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1.
Rev Environ Contam Toxicol ; 248: 111-189, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-30671689

RESUMEN

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.


Asunto(s)
Monitoreo del Ambiente , Metales/análisis , Minería , Ríos , Contaminantes Químicos del Agua/análisis , Agua Dulce , Sedimentos Geológicos/química
2.
Environ Sci Technol ; 47(15): 8532-9, 2013 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-23802799

RESUMEN

Zinc oxide nanoparticles (ZnO NPs) are among the most commercialized engineered nanomaterials. Their biological impact in aquatic organisms has been associated with dissolution, but there is also evidence of nanospecific effects. In this study the waterborne uptake and efflux kinetics of isotopically labeled (68)ZnO NPs (7.8 ± 1.2 nm), in comparison to aqueous (68)Zn and (68)ZnO bulk particles (up to 2 µm), were determined for the estuarine snail Peringia ulvae following a 7 d exposure (nominally 20 µg (68)Zn L(-1)) and 28 d depuration. Detection of the (68)Zn label was achieved by high precision multiple-collector ICP-MS (MC-ICP-MS). Previous characterization in artificial estuarine water revealed that the NPs underwent initial aggregation and solubilized up to 60% within 1-2 days. Bulk and aqueous forms were significantly more bioavailable than (68)ZnO NPs (p < 0.05), but after correcting for dissolution, aqueous (0.074 L(-1) g(-1) d(-1)) and NP (0.070 L(-1) g(-1) d(-1)) uptake rate constants were highly comparable. The rate constant of loss for (68)Zn aqueous (0.012 ± 0.005 d(-1)) and (68)ZnO NPs (0.012 ± 0.007 d(-1)) were identical. These results strongly suggest that in this exposure scenario the bioaccumulation of Zn from ZnO NPs is primarily dependent upon solubility.


Asunto(s)
Estuarios , Isótopos/análisis , Caracoles/química , Óxido de Zinc/química , Animales , Solubilidad
3.
Environ Sci Technol ; 46(6): 3465-71, 2012 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-22372853

RESUMEN

The link between metal exposure and toxicity is complicated by numerous factors such as exposure route. Here, we exposed a marine fish (juvenile blackhead seabream Acanthopagrus schlegelii schlegelii) to copper either in a commercial fish diet or in seawater. Copper concentrations in intestine/liver were correlated linearly with influx rate, but appeared to be less influenced by uptake pathway (waterborne or dietary exposure). Influx rate best predicted Cu accumulation in the intestine and liver. However, despite being a good predictor of mortality within each pathway, influx rate was not a good predictor of mortality across both exposure pathways, as waterborne Cu caused considerably higher mortality than dietary Cu at a given influx rate. We show that the use of gill Cu accumulation irrespective of the exposure route as a model for observed fish mortality provided a clear relationship between accumulation and toxicity. Investigation of gill Cu accumulation may shed light on the different accumulation strategies from the two exposure pathways. This correlation offers potential for the use of branchial Cu concentration as an indicator of long-term Cu toxicity, allowing for differences in the relative importance of the uptake pathways in different field situations.


Asunto(s)
Cobre/farmacocinética , Cobre/toxicidad , Dorada/metabolismo , Contaminantes Químicos del Agua/farmacocinética , Contaminantes Químicos del Agua/toxicidad , Animales , Dieta , Branquias/metabolismo , Mucosa Intestinal/metabolismo , Hígado/metabolismo , Músculos/metabolismo
4.
Environ Sci Technol ; 46(14): 7621-8, 2012 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-22697255

RESUMEN

Predicting the environmental impact of engineered nanomaterials (ENMs) is increasingly important owing to the prevalence of emerging nanotechnologies. We derived waterborne uptake and efflux rate constants for the estuarine snail, Peringia ulvae, exposed to dissolved Ag (AgNO(3)) and silver nanoparticles (Ag NPs), using biodynamic modeling. Uptake rates demonstrated that dissolved Ag is twice as bioavailable as Ag in nanoparticle form. Biphasic loss dynamics revealed the faster elimination of Ag from Ag NPs at the start of depuration, but similar slow efflux rate constants. The integration of biodynamic parameters into our model accurately predicted Ag tissue burdens during chronic exposure with 85% of predicted values within a factor of 2 of observed values. Zeta potentials for the Ag NPs were lower in estuarine waters than in waters of less salinity; and uptake rates in P. ulvae were slower than reported for the freshwater snail Lymnaea stagnalis in similar experiments. This suggests aggregation of Ag NPs occurs in estuarine waters and reduces, but does not eliminate, bioavailability of Ag from the Ag NPs. Biodynamic modeling provides an effective methodology to determine bioavailable metal concentrations (originating from metal and metal-oxide nanoparticles) in the environment and may aid future ENM risk assessment.


