Identification of Metals Contamination in Firing-Range Soil Using Geochemical Correlation Evaluation

Lead, antimony, copper, and zinc are expected contaminants in firing-range soil due to their presence in bullets, shells, etc. These elements are also naturally occurring, so it is important to distinguish between naturally high background concentrations and actual contamination during site investigations. A data visualization technique based on geochemical principles has been successfully applied during range investigations to identify contaminated samples and confirm the success of remediation efforts. For example, at some locations, lead has a natural affinity to adsorb on manganese oxides, yielding positive correlations between lead and manganese concentrations and consistent Pb/Mn ratios in uncontaminated samples. Contaminated samples are identified by anomalously high Pb/Mn ratios. Plots of copper or zinc versus lead provide supporting evidence for a contaminant source; Cu/Pb or Zn/Pb ratios in oxic soils are distinctly different in uncontaminated samples versus samples co-contaminated with these metals. Two case studies are presented from facilities in the United States.     

Transfection of siRNA into <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> (Rotifera)

Lake Taihu is one of the most contaminated lakes in China. Surface sediment data show that the northern area of the Lake has the worst heavy metals pollution, and high heavy metal concentrations were attributed to discharge of untreated and partially treated industrial waste water from cities to the north of the lake. To study geochemical features and pollution history of heavy metals, total content and chemical fractionations of Cu, Fe, Mn, Ni, Pb, and Zn were analyzed for core sediments from western Lake Taihu using the speciation extraction procedure, proposed by the Commission of the European Communities Bureau of Reference (BCR), together with grain size and organic carbon measurements. Results show that sediments are composed of organic-poor clayey-fine silts for Cores MS and DLS, and have similar geochemical features shown by heavy metals. Cu, Fe, Ni, and Zn mainly are associated with the residue fraction, Mn is concentrated in the exchangeable-carbonate and residue fractions, and Pb is concentrated in the Fe–Mn oxide fraction and organic-sulfide fraction. The fractions of Ni, Pb, and Zn bound to Fe–Mn oxide show significant correlations with Mn from the Fe–Mn oxide fraction, and the organic-sulfide fractions of Cu, Mn, Ni, Pb, and Zn are correlated with TOC. The increase of Cu, Mn, Ni, Pb and Zn content and percentage of extractable fractions in the upper layers of the sediments are correlated with anthropogenic input of heavy metals due to rapid industrial development. This coincides with rapid economic development in the Taihu basin since late 1970s. Heavy metals in the surface sediments have certain potential biological toxicity as shown by the higher SEM/AVS ratio.     

Comparative study of the bioaccumulation and elimination of trace metals (Cd,Pb, Zn,Mn and Fe) in the digestive gland,gills and muscle of bivalve Pinna nobilis during a field transplant experiment

The purpose of this study was to investigate the long-term bioaccumulation and elimination of Cd, Pb, Mn, Zn and Fe by Pinna nobilis tissues after their 90 day-transplantation period at Téboulba fishing harbor. During the transplantation period, the Cd, Pb, Mn, Zn and Fe concentrations in the different tissues of the mussels were measured before and after exposure period. Metal (Cd, Pb, Mn, Zn and Fe) accumulation in P. nobilis mussels varied depending on the analyzed tissue and the caging times. Notable differences in Cd, Pb, Mn, Zn and Fe accumulation patterns within the digestive gland, gills and muscle were found and may be due to the ability of each tissue to accumulate metals. During the depuration phase, the elimination of Cd, Pb, Mn, Zn and Fe depended on the target tissue and the metal speciation. Cd, Pb, Mn and Fe were eliminated rapidly from one organ and increased in other when compared to those of 90 day transplanted mussels. The increase of metal loads during the elimination phase is not clear and particularly what kind of processes is responsible for such response. However, it is reasonable to assume that metals increase is related to the existence of an accumulation/detoxification mechanism, which involves the transport of metals from an organ to another. The data obtained indicate that because of the significantly high quantities of Cd, Pb, Mn, Zn and Fe accumulated during the exposure phase, the transplanted mussels are suitable bioindicators for monitoring trace metals in marine ecosystem.     

