclic Aromatic Hydrocarbon Levels in Wistar Rats Exposed to Ambient Air of Port Harcourt, Nigeria: An Indicator for Tissue Toxicity.

This study investigated the PAH levels in Wistar rats exposed to ambient air of the Port Harcourt metropolis. Twenty Wistar rats imported from a nonpolluted city (Enugu) were exposed to both indoor and outdoor air. Following the IACUC regulation, baseline data were obtained from 4 randomly selected rats, while the remaining 16 rats (8 each for indoor and outdoor) were left till day 90.

Insights into the kinetic processes of solute migration by unidirectional freezing in porous media with micromodel visualization at the pore-scale.

Field investigations have proved that frozen soil does not act as a completely impermeable barrier for contaminants in cold regions. However, the subsurface behaviors of solutes in freezing and frozen porous media are still unclear. To unveil their nature, the pore-scale behavior of potassium permanganate in saturated porous media subjected to the unidirectional freezing was investigated using micromodel visualizations.

Grassland ecological restoration based on the relationship between vegetation and its below-ground habitat analysis in steppe coal mine area.

Coal mining activities have caused severe disturbances to the regional ecosystem and soil properties. Studying the relationship of vegetation and its below-ground habitat (RVBGH) is of great significance to the coal mine land ecological restoration. To identify the optimal thickness of the soil layer for mine land ecosystem recovery and characterize the changes of the reclaimed soil-vegetation ecosystem, we studied natural and reclaimed grassland at the coal mine of Baorixile, located in Hulunbuir Steppe, Northeastern China.

Characterization of dissolved organic matter derived from coal gangue packed in underground reservoirs of coal mines using fluorescence and absorbance spectroscopy.

Organic and nitrogen pollutants in mine water could be removed effectively during the storage and transport of water in a coal mine underground reservoir packed with coal gangue through various water-rock interactions. However, little is known about the effect of the released dissolved organic matter (DOM) derived from the packed matrix on their removal. Column experiments were performed at a Darcy flux of 1.

Predicting long-term dynamics of soil salinity and sodicity on a global scale.

Knowledge of spatiotemporal distribution and likelihood of (re)occurrence of salt-affected soils is crucial to our understanding of land degradation and for planning effective remediation strategies in face of future climatic uncertainties. However, conventional methods used for tracking the variability of soil salinity/sodicity are extensively localized, making predictions on a global scale difficult. Here, we employ machine-learning techniques and a comprehensive set of climatic, topographic, soil, and remote sensing data to develop models capable of making predictions of soil salinity (expressed as electrical conductivity of saturated soil extract) and sodicity (measured as soil exchangeable sodium percentage) at different longitudes, latitudes, soil depths, and time periods.

[Source of Groundwater Nitrate in Luanping Basin Based on Multi-environment Media Nitrogen Cycle and Isotopes].

The multi-environment media of water, surface soil and vadose zone soil samples were collected in the upstream of Miyun Reservoir, in the Luanping Basin of Chengde City, Hebei Province. The aim was to identify the pollution source, ratio, spatial distribution, migration, and transformation characteristics of nitrogen in groundwater. Hydrogeochemistry, soil total nitrogen, and dissolved nitrate nitrogen of vadose zone soil analysis and a multi isotope tracer technique of N-NO and O-NO, S-SO and O-SO, C, combined with land-use type analysis and geostatistics, were used in the study.

Source Tracking and Risk Assessment of Pharmaceutical and Personal Care Products in Surface Waters of Qingdao, China, with Emphasis on Influence of Animal Farming in Rural Areas.

The occurrence and potential sources of pharmaceuticals and personal care products (PPCPs) in surface waters from a large coastal city Qingdao, North China, were investigated. Forty-five compounds were analyzed by high-performance liquid chromatography-tandem mass spectrometry. The results showed that 28 compounds of PPCPs were detected.

Quantifying nanoparticles in clays and soils with a small-angle X-ray scattering method.

Clays and soils produce strong small-angle X-ray scattering (SAXS) because they contain large numbers of nanoparticles, namely allophane and ferrihydrite. These nanoparticles are amorphous and have approximately spherical shape with a size of around 3-10 nm. The weight ratios of these nanoparticles will affect the properties of the clays and soils.

Assessment of forest cover and carbon stock changes in sub-tropical pine forest of Azad Jammu & Kashmir (AJK), Pakistan using multi-temporal Landsat satellite data and field inventory.

This study aimed at estimating temporal (1989-2018) change in forest cover, carbon stock and trend in corresponding CO2 emissions/sequestration of a sub-tropical pine forest (STPF) in AJK, Pakistan. Our field inventory estimation shows an average above ground biomass (AAGB) accumulation of 0.145 Kt/ha with average carbon stock (ACS) value of 0.

Topographic variables to determine the diversity of woody species in the exclosure of Northern Ethiopia.

Exclosures are established with the objective of rehabilitating degraded lands and restoring of woody vegetation. Various studies have been conducted to evaluate the success of exclosure on restoring woody species diversity. However, works focusing on the effect of topographic factors on woody species diversity are scarce.