Asunto(s)
Monitoreo del Ambiente , Nanopartículas del Metal/toxicidad , Modelos Biológicos , Tamaño de la Partícula , Plata/toxicidad , Caracoles/efectos de los fármacos , Caracoles/metabolismo , Animales , Hidrodinámica , Nanopartículas del Metal/química , Ríos , Agua de Mar/química , Plata/química , Suspensiones , Factores de Tiempo
5.
Environ Sci Technol ; 45(10): 4630-6, 2011 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-21517067

RESUMEN

Silver nanoparticles (AgNPs) are widely used which may result in environmental impacts, notably within aquatic ecosystems. As estuarine sediments are sinks for numerous pollutants, but also habitat and food for deposit feeders such as Nereis diversicolor, ingested sediments must be investigated as an important route of uptake for NPs. N. diversicolor were fed sediment spiked with either citrate capped AgNPs (30 ± 5 nm) or aqueous Ag for 10 days. Postexposure AgNPs were observed in the lumen of exposed animals, and three lines of evidence indicated direct internalization of AgNPs into the gut epithelium. With TEM, electron-dense particles resembling AgNPs were observed associated with the apical plasma membrane, in endocytotic pits and in endosomes. Energy dispersive X-ray analysis (EDX) confirmed the presence of Ag in these particles, which were absent in controls. Subcellular fractionation revealed that Ag accumulated from AgNPs was predominantly associated with inorganic granules, organelles, and the heat denatured proteins; whereas dissolved Ag was localized to the metallothionein fraction. Collectively, these results indicate separate routes of cellular internalization and differing in vivo fates of Ag delivered in dissolved and NP form. For AgNPs an endocytotic pathway appears to be a key route of cellular uptake.


Asunto(s)
Células Epiteliales/metabolismo , Nanopartículas del Metal/análisis , Poliquetos/efectos de los fármacos , Plata/metabolismo , Contaminantes Químicos del Agua/metabolismo , Animales , Células Epiteliales/efectos de los fármacos , Células Epiteliales/ultraestructura , Nanopartículas del Metal/toxicidad , Nanopartículas del Metal/ultraestructura , Microscopía Electrónica de Transmisión , Poliquetos/metabolismo , Poliquetos/ultraestructura , Plata/toxicidad , Contaminantes Químicos del Agua/toxicidad
6.
Environ Pollut ; 276: 116721, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33601199

RESUMEN

Historical mining activities cause widespread, long-term trace metal contamination of freshwater ecosystems. However, measuring trace metal bioavailability has proven difficult, because it depends on many factors, not least concentrations in water, sediment and habitat. Simple tools are needed to assess bioavailabilities. The use of biomonitors has been widely advocated to provide a realistic measure. To date there have been few attempts to identify ubiquitous patterns of trace metal accumulation within and between freshwater biomonitors at geographical scales relevant to trace metal contamination. Here we address this through a nationwide collection of freshwater biomonitors (species of Gammarus, Leuctra, Baetis, Rhyacophila, Hydropsyche) from 99 English and Welsh stream sites spanning a gradient of high to low trace metal loading. The study tested for inter-biomonitor variation in trace metal body burden, and for congruence amongst accumulations of trace metals within taxa and between taxa across the gradient. In general, significant differences in trace metal body burden occurred between taxa: Gammarus sp. was the most different compared with insect biomonitors. Bivariate relationships between trace metals within biomonitors reflected trace metal profiles in the environment. Strong correlations between some trace metals suggested accumulation was also influenced by physiological pathways. Bivariate relationships between insect biomonitors for body burdens of As, Cu, Mn and Pb were highly consistent. Our data show that irrespective of taxonomic or ecological differences, there is a commonality of response amongst insect taxa, indicating one or more could provide consistent measures of trace metal bioavailability.


