Selenium Enrichment in Cambrian Stratabound Gold Deposits in the Western Qinling Mountains

Stratabound gold deposits in the western Qinling Mountains occur in Cambrian chert formation composed of carbonaceous chert and carbonaceous slate. The distinctive chert formation provides important grounds for the mineralization and controls on the formation of gold deposits. Study shows that Se is exceptionally higher in both host rocks and gold orebodies. It may be recovered as a valuable component in ores for total utilization, and in some localities even independent Se orebodies (which are mined exclusively for Se) may be delineated. In gold ore Se mainly occurs as independent minerals or in the isomorphous form in sulphides and there is a positive correlation between Se and Au.     

Selenium and other trace elements in phosphate rock of Bayovar–Sechura (Peru)

Selenium is an essential trace element in regard to human and other animals' health, but it presents a narrow range of dietary deficiency and toxic excess. Some phosphate rocks are rich in selenium. Furthermore it is necessary to control selenium's and other trace elements’ compositions in the phosphate rocks, because phosphorite ores of different geographical sites are varied, and even ores from the same outcrop can vary substantially in trace element levels.     

Selenium contamination in the Colorado River Basin, western USA: Remediation by leaching and nanofiltration membranes

Selenium (Se) is an essential micronutrient to biota, but can become a potent toxicant at elevated concentrations. The natural sources and chemical properties of Se species make the boundary between deficiency and toxicity narrow for some biota, with both…     

Selenium enrichment in Carboniferous Shales,Britain and Ireland: Problem or opportunity for shale gas extraction?

The Carboniferous Bowland Shale in England, and its correlatives in Ireland, contain anomalously high concentrations of trace elements, including selenium (Se), molybdenum (Mo) and arsenic (As). High levels of these elements reflect high sulphur contents as these elements occur as trace constituents of pyrite. Anomalous Se in particular may have a volcanic provenance, from contemporary volcanic activity and/or drainage from Ordovician volcanogenic sulphide deposits. Following concern over the release of Se and As into groundwater during shale gas extraction in the US, the potential fate of Se and As during any future shale gas extraction from the Bowland Shale merits attention. It is at least an environmental issue that must be managed, but at best it could be an opportunity for extraction of Se in an environmentally sensitive manner.     

Geochemical Characters of Selenium，Fluorine and Human Health

通过研究中国土壤、水系沉积物、浅层地下水、粮食、人发中硒和氟的丰度特征，探讨了氧化还原电位、酸碱度等环境参数及母质的元素组分对硒、氟元素迁移、转化、赋存状态的影响，得出硒、氟等不同元素组合与克山病、大骨节病及肝癌等疾病有关的结论。关键词硒氟环境地球化学     

Selenium contamination in the Colorado River Basin, western USA： Remediation by leaching and nanof＇dtration membranes

Selenium （Se） is an essential micronutrient to biota, but can become a potent toxicant at elevated concentrations. The natural sources and chemical properties of Se species make the boundary between deficiency and toxicity narrow for some biota, with both phenomena common around the globe. Large areas of farmland in the Colorado River Basin （CRB） generate salinized drainage water with Se concentrations much higher than 5 μg/L, the U.S. Environmental Protection Agency chronic water-quality criterion for the protection of aquatic life. We have carried out detailed field and laboratory studies to investigate Se geochemistry and remediation in two of these areas： the Middle Green River Basin, Utah and the Salton Sea Basin, California, located respectively in the Upper and Lower CRB. Results from these and other studies show that approximately 90% of the dissolved Se in the Colorado River and its tributaries originally is derived from the Upper Cretaceous Mancos Shale and equivalent pyritic marine units that outcrop in the Upper CRB. Selenium is mobilized commonly by biogeochemical oxidation of this pyritic shale and is concentrated mainly as selenate （SeO4^2-） in soils and agricultural drainage water of dry climates by evaporation. Minor （0%-5%） amounts of Se are present as the selenite species （HSeO3^-） and （SEO3^2-）, but these species and the more reduced species, elemental Se （SeO） and selenide （Se^2-）, have much lower solubility and/or have high sorptive affinity towards organic matter, clay minerals and iron oxyhydroxides. The concentration of dissolved Se （-2.5 μg/L） and salinity in the Lower Colorado River water are among the highest of the world major rivers. Because of low precipitation （7 cm/a） and extreme evapotranspiration （-1.8 m/a） rates in the Salton Sea Basin, California, Se values in irrigation water imported from the Colorado River increase to 〉300 μg/L in drainage wastewater. Removal of Se from contaminated wastewater by nanofiltration membranes was demonstrated in laboratory and pilot-scale field experiments.     

