Geogenic Imprint on Groundwater and Its Quality in Parts of the Mamfe Basin, Manyu Division, Cameroon

Groundwater studies in parts of the Mamfe basin are sparse and the Mamfe area has the highest population density in the Mamfe basin. An in-depth study of groundwater rock interaction and groundwater quality is of vital importance. This same part of the basin is the economic centre and as such development of businesses in this area requires knowledge of the groundwater quality. Therefore, this study was undertaken to determine the input of the rock formations on the groundwater solute chemistry and groundwater domestic-agro-industrial quality using hydrogeochemical tools and physicochemical parameters: Ionic ratios, Gibbs diagrams, Piper diagrams, Durov diagrams and water quality indices. From physicochemical parameters, in the rainy season, pH ranged from, 4.3 - 8.6;EC, 3 - 1348 μS/cm;Temperature, 24.4℃ - 30.1℃? andTDS, 2.01 - 903.16 mg/L and in the dry season, pH ranged from 5.5 - 9.3;EC, 6 - 994 μS/cm;Temperature, 25℃?- 38.6℃?andTDS, 4.02 - 632.48 mg/L. Forty groundwater samples: 20 per season, wet and dry were analysed. The major ions fell below WHO acceptable limits for both seasons. The sequences of abundance of major ions were: Ca2+ > K+ > Mg2+ > ?> Na+, Cl- > ?> ?> ?> NO3 in wet season and Ca2+ > Mg2+ > K+ > Na+, ?> Cl- > ?> ?> ?in dry season. Ion-exchange, simple dissolution and uncommon dissolution processes determined groundwater character. Groundwater ionic content was as a result of ion exchange from rock-weathering. Water types are: CaSO4 and MgHCO3 in both seasons. Hydrogeochemical facies are Ca-Mg-Cl-SO4 and Ca-Mg-HCO3. SAR for wet season 0.05 - 0.06 and dry season 0.00 - 0.05, %Na wet season 3.64 - 16.59 and dry season 1.22 - 10.97, KR wet season 0.01 - 0.02 and 0.00 <span style="font-size:10pt;

Application of Multivariate Statistic of U, Th and Pb Concentrations and Pb Isotopic Signatures in the Assessment of Geogenic and Anthropogenic Sources in a U-Mineralized Area

This work presents a Principal Component Analysis (PCA) study using Pbisotope signatures and U, Th and Pb concentrations from groundwater, sediments and rocks (granites and orthogneisses) of the Complex of Lagoa Real (Bahia, Brazil). This area is naturally enriched in U and Th, with the occurrence of Pb derived from the radioactive decay of the elements (238U, 235U and 232Th) in the form of their stable isotopes 206Pb, 207Pb and 208Pb in addition to the natural isotope 204Pb. Sampling was carried out in the rainy season (December to January) and the points were selected according to regional hydrology and geology. Thirty samples were analyzed: 12 of groundwater (AP) and 18 of sediments (S). The results show that the use of isotopic ratios allows discrimination between geogenic and anthropogenic samples. This information is not obtained using only the analysis of concentration data. Statistically, the isotopic data of Pb stand out as an efficient tool in the characterization of sources in the scenario investigated, allowing an effective environmental monitoring and a better management of the mining activities.

Geogenic versus Anthropogenic Metals and Metalloids

Developing a successful strategy for investigating and remediating sites potentially impacted by metals (such as chromium [Cr], copper [Cu], lead [Pb], nickel [Ni], and zinc [Zn]) and metalloids (such as arsenic [As] and antimony [Sb]) can be challenging. These elements occur naturally and geologic materials can be enriched in these elements by natural processes. Conventional environmental investigative methods do not readily support evaluating whether metals and metalloids are geogenic (naturally occurring) or anthropogenic (from human action), or allow differentiating multiple anthropogenic sources. Geochemical methods can potentially determine whether metals and metalloids are geogenic or anthropogenic, and differentiate between possible anthropogenic sources. Conventional geo-chemical methods include whole-rock analysis using x-ray fluorescence (XRF) to yield elemental concentrations;optical petrography and powder x-ray diffraction (XRD) to determine mineral phases present;and electron microprobe (EMP) to confirm both mineral phases present and the distribution of elements within mineral phases and the rock matrix. These methods, with the exception of the EMP, can be performed in the field using portable equipment, allowing for relatively rapid assessment of sites. A case study is presented in which these techniques were successfully utilized to demonstrate, using multiple lines of evidence, that metals and metalloids present in subsurface fractured rock were geogenic and unrelated to recent industrial operations.