Leaching Behavior and Risk Assessment of Heavy Metals in a Landfill of Electrolytic Manganese Residue in Western Hunan,China

We analyzed the leaching behavior and chemical speciation of heavy metals in a landfill of electrolytic manganese residue (EMR). The results showed that most of Pb, Cr, As, Cu, and Zn were associated with F4 (residual fraction) and Mn and Co were mainly present in F1 (exchangeable and weak acid soluble fraction). In order to evaluate potential risks of heavy metals to the landfill, modified potential ecological risk index (MPER), potential ecological risk index (PER), index of geo-accumulation (I_geo) assessment, and risk assessment code (RAC) were employed. Ranking order for potential risk based on RAC assessment is Mn > Co > Zn > Cu > Cr = As = Pb. Results from I_geo assessment indicates that Mn poses a potential for high risk to human health and the ecosystem. MPER, which integrates the characteristics of PER and RAC, shows that the potential risks of heavy metals are in the order of As > Cu > Mn > Co > Pb > Cr > Zn. The analysis indicates that Mn, Co, As, and Cu within EMR pose a potential risk when this material is placed in landfills and that these metals should be given particular attention when managing the land disposal of EMR.     

Marine Bacillus spores as catalysts for oxidative precipitation and sorption of metals

The oxidation of soluble manganese(II) to insoluble Mn(III,IV) oxide precipitates plays an important role in the environment. These Mn oxides are known to oxidize numerous organic and inorganic compounds, scavenge a variety of other metals on their highly charged surfaces, and serve as electron acceptors for anaerobic respiration. Although the oxidation of Mn(II) in most environments is believed to be bacterially-mediated, the underlying mechanisms of catalysis are not well understood. In recent years, however, the application of molecular biological approaches has provided new insights into these mechanisms. Genes involved in Mn oxidation were first identified in our model organism, the marine Bacillus sp. strain SG-1, and subsequently have been identified in two other phylogenetically distinct organisms, Leptothrix discophora and Pseudomonas putida. In all three cases, enzymes related to multicopper oxidases appear to be involved, suggesting that copper may play a universal role in Mn(II) oxidation. In addition to catalyzing an environmentally important process, organisms capable of Mn(II) oxidation are potential candidates for the removal, detoxification, and recovery of metals from the environment. The Mn(II)-oxidizing spores of the marine Bacillus sp. strain SG-1 show particular promise, due to their inherent physically tough nature and unique capacity to bind and oxidatively precipitate metals without having to sustain growth.     

铜锈环棱螺对沉积物中重金属的生物积累及其与重金属赋存形态的关系

以铜锈环棱螺（Bellamya aeruginosa）为测试生物,采用28 d沉积物生物积累试验研究铜锈环棱螺对污染河流沉积物中重金属的生物积累,并探讨其与重金属赋存形态的关系.结果表明：铜锈环棱螺肝胰脏对Cd、Pb、Cu、Cr、Zn和Mn均具有较强的积累作用.不同重金属的积累量存在较大差别,Zn的积累量最多,占重金属总积累量的84.32%±4.36%,其次为Cu,占7.67%±2.84%;Pb、Cr和Mn的比例相对较少,分别为3.62%±1.84%、2.22%±1.03%和1.33%±0.15%;Cd所占比例最少,为0.83%±0.53%.肝胰脏中重金属元素之间的相关性均不显著.肝胰脏金属污染指数与沉积物污染综合指数具有显著的正相关关系,铜锈环棱螺可以作为沉积物重金属污染的监测生物.不同沉积物Cd、Cr、Zn和Mn的生物-沉积物积累因子（BSAF）具有较大的差异,Cu和Pb的BSAF比较稳定.Cd的生物积累与沉积物中Cd的可交换的与酸可溶态及可氧化态显著相关;Pb的生物积累与Pb的可还原态显著相关;Cu的生物积累与Cu的可氧化态显著相关;Mn的生物积累与Mn的可交换的与酸可溶态和可还原态显著相关;Cr和Mn的生物积累与其不同形态和总量均不相关.BSAF不宜作为衡量铜锈环棱螺对沉积物中重金属生物积累能力的指标.     

