Average Fe Content Research Articles

Variable relationships between the hydrophobic fraction of dissolved organic matter and metals in Scottish freshwater before the estuarine mixing zone

The organic-Fe association in Scottish freshwater rivers has received little attention compared with in the estuarine mixing zone. We collected 201 water samples from rivers and lakes in Scotland across different sampling years and seasons. Relationships among the hydrophobic (HPO) fraction of dissolved organic matter (DOM), specific UV absorbance (SUVA254), and dissolved metals (Al and Fe) were examined to better understand their co-transportation in Scottish waters. The average DOM, HPO fraction, Fe, and Al concentrations for all the samples co-varied and were lower during winter than during summer. There was a strong positive correlation between DOM and HPO fraction concentrations (R2 = 0.99, p < 0.0001). A significant positive correlation was also found between the HPO fraction and Fe and Al concentrations. The regression slope indicating the overall relationships between the HPO fraction and Fe concentrations differed by as much as 12 times depending on both the sampling period and the river. These slope differences were not significantly determined by the chemical structures of DOM, SUVA254, or Al and Cu concentrations. These results suggest that the Fe transport capacities vary among the Scottish rivers because of other factors such as seasonal effects (temperature and the level of water table) and a suspended solid concentration in the water column.

Effects of foliar Fe and Zn fertilizers on storage root Fe, Zn, and beta-carotene content of sweet potato (Ipomoea batatas L.)

Foliar sprays of iron (Fe) and zinc (Zn) fertilizers are effective in improving Fe and Zn concentrations in sweet potato. The objective of this experiment was to examine the effects of foliar fertilization with Fe and Zn in association with amino acids (AA) on Fe and Zn biofortification and the nutritional quality of sweet potato under both greenhouse and field conditions. Compared with treatment CK, foliar Fe, Zn, and Fe-Zn fertilizer applications could biofortify Fe and Zn concentrations and other nutrients in sweet potato to different extents. However, when 0.4% (wt/vol) AA was added to Fe-Zn fertilizer, the average Fe and Zn concentrations were increased by 70.2% and 59.8% under greenhouse conditions, and 52.9% and 43.7% under field conditions, respectively. The Fe-Zn-AA fertilizer application also resulted in incremental increases in root yield and beta-carotene content. This research identified some useful foliar fertilizers for accelerating Fe and Zn accumulation in selected sweet potato cultivars.

Oxidation States of Fe in Constituent Minerals of a Spinel Lherzolite Xenolith from the Tariat Depression, Mongolia: The Significance of Fe3+ in Olivine

The oxidation states of Fe within olivine, orthopyroxene, clinopyroxene, and spinel in a spinel lherzolite xenolith from the Tariat Depression, Mongolia were investigated using 57Fe Mössbauer spectroscopy to evaluate the redox condition of the upper mantle from which the Tariat spinel lherzolite xenolith was derived. The purity of separated minerals for the Mössbauer spectroscopic analysis was examined using X-ray powder diffraction, Raman spectroscopy, and transmission electron microscopy. Average Fo and Fe contents of olivine at the core part of the xenolith are 89.9(4) mol % and 0.195(3) atoms per formula unit, respectively. The Fe3+/ΣFe values of the olivine, orthopyroxene, clinopyroxene, and spinel, determined by Mössbauer spectroscopic analysis, are 0.027(2), 0.15(1), 0.26(3), and 0.34(5), respectively. The Mössbauer spectrum of olivine consists of two doublets assigned to Fe2+ at the octahedral sites and one doublet, with I.S. of 0.40(2) mm/s and Q.S. of 0.69(3) mm/s assigned to Fe3+ at the octahedral site. Since the Tariat spinel lherzolite xenolith in this study shows no evidence of metasomatism or thermal alteration, the existence of a small amount of Fe3+ in olivine and the fairly high Fe3+ contents of clinopyroxene, orthopyroxene, and spinel imply that the upper mantle under the Tariat area was in a rather oxidized condition.

Porosity characteristics of the Eocene mixed-sediment reservoirs in the saline lacustrine basin, Qaidam, China

In recent years, significant progress has been achieved in the field of deep exploration in the Yingxi area of the Qaidam Basin. The Eocene was characterized by mixed sediments in the lacustrine basin. The area consists of lacustrine carbonate, detrital material, and mud. All rocks contain numerous salt minerals. Via core observation, physical property analysis, capillary pressure tests, image logging, and field emission scanning electron microscopy, results reveal that the rocks contain a double porosity system. The first are fractures and salt mineral dissolution pores possessing a large pore radius, and the second are cracks between the salts and dolomite intercrystalline pores with a small pore radius. These two types of pores caused the double-platform feature with a lower narrow portion and upper wide portion on capillary pressure curves. Overall, the physical properties of the rocks are deficient, with low porosity-ultra-low permeability. Moreover, pores and throats are generally acceptable. Mineralogical composition analysis based on electronic probe shows that the rocks possess a high content of both silicon and aluminum, but low content of iron and manganese. The average FeO content in the dolomicrite is 1.322%, and that of MnO is 0.060%, both of which are lower than average Fe or Mn content in hydrothermal dolomite. It is believed that the dolomicrite possesses a penecontemporaneous metasomatic formation mechanism. The dolomitization process produces a large number of shrunken intercrystalline pores. These kinds of matrix pores, functioning as storage space, constitute an important support factor for the sustained and stable production of oil and gas in the study area.

Estimation of the Levels of Fe in Wheat and Maize Flour Milled using Commercial Milling Machine and A Home Blender

Milling devices are among the most commonly used in our indigenous markets and homes and variety of elements such as Cu, Ni, Zn, Pb, Ti, Co, Cr, Al, Si, and Fe are used in their manufacture and fabrication. Often times they are present as alloys. With prolonged processing, these metals are gradually introduced as contaminants in the food being processed. Wheat and maize were selected for this study due to their wide usage as sources of protein and carbohydrate in Nigeria and Africa in general. The samples were cleaned by picking out sand, stones and other impurities and ground using the commercial milling machine and a home blender and were digested with HNO3 and HClO4 in the ratio of 4:1 and analyzed using AAS. Average Fe concentration values for both wheat and maize samples milled with commercial milling machine is 13.53 mg/kg and 26.79 mg/kg respectively while samples milled with the home blender gave concentration values of 4.00 mg/kg and 2.64 mg/kg for wheat and maize respectively. The high concentration of Fe in ground maize and wheat milled using the commercial milling machine could be attributed to the abrasive friction of the grinding disc as the grains come in contact with it during grinding resulting in its chipping off into the milled sample. It is therefore recommended that the commercial milling machine be redesigned with the incorporation of a permanent magnet to minimize or totally eliminate the introduction of Fe fillings into the ground grains and other foodstuffs. Keywords: Commercial milling machine, wheat, maize, contaminants, home blender, grinding

Mineralogical and physical beneficiation studies for iron extraction from Bardaskan titanomagnetite placer deposit

In this work, a bench-scale process was developed using mineral-processing methods to recover iron from a placer deposit located in Bardaskan, Khorasan-e-Razavi, Iran. The mineralogical studies were performed by X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Electron Probe Micro-Analyzer (EPMA), and an optical microscope. These studies indicated that titanomagnetite, magnetite, and hematite were presented in the sample as valuable minerals. In contrast, the gangue minerals were silicates such as pyroxene, plagioclase, quartz, feldspar, calcite, and some secondary minerals. The optimum liberation degree of the iron-containing minerals was obtained to be 75 µm with average Fe and TiO2 contents of 5% and 1%, respectively. The analysis showed that magnetite was the main iron mineral, and most of the hematite was formed due to martitization. Also minor ilmenite contents were found in hematite and magnetite in a blade form. The maximum TiO2 content in the magnetite lattice was 19%, only 8% of which was recovered to the magnetic product. Eventually, an iron concentration flow sheet was developed, which included the removal of a major part of silicates and then iron minerals by a low intensity wet magnetic separator. The final product contained 55, 7.8, and 0.77% of Fe, TiO2, and V2O5, respectively, which can be used for iron production, and V2O5 extraction (as the by-product).

Using ICP and micro-PIXE to investigate possible differences in the mineral composition of genetically modified versus wild-type sorghum grain

In the present study, possible differences in the mineral composition of transgenic versus non-transgenic sorghum grains were investigated using inductively coupled atomic emission spectroscopy (ICP-AES); and, in-tissue elemental mapping by micro Proton-Induced X-ray Emission (micro-PIXE) analysis. ICP AES was used to analyse the bulk mineral content of the wholegrain flour derived from each genotype; whilst micro-PIXE was used to interrogate localised differences in mineral composition specific to certain areas of the grain, such as the bran layer and the central endosperm tissue. According to the results obtained, no significant difference in the average Fe, Zn or Ca content was found to differentiate the transgenic from the wild-type grain using ICP-AES. However, using micro-PIXE, a significant reduction in zinc could be detected in the bran layer of the transgenic grains relative to wild-type. Although it is difficult to draw firm conclusions, as a result of the small sample size used in this study, micro-PIXE has nonetheless proven itself as a useful technique for highlighting the possibility that there may be reduced levels of zinc accumulation in the bran layer of the transgenic grains. Given that the genetic modification targets proteins that are highly concentrated in certain parts of the bran tissue, it seems plausible that the reduced levels of zinc may be an unintended consequence of the silencing of kafirin proteins. Although no immediate health or nutritional concerns emerge from this preliminary finding, it is noted that zinc plays an important biological role within this part of the grain as a structural stabiliser and antioxidant factor. Further study is therefore needed to assess more definitively the extent of the apparent localised reduction in zinc in the transgenic grains and how this may affect other important grain quality characteristics.

Effects of Ni/Fe bimetallic nanoparticles on phytotoxicity and translocation of polybrominated diphenyl ethers in contaminated soil

In vivo studies of the interactions of polybrominated diphenyl ethers (PBDEs) in plants have generally focused on uptake, translocation, metabolism and accumulation, but there were limited reports about the phytotoxicity and translocation of PBDEs in contaminated soil with the effects of nanoparticles. In this study, the effects of Ni/Fe bimetallic nanoparticles on translocation of polybrominated diphenyl ethers (PBDEs) in contaminated soil and its phytotoxicity to Chinese cabbage were investigated by soil culture experiments. The results showed that the plant biomass, germination rate, and shoot and root lengths of treated soil (S-5) increased by 0.0044 g, 15%, and 5 and 6 mm, respectively, compared with untreated soil (S-2B). The average Ni and Fe contents of the edible parts(stem and leaf) of the S-5 sample, which contained 0.03 g/g Ni/Fe and 10 mg/kg BDE209, were measured at 1.71 and 184 mg/kg, respectively. The superoxide dismutase, peroxidase and catalase activities in the S-5 sample decreased by 12%, 6.1% and 5.9%, respectively, while compared with the S-2B sample. In all treatments, the contents of BDE209 and the total PBDEs in sample S-5 were lowest, suggesting that the fresh Ni/Fe nanoparticles had higher toxicity than that of the aged nanoparticles. And the lower brominated PBDEs (tri-to nona-) were detected in samples, indicating uptake, debromination and/or metabolism of PBDEs existed in plants. The phytotoxicity and translocation of BDE209 in the contaminated soil decreased as a result of the effects of the Ni/Fe bimetallic nanoparticles.

Maize inbreds from different heterotic groups as favorable sources for increased potential bioavailability of magnesium, iron, manganese and zinc

Malnutrition, as a global problem, is mainly caused by low level of mineral elements in staple food (deficient soil). Biofortification is based on selection of genotypes with enhanced concentration of mineral elements in grain, as well as decreased concentration of substances which interfere bioavailability of mineral elements in gut (like phytic acid), and increased content of substances that increase availability (such as β-carotene). The experiment with 51 maize (Zea mays L.) inbred lines with different heterotic background was set up in order to evaluate chemical composition of grain and to determine the relations between phytic acid (PA), β-carotene, and mineral elements: Mg, Fe, Mn, and Zn. The highest average phytate, β-carotene, Fe, and Mn content was found in grain of inbreds from Lancaster heterotic group. The highest content of Mg was in grain of Independent source and Zn in grain of BSSS group. Increased level of Fe and Mn in Lancaster lines could be partially affected by higher PA content in grain, while increased β-carotene content could improve Mn and Zn availability from grain of BSSS genotypes and Mg availability from Lancaster inbreds. It is important to underline that PA reduction is followed by Zn content increase in grain of Lancaster heterotic group, as well as that variations in Mg, Fe, and Mn contents are independent on PA status in inbreds from Independent source, indicating that the genotypes with higher Mg, Fe and Mn status from this group could serve as favorable source for improved Mg, Fe, and Mn absorption.

Diversity of Iron and Zinc Content in Bananas from East and Central Africa

Bananas and plantains (Musa sp.) are major staple foods in many developing countries of the world. Although bananas are rich in carbohydrate, fiber, protein, fat, and vitamins A, C, and B6 they are largely deficient of iron (Fe), iodine, and zinc (Zn). A small increase in the micronutrient content of bananas could play a major role in combating disorders that are due to deficiency of mineral micronutrients such as Fe and Zn. The objective of this study was to determine the Fe and Zn content of 47 banana genotypes from a germplasm collection in Uganda using atomic absorption spectrophotometry. The Fe and Zn content showed wide variability and highly significant differences (P &lt; 0.001) within and among the different banana categories selected for this study. The highest average Fe content (1.42 mg/100 g) was found in ‘Saba’ (ABB) while the least Fe content (0.06 mg/100 g) was found in ‘Kikundi’ (AAA). The highest average Zn content (1.21 mg/100 g) among the analyzed accessions was found in ‘Kivuvu’ (ABB) while Zn was not detectable in both ‘Kabucuragye’ (AAA) and ‘Grand Naine’ (AAA). Considering these figures, there is a greater than 20-fold variation in the Fe and Zn levels of the banana genotypes used this study suggesting that genetic improvement of genotypes for enhanced micronutrient levels may be achieved by breeding.

Ferrous iron content of intravenous iron formulations.

The observed biological differences in safety and efficacy of intravenous (IV) iron formulations are attributable to physicochemical differences. In addition to differences in carbohydrate shell, polarographic signatures due to ferric iron [Fe(III)] and ferrous iron [Fe(II)] differ among IV iron formulations. Intravenous iron contains Fe(II) and releases labile iron in the circulation. Fe(II) generates toxic free radicals and reactive oxygen species and binds to bacterial siderophores and other in vivo sequestering agents. To evaluate whether differences in Fe(II) content may account for some observed biological differences between IV iron formulations, samples from multiple lots of various IV iron formulations were dissolved in 12 M concentrated HCl to dissociate and release all iron and then diluted with water to achieve 0.1 M HCl concentration. Fe(II) was then directly measured using ferrozine reagent and ultraviolet spectroscopy at 562 nm. Total iron content was measured by adding an excess of ascorbic acid to reduce Fe(III) to Fe(II), and Fe(II) was then measured by ferrozine assay. The Fe(II) concentration as a proportion of total iron content [Fe(III) + Fe(II)] in different lots of IV iron formulations was as follows: iron gluconate, 1.4 and 1.8 %; ferumoxytol, 0.26 %; ferric carboxymaltose, 1.4 %; iron dextran, 0.8 %; and iron sucrose, 10.2, 15.5, and 11.0 % (average, 12.2 %). The average Fe(II) content in iron sucrose was, therefore, ≥7.5-fold higher than in the other IV iron formulations. Further studies are needed to investigate the relationship between Fe(II) content and increased risk of oxidative stress and infections with iron sucrose.

Mössbauer spectroscopy study of surfactant sputtering induced Fe silicide formation on a Si surface

The formation of Fe silicides in surface ripple patterns, generated by erosion of a Si surface with keV Ar and Xe ions and simultaneous co-deposition of Fe, was investigated with conversion electron Mössbauer spectroscopy, atomic force microscopy and Rutherford backscattering spectrometry. For the dot and ripple patterns studied, we find an average Fe concentration in the irradiated layer between 6 and 25at.%. The Mössbauer spectra clearly show evidence of the formation of Fe disilicides with Fe content close to 33at.%, but very little evidence of the formation of metallic Fe particles. The results support the process of ion-induced phase separation toward an amorphous Fe disilicide phase as pattern generation mechanism. The observed amorphous phase is in agreement with thermodynamic calculations of amorphous Fe silicides.

Microbial iron reduction and methane oxidation in subsurface sediments of the Arabian Sea

Arabian Sea is one of the most productive regions of the world's ocean with seasonal upwelling and a characteristic oxygen minimum zone. It receives a continuous input of windborne iron-rich dust which possibly stimulates phytoplankton productivity. A sediment core from this area, which is on the western continental margin of India in the Kerala-Konkan basin was studied from the surface to 63 m below seafloor, to establish the co-occurrence of microbial iron reducing activity and methane oxidation. Total bacterial abundance (TC), viable aerobic counts accounting for aerobic and facultative anaerobes (TVCa), viable anaerobic counts (TVCan), methane, sulfate, ferrous [Fe(II], hydroxylamine extractable iron and HCl extractable iron concentrations were measured. Average TC was 52.6 ± 29.8 × 105 cells g−1 sediment while TVCa and TVCan were an order less. Methane and sulfate concentrations were 1.3 ppm and 23.2 mM, respectively. Average Fe(II) concentration, hydroxylamine and HCl extractable Fe was 0.32 ± 0.26, 0.86 ± 1.44 and 1.90 ± 2.47 mmol g−1 sediment, respectively. Interestingly, Fe(II) significantly correlated with TVCan (r = 0.66, p ≤ 0.001).In the experimental tubes, the build-up of Fe(II) was accompanied by the disappearance of methane. Average methane concentration and Fe(II) concentration in the experimental sediment slurries was 0.56 ± 0.76 ppb and 0.50 ± 0.27 mmol g−1 sediment respectively. The microcosm experiment showed that Fe(II) determined was significantly higher (ANOVA, F = 6.74, p ≤ 0.014) after 5 days of incubation, thus implying microbial iron reducing activity. A strong negative linear correlation (p ≤ 0.001) of methane concentration with Fe(II) suggests that increasing activity of microbial iron reduction caused suppression in methane production. This is also indicative of the co-occurrence of iron reduction and methane oxidation in these sediments.

Drinking Water Quality at Academic Institutions of Tangail Municipality

An experiment was conducted to explore the drinking water quality at some selected academic institutions of Tangail municipality during the period of August to September, 2012. For this, an investigation was carried out to study the standard water quality parameters such as pH, EC, TDS, Pb, As, Fe and E. coli concentration of the five academic institutions. In general, there were no major differences found in pH, EC and TDS values among the studied stations and not exceeded the recommended thresholds. In case of heavy metal content, very trace amount of Arsenic (0.0071ppm) was recorded from all selected institutions. In contrast, average lead concentration (0.307xppm) was much higher than all acceptable standard limits and most risky position was taken by station-3 (0.46ppm). Similar to Pb, average Fe concentration (0.255ppm) was five times higher than the acceptable value of EU standard but not exceeded BD standard value. All the samples were E.Coli bacteria free.DOI: http://dx.doi.org/10.3329/jesnr.v6i1.22074 J. Environ. Sci. &amp; Natural Resources, 6(1): 247-252 2013

Identification and analysis of nutritional components of Enset (Ensete ventricosum) landraces suitable for corm production in Southern Ethiopia.

Enset (Ensete ventricosum) produces a nutritious human food from its vigorous pseudostem, corm and the stalk of inflorescence. Among the many different food made from Enset is 'Amicho ', which is a stripped corm of a younger plant of Enset, boiled and consumed in a way similar to Irish potato, sweet potato and cassava. Participatory Rural Appraisal (PRA) and formal survey were conducted in two weredas, one from each of two densely populated Enset growing zones (namely Sidama and Hadiya zones in the Southern Nations, Nationalities and Peoples Region of Ethiopia) to collect Enset landraces suitable for edible corm production and assess their nutrient contents. Eleven Enset land races suitable for edible corm production were identified and planted at Hawassa University experimental field for further investigation. The result of nutritional analysis showed a marked significant variability in the nutritional composition of the corms; this made the selection of nutritionally-rich Enset landraces possible. Large differences in protein content (0.90 to 2.39%), crude fibre (0.83 to 1.1%), carbohydrates (27.3 to 39.4 ), Fe (1.1 to 4.3 mg/100 gm), Zn (6.2 to 15.6 mg/100 gm) and Beta carotene (1 .5 to 22.2 μ g/100 gm) were recorded. 'Agade', 'Askala', and 'Gossalo' landraces had the highest protein, carbohydrates and Beta-carotene contents, respectively. 'Made' contained the highest crude fibre, Fe and Zn contents. The average protein content (1.4%) of corms of the Enset landraces was comparable to the average protein content of most root and tuber crops; whereas, the average Fe and Zn contents of corms of the Enset landraces were higher than the values reported for most root and tuber crops. The average energy and dry matter production rates of corms of the Enset landraces were about 124% and 169% higher, respectively than the average values for root and tuber crops. While Enset is conventionally perceived as having relatively low nutritional content when compared with other root and tuber crops, the present study provides evidence that, contrary to popular perception, there are excelling nutritional values of corms of the Enset landraces for humans. Keywords: Ensete ventricosum , landraces, corm, nutritional quality

Chemistry and mineralogy of clay minerals in Asian and Saharan dusts and the implications for iron supply to the oceans

Abstract. Mineral dust supplied to remote ocean regions stimulates phytoplankton growth through delivery of micronutrients, notably iron (Fe). Although attention is usually paid to Fe (hydr)oxides as major sources of available Fe, Fe-bearing clay minerals are typically the dominant phase in mineral dust. The mineralogy and chemistry of clay minerals in dust particles, however, are largely unknown. We conducted microscopic identification and chemical analysis of the clay minerals in Asian and Saharan dust particles. Cross-sectional slices of dust particles were prepared by focused ion beam (FIB) techniques and analyzed by transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDXS). TEM images of FIB slices revealed that clay minerals occurred as either nano-thin platelets or relatively thick plates. Chemical compositions and lattice fringes of the nano-thin platelets suggested that they included illite, smectite, illite–smectite mixed layers, and their nanoscale mixtures (illite–smectite series clay minerals, ISCMs) which could not be resolved with an electron microbeam. EDXS chemical analysis of the clay mineral grains revealed that the average Fe content was 5.8% in nano-thin ISCM platelets assuming 14% H2O, while the Fe content of illite and chlorite was 2.8 and 14.8%, respectively. In addition, TEM and EDXS analyses were performed on clay mineral grains dispersed and loaded on micro-grids. The average Fe content of clay mineral grains was 6.7 and 5.4% in Asian and Saharan dusts, respectively. A comparative X-ray diffraction analysis of bulk dusts showed that Saharan dust was more enriched in clay minerals than Asian dust, while Asian dust was more enriched in chlorite. Clay minerals, in particular nanocrystalline ISCMs and Fe-rich chlorite, are probably important sources of Fe to remote marine ecosystems. Further detailed analyses of the mineralogy and chemistry of clay minerals in global mineral dusts are required to evaluate the inputs of Fe to surface ocean microbial communities.

The association of LUR modeled PM2.5 elemental composition with personal exposure

Background and aimsLand use regression (LUR) models predict spatial variation of ambient concentrations, but little is known about the validity in predicting personal exposures. In this study, the association of LUR modeled concentrations of PM2.5 components with measured personal concentrations was determined. The elements of interest were copper (Cu), iron (Fe), potassium (K), nickel (Ni), sulfur (S), silicon (Si), vanadium (V) and zinc (Zn). MethodsIn Helsinki (Finland), Utrecht (the Netherlands) and Barcelona (Spain) five participants from urban background, five from suburban background and five from busy street sites were selected in each city (15 participants per city). Outdoor, indoor and personal 96-hour PM2.5 samples were collected by the participants over periods of two weeks in three different seasons (winter, summer and spring/autumn) and the overall average was calculated. Elemental composition was measured by ED-XRF spectrometry. The LUR models for the average ambient concentrations of each element were developed by the ESCAPE project. ResultsLUR models predicted the within-city variation of average outdoor Cu and Fe concentrations moderately well (range in R2 27–67% for Cu and 24–54% for Fe). The outdoor concentrations of the other elements were not well predicted. The LUR modeled concentration only significantly correlated with measured personal Fe exposure in Utrecht and Ni and V in Helsinki. The LUR model predictions did not correlate with measured personal Cu exposure. After excluding observations with an indoor/outdoor ratio of >1.5, modeled Cu outdoor concentrations correlated with indoor concentrations in Helsinki and Utrecht and personal concentrations in Utrecht. The LUR model predictions were associated with measured outdoor, indoor and personal concentrations for all elements when the data for the three cities was pooled. ConclusionsWithin-city modeled variation of elemental composition of PM2.5 did not predict measured variation in personal exposure well.

Removal of iron and manganese ions from abandoned neutral or alkaline mine drainage via ozone oxidation and micro-sand filtration: a pilot-scale operation

The objective of this study was to evaluate the ozone oxidation of dissolved Fe and Mn ions in abandoned neutral or alkaline mine drainage (NAMD) and the subsequent micro-sand filtration by conducting a pilot-scale operation with several ozone doses in an ozone reactor. The effects of the hydraulic retention time on the ozone oxidation were also investigated. The pH values were either neutral or slightly alkaline and the average Fe and Mn concentrations in the abandoned NAMD were 25.5 and 2.06 mg/L, respectively. The experiment results indicated that six-hour ozone oxidation with an ozone dose of 24.0g O3/h (i.e. initial ozone concentration: 3.53 mg O3/L) and subsequent micro-sand filtration could meet the drinking water quality standard (less than 0.3 mg/L) for both Fe and Mn in the micro-sand filter effluent. The hydraulic retention time of the ozone reactor at this ozone dose was 106 s, and the media of sand grains were between 0.4 and 0.7mm in diameter. The total dissolved solids, alkalinity, and SO42- concentrations of the influents were virtually unchanged in this pilot-scale operation. However, the oxidation-reduction potential of about 18 mV in influents increased rather gradually in effluents, and was recorded in the range of 185–210 mV during ozone oxidation. The ozone oxidation and subsequent micro-sand filtration under the operating conditions, in this study, appear to be among the desirable alternatives for the effective removal of dissolved Fe and Mn in the form of metal precipitates during ozone oxidation. This alternative could prevent metal precipitates from settling at the bottom of local water channels by removing them before they are discharged into streams.

Spatial and particle size distributions of atmospheric dissolvable iron in aerosols and its input to the Southern Ocean and coastal East Antarctica

AbstractTo characterize atmospheric dissolvable iron over the Southern Ocean (SO) and coastal East Antarctica (CEA), bulk and size‐segregated (0.056–18 µm in diameter) aerosols were collected from 34°S, 109°E to 69°S, 76°E and between 69°S, 76°E and 66°S, 110°E during a cruise during November 2010 to March 2011. Aerosols were analyzed for total dissolvable Fe and Fe(II) by UV/Visible spectroscopy and total Fe by inductively coupled plasma‐mass spectrometry. The average concentrations of total Fe were 19 ng m−3 (range: 10–38 ng m−3) over the SO and 26 ng m−3 (range: 14–56 ng m−3) in CEA. The average Fe(II) concentrations were 0.22 ng m−3 (range: 0.13–0.33 ng m−3) over the SO and 0.53 ng m−3 (range: 0.18–1.3 ng m−3) over CEA; the total dissolvable Fe followed the same trend. Over the SO, a single‐peak size distribution of Fe(II) existed. Over CEA, a bimodal size distribution of Fe(II) appeared, with the first peak at 0.32–0.56 µm and the second peak at 5.6–10 µm. Higher Fe concentrations over CEA than over the SO and the existence of coarse mode Fe(II) over CEA suggest potential dust sources in Antarctica. The fractional Fe(II) solubility ranged from 0.58% to 6.5% and decreased with total Fe concentration increase. The estimated atmospheric fluxes of Fe(II) were 0.007–0.092 mg m−2 yr−1 over the SO and 0.022–0.21 mg m−2 yr−1 in CEA. Total dissolvable Fe fluxes were 0.007–0.52 mg m−2 yr−1 over the SO. The atmospheric dissolvable Fe input contributes to the dissolved Fe pool in the SO surface waters.

Pollution Scenario due to Discharge of Effluent from Agrochemicals and Pesticides Manufacturing Industries of Dombivali Industrial Belt of Mumbai, India

The paper deals with monitoring of pollution arising due to agrochemicals and pesticides manufacturing industries located along the Dombivali industrial belt of Mumbai, India. The study was carried for the period of one year from June, 2012 to May, 2013 to study the level of toxic heavy metals and the physico-chemical properties of waste water effluents discharged from the above industries. The average concentration of Cu, Ni, Cr, Pb and Zn was found to be maximum of 29.86, 0.90, 1.16 and 1.19 ppm respectively in summer season, while average Fe concentration was maximum of 51.10 ppm in winter season. The average pH value of the effluent was found to be maximum of 12.95 in summer season, while average conductivity value was maximum of 21085 µmhos/cm in rainy season. The majority of physco-chemical parameters like alkalinity, hardness, salinity, chloride, cyanide, phosphate, total solid, BOD and COD content were found to be maximum in summer season having the average values of 1918, 186, 4, 11.20, 0.07, 81, 6391, 685 and 2556 ppm respectively. The average DO content was found to be low of 4.5 ppm in winter season. It was observed that the concentration level of majority of the toxic heavy metals and physico-chemical properties were above the tolerable limit set for inland surface water. The results of present study indicates that the existing situation if mishandled can cause irreparable ecological harm in the long term well masked by short term economic prosperity due to extensive industrial growth