Aluminum Levels Research Articles

Soil acid Management using Biochar: Review

Soil acidity affects the growth of crops because acidic soil contain toxic levels of aluminum and manganese and characterized by deficiency of essential plant nutrients such as P, N, K, Ca, Mg, and Mo.

Growth study of rice genotypes to varying levels of aluminum

The investigation was carried out to study the growth of seven rice genotypes (Oryza sativa L.) under different levels of aluminum in the stress physiology laboratory, Department of Crop Physiology, Assam Agricultural University. Results obtained from the investigation revealed that higher levels of aluminum significantly influenced the growth of the genotypes. However, some tolerant genotypes viz. Rajamani and Rene Nepung Aam showed a better performance than the other genotypes by maintaining the Leaf area index, Specific leaf weight, Root biomass accumulation and other yield attributing characters (Panicle weight, Harvest index). Considering all these characters Rajamani and Rene Nepung Aam may be considered as tolerant genotypes under high aluminium conditions.

Aluminium-enriched metal-poor stars buried in the inner Galaxy

Stars with higher levels of aluminium and nitrogen enrichment are often key pieces in the chemical makeup of multiple populations in almost all globular clusters (GCs). There is also compelling observational evidence that some Galactic components could be partially built from dissipated GCs. The identification of such stars among metal-poor field stars may therefore provide insight into the composite nature of the Milky Way (MW) bulge and inner stellar halo, and could also reveal other chemical peculiarities. Here, based on APOGEE spectra, we report the discovery of 29 mildly metal-poor ([Fe/H] ≲ −0.7) stars with stellar atmospheres strongly enriched in aluminium (Al-rich stars: [Al/Fe] ≳ +0.5), well above the typical Galactic levels, located within the solar radius toward the bulge region, which lies in highly eccentric orbits (e ≳ 0.6). We find many similarities for almost all of the chemical species measured in this work with the chemical patterns of GCs, and therefore we propose that they have likely been dynamically ejected into the bulge and inner halo from GCs formed in situ and/or GCs formed in different progenitors of known merger events experienced by the MW, such as the Gaia-Sausage-Enceladus and/or Sequoia.

Effects of Organic Materials Obtained from Different Tree Species on Some Chemical Parameters of Water Quality (Study Case of Andirin-Akifiye Forest Management Unit)

Mineral substance concentrations are very important in terms of the levels of chemical quality in drinking water. A highly important source of minerals in water comes from the litter layer of the forest floor which is also a source of organic matter. This research investigates the contribution of organic litter formed in pure pine, cedar and beech forests to the quality parameters of water in the Andirin District of Kahramanmaraş province. A total of 90 organic matter samples were systematically collected from three different forest ecosystems. Some chemical properties of water solution were obtained from the organic matter using the ICP-OES device. This revealed that aluminum, boron, zinc, iron, cadmium, calcium, cobalt, magnesium, manganese, nickel and potassium parameters were present in the water. In addition, pH, EC and temperature measurements were taken. The results revealed lower amounts of chemicals in the waters obtained from the dead vegetation covers of the beech forests, showing elements such as aluminum, iron, magnesium, cobalt, and nickel levels to be 0.146 mg; 0.114 μg; 5.54 mg; 0.0006 μg and 0.0054 μg, respectively, compared to waters obtained from cedar and pine forest ecosystems. It was found that different organic materials had significantly different mineral concentrations affecting the chemical quality of the water. However, waters affected by the dead vegetation cover of the forest ecosystem were determined to comply with the standards of drinking and irrigation water according to current regulations. 

