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Venel Z, Tabuteau H, Pradel A, Pascal PY, Grassl B, El Hadri H, Baudrimont M, Gigault J. Environmental Fate Modeling of Nanoplastics in a Salinity Gradient Using a Lab-on-a-Chip: Where Does the Nanoscale Fraction of Plastic Debris Accumulate? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:3001-3008. [PMID: 33566594 DOI: 10.1021/acs.est.0c07545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The aim of this study is to demonstrate how the flow and diffusion of nanoplastics through a salinity gradient (SG), as observed in mangrove swamps (MSPs), influence their aggregation pathways. These two parameters have never yet been used to evaluate the fate and behavior of colloids in the environment, since they cannot be incorporated into classical experimental setups. Land-sea continuums, such as estuaries and MSP systems, are known to be environmentally reactive interfaces that influence the colloidal distribution of pollutants. Using a microfluidic approach to reproduce the SG and its dynamics, the results show that nanoplastics arriving in a MSP are fractionated. First, a substantial fraction rapidly aggregates to reach the microscale, principally governed by an orthokinetic aggregation process and diffusiophoresis drift. These large nanoplastic aggregates eventually float near the water's surface or settle into the sediment at the bottom of the MSP, depending on their density. The second, smaller fraction remains stable and is transported toward the saline environment. This distribution results from the combined action of the spatial salt concentration gradient and orthokinetic aggregation, which is largely underestimated in the literature. Due to nanoplastics' reactive behavior, the present work demonstrates that mangrove and estuarine systems need to be better examined regarding plastic pollution.
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Affiliation(s)
- Zélie Venel
- Géosciences Rennes, UMR6118, CNRS/Université de Rennes 1, Rennes 35042, France
- EPOC, UMR5805, CNRS/Université de Bordeaux, Bordeaux 33000, France
| | - Hervé Tabuteau
- IPR, UMR6251, CNRS/Université de Rennes 1, Rennes 35042, France
| | - Alice Pradel
- Géosciences Rennes, UMR6118, CNRS/Université de Rennes 1, Rennes 35042, France
| | - Pierre-Yves Pascal
- UMR 7138 Evolution Paris-Seine, Equipe Biologie de la Mangrove, Laboratoire de Biologie Marine, Université des Antilles, Pointe-a-Pitre 97157, France
| | - Bruno Grassl
- IPREM, UMR5254, CNRS/Université de Pau et des Pays de l'Adour, Pau 64053, France
| | - Hind El Hadri
- IPREM, UMR5254, CNRS/Université de Pau et des Pays de l'Adour, Pau 64053, France
| | | | - Julien Gigault
- Géosciences Rennes, UMR6118, CNRS/Université de Rennes 1, Rennes 35042, France
- TAKUVIK, UMI3376, CNRS/Université Laval, Québec G1V 0A6, Canada
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Mariano S, Panzarini E, Inverno MD, Voulvoulis N, Dini L. Toxicity, Bioaccumulation and Biotransformation of Glucose-Capped Silver Nanoparticles in Green Microalgae Chlorella vulgaris. NANOMATERIALS 2020; 10:nano10071377. [PMID: 32679737 PMCID: PMC7408452 DOI: 10.3390/nano10071377] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 01/16/2023]
Abstract
Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials in consumer products. When discharged into the aquatic environment AgNPs can cause toxicity to aquatic biota, through mechanisms that are still under debate, thus rendering the nanoparticles (NPs) effects evaluation a necessary step. Different aquatic organism models, i.e., microalgae, mussels, Daphnia magna, sea urchins and Danio rerio, etc. have been largely exploited for NPs toxicity assessment. On the other hand, alternative biological microorganisms abundantly present in nature, i.e., microalgae, are nowadays exploited as a potential sink for removal of toxic substances from the environment. Indeed, the green microalgae Chlorella vulgaris is one of the most used microorganisms for waste treatment. With the aim to verify the possible involvement of C. vulgaris not only as a model microorganism of NPs toxicity but also for the protection toward NPs pollution, we used these microalgae to measure the AgNPs biotoxicity and bioaccumulation. In particular, to exclude any toxicity derived by Ag+ ions release, green chemistry-synthesised and glucose-coated AgNPs (AgNPs-G) were used. C. vulgaris actively internalised AgNPs-G whose amount increases in a time- and dose-dependent manner. The internalised NPs, found inside large vacuoles, were not released back into the medium, even after 1 week, and did not undergo biotransformation since AgNPs-G maintained their crystalline nature. Biotoxicity of AgNPs-G causes an exposure time and AgNPs-G dose-dependent growth reduction and a decrease in chlorophyll-a amount. These results confirm C. vulgaris as a bioaccumulating microalgae for possible use in environmental protection.