Asunto(s)
Metales Pesados , Oligoelementos , Contaminantes Químicos del Agua , Animales , Ecosistema , Monitoreo del Ambiente , Metales/análisis , Oligoelementos/análisis , Contaminantes Químicos del Agua/análisis
7.
Food Chem Toxicol ; 46(6): 2010-22, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18329777

RESUMEN

Maximum acceptable concentrations of metals in food - based on total concentrations - have been established in many countries. To improve risk assessment, it would be better to take into account bioaccessible concentrations. A total of seven species of molluscs from France, UK and Hong Kong was examined in this study including clams, mussels, oysters, scallops and gastropods. The species which have total metal concentrations higher than the most severe food security limits are mainly oysters (all of the three studied species), the gastropod Buccinum undatum for cadmium and zinc, and scallops for cadmium. The lowest bioaccessibility (in % extractability with gut juices) was observed for silver (median for all of the species: 14%), it was moderate for lead (median: 33%) and higher for cadmium, zinc and copper (medians were respectively 54%, 65%, and 70%). In most cases, bioaccessible concentrations remained higher than the safety limits, except for cadmium in scallops and zinc in B. undatum. The influence of feeding habit (masticated or swallowed, addition of vinegar or lemon) on metal bioaccessibility in oysters is limited. On the contrary, cooking the gastropods decreased the bioaccessibility of metals, except silver.


Asunto(s)
Metales/análisis , Mariscos/análisis , Animales , Asia , Bivalvos , Culinaria , Europa (Continente) , Glándulas Exocrinas/química , Conducta Alimentaria , Contaminación de Alimentos/análisis , Congelación , Humanos , Metales/metabolismo , Mya , Ostreidae , Pectinidae , Control de Calidad , Análisis de Regresión , Especificidad de la Especie
8.
Aquat Toxicol ; 89(1): 47-54, 2008 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-18619682

RESUMEN

This study investigated the kinetics of Cd bioaccumulation, detoxification, subcellular distribution, and efflux in the nereid polychaete Perinereis aibuhitensis after Cd pre-exposure. Cd pre-exposure increased the Cd body burden in the worms, but did not affect the overall Cd uptake and efflux rates and metallothionein-like protein (MTLP) concentrations. During short-term exposure to dissolved Cd, Cd in the cytosolic fraction increased after Cd pre-exposure, and this fraction also increased during the Cd efflux period, indicating that the insoluble fraction of Cd was presumably lost at a faster rate than the loss of cytosolic Cd. Even though the MTLP concentration remained comparable after Cd pre-exposure, both the MTLP synthesis rate and the degradation rate increased, thus leading to a high MTLP turnover in the Cd-exposed worms. However, Cd uptake and efflux into different protein size fractions did not follow the patterns of MTLP synthesis and degradation, strongly suggesting that Cd kinetics is decoupled from the MTLP kinetics in the worms. Our study adds to an increasing body of evidence on the complicated relationship between metal biokinetics and MTLP kinetics in different groups of marine invertebrates which have strong contrasts in their metal handling strategies.


Asunto(s)
Cadmio/efectos adversos , Cadmio/farmacocinética , Metalotioneína/metabolismo , Poliquetos/efectos de los fármacos , Poliquetos/metabolismo , Animales , Transporte Biológico/fisiología , Metales/efectos adversos , Metales/farmacocinética , Contaminantes Químicos del Agua/efectos adversos , Contaminantes Químicos del Agua/farmacocinética
9.
Environ Int ; 33(4): 576-82, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-16814385