Ultramafic Zoned Complexes of the Urals and Siberia: New Geochemical Evidence of Magmatic Origin

AbstractUltramafic (dunite‐clinopyroxenite) complexes with platinum mineralization are common in different tectonic settings. Among them are zoned complexes of the Ural‐Alaskan type, zoned complexes of platforms (Konder massif, Siberia), as well as layered intrusion complexes (Gulin massif, Siberia). In determining the genesis of these formations, an important role belongs to the study of melt inclusions and rock‐forming minerals, including clinopyroxene.Clinopyroxenes of the ultramafic complexes exhibit a general trend of evolution, expressed as a decrease in magnesium content (Mg# = 0.95 to 0.7) and an increase in the contents of titanium and aluminum oxide (0–4.5% and 0.5–7.0%, respectively) in the dunite ‐ clinopyroxenite series. In the coordinates of Ti ‐ AL (IV) the clinopyroxenes of the Ural‐Alaskan complexes of the Platinum belt form a linear trend of compositions with a slight increase (0–0.03 f.u.) in the titanium contents. In comparison with them the clinopyroxenes of the zoned platform complexes (Konder massif) demonstrate a shift in the trend of compositions, due to an increase in the titanium content to the moderate (0.05 f.u.) values. For the layered intrusions (Gulin pluton), it is typical another trend of clinopyroxene compositions with significantly higher titanium contents (0.04–0.12 f.u.) at the similar level of aluminum. Clinopyroxene compositions of zoned complexes of the Platinum belt are “controlled” by the area of boninites and tholeites of island arcs, and the zoned complexes of platforms by the areas of island arc tholeites and sub‐alkaline intraplate basalts. Clinopyroxenes of the layered intrusions are located in the field of compositions of alkaline intraplate or MORB basalts.The geochemical study of clinopyroxenes, performed by laser ablation method (LA‐ICP‐MS) at the University of Kanazawa (Japan) and the Institute of Geology and Geochemistry of the UB RAS (Zaitseva et al., 2018), established the following features: (1) In ultrabasites of zoned complexes of the Urals and Siberia (Konder massif), clinopyroxene is characterized by an arc‐shaped distribution of rare earth elements with increasing contents from dunites to pyroxenites at a relative deficit of heavy REE (LaN/YbN = 1.2–5.4). In magnetite clinopyroxenites (enriched REE), its composition is close or identical to that in orthoclase‐bearing pyroxenites (tylaites). Negative anomalies of lead, zirconium, hafnium, and titanium, as well as positive anomalies of strontium, are typical for clinopyroxene zoned complexes. (2) In ultrabasites of layered intrusions (Gulin massif) clinopyroxene is characterized by higher level of light lanthanides with a steeper slope of the REE distribution spectra (LaN/YbN = 8–13). Lead, zirconium and hafnium anomalies are also inherent in the compositions; unlike the zoned complexes a weak negative anomaly of strontium and a positive anomaly of titanium are observed.Using the partition coefficients between clinopyroxene and the melt, the compositions of parental melts for ultramafic complexes were calculated. In general, these model melts are characterized by oblique spectra of compositions typical of island arc and intraplate environments (Fig. 1). Model melts corresponding to the Ural‐Alaskan‐type zoned complexes (Platinum belt) show low levels of REE with a noticeable deficiency of heavy lanthanides (LaN/YbN = 8–25). By their high (≥ 2) CaO/Al2O3 ratio, they are close to ankaramite type island arc melts, differing by a steeper slope of the REE distribution spectra. Model melts corresponding to the zoned platform complexes (Konder massif) demonstrate a higher level of REE content and a deficit of heavy REE (LaN/YbN = 38), with a similar distribution pattern. At a lower Ca/Al ratio (0.4–1.9), they are close to melts of the picritic type. In comparison with them, model melts corresponding to the layered intrusions (Gulin massif) demonstrate a significantly higher level of REE and a steeper slope of the distribution spectra (LaN/YbN = 67–103), typical of alkaline mechmitic melts. In general, the results of the mineralogical and geochemical study of clinopyroxenes of ultramafic complexes correlate well with the data on melt inclusions in spinels from dunites (Simonov et al., 2017).

