135 results on '"Leermakers, Martine"'
Search Results
102. Trace metal pollution and its influence on the community structure of soft bottom molluscs in intertidal areas of the Dar es Salaam coast, Tanzania
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Rumisha, Cyrus, primary, Elskens, Marc, additional, Leermakers, Martine, additional, and Kochzius, Marc, additional
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- 2012
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103. Effect of bacterial mineralization of phytoplankton-derived phytodetritus on the release of arsenic, cobalt and manganese from muddy sediments in the Southern North Sea. A microcosm study
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Gillan, David C., primary, Pede, Annelies, additional, Sabbe, Koen, additional, Gao, Yue, additional, Leermakers, Martine, additional, Baeyens, Willy, additional, Louriño Cabana, Beatriz, additional, and Billon, Gabriel, additional
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- 2012
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104. Links between bacterial communities in marine sediments and trace metal geochemistry as measured by in situ DET/DGT approaches
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Gillan, David C., primary, Baeyens, Willy, additional, Bechara, Rafeh, additional, Billon, Gabriel, additional, Denis, Kevin, additional, Grosjean, Philippe, additional, Leermakers, Martine, additional, Lesven, Ludovic, additional, Pede, Annelies, additional, Sabbe, Koen, additional, and Gao, Yue, additional
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- 2012
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105. Response of diffusive equilibrium in thin films (DET) and diffusive gradients in thin films (DGT) trace metal profiles in sediments to phytodetritus mineralisation
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Gao, Yue, primary, Leermakers, Martine, additional, Pede, Annelies, additional, Magnier, Aurelie, additional, Sabbe, Koen, additional, Lourino Cabana, Beatriz, additional, Billon, Gabriel, additional, Baeyens, Willy, additional, and Gillan, David C., additional
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- 2012
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106. Sources of PCDD/Fs, non-ortho PCBs and PAHs in sediments of high and low impacted transboundary rivers (Belgium–France)
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Sanctorum, Hermes, primary, Elskens, Marc, additional, Leermakers, Martine, additional, Gao, Yue, additional, Charriau, Adeline, additional, Billon, Gabriel, additional, Goscinny, Séverine, additional, Cooman, Ward De, additional, and Baeyens, Willy, additional
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- 2011
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107. Spectral interferences in the analysis of cadmium in human blood by ICP-MS: comparison between high resolution sector field ICP-MS and quadrupole ICP-MS
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Vrijens, Jan, primary, Couck, Pedro, additional, Schroijen, Carmen, additional, Baeyens, Willy, additional, and Leermakers, Martine, additional
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- 2011
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108. Mercury accumulation in fish species from the Persian Gulf and in human hair from fishermen
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Agah, Homira, primary, Leermakers, Martine, additional, Gao, Yue, additional, Fatemi, S. M. R., additional, Katal, M. Mohseni, additional, Baeyens, Willy, additional, and Elskens, Marc, additional
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- 2009
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109. Distribution of Trace Elements in Sediments and Biota of Songkhla Lake, Southern Thailand
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Pradit, Siriporn, primary, Wattayakorn, Gullaya, additional, Angsupanich, Saowapa, additional, Baeyens, Willy, additional, and Leermakers, Martine, additional
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- 2009
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110. Dietary exposure to total and toxic arsenic in Belgium: Importance of arsenic speciation in North Sea fish
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Baeyens, Willy, primary, Gao, Yue, additional, De Galan, Sandra, additional, Bilau, Maaike, additional, Van Larebeke, Nicolas, additional, and Leermakers, Martine, additional
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- 2008
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111. Mercury speciation in the Persian Gulf sediments
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Agah, Homira, primary, Elskens, Marc, additional, Fatemi, S. Mohammad Reza, additional, Owfi, Fereidoon, additional, Baeyens, Willy, additional, and Leermakers, Martine, additional
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- 2008
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112. Accumulation of trace metals in the muscle and liver tissues of five fish species from the Persian Gulf
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Agah, Homira, primary, Leermakers, Martine, additional, Elskens, Marc, additional, Fatemi, S. Mohamad Rez, additional, and Baeyens, Willy, additional
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- 2008
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113. Speciation in Environmental Samples
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Baeyens, Willy, primary, De Gieter, Marjan, additional, Leermakers, Martine, additional, and Windal, Isabelle, additional
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- 2007
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114. Total Mercury and Methyl Mercury Concentrations in Fish from the Persian Gulf and the Caspian Sea
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Agah, Homira, primary, Leermakers, Martine, additional, Elskens, Marc, additional, Fatemi, S. Mohamad Reza, additional, and Baeyens, Willy, additional
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- 2006
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115. Mercury in environmental samples: Speciation, artifacts and validation
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Leermakers, Martine, primary, Baeyens, Willy, additional, Quevauviller, Philippe, additional, and Horvat, Milena, additional
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- 2005
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116. Correlations, partitioning and bioaccumulation of heavy metals between different compartments of Lake Balaton
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Nguyen, Hong Lien, primary, Leermakers, Martine, additional, Elskens, Marc, additional, De Ridder, Fjo, additional, Doan, Thai Hoa, additional, and Baeyens, Willy, additional
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- 2005
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117. Accumulation of trace metals in the muscle and liver tissues of five fish species from the Persian Gulf.
