Effects of the addition of complexants and bacteria on the soil-plant transfer at metal contaminated sites

Within a series of pot experiments with substrates sampled at heavily to moderately polluted sites of past metal mining activities, it was tried to influence the soil plant transfer of metals via addition of complexants, soil bacteria and perlite. Lettuce （lactuca sativa） was chosen as a universal accumulator plant. A wide range of concentrations in the samples ensures a rather general approach. The goal was to develop a strategy to enable plant growth at metal contaminated substrates for phytoremediation purposes. One contaminated mine tailing from Shiheung/Korea was treated with EDTA, NTA, citric acid, malic acid, NaCl, citrate＋NaCl, as well as compost, to provoke effects from chemical treatment. This should yield low molecular metal complexes in the soil solution and provide a carbon source to natural soil life. Other samples from Shiheung, from Okdong mine tailings, Okdong farmland, as well as from three contaminated sites from a medieval mine tailing at Oberzeiring/Styria/Austrias were treated with Cd- adapted soil bacteria, perlite, and soil bacteria and perlite, to impose of changes in microbial life directly. Fresh mine tailings are low in microbial life and plant- available nitrogen, whereas in the contaminated Austrian medieval samples, conditions have had time to adapt for more than 600 years. In the test substrates, supply with nutrient nitrogen was low, supply with nutrient phosphorus was low to adequate, and supply with potassium and sulfate was adequate. Effects of various additives on the plant yield mainly depend on the initial nutrient status. After harvest, the soils were parted in root soils and bulk soils to recognize possible differences. The lettuce plants were parted in leaves and roots. The solids were characterized by convential methods and aqua regia digestion, as well as by a Tessier-type sequential leaching procedure. The plant samples were digested with HNO3/HClO4. Basically, sample solutions were simultaneously read for 23 elements in ICP-OES in appropriate dilutions. Various treatments result in concentration shifts in root soil, bulk soil, plant roots and plant leaves. Interpretation is not easy, but physiologically active elements or contaminants are usually more involved.     

Influence of contaminated Vistula River water on the groundwater entering the Zakrzówek limestone quarry, Cracow region, Poland

 Chemical composition of water inflows in the Zakrzówek quarry, developed in fractured and karstified Upper Jurassic limestones, is controlled by infiltration of polluted water from the Vistula River and by infiltrating meteoric water. The river water TDS value is 2.5 g/dm³. The quarry waters have 0.6–2.0 g/dm³ TDS. Highly mineralised waters belong to Cl-Na type. With decreasing TDS the percentage of sulphates, calcium, magnesium and hydrocarbonates increases. This seems to result from various processes including dilution of polluted river water, leaching of aquifer rocks, and ion exchange. The transfer time of river water to the quarry is about 100–120 days. Concentration of contaminants contained in the river water declines during the migration through limestones to the quarry. Received: 7 March 1997 · Accepted: 7 December 1998     

Permeable Reactive Barrier for the treatment of contaminated surface water in Katedan industrial development area, Hyderabad, India

Permeable Reactive Barrier （PRB） is an emplacement of inert material （s） in the subsurface, designed to intercept a contaminated plume, provides a preferential flow path through the reactive media, and transforms the contaminant into environmentally acceptable forms to attain concentration remediation goals at the discharge of the barrier. The phenomena, which help in remediation within PRB, are adsorption/sorption, precipitation, oxidation/reduction and biodegradation. Various materials like zero-valent iron, zero-valent bi-metals, natural zeolites, organic carbon, fly ash, zeolites, limestone, activated alumina, apatites, etc. have been tried by many researchers to remove organic and inorganic contaminants. In USA, Canada, and many European countries commercial full-scale and pilot scale PRBs are successfully working. The design and installation of full scale PRBs needs laboratory treatability and dynamic flow column experiments？ The concept of PRB is being applied to treat contaminated surface water in the Katedan industrial area, Hyderabad, India. National Geophysical Research Institute （NGRI）, Hyderabad, India, conducted systematic studies in collaboration with Norwegian Geotechnical Institute （NGI）, Norway, to develop PRB technique to decontaminate the surface water pollution due to industrial effluent. A site assessment study in the Katedan Industrial Area, were carried out and water, soil and sediment from the lakes of the area were found to be polluted with high concentrations of heavy metals like As, Pb, Cr, Cd, Ni, etc. Adsorption studies at NGRI with synthetic samples and in-situ industrial effluent using different reactive media for removing contaminants like arsenic, chromium, cadmium, copper, nickel, lead and zinc have been carried out and yielded satisfactory results. The performance of zero-valent iron and limestone is encouraging in removing As,     

