Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40.453
Filtrar
1.
Rev Environ Contam Toxicol ; 249: 1-27, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30725190

RESUMO

Metals are major abiotic stressors of many organisms, but their toxicity in plants is not as studied as in microorganisms and animals. Likewise, research in plant responses to metal contamination is sketchy. Candidate genes associated with metal resistance in plants have been recently discovered and characterized. Some mechanisms of plant adaptation to metal stressors have been now decrypted. New knowledge on microbial reaction to metal contamination and the relationship between bacterial, archaeal, and fungal resistance to metals has broadened our understanding of metal homeostasis in living organisms. Recent reviews on metal toxicity and resistance mechanisms focused only on the role of transcriptomics, proteomics, metabolomics, and ionomics. This review is a critical analysis of key findings on physiological and genetic processes in plants and microorganisms in responses to soil metal contaminations.


Assuntos
Adaptação Fisiológica/fisiologia , Ecossistema , Metais/toxicidade , Plantas , Microbiologia do Solo , Poluentes do Solo/toxicidade , Animais , Fungos , Metais Pesados , Solo
2.
Rev Environ Contam Toxicol ; 248: 111-189, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30671689

RESUMO

Metal-rich sediments have the potential to impair life in freshwater streams and rivers and, thereby, to inhibit recovery of ecological conditions after any remediation of mine water discharges. Sediments remain metal-rich over long time periods and have long-term potential ecotoxicological interactions with local biota, unless the sediments themselves are physically removed or replaced by less metal-rich sediment. Laboratory-derived environmental quality standards are difficult to apply to the field situation, as many complicating factors exist in the real world. Therefore, there is a strong case to consider other, field-relevant, measures of toxic effects as alternatives to laboratory-derived standards and to seek better biological tools to detect, diagnose and ideally predict community-level ecotoxicological impairment. Hence, this review concentrated on field measures of toxic effects of metal-rich sediment in freshwater streams, with less emphasis on laboratory-based toxicity testing approaches. To this end, this review provides an overview of the impact of metal-rich sediments on freshwater stream life, focusing on biological impacts linked to metal contamination.


Assuntos
Monitoramento Ambiental , Metais/análise , Mineração , Rios , Poluentes Químicos da Água/análise , Água Doce , Sedimentos Geológicos/química
3.
J Environ Sci (China) ; 85: 74-81, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471033

RESUMO

A column leaching experiment was used to investigate the efficacy of amendments on their ability to remove alkaline anions and metal ions from bauxite residue leachates. Treatments included, simulated acid rain (AR), phosphogypsum + vermicompost (PVC), phosphogypsum + vermicompost + simulated acid rain (PVA), and biosolids + microorganisms (BSM) together with controls (CK). Results indicated that amendment could effectively reduce the leachate pH and EC values, neutralize OH-, CO32-, HCO3-, and water soluble alkali, and suppress arsenic (As) content. Correlation analysis revealed significant linear correlations with pH and concentrations of OH-, CO32-, HCO3-, water-soluble alkali, and metal ions. BSM treatment showed optimum results with neutralizing anions (OH-, CO32-, and HCO3-), water soluble alkali, and removal of metal ions (Al, As, B, Mo, V, and Na), which was attributed to neutralization from the generation of small molecular organic acids and organic matter during microbial metabolism. BSM treatment reduced alkaline anions and metal ions based on neutralization reactions in bauxite residue leachate, which reduced the potential pollution effects from leachates on the soil surrounding bauxite residue disposal areas.


Assuntos
Óxido de Alumínio/química , Metais/química , Modelos Químicos , Poluentes do Solo/química , Ânions
4.
J Biol Regul Homeost Agents ; 33(3 Suppl. 1): 43-50, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31538449

RESUMO

Customization of post-and-cores using computer-aided-design and computer-aided-manufacturing (CAD-CAM) requires the scanning of a pattern and the subsequent digital design. This case report describes the production of a CAD-CAM customized post-and-core designed from an intraoral scan and milled from a metal block. The use of an intraoral scanner (IOS) for post-endodontic rehabilitation could lead to a faster and more efficient CAD-CAM customized post-and-core realization. The use of a high resistance material such as metal is paramount in cases with high loss of coronal structure. The patient has been treated with bisphosphonate (BP) for years. The risk of osteonecrosis of the jaw after extraction was high.