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Homira Agah, Leermakers, Martine, Elskens, Marc, Fatemi, S. Mohamad Rez, and Baeyens, Willy
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FISH physiology ,METALS & the environment ,TRACE metals ,INDUCTIVELY coupled plasma mass spectrometry ,HYDROGEN peroxide ,NITRIC acid ,PUBLIC health ,SEAFOOD ,CONSUMPTION (Economics) ,COOKING - Abstract
In this study, concentrations of 16 elements were quantified in muscles and livers of 141 fishes belonging to five commercially species. It was also our intention to evaluate potential risks to human health associated with seafood consumption. The grunt, flathead, greasy grouper, tiger-tooth croaker and silver pomfret fish species were obtained from Abadan, Deylam, Bushehr-Nirogah, Dayyer port, Lengeh port and Abbas port in Hormozgan, Bushehr and Khozesran provinces at the Iranian waters of the Persian Gulf. The contents of Al, As, Be, Cd, Cr, Co, Cu, Fe, Pb, Mn, Mo, Ni, Sb, Tl, V and Zn in fish muscles and livers were determined by Inductively Coupled Plasma Mass Spectrometry (ICP MS), after digestion in a CEM (Mars 5) microwave oven using nitric acid and hydrogen peroxide. Our results indicated that almost all metals were more accumulated in younger flathead, greasy grouper and tiger-tooth fishes. Contrary to the other fish species, grunt seems to stronger accumulating elements in the older fishes. Strong and positive correlations were observed in three or more of the fish species between V, Al, Fe, Tl, Co and Pb. The results confirmed that fish muscle and liver tissues appeared to be good bio-indicators for identification of coastal areas exposed to metallic contaminants. The results also showed that the element levels in the muscles of all fishes in our study were lower than the maximum allowable concentrations and pose no threat to public health, except for arsenic. [ABSTRACT FROM AUTHOR]
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- 2009
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118. Determination of methylmercury in natural waters by headspace gas chromatography with microwave-induced plasma detection after preconcentration on a resin containing dithiocarbamate groups
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Lansens, Patrick, primary, Meuleman, Carine, additional, Leermakers, Martine, additional, and Baeyens, Willy, additional
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- 1990
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119. Determination of metallic mercury and some organomercury compounds using atomic absorption spectrometry after amalgamation on a gold column.
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Baeyens, Willy and Leermakers, Martine
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- 1989
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120. Campanile gastropods as recorders of Eocene hothouse climate: A multi-proxy study with comparison with modern relatives.