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Affiliation(s)
- Stefania Mariano
- Department of Biological and Environmental Science and Technology, University of Salento, 73100 Lecce, Italy; (S.M.); (E.P.)
| | - Elisa Panzarini
- Department of Biological and Environmental Science and Technology, University of Salento, 73100 Lecce, Italy; (S.M.); (E.P.)
| | - Maria D. Inverno
- Centre for Environmental Policy, Imperial College London, London SW7 2AZ, UK; (M.D.I.); (N.V.)
| | - Nick Voulvoulis
- Centre for Environmental Policy, Imperial College London, London SW7 2AZ, UK; (M.D.I.); (N.V.)
| | - Luciana Dini
- Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy
- CNR Nanotec, 73100 Lecce, Italy
- Correspondence: ; Tel.: +39-064-991-2306; Fax: +39-064991
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Rasmussen L, Olapade OA. Influence of zinc on bacterial populations and their proteolytic enzyme activities in freshwater environments: a cross-site comparison. Can J Microbiol 2016; 62:320-8. [PMID: 26877164 DOI: 10.1139/cjm-2015-0638] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Temporal responses of indigenous bacterial populations and proteolytic enzyme (i.e., aminopeptidase) activities in the bacterioplankton assemblages from 3 separate freshwater environments were examined after exposure to various zinc (Zn) concentrations under controlled microcosm conditions. Zn concentrations (ranging from 0 to 10 μmol/L) were added to water samples collected from the Kalamazoo River, Rice Creek, and Huron River and examined for bacterial abundance and aminopeptidase activities at various time intervals over a 48 h incubation period in the dark. The results showed that the Zn concentrations did not significantly influence total bacterial counts directly; however, aminopeptidase activities varied significantly to increasing zinc treatments over time. Also, analysis of variance and linear regression analyses revealed significant positive relationships between bacterial numbers and their hydrolytic enzyme activities, suggesting that both probably co-vary with increasing Zn concentrations in aquatic systems. The results from this study serve as additional evidence of the ecological role of Zn as an extracellular peptidase cofactor on the dynamics of bacterial assemblages in aquatic environments.
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Affiliation(s)
- Lauren Rasmussen
- Department of Biology and the Center for Sustainability and the Environment, Albion College, Albion, MI 49224, USA.,Department of Biology and the Center for Sustainability and the Environment, Albion College, Albion, MI 49224, USA
| | - Ola A Olapade
- Department of Biology and the Center for Sustainability and the Environment, Albion College, Albion, MI 49224, USA.,Department of Biology and the Center for Sustainability and the Environment, Albion College, Albion, MI 49224, USA
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4
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McKee GA, Kobiela ME, Hatcher PG. Effect of Michael adduction on peptide preservation in natural waters. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2087-2097. [PMID: 24946992 DOI: 10.1039/c4em00075g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The reaction of peptides with chemicals already present in natural waters (such as polycyclic aromatic hydrocarbons) is one method that has been suggested to preserve peptides for the longer term. In this study we test whether the reaction of tetrapeptides with a model quinone can help stabilise the peptide in one polluted riverine system, Elizabeth River in Virginia, USA. We found that there is almost no difference in rate constants between the peptide and its quinone adduct (e.g. 6.62 versus 6.86 per day for AVFA and its respective adduct). However, when monitoring the removal of the adduct from natural water, we identified two new compounds that are formed as a result of its decomposition. Using tandem mass spectrometry we identified potential structures and mechanisms for the formation of these new compounds. These new compounds are more recalcitrant than their parent peptide-quinone adduct, since they remain in solution for 3-10 times longer. Based on our findings we postulate that the reaction of peptides with quinones can help preserve sections of the original peptide following an initial rearrangement of the original adduct, potentially explaining why seemingly labile peptides are observed in most natural waters.
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Affiliation(s)
- G A McKee
- Department of Chemistry and Biochemistry, Old Dominion University, 4402 Elkhorn Avenue, Norfolk, VA 23529, USA.