Assuntos
Projeto Auxiliado por Computador , Implantes Dentários , Fluxo de Trabalho , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos , Implantação Dentária Endo-Óssea Endodôntica , Difosfonatos/efeitos adversos , Difosfonatos/uso terapêutico , Humanos , Metais
5.
Ecotoxicol Environ Saf ; 182: 109458, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31398784

RESUMO

Acid mine drainage (AMD) is a significant contributor of metal pollution leading to ecosystem damage. Bioindicator organisms such as intertidal brown macroalgae have an important role in quantifying the risks of metal bioaccumulation in coastal locations exposed to AMD contamination. Measurement of As, Cd, Cu, Fe, Pb, and Zn accumulation was performed in Fucus serratus, Fucus vesiculosus and Ascophyllum nodosum sampled from two marine locations near to an abandoned Cu mine in Anglesey, Wales, UK. Transect samples were taken from a coastal location (Amlwch) that has seen a substantial increase in AMD contamination over 15 years, in comparison to a nearby estuarine location (Dulas Estuary leading to Dulas Bay) with a historic legacy of pollution. These were compared with samples from the same sites taken 30 years earlier. Some of the Dulas macroalgae samples had Cd, Cu and Zn concentrations that were above background but in general indicated a non-polluted estuary in comparison to substantial pollution over previous decades. In contrast, Fucus samples collected from directly below an AMD outflow at Amlwch showed extremely elevated metal bioaccumulation (>250 mg Fe g-1, >6 mg Cu g-1, >2 mg Zn g-1, >190 µg As g-1) and evidence of macroalgae toxicity, indicating severe pollution at this site. However, the pollution dispersed within 200 m of the outflow source. This study has demonstrated the efficiency of three brown macroalgae species as indicators for metal bioavailability at high spatial resolution and over time.


Assuntos
Monitoramento Ambiental/métodos , Recuperação e Remediação Ambiental , Metais/análise , Mineração , Poluentes Químicos da Água/análise , Biomarcadores Ambientais , Poluição Ambiental , Metais Pesados/análise , Alga Marinha , País de Gales
6.
Bioresour Technol ; 293: 122027, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31454735

RESUMO

Thermal conversion is a promising approach for the disposal of phytoremediation biowastes. The thermal characteristics of potherb mustard biowaste contaminated by potentially toxic metals were studied in this work. Thermogravimetric (TG) and derivative thermogravimetric (DTG) analyses of four feedstocks with different Cd/Zn content were conducted in an inert environment. Evolved gases were identified online by mass spectrometry (MS) coupled with TG. The TG-DTG profiles of the four feedstocks presented similar decomposition stages, whereas the samples with low Cd/Zn had a faster degradation rate, suggesting that the presence of Cd/Zn had little effect on thermal decomposition mechanism. The maximum evolution of H2 and CH4 occurred at 500-650 °C, while CO was released at a low temperature. PTMs could catalyze the H2 production during the pyrolysis of biowaste. This investigation revealed the effects of different Cd/Zn contents on thermal conversion, providing a practical reference for the thermal treatment of phytoremediation biowastes.


Assuntos
Gases , Mostardeira , Biodegradação Ambiental , Espectrometria de Massas , Metais , Termogravimetria
7.
Waste Manag ; 96: 175-180, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376962

RESUMO

Recycling resources from millions of tons of e-wastes are a global challenge. E-wastes is complex and contains both toxic organics and valuable metals. Therefore, the technologies for e-wastes recycling are totally different from those used for mineral separation. Current technologies for e-wastes tend to focus on recycling materials with high economic value and ignore components that cannot be recycled or have low reuse value. As a result, some secondary pollution problems inevitably occur due to the recycling process. Based on these problems, we summarize the universal characteristics of e-wastes and explore new approaches to achieve complete resource recycling of e-wastes with minimum secondary waste generation. A concept of element recycling is proposed to achieve complete resource recycling of e-wastes in the study. We can use the properties of the elements in different types of e-wastes to achieve e-wastes recycling, i.e., recycle of elements in e-wastes. Under the guidance of element recycling, various e-wastes types have common connections. If element recycling in e-wastes is realized, all components in e-wastes can be fully recycled without/with minimal production of secondary waste. The two case studies are discussed to clarify the concept and principle of element recycling. This study explores the recycling of e-wastes from a new perspective-element recycling in e-wastes. The concept of element recycling is significant for resource recycling from e-wastes.