Effect of parboiling on toxic metal content and nutritional composition of three rice varieties locally produced in Nigeria

Parboiling of rice is a common cooking method and its effect on quality of rice is sparse in the existing literature. The current study was designed to evaluate the effect of parboiling on levels of nutritional components and toxic metals of rice locally produced and consumed in Nigeria. Three varieties of rice were considered and each sample divided into two portions for parboiling and conventional cooking procedures using standard methods. The rice flours were prepared for proximate analysis, amino acid and vitamin profiles using HPLC, while minerals and toxic metals were analyzed by inductively-coupled plasma optical emission spectrometry (ICP-OES). Parboiling significantly (p<0.05) increased ash and fiber contents of the rice samples, whereas, lipids considerably (p<0.05) reduced compared to the unparboiled rice. The levels of some of the essential amino acids, vitamins were significantly reduced by parboiling. Parboiling markedly (p<0.05) reduced levels of aluminium, nickel, chromium and manganese; cadmium, lead and arsenic levels were however increased significantly by parboiling. This study reveals that parboiling may significantly affect components of cooked rice and exert impact that may alter health status. Future studies are suggested to clarify further the effect of parboiling on toxic metals in staple food like rice.

The tolerance of oil palm (Elaeis guineensis) seedlings to Al stress is enhanced by citric acid and natural peat water

Abstract. Hidayah AN, Yahya S, Sopandie D. 2020. The tolerance of oil palm (Elaeis guineensis) seedlings to Al stress is enhanced by citric acid and natural peat water. Biodiversitas 21: 4850-4858. Management technology on soil containing high levels of Aluminum (Al) toxicity is still needed to be developed so that the growth and development of plants will be optimum. The aims of the research were to investigate the response of oil palm seedlings (Elaeis guineensis Jacq.) toward aluminum stress, and to evaluate the effects of several exogenous compounds to improve the tolerance of oil palm. The research was conducted from September 2018 to March 2019 at PT Gunung Sejahtera Ibu Pertiwi, Central Kalimantan. This research consisted of two nutrient culture experiments, namely: Al toxicity on oil palms seedlings and the role of various exogenous compounds to improve plant tolerances. The results revealed that the solution at concentrations of 400 μM, 800 μM, and 1600 μM of Al significantly inhibited root growth, increased MDA levels, decreased the photosynthesis rate, activity of CAT and APX. Therefore, a solution at concentration of 400 μM of Al can be used as the selection level of Al tolerant oil palm varieties on nutrient culture. Ethephon at concentrations of 25 ppm, 50 ppm, and 100 ppm inhibited root and shoot growth, increased MDA levels but reduced the photosynthesis rate, chlorophyll content, APX, and CAT activity. Addition of 25 ppm and 50 ppm of citric acid, 200 ppm and 300 ppm of peat water significantly increased root length, root dry weight, photosynthesis rate, chlorophyll content, carotenoids, CAT, and APX activities as MDA levels decreased. Addition of citric acid and peat water enabled seedlings of oil palm to improve their tolerance to Al stress on nutrient culture.&#x0D;

Exploratory analysis in the evaluation of stress due to aluminum presence in Physalis angulata L. and multielement determination by microwave-induced plasma optical emission spectrometry (MIP OES).

The present work aimed to analyze the mineral nutrition of Physalis angulata L. under stress by aluminum in the nutrient solution. The treatments consisted of five different concentrations of aluminum in the nutrient solution (0, 0.04, 0.08, 0.12, and 0.16mmolL-1) in the AlCl3 form. The plants were exposed to Al for 30days. Subsequently, nutritional and aluminum analyses were performed on plant tissue. The data were submitted to analysis of variance (p< 0.05), and, in case of significance, the regression study was performed as well as hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used. The formation of four groups occurred, where we can observe the similarity and differences in the treatments between them. The separation of the treatments into groups reflected the heterogeneity of the treatments about the aluminum levels in the nutrient solution, evidencing its phytotoxicity level in Physalis angulata plants. Among the analyzed variables, P, K, Ca, Mg, Fe, Mo, and Zn were the most influential ones demonstrated by principal component analysis (PCA). The stress of 0.16mmolL-1 of Al increased the phosphorus contents in the stems and roots and the potassium, copper, and molybdenum contents in all parts of the plants. In contrast, Al reduced the levels of calcium, magnesium, iron, and zinc in P. angulata plants. Iron being the micronutrient that showed the largest reduction, followed by zinc in the leaves. The highest levels of aluminum were found in the roots.