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Vezzaro L, Eriksson E, Ledin A, Mikkelsen PS. Quantification of uncertainty in modelled partitioning and removal of heavy metals (Cu, Zn) in a stormwater retention pond and a biofilter. WATER RESEARCH 2012; 46:6891-6903. [PMID: 21982280 DOI: 10.1016/j.watres.2011.08.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 06/07/2011] [Accepted: 08/24/2011] [Indexed: 05/31/2023]
Abstract
Strategies for reduction of micropollutant (MP) discharges from stormwater drainage systems require accurate estimation of the potential MP removal in stormwater treatment systems. However, the high uncertainty commonly affecting stormwater runoff quality modelling also influences stormwater treatment models. This study identified the major sources of uncertainty when estimating the removal of copper and zinc in a retention pond and a biofilter by using a conceptual dynamic model which estimates MP partitioning between the dissolved and particulate phases as well as environmental fate based on substance-inherent properties. The two systems differ in their main removal processes (settling and filtration/sorption, respectively) and in the time resolution of the available measurements (composite samples and pollutographs). The most sensitive model factors, identified by using Global Sensitivity Analysis (GSA), were related to the physical characteristics of the simulated systems (flow and water losses) and to the fate processes related to Total Suspended Solids (TSS). The model prediction bounds were estimated by using the Generalized Likelihood Uncertainty Estimation (GLUE) technique. Composite samples and pollutographs produced similar prediction bounds for the pond and the biofilter, suggesting a limited influence of the temporal resolution of samples on the model prediction bounds. GLUE highlighted model structural uncertainty when modelling the biofilter, due to disregard of plant-driven evapotranspiration, underestimation of sorption and neglect of oversaturation with respect to minerals/salts. The results of this study however illustrate the potential for the application of conceptual dynamic fate models base on substance-inherent properties, in combination with available datasets and statistical methods, to estimate the MP removal in different stormwater treatment systems and compare with environmental quality standards targeting the dissolved MP fraction.
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Affiliation(s)
- L Vezzaro
- Department of Environmental Engineering (DTU Environment), Technical University of Denmark, Building 113, Miljoevej, 2800 Kgs. Lyngby, Denmark.
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Masson M, Blanc G, Schäfer J, Parlanti E, Le Coustumer P. Copper addition by organic matter degradation in the freshwater reaches of a turbid estuary. THE SCIENCE OF THE TOTAL ENVIRONMENT 2011; 409:1539-1549. [PMID: 21303715 DOI: 10.1016/j.scitotenv.2011.01.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 01/10/2011] [Accepted: 01/12/2011] [Indexed: 05/30/2023]
Abstract
This study reports on the relationship between copper (Cu) behavior and organic matter (OM) transformation along the turbidity gradient in the freshwater reaches of the Gironde Estuary. During a one-year survey, surface water and suspended particulate matter (SPM) were sampled at least monthly at three sites along the Garonne Branch, representing the main fluvial branch of the Gironde Estuary. Additionally, a longitudinal high resolution profile was sampled along the Garonne Branch, covering the turbidity gradient from the river water endmember to the maximum turbidity zone (MTZ). Seasonal variability and spatial distribution of Cu in both the dissolved phases (<0.2 μm, Cu(0.2) and <0.02 μm, Cu(0.02)) and particulate Cu (Cu(P)) clearly suggested Cu(0.2) addition during summer, that increased the Cu(0.2) concentrations by a factor ~2, mainly manifested by an increase in the Cu(0.02) fraction. At the annual timescale (2004), this internal Cu reactivity increased Cu(0.02) fluxes in the Garonne Branch by ~20% (3.6 t year(-1)), with the equivalent of ~2.9 t year(-1) derived from the Cu(P) fraction and ~0.7 t year(-1) from the colloidal (0.02-0.2 μm) fraction, without involving and/or affecting the Cu(C18) (hydrophobic metal-organic complexes) fraction. Combining data on Cu speciation with the results obtained by several independent techniques (DOC and POC measurements, 3D-fluorescence, and TEM) suggested close relationships between Cu behavior and OM transformation/restructuration along the turbidity gradient in the Garonne Branch. The observed Cu(0.02) addition was related to increasing humification (humification index HIX increased from 9 to 12, network formation) and labile OM degradation (Iγ/Iα ratio decreased from 0.70 to 0.44), going along with decreasing DOC and POC concentrations. Mass-balances suggest that in the studied system, degradation of OM may account for the release of ~25 μmol potentially bioaccessible Cu(0.02) per mole of particulate organic carbon mineralized.