Assuntos
Resíduo Eletrônico , Metais , Reciclagem
8.
Chem Commun (Camb) ; 55(70): 10444-10447, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31410430

RESUMO

A new series of 2D catalytic materials whose inorganic surfaces are fully covered with pre-designed "promoter" groups are reported. One of them showed excellent biomimetic catalytic activity and provided the lowest detection limit to glucose among the reported 2D materials and their composite materials.


Assuntos
Biomimética , Calcogênios/química , Metais/química , Catálise , Limite de Detecção , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica , Difração de Pó
9.
Waste Manag ; 98: 21-28, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421486

RESUMO

The low bioleaching efficiency of Acidithiobacillus ferrooxidans results in its sparse industrial application for metal extraction from waste printed circuit boards (WPCBs). To improve the bioleaching efficiency of Acidithiobacillus ferrooxidans, we propose the use of mechanical activation to dispose WPCBs prior to performing bioleaching. Response surface methodology (RSM), scanning electron microscope- energy dispersive spectrometer (SEM-EDS), and laser particle size analyzer (LPSA) were used to optimize and analyze the mechanical activation process, respectively. The optimal conditions for mechanical activation was a milling time of 2 h, milling speed of 340 r min-1, and ball material ratio (w/w) of 10/1; the bioleaching rates of Cu, Ni, and Zn were 94.33%, 90.69%, and 90.78%, respectively. The bioleaching rates of Cu, Ni, and Zn were 74.75%, 70.46%, and 71.05%, respectively, without mechanical activation pretreatment. SEM-EDS and LPSA analyses indicated that mechanical activation could lead to a smaller particle size and expose wrapped metals, thus improving the bioleaching efficiency oyf tyhe metals inside the WPCBs. The electrode potential of the metals was likely changed by the mechanical activation, resulting in an improvement of their bioleaching efficiency. Additionally, the bioleaching rates of Pb, Cr, and Cd after mechanical activation pretreatment were 10.29%, 74.89%, and 54.12%, respectively. Contrastingly, the bioleaching rates of Pb, Cr, and Cd without mechanical activation pretreatment were 5.18%, 59.97%, and 37.12%, respectively. Thereinto, the precipitation of PbSO4 may result in a decrease of leached Pb. We propose a mechanical activation process for improving the bioleaching efficiency of metals from WPCBs.


Assuntos
Acidithiobacillus , Metais
11.
Bol. latinoam. Caribe plantas med. aromát ; 18(4): 378-391, jul. 2019. tab
Artigo em Inglês | LILACS | ID: biblio-1008176

RESUMO

The content of certain metals in 13 medicinal teas made from 16 plant species was measured by flame photometer and atomic absorption spectrometer with flame methods. The measurements were evaluated against metal intake levels recommended by health authorities. The results indicate that the medicinal teas tested, regularly consumed by inhabitants of the Urubueua de Fátima River Community, Abaetetuba-Para, Brazil, present no risk of poisoning people older than six months. However, decoctions of Mentha sp., Eleutherine bulbosa, Euterpe oleracea, Piper callosum and Hyptis mutabilis, mostly given to children, had Mn values potentially exceeding the recommended maximum intake for infants in the 0-6 months age group, in the quantities customarily administered. Consequently, studies are needed to assess bioavailability for safe human consumption. Results also showed the consumption of medicinal tea alone is not enough to supply an adult's daily metal requirements or treat deficiencies. Additionally, cures emphasized by interviewed Community members might be associated with the bioactivity of organic substances that the medicinal teas contain.