Selenium in soil,grain, human hair and drinking water in relation to esophageal cancer in the Cixian area,Hebei Province,People’s Republic of China

Selenium deficiency was suspected to be a factor in the aetiology of esophageal cancer in the Linxian and Cixian regions of the People’s Republic of China and vitamin trials in the Linxian area indicated that combined supplementation with β-carotene, vitamin E and Se reduced the mortality rate. In order to further evaluate the role of Se, the distribution of total Se in cultivated topsoils, grain, human hair and drinking water was studied in 15 villages in the Cixian area, People’s Republic of China, which in the 1980–1990s had one of the highest mortality rates from esophageal cancer in the world. This study demonstrated that total Se concentrations in drinking water, soil, grain and hair increase from the low esophageal cancer area to the high cancer area, contrary to the expected trend. This suggests that Se deficiency does not play a major role in the aetiology of esophageal cancer in the study area. Nitrate in drinking water is much higher in the area with high esophageal cancer mortality rate than in the low mortality rate area, and this may be a significant factor. Mycotoxins (especially fumonisin), nitrosamine and nitrosamine precursors in grain, ${\mathrm{NO}}_3^{-}$ in drinking water, and dietary β-carotene and Vitamin E remain as potential factors which need to be evaluated further.     

Polymer Particles in Solid Atmospheric Precipitation in the Northwestern Kola Peninsula in 2020‒2021

Doklady Earth Sciences - From December 2020 to April 2021, in the northwestern part of the Kola Peninsula, including the infrastructure of the city of Murmansk, the quantity of polymer particles in...     

Anthropogenic Transformation in Engineering–Geological Megastructures in Russia

Engineering activities lead to the anthropogenic transformation of engineering–geological conditions in different areas of Russia. A differential estimate has been made for changes in individual components of engineering–geological structures: relief, upper section soils, underground waters, depth of seasonal soil freezing and thawing, and current geological processes. The general integrated evaluation of the anthropogenic transformation of engineering–geological megastructures in Russia has been made on the basis of differential estimates of the components.     

Relationship between fluorine content in drinking water and oral health in some big cities in China

Background： Fluorine is an important element to human health. Overloading of fluorine may cause dental and/or skeletal fluorosis, while in fluorine deficiency distracts, fluoride drinking water supply or other methods of fluoridation may greatly reduce the ratio of dental caries of local residents. The benefit of drinking water fluoridation has been widely accepted as a public sanitation measure in most western countries, but in China it faces big challenges. Method： Investigation of oral health and fluorine level in drinking water, main food and urine in some big cities of China. Result and conclusion： （1） Fluorine content in drinking water in 70% of the whole research cities is lower than 0.3 mg/L, and in 90% of the research cities, it is lower than 0.5 mg/L. （2） Fluorine concentrations in main foodstuff of respective cities in China were low and did not have too much difference. （3） Drinking water was the main source of fluorine intake for Chinese residents. （4） With the data of the epidemiological research by NCOH in 1995, in the range of fluorine content in drinking water below 1.0 mg/L, the ratio of dental caries and DMFT decreases with the increase of fluorine concentration. The relation between fluorine concentration in drinking water and dental index did not have a good linear relationship.     