Structural studies on the active site of Escherichia coli RNA polymerase. 1. Interaction of metals on the i and i + 1 sites

The two substrates between which an internucleotide bond is formed in RNA synthesis occupy two subsites, i and i + 1, on the active site of Escherichia coli RNA polymerase, and each subsite is associated with a metal ion. These ions are therefore useful as probes of substrate interaction during RNA synthesis. We have studied interactions between the metals by EPR spectroscopy. The Zn(II) in the i site and the Mg(II) in the i + 1 site were substituted separately or jointly by Mn(II). The proximity of the metals was established by EPR monitoring of the titration at 5.5 K of the enzyme containing Mn(II) in i with Mn(II) going into the i + 1 site, and the 1:1 ratio of the metals in the two sites was confirmed in this way. The distance between the two metals was determined by EPR titration at room temperature of both the enzyme containing Zn(II) in i and Mn(II) in i with Mn(II) going into the i + 1 site, making use of the fact that EPR spectra are affected by dipolar interactions between the metals. The distances calculated in the presence of enzyme alone, in the presence of enzyme and two ATP substrates, and when poly(dAdT).poly(dAdT) was added to the latter system ranged from 5.2 to 6.7 A.     

攀钢冶炼渣堆土壤与优势植物的重金属含量

采用原子吸收分光光度法测定攀钢西渣场冶炼渣堆土壤和6科12种优势植物中Mn、Pb、 Ni、 Cu、Cd等5种重金属含量,并计算优势植物对重金属的富积系数和转移系数.结果表明:渣堆土壤中重金属含量Mn最高(3869.14 mg/kg),次后顺序为Pb>Ni>Cu>Cd;植物与土壤的重金属分布基本一致;所测优势植物中,多数植物对重金属的富积系数较低,而转移系数却较高,如天名精对Cu的转移系数为5.1,羽芒菊对Pb转移系数为3.3,五月艾对Cd的转移系数为6.0,其中8种植物(天名精、羽芒菊等)对Mn的转移系数均大于1.该结果为重金属污染土壤的植物修复提供了参考物种,同时也为植物重金属耐受机制的研究提供了筛选对象.     

Contrasting two methods for determining trace metal partitioning in oxidized lake sediments

A simultaneous (SIM) sediment extraction procedure for low carbonate sediments, which partitions sediment-bound trace metals (Fe, Mn, Zn, Cu, and Cd) into easily reducible (associated with Mn oxides), reducible (associated with Fe oxides) and alkaline extracted (bound to organic) metal is presented. The SIM method was compared to the sequential (SEQ) extraction procedure of Tessier et al. (1979). Both methods showed good agreement for the partitioning of Zn and Cd among the easily reducible, reducible and organic components of sediment. Both methods also showed the same general distribution of Mn, Fe and Cu among the three sediment components, however concentrations of metals recovered by the two methods differed; less Mn and Fe and more Cu was recovered from sediments by the SEQ vs. the SIM procedure. Less recovery of Mn is in part attributed to the loss of this metal in the `in between' reagent rinses required in the SEQ procedure. Greater recovery of Cu by the SEQ vs. the SIM method may be due to the pretreatment of sediment with strong reducing agents prior to the step used for liberating organically bound metals. Advantages of a SIM over the SEQ include rapid sample processing time (i.e. the treatment of 40 samples per day vs. 40 samples in three days), plus minimal sample manipulation. Hence, for partitioning metals into easily reducible, reducible and organic sediment components in sediments low in carbonate, we recommend the use of a SIM extraction over that of a SEQ procedure.     

Influence of selenium on toxicity of some heavy metals in the green algaScenedesmus obliquus

The green alga Scenedesmus obliquus was incubated with heavy metals (Cd2+, Zn2+, Mn2+, Ni2+) with and without selenium. S. obliquus exhibited higher rates of growth and some metabolic activities in cultures containing 0.1 mmol/L Se than those only containing the heavy metals. The positive effect of Se was found with all metals but was negligible with Mn2+.     

