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1.
J Environ Sci (China) ; 97: 35-44, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933738

RESUMO

Few studies have been carried out to connect nutrient recovery as struvite from wastewater and sustainable utilization of the recovered struvite for copper and zinc immobilization in contaminated soil. This study revealed the effect of struvite on Cu and Zn immobilization in contaminated bio-retention soil in the presence of commonly exuded plant organic acids. The research hypothesis was that the presence of both struvite and organic acids may influence the immobilization of Cu and Zn in soil. The outcome of this research confirmed that more than 99% of Cu and Zn was immobilized in bio-retention filter media by struvite application. Water-soluble Cu and Zn concentrations of struvite treated soil were less than 1.83 and 0.86 mg/kg respectively, and these concentrations were significantly lower compared to the total Cu and Zn content of 747.05 mg/kg in the contaminated soil. Application of struvite to Cu- and Zn-contaminated soil resulted in formation of compounds similar to zinc phosphate tetrahydrate (Zn3(PO4)2•4H2O) and amorphous Cu and Zn phases. Struvite was effective in heavy metal remediation in acidic soil regardless of the presence of Ca impurities in struvite and the presence of plant organic acids in soil. Overall, this study revealed that struvite recovered from wastewater treatment plants has potential for use as an amendment for heavy metal remediation in contaminated bio-retention soil.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Cobre , Solo , Estruvita , Zinco
3.
Sci Total Environ ; 740: 139648, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927528

RESUMO

Soybean is recognized as one of the most important prospective protein sources for human nutrition under conditions of climate change and population growth. Occurrence of Se and Zn deficiency in vast areas over the globe inhabited by up to 2 billion people, induced search for a comprehensive solution to these problems through the efficient Se/Zn biofortification of soybean seeds (beans). To assess the Se/Zn accumulation efficiency and the physiological status of soybean plants, a pot experiment on Se and Zn enrichment in beans was conducted. It consisted of applying 15 different Se-deficient soil treatments with these elements during the flowering phase, alone or in dose combinations. Application of Se alone, besides Se accumulation in soybean, reduced Zn uptake from soil, but caused alterations in Zn translocation, and its multiple enrichment in beans. Addition of Zn alone promoted both Zn and Se enrichment in beans. Joint Se/Zn application in increasing doses appeared to have a strong synergistic effect on accumulation of these elements in beans and enhanced the physiological functions of the soybean. This manifested itself in the growth of photosynthetic production and soybean biomass, and in the improvement of lipid peroxidation status (REC, MDA and proline content indices). Toxicity symptoms indicated the maximum Se/Zn doses. Several-fold higher contents of Se and Zn in soybean straw compared to spiked soil suggest its possible use as Se/Zn-rich soil amendment in accordance with the circular economy goals. These novel findings may significantly contribute to human health improvement in Se and Zn deficient regions.


Assuntos
Solo , Soja , Biofortificação , Humanos , Estudos Prospectivos , Zinco/análise
4.
Urologiia ; (4): 157-164, 2020 Sep.
Artigo em Russo | MEDLINE | ID: mdl-32897031

RESUMO

The causes, some pathogenetic mechanisms and possibilities for correcting the decrease in male reproductive potential in Russia are discussed in the lecture. Particular attention is paid to oxidative stress as one of the main causes for subfertility and male infertility, as well as the role of trace elements (zinc, selenium) and antioxidants (vitamins A, E and C) in the pathogenesis of male infertility and opportunities for the correction of fertility issues. Some aspects of COVID-19 influence on the problems of reproductive medicine, andrology and urology are highlighted.