长江中下游湖泊沉积物铅污染记录——以洪湖、固城湖和太湖为例

2002～2005年在长江中下游的洪湖、固城湖和太湖分别采集了沉积物柱样钻孔，测定了总有机碳（TOC）和金属元素包括Ph，Al，Fe，Ti等，并采用210Pb和137Cs进行了近代沉积物定年。研究结果表明，洪湖钻孔平均沉积速率为0．15cm／a，固城湖平均沉积速率在0．067cm／a，太湖平均沉积速率为0．35～0．41cm／a。根据湖泊沉积物中铅元素与参考元素（Al，Fe和Ti）浓度和TOC的相关关系建立了回归方程，线性关系极显著（P〈0．001）。根据回归方程获取了钻孔中铅的背景值变化，研究表明近代沉积物中金属铅不仅仅来源于自然的作用，而人类活动导致铅的累积发生时间都在20世纪70年代，从一个侧面也说明利用沉积物铅含量变化进行断代存在可能性。对太湖钻孔而言，其污染程度要高于洪湖和固城湖。研究结果表明近30年来洪湖和固城湖人为造成湖泊沉积物铅累积量在不断增加，其沉积物铅污染有进一步加重的趋势，应受到科学家和管理部门的关注。

典型岩溶地质高背景土壤镉生物有效性及其控制因素研究

我国岩溶地貌主要分布在广西、贵州、云南等西南地区,全国土壤污染状况调查公报显示这些岩溶区土壤中金属元素通常超标严重,其生物有效性的相关研究仍较缺乏.采集广西典型岩溶重金属地质高背景地区的稻田土壤,分析金属元素As,Cd,Cr,Cu,Ni,Pb和Zn总量,并采用CaCl2和EDTA(Ethylene Diamine Tetraacetic Acid)提取方法分析土壤中金属的生物有效态含量.结果表明,与上部地壳相比,研究区土壤中不同重金属的富集程度顺序为Cd>As>Pb>Zn>Cr>Cu>Ni,与广西灰岩中这些重金属的富集程度顺序基本一致,揭示岩溶区地质高背景土壤重金属的富集具有显著的母岩继承性.土壤Cd的CaCl2提取的平均含量为0.02mg·kg-1,平均提取率为4.37%,远低于人为污染区土壤Cd的CaCl2提取的平均含量和提取率.EDTA提取态Cd的含量平均值为0.84mg·kg-1,平均提取率为52.86%.岩溶区土壤Cd的CaCl2提取态含量与土壤Cd总量没有明显的线性关系,生物有效性和生态风险主要受pH控制:当土壤pH>6.5时,虽然土壤Cd总量较高,但CaCl2提取态Cd含量偏低,生态风险低;而当土壤pH<6.5,土壤Cd总量相对偏低时,CaCl2提取态Cd含量较高,生态风险较高。

地质成因的甲烷释放对大气的影响

地质成因自然源的甲烷释放在整个大气甲烷估算中起着非常重要的作用,它既是不含放射性14C甲烷源(死碳源)缺失部分的重要代表,也是甲烷重碳源的重要部分。概述了国内外关于地质成因甲烷释放对大气甲烷源与汇影响的研究进展,详述了来自地质成因化石燃料泄漏的人为甲烷释放以及来自沉积盆地(含油气盆地)、泥火山、地热区、海洋和甲烷水合物的地质自然源甲烷释放对大气甲烷源与汇的贡献及其影响因素;说明由于地质成因甲烷分布的区域性、不均匀性和时空的高度变化性,以及目前地质成因甲烷的通量估算仅建立在区域性的少量甲烷通量测试基础上,造成了地质成因甲烷释放通量估算的高度不确定性;指出研究中国西北地区油气田集聚区的甲烷释放通量,对油气田地质成因甲烷释放通量的估算具有重要意义。