RESUMEN

Aquatic invertebrates take up and accumulate trace metals whether essential or non-essential, all of which have the potential to cause toxic effects. Subsequent tissue and body concentrations of accumulated trace metals show enormous variability across metals and invertebrate taxa. Accumulated metal concentrations are interpreted in terms of different trace metal accumulation patterns, dividing accumulated metals into two components - metabolically available metal and stored detoxified metal. Examples of different accumulation patterns are described from crustaceans but have a general applicability to all aquatic invertebrates. Toxicity does not depend on total accumulated metal concentration but is related to a threshold concentration of internal metabolically available metal. Toxicity ensues when the rate of metal uptake from all sources exceeds the combined rates of detoxification and excretion (if present) of the metal concerned. The biodynamic model of trace metal bioaccumulation allows the prediction and explanation of widely differing accumulated trace metal concentrations in organisms, combining geochemical analyses of environmental metal concentrations with the measurement of key physiological parameters for a species from the site under consideration. The combination of the biodynamic model as a unified explanation of metal bioaccumulation with an understanding of the relationship between accumulation and toxicity sets the stage for a realistic understanding of the significance of trace metal concentrations in aquatic invertebrates.


Asunto(s)
Metales/farmacocinética , Metales/toxicidad , Oligoelementos/farmacocinética , Oligoelementos/toxicidad
10.
Ecotoxicol Environ Saf ; 66(3): 402-11, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16620980

RESUMEN

Suborganismal responses to toxicants can be sensitive tools to assess marine pollution, but their ecological significance is a matter of debate. Among these biomarkers, those linked to reproduction are most probably related to populational effects. To test this hypothesis, Nereis diversicolor were collected in the multipolluted Seine estuary and the comparatively clean Authie estuary (France). Energy reserves were higher in Authie worms, suggesting a better physiological status. The number of oocytes per female was higher for the polychaetes from the Authie, but it was related to the size of animals, which was higher at this site. Densities of worms were depleted in the Seine compared to those in Authie. Demographic structure of the Seine population was also altered. The concomitant changes in energy reserves, egg production, and population structure and density suggest that the effects on biomarkers and at the population level are related.


Asunto(s)
Poliquetos/efectos de los fármacos , Contaminantes del Agua/toxicidad , Animales , Biomarcadores/metabolismo , Ecosistema , Monitoreo del Ambiente , Femenino , Francia , Glucógeno/metabolismo , Metabolismo de los Lípidos , Poliquetos/fisiología , Densidad de Población , Proteínas/metabolismo , Reproducción/efectos de los fármacos
11.
Water Res ; 40(9): 1805-10, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16620902

RESUMEN

The relative discriminatory powers of two trace metal biomonitors in European streams (the amphipod crustacean Gammarus fossarum and mayfly larvae of the genus Baetis-B. rhodani and B. vernus) are compared by discriminant function analysis using data from streams draining a zinc and lead mining area of Upper Silesia, Poland. The mayfly larvae (whether or not distinguished into the two separate species) had the better discriminatory power to distinguish between sites on the basis of local bioavailabilities of cadmium, copper, iron, lead and zinc. The bioavailabilities of the two metals lead and cadmium were the major local contributing factors to the stronger discrimination shown by the Baetis larvae.


Asunto(s)
Anfípodos/metabolismo , Monitoreo del Ambiente/métodos , Agua Dulce , Insectos/metabolismo , Metales Pesados/farmacocinética , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/farmacocinética , Animales , Metales Pesados/análisis , Polonia , Sensibilidad y Especificidad , Distribución Tisular
12.
Mar Environ Res ; 61(4): 439-55, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16574213

RESUMEN

Samples of 5 bivalve molluscs (Crassostrea rhizophorae, Mytella charruana, Anomalocardia brasiliana, Anadara ovalis, Phacoides pectinata), 2 barnacles (Fistulobalanus citerosum, Balanus amphitrite) and leaves of the mangrove tree Rhizophora mangle were collected from up to 11 sites in two estuaries in Natal, Brazil--the comparatively contaminated Potengi estuary and the comparatively uncontaminated Curimataú estuary. Specimens were analysed for the trace metals Zn, Cu, Cd, Fe, Mn and Ni, and a comparative assessment made of the power of the different species as trace metal biomonitors. Four of the 5 bivalves (not P. pectinata) take up metals from solution and suspended material (food source), while P. pectinata as a lucinid with symbiotic chemosynthetic bacteria takes up metals from dissolved sources only. The organisms with the strongest net accumulation of particular metals showed the greatest discrimination between trace metal bioavailabilities between sites. Barnacles (F. citerosum) showed the best discrimination, but oysters (C. rhizophorae) are particularly recommended as biomonitors given their strong accumulation patterns for many trace metals, their large size and their local abundance.