Assuntos
Antioxidantes , Infertilidade Masculina/fisiopatologia , Estresse Oxidativo , Oligoelementos , Betacoronavirus , Infecções por Coronavirus/complicações , Humanos , Infertilidade Masculina/virologia , Masculino , Pandemias , Pneumonia Viral/complicações , Reprodução , Federação Russa , Selênio , Zinco
5.
Water Sci Technol ; 81(12): 2522-2532, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32857740

RESUMO

Layered double hydroxides (LDH) with highly flexible and adjustable chemical composition and physical properties have attracted tremendous attention in recent years. A series of LDH with different M (Mg, Zn, Mn)-Fe molar ratios were synthesized by the double titration co-precipitation method. The effect of the factors, including M (Mg, Zn, Mn) : Fe molar ratio, pH, and M-Fe LDH dosage, on the ability of the prepared M-Fe LDH to remove cationic methylene blue (MB) dye from aqueous solution were investigated. Results indicated that the removal efficiency of MB (10 mg/L) was the best at the M (Mg, Zn, Mn): Fe molar ratio of 3:1 by using 2.0 g/L of M-Fe LDH at pH 6.0 under 298.15 K. Mg-Fe LDH had the highest removal performance (71.94 mg/g at 298.15 K) for MB compared to those of the Zn-Fe and Mn-Fe LDH. Zn-Fe LDH with the smallest activation energy resulted in the fastest adsorption rate of MB. The pseudo-second-order model and Langmuir adsorption isotherm were also successfully applied to fit the theory of M-Fe LDH for removal of MB.


Assuntos
Azul de Metileno , Poluentes Químicos da Água , Adsorção , Hidróxidos , Água , Zinco
6.
J Med Life ; 13(2): 138-143, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32742504

RESUMO

Treatment with anticancer drugs such as cyclophosphamide can harm the male reproductive system. Vitamin C and zinc are micronutrients with antioxidant activity and are the essential components of semen. Therefore, this study aimed to evaluate whether cyclophosphamide-exposed mice can recover from fertility with vitamin C and zinc therapy. In this experimental study, fifty male mice were divided into five groups. Groups 1-4 received cyclophosphamide (100 mg/kg, once a week for eight weeks). Also, group 2 received zinc (200 mg/kg), group 3 received vitamin C (300 mg/kg), group 4 received zinc and vitamin C (200 mg/kg and 300 mg/kg, respectively), five times per week for eight weeks, and group 5 received normal saline once a week and water five days a week for eight weeks. The data collected were statistically analyzed using SPSS 22. Results showed a significant increase in mount latency and a significant decrease in the number of sperms in the cyclophosphamide group compared to the control group. However, mount latency has been significantly decreased in mice treated with cyclophosphamide plus zinc compared to the cyclophosphamide group. The study also showed that the sperm count in the group that received cyclophosphamide and zinc had been increased compared to the cyclophosphamide group; the other treatments have decreased mount latency and increased the sperm count compared to the group treated with cyclophosphamide but not significantly. The Tubule Differentiation Index showed an increase in the cyclophosphamide-Zinc-Vitamin C group in comparison with the cyclophosphamide group. The current study showed that zinc could improve cyclophosphamide-induced toxicity of the reproductive system in male mice.


Assuntos
Antineoplásicos/efeitos adversos , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Substâncias Protetoras/farmacologia , Reprodução/efeitos dos fármacos , Zinco/farmacologia , Animais , Ácido Ascórbico/administração & dosagem , Ciclofosfamida/efeitos adversos , Hormônios/metabolismo , Humanos , Masculino , Camundongos , Comportamento Sexual Animal/efeitos dos fármacos , Contagem de Espermatozoides , Motilidade Espermática/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos
7.
PLoS Biol ; 18(7): e3000811, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32735558

RESUMO

One of the earliest and most prevalent barriers to successful reproduction is polyspermy, or fertilization of an egg by multiple sperm. To prevent these supernumerary fertilizations, eggs have evolved multiple mechanisms. It has recently been proposed that zinc released by mammalian eggs at fertilization may block additional sperm from entering. Here, we demonstrate that eggs from amphibia and teleost fish also release zinc. Using Xenopus laevis as a model, we document that zinc reversibly blocks fertilization. Finally, we demonstrate that extracellular zinc similarly disrupts early embryonic development in eggs from diverse phyla, including Cnidaria, Echinodermata, and Chordata. Our study reveals that a fundamental strategy protecting human eggs from fertilization by multiple sperm may have evolved more than 650 million years ago.