含油气盆地地质甲烷释放研究综述

目前地质甲烷在国际上引起了广泛的关注。地质甲烷的释放在整个大气甲烷的源与汇的研究具有重要的意义。它既为不含放射性^(14)C甲烷源缺失部分提供了可能的解释,也为全球气候变暖的研究提供了科学依据。含油气盆地的甲烷是地质甲烷中的重要组成部分。本文概述了国内外含油气盆地甲烷释放的研究,详述了含油气盆地甲烷的源以及运移机制;阐述了目前对于地质甲烷研究的常用监测手段及其优缺点;并对全球含油气盆地的甲烷通量估算进行了总结。但是由于含油气盆地甲烷的通量估算是建立在区域性的部分甲烷通量测试基础上,仍然具有较大的不确定性。有效地结合甲烷的各种监测手段,在全球更多更广区域开展含油气盆地CH_4通量测量,是未来的发展方向和热点。我国是油气生产的大国之一,但相关的探究很少,因此,在我国开展含油气盆地甲烷释放通量的研究将有助于进一步完善全球含油气盆地甲烷数据库,对全球甲烷的源和汇的精确估算具有重要作用和意义。

瑞士饮用水安全保障技术措施:检测、处理与保护

饮用水安全一直是全球关注的一项重要议题。检测手段的低时效性、地球成因污染物的存在以及微污染物的出现对饮用水安全造成了很大的威胁。为此,瑞士Eawag研究人员采用基于流式细胞术的微生物检测手段,对水中的微生物进行了快速、准确的定量检测,并对地球成因污染物及微污染物的去除方法及工艺进行了有益的探索。此外,还对与地下水保护密切相关的河水补给地下水行进时间及所占地下水水量比例的确定方法进行了阐述。

Achieving Sustainable Use and Management of Water Resources for Irrigation in Nigeria

Water resource is available in Nigeria to meet water demand for domestic,agricultural and industrial use.If well enhanced and protected from various source of pollution.However,less information is available on suitability of water resources for irrigation use in Nigeria.This article reviews literature of the past with regards to influence of geogenic and anthropogenic activities on water resource for irrigation purpose in Nigeria and also to explain the current state of suitability of water resource for irrigation studies in Nigeria and gaps in studies.It also summarizes future ways on water resource management and preventive measure for water resource pollution for irrigation use.Related articles were downloaded from Google scholar in water-related issues.This paper tends to review previous article on water resource in Nigeria,and its suitability for irrigation.The primary aim of this paper is to produce a synoptic overview of the water resources in Nigeria and its suitability for irrigation use.From paper reviewed it was observed that 89%of water resources was considered suitable for irrigation.

A Comprehensive Review of Water Quality Monitoring and Assess­ment in Delta State,Southern Part of Nigeria

This research presents a review on water resources in Delta state,south­ern part of Nigeria,with emphasis on hydrogeochemical and microbial assessment.It evaluates factors responsible for water contamination,and their resulting health challenges within the study area.To achieve the ob­jective of this study,related articles were downloaded from Google,pub­lished article on influence of hydrogeochemical and microbial activities on water resources.These articles were thoroughly studied.Findings from this study,suggested that groundwater was more studied than surface wa­ter.We also observed that groundwater within the riverine communities is much more prone to pollution when compared to groundwater in an up­land area.Results from various authors suggested that,larger percentage of groundwater showed presence of coliform.Further findings suggested that geochemical processes such as rock water interaction,seawater in­trusion and precipitation influences groundwater quality within the study area especially within Sombreiro-Warri Deltaic Plain Deposit.

