Environmental toxicology and exposure to natural dust： The role of trace elements

This discussion reviews environmental toxicology and health effects of trace elements and compounds carried in natural dusts of geologic or geochemical origin. The sources of these dusts are diverse, including volcanoes, dust storms, long-range transport of desert dust, and displacement through natural processes such as landslides and earthquakes. Estimates diverge greatly in terms of the total quantities of dust transported, although recent papers place annual volumes at over 1 billion tons from the main African deserts alone. Anthropogenic influences （such as from farming and irrigation） have contributed to dust formation by enhancing the process of desertification, with losses of over 10 million hectares （~29 million acres） of farmland per year. The principal elements and compounds which are examined in this presentation are trace metals and metalloids, radioactive elements, fluoride, silicates, natural asbestiform compounds, and alkali salts. The pathways by which such agents affect human populations are examined, including carriage through water, air, soil and the foodchain. The mechanisms of biotoxicity, and the acute and chronic consequences on health, associated with toxic trace metals are described.     

High resolution profiles of trace metals in pore waters of marine and riverine sediments assessed by DET and DGT

In polluted aquatic systems, toxic metals are often accumulated in bottom sediments. They are, however, not necessarily stored definitively because diagenetic processs can modify redox, pH and even the amount of complexing ligands, releasing the trace metals back into the pore waters and the water column. Especially the labile metal fraction in the pore waters is important since this is the bioavailable fraction determining the bio-toxicity of the sediments. The goal of our study was therefore to assess, with novel sampling techniques, this bioavailable metal fraction in the pore waters as well as the flux towards the overlying water column. High-resolution profiles of trace metals in pore waters of marine and riverine sediments were assessed by DET （diffusive equilibrium in thin films） and DGT （diffusive gradients in thin films） gel techniques. The DET technique uses a diffusive gel layer that equilibrates with the aquatic system and with this technique the concentrations of total dissolved trace metals are obtained directly. The DGT technique uses an acrylamide diffusive gel backed by a resin gel （Chelex） which binds trace metals. With the DGT technique only labile species of selected metals can be captured. According to the redox potential measurements, the marine sediments were suboxic （200 mV to -220 mV versus Ag/AgCl electrode）, while the riverine sediments were completely anoxic （-160 mV to -220 mV versus Ag/AgCl electrode）. This redox potential was apparently controlling the trace metals species in the pore waters： for example a strong correlation between Mn and Co was found in the riverine sediments （for DET and DGT sampling）, while in the marine sediments trace metals presented various behaviors.     

Contamination and bioavailability of heavy metals in sediments from the Yangtze River Delta Region

The Yangtze River Delta Region is one of the most important economic development areas in China. In the process of its industrialization and urbanization, a great deal of wastewater is poured into rivers, lakes and coasts. Researches on contamination and bioavailability of heavy metals can help us to assess the ecological risks in the aquatic environment of the Yangtze River Delta. The samples were collected from three environmental compartments including the Yangtze River, Taihu Lake, and the south coast of Jiangsu. The concentrations of heavy metals were determined by ICP-MS. Metal speciation was determined by the sequential extraction procedure modified based on Tessier＇s scheme. Among the seven elements of Cu, Pb, Zn, Cr, Cd, Co, Ni detected, the contents of Cr, Zn did not vary significantly, while Cd and Pb varied significantly. Compared to the background values （loess in the basement）, all metals detected except Co, Cr exceeded the background level. Cd had the greatest exceeding values, reaching 2 to 7 times. Ni and Pb were followed. The contents of Zn were comparatively high in lake sediments, especially in the lake bays. Ni was enriched in fiver sediments and Cu was highest in sediments from the Yangtze River estuary. Cd and Pb were concentrated in the coastal sediments. Comparatively, in space, Cr was associated with the carbonate fractions in the bay of lake. Cu-bound Fe-Mn oxides and Ni in residual form were highest in the open lake. In the river environment, Fe/Mn oxide-bound Pb, exchangeable Cd were the highest fractions. In the estuary environment, Pb and Zn bound carbonates, Cd-bound Fe-Mn oxides are the largest fractions. Cd in the exchangeable fraction, Cu-bound Fe-Mn oxides had the larger proportions in the coast. In general, the bioavailability of Cu and Cd were high in lake environment, the available Pb, Cd were remarked in river environment, and Pb and Zn were easily assimilated by creatures in estuary.     

Genesis of Neogene Formation Waters in the Central Qaidam Basin: Clues from Hydrochemistry and Stable D-O-S-Sr Isotopes

Geological explorations have revealed plentiful Neogene formation waters in anticlines in the central Qaidam Basin (QB). However, the hydrochemistry and origin of these waters are obscure. In this study, the hydrochemistry and D-O-S-Sr isotopes of these formation waters were determined to study their origin and evolution. The formation waters are enriched in Na-Ca-Cl, and depleted in Mg-K-SO4-HCO3 ions with elevated Li-B-Br-Sr elements. The D-O isotopes prove that the formation waters originated from weak-evaporated meteoric waters, and experienced water-rock interactions. Ion comparisons and Caexcess–Nadeficit diagrams suggest that solute sources of these waters include evaporite dissolution, water-rock interaction, and minor residual lake brines. Bacterial sulfate reduction and water-rock interactions are supported by the high S-Sr isotopes. The enriched Li-B-Br-Sr concentrations of these waters are in accord with the high geochemical background values of the QB. Regarding the genesis of the formation waters, it can be concluded that meteoric waters from the southern Kunlun Mountains were discharged into the basin, weakly evaporated, and then infiltrated into the Neogene strata through faults leaching the soluble ions and mixing with residual lake brines, and all experienced water–rock interactions and a sulphate reduction process.     

A Preliminary Study on Dust Grains in the Stratosphere

Collected by means of a high-altitude scientific balloon and a self-made automatic sample collector,a total of 276 dust grains were selected for the study of shape,grain size and optical property.Some of the grains were examined by X-ray diffraction and electrom microprobe techniques,The stratospheric dust grains can be classified as 6 types:cosmic dusts,cosmic dusts(?),microtektite,natural pollutants,artificial pollutants and the unknown substances.The different types of dust grains have different characters and distinguishing symbols.Widespread in the space of the solar system,cosmic dusts are the initial substances of the solar system and ,to some degree,have recorded a great wealth of information on the early history of the solar system.So they have become one of the important objects in the field of cosmochemistry at present time,Since the 1960‘s,scholars of many countries have collected cosmic dusts both in the space near the earth(using rock ets,space probes and space shuttles)and in the stratosphere (using high-altitude balloons or U-2air planes).According to the shape(the scanning electron microimage),element composition(the energy-dispersive X-ray spectrum)and optical properties of dust grains,the substances in the stratosphere can be classified as 5 types:cosmic dusts,alumina spheroids,terrestrial artificial pollutants,terrestrial natural pollutants and unknown substances(CDPET,1982).     

Mineralogy and Geochemistry of Major,Trace and Rare Earth Elements in Sediments of the Hypersaline Urmia Salt Lake,Iran

Urmia Salt Lake(USL) is a hypersaline lake located at the NW corner of the Iran platform. The lake area is estimated to have been over 5000 km~2 at one point, but has now decreased to 1000 km~2 in the last two decades. It contains 4.6×10~9 tons of halite and other detrital and evaporative minerals such as calcite, aragonite, dolomite, quartz, feldspars, augite and sylvite. This study examined the mineralogy and geochemistry of bed sediments along the mid-east toward NE bank sediments collected from 1.5 meters depth and nearby augite placer. Due to the diverse lithology of the surrounding geology, bed sediments vary from felsic in the mid-east to mafic in the northeast. Weathering of tephrite and adakite rocks of the Islamic Island at the immediate boundary has produced a large volume of augite placer over a 40 km length, parallel to the shoreline. Based on the study result, weathering increases from south to north and the geochemistry of the sediments shows enrichment of Mg O, Ca O, Sr and Ba associated with Sr deployment in all samples. Rare earth elements(REE) patterns normalized to the upper continental crust(UCC) indicated LREEs enrichment compared to HREEs with an elevated anomaly of Eu, possibly due to surface absorbance of Mn and Fe minerals, associated with Sr elevation originating from adakites in the lake basin vicinity.     

Polychlorinated biphenyls in the Nanshan Underground River, China

Abstract Karst areas have much higher ecological vulnerability and are easy to be contaminated by polychlorinated biphenyls(PCBs) which are introduced as health risk pollutants.PCBs concentrations were used to understand the transport behavior of PCBs conducted in the karst Nanshan Underground River,China.Water and sediments from the underground river water,and sediments and soil from the surface of the corresponding watershed were collected monthly in 2011 and 2012 and PCBs were analyzed.Seasonal variations were found in concentrations of PCBs both in the waters and sediments.PCBs concentrations varied from 0.3 to 29.9 ng·L-1 in the groundwater,while from 0.1 to 366.1 ng·g-1 in the underground sediments.Correlations were found in concentrations of PCBs in waters and sediments between the underground river and surface systems which indicate that the surface systems play a major role for the transport of PCBs and contamination in the underground river systems.Karst features are liable for the transport behavior.The underground river waters transport PCBs at mean 3 g·day-1.     