El contenido de algunos metales en 13 tés medicinales de las 16 especies consumidas por los habitantes de la comunidad del Río Urubueua de Fátima, Abaetetuba-Para, Brasil, se evaluó mediante un fotómetro de llama y un espectrómetro de absorción atómica con métodos de llama, y se comparó con los niveles recomendados por las agencias de la salud. Los tés medicinales evaluados no mostraron riesgo de intoxicación para las personas mayores de seis meses de edad, sino las decocciones de Mentha sp., Eleutherine bulbosa, Euterpe oleracea, Piper callosum y Hyptis mutabilis, en su mayoría dirigidos a la ingesta de niños, informaron valores de Mn superiores a la ingesta máxima recomendada para el grupo de infantes (0-6 meses), debido a que estos estudios son necesarios para evaluar la biodisponibilidad para un consumo humano seguro. Los resultados también mostraron que solo el consumo de té medicinal no es suficiente para satisfacer las necesidades diarias recomendadas de ingesta de minerales o para tratar las deficiencias. Además, los informes de curación, enfatizados por los habitantes, indican que la bioactividad observada podría estar asociada a sustancias orgánicas presentes en el té.


Assuntos
Plantas Medicinais/química , Extratos Vegetais/química , Chás Medicinais , Metais/análise , Valores de Referência , Brasil
12.
Zhonghua Bing Li Xue Za Zhi ; 48(7): 510-514, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31288304

RESUMO

Objective: To analyze the clinicopathological features of pseudotumor-like tissue around aseptic joint arthroplasty and aseptic lymphocytic vasculitis-associated lesions (ALVAL) scores. The characters of wear granules were observed. Methods: Total 122 cases were retrieved from the surgical pathology files between May 2015 and August 2018 in the department of pathology in Beijing Jishuitan Hospital, which included the knee joint arthroplasty (10 cases) and hip arthroplasty (112 cases). There were 62 females and 60 males. Patients' age ranged from 29 to 86 years (mean 56 years). The pseudotumor-like tissue around aseptic joint arthroplasty were stained with HE and analyzed by two ALVAL score systems. The characters of wear granules were observed by light microscope and polarized light. Results: The cohort included 62 females and 60 males. Patients' age ranged from 29 to 86 years (mean 56 years). Compbell-ALVAL system includes synovial lining,inflammatory infiltrate and tissue organization. The scores were: low (0-4): 18cases; moderate (5-8): 101 cases; high (9-10): 3 cases. Oxford-ALVAL system only evaluated the inflammatory infiltrate,and the scores were:0 grade:56 cases; 1 grade:51 cases; 2 grade: 12 cases; 3 grade:3 cases. Cases with high score in the Compbell-ALVAL system were concordant with the 3 grade of the Oxford-ALVAL system. Under light microscope,the metal particles were small black granules; the polyethylene fibers were needle-like and easily visible in polarized light. The polymethylmethacrylate showed clear spaces because of particle melting. Conclusions: The Compbell-ALVAL scoring system is based on the histologic analysis of pseudotumor-like tissue around aseptic joint arthroplasty, and the Oxford-ALVAL scoring systems is based on lymphocytic response. The wear particles could be differentiated by the features in the light microscope.


Assuntos
Artroplastia de Substituição , Artropatias/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Metais , Pessoa de Meia-Idade , Desenho de Prótese , Falha de Prótese
13.
Phys Chem Chem Phys ; 21(28): 15747-15759, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31276128

RESUMO

The catalytic cofactor of the most common form of nitrogenase contains seven irons and one molybdenum bound together by sulfide bonds. Surprisingly, a central carbide has been demonstrated by experiments. Another noteworthy structural component is a large homocitrate ligand. In recent theoretical studies it has been shown that the central carbide is needed as a place for the incoming protons that are necessary parts of a reduction process. It has also been shown that a role for the homocitrate ligand could be that it may be rotated to release one bond to molybdenum. In the present study, the carbide protonation steps are reinvestigated with similar results to those reported before. The actual activation of N2 in the E4 state is an extremely complicated process. It has been found experimentally that two hydrides should leave as H2, in a reductive elimination process, to allow N2 activation in E4 in an easily reversible step. It is here suggested that after H2 is released, it is necessary for the metal cofactor to get rid of one proton. This is achieved by protonating the homocitrate and then rotating it to release one of the bonds to Mo. After this rotation, N2 can bind. In the E5 step, the homocitrate is rotated back to its original position and remains that way until the end of the catalytic process. The N2 protonation steps are energetically easy. Since a protonated carbide has never been observed experimentally, it is necessary to also have a mechanism for deprotonating the carbon at the end of the catalytic cycles. Such a mechanism is suggested here.