Microwave remediation of oil contaminated soils

The contamination of soil has been the result of commercial, industrial and military activities. Among the variety of the available technologies of organic contaminated soils, thermal methods ensure the greatest efficiency of the above 99%. Thermal techno…     

Phytoremediation of Nephrolepis auriculata (L.) for arsenic, mercury, lead and cadmium in the multiple contaminated soils

In recent years, the concentrations of heavy metals in Chinese herb of Ligusticum chuanxong Hort are overranging the standard of national port of green herbs in GAP bases of Dujiangyan City, Sichuan Province. The aim of the research is to disclose the rem…     

Phytoremediation of Nephrolepis auriculata （L.） for arsenic, mercury, lead and cadmium in the multiple contaminated softs

In recent years, the concentrations of heavy metals in Chinese herb of Ligusticum chuanxong Hort are overranging the standard of national port of green herbs in GAP bases of Dujiangyan City, Sichuan Province. The aim of the research is to disclose the remediation behavior ofNephrolepis auriculata （L.）, a novel pteridophyta found in our research with abundant arsenic, mercury, lead and cadmium from soils. The concentrations of arsenic, mercury, lead and cadmium in the series samples corresponding to roots, stems, leaves ofNephrolepis auriculata （L.） which had been trained in lab with a series of potted incubation experiments through the orthogonal test, were analyzed. Based on the results, methods of the range analysis and variance analysis were used, and it is demonstrated that （1） Nephrolepis auriculata （L.） has a function to beneficiate heavy metals of arsenic and lead, and can well concentrate cadmium and mercury from soils. The distributive behaviors of arsenic, mercury, lead and cadmium in N. sauriculata （L.） follow the order： roots〉leaves〉corms〉stems, stems〉leaves〉roots〉corms, roots〉stems 〉corms〉leaves, stems〉leaves〉roots〉corms; the correlations of the concentrations for arsenic, lead, cadmium and mercury in different tisses of Nephrolepis auriculata （L.） and soils were carried out. Then, the effects of pH value, contents of EDTA and humic acid in soils to arsenic and mercury accumulated by Nephrolepis auriculata （L.） were further studied.     

Mercury concentrations in a contaminated river system in Kazakhstan and biomonitoring of the local population

The River Nura in central Kazakhstan has been heavily contaminated by mercury （Hg） from an acetaldehyde plant located in the industrial city of Temirtau. The plant released Hg-containing wastewater into the river from the 1950s until the mid 1990s and strongly contaminated the bed sediments up to 25 km downstream. In addition, a local power station released an estimated 6 million tonnes of fly-ash into the water which has adsorbed much of the Hg and has become mixed with the natural sediments. River water,fish and agricultural land in the floodplain are also contaminated by Hg. Humans are exposed to Hg primarily via the consumption of contaminated fish from the river. A survey was undertaken in June/July 2005 to investigate Hg concentrations in river water, drinking water, sediments and fish. To estimate the risk posed to the local population, approximately 300 hair samples were collected from people living in villages near the most contaminated section of the river, at a distance of between 5 and 30 km downstream of the acetaldehyde plant, and their dietary habits were recorded. Mercury concentrations in river water ranged from 2-3 ng/L upstream of the source of the pollution to 348 ng/L downstream of the factory outfall pipe. Some drinking water wells close to the river were contaminated, but deeper wells had Hg concentrations below the detection limit.     

Application of the Sequence Stratigraphy in the Study of Cretaceous-Tertiary of the Tarim Basin, Xinjiang, China

1. IntroductionThe Tarim basin, one of the most developed and important areas of marine Cretaceous-Tertiary in China except for south Tibet, is very rich in oil and gas, such as Kekeya oilfield in southwestern Tarim and Kela2 gas field in northeastern Tarim. Because of the expansion, subduction of the oceanic crust of the Tethys and the collision between the India plate and the Eurasia plate during the Cretaceous-Tertiary, the Tethys transgressed into the Tarim basin from west to east fr…     

A geochemical study of redox behavior of As in a contaminated aquifer from Sonargaon, Central Bangladesh