Chemotactic responses to metals and anaerobic electron acceptors in Shewanella oneidensis MR-1

Although a previous study indicated that the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 lacks chemotactic responses to metals that can be used as anaerobic electron acceptors, new results show that this bacterium responds to both Mn(III) and Fe(III). Cells were also shown to respond to another unusual electron acceptor, the humic acid analog anthraquinone-2,6-disulfonate. These results indicate that S. oneidensis is capable of moving towards a number of unusual anaerobic electron acceptors, including some that would normally be insoluble in the environment. Additionally, S. oneidensis was shown to migrate in gradients of several divalent cations under anaerobic conditions. Although responses to the reduced forms of redox-active metals, such as Mn(II) and Fe(II), might indicate that S. oneidensis uses gradients of these metals to locate the insoluble electron acceptors Mn(III/IV) and Fe(III) for dissimilatory purposes, responses to non-redox-active metals, such as Zn(II), suggest that movement towards divalent cations might serve other, potentially assimilatory, purposes.     

Molecular operation of metals into the function and state of photosystem II

Action sites of different metals in the electron transport reactions of Photosystem II (PS II) evaluated by delayed fluorescence in the ms range (ms DF) and pigment-pigment, pigment-protein and protein-protein interaction states by electrophoretic measurements are presented. The main targets for the metals action were shown to be:(i) Cd(2+), Ni(2+), Co(2+)-Y(z) or CaMn(4)-cluster on the donor site with dependence on pH;(ii) Ni(2+), Co(2+), Zn(2+), Al(3+), Mn(2+) between Q(A) and Q(B) on the acceptor site; effect of Al(3+) and Mn(2+) is observed only in acidic pH. Investigated metals bring about monomerization of oligomeric and dimeric chlorophyll-protein complexes (CPC) and destabilization of protein-protein interactions. Molecular mechanisms of metals interference with the structure of PS II are discussed.     

Overexpression of METAL TOLERANCE PROTEIN8 reveals new aspects of metal transport in Arabidopsis thaliana seeds

• METAL TOLERANCE PROTEIN8 (MTP8) of Arabidopsis thaliana is a member of the CATION DIFFUSION FACILITATOR (CDF) family of proteins that transports primarily manganese (Mn), but also iron (Fe). MTP8 mediates Mn allocation to specific cell types in the developing embryo, and Fe re-allocation as well as Mn tolerance during imbibition. We analysed if an overexpression of MTP8 driven by the CaMV 35S promoter has an effect on Mn tolerance during imbibition and on Mn and Fe storage in seeds, which would render it a biofortification target.
• Fe, Mn and Zn concentrations in MTP8-overexpressing lines in wild type and vit1-1 backgrounds were analysed by ICP-MS. Distribution of metals in intact seeds was determined by synchrotron µXRF tomography.
• MTP8 overexpression led to a strongly increased Mn tolerance of seeds during imbibition, supporting its effectiveness in loading excess Mn into the vacuole. In mature seeds, MTP8 overexpression did not cause a consistent increase in Mn and Fe accumulation, and it did not change the allocation pattern of these metals. Zn concentrations were consistently increased in bulk samples.
• The results demonstrate that Mn and Fe allocation is not determined primarily by the MTP8 expression pattern, suggesting either a cell type-specific provision of metals for vacuolar sequestration by upstream transport processes, or the determination of MTP8 activity by post-translational regulation.

     

Lead, chromium and manganese removal by in vitro root cultures of two aquatic macrophytes species: Typha latifolia L. and Scirpus americanus pers

The ability of in vitro roots cultures of Typha latifolia and Scirpus americanus to remove metals was studied. Roots were cultivated on Murashige-Skoog medium with 15 microg L(-1) Cr 11, 60 microg L(-1) Pb II or 1.8 mg L(-1) Mn II. Adsorbed metal to root surface was removed by washing with 0.042% HNO3. T. latifolia roots were able to uptake 68.8 microg Pb g(-1), 22.1 microg Cr g(-1) and 1680 microg Mn g(-1), while the S. americanus roots removed 148.3 microg Pb g(-1), 40.7 microg Cr g(-1) and 4037 microg Mn g(-1). About 80-90% of Pb and Cr were absorbed in both cultures. On the contrary, the Mn removal was due mainly to an adsorption process (82-86%). In comparison to the T. latifolia cultures, S. americanus cultures were twofold more efficient to remove Pb and Cr, and threefold more efficient to remove Mn. Both plant species capture metals in the following order: Cr >Pb >Mn. This investigation confirms that in vitro roots cultures could be an alternative as a phytoremediation approach for contaminated water with heavy metals.     