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de Winter, Niels, Vellekoop, Johan, Clark, Alexander, Stassen, Peter, Petersen, Sierra, Scholz, Serena, Goderis, Steven, Snoeck, Christophe, Leermakers, Martine, Speijer, Robert, and Claeys, Philippe
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- 2019
121. Marine benthic hypoxia and its consequences for sediment-water exchanges and early diagenesis
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Plante, Audrey, Chou, Lei, Regnier, Pierre, Fagel, Nathalie, Grégoire, Marilaure, Arndt, Sandra, Leermakers, Martine, Rabouille, Christophe, and Capter, Arthur
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Black Sea ,Océanographie physique et chimique ,Hypoxia ,Early diagenesis - Abstract
The northwestern (NW) continental shelf of the Black Sea undergoes seasonal hypoxia. The benthic environment, the exchanges at the water-sediment interface and the diagenetic reactions are influenced by this phenomenon. In the framework of the BENTHOX project, two field cruises were conducted on the shelf in spring 2016 and in summer 2017.The first part of this investigation concerned the study of the impact of low oxygen levels in bottom waters on the diagenetic reactions. The microprofilings of geochemical parameters and the flux measurements showed both spatial and temporal variabilities in the benthic compartment of the NW continental shelf for the two seasons studied. The areas closest to the coasts exhibited the most important fluxes of oxygen consumption and of sulfate. These regions were strongly influenced by riverine inputs inducing a higher productivity and in turn resulting in an increase in the fluxes of organic matter deposited on the seabed.The diagenetic reactions were impacted by seasonal deoxygenation in bottom waters. The oxic respiration was less important in the summer as reflected by the shallower penetration depth of dissolved oxygen. Since 1995, the diffusive oxygen uptake (DOU) reported during hypoxic period indicated that the concentration of dissolved oxygen played an important role in the benthic exchange fluxes. Furthermore, a shallower reduction of sulphate and of Mn- and Fe-oxides observed in the sediments evidenced the impact of low oxygen levels on the diagenetic cascade. As a consequence, the benthic mineralization of organic matter was affected. During summer 2017, the oxic mineralization of organic carbon was less important and the contribution of the reducing species to oxygen consumption increased. The anaerobic mineralization of organic matter became thus the dominant process during the period of deoxygenation.The second part concerned the study of the sulfur and iron cycling in the shelf sediments during the low oxygen event of summer 2017. The sediments from the station close to the mouth of the Danube and that near the Dnieper exhibited a signature of detrital material different from that of the upper crust. The inputs of organic matter, in particular transported by the rivers, could influence the signal. The sediments of the NW shelf investigated were however of marine origin.Following the sulfate reduction already observed and mentioned above, the hydrogen sulfides produced were rapidly consumed as suggested by the low concentrations of acid volatile sulfide (AVS) and of the dissolved sulfide. The presence of pyrite in the upper layers of the sediments close to the water-sediment interface was plausible because the formation of pyrite in the water column had been reported due to the higher resistance of pyrite to oxidation compared to AVS (Wijsman et al. 2001). A non steady-state deposition was observed as suggested by Wijsman et al. (1999). It was characterized by an abrupt drop in the pyrite content caused possibly by fluctuations in salinity, dissolved O2 concentrations and organic matter fluxes.The non-reactive iron constituted the principal fraction of the total iron present in the sediments. Its contribution fell in the range reported for the marine sediments of the continental margins. A spatial variation of the concentration of highly reactive iron was nevertheless observed. Near the Dnieper mouth, the contents of reactive iron were lower and could be attributed to the less important fluvial inputs, to the sorption and/or precipitation processes or yet to the reallocation of the reactive iron of the shelf deposits towards the sediments in deep and euxinic waters.The last part of this thesis concerned the biogeochemistry of metals (Fe, Mn, Zn, Cu, Ni, Hg, Co and Cd) during the early diagenesis and the assessment of enrichment and pollution of these metals in the sediments of the shelf. The results showed that trace metals are probably linked to iron and manganese oxides as well as to sulphides. Ni and Zn could be involved in adsorption onto and co-precipitation with Fe- and Mn-oxides. Cu seemed to be associated preferentially to sulphides but no clear correlation was found. The enrichment and pollution of these metals in the shelf sediments showed spatial variability. The Danube delta area was enriched in Ni, Cu and Zn while the Odessa region was enriched in Co and Cd. The pollution of shelf sediments ranged from “unpolluted” to “very highly polluted”. Since the late 20th century, the heavy metal contents in shelf sediments remained stable in the Odessa region but increased in