Effects and mechanism of igneous rock on selenium in the tropical soil-rice system in Hainan Province,South China

To illuminate the migration and transformation of selenium(Se)in the igneous rock-soil-rice system,285 pairs of rhizosphere soil and rice samples were collected from the granitoid and basalt areas in Hainan Province,South China.The contents of Se in soils derived from granitoid and basalt are,respectively,0.19±0.12 mg/kg and 0.34±0.39 mg/kg,which are much higher than Se contents in granitoid and basalt.Selenium shows remarkable enrichment from granitoid and basalt to soils.The mobile fraction of Se in soils derived from granitoid is 0.0100±0.0034 mg/kg,which is significantly higher than that of basalt(0.0058±0.0039 mg/kg).Although soil derived from basalt shows higher Se contents,Se contents in rice samples,mobile fractions of Se in soils,and biological concentration factor(BCF)is similar or even lower than that from granitoid.Basalt consist of calcic plagioclase and pyroxene,and are much richer in Fe,Al,and Ca than granitoid.Correspondingly,the basalt-derived soils have higher goethite,hematite,kaolinite,cation exchange capacity(CEC)content,and higher p H than the granitoid-derived soils,which result in higher adsorption capacity for Se and relatively lower Se bioavailability.Soils derived from granitoid and basalt in tropical regions are beneficial to produce Se-rich rice.     

湖北恩施地区土壤-植物系统中Se元素的 地球化学特征

在对恩施地区典型农业活动区——芭蕉、长平和鱼塘坝三地土壤中Se元素含量进行调查的基础上,通过与富Se土壤质量标准进行对比,发现除长平地区外,其余两地分别属于富Se和高Se地区,并通过土壤理化性质、形态分析和土壤中所生长的植物进行比较,初步研究了Se在土壤-植物体系中迁移转化的规律。结果表明：整体来看,鱼塘坝地区属于超富Se地区,植物中Se的含量也最高,长平地区属于非富Se地区,芭蕉地区则属于中等富Se地区;植物对Se的吸收受一定的土壤理化性质的影响,不同类型的植物对Se的吸收富集相差较大;形态分析研究表明,鱼塘坝地区土壤中生物可利用的Se含量较高,而芭蕉地区土壤中残渣态Se的比例较高,表现为Se的生物可利用性低于鱼塘坝地区。     

硒在干酪根中的两种不同赋存状态:TEM证据

对拉尔玛Se—Au矿床和渔塘坝硒矿床中干酪根的高分辨透射电镜(TEM)研究表明，两个矿床的Se在干酪根中的赋存状态是截然不同的。前者Se在干酪根中的富集可能主要以有机结合态的形式存在，主要是取代干酪根中的硫；而后者Se在干酪根中的富集主要以超微包体Se的形式吸附在干酪根中。两种不同的赋存状态可能主要取决于干酪根中硫含量的多少以及成矿时氧化还原条件的变化。研究表明，TEM是研究元素在干酪根中赋存状态的有效手段。     

湖北恩施地区土壤一植物系统中Se元素的地球化学特征

在对恩施地区典型农业活动区——芭蕉、长平和鱼塘坝三地土壤中se元素含量进行调查的基础上,通过与富Se土壤质量标准进行对比,发现除长平地区外,其余两地分别属于富Se和高Se地区,并通过土壤理化性质、形态分析和土壤中所生长的植物进行比较,初步研究了se在土壤一植物体系中迁移转化的规律。结果表明：整体来看,鱼塘坝地区属于超富se地区．植物中se的含量也最高,长平地区属于非富se地区,芭蕉地区则属于中等富se地区;植物对se的吸收受一定的土壤理化性质的影响,不同类型的植物对se的吸收富集相差较大;形态分析研究表明,鱼塘坝地区土壤中生物可利用的se含量较高．而芭蕉地区土壤中残渣态se的比例较高．表现为Se的生物可利用性低于鱼塘坝地区．．     