Production of Nicotinamide Adenine Dinucleotide Glycohydrolases by Bacteria

The distribution of heavy metals (Fe, Mn, Zn, Cu, Pb, Ni and Cd) were investigated in various organs and tissues of striped dolphin, Stenella coeruleoalba. The animals were caught alive at Taiji, on the coast of Kii Peninsula, during the open season in December 1978. Determination of the metals was made by atomic absorption spectrophotometry and significant differences of metal concentration in the positions of the muscle, blubber and skin, respectively, were observed. The front ventral muscle of matured dolphins showed the highest concentrations of Zn and Cd and lowest Fe when compared to other parts of the muscle. Most of the metals recorded relatively low concentrations in melon rather than in the other lipid layers of blubber. In skin tissue, the concentrations of Fe, Mn and Zn were significantly higher in black-colored skin than in white skin. Moreover, a difference in the concentrations of metals according to bone position was observed. In general, high concentrations of most of the metals were found in liver, kidney and bone, with low concentrations in brain and the lipid layer of blubber. Furthermore, relatively high concentrations of Cu, Mn and Zn were found in skin, and for Mn, Zn, Ni and Cd it was likewise in pancreas and the reproductive organs. Based upon these results, the nature of the organ(s) of a dolphin that has to be selected for ecological and hygienic comparison was discussed.     

Chronic exposure to elevated levels of manganese and nickel is not harmful to a cosmopolitan detritivore, Megaselia scalaris (Diptera: Phoridae)

Environmental contamination with metals such as manganese (Mn) and nickel (Ni) often results in elevated concentrations of these metals in plant tissues. At high concentrations, these metals are known to have detrimental effects on certain insect herbivores. Using laboratory bioassays and artificial diet, we investigated the development and survival of a cosmopolitan insect detritivore, Megaselia scalaris (Diptera: Phoridae), exposed to concentrations of Mn and Ni reaching 2600 mg Mn/kg and 5200 mg Ni/kg dry mass (dm) in artificial diet. Surprisingly, Ni and Mn at the concentrations tested did not harm this fly. Treatment groups from diets with 260–2600 mg Mn/kg dm and 1300–5200 mg Ni/kg dm had significantly shorter larval development times, overall times to adult emergence, and both pupariation and pupal eclosion times compared to a control group. Wing length of females, a correlate of adult fitness, was also greater in metal treatment groups. Other measures including rate of egg hatch, percentage of emerging flies that were female, and wing length of male flies, were not significantly different in metal treatment groups. We conclude that Megaselia scalaris is tolerant of exceptionally high levels of Mn and Ni.     

Phytoremediation of Cd, Cr, Cu, Mn, Fe, Ni, Pb and Zn from aqueous solution using Phragmites cummunis, Typha angustifolia and Cyperus esculentus

A comparative bioaccumulation pattern and ultra structural changes were studied in Phragmites cummunis, Typha angustifolia and Cyperus esculentus in mixed metals solution of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). P. cummunis was observed to be a shoot accumulator for Cr, Fe, Mn, Ni, Pb, and Zn. However, T. angustifolia was found to be a root accumulator for Cd, Cr, Cu, Fe, Ni and Pb. In addition, C. esculentus also accumulated most of the tested heavy metals in the roots, while Mn and Fe were translocated up to leaves. Further, the long term metal treatment showed maximum accumulation of all heavy metals in P. cummunis followed by T. angustifolia and C. esculentus. Among heavy metals, Fe was accumulated maximum, i.e., >1000 microg g(-1) by all three plants. Simultaneously, the adverse effects on biochemical parameters were noted earlier in C. esculentus than T. angustifolia and P. cummunis. Ultra structural observation showed the cellular changes in wetland plants after longer exposure. Results revealed that P. cummunis and T. angustifolia had more potential for tested metals than C. esculentus. This study established that these wetland plants could be used for heavy metals phytoremediation from metal containing industrial wastewater.     