the Danube delta area., Le plateau continental du Nord-Ouest de la Mer Noire subit une hypoxie saisonnière. L'environnement benthique, l'échange à l'interface eau-sédiment et les réactions diagénétiques sont influencés par ce phénomène. Dans le cadre du projet BENTHOX, deux campagnes de prélèvement ont été menées sur le plateau au printemps 2016 et à l'été 2017 dans le but de comprendre ces changements.La première partie de cette recherche concerne l’impact des faibles concentrations en oxygène dans les eaux de fond sur les réactions diagénétiques. Les micro-profils de paramètres géochimiques et les mesures de flux ont montré des variabilités spatiales et temporelles dans le compartiment benthique pour les deux saisons étudiées. Les zones les plus proches des côtes ont présenté les flux les plus importants de consommation d'oxygène et de sulfate. Ces régions ont été fortement influencées par les apports fluviaux induisant une productivité plus élevée et entraînant à son tour une augmentation des flux de matière organique déposée sur le fond marin. Les réactions diagénétiques sont affectées par la désoxygénation saisonnière des eaux de fond. La respiration oxique etait moins importante en été comme en témoigne la profondeur de pénétration moins profonde de l’oxygène. Depuis 1995, l’absorption d’oxygène dissous (DOU) rapportée pendant la période limitée en oxygène a indiqué que la concentration d'oxygène dissous jouait un rôle important dans les flux d'échanges benthiques. De plus, une diminution de la profondeur à laquelle la réduction des sulfates et la réduction des oxydes métalliques témoigne de l'impact d'une faible concentration en oxygène sur la cascade diagénétique. En conséquence, la minéralisation benthique de la matière organique a été affectée. Au cours de l'été 2017, la minéralisation oxique du carbone a été moins importante et la contribution des espèces réductrices à la consommation d’oxygène a augmenté. La respiration anaérobie de la matière organique est ainsi devenue le processus dominant pendant la période d'hypoxie.La deuxième partie portait sur l'étude du cycle du soufre et du fer dans les sédiments du plateau lors de l'événement de faible teneur en oxygène de l'été 2017. Les sédiments de la station proche de l'embouchure du Danube et de celle du Dniepr présentaient une signature de matière détritique différente de celle de la croûte supérieure. Les apports de matière organique, notamment transportés par les rivières, pourraient influencer le signal. Les sédiments du plateau nord-ouest étudiés étaient cependant d'origine marine. Suite à la réduction du sulfate déjà observée et mentionnée ci-dessus, les sulfures d'hydrogène produits ont été rapidement consommés comme le suggèrent les faibles concentrations en sulfure acide volatil (AVS) et en sulfure dissous. La présence de pyrite dans les couches supérieures des sédiments près de l'interface eau-sédiment était plausible car la formation de pyrite dans la colonne d'eau avait été signalée en raison de la résistance plus élevée de la pyrite à l'oxydation par rapport à l'AVS (Wijsman et al. 2001). Un dépôt à l'état non stationnaire a été observé comme le suggèrent Wijsman et al. (1999). Elle a été caractérisée par une chute brutale de la teneur en pyrite causée peut-être par des fluctuations de salinité, des concentrations d'O2 dissous et des flux de matière organiqueLe fer non réactif constituait la fraction principale du fer total présent dans les sédiments. Sa contribution est tombée dans la gamme signalée pour les sédiments marins des marges continentales. Une variation spatiale de la concentration en fer hautement réactif a néanmoins été observée. Près de l'embouchure du Dniepr, les teneurs en fer réactif étaient plus faibles et pouvaient être attribuées aux apports fluviaux moins importants, aux processus de sorption et / ou de précipitation ou encore à la réallocation du fer réactif des dépôts du plateau vers les sédiments en profondeur et eaux euxiniques.La dernière partie de cette thèse concerne la biogéochimie des métaux (Fe, Mn, Zn, Cu, Ni, Hg, Co et Cd) lors de la diagenèse précoce et l'évaluation de l'enrichissement et de la pollution de ces métaux dans les sédiments du plateau. Les résultats ont montré que les métaux traces sont probablement liés aux oxydes de fer et de manganèse ainsi qu'aux sulfures. Ni et Zn pourraient être impliqués dans l'adsorption et la coprécipitation avec les oxydes de Fe et de Mn. Le Cu semble être associé préférentiellement aux sulfures mais aucune corrélation claire n'a été trouvée. L'enrichissement et la pollution de ces métaux dans les sédiments du plateau ont montré une variabilité spatiale. La zone du delta du Danube a été enrichie en Ni, Cu et Zn tandis que la région d'Odessa s'est enrichie en Co et Cd. La pollution des sédiments du plateau allait de « non polluée » à « très fortement polluée ». Depuis la fin du 20e siècle, la teneur en métaux lourds des sédiments du plateau est restée stable dans la région d'Odessa mais a augmenté dans la région du delta du Danube., Doctorat en Sciences, info:eu-repo/semantics/nonPublished
- Published
- 2020
122. Diffusive Gradients in Thin-films technique for uranium monitoring along a salinity gradient: A comparative study on the performance of Chelex-100, Dow-PIWBA, Diphonix, and Lewatit FO 36 resin gels in the Scheldt estuary.