[Temporal Response of Subterranean Karst Stream Hydrochemistry to Urbanization].

The hydrochemical responses of underground rivers to urbanization were studied using a 25-year groundwater observation dataset and remote sensing. We found that as urbanization progresses, the mineralization degree of underground rivers gradually increases; time-series data for dominant hydrochemical indicators changed from HCO·SO-Ca·Mg during the dry season and HCO-Ca·Mg during flood season to HCO·Cl-Ca, HCO·SO-Ca, HCO-Ca, and HCO·SO-Ca·Mg. Influenced by surface precipitation input, the groundwater chemistry of underground rivers varies greatly during the dry season and the flood season.

[Distribution of 16 Polycyclic Aromatic Hydrocarbons in Dianchi Lake Surface Sediments After the Integrated Water Environment Control Project].

The external pollution of Dianchi Lake has been effectively controlled with the implementation of the integrated water environment control project. However, further attention should be paid to endogenous pollutants, such as surface sediments. To investigate the distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Dianchi Lake, PAH concentrations in 19 surface sediment samples (collected in December 2016) were quantitatively measured by gas chromatography-mass spectrometry (GC-MS).

Coupling logistic model tree and random subspace to predict the landslide susceptibility areas with considering the uncertainty of environmental features.

Landslide disasters cause huge casualties and economic losses every year, how to accurately forecast the landslides has always been an important issue in geo-environment research. In this paper, a hybrid machine learning approach RSLMT is firstly proposed by coupling Random Subspace (RS) and Logistic Model Tree (LMT) for producing a landslide susceptibility map (LSM). With this method, the uncertainty introduced by input features is considered, the problem of overfitting is solved by reducing dimensions to increase the prediction rate of landslide occurrence.

Spatial distribution and accessibility to public sector tertiary care teaching hospitals: case study from Pakistan.

Background: Public sector provision of health care services is important for addressing health morbidity and mortality burden for population health in developing countries like Pakistan. Physical accessibility and spatial distribution of healthcare facilities affect their utilization for improving population health.

Aims: This study aimed to analyze the spatial distribution of five public sector, tertiary care, teaching, general hospitals in the city of Lahore, Pakistan.

Changing climate both increases and decreases European river floods.

Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe. Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning.

Combining hydrological investigations and radium isotopes to understand the environmental effect of groundwater discharge to a typical urbanized estuary in China.

Pollution of urbanized rivers with excess nutrients due to groundwater discharge is an increasing environmental concern worldwide. Dan'ao river, a typical urbanized river in the Guangdong-Hong Kong-Macao Greater Bay Area, is experiencing heavy water pollution. However, the groundwater-derived nutrient loads had not yet been thoroughly quantified.

Deformation Activity Analysis of a Ground Fissure Based on Instantaneous Total Energy.

This study proposes a novel instantaneous total energy method to perform an activity analysis of ground fissures deformation, which is calculated by integrating the extreme-point symmetric mode decomposition (ESMD) method and kinetic energy based on the time-series displacement acquired by shape acceleration array (SAA) sensors. The proposed method is tested on the Xiwang Road fissure in Beijing, China. First, to fully monitor the hanging wall and footwall of the monitored ground fissure, a 4 m-long SAA in the vertical direction and an 8 m-long SAA in the horizontal direction were embedded in a ground fissure to obtain an accurate time-series displacement with an accuracy of ±1.

Spatial Cluster Analysis Of New And Relapsed Cases Of Pulmonary Tuberculosis By District: Pakistan 2015.

Tuberculosis (TB) is a major public health problem in Pakistan. There are no studies in Pakistan on TB disease mapping and spatial analysis at the country level. This study was conducted to map and identify clusters of TB incidence rates at the district level for all provinces of Pakistan, including Islamabad for all new and relapsed cases of pulmonary TB, for the year 2015.

Hydrothermal ore deposits in collisional orogens.

Hydrothermal ore deposits at convergent plate boundaries represent extraordinary metal enrichment in the continental crust. They are generally associated with felsic magmatism in extensional settings at high thermal gradients. Although their formation is common during accretionary orogeny, more and more ore deposits have been discovered recently in the collisional orogens of China.

Spatial Distribution and Accessibility to Public Sector Tertiary Care Teaching General Hospitals: Tale of Two Khyber Pakhtunkhwa Districts - Peshawar and Abbottabad.

Effective utilisation of healthcare facilities is determined by spatial and non-spatial factors, including their spatial distribution and physical accessibility. Public sector plays an important role in the provision of healthcare services for improving health in developing countries like Pakistan. We analysed the spatial distribution and accessibility to public sector tertiary care teaching and general hospitals in the Khyber Pakhtunkhwa (KPK) districts of Abbottabad and Peshawar.

Post-failure behavior analysis of the Shenzhen "12.20" CDW landfill landslide.

Since the 1990s, with rapid economic development and urbanization occurring in many countries, the amount of construction and demolition waste (CDW) has also increased. Landfills have become the most commonly used method of disposing of CDW. The safety of landfill slopes is very important.