Environmental agate mining impacts and potential use of agate residue in rangeland

The impacts of agate exploitation on soils and the adjacent landscapes are poorly understood. In addition, agate processing produces residues whose potential use in agriculture must be evaluated, in order to develop cleaner production practices. The aims of this study were: i) to estimate the effects of agate mining on the soil and the adjacent landscapes; ii) to evaluate the chemical and mineralogical composition of agate; and iii) to test the use of agate powder in native grassland soils. Remote sensing techniques were used to map the soil uses around mine sites to evaluate their interference with the adjacent landscapes. Agate powder, an industrial residue, was chemically and mineralogically characterized, and its effects on soil were tested. We used 0; 1000; 2000; 4000 and 8000 kg ha−1 of agate powder applied to natural grassland in a randomized block design experiment with four replications. The application was repeated in the 47th week after the initial application. The findings showed that the mines had a weak effect on the surrounding landscapes (i.e., native forest, native pasture and annual crops). However, locally, the soil organic matter contents of mine areas decreased, while the potential acidity and toxic aluminum levels increased. Low doses of agate used in rangeland soils had a healthy effect on soil pH, potential acidity and toxic aluminum, while high doses decreased the available K in soil and in the dry matter of the rangeland plants. Little effects were observed on the Si content in the soil or in the plants. Finally, our study highlights that agate exploitation has local impacts on the soil and adjacent landscapes and that agate residue may be used in rangelands at low doses with beneficial results for some soil attributes. These results consists in cleaner production practices for beneficing industry, farmers and environmental since preserving rangeland areas.

Interchangeable neck failures of bi-modular femoral stems in primary total hip arthroplasty cannot be predicted from serum trace element analysis.

Revision of a well-fixed stem due to unexpected modular neck fracture is a catastrophe for the patient and a challenge for the surgeon. This study aimed to test the possibility of predicting interchangeable neck fracture from serum levels of the stem/neck alloy-consisting metals. Nineteen patients at high risk for interchangeable neck fracture were randomly selected out of a cohort of 680 bimodular stems made from Ti6Al4V alloy. Serum levels of titanium, aluminium and vanadium were determined. Nine age- and gender-matched patients were used as controls. Mean serum levels of Ti were 6.04 ± 2.52μg/L, of Al 3.89 ± 1.68μg/L and of V 0.07 ± 0.04μg/L in the high-risk group, and 8.22 ± 4.74μg/L, 4.99 ± 3.98μg/L and 0.27 ± 0.44μg/L in the low-risk group, respectively. No statistically significant differences were found between the groups. Interchangeable neck fracture of bimodular femoral stems cannot be predicted from serum trace element analysis.

Effect of feather compost on soil chemical indicators in CCN-51 cocoa plantation (Theobroma cacao L.)

Introduction. Organic management of cocoa accounts for 60% of production in Peru and large amounts of compost prepared with different inputs are used, in order to improve the quality of the soil and cocoa yields. Objective. Evaluated the effect of the application of chicken feather compost on the main soil chemical indicators in a cocoa plantation CCN-51 un the Town of Nuevo Progreso, province of Padre Abad in the Ucayali-Peru region was evaluated. Materials and methods. A randomized complete block design was used, with four treatments and four repetitions where: FC1 was an absolute witness, FC2 feather compost at a rate of 2,000 kg. ha-1, FC3 feather compost at a rate of 4,000 kg. ha-1 and FC4 feather compost at a rate of 6 000 kg. ha-1. The main chemical indicators of soil quality were evaluated: hydrogen potential (pH), organic matter (OM), total nitrogen (N), available phosphorus (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+) , aluminum (Al3+), available cadmium (Cd2+), changeable acids (AC) and cation exchange capacity (CEC). Results. The results showed a decrease in exchangeable aluminum and changeable acidity and increases in organic matter, nitrogen, phosphorus, and potassium, depending on the proportion of compost applied, these indicators presented significant differences (p &lt;0.05); The pH, calcium and cadmium available did not show significant differences (p &lt;0.05). Conclusion. Feather compost (FC) significantly improved the levels of OM, N, P and K+, indicators that define soil quality and reduce aluminum levels, the latter of utmost importance in acidic soils.