The effects of eight trace metals in acid soft water on survival, mineral uptake and skeletal calcium deposition in yolk-sac fry of brown trout, Salmo trutta L.

Recently hatched fry of brown trout were exposed to each of eight trace metals (Al, Cd, Cu, Fe, Mn, Ni, Pb, Zn) and to a mixture of all eight, at concentrations typical of soft acid waters, in flowing artificial soft water medium at pH 4·5 and 6·5, for 30 days. At pH 4·5, in the absence of trace metals, net uptake of Ca, Na and K and skeletal calcification were impaired but mortalities were low (10%). At pH 4·5, in the presence of Al, Cu, Pb and Zn individually and the mixture, mortalities were high (87–100%). Cd, Fe, Mn and Ni at pH 4·5 each caused some mortalities (17–43%) and impaired skeletal calcification. At pH 6·5, each of Al, Cd, Cu, Fe, Mn, Pb and the mixture of metals impaired net Ca uptake and (except Al, Fe and Pb) skeletal calcification. Net K uptake was impaired by Al and by the mixture, and less severely by Cu and by Fe. Net Na uptake was impaired by Al and by the mixture, and less severely by Fe and by Mn. The role of trace metals other than Al in fisheries'decline in soft acid waters is discussed.     

OsYSL6 is involved in the detoxification of excess manganese in rice

Yellow Stripe-Like (YSL) proteins belong to the oligopeptide transporter family and have been implicated in metal transport and homeostasis in different plant species. Here, we functionally characterized a rice (Oryza sativa) YSL member, OsYSL6. Knockout of OsYSL6 resulted in decreased growth of both roots and shoots only in the high-manganese (Mn) condition. There was no difference in the concentration of total Mn and other essential metals between the wild-type rice and the knockout line, but the knockout line showed a higher Mn concentration in the leaf apoplastic solution and a lower Mn concentration in the symplastic solution than wild-type rice. OsYSL6 was constitutively expressed in both the shoots and roots, and the expression level was not affected by either deficiency or toxicity of various metals. Furthermore, the expression level increased with leaf age. Analysis with OsYSL6 promoter-green fluorescent protein transgenic rice revealed that OsYSL6 was expressed in all cells of both the roots and shoots. Heterogolous expression of OsYSL6 in yeast showed transport activity for the Mn-nicotianamine complex but not for the Mn-mugineic acid complex. Taken together, our results suggest that OsYSL6 is a Mn-nicotianamine transporter that is required for the detoxification of excess Mn in rice.     

刺楸年轮中重金属含量动态变化及富集特性

为探索刺楸对受污染土壤重金属的富集和修复效应, 以南京栖霞山的乡土树种刺楸及其根际周边土壤为研究对象, 截取其根基部年轮盘及根际土壤样本, 采用ICP-AES法测定年轮及土壤样本中重金属(Cu、Cd、Cr、Mn、Ni、Pb、Zn)元素含量。结果表明: 栖霞山样地中的土壤受Mn、Pb和Zn污染最为严重, 存在Cu、Cd、Mn、Pb、Zn元素的高度复合污染, Cd、Cr、Cu、Ni、Zn在土壤和年轮中存在相关性, Mn和Pb则没有表现出明显的相关性; 刺楸修复受Cd、Mn、Pb、Zn污染的土壤效果并不显著, 更适用于Cr、Cu、Ni污染的土壤修复; 鉴于Cu元素含量变化特征, 刺楸也可以作为反映当地污染历史的记录载体; 刺楸年轮中的重金属元素之间存在交互作用, 其中Cd与Zn元素含量高度相关(r=0.984, p<0.01), 在刺楸年轮吸收重金属元素的过程中, Cu与Cd、Cr、Mn、Zn元素具有协同作用, Mn元素对其他元素有一定的拮抗作用。