Effect of aluminum and chromium on the growth and germination of mesquite (Prosopis juliflora swartz.) DC.

Prosopis seeds were grown under controlled environment in solution of aluminum and chromium at different concentration alone as well as combined together. The effect of these metals was studied on seed germination, root length, shoot length, seedling length and dry biomass. Aluminum and chromium alone, and combined together showed no effects on germination and dry biomass. Chromium alone was found toxic to root, shoot and seedling length. However, application of different concentrations of aluminum increased the root, shoot and seedling growth. It may be concluded that aluminum is not as toxic as chromium, and their combined treatment showed the intermediate effect by ameliorating the impact of one another.     

Phytotoxic effect of aluminum and chromium on the germination and early growth of wheat (Triticum aestivum) varieties Anmol and Kiran

A greenhouse experiment was conducted to determine the phytotoxic effect of aluminum and chromium on the germination and early growth of two wheat (Triticum aestivum) varieties Anmol and Kiran. Seed were treated with 40, 80, 120 and 160 ppm of aluminum and chromium solution individually and in combined form. Observations were made on seed germination, root, shoot and seedling length, and dry biomass. Seed germination and dry biomass showed no effect of aluminum, chromium and combined treatment. Root, shoot and seedling length of both the varieties showed significant (P<0.05) decrease as compared to control. The growth was also reduced as the concentration of aluminum and chromium increased. Seedling length decreased in both the varieties at all the concentration of different treatment of aluminum, chromium and combined treatment. Attempts are being made in different laboratories to construct novel plants using genetic manipulation technologies that may have a greater tolerance to the presence of toxic metals. The results of the present study may help in understanding the mechanisms involved and their possible use in pytoremediation.     

Effects of chromium on seed germination, root elongation and coleoptile growth in six pulses

The ecotoxicological effects of Cr²⁺ on germination and early seedling growth of six pulses were investigated. Seeds of these plants were exposed to seven different concentrations of Cr (0–3.2 mM). The results indicated that root elongation and coleoptile growth of six pulse plants were more sensitive than seed germination for measurement of the toxic of Cr²⁺ pollutions. Different species show different levels of tolerance to Cr²⁺ pollution. Lablab purpureus and Glycine max are the most sensitive to Cr²⁺, their germination percentage, root and coleoptile length were significantly lower than other tested species, by contrast, Lathyrus odoratus and Dumasia villosa are the most resist species, their germination and seedling growth almost were not influenced by Cr²⁺ pollution significantly comparing the control. There were significantly negatively correlations between seedling growth and increasing concentration of Cr²⁺ for Glycine max, Vigna radiate and Lablab purpureus. The significantly negative correlations between germination and increasing concentration of Cr²⁺ were shown for Glycine max, Vigna radiate and V angularis.     

Effect of hydrolysed aluminum(III) and chromium(III) cations on the lipophilicity of talc

Liquid-liquid extraction and electrokinetic studies show that both the talc particles and the isooctane droplets are affected by the presence of hydrolysable metal species of Al(III) and Cr(III). The inherent lipophilicity of talc is unchanged by the hydroxo complexes of these metal species, while positive shifts in zeta potentials of talc and isooctane take place due partly to the strong adsorption of these hydroxo complexes. In the pH range where the hydroxide precipitates, the talc particles are rendered hydrophillic between the precipitation pH and the point-of-zero charge of the metal hydroxide. This hydrophile-lipophile transition of talc in the isooctane-water system relates to heterocoagulation among talc particles, isooctane droplets and hydroxide precipitates.     

Effect of irrigation water qualities on Leucaena leucocephala germination and early growth stage

The evaluation of nonconventional water resources on seed germination and seedling growth performance at early growth stages is still in progress, especially on multipurpose forest trees. This study was designed to test the effect of four water qualities [treated wastewater, industrial, gray and distilled water (control)] on germination and early seedling vigor of Leucaena leucocephala. The results showed that germination was not significantly affected by different water qualities. Seed germination reached a maximum after 17, 14, 14 and 21?days under gray, industrial, treated wastewater and control irrigation, respectively. The highest mean of shoot length was scored under gray water irrigation. Likewise, the highest mean of root length was scored under control, which was not significant from gray water. The means of shoot fresh and dry weight were the highest under treated wastewater. The means of root fresh weight and root dry weight were not significantly different under water treatments. The shoot/root ratios under all water qualities treatments were significantly higher than the control. Growth performance was in progress with no mortality during 21?days of growth. The best nonconventional water quality alternatives based on cleanness, nutrients and toxicity are the gray, treated wastewater and industrial water, respectively.     

Antioxidants and chromium reductases by <Emphasis Type="Italic">Penibacillus</Emphasis> species enhance the growth of soybean under chromium stress

Hexavalent chromium [Cr(VI)] is used in various industries, but its improper and uncontrolled discharge contaminates the environment. In order to circumvent chromium toxicity, several physicochemical and biological strategies have been employed. Among biological approach, microbes convert toxic Cr(VI) to less soluble Cr(III) form and hence can be used to detoxify/remove Cr(VI) from contaminated environment. Considering these, present study was designed to assess the effect of chromium reductases and antioxidants secreted by Penibacillus species to detoxify Cr(VI) and concurrently to augment soybean growth. Bacterial strains (MAI1 and MAI2) were identified as Penibacillus sp. using 16S rRNA gene. Penibacillus species reduced Cr(VI) significantly at pH 7. Maximum Cr(VI) was reduced at 50 and 100 µg/ml of Cr(VI) concentrations. Penibacillus sp. also reduced Cr(VI) significantly at 25 and 35 °C as well as 1 g sodium alginate in 1 g polyvinyl alcohol. Bacterial strains reduced Cr(VI) into Cr(III) which were detected as 33 ± 1 and 35 ± 1 µg/ml in supernatant and 67 ± 2.5 and 65 ± 1 µg/ml in cell debris, respectively, after 120 h. Chromium reductase found in cell-free extract reduced almost all Cr(VI) compared to those observed in cell debris. Both malondialdehyde and antioxidant levels were increased with gradual increase in Cr(VI) concentration. Penibacillus species inoculated soybean plants had better growth and photosynthetic pigments under Cr(VI) stress.     

Origin and geochemical evolution of groundwaters from Lastochka spa （Primorye, Russia）

Obtained new data on major element contents, trace and REE concentrations of sedimentary bedrock and groundwaters in Lastochka spa, along with isotope data, allow solving the problem of origin and evolution of these groundwaters. In the Lastochka area, located in Primorye region （Far East of Russia）, two types of groundwater are found： groundwater （TDS 0.2-0.4 g/L, pH 7.3-7.5） with lower pCO2 levels and groundwater with higher dissolved mineral content （TDS 3.7-4.7 g/L, pH 5.8-6.4） and high pCO2 levels. Our studies proved that both types of groundwaters originated from meteoric water and water-sedimentary stratum interaction has played a main role in forming chemical composition of waters. The main gas composition in the high pCO2 groundwater is CO2, which may as high as 98% of the total amount of all gas. The pressure of CO2, calculated using the water analysis data is at about 0.6 bar, while one measured in the field could reach 2.6 bar. The pressure of CO2 in groundwater with low TDS is 10.2 bar. Our δ^13C data [δ^13C （gas）=-6.22 versus PDB] indicate that most of the ^13C in the free CO2 of Lastochka spa is of upper mantle origin. Sedimentary bedrock is mainly sandstone with a good permeability. Dominate minerals are K-feldspar, quartz and plagioclase and secondary minerals are calcite, limonite, cericite and kaolinite. Our results indicate that the role of mantle CO2 gas is crucial for highly mineralized groundwater. This type of groundwater evolved only during water-rock-gas interaction. Extreme dissolution of albite in the presence of CO2 gas leads to the formation of lower pH and drastic accretion TDS and Na content in high pCO2 water. The violent difference in the trace element concentration in waters is caused by more intensive weathering of primary minerals in the presence of CO2 gas.     

Effect of phosphorus on the attenuation of lead and chromium transport in soils

This study analyses the adsorption of Pb(II) and Cr(III) in soils. These metals are commonly found together in nature in urban wastes or industrial spillages, and the theoretical approach of the work was to evaluate the response of the soil to continuous Cr and Pb spillages to soil in terms of several physicochemical parameters. The influence of an anthropogenic input of phosphorus was evaluated. Continuous flow experiments were run in duplicates in acrylic columns (25 cm × 3.2 cm). The influent Cr(III) and Pb(II) solutions of 10 mg l^?1 and 25 mg l^?1 at pH 5 were pumped upward through the bottom of the columns to ensure saturation flow conditions. Also, successive experiments were run with the above concentrations of Cr(III) and Pb(II) and NaH₂PO₄, keeping metal to phosphorus ratio of 1:0, 1:0.1 and 1:1. Modelling parameters included Freundlich and Langmuir equations, together with the Two-site adsorption model using CXTFIT code. Results obtained allowed concluding that Pb(II) adsorption presents a certain degree of irreversibility and the continued spillages over soil increment the fraction which is not easily desorbed. Cr(III) desorption was almost complete, evidencing its high mobility in nature. The presence of an anthropogenic input of phosphorus leads to a marked increase of both Pb(II) and Cr(III) adsorption in soils. Z-potential measurements allow to discard the electrostatic attraction of Cr(III) and Pb(II) with the surface charged soil as the dominant process of metal sorption. Instead, CheaqsPro simulation allows to identify PbH₂PO₄ ⁺, PbHPO₄ (aq) and CrHPO₄ ⁺ as the dominant species which regulate Cr(III) and Pb(II) transport in soils.     

Mineral species control of aluminum solubility in sulfate-rich acidic waters

The identification of the mineral species controlling the solubility of Al in acidic waters rich in sulfate has presented researchers with several challenges. One of the particular challenges is that the mineral species may be amorphous by X-ray diffraction. The difficulty in discerning between adsorbed or structural sulfate is a further complication. Numerous studies have employed theoretical calculations to determine the Al mineral species forming in acid sulfate soil environments. The vast majority of these studies indicate the formation of a mineral species matching the stoichiometry of jurbanite, Al(OH)SO₄·5H₂O. Much debate, however, exists as to the reality of jurbanite forming in natural environments, particularly in view of its apparent rare occurrence. In this work the use of Al, S and O K-edge XANES spectroscopy, in combination with elemental composition analyses of groundwater precipitates and a theoretical analysis of soluble Al concentrations ranging from pH 3.5 to 7, were employed to determine the mineral species controlling the solubility of Al draining from acid sulfate soils into Blacks Drain in north-eastern New South Wales, Australia. The results indicate that a mixture of amorphous Al hydroxide (Al(OH)₃) and basaluminite (Al₄(SO₄)(OH)₁₀·5H₂O) was forming. The use of XANES spectroscopy is particularly useful as it provides insight into the nature of the bond between sulfate and Al, and confirms the presence of basaluminite. This counters the possibility that an Al hydroxide species, with appreciable amounts of adsorbed sulfate, is forming within these groundwaters.Below approximately pH 4.5, prior to precipitation of this amorphous Al(OH)₃/basaluminite mixture, our studies indicate that the Al³⁺ activity of these acidic sulfate-rich waters is limited by the availability of dissolved Al from exchangeable and amorphous/poorly crystalline mineral species within adjacent soils. Further evidence suggests the Al³⁺ activity below pH 4.5 is then further controlled by dilution with either rainwater or pH 6-8 buffered estuarine water, and not a notional Al(OH)SO₄ mineral species.     

Effect of incorporation of iron and aluminum on the thermoelastic properties of magnesium silicate perovskite

In situ X-ray diffraction measurements of Fe- and Al-bearing MgSiO₃-rich perovskite (FeAl-Pv), which was synthesized from a natural orthopyroxene, were performed at pressures of 19–32 GPa and temperatures of 300–1,500 K using a combination of a Kawai-type apparatus with eight sintered-diamond anvils and synchrotron radiation. Two runs were performed using a high-pressure cell with two sample chambers, and both MgSiO₃ perovskite (Mg-Pv) and FeAl-Pv were synthesized simultaneously in the same cell. Thus we were able to measure specific volumes (V/V ₀) of Mg-Pv and FeAl-Pv at the same P−T conditions. At all the measurement conditions, values of the specific volume of FeAl-Pv are consistent with those of Mg-Pv within 2 Standard Deviation, strongly suggesting that effect of incorporation of iron and aluminum on the thermoelastic properties of magnesium silicate perovskite is undetectable in this composition, pressure, and temperature range. Two additional runs were performed using a high-pressure cell that has one sample chamber and unit-cell volumes of FeAl-Pv were measured at pressures and temperatures up to 32 GPa and 1,500 K, respectively. All the unit-cell volume data of FeAl-Pv perovskite were fitted to the high temperature Birch–Murnaghan equation of state and a complete set of thermoelastic parameters of this perovskite was determined with an assumption of K′ _300,0 = 4. The determined parameters are K _300,0 = 243(3) GPa, (∂K _T,0/∂T) _P = −0.030(8) GPa/K, a ₀ = 2.78(18) × 10⁻⁵ K⁻¹, and b ₀ = 0.88(28) × 10⁻⁸ K⁻², where a ₀ and b ₀ are the coefficients of the following expression describing the zero-pressure thermal expansion: α _T,0 = a ₀ + b ₀ T. The equation-of-state parameters of FeAl-Pv are in good agreement with those of MgSiO₃ perovskite at the conditions corresponding to the uppermost part of the lower mantle.     

Effect of chromium on phase relations in the join forsterite-anorthite-diopside in air at 1 Atm

The effect of Cr on the silicate system has been studied in air at 1 atm by adding a small amount of MgCr₂O₄ (0.2–0.5 wt.%) to the join Mg₂SiO₄ (forsterite) — CaAl₂Si₂O₈ (anorthite) — CaMgSi₂O₆ (diopside), which has been considered to form a thermal divide in the system CaO-MgO-Al₂O₃-SiO₂. The spinel primary field is enlarged compared with that in the Cr-free join at the expense of the anorthite primary field. The piercing points forsterite+anorthite+diopside+liquid and forsterite+anorthite+spinel+liquid approach each other with increasing MgCr₂O₄, meet at the join with 0.25 wt.% MgCr₂O₄ (0.20 wt.% Cr₂O₃) to form the ‘isobaric quaternary invariant point’ forsterite+anorthite+diopside+spinel+liquid, and then separate again as new ‘piercing points’ of diopside+spinel+anorthite+liquid and forsterite+diopside+ spinel+liquid. This process indicates that the join Mg₂SiO₄-CaAl₂Si₂O₈-CaMgSi₂O₆ containing more than 0.2 wt.% Cr₂O₃ cannot be a thermal divide in the basalt tetrahedron. The results of the present study show that the presence of a minor amount of Cr causes a significant effect on the phase relations and therefore, the role of Cr must be taken into account in the formulation of a petrologic model.     

Studies on the chromium concentrations in topsoils and subsoils of two rapidly industrialized cities in the Yangtze River Delta in east China

A total of 782 topsoil samples (0–20 cm) and 371 subsoil samples (20–40 cm) were collected from agricultural land in two rapidly industrialized areas with a large number of small rural industries in southeast China, Zhangjiagang City (ZJG) and Changshu City (CS), to measure soil chromium (Cr) concentrations. Kriging and cokriging were used to predict the spatial distribution of Cr in the topsoils and subsoils. Paired-samples t test and spatial distribution maps were used to compare the Cr concentrations in topsoils and subsoils. The mean Cr concentration in ZJG topsoils was significantly higher than that in ZJG subsoils and the mean Cr concentration in CS topsoils showed no significant difference from that in CS subsoils. The Cr concentrations in topsoils were higher than those in subsoils over most of the area of ZJG and part of CS, suggesting that Cr accumulation had occurred in these areas and extrinsic factors have an important role controlling the distribution of Cr in topsoils. Semivariogram/cross-semivariogram was used to evaluate soil Cr spatial variability. The Cr in ZJG topsoils, ZJG subsoils, and CS topsoils had moderate spatial dependence and the Cr in CS subsoils had strong spatial dependence. Cr in ZJG subsoils had longer effective range than Cr in ZJG topsoils, suggesting that the anthropogenic factors affecting Cr distribution in ZJG topsoils; and Cr in CS topsoils had longer effective range than Cr in CS subsoils, indicating that soil formation may be the major explanation for the decrease in the variation of Cr in topsoils. A significant correlation was found between the Cr in topsoils and Cr in subsoils, indicating that natural factors also play an important role as extrinsic factors that control the distribution of Cr in topsoils.     

Toxic (aluminum, beryllium, boron, chromium and zinc) in groundwater: health risk assessment

The objective of this study is to determine the seasonal water quality variations of the major springs of the Yarmouk Basin (YB) of north Jordan. A total of 36 water samples were collected in October 2006 (dry season) and in May 2007 (wet season) and analyzed for temperature, hydrogen ion concentration, electrical conductivity, aluminum, beryllium, boron, chromium and zinc. The hydrogen ion concentration was found in the alkaline ranges (7.01?C7.87) and (7.01?C8.09) for the pre and post-wet season water samples, respectively. Electrical conductivity varied from 300 to 1199???S/cm and from 424 to 962???S/cm for the dry and wet season water samples, respectively. The results of heavy metals analysis indicated that some water samples exceeded the Jordanian Standards for drinking water. Overall, the results showed that the water springs of the Yarmouk Basin in north Jordan is contaminated with heavy metals that might affect human health as well as the health of the ecosystem.     

Germination and growth of six plant species on contaminated soil with spent oil

Effects of contaminated soil with spent oil on germination, above ground height and biomass of six herbaceous plant species were investigated by conducting a general phytotoxicity test and growth inhibition assessment. Six local plant species were used in order to investigate plant’s ability to germinate and survive in a gradient of contaminated soil with spent oil. The species selected for this experiment include one species of Fabaceae (Medicago truncatular), four species of Gramineae (Bromous mermis, Secal seral, Triticum sativa and A gropyron deserterum) and one species of Linaceae (Linum ussitasimum). Inhibitory effect of contaminated soil on germination, height of young seedling and dry weight were measured. In this study an artificial soil with a light texture included 85% sand, 10% silt and 5% clay was used. The exposure to the contaminated soil carried out using four consecutive concentrations (25, 50, 75, 100 g/kg). Results obtained from the current investigation indicate that all species perform dose-dependent responses to the contaminated soils. Reduction in germination, above ground height and biomass for all species were significantly (P < 0.05) different when compared to their controls, however, Medicago truncatular performed the highest and Linum ussitatisimum the lowest inhibitory effect for germination, above ground height and dry weight of seedling.     

Effects of estuarine organic matter biogeochemistry on the bioaccumulation of PAHs by two epibenthic species

Polycyclic aromatic hydrocarbon (PAH) biota-sediment accumulation factors (BSAF) were quantified in sediments from two sites in southeastern Louisiana in a 14 d microcosm study usingPalaemonetes pugio, andRangia cuneata and two radiolabeled PAHs, phenanthrene and benzo[a]pyrene (b[a]p). For both PAHs studied, mean BSAFs were significantly higher (p<0.0001) in both organisms in sediments from Bayou Trepagnier, (BSAF=0.628 g OC g TLE⁻¹), a brackish swamp, compared to Pass Fourchon (0.065 g OC g TLE⁻¹), a coastal salt marsh. In order to explain observed patterns in BSAFs, organic carbon-normalized PAH distribution coefficients between the sediment and freely dissolved phases (K_OC)_OBS were determined as well as the various geochemical variables of particulate and dissolved organic matter (POM and DOM, respectively). These included analyses of particle surface area, total organic carbon (TOC), carbon to nitrogen ratios (C∶N), and dissolved organic carbon (DOC). Bayou Trepagnier was higher in surface area, TOC, C∶N, as well as DOC suggesting that the difference in BSAFs may be attributed to compositional differences in POM and DOM between sites. We can not exclude the possibility that other factors (such as differences in organism behavior resulting from contrasting sediment characteristics) were responsible for BSAFs varying between the two sites. Phenanthrene BSAFs were typically higher than b[a]p BSAFs, suggesting contaminants were limited in their desorption from sediment particles as a function of PAH molecular weight. Mean BSAFs for both PAHs were higher on Day 7 than on Day 14. The reason for this decrease is unclear, but did not appear to be due to organisms becoming increasingly stressed in the microcosms. Visual observations indicated that animals remained feeding while no decreases in organism total lipid levels were detected. The trends in BSAFs between sites and over the time course of this experiment suggest that contaminant bioaccumulation in estuarine systems should not be considered to be an equilibrium process.     

Estimating species diversity: Comparison of two algorithms

Two approaches to estimating the number of species in a lithologic unit are compared. An empirical model of the sampling process, which involves fitting the equation of a rectangular hyperbola to the data from a collector's curve, is compared with a logarithmic model derived from a statistical theory of sampling. The two approaches give equally accurate estimates of species richness when organisms are randomly dispersed but the logarithmic model generally requires more sampling than the hyperbolic model.     

青藏高原两种草甸类型人工降雨截留特征分析

选取青藏高原典型多年冻土区风火山小流域高寒草甸和沼泽化草甸典型样地进行人工降雨截留试验,综合运用统计分析、模型回归分析等方法,对两种草甸类型截留特征及其影响因子进行分析。结果表明:两种草甸类型对降雨的截留能力是不同的,高寒草甸最大截留量0.61mm,沼泽化草甸为0.18mm;高寒草甸的最大截留率为12.4%,沼泽化草甸为3.8%。通过分析各因子对截留的影响,得出高寒草甸截留量与降雨量呈对数函数关系,沼泽化草甸截留量与降雨量呈二次多项式关系;两种草甸截留量与降雨强度都呈幂函数关系,与植被盖度均呈线性相关关系。     

Effect of manganese tailings on capsicum growth

The impact of Mn in manganese waste rocks and electrolytic manganese residues on the growth of capsicum was studied via pot experiments. The product yield and manganese nutrition were mainly evaluated in this study. The results showed that the ingredients of manganese tailings were beneficial to the increase of chlorophyll contents in the capsicum. The chlorophyll contents were raised by 12.6%–28.7%, 7.18%–12.1% and 9.70%–13.7%, respectively, corresponding to the idiophase of flower bud, the initial florescence and the fruit expansion stage. Moreover, the additive significantly improved capsicum’s economic features, such as its height, stem width, fruit length and weight and the yield of fresh fruit. These parameters were raised by 11.9%–25%, 18.6%–25.6%, 20.7%–35.4%, 10.4%–27.6% and 11.4%–65.7%, respectively. At the meantime, the manganese taken up by stems and leaves of the capsicum also increased by 11.7%–23.4% and 33.9%–62.8%, respectively. The manganese which remained in the soil was less than that in the original soil due to plant absorption and rainfall loss in pot experiments. It is concluded that both manganese residues and the mixture of manganese waste rock and manganese residue could indeed be made full use of as a fertilizer which can provide Mn nutrition.     

典型铬渣污染场地铬污染特征研究

选取西南岩溶区某傍河铬渣堆场为研究对象,对场地不同位置与深度的土壤及地下水样品进行采集,通过数理统计对Cr在场地中的空间分布特征以及场地对地下水的影响进行了分析。结果表明:土壤中总Cr浓度的水平分布具有差异性,表层土壤Cr浓度由上游到下游呈明显降低趋势,变化率为3.59;深层饱水带土壤中总Cr浓度分布受到地下水流场的影响,场地下游土壤铬浓度明显高于上游;杂填土垂向剖面的铬浓度分布不同于坡残积红黏土,杂填土中铬浓度随着深度的增加而增加,浓度与土壤深度的关系可用y=63.88ln（x）-75.221来表示;而在红黏土中剖面中,铬大量聚集在土壤表层,后随着深度的增加铬浓度逐渐降低,接近基岩面有升高趋势;场地地下水中Cr（Ⅵ）的浓度受深层土壤中总Cr浓度的影响,两者呈正相关。      

含缓蚀剂钻井液对铝合金钻杆材料的腐蚀影响

铝合金钻杆在钻井液中发生腐蚀会引发严重的孔内事故。为了延缓钻井液对铝合金钻杆的腐蚀作用,在pH值为10、温度为70 ℃的聚磺体系钻井液中,分别加入一定比例的有机缓蚀剂（十二烷基苯磺酸钠,C18H29NaO3S或SDBS）及稀土缓蚀剂〔硫酸镧,La2(SO4)3〕,通过力学性能测试,研究缓蚀剂对7075系铝合金钻杆材料腐蚀的影响。结果表明：上述2种缓蚀剂均可降低铝合金在碱性钻井液中的腐蚀,提高铝合金钻杆抗拉强度最高达6.73%;合金中Cu、Mg、Si等元素的第二相粒子是腐蚀的敏感区域,第二相粒子脱落后即形成腐蚀坑;在产生腐蚀裂纹时,腐蚀产物主要由Al、C、O等元素组成。