Assuntos
Fertilização , Oócitos/metabolismo , Zinco/metabolismo , Ambystoma mexicanum , Animais , Feminino , Hidrozoários , Masculino , Strongylocentrotus purpuratus , Xenopus laevis , Peixe-Zebra
8.
Environ Pollut ; 265(Pt B): 115084, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806463

RESUMO

The effects of the continuous accumulation of Zinc (Zn) on the fate of antibiotic resistance genes (ARGs) in constructed wetland-microbial fuel cells (CW-MFCs) remain unclear. In this study, the impacts of Zn addition and a circuit mode on antibiotic removal, occurrence of ARGs, the bacterial community, and bacterial functions were investigated in three groups of CW-MFCs. The results showed that continuous Zn exposure enriched the target ARGs during the initial stage, while excessive Zn accumulation decreased antibiotic removal and the abundance of ARGs. A principal component analysis demonstrated that ARGs and the bacterial community distribution characteristics were significantly impacted by the mass accumulation of antibiotics and Zn, as well as the circuit mode. A redundancy analysis, partial least squares path modeling, and Procrustes analysis revealed that the accumulation of antibiotics and Zn, the composition of the bacterial community, the circuit mode, and the abundance of intI associated with horizontal gene transfer jointly contributed to the distributions of ARGs in the electrodes and effluent. Moreover, continuous exposure to Zn decreased the bacterial diversity and changed the composition and function of the bacterial community predicted using PICRUSt tool. The co-occurrence of ARGs, their potential hosts and bacterial functions were further revealed using a network analysis. A variation partition analysis also showed that the accumulation of target pollutants and the circuit mode had a significant impact on the bacterial community composition and functions. Therefore, the interaction among ARGs, the bacterial community, bacterial functions, and pollutant accumulations in the CW-MFC was complex. This study provides useful implications for the application of CW-MFCs for the treatment of wastewater contaminated with antibiotics and heavy metals.


Assuntos
Fontes de Energia Bioelétrica , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Genes Bacterianos/efeitos dos fármacos , Áreas Alagadas , Zinco
9.
J Environ Sci (China) ; 96: 117-126, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32819686

RESUMO

Sediments in Lake Izabal, Guatemala, contain substantial lead (Pb), zinc (Zn), and nickel (Ni). The lack of historical data for heavy metal concentrations in the sediments makes it difficult to determine the sources or evaluate whether inputs of metals to the lake have changed through time. We measured the relative abundances and concentrations of Pb, Zn, and Ni by X-Ray Fluorescence core scanning and by Inductively Coupled Plasma Optical Emission Spectrometry in three sediment cores to explore stratigraphic distributions of metals in the lake deposits. High amounts of Pb and Zn in the core taken near the Polochic Delta suggest that galena and sphalerite mining increased Pb and Zn delivery to Lake Izabal between ~1945 and 1965 CE. An up-core Ni increase in the core taken near a different mine on the north shore of Lake Izabal suggests that recent nickel mining operations led to an increase in Ni concentrations in the local sediments, but amounts in the other cores indicate that Ni is not widely distributed throughout the lake. Sediment cores from Lake Izabal are reliable recorders of heavy metal input to the lake, and were measured to establish background metal levels, which would otherwise be unavailable. Concentrations of Pb, Zn, and Ni in older, pre-20th-century Lake Izabal sediments reflect input from natural erosion of bedrock. Our results provide previously unavailable estimates of background metal concentrations in Lake Izabal before the onset of mining. These results are necessary for future monitoring related to mining contamination of the lake ecosystem.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Guatemala , Lagos , Chumbo , Níquel , Zinco
10.
Nutrients ; 12(8)2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32784601