Asunto(s)
Bivalvos/química , Monitoreo del Ambiente/métodos , Metales Pesados/análisis , Rhizophoraceae/química , Thoracica/química , Análisis de Varianza , Animales , Brasil , Hojas de la Planta/química
13.
Environ Pollut ; 216: 793-805, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27357485

RESUMEN

Demonstration of an ecotoxicological effect of raised toxic metal bioavailabilities on benthic macroinvertebrate communities in contaminated freshwater streams typically requires the labour-intensive identification and quantification of such communities before the application of multivariate statistical analysis. A simpler approach is the use of accumulated trace metal concentrations in a metal-resistant biomonitor to define thresholds that indicate the presence of raised trace metal bioavailabilities causing ecotoxicological responses in populations of more metal-sensitive members of the community. We explore further the hypothesis that concentrations of toxic metals in larvae of species of the caddisfly genus Hydropsyche can be used to predict metal-driven ecotoxicological responses in more metal-sensitive mayflies, especially ephemerellid and heptageniid mayflies, in metal-contaminated rivers. Comparative investigation of two caddisflies, Hydropsyche siltalai and Hydropsyche angustipennis, from metal-contaminated rivers in Cornwall and Upper Silesia, Poland respectively, has provided preliminary evidence that this hypothesis is applicable across caddisfly species and contaminated river systems. Use of a combined toxic unit approach, relying on independent data sets, suggested that copper and probably also arsenic are the drivers of mayfly ecotoxicity in the River Hayle and the Red River in Cornwall, while cadmium, lead and zinc are the toxic agents in the Biala Przemsza River in Poland. This approach has great potential as a simple tool to detect the more subtle effects of mixed trace metal contamination in freshwater systems. An informed choice of suitable biomonitor extends the principle to different freshwater habitats over different ranges of severity of trace metal contamination.


Asunto(s)
Monitoreo del Ambiente , Intoxicación por Metales Pesados , Insectos/efectos de los fármacos , Intoxicación , Ríos , Contaminantes Químicos del Agua/toxicidad , Animales , Disponibilidad Biológica , Ecosistema , Larva , Polonia , Oligoelementos/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/farmacocinética
14.
Mar Environ Res ; 60(3): 339-54, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15769503

RESUMEN

Juveniles of the dendrobranchiate decapod Penaeus indicus take up radiolabelled cadmium from solution over the exposure concentration range of 1.8-31.5 microg L(-1), with an uptake rate constant of 0.090 L g(-1)d(-1) at 15 salinity and 25 degrees C. New cadmium taken up is added to the existing cadmium content of the prawn with no significant excretion, and the rate of accumulation of radiolabelled cadmium is a measure of the absolute cadmium uptake rate from solution. Moulting had no significant effect on the accumulation of cadmium. Newly accumulated cadmium is distributed to all organs with the highest proportions of body content being found in the hepatopancreas, exoskeleton, gills and remaining soft tissues, the hepatopancreas and gills containing the highest labelled cadmium concentrations. Like other crustaceans, penaeid prawns inhabiting anthropogenically contaminated coastal waters with raised cadmium bioavailabilities can be expected to contain raised body concentrations of cadmium. Cadmium concentrations of most field-collected adult penaeids are relatively low, as a probable consequence of the growth dilution of their cadmium contents as a result of the rapid growth rates of penaeid prawns.


Asunto(s)
Cadmio/farmacocinética , Penaeidae/metabolismo , Animales , Cinética , Espectrofotometría Atómica
15.
Sci China C Life Sci ; 48 Suppl 1: 110-7, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-16089336

RESUMEN

Barnacles have very high accumulated trace metal body concentrations that vary with local trace metal bioavailabilities and represent integrated measures of the supply of bioavailable metals. Pioneering work in Chinese waters in Hong Kong highlighted the potential value of barnacles (particularly Balanus amphitrite) as trace metal biomonitors in coastal waters, identifying differences in local trace metal bioavailabilities over space and time. Work in Hong Kong has also shown that although barnacles have very high rates of trace metal uptake from solution, they also have very high trace metal assimilation efficiencies from the diet. High assimilation efficiencies coupled with high ingestion rates ensure that trophic uptake is by far the dominant trace metal uptake route in barnacles, as verified for cadmium and zinc. Kinetic modelling has shown that low efflux rate constants and high uptake rates from the diet combine to bring about accumulated trace metal concentrations in barnacles that are amongst the highest known in marine invertebrates.


