Geochemistry of rare-earth elements in shallow groundwater,northeastern Guangdong Province,China

Shallow groundwater and hot springs were collected from northeastern Guangdong Province, Southeast China, to determine the concentrations and fractionation patterns of rare-earth elements(REE). The results show that the La, Ce and Nd of REEs are abundant in groundwater and rock samples, and the ∑REE contents in groundwater and rock samples range from 126.5 to 2875.3 ng/L, and 79.44 to 385.85 mg/L, respectively. The shallow groundwater has slightly HREE-enriched PAAS-normalized patterns. However, the granitic rocks PAAS-normalized patterns, with remarkable negative Eu anomalies, are different from that of shallow groundwater. The enrichment of HREE is considered to be controlled by REE complexation and readsorption for most groundwater has Ce and Eu positive anomalies. The Ce and Eu anomalies in groundwater are controlled by redox conditions. Moreover, the Fe-contain sediments dissolution and/or the reduction of Fe oxyhydroxides are another factor contributing to Ce anomalies. The Eu anomalies in groundwater are controlled by the preferential mobilization of Eu2+ during water-rock interaction compared to Eu3+.     

江苏淮扬地区浅层地下水环境质量评价与分析

对淮扬地区浅层地下水环境质量进行了单组分评价和综合评价,分析了各项超标组分的形成机理。评价与分析结果显示:淮扬地区局部浅层地下水水质达不到饮用水标准。生态地质环境背景和人类活动导致该地区浅层地下水中多项指标超标。     

江苏沭阳主城区地质环境质量评价

选取地质条件、人类工程活动、环境地质问题等3 个评价要素和相应的10 个评价因子,建立了沭阳主城区地质环境质量评价体系。利用层次分析法确定了地质环境评价因子的权重,根据模糊数学基本原理确定各评价因子的隶属函数,计算出隶属度,从而建立模糊评价模型,定性与定量相结合对沭阳主城区地质环境质量现状进行了综合评判,将沭阳主城区地质环境质量划分为良好( Ⅱ) 、中等( Ⅲ) 以及差( Ⅳ) 三个区域,评价结果与研究区地质环境现状调查情况基本一致。     

物元分析方法在苏州浅层地下水质量评价中的应用

鉴于水质评价指标的多样性和由单指标给出评价结果的不相容性,在物元分析理论的基础上,将水质量标准、评价指标及其特征值作为物元,建立了基于物元理论的地下水水质评价模型,以苏州市平原区浅层地下水为研究对象,对全区42个浅层水样数据进行水质综合评价,结果表明：研究区南部大部分地区浅层地下水质量优良,在北部和东部一带已遭受严重污染,局部地区水质有从Ⅲ级向Ⅳ级转化的趋势。     

太湖流域某地区浅层地下水有机污染特征

对太湖流域某地区浅层地下水有机污染特征进行了总结,并就污染来源、污染途径和典型污染源附近浅层地下水有机污染特征等问题进行了研究。研究结果表明,该地区浅层地下水中各组分的检出率较高,但检出浓度较低,除苯在个别采样点处超出美国环保局(EPA)饮用水标准外,其余卤代烃和单环芳烃组分均没有超标;平面分布上,卤代烃和单环芳烃各组分的浓度高值点大都集中于该地区东南部的工业区内,这种空间分布特征与工业区的分布具有明显的一致性;垂向上有浅部地下水的污染程度相对较重、深部地下水较轻的特点;典型污染源周边浅层地下水的污染程度较重,但随着采样点远离污染源,地下水中各有机污染组分的浓度迅速衰减。     

信阳市浅层地下水质量评价

为了保护信阳市浅层地下水资源环境,进一步合理开发该区浅层地下水,在对信阳市市区大量浅层地下水水样分析资料的基础上,从饮用水评价,农业灌溉用水评价,工业锅炉用水评价及综合评价等四个方面对该区浅层地下水质量进行了评价。评价结果表明：评价区内虽没有极差的Ⅴ级水,但在人口集中和用水集中的市区均为较差的Ⅳ级水,是人们生产和生活用水质量下降的主要原因;人口集中带来的生活污染是本区浅层地下水主要污染源,次要污染源为工业污染,这些理应引起高度重视,防止污染的进一步扩大。     