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Smolíková, Vendula, Pelcová, Pavlína, Ridošková, Andrea, and Leermakers, Martine
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URANIUM , *SALINITY , *ESTUARIES , *PERFORMANCE theory , *INVERSE relationships (Mathematics) , *COMPARATIVE studies , *ELECTRODIALYSIS - Abstract
Monitoring of uranium in the environment using the Diffusive Gradients in Thin-films (DGT) technique gains in importance as it can provide unique information about the bioavailability of the element and allows its long-term in-situ measurement. Hence, in this study, four DGT binding phases (Chelex-100, Dow-PIWBA, Diphonix, and Lewatit FO 36 resins) were evaluated for uranium monitoring to assess the robustness of their performance in estuarine and marine environments. These DGTs were deployed along the Scheldt estuary (Belgium and the Netherlands) over four campaigns between 2014 and 2021. The DGT performance (ratio of the DGT-determined vs. dissolved U concentration in grab water sample) varied with the water salinity. The Chelex-100 DGTs generally provided good performance in freshwater (median ratios close to 1.0), but an inverse correlation with the increasing salinity was observed (median ratios 0.7 at the stations with salinity >5). The Lewatit FO 36 DGTs provided good performance in the salinity range 0–18 (median ratios 1.0). However, a strong negative influence was observed at stations with high salinity levels (>18, ratio 0.6) and during the long-term deployment in seawater (ratios <0.5 over deployment periods ≥2 days). The Dow-PIWBA and Diphonix DGTs provided overall similar results with excellent performances along the whole salinity gradient (median ratios 1.1 and 1.0, respectively). Nevertheless, the long-term deployment trial in seawater (salinity ∼27) revealed the robustness of Diphonix DGTs that provided outstanding results even after 28 days of deployment (ratio 1.0). The differences in the performance of tested DGT resins were mostly given by the changes of U speciation along the salinity gradient. The speciation modelling of U showed that calcium uranyl carbonate complexes dominate along the Scheldt estuary (from 97 to 86% seawards) with increasing fraction of UO 2 (CO 3) 3 4− (from 2 to 14%) towards the mouth. [Display omitted] • Comparative study of DGT resins for determination of uranium reveals their applicability in natural waters. • The Chelex-100 and Lewatit FO 36 are not suitable for application in seawater (salinity >5 and 18, respectively). • Dow-PIWBA and Diphonix provide excellent results in seawater (salinity ∼27). • Only Diphonix quantitatively accumulates uranium even after 28 days of deployment in seawater. • Uranium speciation along the salinity gradient has strong influence on the DGT performance. [ABSTRACT FROM AUTHOR]
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- 2022
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123. Developments in the diffusive gradients in thin-films technique for the speciation of oxyanions and platinum group elements in aquatic systems.
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Gao, Yue, Zhou, Chunyang, Galceran, Josep, Rey-Castro, Carlos, Puy, Jaume, Baeyens, Willy, and Leermakers, Martine
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PLATINUM group , *OXYANIONS , *CHEMICAL speciation , *TITANIUM oxides , *PASSIVE sampling devices (Environmental sampling) - Abstract
Diffusive Gradients in Thin-films (DGT) is an in situ passive sampler with a widespread use in environmental studies. Within the ample range of analytes that can be probed with DGT, this review focuses on oxyanions and platinum group elements (PGEs). Ferrihydrite, zirconia, titanium dioxide and thiol-functionalized silica solid phases have been typically used as binding agents in DGT devices for oxyanions. DGT for PGEs had to overcome challenging interference problems during IPC-MS measurement of eluates, as well as slow equilibration kinetics in the bulk solution after spiking. This review summarizes the most recent analytical advances concerning the development and application of DGT with these target element groups, and points to the remaining knowledge gaps. • Zirconia and titanium oxide based binding gels allow quantification of oxyanions. • Redox speciation of As, Cr, Sb and Se is possible using appropriate binding gels. • Fe oxide based binding gels are suited to bind several organic P compounds. • Agarose was the preferred diffusive gel in the DGT for PGEs accumulation. • Resins used for PGEs are Purolite S920 (isothioureum) and AG MP-1 (anion exchange). [ABSTRACT FROM AUTHOR]
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- 2022
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124. Mercury distribution, mobilization and bioavailability in polluted sediments of Scheldt Estuary and Belgian Coastal Zone.