Asunto(s)
Metales Pesados/análisis , Thoracica/metabolismo , Oligoelementos/análisis , Animales , Cadmio/análisis , Cadmio/farmacocinética , Cobre/análisis , Cobre/farmacocinética , Monitoreo del Ambiente/métodos , Metales Pesados/farmacocinética , Agua de Mar/análisis , Oligoelementos/farmacocinética , Contaminantes Químicos del Agua/análisis , Zinc/análisis , Zinc/farmacocinética
16.
Aquat Toxicol ; 162: 102-108, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25797531

RESUMEN

Invertebrates typically carry out detoxification of accumulated metals. There is, therefore, no threshold total body concentration of accumulated metal initiating toxicity, the onset of toxic effects rather being related to a critical concentration of metabolically available (MA) accumulated metal. The challenge remains as to whether any particular combination of subcellular fractions of accumulated metal can be identified to represent this theoretical MA component. One candidate combined fraction is the so-termed metal sensitive fraction (MSF), consisting of metal bound to organelles and non-detoxificatory soluble proteins. In this study, we used laboratory zinc accumulation and toxicity data for four populations of the oyster Crassostrea hongkongensis with different histories of zinc exposure in the field to address the challenge. We conclude that in a 'control' population of the oyster, the MSF does approximate to the theoretical metabolically available zinc concentration. In populations with a history of field exposure to raised zinc bioavailabilities, however, the MSF would include more zinc detoxified in the lysosome component of organelle-bound metal, and the MSF in such populations would deviate more from the theoretical MA metal concentration.


Asunto(s)
Crassostrea/efectos de los fármacos , Intoxicación por Metales Pesados , Contaminantes Químicos del Agua/farmacocinética , Zinc/farmacocinética , Animales , Disponibilidad Biológica , Crassostrea/metabolismo , Inactivación Metabólica , Metales Pesados/metabolismo , Metales Pesados/farmacocinética , Metales Pesados/toxicidad , Intoxicación/metabolismo , Fracciones Subcelulares/metabolismo , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/toxicidad , Zinc/metabolismo , Zinc/toxicidad
17.
Nanotoxicology ; 9(4): 493-501, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25137295

RESUMEN

Mechanisms involved in the uptake of Ag NPs, and NPs in general, have been long debated within nano-ecotoxicology. In vitro studies provide evidence of the different available uptake pathways, but in vivo demonstrations are lacking. In this study, pharmacological inhibitors were employed to block specific uptake pathways that have been implicated in the transport of metal NPs and aqueous metal forms; phenamil (inhibits Na(+) channel), bafilomycin A1 (H(+) proton pump), amantadine (clathrin-mediated endocytosis), nystatin (caveolae-mediated endocytosis) and phenylarsine oxide (PAO, macropinocytosis). Peringia ulvae (snails) were exposed to 150 µg Ag L(-1) added as citrate capped Ag NPs or aqueous Ag (AgNO3) in combination with inhibitor treatment (determined by preliminary studies). Reductions in accumulated tissue burdens caused by the inhibitors were compared to control exposures (i.e. no inhibition) after 6 and 24 h. No inhibitor treatment completely eliminated the uptake of Ag in either aqueous or NP form, but all inhibitor treatments, except phenamil, significantly reduced the uptake of Ag presented as Ag NPs. Clathrin- and caveolae-mediated endocytosis appear to be mechanisms exploited by Ag NPs, with the latter pathway only active at 24 h. Inhibition of the H(+) proton pump showed that a portion of Ag NP uptake is achieved as aqueous Ag and is explained by the dissolution of the particles (∼25% in 24 h). This in vivo study demonstrates that uptake of Ag from Ag NPs is achieved by multiple pathways and that these pathways are simultaneously active.