The Bengal Basin has been exposed to the most serious As problem in the world. Although it has been agreed well among many researchers that the contamination has been induced by natural geochemical process, detailed mechanisms are still under debate. Arsenic is easily soluble into groundwater as pentavalent arsenate and trivalent arsenite. Their adsorption behavior for various solid phases, particularly for Fe oxyhydroxide （FeOOH）, is different. Thus speciation of As in solid phase is essential to examine the process of contamination. However, few studies have been done about As speciation in sediment due to its analytical difficulty. In this study, we applied XANES （X-ray adsorption near the edge structure） spectroscopy to determine oxidation states of As and Fe, and investigate As behavior along change in redox condition. We studied the Sonargaon area located 25 km southeast of Dhaka. Sediment core samples were collected from one site in the area up to the depth of 100 m using penetration-drilling method. The samples were packed into oxygen impermeable film with deoxidizer on site,     

Environmental investigation for causality and remediation of cadmium contaminated soils in Tak Province, Thailand

Highly elevated cadmium concentrations in paddy soil in the Mae Sod District, Tak Province, Thailand, was detected and widely reported in 2003. This emergence provoked public interest and demands for responsibility and remedial actions. As zinc mines and concentrator were located in the upstream area, mining activities were proclaimed a contamination source. Department of Primary Industries and Mines （DPIM）, a governmental organization responsible for mining and mineral processing, was thus challenged to verify the reliability of post monitoring data displaying consistently low heavy metal concentrations in compliance with the standard limits for over 15 years. Detailed survey and deep-going research on the causes, boundary and severity of cadmium contamination as well as the environmental impact alleviation were consequently conducted. Environmental samples were accumulated systematically for 2 years throughout the areas of upstream and downstream mining sites. A total of 259 soil samples from 53 spots at the depths of 0-20, 20-40, 40-60 and 60-200 cm were drilled with hand auger. Samples of water, stream sediment and mine tailing were also collected. Chemical analysis for cadmium （Cd）, zinc （Zn） and lead （Pb） concentrations with AAS and ICP were undertaken. The contaminated area was finally defined to spread over approximately 18 square kilometer mainly of mountainous mineralizing land and colluvium.     

A novel strategy using biodegradable EDDS for the chemically enhanced phytoextraction of soils contaminated with heavy metals

For the sake of cost and potential environmental risk, it is necessary to minimize the amount of chelates used in chemically-enhanced phytoextraction. In the present study, a biodegradable chelating agent, EDDS was added in a hot solution at 90℃ to the soil in which garland chrysanthemum （Chrysanthemum coronarium L.） and beans （Phaseolus vulgaris L., white bean） were growing. The application of hot chelate solutions was much more efficient than the application of normal chelate solutions （25℃） in improving the uptake of heavy metals by plants. When 1 mmol kg1 of EDDS as a hot solution was applied to soil, the concentrations ofCu, Zn and Cd and the total phytoextraction by the shoots of the two plant species exceeded or approximated those in the shoots of plants treated with 5 mmol kg^-1 of normal EDTA solution. The concentrations of metals in the shoots of beans were significantly correlated with the relative electrolyte leakage rate of root cells, indicating that the root damage resulting from the hot solution might play an important role in the process of chelate-enhanced metal uptake. The soil leaching study demonstrated that decreasing the dosage of chelate resulted in decreased concentrations of soluble metals in soils. On the 28th day following the application of chelate, the concentrations of soluble metals in the EDDS treated soil were not significantly different from the concentrations in the control soil to which chelates had not been applied.     

Investigation of contaminated Tisza flood-plain soil after heavy metal pollution

There were two significant waves of pollution on the Tisza River at the beginning of the year 2000. With the second wave, there was settled a huge amount of mud contaminated with heavy metals on floodplains. As a result of inundation of the river there wa…     

Moessbauer and XRD characterization of contaminated sediments by coal mining drainage in Neath Canal, South Wales, UK

Sediment cores were collected from the upstream of the Neath Canal in South Wales and characterized for their mineral compositions and iron speciation in order to understand the influence of sedimentary properties on the contaminants of heavy metals. The sediments in the canal have been polluted by ocherous precipitate with heavy metals such as arsenic since a major mine water discharge in spring 1993. The sediment core was obtained just from the discharge point in the canal and distinguished into three layers in the field regarding to their physical properties including visible color, sediment particle composition and dryness. X-ray diffraction （XRD） and M6ssbauer spectroscopy revealed vertical variations of minerals and iron species in depth of the sediment profile. The upper layer, reddish-brown, is wet muddy precipitant and is very fine in particle size, consisting mainly of iron oxide and hydroxide. Arsenic is rich in this layer; probably the sorption on iron oxide surface is the main mechanism. The middle layer, 22.0-27.0 cm, is soft deposit in a yellow color and contains sheet silicate, calcite and goethite. The lower part below 27.0 cm is gray to dark gray in color and contains quartz, pyrite, coal particles that are much more similar to normal aquatic sediment. The upper two layers in brown and yellow colors as newly precipitated mud from AMD contain high concentrations of As, Ni under oxic conditions. The lower part as the old canal sediments under reducing conditions contains high Cu and Zn. Chromium is enriched in the limited part of the low layer, just beneath the boundary between the middle and low parts of the sedimentary column, where the redox conditions shifted from oxic to anoxic. It is clear that the distribution of these heavy metals is closely associated with the redox condition reflected in the iron speciation. Thus different treatments are necessary for each layer of the sediment since different mineral and geochemical properties of the sediment will give different impacts on the heavy metals.     