Aluminum and Neurofibrillary Tangle Co-Localization in Familial Alzheimer's Disease and Related Neurological Disorders.

Background:Protein misfolding disorders are frequently implicated in neurodegenerative conditions. Familial Alzheimer’s disease (fAD) is an early-onset and aggressive form of Alzheimer’s disease (AD), driven through autosomal dominant mutations in genes encoding the amyloid precursor protein and presenilins 1 and 2. The incidence of epilepsy is higher in AD patients with shared neuropathological hallmarks in both disease states, including the formation of neurofibrillary tangles. Similarly, in Parkinson’s disease, dementia onset is known to follow neurofibrillary tangle deposition.Objective:Human exposure to aluminum has been linked to the etiology of neurodegenerative conditions and recent studies have demonstrated a high level of co-localization between amyloid-β and aluminum in fAD. In contrast, in a donor exposed to high levels of aluminum later developing late-onset epilepsy, aluminum and neurofibrillary tangles were found to deposit independently. Herein, we sought to identify aluminum and neurofibrillary tangles in fAD, Parkinson’s disease, and epilepsy donors.Methods:Aluminum-specific fluorescence microscopy was used to identify aluminum in neurofibrillary tangles in human brain tissue.Results:We observed aluminum and neurofibrillary-like tangles in identical cells in all respective disease states. Co-deposition varied across brain regions, with aluminum and neurofibrillary tangles depositing in different cellular locations of the same cell.Conclusion:Neurofibrillary tangle deposition closely follows cognitive-decline, and in epilepsy, tau phosphorylation associates with increased mossy fiber sprouting and seizure onset. Therefore, the presence of aluminum in these cells may exacerbate the accumulation and misfolding of amyloidogenic proteins including hyperphosphorylated tau in fAD, epilepsy, and Parkinson’s disease.

Effect of metallothionein 1A rs8052394 polymorphism on lead, cadmium, zinc, and aluminum levels in factory workers.

Metallothioneins (MTs) are low molecular weight cysteine-rich, metal-binding proteins. They are involved in transportation and detoxification of heavy metals, homeostasis of essential metals, and as antioxidation against reactive oxygen species. Polymorphisms in a gene may increase or decrease the expression efficiency of a gene. This study aimed to determine the genetic effect of MT1A rs8052394 on lead (Pb), cadmium (Cd), zinc (Zn), and aluminum (Al) levels in factory workers. The study included 100 occupationally heavy metal exposed workers from different factories around Jodhpur. Pb, Cd, Zn, and Al levels were measured by atomic absorption spectrophotometry. Individuals with the GG genotype had lower Pb, Zn, and Al levels and higher Cd levels than AA and AG genotypes. The genotyping of MT1A rs8052394 was done by the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). The mean ± standard deviation of Pb, Cd, Zn, and Al was 5.88 ± 13.28 µg/dL, 3.52 ± 1.25 µg/L, 16.45 ± 16.69 µg/dL, and 58.92 ± 58.91 µg/L, respectively. A significant association was found between single-nucleotide polymorphisms (SNPs) of MT1A gene and Cd (p = 0.006) and with Zn levels (p = 0.031) but no association found with Pb and Al levels. Among the study population, 78 participants were homozygote major (AA), 19 were heterozygote (AG), and 3 were homozygote minor (GG). The χ 2 test presented the genotypic distribution of all three genotypes under the Hardy-Weinberg equilibrium (p > 0.05). The frequency of the A allele was 87.5% (175) and the G allele was 12.5% (25). To conclude, polymorphism in rs8052394 of the MT1A gene is associated with increased metal accumulation which in turn may lead to increased toxic effects in the exposed individuals. Factory workers thus, should be more cautious about protecting their health against the toxic effects of heavy metals.