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Affiliation(s)
- Matthieu Masson
- Université de Bordeaux, UMR 5805 EPOC-TGM, av. des Facultés, 33405 Talence Cedex, France
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Priadi C, Bourgeault A, Ayrault S, Gourlay-Francé C, Tusseau-Vuillemin MH, Bonté P, Mouchel JM. Spatio-temporal variability of solid, total dissolved and labile metal: passive vs. discrete sampling evaluation in river metal monitoring. ACTA ACUST UNITED AC 2011; 13:1470-9. [DOI: 10.1039/c0em00713g] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wilkie EM, Roach AC, Micevska T, Kelaher BP, Bishop MJ. Effects of a chelating resin on metal bioavailability and toxicity to estuarine invertebrates: divergent results of field and laboratory tests. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2010; 158:1261-1269. [PMID: 20193975 DOI: 10.1016/j.envpol.2010.01.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 01/27/2010] [Accepted: 01/28/2010] [Indexed: 05/28/2023]
Abstract
Benthic invertebrates can uptake metals through diffusion of free ion solutes, or ingestion of sediment-bound forms. This study investigated the efficacy of the metal chelating resin SIR 300 in adsorbing porewater metals and isolating pathways of metal exposure. A field experiment (Botany Bay, Sydney, Australia) and a laboratory toxicity test each manipulated the availability of porewater metals within contaminated and uncontaminated sediments. It was predicted that within contaminated sediments, the resin would adsorb porewater metals and reduce toxicity to invertebrates, but in uncontaminated sediments, the resin would not significantly affect these variables. Whereas in the laboratory, the resin produced the predicted results, in the field the resin increased porewater metal concentrations of contaminated sediments for at least 34 days and decreased abundances of four macroinvertebrate groups, and richness in all sediments. These contrasting findings highlight the limits of extrapolating the results of laboratory experiments to the field environment.
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Affiliation(s)
- Emma M Wilkie
- Department of Environmental Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia.
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9
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Beck AJ, Sañudo-Wilhelmy SA. Impact of water temperature and dissolved oxygen on copper cycling in an urban estuary. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:6103-6108. [PMID: 17937288 DOI: 10.1021/es062719y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An increasing body of evidence suggests that much of the trace metal contamination observed in coastal waters is no longer derived from point-source inputs, but instead originates from diffuse, non-point sources. Previous research has shown that water temperature and dissolved oxygen regulate non-point source processes such as sediment diagenesis; however, limited information is available regarding the effect of these variables on toxic trace metal cycling and speciation in natural waters. Here, we present data on the seasonal variation of dissolved Cu cycling in the Long Island Sound, an urban estuary adjacent to New York City. An operationally defined chemical speciation technique based on kinetic lability and organic complexation has been applied to examine the most ecologically relevant metal fraction. In contrast to the decrease from spring to summer observed in the total dissolved Cu pool (average +/- SD: 15.1 +/- 4.4 nM in spring and 11.8 +/- 3.5 nM in summer), our results revealed that in the highly impacted western LIS, levels of labile Cu reached higher levels in summer (range 3.6-7.7 nM) than in spring (range 1.5-3.9 nM). Labile Cu in surface waters of the western Sound appeared to have a wastewater source during spring high flow conditions, coinciding with elevated levels of sewage-derived Ag. Labile Cu elsewhere in the LIS during spring apparently resulted from fluvial input and mixing. During summer, labile Cu increased in bottom waters (at one site, bottom water labile Cu increased from 1.5 nM in spring to 7.7 nM in summer), and covariance with tracers of diagenetic remobilization (e.g., Mn) revealed a sedimentary source. Although total dissolved Cu showed no consistent trends with water quality parameters, labile Cu in bottom waters showed an inverse correlation with dissolved oxygen and a positive, exponential correlation with water temperature. These results suggest that future increases in coastal water temperatures may cause the benthic source of labile Cu to become proportionally more significant.
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Affiliation(s)
- Aaron J Beck
- Marine Sciences Research Center, Stony Brook University, Stony Brook, New York 11794-5000, USA.
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Chen Z, Cai Y, Solo-Gabriele H, Snyder GH, Cisar JL. Interactions of arsenic and the dissolved substances derived from turf soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:4659-65. [PMID: 16913121 DOI: 10.1021/es060619m] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Monosodium methanearsonate (MSMA) is frequently used as an herbicide for the control of weeds in turf grasses at golf courses in Florida. There are concerns about arsenic (As) contamination of local shallow groundwater from the application of MSMA. The distinction between "free" As and colloid-bound/complexed As in soil solution is important for understanding the mobility and bioavailability of As in the environment. In this study, the equilibrium membrane (500 and 3500 Da) dialysis method was employed to determine the "free" and "bound" As in water extracts of five types of golf-course soils containing coated and uncoated sands in various proportions with peat. All samples were evaluated for arsenic species (arsenite, AsIII and arsenate, AsV), dissolved organic matter, and additional constituents (iron, aluminum, and calcium). The impacts of microbial growth were evaluated by conducting experiments with and without the addition of sodium azide for one particular soil type. Results indicate that (1) the presence of peat in the soils plays a significant role in the distribution of As in the dissolved phase of soil solutions; (2) the majority of As present in the soil extracts from soils containing peat was associated with substances of molecular weight (MW) between 500 and 3500 Da; (3) the association of As and dissolved organic matter (DOM) in the soil solution strongly affected As bioavailability, thus determining As transformations via microorganism-mediated processes; and (4) the presence of peat greatly enhanced the release of iron, aluminum, and calcium from soil. Amendment of sand with peat is a common practice at Florida golf courses. However, the addition of peat will alter the properties of the soils, which in turn could affect As transport and transformation. The results of this study are useful for understanding the factors controlling As trapping and transport within porous soil media and in developing comprehensive plans for managing and remediating As contaminated environments, such as golf courses.