Concentrations of heavy metals in fly ash from CAN coal combustion thermal power plant （Canakkale-Turkey）-II

Coal combustion can mobilize trace elements by introducing them to terrestrial, aquatic and atmospheric environments, and if leached, these elements may cause the contamination of soils, surface waters and groundwater. Therefore, these elements may become a hazard to the environment because of their contribution to the formation of toxic compounds, if the ash is not utilized or disposed of properly. This possible contamination could lead to health, environmental and land-use problems. A fluid coal-t-fred thermal power plant （320 MWel） has been in operation since 2005 in Can （Canakkale-Turkey） and currently produces almost half a million tones of fly ash per year. Fly ash is classified based on the nature of constituents present. Fly ashes of Class C contain less than 70% but greater than 50% of silica, alumina, and iron oxide which are typical for the western part of Turkey. When the ash concentrations of these three constituents exceed 70%, fly is classified as F, which is representative of those, produced from Can. Fly ash is enriched in many trace elements particularly metals in this thermal power plant ash. These metals are part of the pyrite structure in the coal and become concentrated in the fly ash during the combustion process. These elements may be surface adsorbed on the glassy spherical fly ash particles. Elements that are surface adsorbed can be quite mobile.     

Sources and mobility of thallium and indium in Canadian lakes

Chemical and biological reactions occurring in lake sediments (early diagenesis) can influence the vertical distribution of trace metals and compromise the use of sediment profiles as historical records of anthropogenic metal pollution. There is thus a ne…     

Response of sediment characteristics to trophic state change at submerged macrophyte zones in a large shallow Lake Wuliangsuhai, China

Sediment samples at different depths were collected from a large shallow lake named Wuliangsuhai in China, in order to determine the response of sediment characteristics to trophic state change. The lake changed from natural state to eutrophication in the late 1970s, creating a Transitional Sediment Layer （TSL） that can be visually used to separate sediments derived from multi-biology and macrophytes. Sediment characteristics were enumerated as a means of corroborating extant eutrophication data from sediment record. Inferences about the timing and trajectory of eutrophication were made using sediment characteristics-based reconstruction. Water content, electrical conductivity, pH, organic matter, nutrient （total nitrogen and total phosphorus） and metals （As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and V） were measured in about 20 different layers of 63-71 cm deep columns of the sediment.     

Betekhtinite from Mt. Lyell,tasmania

Betekhtinite occurs in specimens of recrystallised galena from the North Lyell orebody. Its chemical composition is Cu 59.0, Pb 17.3, Fe 2.7, S 20.6, total 99.6. The thermal stability of betekhtinite is briefly discussed.

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Zusammenfassung In Proben von rekristallisiertem Bleiglanz des North Lyell Erzkörpers kommt Betechtinit vor. Dessen chemische Zusammensetzung ist Cu 59.0, Pb 17.3, Fe 2.7 und S 20.6; total 99.6. Die thermische Stabilität des Betechtinites wird kurz diskutiert.

     

Quaternary glaciation of Mt. Qomolangma-Xixabangma region

The uplift of the Himalaya and Qinghai-Xizang plateau began at the end of Pliocene to the beginning of Early Pleistocene, changing the atmospheric circulation in Asia, enhancing the South Asian monsoon and enormously effecting the climatic conditions and glacial development.According to the evidence of glacial deposits, geomorphology, paleobiology, paleopedology, etc., at least four glaciations can be recognized. The uplift of the Himalayas was earlier than that of other mountains, so that the glaciation occurred in Early Pleistocene, forming small piedmont glaciers on the N slope, whilst at the same time there were wide short valley glaciers on the S slope. During the Middle Pleistocene, the height of Himalaya was about 4000 m a s l, the monsoon was strong, and much water vapour reached the interior of the plateau, the most favourable period for glacial development. Great piedmont glaciers and small ice caps formed on the mountains N of Himalayas and great valley glaciers occurred on the S slope, but no great ice sheet covered the plateau.During the early Late Pleistocene, the Himalayas had risen to over 5000 m asl, forming a barrier against the incursion of the Indian monsoon, so that the precipitation decreased sharply on the plateau N of Himalayas, thus diminishing the extent of the glaciation. But on the high mountains of the S part of Xizang and on several high mountains of the S slope of the Great Himalaya, the precipitation increased and the extent of glaciation reached a maximum. Since Last Glaciation, the precipitation of the alpine zone has decreased more sharply, the climate has become drier and colder, becoming unfavourable for glacial development.During the Holocene, three stages may be distinguished, i.e. the recession in Early Holocene (10,000-8000 BP); the disappearance of most glaciers in the Hypsithermal period in Middle Holocene, (8000-3000 BP); and the neoglacial fluctuations in Late Holocene (3000 BP up to present). The glaciers of the Neoglaciation advanced several hundred meters or even 3–5 km farther than existing glaciers.     