Heavy metals and potential risks in edible seaweed on the market in Italy

The seaweed food has always been important in Asia, but recently increased in the Western diet.Superfood known for health benefits and rich in essential elements, can also accumulate high contents of heavy metals and iodine from the environment, becoming a health hazard. In particular for iodine, an appropriate labelling of seaweed is needed to warn the consumer of the potential risks. The aim of the study was to analyze the content of 20 heavy metals in seaweeds, distributed in Italy, by ICP-MS, also determining iodine and arsenic (total and inorganic fraction).A total of 72 samples of European and Asian seaweed of 8 genera were analyzed and the results correlated the content of heavy metals to genus, geographical origin and type of sample; 8.33% of the products lacked in the label of the indications of allergens, while 9.72% had irregularities in the label language.The highest concentration of elements was found in the Rhodophyta. The Aluminum level was the highest in the mixed seaweed (165.39 mg/kg) and for the Cadmium in the Asian seaweed (1.16 mg/kg). The amounts of Iron, Zinc and Magnesium, was highest in the Asian seaweed. The values of Arsenic (total and inorganic contents) were compared with the limits: 2.78% exceeds France and USA limits for inorganic, while higher content of total was found in Phaeophyta, which also showed the highest Iodine content (6770.80 mg/kg) that can be dangerous if not reported correctly in the label.

High-Dose Aluminum Exposure Further Alerts Immune Phenotype in Aplastic Anemia Patients

This study explored the relationship between immunological status and clinical characteristics of aplastic anemia (AA) patients to plasma aluminum levels, which were increased after constant exposure to high levels of this metal. Sixty-two AA patients (33 cases with high and 29 cases with low or no exposure to aluminum) and 30 healthy controls were selected for this study. Aluminum in human albumin solution was measured by inductivity coupled plasma mass spectrometry. IL-10, IL-12, IL-17, and INF-γ levels were measured by enzyme-linked immunosorbent assay. The distribution of lymphocyte subsets were determined by flow cytometry. The expression levels of immunoglobulins and complement C3 and C4 were also measured. Exposure to high aluminum raised the levels of serum aluminum in AA patients (P < 0.01). The levels of hemoglobin and complement C4 were lower in AA patients with high aluminum exposure (P < 0.05 and < 0.01, respectively). The percentage of CD4+ T cells and the ratio of CD4+/ CD8+T cells in peripheral blood in AA patients with high aluminum exposure were higher compared with control AA patients (P < 0.05 in both cases), while the percentage of CD8+ T cells was significantly lower than that in non-aluminum–exposed AA patients (P < 0.05). Compared with non-aluminum–exposed AA patients, the level of IL-10 in the high aluminum–exposed AA group was significantly higher (P < 0.05 in both cases). The immunological and clinical characteristics of AA patients from regions of high aluminum exposure are different to those in from non-aluminum areas. These results suggest that high aluminum exposure alters the immune system in patients suffering from AA.

Investigation of process by-products during the Selective Laser Melting of Ti6AL4V powder

This paper investigates the formation of process by-products during the laser processing of titanium alloy powders by Selective Laser Melting (SLM). The study was carried out during the printing of Ti6AL4V parts using a production scale SLM system (Renishaw RenAM500 M). By-product particles were obtained on the surface of powder removed from the area around where the pulsed laser powder treatments had been carried out. The process by-products examined in this study were damaged Ti6AL4V particles along with condensate. The particles were found to exhibit deshelling, fracture, and collision damage. Based on TEM and SEM examination, the condensate particles were found to have sizes in the nanoscale range and exhibited morphologies, similar to those reported in the literature for welding condensates. Energy-dispersive X-ray spectroscopy (EDX) analysis indicated that the condensate formed from processing Ti6AL4V, exhibited a higher level of aluminum than that obtained for the alloy itself, lower levels of titanium with minimal vanadium levels, were also obtained. This may indicate that the alloy partially decomposes, with the emission of the lower melting point alloying element. The use of an in-situ melt pool monitoring system (called Renishaw InfiniAM Spectral), was evaluated for detecting the presence of these by-product particulates, based on photodiode measurements of the melt pool emissions, along with a camera-based imaging of visual per layer conditions. A reduction in the intensity of infrared emissions was detected, in areas where suspected spatter particles had been redeposited. Thus, demonstrating that process monitoring can be used for the in-situ detection of particulate defects formed during printing.