RESUMO

OBJECTIVES: The novel coronavirus infection (COVID-19) conveys a serious threat globally to health and economy because of a lack of vaccines and specific treatments. A common factor for conditions that predispose for serious progress is a low-grade inflammation, e.g., as seen in metabolic syndrome, diabetes, and heart failure, to which micronutrient deficiencies may contribute. The aim of the present article was to explore the usefulness of early micronutrient intervention, with focus on zinc, selenium, and vitamin D, to relieve escalation of COVID-19. METHODS: We conducted an online search for articles published in the period 2010-2020 on zinc, selenium, and vitamin D, and corona and related virus infections. RESULTS: There were a few studies providing direct evidence on associations between zinc, selenium, and vitamin D, and COVID-19. Adequate supply of zinc, selenium, and vitamin D is essential for resistance to other viral infections, immune function, and reduced inflammation. Hence, it is suggested that nutrition intervention securing an adequate status might protect against the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome - coronavirus-2) and mitigate the course of COVID-19. CONCLUSION: We recommended initiation of adequate supplementation in high-risk areas and/or soon after the time of suspected infection with SARS-CoV-2. Subjects in high-risk groups should have high priority as regards this nutritive adjuvant therapy, which should be started prior to administration of specific and supportive medical measures.


Assuntos
Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , Micronutrientes/uso terapêutico , Estado Nutricional , Pneumonia Viral/tratamento farmacológico , Selênio/uso terapêutico , Vitamina D/uso terapêutico , Zinco/uso terapêutico , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Deficiências Nutricionais/complicações , Progressão da Doença , Feminino , Humanos , Inflamação/prevenção & controle , Masculino , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/virologia
11.
Sci Total Environ ; 737: 140245, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783848

RESUMO

Zinc (Zn) fertilizer application can certainly improve the production and nutritional quality of cereal crops. However, Zn accumulation in the soil may lead to some deleterious environmental impacts in agroecosystems. The effects of long-term Zn application on soil microbial properties remain unclear, but it is imperative to understand such effects. In this study, we collected soil samples from a nine-year field experiment in a wheat-maize system that continuously received Zn applied at various rates (0, 2.3, 5.7, 11.4, 22.7 and 34.1 kg ha-1) to evaluate the soil enzymes, microbial biomass and microbial community structure. The results showed that Zn application at the rate of 5.7 kg ha-1 significantly increased the activities of urease, invertase, alkaline phosphatase and catalase in the soil, while the rate of 34.1 kg ha-1 significantly decreased the evaluated enzyme activities. The microbial biomass carbon (C) and nitrogen (N) were not affected by Zn application rates, although an increase in the microbial biomass C was observed in the 11.4 kg ha-1 treatment. Moreover, the alpha diversity of the bacterial and fungal communities did not vary among the nil Zn, optimal Zn (5.7 kg ha-1) and excess Zn (34.1 kg ha-1) treatments. However, the bacterial communities in the soil receiving the optimal and excess Zn application rates were slightly changed. Compared to the nil Zn treatment, the other Zn application rates increased the relative abundances of the Rhodospirillales, Gaiellales and Frankiales orders and decreased the abundance of the Latescibacteria phylum. The redundancy analysis further indicated that the soil bacterial community composition significantly correlated with the concentrations of soil DTPA-Zn and total Zn. These results highlight the importance of optimal Zn application in achieving high production and high grain quality while concurrently promoting soil microbial activity, improving the bacterial community and further maintaining the sustainability of the agroecological environment.


Assuntos
Microbiota , Solo , Biomassa , Fertilizantes , Nitrogênio/análise , Microbiologia do Solo , Zinco
12.
Appl Microbiol Biotechnol ; 104(19): 8089-8104, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32813065

RESUMO

Interspecies transmissions of viruses between animals and humans may result in unpredictable pathogenic potential and new transmissible diseases. This mechanism has recently been exemplified by the discovery of new pathogenic viruses, such as the novel severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) pandemic, Middle-East respiratory syndrome-coronavirus epidemic in Saudi Arabia, and the deadly outbreak of Ebola in West Africa. The. SARS-CoV-2 causes coronavirus disease-19 (COVID-19), which is having a massive global impact in terms of economic disruption, and, above all, human health. The disease is characterized by dry cough, fever, fatigue, myalgia, and dyspnea. Other symptoms include headache, sore throat, rhinorrhea, and gastrointestinal disorders. Pneumonia appears to be the most common and severe manifestation of the infection. Currently, there is no vaccine or specific drug for COVID-19. Further, the development of new antiviral requires a considerable length of time and effort for drug design and validation. Therefore, repurposing the use of natural compounds can provide alternatives and can support therapy against COVID-19. In this review, we comprehensively discuss the prophylactic and supportive therapeutic role of probiotics for the management of COVID-19. In addition, the unique role of probiotics to modulate the gut microbe and assert gut homeostasis and production of interferon as an antiviral mechanism is described. Further, the regulatory role of probiotics on gut-lung axis and mucosal immune system for the potential antiviral mechanisms is reviewed and discussed.Key points• Gut microbiota role in antiviral diseases• Factors influencing the antiviral mechanism• Probiotics and Covid-19.