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Ma T, Perrot V, Baeyens W, Li G, Lievens S, Ngo HTT, Nguyen TTT, Leermakers M, and Gao Y
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In this study, the vertical distribution of mercury (Hg) in estuarine and marine sediment porewaters and solid phases was assessed by conventional and passive sampling techniques in the historically polluted Scheldt Estuary and Belgian Coastal Zone (BCZ). The Diffusive Gradients in Thin-films (DGT) measured labile Hg concentrations (Hg
LA ) were mostly lower than the porewater Hg concentrations (HgPW ), and they also presented different vertical distribution patterns. Still high Hg concentrations in the sediment solid phases, comparable to the historical ones, were observed. Even though pH, redox potential and dissolved sulfide concentration could influence the Hg biogeochemical behaviour, organic matter (OM) played a key role in governing Hg mobilization from sediment solid phase to porewater and in its partitioning between porewater and solid phase over depth. In the marine sediments, where OM had a marine signature, higher labile Hg concentrations in the porewater and faster resupply from the solid phase were observed. The DGT technique showed significant potential not only for the measurement of bioavailable Hg fractions in porewater, but also for the assessment of kinetic parameters governing the release of labile Hg species from the solid phase with the assistance of the DGT Induced Fluxes in Sediments (DIFS) model., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Tianhui Ma reports financial support was provided by Research Foundation Flanders. Vincent Perrot reports financial support was provided by Research Foundation Flanders., (Copyright © 2023 Elsevier B.V. All rights reserved.)- Published
- 2024
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125. Phosphorus mobilization in sulfidic sediments in the Baltic Sea.
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Zhou C, Gao Y, Zhang H, Luo M, Ma T, Li G, Vandeputte D, Leermakers M, and Baeyens W
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It is well-known that the geochemical behavior of phosphorus (P) in sediments is closely related to that of Fe and Mn, but their relations remain unclear in long-term sulfidic sediments such as those of the Gotland Basin in the Baltic Sea. Therefore, P mobilization in these sediments at both shallow and deep sites was investigated in relation to that of Fe, Mn, and S. To achieve that aim, classic sediment slicing and subsequent solid phase sequential extraction were combined with in situ DGT (Diffusive Gradients in Thin-films) sampling, DIFS (DGT induced flux in sediments) modelling, and Visual MINTEQ calculations. Correlations between total dissolved and labile dissolved concentrations of P, Mn, and Fe in porewater, and the associations between labile fractions of these elements in the solid phase suggested two kinds of sources for P: The dissolution of P-bearing Fe oxides and/or Mn carbonates was observed in the shallower sites, while P and Mn release from different solid sources was observed in the deepest sites. Although the formation of Fe sulfides leads to extremely low dissolved Fe level in porewater, the simultaneous release of P with Mn/Fe was confirmed by theoretical calculations with Visual MINTEQ. The DIFS model showed that the resupply ability of P from sediment solids is determined by labile pool size. The application of experimental and theoretical methods made it possible to clarify the relationships between P, Fe, Mn and S in sulfidic sediments which may contribute to a better understanding of the P cycle in other sulfidic regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
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- 2024
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126. Microplastics (≤ 10 μm) bioaccumulation in marine sponges along the Moroccan Mediterranean coast: Insights into species-specific distribution and potential bioindication.
