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11.
Munawar Sultana Taslin Jahan Mou Santonu Kumar Sanyal Farzana Diba Zahid Hayat Mahmud Anowar Khasru Parvez M. Anwar Hossain 《Ground water》2017,55(5):736-746
Arsenotrophic bacteria contribute to the nutrient cycling in arsenic (As) affected groundwater. This study employed a culture‐independent and ‐dependent investigation of arsenotrophic microbiomes in As affected groundwater samples collected from Madhabpur, Sonatengra, and Union Porishod in Singair Upazila, Manikganj, Bangladesh. Total As contents, detected by Atomic Absorption Spectrophotometry (AAS) of the samples, were 47 µg/L (Madhabpur, SNGW‐1), 53 µg/L (Sonatengra, SNGW‐2), and 12 µg/L (Union porishod, SNGW‐3), whereas the control well (SNGW‐4; depths >150 m) showed As content of 6 µg/L. Denaturing Gradient Gel Electrophoresis (DGGE) analysis of the amplified 16S rRNA gene from As‐affected groundwater samples revealed the dominance of aerobic bacteria Pseudomonas within heterogeneous bacterial populations. DGGE of heterotrophic enrichments supplemented with arsenite [As (III)] for 4 weeks showed the dominance of Chryseobacterium, Flavobacterium, and Aquabacterium, whereas the dominant genera in that of autotrophic enrichments were Aeromonas, Acinetobacter, and Pseudomonas. Cultured bacteria retrieved from both autotrophic and heterotrophic enrichments were distinguished into nine genotypes belonging to Chryseobacterium, Acinetobacter, Escherichia, Pseudomonas, Stenotrophomonas, Janibacter, Staphylococcus, and Bacillus. They exhibited varying range of As(III) tolerance from 4 to 27 mM. As(III) transformation potential was confirmed within the isolates with oxidation rate as high as 0.143 mM/h for Pseudomonas sp. Sn 28. The arsenotrophic microbiome specifies their potential role in groundwater As‐cycling and their genetic information provide the scientific basis for As‐bioremediation. 相似文献
12.
Fahad N. Al-Barakah Aly Anwar A. Abaakhel Emad H. S. Al-Rizkid Abdulwahid M. Alghamdi Abdulaziz G. Al-Sewailem Mohammad S. 《Water Resources》2020,47(5):877-891
Water Resources - The objective of this study was to compare and assess the quality and study the hydrochemistry of groundwater in the Al-Baha and Al-Qassim areas, representing the Arabian Shield... 相似文献
13.
为了进一步了解吉尔吉斯斯坦两栖爬行动物物种多样性特征,于2012年9月15日~26日,在对吉尔吉斯斯坦西南部不同生境两栖爬行动物物种多样性进行野外实地调查和已有文献整理的基础上,初步整理出了分布在吉尔吉斯斯坦西南部的两栖爬行动物种类,并其物种多样性进行比较分析。本次考察共采集和记录实体标本621号,经鉴定共26种(亚种),分隶4目10科18属,其中两栖纲1目2科2属2种,爬行纲3目8科16属22种。其中新疆蟾蜍(Bufo pewzowi)、亚洲林蛙(Rana asiatica)、赛氏沙蜥(Phrynocephalus saidalievi)三个种为优势种类,占总个体数的55.23%;快步麻蜥(Eremias velox)、喜山岩蜥(Laudakia himalayana)、草原蜥(Trapelus agilis)、荒漠无脸蜥(Ablepharus deserti)、施氏石龙子(Eumeces schneideri)、叶城麻蜥(Eremias yarkandensis)、棋斑游蛇(Natrix tessellata)、白条锦蛇(Elaphe dione)、中亚眼镜蛇(Naja oxiana)、四爪陆龟指名亚种(Testudo horsfieldii horsfieldii)11种类为常见种,占总个体数的36.88%;新疆岩蜥(Laudakia stoliczkana)、敏麻蜥(Eremias arguta)、捷蜥蜴(Lacerta agilis)、红沙蠎(Eryx miliaris)、东方沙蠎(Eryx tataricus)、草原蝰(Vipera renardi)等12各种为稀有种类,占总个体数的7.89%。在不同生境间均存在物种多样性指标差异显著(p<0.05),物种多样性在草原最高(2.029 8),其次为山地森林(1.920 4),而荒漠最低(0.233 8);丰富度均在山地森林最高(3.242 51),其次为草原(2.540 0),而在荒漠最低(0.288 5);由于吉尔吉斯斯坦西南部的气候属于典型的大陆性气候,两栖爬行动物物种的组成主要以适应干旱环境的耐旱种类为主,区系组成较为简单,地方种类数量较少,在物种组成及起源等方面与我国西北地区的两栖爬行动物区系有着一定的联系。 相似文献
14.