巴彦淖尔市临河区狼山镇和新华镇一带富硒土壤地球化学特征及影响因素北大核心CSCD

内蒙古自治区巴彦淖尔市临河区狼山镇和新华镇一带发现大面积硒高含量区。为研究该地区富硒土壤的地球化学特征及土壤硒含量的控制因素,采集6250件表层土壤样品,并设计5条土壤垂直剖面进行化学元素测试分析。结果表明,研究区耕地土壤硒含量介于(0.06~0.77)×10^(-6)之间,平均含量为0.32×10^(-6),硒的背景值为0.32×10^(-6),是巴彦淖尔市表层土壤背景值(0.20×10^(-6))和中国土壤背景值(0.20×10^(-6))的1.6倍,且研究区耕地土壤中达到富Se水平(0.4×10^(-6)以上)的样品数为1072个,占全部采样点位的17.2%,表明研究区耕地土壤中硒含量相对较高。研究区土壤中硒和营养元素及重金属元素存在正相关关系,与土壤pH存在一定的负相关关系;硒在土壤垂直方向上分布总体上表现出表聚性特征,随剖面深度增加,硒含量逐渐降低。表层土壤中硒含量主要受土壤有机质含量影响,土壤垂直方向上硒含量主要受有机质与粘土矿物影响。     

乌鲁木齐市某蔬菜基地富硒土壤地球化学特征及生物效应研究

对乌鲁木齐市某蔬菜基地富硒土壤地球化学特征及生物效应分析可知,以硒含量大于等于0.4 mg/kg标准圈定富硒土壤面积约52.89 km^2,硒含量均值为0.78 mg/kg;富硒土壤中重金属元素含量较低,养分元素含量适量丰富,农作物富硒效应较好,安全性较高。通过对土壤中硒元素赋存状态分析,发现区内土壤中存在大量土壤缓效硒,潜在供硒能力较强,且对植物吸收有利的有效硒占比达4.02%;土壤中硒的有效性不仅取决于总硒的含量,还与土壤pH、有机质等有一定关系;农作物中硒的含量水平可能受土壤中有效硒、总硒、有机质、pH等多个因素综合影响。     

黑龙江双阳河流域土壤-作物-人体系统中硒元素及生态环境与人体健康评价

【研究目的】典型黑土地分布区土壤硒自然禀赋、成因来源、生态环境效应及人体健康评价为健康地质研究焦点，开展双阳河流域土壤-作物-人体系统中硒迁移与累积的定量研究，对黑土地富硒农产品开发和地方病防治具有重要意义。【研究方法】测定成土母质、土壤、大气降尘、灌溉水、作物籽实和人发等多介质硒含量，运用GIS、SPSS软件对测试结果统计分析及评价。【研究结果】划定富硒土地46.4 km²，主要沿双阳河及其支流分布；硒以人为成因为主，主要来源于大气降尘补充，输入通量为0.21~1.47 kg/km² · a。土壤、大豆、水稻、玉米和人发硒含量均值为0.305 mg/kg、0.0352 mg/kg、0.0287 mg/kg、0.0198 mg/kg和0.145 mg/kg；作物对土壤硒的富集系数（0.120）远小于1，人发对作物硒的富集系数（4.834）大于1，揭示人发对硒具有较强的浓缩和放大作用，硒在土壤-作物-人体系统中的迁移与积累呈“V”字型模式。【结论】土壤硒含量整体为足硒或富硒，无硒潜在环境风险。大豆、水稻富硒占比为28.4%、9.4%，未发现硒超标情况，无生物硒中毒风险。人发硒含量明显低于参考值0.20~0.60 mg/kg，人体处于缺硒状态，随年龄增长呈递减趋势，可能存在一定的健康风险，应引起地方相关部门关注。创新点：基于系统的生态地球化学数据，运用统计分析学原理，开展典型黑土区土壤-作物-人体系统中硒迁移与积累研究，为富硒农产品开发和地方病防治提供科学依据。     