典型黑色岩系分布区土壤重金属污染与生物有效性研究

风化作用条件下,黑色页岩富含的重金属元素释放到环境中,会引起土壤重金属污染。运用生态地球化学的分析手段,对发育于浙江寒武系黑色页岩地层(荷塘组)土壤的重金属污染现状、来源、分布特征及其生物有效性进行系统研究。结果表明,研究区土壤重金属Cd、As、Cu、Zn和Hg均存在超标现象,超标率分别为67.81%、7.81%、7.18%、4.68%和1.87%;而Se、Ni、Pb和Cr等未超标;对黑色页岩和土壤重金属分布特征进行分析可知,超标土壤分布区域与黑色页岩发育区域基本吻合,土壤中Cd、Cu、Se、Ni、Zn等重金属主要来源于黑色页岩风化释放;土壤重金属的生物有效性因来源不同而差异显著,其生物可利用率顺序为Cd>Zn>Se>Ni>As>Pb>Cu>Cr;Cd等元素的高生物可利用率对当地生态环境产生潜在的危险。

Sanitary Surveys and Hydrochemistry of Groundwater in Two Urban Towns (Ado-Ekiti and Ijero-Ekiti), Southwestern Nigeria

Groundwater contamination in urban cities is imminent in the phase of increased anthropogenic activities apart from the contribution of geogenic contaminants. This study examined the sanitary surveys and hydrochemistry of groundwater in Ado-Ekiti and Ijero-Ekiti to establish the contaminants’ sources, decipher the effects of urbanization on population and explain any relationship between the surveys and the groundwater chemistry. Sanitary surveys of 30 randomly selected wells each from Ado-Ekiti and Ijero-Ekiti were executed by administering and processing appropriately designed questionnaires that addressed salient problems of hygiene and sanitation. The results of the surveys were grouped into very high risk, high risk, intermediate risk, and low risk classes. Subsequently, at each location, in situ parameters (temperature (°C), pH and EC (μS/cm)) were measured using a portable Multi-parameter TestrTM 35 Series S/N: 1382654. At each well, water samples were collected into clean polyethylene bottles in triplicates for cation, anions and e-coli evaluations, respectively. Water samples for cations were acidified by adding two drops of concentrated nitric acid. All samples were kept in a refrigerator at a low temperature of about 4°C before being taken to the Federal University of Technology, Akure, for analyses. Ion chromatography was employed for the anions analysis while the cations were determined using an Atomic Absorption Spectrophotometer Buck 210 model. Membrane filter technique was employed for the e-coli estimation. From the results of the hydrochemistry, the Nitrate Pollution Index (NPI) and Modified Nitrate Pollution Index (MNPI) were estimated and classified into;clean unpolluted, light pollution, moderate pollution, significant pollution, very significant pollution waters. Sanitary surveys in the two cities showed that in the very low risk, intermediate and high-risk categories, Ado-Ekiti had 33.33%, 56.67% and 10% representations, while Ijero-Ekiti had 50%, 23.33% and 26.67% representations, respectively. This observation showed that Ado-Ekiti with higher population and humans’ activities compared to Ijero-Ekiti was less susceptible to pollution. Urbanization has no direct effects on sanitary surveys. The pH of wells’ water in Ado-Ekiti ranged from 4.8 - 8.2, EC (μS/cm) from 101 - 1008, while at Ijero-Ekiti, the pH and EC (μS/cm) varied from 2.1 - 13.8 and 80 - 1008 respectively. Ado-Ekiti wells’ water was more acidic than that of Ijero-Ekiti. Chemical concentrations (mg/L) of Ca2+, Mg2+, Na+, K+, , and Clˉ of the wells’ water in both cities were within WHO-approved standards for drinking water. However, with average concentrations of 142.17 (mg/L) and 252.71 (mg/L) at Ado-Ekiti and Ijero-Ekiti, respectively, exceeded the standard in many locations. Susceptibility to pollution classification employing TDS, NPI and MNPI showed that Ijero-Ekiti was more susceptible to pollution compared to Ado-Ekiti. This assertion was supported by statistical analysis employing correlation, cluster analysis, and principal component analysis. This study showed that urbanization had no direct effects on sanitary surveys and groundwater quality. Pollution of wells’ water in the two cities was, mainly from anthropogenic activities. However, Ijero-Ekiti, with significant anthropogenic activities, had its wells’ water more susceptible to pollution. Sanitary surveys are a complementary method to water quality monitoring.

印度史诗《摩诃婆罗多》成因考论——基于印度地理环境与社会历史的分析

世界著名史诗《摩诃婆罗多》与印度地理环境及其历史文化关系密切。史诗的生成离不开印度独特的地理环境,其对印度自然风光的多处描写形成独特的审美意蕴;史诗文本呈现的"深刻而糊涂"这一特点也是印度先民思维特征之反映。《摩诃婆罗多》的生成鲜明表征了马克思主义"社会存在决定社会意识"这一基本原理。

Comparative Assessment of Heavy Metals Pollution in Surface Water in Ikoli River and Epie Creek in Yenagoa Metropolis Using Geographical Information System

The article is the investigation of heavy metals pollution on surface water in Ikoli River and Epie creek in Yenagoa,metropolis,Bayelsa State.Pb,Cd,Ni,Cr,Fe,Zn was determined and evaluated using Geographical Information System.Zinc concentration was below the permissible limit of 3 mg/L in all the locations sampled.Iron is 77.78%below the limit of WHO 2011 of 0.3 mg/L while other heavy metals examined in Ikoli River and Epie creek are highly polluted.The pollution index for contamination index shows 11.11%sample are high and 88.89%are low while the evaluation of heavy metal index and the pollution index load of the heavy metals contain 22.11%of the sample are low and 77.78%are high which imply the Ikoli River and Epie creek is polluted.Multivariate treatment of the result revealed a good correlation between the PCA and HCA,which showed activities of natural processes and man influenced environmental sources of the heavy metals which were mainly products of automobiles exhaust,water tank leakages as well as dumping of radioactive wastes and burning.The study investigated successfully the potential use of GIS with the help of multiple criteria decision analysis to predict and characterize areas of high pollution,medium,and low pollution in the study area.

黑色岩系地质高背景区土壤锌富集特征与环境活性

锌(Zn)既是生物体必需元素又是有害元素,在复合污染的情况下,Zn在植物吸收、转运和富集镉的过程中发挥着重要作用。以往研究主要关注镉的活性,忽略了Zn的环境活性。基于此,本研究以黑色岩系地质高背景区自然富Zn土壤为对象,重点研究了土壤Zn的活性态和潜在活性态,讨论了Zn活性的影响因素和环境意义。结果表明,研究区土壤Zn富集,平均含量可达457 mg/kg,80%的土壤样品超过我国农用地土壤污染风险筛选值。CaCl_(2)提取态Zn含量平均值为0.92 mg/kg,平均提取率仅为0.26%,说明研究区土壤Zn的生物活性低,且随着pH升高而降低。EDTA提取态Zn的平均含量为12.7 mg/kg,平均提取率为2.74%,潜在有效态比例也较低。活性态在潜在活性态中占比为7.63%,活化潜力较大,且随着土壤pH的升高而降低。研究区土壤溶液中Zn∶Cd比较低,可能有利于植物对镉的吸收。开展土壤Zn活性的研究,对理解复合污染区土壤镉的活性变化及调控具有重要意义。

Metal contamination assessment in the urban stream sediments and tributaries of coastal area southwest Nigeria