15.
Mahdi S. Sheraz Dhekale B. S. Jan Rukhsana Bhat M. Anwar Hussain Ashaq Jehangir Intikhab Aalum Sofi Najeebul Rehman Ahmed Latief Qureshi Asif M. Iqbal Aezum Aziz Mujtaba Bangroo Shabir A. Wani Owais Ali Bahar F. A. Mishra S. K. 《Theoretical and Applied Climatology》2022,149(1-2):727-741
Theoretical and Applied Climatology - Analysis of climatic variables is important for the detection and attribution of climate change trends and has received considerable attention from researchers... 相似文献
16.
The transport and leaching potential hazards of various pesticides were studied in a shallow unconfined aquifer located in Northwest Bangladesh. Pesticide leaching potential was quantified using a one-dimensional advective–dispersive transport equation for a non-conservative chemical that follows first-order decay and linear adsorption in soils. Leaching potential index (LPI) was calculated for 69 sites in the study area to evaluate the relative vulnerability to pesticide leaching and to prioritize sites for model study and soil sampling. The numerical ranks of computed LPI were grouped by quantiles into very high, high, moderate, low and very low categories; and based on these rankings, the most vulnerable site was selected. The fate and transport of pesticides in this most vulnerable site was modeled using MT3D. The model results indicate that pesticides with high sorptivity and moderate to high persistence have low potential impact on groundwater. Top soils are found to be particularly vulnerable to the accumulation of organochlorine pesticides. Results also revealed that decreasing the soil organic matter and increasing the half-life of the pesticides at deeper depths did not make any significant change. Finally, six soil samples were collected from the same site at depths of 0.0, 1.5, 3.0, 4.5, 6.0, and 7.5 m for the analysis of pesticide residues. The soil–water was extracted from the samples following standard extraction technique and tested using gas chromatography (GC) and high-performance liquid chromatography (HPLC) for pesticide residues. Results showed no trace of pesticide residues in the soil–water; however, a few unknown peaks were detected indicating the use of some unknown brand of chemicals in the study area. 相似文献
17.
Yanmin Yang De Li Liu Muhuddin Rajin Anwar Heping Zuo Yonghui Yang 《Theoretical and Applied Climatology》2014,115(3-4):391-410
Conceptions encompassing climate change are irreversible rise of atmospheric carbon dioxide (CO2) concentration, increased temperature, and changes in rainfall both in spatial- and temporal-scales worldwide. This will have a major impact on wheat production, particularly if crops are frequently exposed to a sequence, frequency, and intensity of specific weather events like high temperature during growth period. However, the process of wheat response to climate change is complex and compounded by interactions among atmospheric CO2 concentration, climate variables, soil, nutrition, and agronomic management. In this study, we use the Agricultural Production Systems sIMulator (APSIM)-wheat model, driven by statistically downscaled climate projections of 18 global circulation models (GCMs) under the 2007 Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 CO2 emission scenario to examine impact on future wheat yields across key wheat growing regions considering different soil types in New South Wales (NSW) of Australia. The response of wheat yield, yield components, and phenology vary across sites and soil types, but yield is closely related to plant available water capacity (PAWC). Results show a decreasing yield trend during the period of 2021–2040 compared to the baseline period of 1961–1990. Across different wheat-growing regions in NSW, grain yield difference in the future period (2021–2040) over the baseline (1961–1990) varies from +3.4 to ?14.7 %, and in most sites, grain number is decreased, while grain size is increased in future climate. Reduction of wheat yield is mainly due to shorter growth duration, where average flowering and maturing time are advanced by an average of 11 and 12 days, respectively. In general, larger negative impacts of climate change are exhibited in those sites with higher PAWC. Current wheat cultivars with shorter growing season properties are viable in the future climate, but breading for early sowing wheat varieties with longer growing duration will be a desirable adaptation strategy for mitigating the impact of changing climate on wheat yield. 相似文献
18.