福建省寿宁县土壤硒分布特征及影响因素

通过福建省寿宁县多目标区域地球化学调查,查明了土壤硒分布和富集特征,研究了土壤硒与pH值及其他元素的相关关系。结果表明,表层土壤硒含量为0.13~0.92 mg/kg,平均值为0.35 mg/kg,深层土壤硒含量为0.14~0.54mg/kg,平均值为0.29 mg/kg,燕山晚期正常花岗岩（ξγK₁）发育的土壤中硒含量最高,平均值为0.39mg/kg,其次为南园组四段（J₃n⁴）和小溪组上段（K₁x²）发育的土壤,不同土壤类型硒平均含量呈现出黄壤 > 红壤 > 水稻土的特点。表层土壤总体上属于富硒、足硒土壤,富硒土壤面积为405.04 km²,占28.24%,表层土壤硒含量相对于深层土壤表现出明显的富集特征,强烈富集区域与富硒土壤区域基本吻合,具有开发富硒农产品的潜力。相关分析表明,土壤硒含量与TOC、Al₂O₃、TFe₂O₃、Mn等呈显著正相关,与pH呈显著负相关,说明土壤理化性质、铁锰氧化物等对硒的表生地球化学行为有重要影响。     

广东省普宁市土壤硒的分布特征及影响因素研究

开展了广东省普宁市区域土壤硒调查研究,采集了413个表层土壤样品(0～20 cm)和103个深层土壤样品(> 150 cm),测定了土壤全硒含量,据此研究土壤硒分布特征及其影响因素。结果表明,普宁市土壤全硒含量变化于0. 16～2. 01 mg/kg,平均值为0. 63 mg/kg,总体上处于中硒及高硒水平,不存在缺硒和硒过剩土壤。砂页岩风化形成的赤红壤全硒含量较高,平均值达0. 86 mg/kg,以侏罗系页岩母质发育的土壤全硒含量最高,平均值达0. 89 mg/kg;三角洲第四系沉积物发育形成的水稻土全硒含量最低,平均值为0. 41 mg/kg。回归分析表明,土壤全硒含量与铁铝含量、有机碳含量具有极显著正相关,与p H呈极显著负相关。影响普宁市土壤硒含量的主要因素是成土母质,土壤p H、有机碳和铁铝含量及土地利用方式对土壤全硒含量分布与富集也有一定的影响。     

浙西典型石煤矿山周边耕地富硒土壤地球化学特征及影响因素

为系统研究石煤矿山周边耕地富硒土壤地球化学特征及影响因素,在浙江省常山县辉埠石煤矿山周边耕地采集了表层土壤样品144件、农产品甘蔗样20件、土壤垂向剖面土壤样6件、岩石样5件和地表水样3件。通过样品Se、有机质、As、Cd、Cu、Pb、Zn、Ni、Hg、Cr等元素含量指标测定和统计,探究了该区富硒土壤地球化学特征。结果表明:区内表层土壤硒含量主要集中于0.47~1.34 mg/kg之间,平均含量0.87 mg/kg,远高于浙江省平均值,且硒含量高值区与辉埠石煤矿的走向一致;硒含量随着土壤深度增加而逐渐下降;89.58%的土壤样品和65%的甘蔗样品达到富硒标准,但存在土壤和农产品Cd等主要重金属元素含量超标的生态风险。土壤硒含量均值在寒武系下统荷塘组最高(1.31 mg/kg),奥陶系中—下统最低(0.64 mg/kg);旱地硒均值略高于水田,但差异不显著(p>0.05);硒含量均值高低变化为粗骨土>石灰岩土>水稻土>红壤。研究认为,土壤硒含量受地质背景、土壤类型和有机质等因素的影响,含石煤层黑色岩系和碳酸盐岩等富硒地层是形成富硒土壤的主要因素,小部分与矿山开采等人类活动有关。