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Affiliation(s)
- Zhangrong Chen
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA
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Deheyn DD, Latz MI. Bioavailability of metals along a contamination gradient in San Diego Bay (California, USA). CHEMOSPHERE 2006; 63:818-34. [PMID: 16169051 DOI: 10.1016/j.chemosphere.2005.07.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 07/01/2005] [Accepted: 07/24/2005] [Indexed: 05/04/2023]
Abstract
San Diego Bay is heavily contaminated with metals, but little is known about their biological availability to local marine organisms. This study on 15 elements showed that concentrations of metals associated with sediment increased from the mouth to the back of the Bay while metals in seawater particulates were similar throughout the Bay. Metal bioavailability was assessed over 8weeks following transplant of the local brittlestar, Ophiothrix spiculata (Ophuroidea, Echinodermata), from outside to inside the Bay. Despite a gradient of contamination, brittlestars accumulated similar levels of metals throughout the Bay, suggesting that metal contamination occurred through dissolved metals as well as through the diet. Sediment transplanted in dialysis tubing in the Bay accumulated metals only when placed on the seafloor bottom, indicating greater metal bioavailability near the bottom; the level of accumulation was similar between the mouth and the back of the Bay. The results are consistent with a circulation pattern in which a bottom layer of seawater, enriched with metals, drains from the back to the mouth of the Bay. There was a positive correlation between metal concentration in brittlestars and tidal range, suggesting increased metal exposure due to bay-ocean water exchange. For brittlestar arms the correlation was higher at the mouth than the back of the Bay, indicating greater metal accumulation in arms from dissolved metals in seawater than from ingestion of metal contaminated diet. In contrast, for brittlestar disks the correlation was higher at the back of the Bay, indicative of metal accumulation mainly through the diet. The results highlight the importance of considering bioavailability and physical processes in environmental quality assessments.
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Affiliation(s)
- Dimitri D Deheyn
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, 92093-0202, USA.
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Vignati D, Camusso M, Dominik J. Estimation of the truly dissolved concentrations of Cd, Cu, Ni, and Zn in contrasting aquatic environments with a simple empirical model. Ecol Modell 2005. [DOI: 10.1016/j.ecolmodel.2004.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Vignati DAL, Dworak T, Ferrari B, Koukal B, Loizeau JL, Minouflet M, Camusso MI, Polesello S, Dominik J. Assessment of the geochemical role of colloids and their impact on contaminant toxicity in freshwaters: an example from the Lambro-Po system (Italy). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:489-497. [PMID: 15707048 DOI: 10.1021/es049322j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The role of colloids in regulating element transport, behavior, and bioavailability in aquatic systems is now well-established. It appears that further progress in this research field is being slowed by (i) a limited integration between the geochemical and the biological aspects of the research on colloids and (ii) a persistent gap between well-controlled laboratory studies and real field situations. This paper presents a simultaneous evaluation of the role of colloids in controlling element environmental fate and bioavailability at the confluence between a major river and a polluted tributary. Fractionation of trace elements among suspended particulate matter, colloids, and true solution suggests that colloids may play a role in the removal of trace elements from the water column to bed sediments during the mixing of the two rivers. Toxicity testing of water samples indicates that, in this specific system, contaminants associated with colloids can contribute to water toxicity for the rotifer Brachionus calyciflorus but not for the green alga Pseudokirchneriella subcapitata. To the best of our knowledge, the results for B. calyciflorus are the first ones pointing to the possible contribution of colloid-bound contaminants to water toxicity in environmental samples. Despite the uncertainties associated with field variability, the results of chemical analysis and toxicitytesting show several points of convergence. Following these observations, a few innovative research approaches are suggested to improve the understanding of trace element biogeochemistry in real field situations.
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Affiliation(s)
- Davide A L Vignati
- Institut F-A Forel and Centre d'Etudes en Sciences Naturelles et de l'Environnemnent, University of Geneva, CH-1290 Versoix, Switzerland.
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