江苏高邮地埋管热响应试验及浅层地热能资源评价

为研究江苏高邮浅层地热能资源储量,选取2个典型区块开展现场热响应试验,以线热源理论为建模基础,结合地埋管进出水温度试验数据,建立了典型区块内地埋管热传导模型,采用体积法对研究区浅层地热能资源作出定量评价。数据分析表明：在G001孔处,初始地层温度为17.69 ℃,导热系数为1.389 W/(m·K),钻孔内传热热阻为0.111 K/W,热扩散系数为0.921×10-6 m2/s,热容量为1.508×106J/K,单位延米换热量为104.98 W/m;在G002孔处,初始地层温度为18.58 ℃,导热系数为2.340 W/(m·K),钻孔内传热热阻为0.110 K/W,热扩散系数为0.229×10-6m2/s,热容量为10.200×106J/K,单位延米换热量为163.34 W/m。综上试验参数计算结果可知,区内每年可开发浅层地热能储量至少为6.47×1013kJ。试验设计合理,所得参数真实可靠,可为高邮浅层地埋管地源热泵工程后续设计工作提供基础数据与技术支撑。     

Earth fissures triggered by groundwater withdrawal and coupled by geological structures in Jiangsu Province,China

Earth fissures in Jiangsu Province, China have caused serious damages to properties, farmlands, and infrastructures and adversely affected the local or regional economic development. Under the geological and environmental background in Jiangsu Province, this paper presents the earth fissures caused by excessive groundwater withdrawal and coupled by distinctive geological structures such as Ancient Yellow River Fault in Xuzhou karst area, and Ancient Yangtze River Course and bedrock hills in Suzhou, Wuxi, and Changzhou area. Although all the earth fissures are triggered by groundwater exploitation, the characteristics are strongly affected by the specific geological and hydrogeological settings. In particular, in the water-thirsty Xuzhou city, the cone of depression caused by groundwater extraction enlarged nearly 20 times and the piezometric head of groundwater declined 17 m over a decade. As groundwater is extracted from the shallowly buried karst strata in the Ancient Yellow River Fault zone, the development of earth fissures is highly associated with the development of karstic cavities and sinkholes and their distribution is controlled by the Ancient Yellow River Fault with all the 17 sinkholes on the fault. On the other hand, in the rapidly developing Southern Jiangsu Province, groundwater is mainly pumped from the second confined aquifer in the Quaternary, which is distributed neither homogeneously nor isotropically. The second confined aquifer comprises more than 50 m thick sand over the Ancient Yangtze River Course, but this layer may completely miss on the riverbank and bedrock hills. With a typical drawdown rate of 4–6 m per annum, the piezometric head of groundwater in the second confined aquifer has declined 76 m at Maocunyuan since 1970s and 40 m at Changjing since mid-1980s, and a large land subsidence, e.g., 1,100 mm at Maocunyuan, is triggered. Coupled with the dramatic change of the bedrock topography that was revealed through traditional geological drilling and modern seismic reflection methods, the geological-structure-controlled differential settlement and earth fissures are phenomenal in this area.     

江苏省矿山地质环境质量的模糊评价

矿山地质环境质量评价是一项复杂的系统工作,由于影响因素较多,难以用统一的标准进行度量,至今仍未形成一套标准的评价方法。文章选取影响矿山地质环境的地形地貌、岩土体工程地质性质、开采矿种、开采方式、对自然景观、人文景观及地质遗迹的破坏、对水资源的破坏、占用破坏土地、地质灾害易发程度、地质灾害危害程度、矿产资源开发利用规划、矿山生态恢复治理难易程度等11个因素作为评价因子,应用模糊评价的原理与方法,通过建立模糊数学模型和隶属度矩阵,将江苏省的矿山地质环境质量划分为良好、较好、较差及差4个等级,评价结果为江苏省矿山地质环境保护和整治规划提供了依据。     

江苏丰沛地区浅层地下水氟含量的空间变异与分布特征

在实地调查和采样分析的基础上,运用地质统计学方法,研究了丰沛地区浅层地下水氟含量的空间变异和分布特征。结果表明:丰沛地区62.75%的水样氟含量超过了国家饮用水标准,最大7.11mg/L,平均含量为1.51mg/L。其中39.22%的水样氟含量在1～2mg/L,3.92%的水样氟含量超过4mg/L。丰沛地区浅层地下水氟含量在一定范围内存在空间自相关性,具有明显的各向异性特征。在空间分布上,氟含量总体呈现西北、东南高和东北低的特征,氟含量大于1.00mg/L的面积约占整个研究区域的87.21%,大于2.20mg/L的面积约占12.12%。丰沛地区浅层地下水氟含量超过1.00mg/L的最大概率0.953,其中概率达到0.85以上的为高风险区域,面积297.18km2,占整个研究区的10.81%,主要分布在丰沛地区的西北部和东南部。     