Assuntos
Nitrogenase/metabolismo , Carbono/química , Coenzimas/química , Ativação Enzimática , Metais/química , Nitrogenase/química , Prótons
14.
J Agric Food Chem ; 67(31): 8527-8535, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31298526

RESUMO

l-Valine belongs to the branched-chain amino acids (BCAAs) and is an essential amino acid that is crucial for all living organisms. l-Valine is industrially produced by the nonpathogenic bacterium Corynebacterium glutamicum and is synthesized by the BCAA biosynthetic pathway. Ketol-acid reductoisomerase (KARI) is the second enzyme in the BCAA pathway and catalyzes the conversion of (S)-2-acetolactate into (R)-2,3-dihydroxy-isovalerate, or the conversion of (S)-2-aceto-2-hydroxybutyrate into (R)-2,3-dihydroxy-3-methylvalerate. To elucidate the enzymatic properties of KARI from C. glutamicum (CgKARI), we successfully produced CgKARI protein and determined its crystal structure in complex with NADP+ and two Mg2+ ions. Based on the complex structure, docking simulations, and site-directed mutagenesis experiments, we revealed that CgKARI belongs to Class I KARI and identified key residues involved in stabilization of the substrate, metal ions, and cofactor. Furthermore, we confirmed the difference in the binding of metal ions that depended on the conformational change.


Assuntos
Proteínas de Bactérias/química , Corynebacterium glutamicum/enzimologia , Cetol-Ácido Redutoisomerase/química , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Domínio Catalítico , Corynebacterium glutamicum/química , Corynebacterium glutamicum/genética , Cristalografia por Raios X , Cetol-Ácido Redutoisomerase/genética , Cetol-Ácido Redutoisomerase/metabolismo , Metais/química , Metais/metabolismo , Simulação de Acoplamento Molecular , NADP/química , NADP/metabolismo
15.
Environ Monit Assess ; 191(7): 476, 2019 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-31256265

RESUMO

Concentrations of arsenic, nickel and chromium in sediments of the nearshore Pilbara Region of Western Australia's mid -north coast have caused concerns to regulators issuing ocean disposal permits for many years. A meta-analysis of data from a large number of surveys, conducted in support of permit applications over many years and across hundreds of kilometres of coastline, shows that, when assessed as total metal concentrations, chromium and nickel occur routinely at concentrations above those recommended as screening triggers by national guidelines and arsenic more rarely. Arsenic was concentrated in surface sediments, consistent with an organic origin. Concentrations of nickel and chromium were higher in deeper sediment layers, consistent with a natural geological origin. However, sediment particle sizing was a major determinant of total metal concentrations of all three metals, and bioavailability was always much lower and within recommended guidelines. Past dredging activity for channels and berths in the large ports of the Pilbara has most likely led to an elevation of fine fractions of surface sediments within operating port areas, when compared to the undisturbed surrounding areas, and may also have increased the proportion of sediment from deeper substrates at the surface. Whilst total concentrations of chromium and nickel commonly exceed screening guidelines throughout the nearshore Pilbara Region, their bioavailability was low and these metals present a little threat to biota.


Assuntos
Sedimentos Geológicos/análise , Metais/análise , Poluentes Químicos da Água/análise , Arsênico/análise , Disponibilidade Biológica , Cromo/análise , Monitoramento Ambiental , Níquel/análise , Oceanos e Mares , Austrália Ocidental
16.
J Zoo Wildl Med ; 50(2): 503-507, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31260224

RESUMO

The clapper rail (Rallus crepitans) is native to salt marshes along the eastern United States. Populations are likely stable, but may be at risk due to the degradation of wetland habitat by contaminants. Contaminants can cause adverse effects in birds such as alteration of immune and reproductive function, and previous studies have used this species as a sentinel for estuarine health. Blood samples were collected from clapper rails in Florida and hematology counts, plasma biochemistry panels, and metal assessments using inductively coupled plasma-mass spectrometry were performed. Biochemical and hematology data were too limited to determine if contaminants were adversely affecting clapper rails in this study, but cadmium, lead, and zinc were increased for several birds. Although contaminant levels were not consistently elevated for all birds, additional research is needed to assess if clapper rails in this region are at risk of contaminant exposure due to increasing urbanization and development pressures.