Asunto(s)
Nanopartículas del Metal , Plata/metabolismo , Caracoles/metabolismo , Animales , Estuarios
18.
Environ Pollut ; 198: 32-40, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25549865

RESUMEN

The impact of Ag NPs on sediment-dwelling organisms has received relatively little attention, particularly in linking bioaccumulation to oxidative injury. The polychaete Nereis diversicolor was exposed to sediments spiked with dissolved Ag (added as AgNO3), Ag NPs (63 ± 27 nm) and larger bulk Ag particles (202 ± 56 µm), for up to 11 days at sublethal concentrations (nominally 2.5, 5, 10 µg Ag g(-1) sediment (dw)). There were concentration- and time-dependent differences in the accumulation of the three Ag forms, but all three forms elicited an oxidative stress response. In the cases of Ag NPs and bulk Ag particles, changes in antioxidant markers (glutathione, SOD, CAT, GPx, SeGPx, GST and GR) occurred without significant Ag accumulation. Differences in biomarker profiles between the three Ag forms suggest that the mechanism of oxidative stress caused by particulate Ag is distinct from that of dissolved Ag.


Asunto(s)
Estrés Oxidativo , Poliquetos/fisiología , Plata/metabolismo , Contaminantes Químicos del Agua/metabolismo , Animales , Biomarcadores/metabolismo , Glutatión , Poliquetos/metabolismo , Plata/toxicidad , Contaminantes Químicos del Agua/toxicidad
19.
Aquat Toxicol ; 161: 196-207, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25710448

RESUMEN

Biodynamic modeling was used to investigate the uptake and bioaccumulation of arsenic and silver from water and food by two Hydropsychid caddisfly larvae: Hydropsyche siltalai and Hydropsyche pellucidula. Radiotracer techniques determined the uptake rate constants of arsenic and silver from water, and assimilation efficiencies from food, and their subsequent loss rate constants after accumulation from either route. The uptake rate constants (±SE) of As and Ag from solution were 0.021±0.005 and 0.350±0.049Lg(-1)day(-1), respectively, for H. siltalai, and 0.435±0.054 and 0.277±0.021Lg(-1)day(-1), respectively, for H. pellucidula in moderately hard synthetic water at 10°C. The assimilation efficiencies (±SE) of As and Ag from radiolabeled ingested food were 46.0±7.7% and 75.7±3.6%, respectively, for H. siltalai, and 61.0±4.2% and 52.6±8.6%, respectively, for H. pellucidula. Ag, but not As, AEs were significantly different between species. The AE of Ag differed from the AE of As in H. siltalai, but not in H. pellucidula. Mean efflux rate constants after accumulation of metals from solution or food ranged from 0.039 to 0.190day(-1). The efflux rate constants of As and Ag accumulated from solution were significantly lower than those of As and Ag assimilated from ingested food in both species. Experimentally derived ku and ke values were then used to predict As and Ag tissue concentrations in hydropsychids collected from 13 UK sites, including metal-contaminated streams in Cornwall. Arsenic and silver concentrations in environmental water and food (suspended particles) samples were measured. Biodynamic models successfully predicted accumulated As and Ag concentrations in resident H. siltalai and H. pellucidula at each site. The models also showed that more than 95% of accumulated As and almost 100% of accumulated Ag in H. siltalai and H. pellucidula are derived from ingested food rather than from water.


Asunto(s)
Arsénico/farmacocinética , Insectos/metabolismo , Modelos Teóricos , Plata/farmacocinética , Animales , Larva/metabolismo , Contaminantes Químicos del Agua/farmacocinética
20.
J Inorg Biochem ; 98(6): 1095-102, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15149820

RESUMEN

Metal-containing granules were isolated from specimens of the barnacle Tetraclita squamosa collected from a metal contaminated site in Hong Kong. The chemical composition, crystallographic and morphological properties of the deposits were analysed by X-ray powder diffraction, electron microscopy, energy dispersive analysis by X-rays and infrared spectroscopy. The most abundant metals were iron, calcium and zinc and the major anion was phosphate. Oxalates, carbonates and sulfur derivates were also found in small amounts. The deposits were amorphous to X-ray and electron diffraction and were approximately spherical in shape with diameters between 100 and 500 nm.


Asunto(s)
Metales/química , Thoracica/química , Animales , Aniones/química , Espectrometría por Rayos X , Espectrofotometría Infrarroja , Thoracica/ultraestructura
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