Monotoring shallow groundwater quality in agricultural watersheds in Denmark

Monitoring of shallow groundwater quality is part of the Danish Agricultural Watershed Monitoring Programme. The monitoring program provides fast and field-related information on impacts of changes in agricultural practices on a watershed scale. The monitoring concept described is carried out in six well-defined hydrological basins and includes new types of groundwater nests and soil water stations. Results from the first three years are presented through examples from the clayey till watershed Lillebæk and the sandy watershed Barslund Bæk. By averaging concentrations of solutes in groundwater sampled at the same depth on a monthly basis, it is possible to evaluate trends in the overall impact of climate and different agricultural practices in a watershed on the groundwater quality. Characteristic seasonal variations in nitrate concentrations related to water level fluctuations was observed. The monitoring has demonstrated significantly higher nitrate concentrations in groundwater sampled downgradient of fields receiving manure than in groundwater sampled downgradient of fertilized fields. Significant vertical nitrate reduction downgradient of manured fields was observed in both the sandy and the clayey watershed though above the redoxcline. In the clayey till watershed fast vertical transport and insignificant nitrate reduction was observed downgradient of fertilized fields probably due to fracture and macro-pore flow.     

Geochemical characteristics of shallow groundwater in Datong basin, northwestern China

Located in semi-arid regions of northwestern China, Datong basin is a Quaternary sedimentary basin, where groundwater is the most important source for water supply. It is very important to study groundwater characteristics and hydrogeochemical processes for better management of the groundwater resource. We have identified five geochemical zones of shallow groundwater (between 5 and 80 m) at Datong: A. Leaching Zone (Zone I); B. Converging Zone (Zone II); C. Enriching Zone (Zone III); D. Reducing Zone (Zone IV); E. Oxidizing Zone (Zone V). In Zones I, II, and V and some parts of Zones III and IV, hydrolysis of albite/K-feldspar/chalcedony system and/or albite/K-feldspar/quartz system enhanced concentrations of Na⁺, K⁺, HCO₃⁻ and silicate. In Zone I, dissolution of carbonate and hydrolysis of feldspar generally controlled the groundwater chemistry. Infiltration of meteoric water promoted the formation of HCO₃⁻ in the water. In Zone II, the main geochemical processes influencing the groundwater chemistry were dissolutions of calcite and dolomite, ion exchange and evaporation. In Zones III and IV, in addition to ion exchange, evaporation and precipitation of calcite and dolomite, leaching of NaHCO₃ in saline–alkaline soils dominated the water quality. Zone IV was under anoxic condition, and reduction reactions led to the decrease of SO₄²⁻, NO₃⁻ and occurrence of H₂S, with the highest arsenic content (mean value of 366 μg/L), far exceeding Maximum Contaminant Level (MCL). Abnormal arsenic in the groundwater resulted in endemic disease of waterborne arsenic poisoning among local people. Zone V overlapped Zone I was intensively affected by coal mining activities. Sulfide minerals, such as pyrite, would have been oxidized when exposed to air due to coal mining, which directly added sulfate to groundwater and thus increased SO₄²⁻ concentration. Oxidization of sulfide minerals also decreased pH and promoted dissolutions of calcite and dolomite.     

河北省任丘市浅层地下水化学特征及形成机制

浅层地下水是任丘市重要的水资源之一,为研究其水化学特征及其形成机制,本文在实地调查取样分析化验的基础上,以水文地球化学理论为指导,借助多元数理统计的方法,从多个角度揭示了研究区浅层地下水的形成演化过程:①通过离散分析,认为研究区各主要离子变异系数较大,说明研究区浅层地下水受人为影响明显,水化学特征复杂.②通过相关分析,...     

Tectonic controls on groundwater geochemistry in Hormozgan Province,Southern Iran

Hormozgan Province with arid climate is an important source of energy resources for Iran. This study investigates the results of hydrogeochemical investigation and its tectonic control in Hormozgan Province, Southern Iran. The chemical analysis of 158 groundwater samples was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. Several NW-SE trending and NE-dipping basement reverse faults have intersected the area and have divided it into four tectonic terranes. Huge extension of Hormuz Formation in Zagros Foredeep tectonic terrane has increased the cations, Cl and SO₄ concentration in groundwaters. HCO₃ concentration in Sanandaj-Sirjan Zone and High Zagros is the result of silicate weathering or carbonates. Eighty-three percent of samples have negative CAI values in High Zagros, Sanandaj-Sirjan Zone, and eastern Zagros Fold Thrust Belt. The dominant hydrochemical facies of groundwater are Na-Mg-Ca-Cl (25.3% of samples) and Na-Mg-Cl (20.9% of samples). They are confined to the west of Main Zagros Reverse Fault and east of High Zagros Fault, respectively. The salt content of the groundwater indicates samples with very high salinity—as a result of Hormuz Formation—are mainly limited to the west of High Zagros Fault while samples with high to medium salinity are mainly limited to the east of this fault. Eastward increment of rock weathering is controlled with thrust faults activity of the area and southwestward migration of deformation front. Westward increment of evaporites is compatible with Hormuz Formation/salt dome density through the area.     