Yetişkinlerde Konserve Balık Tüketimine Bağlı Ağır Metal Maruziyet Riskinin Değerlendirilmesi

Amaç: Bu çalışma, Ankara piyasasında satılan 7 farklı türe ait (ton, sardalya, somon, uskumru, hamsi, alabalık ve levrek) 66 adet konserve balığın ağır metal içeriklerini analiz etmek ve yetişkin bireylerin ağır metal maruziyet düzeylerinin saptanarak risk değerlendirmesini yapmak amacıyla planlanmış ve yürütülmüştür.&#x0D; Gereç ve Yöntem: Tüm konserve balık örneklerinin ICP-MS (indüktif eşleşmiş plazma-kütle spektrometresi) cihazında kurşun (Pb), kadmiyum (Cd), alüminyum (Al) ve arsenik (As) analizleri yapılmıştır. Yetişkin bireylerin haftada 2 porsiyon konserve balık tüketmeleri halinde maruz kalacakları Pb, Cd, Al ve As düzeyleri hesaplanmıştır.&#x0D; Bulgular: Analiz edilen balıklar içerisinde Pb ve Cd açısından en yüksek içeriğe sahip olan tür ton balığıdır (sırasıyla; 0.12±0.16 mg/kg, 6.41±4.98 mcg/kg). Alüminyum açısından en yüksek konsantrasyona sahip konserve hamsi iken (1.91±0.15 mg/kg), As açısından en yüksek düzey sardalya da (2.16±1.13 mg/kg) belirlenmiştir. Araştırma sonuçlarına göre yetişkin bireylerde Pb, Cd, Al ve As maruziyetinin Besin ve İlaç İdaresi (FDA) ve Gıda Katkı Maddeleri Ortak FAO/WHO Uzmanlar Komitesi (JECFA) tarafından belirlenen üst limitlerin altında olduğu saptanmıştır.&#x0D; Sonuç ve Öneriler: Günümüzde konserve balıklar ulaşılabilirlik ve tüketim kolaylığı nedeniyle tercih edilmektedir. Ancak taze veya konserve balıklar diyetimizde ağır metaller yönünden de potansiyel bir risk olarak gösterilmektedir. Bu çalışmada, piyasada satılan farklı içeriğe sahip konserve balıkların farklı düzeylerde ağır metal içeriğine sahip olduğu ve yetişkinlerin farklı düzeylerde ağır metale maruz kaldığı saptanmıştır. Piyasada satışa sunulan farklı türde konserve balıkların günlük tüketim miktarlarına göre farklı yaş gruplarındaki bireylerin ağır metal maruziyet riskini değerlendiren çalışma sayısı oldukça azdır. Bu konuda daha kapsamlı çalışmaların yapılması gerekmektedir.

Characteristics of carbide-free medium-carbon bainitic steels in high-stress abrasive wear conditions

This study encompasses a comprehensive account of the abrasive wear properties of carbide-free, ultrahigh-strength bainitic steels processed through ausforming at three different temperatures well below the recrystallization stop temperature followed by bainitic transformation at temperatures close to the Ms temperature. Five medium-carbon, high-silicon compositions were designed for the study by suitably varying the alloying levels of carbon, vanadium, niobium, molybdenum, and aluminum. While ausforming at lower temperatures enabled a large number of nucleation sites leading to significant refinement of bainitic laths, the decomposition of austenite at relatively low transformation temperatures was accelerated due to the presence of a high dislocation density, thus enabling completion of bainitic transformation in a reasonable length of time. The steels were characterized in respect of microstructural features and mechanical properties, besides evaluation of wear resistance through a high-stress abrasive wear testing method with natural granite abrasives. The microstructures comprised different fractions of bainitic ferrite and/or granular bainite (56–68%), martensite (0–25%), besides a significant fraction of retained austenite (20–34%) manifesting as pools and also interlath films, depending on the ausforming conditions and subsequent cooling paths. A tensile strength of 1900 MPa level was achieved with hardness exceeding 500 HV for the medium-temperature ausformed steel containing a high carbon content that also showed lowest mass loss in the wear test. The hardness-to-mass loss ratio appeared highly promising with some of the carbide-free bainitic steels on par with or better than the reference martensitic steel. The high work-hardening capability as a consequence of the strain-induced austenite to martensite transformation was considered as the main factor for the superior abrasive wear resistance of the carbide-free bainitic steels.