A geochemical assessment of the fifty surface stream sediments from Ikorodu Southwest Nigeria was carried out to determine the level of contamination. The sediments were dried, disaggregated and sieved to \75 lm fraction for geochemical analysis, using the aqua-regia digestion technique and inductively coupled plasma mass spectrometry. Major elements showed the following trend Fe [ Al [ Ca [ Na [ Mg [ K [ P [ Ti and were below the average shale concentration, except for Na in one sample.Results from factor and correlation analyses showed two groups of trace elements Ni, Co, Mn, U, Th, Sr, V, La, Cr, Ba,Sc, Ga, Cs, Nb, Rb, Y,Ce and Mo, Pb, Zn, As, Cd, Sb, Sn, Zr,which were from geogenic and anthropogenic sources, respectively. The enrichment factor showed that Cd, Bi, Pt, Mo and Ag were, for all samples, within background concentrations, except those of the Ogun River and the Owode Onirin, which showed significant enrichment of Cd, Zn, Cu,Pb and Ag, depletion to minimal enrichment for Bi, Mo and moderate enrichment for Pt. The contamination degree ranged between 1.25 and 143.79. The highest value was found at Owode Onirin and the lowest, at Igbonla 7. The geoaccumulation index showed that all the stream sediments ranged between practically uncontaminated to moderately to highly contaminated—with Pb, Sn, Zn, Cd, Cu, Cr, Zr and Ba. The potential ecological risk factor and environmental risk index(IER) showed that all of the samples were within the class of low to medium contamination risk, except samples from the Owode Onirin, which fell within the class of very high risk to extremely high risk respectively.

基于树的机器学习方法预测地质成因劣质地下水空间分布

截止到2020年,全球78亿人中仍有20亿人无法获得或只能获得有限的安全饮用水。地质成因劣质地下水(GCG)的广泛存在是造成这种严酷现实的重要原因之一,因此识别GCG已成为全球关注的热点。近年来,基于树的机器学习方法不仅成为揭示GCG空间分布和防范公共健康风险的有力工具,而且能帮助我们更好地理解地下水中劣质组分的水文生物地球化学行为。为促进基于树的机器学习方法在水文地质尤其是地下水水质与健康领域更为广泛的运用,综述了近20年来分类和回归树、随机森林和增强回归树等基于树的机器学习方法在GCG研究中的应用,讨论了如何应对正确优化模型超参数、细心选择强有力的预测变量和合理评估模型性能等诸多挑战。

基于极端梯度提升模型预测江汉平原高碘地下水的空间分布

长期摄入高碘地下水(碘浓度>100μg/L)会造成人体甲状腺机能损伤,掌握区域高碘地下水的空间分布规律对于有效规避劣质地下水,保障地下水资源的可持续安全供给至关重要。但大规模地下水水质调查耗费大量的人力、财力、物力。基于江汉平原177组常规的浅层地下水水质调查数据,选取DOC、HCO^(-)_(3)、Mg^(2+)、Fe^(2+)、NH^(+)_(4)-N、SO_(4)^(2-)等水质参数作为预测变量,建立江汉平原高碘地下水风险极端梯度提升机器学习预测模型,用于预测研究区高碘地下水的空间分布。结果表明:该模型通过测试数据集检验,预测的准确率达到86.4%;模型预测结果显示,江汉平原高碘地下水主要分布在长江河曲沿岸,零星分布在平原腹地河湖区,并识别出江汉平原西北部丘陵前缘的汉江沿岸也是高碘地下水分布的潜在区域。该研究结果将有助于圈划高碘地下水的空间分布范围,可为确定未来地下水水质监测的优先区域提供科学指导。

沈从文湘西小说中的地缘道德景观

沈从文湘西小说整体上呈现出一道建立在区域文化历史演变和作者文学虚构双重基础之上的地缘道德景观。在这个宏大叙事结构内,地貌变化和文化、道德面貌变化存在着系统对应:从西部高山的苗族部落文化到河谷丘陵地带的汉苗混合文化,再到沅江下游的汉族儒家封建文化,随着地势的递减,社会道德相应堕落。湘西小说所描绘的汉苗对照、城乡对立受此总体格局的影响。纵向看,湘西小说继承发扬了中国悠久的地缘思维传统;横向看,沈从文作品同20世纪初兴起的西方现代主义遥相呼应,显示出同五四新文学主流迥异的文学趣味和品格。总体上,湘西小说表现出共时性或历史空间化、多元杂糅性、包容性和延展性、单篇作品相对独立性和各篇章之间的关联互动性、传统性,以及包括现代主义的现代性等特点。湘西小说还带有鲜明的地缘文化政治的色彩,是沈从文建构个人文化身份的重要方式。