安徽省亳州市浅层地下水化学特征及成因机理

安徽省亳州市浅层地下水是当地农业和生活用水的主要来源之一。为查明浅层地下水化学特征、解释其成因机理,文章综合运用描述性统计、相关性分析、离子比例系数和Piper三线图等方法,对143组浅层地下水样品进行分析和评价。研究结果表明亳州市浅层地下水化学类型复杂,主要阳离子含量依次为Na+>Mg2+>Ca2+,主要阴离子含量依次为HCO-3>SO2-4>Cl-;水化学特征主要受水岩相互作用、蒸发等因素影响,大气降水和人为因素总体影响相对较小;水岩相互作用中阳离子交换、硅酸盐和碳酸盐矿物风化溶解是主控因素;人为活动影响中,生活污染、农业活动大于工矿活动影响;地下水质量等级以Ⅳ类水为主,超Ⅲ类水主要影响因子为F-、Na+、总硬度和溶解性总固体(Total dissolved solids,TDS);灌溉水质量以中等为主,主要受Na+浓度过高影响。地下水化学成因机理研究为正在开展的淮河流域地下水资源调查评价和可持续开发利用提供了科学依据。     

苏南下三叠统青龙组碳酸盐岩的成岩作用和孔隙演化

苏南下三叠统青龙组碳酸盐岩中,由于沉积相(台地浅难相和深水斜坡-盆地相)的复杂性,导致了成岩作用和成岩环境的多样性。作者通过薄片观察,阴极发光和碳、氧同位素的分析以及孔隙度、渗透率的研究,对该地区胶结作用、白云石化作用、溶解作用等九种成岩作用进行了详细的讨论,并在此基础上建立了相应的成岩作用和孔隙演化的模式。     

安徽合肥地区浅层地下水质量评价

对合肥地区浅层地下水取样分析, 采用单因子评价法、分类指标评价法和综合评价法对浅层地下水质量进行评价.结果显示:可以直接饮用的地下水资源 (Ⅰ类水、Ⅱ类水和Ⅲ类水) 占59. 3%, 经过适当处理可以饮用的地下水资源 (Ⅳ类水) 占30. 5%, 不能直接饮用的地下水资源 (Ⅴ类水) 占10. 2%.在地下水评价指标中, 挥发性有机指标较好, 毒性重金属指标和半挥发性有机指标次之, 无机毒理指标和一般化学指标较差.影响地下水质量的化学组分主要为铁、锰、总硬度、溶解性总固体、氟、硫酸盐和钠+钾等无机组分, 与人类活动相关的化学组分主要为氨氮、硝酸盐、亚硝酸盐、六价铬、砷、铝、碘、氯化物等无机组分和苯并 (a) 芘等有机组分.影响地下水质量的原因主要为城市和乡镇工业污水、生活污水排放, 农村农药、化肥使用及生活垃圾污染.     

江苏南通地下水补给源、水化学特征及形成机理

在地下水的大规模开采条件下,江苏沿海一带,特别是南通许多地区的地下水一度出现咸化趋势,对区域水资源及环境产生了极大的影响,已成为制约生态环境建设和经济社会发展的重要因素.为查明地下水的补给来源、水化学特征和矿化度增高的机理,对南通地区深浅层地下水开展了野外调查取样.通过对各种水化学参数的讨论分析,系统地研究了该区地下水...     

桂中两江Cu矿床的地质和S-Pb同位素研究

两江Cu矿床为一个位于广西中部的石英脉型矿床。为了查明矿床成因,笔者对该矿床分别进行了矿床地质和S-Pb同位素研究。结果表明,矿石硫化物S同位素的δ34SCDT介于-1.22~0.96‰之间,呈塔式分布,暗示矿石S为岩浆或深部热液起源。矿石Pb同位素的208Pb/204Pb、207Pb/204Pb和206Pb/204Pb的比值分别介于38.698~39.817、15.773~15.879和18.307~19.232之间,平均值分别为39.151、15.809和18.307。对比研究表明,矿石与地层(寒武系和泥盆系)砂页岩和加里东期岩浆岩完全不同的Pb同位素组成,而与晚白垩世岩浆岩(包括昆仑关黑云母花岗岩)具有较为相近分布范围。因此,该矿床的矿石Pb及其成矿金属物质最有可能起源于晚白垩世岩浆作用。结合矿体交截关系和成矿物质来源研究,笔者推测该矿床最有可能形成于晚白垩世。由于含矿石英斑岩为加里东期岩浆作用的产物,因此,在矿区深部存在与成矿作用有成生关系的隐伏岩体,很可能为昆仑关黑云母花岗岩岩基向西北方向延伸部分。区域矿化特征对比表明,大明山W-Cu多金属成矿带深部可能存在矽卡岩型矿化,并预示着巨大的找矿潜力。