Assuntos
Betacoronavirus/fisiologia , Infecções por Coronavirus/terapia , Pneumonia Viral/terapia , Probióticos/uso terapêutico , Animais , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Trato Gastrointestinal/microbiologia , Humanos , Imunidade nas Mucosas , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/virologia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão , Probióticos/metabolismo , Infecções Respiratórias/microbiologia , Viroses/prevenção & controle , Viroses/terapia , Viroses/transmissão , Vitamina D/fisiologia , Zinco/metabolismo
14.
Front Immunol ; 11: 1712, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32754164

RESUMO

During the current corona pandemic, new therapeutic options against this viral disease are urgently desired. Due to the rapid spread and immense number of affected individuals worldwide, cost-effective, globally available, and safe options with minimal side effects and simple application are extremely warranted. This review will therefore discuss the potential of zinc as preventive and therapeutic agent alone or in combination with other strategies, as zinc meets all the above described criteria. While a variety of data on the association of the individual zinc status with viral and respiratory tract infections are available, study evidence regarding COVID-19 is so far missing but can be assumed as was indicated by others and is detailed in this perspective, focusing on re-balancing of the immune response by zinc supplementation. Especially, the role of zinc in viral-induced vascular complications has barely been discussed, so far. Interestingly, most of the risk groups described for COVID-19 are at the same time groups that were associated with zinc deficiency. As zinc is essential to preserve natural tissue barriers such as the respiratory epithelium, preventing pathogen entry, for a balanced function of the immune system and the redox system, zinc deficiency can probably be added to the factors predisposing individuals to infection and detrimental progression of COVID-19. Finally, due to its direct antiviral properties, it can be assumed that zinc administration is beneficial for most of the population, especially those with suboptimal zinc status.


Assuntos
Antivirais/imunologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Suplementos Nutricionais , Pandemias/prevenção & controle , Pneumonia Viral/imunologia , Pneumonia Viral/prevenção & controle , Zinco/imunologia , Animais , Antivirais/farmacologia , Antivirais/uso terapêutico , Cílios/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Homeostase/imunologia , Humanos , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Mucosa Respiratória/imunologia , Internalização do Vírus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Zinco/deficiência , Zinco/farmacologia , Zinco/uso terapêutico
15.
Sci Total Environ ; 738: 140311, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32806385

RESUMO

Trace element concentrations in the rhizosphere were quantified to better understand why soil liming often fails to reduce cadmium (Cd) uptake by plants. Maize seedlings were grown on a soil with natural background levels of Cd and zinc (Zn). Soil liming increased soil pH from 4.9 to 6.5 and lowered the soil solution free ion activities by factor 7 (Cd) and 9 (Zn). In contrast, shoot Cd concentrations were unaffected by liming while shoot Zn concentrations were lowered by factor 1.9. Mapping of labile soil trace elements using diffusive gradients in thin films (DGT) in combination with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) revealed an almost complete depletion of Cd in the rhizosphere in all soil treatments, showing that Cd uptake is controlled by diffusion. The flux of Cd from soil to the DGT, with direct contact between the soil and the binding gel, was unaffected by liming whereas it decreased by factor 3 for Zn, closely mimicking the contrasting effects of liming on Cd and Zn bioavailability. This evidence, combined with additional flux data of freshly spiked Cd and Zn isotopes in soil and with modelling, suggests that the diffusive transport of Cd in unsaturated soil is more strongly controlled by the labile adsorbed metal concentration than by its concentration in solution. This is less the case for Zn because of its inherently slower desorption compared to Cd.