Assuntos
Aves/sangue , Poluentes Ambientais/sangue , Testes Hematológicos/veterinária , Metais/sangue , Áreas Alagadas , Envelhecimento , Animais , Animais Selvagens , Monitoramento Ambiental , Poluentes Ambientais/química , Florida , Metais/química
17.
J Agric Food Chem ; 67(28): 7821-7831, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31260293

RESUMO

The mechanism of inhibition of advanced glycation end product (AGE) formation by protocatechuic acid and 3,4-dihydroxyphenylacetic acid (DHPA) has been studied using a widespread applied in vitro model system composed of bovine serum albumin (BSA) and supraphysiological glucose concentrations. Protocatechuic acid and DHPA inhibited the formation of Amadori compounds, fluorescent AGEs (IC50 = 62.1 ± 1.4 and 155.4 ± 1.1 µmol/L, respectively), and Nε-(carboxymethyl)lysine (IC50 = 535.3 ± 1.1 and 751.2 ± 1.0 µmol/L, respectively). BSA was pretreated with the two phenolic acids, and the formation of BSA-phenolic acid adducts was estimated by nanoflow liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry. Results showed that the tested phenolic acids bound key sites of glycation in BSA through a metal-catalyzed oxidative mechanism. The antiglycative activity mechanism involved the formation of BSA-phenolic acid adducts, and it is unlikely that this occurs in vivo. These results raise the problem to design in vitro models closer to physiological conditions to reach biologically sound conclusions.


Assuntos
Ácido 3,4-Di-Hidroxifenilacético/química , Hidroxibenzoatos/química , Lisina/química , Metais/química , Soroalbumina Bovina/química , Animais , Catálise , Bovinos , Cromatografia Líquida , Glicosilação , Oxirredução , Espectrometria de Massas por Ionização por Electrospray
19.
Int J Occup Environ Med ; 10(3): 152-154, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31325299
20.
Sci Total Environ ; 690: 867-877, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31302551

RESUMO

Fishery targeted species living in estuaries face multiple anthropogenic pressures including habitat contamination. However, trace metal concentrations in aquatic organisms can be highly variable, making it difficult to interpret accumulation responses. Understanding sources for metal accumulation in these organisms and their biokinetics is important for management of local fisheries and ensuring safety and quality of consumed seafood, particularly in urbanised areas. In this study, we exposed Australian sand clams, school prawns and sand whiting to a combination of cadmium (Cd), manganese (Mn) and zinc (Zn) radioisotopes 1) dissolved in seawater, 2) adsorbed to suspended sediment particles and 3) in radiolabelled food. Sand clams were sensitive to Cd, Mn and Zn uptake and accumulation from all sources because of their filter feeding physiology. Mean Cd and Zn assimilation efficiencies (AE) were higher in clams fed benthic diatoms (51, 43, 63% for Cd, Mn and Zn, respectively) than clams fed an algal flagellate species (22, 32, 33% for Cd, Mn and Zn, respectively). Metal uptake by prawns from seawater was low, whereas assimilation from diet was high (67, 59, 64% mean AEs from Cd, Mn and Zn, respectively). Sand whiting did not accumulate metals from seawater, even after concentrations were increased. Assimilation from diet (labelled prawns) was also low for sand whiting, particularly for Cd and Zn (11, 26, 14% mean AEs from Cd, Mn and Zn, respectively). These results may help explain the persistence of sand whiting in contaminated estuaries. Suspended sediment exposures showed that prawns and fish are less likely than clams to be negatively affected by disturbance events such as floods, which can bring metals into estuaries. The findings of this study have implications for fisheries management, both for protection and remediation of important habitats, and to ensure safe standards for seafood consumption by humans.


Assuntos
Organismos Aquáticos/metabolismo , Pesqueiros/estatística & dados numéricos , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Cádmio/metabolismo , Manganês/metabolismo , Zinco/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA