パキスタン・東部パンジャブ地方におけるヒ素とフッ素による地下水・土壌汚染の性質とその拡大 : 天然の水循環系におけるこれらの汚染物質の移動を規制する地球化学的要因と推定される汚染源について

博士(理学)大阪市立大

Metabolomics profiling reveals the detoxification and tolerance behavior of two bread wheat (Triticum aestivum L.) varieties under arsenate stress

Acknowledgment Swedish Metabolomics Centre, Umeå, Sweden (www.swedishmetabolomicscentre.se) is acknowledged for metabolic profiling by LC-TOF-MS and amino acid quantification by LC-QqQ-MSMS. We acknowledge Muhammad Anas (Quaid-i-Azam University, Islamabad) for his valuable contribution for data analysis in this study.Peer reviewe

Geochemical control on spatial variability of fluoride concentrations in groundwater from rural areas of Gujrat in Punjab, Pakistan

Spatial variability and geochemical factors controlling fluoride (F−) concentrations were evaluated in five villages of subdistrict Gujrat in Pakistan. Groundwater samples (n = 70) were collected along the River Chenab and examined for F− concentrations. The average F−concentrations in groundwater of village Chhani Nikoani (1.8 mg/L) and Dhool Khurd (2.2 mg/L) were crossing the World Health Organization (WHO) permissible limit of 1.5 mg/L, while village Kalra Khasa, Ghazi Chak and Kula Chor were below the WHO guidelines. About 64 % of the samples contain fluoride concentrations that exceed the 1.5 mg/L drinking water standard set by WHO. Spatially F− concentrations in groundwater increased as moving away from the River Chenab because more residence time for water–rock interaction was available. High F− concentrations were associated with high electric conductivity (EC), total dissolved solids (TDS), pH and Na+ values. The overall groundwater quality is controlled by silicate mineral weathering and less by evaporation. Fluoride originates from anion exchange (OH− for F−) on clays and weathered micas under high pH conditions. High fluoride levels are associated with NaCl- and NaHCO3-type water produced by calcite precipitation and/or base ion exchange. The groundwater with higher fluoride concentrations is accompanied by lower Ca+2levels. This study enhances our understanding on geochemical behavior of F and highlights the importance of spatial variability on F release in aquifers of Punjab in Pakistan, as well as in other countries of Asia region

Machine learning-based assessment and simulation of land use modification effects on seasonal and annual land surface temperature variations

Rapid urban sprawl adversely impacts the local climate and the ecosystem components. Islamabad, one of South Asia's green and environment-friendly capitals, has experienced major Land Use Land Cover (LULC) changes over the past three decades consequently, elevating the seasonal and annual Land Surface Temperature (LST) in planned and unplanned urban areas. The focus of this study was to quantify the fluctuations in LULC and LST in planned and unplanned urban areas using Landsat data and Machine Learning algorithms involving the Support Vector Machine (SVM) over the 1990–2020 data period. Moreover, hybrid Cellular Automata-Markov (CA-Markov) and Artificial Neural Network (ANN) models were employed to project the future changes in LULC and annual LST, respectively, for the years 2035 and 2050. The findings of the study reveal a distinct difference in seasonal and annual LST in planned and unplanned areas. Results showed an increase of ∼22 % in the built-up area but vegetation and bare soil decreased by ∼10 % and ∼12 %, respectively. Built-up land showed a maximum annual mean LST followed by bare-soil and vegetative surfaces. Seasonal analysis showed that summer months experience the highest LST, followed by spring, autumn and winter. Future projections revealed that the built-up areas (∼27 % in 2020) are likely to increase to ∼37 % and ∼50 %, and the areas under the highest annual mean LST class i.e., ≥28 °C are likely to increase to ∼19 % and ∼21 % in planned, and ∼38 % and ∼42 % in unplanned urban areas for the years 2035 and 2050, respectively. Planned areas have better temperature control with urban green spaces, and controlled infrastructure. The Capital Development Authority of Islamabad may be advised to control the expansion of built-up areas, grow urban forests, and thus mitigate the possible Urban Heat Island (UHI) effect

Comparison of two alluvial aquifers shows the probable role of river sediments on the release of arsenic in the groundwater of district Vehari, Punjab, Pakistan

The study was done to assess the effect of the river Sutlej on arsenic (As) contamination. Sampling was done from the alluvial plain with increasing distance from the river Sutlej in district Vehari and compared with the study done in the proximity of River Sutlej. Sixty (60) groundwater samples mostly from shallow depths were collected and analyzed for As concentrations. Multivariate statistical tools (PCA and CA), saturation index, piper plots and Gibbs diagrams were used to detect evidence about the interrelationship and sources of As and other water quality variables responsible for groundwater contamination. Results revealed that As concentration ranged from below detection limit to 156 A mu g/L indicating that 50% samples exceeding the WHO guidelines (10 A mu g/L) and 17% exceeding the Pakistan National Environmental Quality Standards (NEQS) limits (50 A mu g/L) Sutlej. The piper plot revealed that water chemistry of the study area was Ca-HCO3 (-), Ca-Mg-Cl, type. Correlations between As and HCO3 (-) (r (2) = 0.433) was positive, while negative correlations were observed between As-Mn2+ and As-Fe2+ (r (2) = - 0.102), (r (2) = 0.107) respectively. Geochemical signatures of the groundwater in the study area showed that the As could be released by oxidative dissolution to some extent and elevated evaporation in the arid environment of the study area under the stimulus of alkaline water and high pH (range 7.1-8.4). Although the concentrations are exceeding the WHO limit in 50% of the water samples but, are less than the previous study done in Mailsi near River Sutlej. Further, the concentrations decreased as the distance from the River increased which shows the probable role of sediments deposited by the River Sutlej

Arsenic and fluoride removal by potato peel and rice husk (PPRH) ash in aqueous environments

Finding appropriate adsorbent may improve the quality of drinking water in those regions where arsenic (As) and fluoride (F(-)) are present in geological formations. In this study, we evaluated the efficiency of potato peel and rice husk ash (PPRH-ash) derived adsorbent for the removal of arsenic and fluoride from contaminated water. Evaluation was done in batch adsorption experiments and the effect of pH, initial adsorbate concentration, contact time and adsorbent dose were studied. The characterization of adsorbents were done using scanning electron micropcope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Both the Langmuir and Freundlich isotherm models fitted well for F(-) and As sorption process. The maximum adsorption capacity of adsorbent for As and F(-) were 2.17 μg g(-1) and 2.91 mg g(-1) respectively. The optimum As and F(-) removal was observed between pH 7 and 9. The sorption process was well explained with pseudo-second order kinetic model. The As adsorption was not decreased in the presence of carbonate and sulfate. Results from this study demonstrated potential utility of this agricultural biowaste which could be developed into a viable filtration technology for As and F(-) removal in As- and F-contaminated water streams

Vertical mixing with return irrigation water the cause of arsenic enrichment in groundwater of district Larkana Sindh, Pakistan

Stable isotopes ratios (parts per thousand) of Hydrogen (delta H-2) and Oxygen (delta O-18) were used to trace the groundwater recharge mechanism and geochemistry of arsenic (As) contamination in groundwater from four selected sites (Larkana, Naudero, Ghari Khuda Buksh and Dokri) of Larkana district. The stable isotope values of delta H-2 and delta O-18 range from 70.78 parts per thousand. to -56.01%parts per thousand and from -10.92 parts per thousand to -7.35 parts per thousand, relative to Vienna Standard for Mean Ocean Water (VSMOW) respectively, in all groundwater samples, thus indicating the recharge source of groundwater from high-salinity older water. The concentrations of As in all groundwater samples were ranged from 2 mu g/L to 318 mu g/L, with 67% of samples exhibited As levels exceeding than that of World Health Organization (WHO) permissible limit 10 mu g/L and 42% of samples expressed the As level exceeding than that of the National Environmental Quality Standard (NEQS) 50 mu g/L. The leaching and vertical mixing with return irrigation water are probably the main processes controlling the enrichment of As in groundwater of Larkana, Naudero, Ghari Khuda Buksh and Dokri. The weathering of minerals mostly controlled the overall groundwater chemistry; rock-water interactions and silicate weathering generated yielded solutions that were saturated in calcite and dolomite in two areas while halite dissolution is prominent with high As area. (C) 2018 Elsevier Ltd. All rights reserved