Assuntos
Poluentes do Solo/análise , Oligoelementos , Cádmio/análise , Rizosfera , Solo , Zea mays , Zinco/análise
16.
Wiad Lek ; 73(7): 1434-1437, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32759433

RESUMO

OBJECTIVE: The aim:to study the content of trace elements (Fe, Cu, Zn, Co, Cr, Ni, Pb) in the placenta of pregnant healthy women and with signs of intrauterine infection of the fetus, features of transplacental transmission of infectious process from mother to fetus and to investigate the role of the placenta in trace element supply of the fetus. PATIENTS AND METHODS: Materials and methods. 43 pregnant women between the aged 16 to 40 years were monitored, including 12 with physiological pregnancy (group 1) and 31 with signs of STI (group 2). All pregnant women underwent standard comprehensive examination, evaluation of fetal cardiac output and non-stress testing using cardio-toсography (CTG) in the third trimester. The group of pregnant women with signs of fetal ulcers included women whose pregnancy was complicated by chronic fetoplacental dysfunction (FPD), infectious lesions of the fetoplacental complex, which were diagnosed on the basis of ultrasound signs of placenta, syndrome of infectious and surrounding infections. RESULTS: Results:The content of essential trace elements in the placenta of the main group was significantly lower than in the placenta of the control group. There was a decrease in the concentration of iron by 32%, zinc - by 46%, nickel - by 44%, copper more than tripled, chromium - 4 times. Deficiency of essential trace elements (iron, zinc, copper, chromium, nickel) and elevated lead content in the placenta leads to the formation of conditions for the development of placental dysfunction, the progression of which leads to fetal distress, developmental delay syndrome and antenatal fetal death. CONCLUSION: Conclusions:1. One of the links in the pathogenesis of intrauterine infection in the fetus is the imbalance of essential trace elements in the system «mother - placenta - fetus¼. 2. Pregnant women with signs of intrauterine infection are characterized by a deficiency of serum Fe, Cu, Zn, Ni and an increased content of Pb, Cr and Co compared with pregnant women with physiological pregnancy. 3. Umbilical cord blood of women with evidence of fetal fetal infection also has a reduced content of iron, copper, zinc and high levels of lead, cobalt and chromium. 4. Disruption of placental function in intrauterine infection of the fetus is caused by reduced content of iron, zinc, copper, nickel and lead accumulation.


Assuntos
Doenças Transmissíveis , Adolescente , Adulto , Feminino , Feto , Humanos , Placenta , Gravidez , Oligoelementos , Adulto Jovem , Zinco
17.
Mar Pollut Bull ; 158: 111094, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753165

RESUMO

Concentrations of Fe, Mn, Zn, and Cu in the muscle, lung, liver, and kidney tissues of 49 cetaceans, including 11 Kogia sima (Ks), 10 Lagenodelphis hosei (Lh), 14 Grampus griseus (Gg), and 14 Stenella attenuata (Sa) from 1994 to 2012 in Taiwan were measured. Ks exhibited the highest Fe, and the lowest Zn, Cu and Mn tissue concentrations. The Kogiid and Delphinid groups were significantly categorized by nMDS analysis. Fe muscle concentrations were found to be positively correlated with Ks, Lh, and Gg but not Sa body length. The different levels of Zn-, Cu-, and Mn- tissue concentrations of the two families were due to their different SOD systems. Their calves contained higher Cu liver concentrations. The four essential elements in cetaceans regulate homeostasis to meet their eco-physiological demand. The baseline levels for these four elements in these four tissues in the Delphinid group are defined.


Assuntos
Golfinhos , Oligoelementos/análise , Animais , Bovinos , Fígado/química , Taiwan , Baleias , Zinco/análise
18.
Mar Pollut Bull ; 158: 111433, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753216

RESUMO

Sacrificial anodes are attached to the hulls of boats and marine structures to prevent corrosion. Their use inevitably leads to release of zinc as well as impurities in the zinc alloy such as cadmium to the saline environment. Risk assessments and source apportionment exercises require accurate assessments of the potential loads of chemicals into the environment. This research has surveyed a wide variety of zinc anodes for their composition to compare against a reported industry standard as well as using differing methodologies to determine the dissolution rate of zinc and cadmium from anodes. A zinc dissolution rate of 477 g/yr/kg of anode is proposed. Although most anodes tested had concentrations of cadmium within the prescribed limits set by the reported standard, calculated leaching rates from laboratory dissolution experiments suggested as much as 400 g per year of cadmium could leach from zinc anodes used on leisure vessels within UK waters.