Sandstone Acidizing Using a Low-Reaction Acid System

Abstract Sandstone acidizing is the process of removing the damage from sandstone reservoirs to restore the well productivity/injectivity to its original or expected rates. It differs from carbonate acidizing in which a substantial portion of the rock is dissolved. Stimulating sandstone with mud acid HF/HCl may cause many problems as sandstone is a clastic sedimentary rock that consists mainly of quartz, silica minerals, feldspars, clays, and minor quantities of zeolite and chlorites. When conventional mud acid reacts with rock some sensitive components of sandstone get cemented by silica, calcite, or iron oxides. This happens due to the different precipitation reactions that take place and form fluosilicates, calcium fluorides, silica-gel filming, and even colloidal silica-gel compounds. In this work, two chelating agents, hydroxyethylenediaminetetraacetic acid (HEDTA) and diethylenetriaminepentaacetic acid (DTPA), were used to stimulate Berea sandstone cores. Berea sandstone cores were scanned using the XRD to quantify their mineralogical composition. Different pore volumes of 0.6M HEDTA and 0.6M DTPA were used as a preflush followed by different concentrations of HF as a main flush. For the post-flush stage, ammonium chloride was used to flow back the cores and measure their permeability. The levels of calcium, magnesium, aluminum, and iron ions in the effluent samples were measured using inductively coupled plasma (ICP) to assess the ability of each chemical to leach these different ions. Both HEDTA and DTPA showed a strong capability of chelating calcium, iron, and magnesium ions from the sandstone cores while the amounts of chelated aluminum ions were quite small. Once starting the injection of the used chelating agents, the permeability of the core got enhanced gradually. The higher amounts of the chelating agents resulted in better the cores permeability. However, DTPA showed a better permeability enhancement than HEDTA due to its stronger ability to chelate the calcium, iron, magnesium, and aluminum ions. Adding HF as the main flush initiates different reactions with the clay and silica minerals of the Berea sandstone cores. This caused a reduction in the permeability due to the formation of some precipitates such as fluosilicates and calcium fluorides. Therefore, it is recommended to use a very low concentration of HF while treating the Berea sandstone.

Environmental Quality and Cytogenotoxic Impact of the Waters of a Stream Receiving Effluents from Tannery Industry

The Estância Velha stream integrates the Sinos River Basin that provides drinking water in one of the most important Brazilian centers, the “Capital of tanneries,” and it receives effluents from tannery industries. In Brazil, water quality is monitored only through physicochemical and microbiological parameters, and considering the biomarkers’ importance in complementing the analysis, the present study was aimed at evaluating the environmental quality of the Estância Velha stream also through cytogenotoxic criteria, at the stream source (site 1), as well as upstream (site 2) and downstream (site 3) of the demographically most dense area. The results for dissolved oxygen, color, total phosphorus, silver, and thermotolerant coliforms classified the Estância Velha stream as class 4 in general; that is, the water is suitable only for navigation and to landscape harmony. Overall, the water was classified as poor by Water Quality Index (WQI) and as hypereutrophic by Trophic State Index (TSI). The main genotoxic alterations (micronuclei and nuclear buds) were observed in site 2, in which were obtained the highest levels of aluminum, silver, iron, and manganese. Despite this, most of the effluents released from the region are not treated prior to being discharged into the stream, suggesting the requirement for effluent treatment to ensure the quality of the water source available.