Petrology,geochemistry, and geochronology of the Zhonggang ocean island,northern Tibet: implications for the evolution of the Banggongco–Nujiang oceanic arm of the Neo-Tethys

This study presents new data relating to the tectonic evolution of the Zhonggang ocean island, within the Mesozoic Banggongco–Nujiang suture zone of northern Tibet, and discusses the implications of these data for the evolution of this region. Thirteen basalt and ten gabbro samples were collected from a sampling transect through this area; these samples have light rare earth element (LREE)-enriched chondrite-normalized REE patterns, and are enriched in highly incompatible elements, yielding primitive-mantle-normalized trace-element variation patterns that are similar to ocean island basalts (OIB). A gabbro dike intruded into basalt of the Zhonggang ocean island and was overlain by basaltic conglomerate, suggesting that this dike was formed after the basalt, but before the basaltic conglomerate. The gabbro dike yields an LA–ICP–MS zircon U–Pb age of 116.2 ± 4.1 Ma, indicating the timing of formation of the Zhonggang ocean island, and suggesting in turn that the Banggongco–Nujiang Neo-Tethys Ocean remained open at this time. These data, combined with the geological history of the region, indicates that the Banggongco–Nujiang Neo-Tethys Ocean opened between the late Permian and the Early Triassic, expanded rapidly between Late Triassic and Middle Jurassic time, and finally closed between the late Early and early Late Cretaceous.     

Metamorphism of the Basement of the Qilian Fold Belt in the Minhe-Ledu Area, Qinghai Province, NW China

The basement of the central Qilian fold belt exposed along the Minhe-Ledu highway consists of psammitic schists, metabasitic rocks, and crystalline limestone. Migmatitic rocks occur sporadically among psammitic schist and metabasitic rocks. The mineral assemblage of psammitic schist is muscovite + biotite + feldspar + quartz ± tourmaline ± titanite ± sillimanite and that of metabasitic rocks is amphibole + plagioclase + biotite ± apatite ± magnetite ± pyroxene ± garnet ± quartz. The migmatitic rock consists of leucosome and restite of various volume proportions; the former consists of muscovite + alkaline feldspar + quartz ± garnet ± plagioclase while the latter is either fragments of psammitic schist or those of metabasitic rock. The crystalline limestone consists of calcite that has been partly replaced by olivine. The olivine was subsequently altered to serpentine. Weak deformations as indicated by cleavages and fractures were imposed prominently on the psammitic schists, occasionally on me     

Characteristics of the Reservoir of the Rehai Geothermal Field in Tengchong, Yunnan Province, China

The Rehai geothermal field in Tengchong County, Yunnan Province is a significant high-temperaturehydrothermal convective system. The geothermal reservoir is composed of granite. Various geothermometersare used to evaluate the reservoir temperature. The most likely temperature of the reservoir as representedby T_(Na-K-Ca) is about 230℃. The chemical and isotopic compositions of fluids before boiling within the reser-voir are estimated. The mixing and dilution of cold and warm waters are discussed. The Rehai geothermal fieldis a high-temperature (hot) water system with the subsurface boiling zone close to the surface. The reservoirpressure at different depths is calculated. And finally the water-rock equilibration is inferred.     

Tectonostratigraphy of the Mesozoic complexes of the northwestern part of the Koryak Highland,Ust’ Belaya Mountains

New data on the structure, age, and composition of the tectonostratigraphic complexes of the western part of the Koryak Highland are presented. The conclusions on the sedimentation conditions are drawn and primary relations are interpreted for most complexes. New Kimmeridgian–Tithonian and Berriasian assemblages of radiolarians are established. Campanian radiolarians are found for the first time in the region.     

Lithology,Biostratigraphy, and Geochronology of the Late Pleistocene–Holocene Sediments on the Coast of Onega Bay of the White Sea

Doklady Earth Sciences - This paper reports on the lithological, micropaleontological, and chronometric data (radiocarbon dating) for one of the areas of the White Sea coast. The sedimentary...