Assuntos
Cádmio , Zinco , Eletrodos , Atividades de Lazer , Águas Salinas
19.
Environ Sci Process Impacts ; 22(8): 1731-1742, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32672306

RESUMO

A study on the sequestering ability between arsenate, AsO43-, and Cu2+ and Zn2+ in aqueous solution is reported. The results of the elaboration of potentiometric data include only species with 1 : 1 metal to ligand ratio for Cu2+-arsenate system, namely CuLH2, CuLH, CuL, and CuLOH (L = AsO43-). For the Zn2+-arsenate system, a speciation model with only two species with both 1 : 1 and 1 : 2 metal to ligand ratios was obtained, namely ML and ML2. Spectrophotometric titrations were also employed in the study of the Cu2+-AsO43- system, and the results of the analysis of experimental data fully confirmed potentiometric ones. The potentiometric titrations were performed under different conditions of temperature (288.15 ≤ T/K ≤ 310.15, at I = 0.15 mol L-1) and ionic strength (0.15 ≤ I/mol L-1 ≤ 1 in NaCl). The dependence of formation constants of the complex species on ionic strength and temperature was also evaluated, as well as the enthalpy and entropy change values were obtained. Laser desorption mass spectrometry (LD MS) and tandem mass spectrometry (MS/MS) were exploited to confirm Cu2+-AsO43- and Zn2+-AsO43- complex formation and to determine both their composition and structural characteristics. Simulation of speciation profiles under natural water conditions was performed. The sequestering ability of arsenate towards Cu2+ and Zn2+ was quantified under different conditions of pH, temperature and ionic strength, typical of several natural waters. Examples of arsenate distribution under seawater and freshwater conditions were reported.


Assuntos
Arseniatos , Espectrometria de Massas em Tandem , Arseniatos/química , Concentração Osmolar , Termodinâmica , Zinco
20.
Ecotoxicol Environ Saf ; 202: 110893, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615495

RESUMO

Leaching of the hazardous electric arc furnace (EAF) dust containing mainly zinc ferrite and zinc oxide, accompanied by minor concentrations of arsenic compounds, was investigated using sulfuric acid. In order to reach the maximum recovery of zinc, the leaching solution was adjusted to recover both iron and zinc at their maximum possible values. To obtain a high recovery value of zinc and iron, analyzed by AAS, the optimum leaching condition was found to be the temperature of 90 °C, the sulfuric acid concentration of 3 M, the particle size of 75 µm, the S/L ratio of 1:10 g/mL and the leaching time of 2 h. The percentages of the zinc and iron recovery under the optimum condition were ca. 98.6% and 99.1% respectively, which were verified by a confirmation test and were very close to the predicted values of 100% based on the optimized model, obtained through the software. From the thermodynamics' point of view, it has been found that Zn2+ is the predominant species (90%) under the leaching condition applied. Moreover, the predominant species of iron are FeSO4+, FeHSO42+, Fe(SO4)2- and Fe3+ in the magnitudes of 65.8%, 25.6%, 4.4% and 4.0%, respectively. According to the kinetic results, the controlling step in the leaching was the chemical reaction at the most of the operating temperatures and times. In order to purify the zinc solution for electrowinning, iron and arsenic were removed through the jarosite formation process as confirmed by the XRD results. The speciation of arsenic in the precipitated jarosite was explored by XPS. Finally, the low concentrations of arsenic (less than 0.1 ppm) and iron (less than 50 ppm) were determined by the ICP analysis.


Assuntos
Compostos Férricos/química , Metalurgia/métodos , Reciclagem , Sulfatos/química , Zinco/análise , Poeira/análise , Eletricidade , Ferro/química , Tamanho da Partícula , Ácidos Sulfúricos , Temperatura , Óxido de Zinco
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