The petrogenesis of volcanics from Mt. Bulusan and Mt. Mayon in the Bicol arc,the Philippines

Pliocene to recent volcanic rocks from the Bulusan volcanic complex in the southern part of the Bicol arc (Philippines) exhibit a wide compositional range (medium- to high-K basaltic-andesites, andesites and a dacite/rhyolite suite), but are characterised by large ion lithophile element enrichments and HFS element depletions typical of subduction-related rocks. Field, petrographic and geochemical data indicate that the more silicic syn- and post-caldera magmas have been influenced by intracrustal processes such as magma mixing and fractional crystallisation. However, the available data indicate that the Bicol rocks as a group exhibit relatively lower and less variable ⁸⁷Sr/⁸⁶Sr ratios (0.7036–0.7039) compared with many of the other subduction-related volcanics from the Philippine archipelago. The Pb isotope ratios of the Bicol volcanics appear to be unlike those of other Philippine arc segments. They typically plot within and below the data field for the Philippine Sea Basin on ²⁰⁷Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb versus ²⁰⁶Pb/²⁰⁴Pb diagrams, implying a pre-subduction mantle wedge similar to that sampled by the Palau Kyushu Ridge, east of the Philippine Trench. ¹⁴³Nd/¹⁴⁴Nd ratios are moderately variable (0.51285–0.51300). Low silica (<55 wt%) samples that have lower ¹⁴³Nd/¹⁴⁴Nd tend to have high Th/Nd, high Th/Nb, and moderately low Ce/Ce* ratios. Unlike some other arc segments in the Philippines (e.g. the Babuyan-Taiwan segment), there is little evidence for the involvement of subducted terrigenous sediment. Instead, the moderately low ¹⁴³Nd/¹⁴⁴Nd ratios in some of the Bicol volcanics may result from subduction of pelagic sediment (low Ce/Ce*, high Th/Nd, and high Th/Nb) and its incorporation into the mantle wedge via a slab-derived partial melt.     

Present condition of Mt. Elbrus volcano

The Freetown layered complex, located on the western coast of Sierra Leone, is a rift-related tholeiitic intrusion associated with the Jurassic (～193 Ma) opening of the Atlantic Ocean at midlatitude. The complex is ～ 60 km long, 14 km wide, and 7 km thick along a major E-W traverse extending from Waterloo to York. Gravity data and dips of laminations in the layered rocks suggest that the intrusive complex is lopolithic in shape, with some parts presently being submarine.

The exposed rocks consist of a rhythmically layered sequence of troctolite, olivine gabbro, gabbronorite, gabbro, and anorthosite. The complex has been divided into four zones delineated by (1) topographic expression, whereby the base of each zone forms a scarp, and the top forms dip slopes and strike valleys; and (2) cyclical repetition of rock types (Wells, 1962). A new detailed stratigraphic section along the Waterloo-York traverse is presented, in which Zone 3 is subdivided into an upper 2000-m-thick anorthosite-gabbro interval and a lower 1700-m-thick rhythmically layered subzone.

Inverted pigeonite first became a cumulus phase at the bottom of Zone 2, before disappearing near the middle of Zone 3 at the anorthosite-gabbro interval, only to reappear at the top of Zone 4 with cumulus titanomagnetite. Mineral compositions in the complex range from An₇₂ to An₇₂ plagioclase, Fo₅₆ to Fo₇₅ olivine, En_38.5 to En_44.8 augite, and En_54.9 to En_74.6 orthopyroxene. The compositions of plagioclase and olivine in Zone 2 vary irregularly, although the overall trend is toward reverse differentiation. By contrast, Zone 4 is characterized by a rapid decrease in Fo and An from the base of the zone upward, followed by an increase. Cryptic variation also is shown by the Ni content of olivine and Cr content of clinopyroxene.

The overall pattern of cryptic variation in the complex suggests continual leakage of fresh magma into the chamber, followed by oscillatory spikes in the rhythmically layered subzone of Zone 3, where major influxes of new magma occurred. The changes in mineral compositions and modal abundances as a function of stratigraphic height are the result of magma recharge, followed by mixing of new and evolved resident magmas in the Freetown magma chamber. This probably resulted in the expansion of the chamber and crystallization in situ without any discharge. The inferred crystallization sequence for each zone is different, reflecting different magma compositions and changes that occur in the magmas during crystallization. The alternative hypotheses that the Freetown Complex formed from a single parental magma, or that mineral layering was the result of the crystallization sequence Fe-Ti oxides→olivine→pyroxene→plagioclase, are not supported by the evidence.     