Anwar Qadir Zulfiqar Ahmad Tahseenullah Khan Mohammad Zafar Atwar Qadir Mamoru Murata 《Arabian Journal of Geosciences》2016,9(2):149
Dera Ismail Khan (DIK) is situated in the Lower Indus Basin of Pakistan. The land use has been changed in the canal command area due to irrigation activities near the Indus River. To check the current status and predict the groundwater levels in the area, the unconfined aquifer has been simulated in Visual MODFLOW for a period of 35 years, i.e., from 1985 to 2020. The 2900-km2 area has been modeled with a grid of 500 by 500 m and the depth set to 100 m. The aquifer in the study area has been divided vertically and laterally into three and ten zones, respectively, for the characterization. Water wells and streams were used as the sinks and hydrologic boundaries, respectively. The model was successfully calibrated in steady and the non-steady state. The simulation revealed that the whole simulation can be divided into two phases, i.e., before and after the construction of the Chashma Right Bank Canal (CRBC), whereas the results were summarized in the form of water table depth maps and groundwater budget calculations. To determine the groundwater sustainability, a conjunctive use scenario has been employed to simulate the aquifer dynamics till 2020. The simulation revealed incremental drawdowns till the end. 相似文献
19.
In this paper, we analyze higher-dimensional spherical perfect fluid collapse in \(f(R,T)\) theory for minimally coupled models. We use Darmois junction conditions by taking Lemaître-Tolman-Bondi geometry as an interior region and Schwarzschild metric as an exterior spacetime. The solution of field equations is obtained for constant scalar curvature. We determine mass in two regions of the collapsing object and discuss the formation of apparent horizons. We conclude that modified curvature term tends to slow down the collapse rate. 相似文献
20.
为探究绿洲城市道路积尘重金属污染风险,在新疆库尔勒市采集54个代表性道路积尘样品,分析其中Hg、Cd、As、Pb、Cr和Cu等6种元素含量,基于GIS技术与地学统计法,采用污染负荷指数法和US EPA健康风险评价模型,对道路积尘中重金属污染及潜在健康风险进行评价。结果表明:库尔勒市道路积尘中Hg、Cd、As、Pb和Cu等元素含量的平均值均小于土壤环境质量—建设用地土壤污染风险管控标准(GB 36600—2018)中的筛选值,但Cr元素含量平均值为相应筛选值的9.90倍。污染评价结果表明,研究区道路积尘中Cr呈现重度污染,Hg、Cd、As、Pb和Cu呈无污染。道路积尘中重金属元素的污染负荷指数介于0.0142~0.0522,平均值为0.0266,处于无污染水平。从道路积尘重金属污染空间分布格局来看,库尔勒市东北部和北部区域出现污染高值区。健康风险评估结果表明,经手-口摄入途径是库尔勒市道路积尘重金属日均暴露量及健康风险的主要途径,儿童受到的健康风险高于成人。库尔勒市道路积尘中Hg、Cd、As、Pb、Cr与Cu等元素的非致癌风险及致癌风险处于安全范围内,As对非致癌风险的贡献最大,Cr对致癌风险的贡献最大。 相似文献