蒙贡－台加山的冰川及其变化特征

俄罗斯图瓦共和国境内的蒙贡－台加山是位于亚洲中心的一个独立的冰川作用中心。现代冰川共３６条，总面积２７．８ｋｍ２，主要受西风环流及地方性环流的降水补给，具有亚大陆型冰川的特征。小冰期最盛期以来，冰川面积减少４９．３％。近１５０年来，冰川面积和长度继续减少，末端及雪线高度升高。近３０年来，冰川退缩速度加快，冰川物质平衡有１０年左右的波动变化，目前处于负平衡状态。但１９９２－１９９３年两条山谷冰川突然前进。对比亚洲中部其它山系，发现本区冰川动态变化独特，说明不同地区冰川对于全球性气候的响应过程比较复杂。     

瓦里关山与观风山近地面空气7Be浓度季节性变化对比

7Be广泛应用于大气物质传输、表土季节性迁移和微粒混合作用的示踪。它在不同地域空气中的浓度分布构成了多领域研究的基础。7Be在对流层空气中的浓度随地表海拔高度而增加。基于瓦里关山和观风山的位置差异和海拔高差,对比观测其近地面空气7Be浓度变化不仅有益于区域尺度的大气和地表环境过程的示踪,而且对全球尺度的研究也将具重要意义。2002-10-09～2004-01-21,利用美国环境测量实验室的低水平核素表层大气采样系统在瓦里关山和观风山同步连续进行每周1个大气气溶胶样品的采集工作。7Be的比活度系用多道能谱仪进行γ谱测定,测量误差小于6%。中美两实验室对逐周样品测量结果表明两实验室的数据具有很好的可比性。两个站点7Be浓度逐周变化趋势总体相似,具有2～6周的短周期波动,波峰与波谷具有良好的对应关系,其高值或低值波动延迟或超前的差异与区域尺度的天气过程传播一致。瓦里关山和观风山7Be的年均浓度分别为(14.7±1.5)mBq/m3和(4.1±0.9)mBq/m3,前者约为后者的3.6倍。近地面空气7Be浓度与同期降水量的比较表明,在周时间尺度上,两者呈现出较好的预期负相关变化;而在月平均尺度上,两地7Be浓度变化比较稳定。位于内陆地区的瓦里关山受低海拔气团上升的影响较小,其空气中7Be浓度变化较真实地反映了中纬度、高海拔地区的背景水平。观风山地区虽然受到低纬度海洋性上升气团的影响,但7Be浓度变化仍然显示出低纬度、较高海拔地区的预期水平。     

长白山火山研究进展

长白山火山位于中朝边界,由数以百计的火山锥和广袤的熔岩台地组成,是一个庞大的火山群,总面积达12 000km2;它有天池、望天鹅、炮台山3个喷发中心和以基性玄武岩岩流造盾,中性粗面岩熔岩筑锥,酸性碱流岩质火山碎屑、火山灰等随后空降堆积3个主要火山喷发旋回,构成板内巨型层状复式火山。自中新世以来有10个火山幕,近代历史期间仍有过多次喷发,现为处于休眠状态的活火山;该火山受东北亚板块体系制约,与太平洋板块俯冲和东亚大陆裂谷系密切相关。目前适逢地质构造的活动期和千年大喷发、百年小喷发周期的节点,存在着潜在的再喷发危险。     

A subterminal radial fissure eruption on Mt. Etna

The author describes a subterminal radial fissure eruption of Mt. Etna that took place in February 1964. A sketchmap and a chemical analysis of the lava are given.

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Zusammenfassung Der Verfasser beschreibt den subterminalen Radialspaltenausbruch des Ätnas im Februar 1964 und fügt eine chemische Analyse der geförderten Lava bei.

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Résumé L'auteur décrit une éruption subterminale de l'Etna qui a eu lieu sur une fissure radiale en février 1964. Une carte de la région sommitale de l'Etna et une analyse chimique de la lava sont ajoutées.

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Riassunto L'autore descrive l'eruzione radiale verificatasi al cono terminale dell'Etna nel Febbraio del 1964. Dà inoltre un rilevamento schematico della zona del cratere centrale ed il chimismo della roccia.

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, 1964 .

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Dedicated to Professor Dr. A.Rittmann on the occasion of his 75. birthday

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This study is a part of the researches, carried out with the funds of the National Research Council of the Italy under the direction of Prof. A.Ritmann.