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Krikech I, Oliveri Conti G, Pulvirenti E, Rapisarda P, Castrogiovanni M, Maisano M, Le Pennec G, Leermakers M, Ferrante M, Cappello T, and Ezziyyani M
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- Animals, Microplastics analysis, Plastics, Ecosystem, Bioaccumulation, Environmental Monitoring, Water Pollutants, Chemical analysis, Porifera
- Abstract
Microplastics (MPs) are pervasive in marine environments and widely recognized as emerging environmental pollutants due to the multifaceted risks they exert on living organisms and ecosystems. Sponges (Phylum Porifera) are essential suspension-feeding organisms that may be highly susceptible to MPs uptake due to their global distribution, unique feeding behavior, and sedentary lifestyle. However, the role of sponges in MP research remains largely underexplored. In the present study, we investigate the presence and abundance of MPs (≤10 μm size) in four sponge species, namely Chondrosia reniformis, Ircinia variabilis, Petrosia ficiformis, and Sarcotragus spinosulus collected from four sites along the Mediterranean coast of Morocco, as well as their spatial distribution. MPs analysis was conducted using an innovative Italian patented extraction methodology coupled with SEM-EDX detection. Our findings reveal the presence of MPs in all collected sponge specimens, indicating a pollution rate of 100%. The abundance of MPs in the four sponge species ranged from 3.95×10
5 to 1.05×106 particles per gram dry weight of sponge tissue, with significant differences observed among sampling sites but no species-specific differences. These results imply that the uptake of MPs by sponges is likely influenced by aquatic environmental pollution rather than the sponge species themselves. The smallest and largest MPs were identified in C. reniformis and P. ficiformis, with median diameters of 1.84 μm and 2.57 μm, respectively. Overall, this study provides the first evidence and an important baseline for the ingestion of small MP particles in Mediterranean sponges, introducing the hypothesis that they may serve as valuable bioindicators of MP pollution in the near future., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interestsMargherita, Ferrante and Gea Oliveri Conti, have patent #International Application No. PCT/IB 2019/051,838 Italian patent n. 102018000003337–07 March 2018, European patent n.3788344 July 20, 2022 licensed to Italian Minister and EU patent office. No other conflict of interest is disclosed., (Copyright © 2023 Elsevier Inc. All rights reserved.)- Published
- 2023
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127. Assessment of 226 Ra and U colloidal transport in a mining environment.
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Reymond M, Descostes M, Besançon C, Leermakers M, Billon S, Cherfallot G, Muguet M, Beaucaire C, Smolikova V, and Patrier P
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- Kaolin, Water analysis, Environmental Monitoring methods, Barium Sulfate, Trace Elements analysis
- Abstract
The colloidal transport of trace (Fe, Al, Ba, Pb, Sr, U) and ultra-trace (
226 Ra) elements was studied in a mining environment. An original approach combining 0.45 μm filtered water sampling, the Diffusive Gradient in Thin films (DGT) technique, mineralogical characterization, and geochemical modelling was developed and tested at 17 sampling points. DGT was used for the truly dissolved fraction of the elements of interest, while the 0.45 μm filtration includes both colloidal and truly dissolved fractions (together referred to as total dissolved fraction). Results indicated a colloidal fraction for Al (up to 50%), Ba (up to 86%), and Fe (up to 99%) explained by the presence of submicrometric grains of kaolinite, barite, and ferrihydrite, respectively. Furthermore, the total dissolved226 Ra concentration in the water samples reached up to 10-25 Bq/L (1.2-3.0 10-12 mol/L) at 3 sampling points, while the truly dissolved aqueous226 Ra concentrations were in the mBq/L range. Such high total dissolved concentrations are explained by retention on colloidal barite, accounting for 95% of the total dissolved226 Ra concentration. The distribution of226 Ra between the truly dissolved and colloidal fractions was accurately reproduced using a (Rax ,Ba1-x )SO4 solid solution, with values of the Guggenheim parameter a0 close to ideality.226 Ra sorption on ferrihydrite and kaolinite, other minerals well known for their retention properties, could not explain the measured colloidal fractions despite their predominance. This illustrates the key role of barite in such environments. The measured concentrations of total dissolved U were very low at all the sampling points (<4.5 10-10 mol/L) and the colloidal fraction of U accounted for less than 65%. U sorption on ferrihydrite could account for the colloidal fraction. This original approach can be applied to other trace and ultra-trace elements to complement when necessary classical environmental surveys usually performed by filtration on 0.45 μm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2023
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128. Investigation on metal geochemical cycling in an anthropogenically impacted tidal river in Belgium.
- Author
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Ma T, Baeyens W, Leermakers M, Smolíková V, Luo M, Li G, Vandeputte D, Perrot V, and Gao Y
- Abstract
The geochemical behavior of metals in water and sediment was investigated in the tidal section of the Zenne River in Belgium. Twelve-hour sampling campaigns were performed in October 2013 and March 2021 at the mouth of the Zenne River, under dry and rainy weather conditions respectively. Water samples were collected every hour while the passive samplers of Diffusive Gradients in Thin-films (DGT) were deployed continuously during a tidal cycle. In addition, bottom sediments were sampled at the tidal station and water samples were taken upstream and downstream of that station to identify the metal sources. The highest concentrations of Fe, Mn, Pb, Cr, Ni and Zn appear at low tide, indicating the Zenner River as a main source. However, for Co, Cd and Cu, other sources including upstream transport may explain their behavior during a tidal cycle. Fe, Pb and Cr are essentially transported in the particulate phase (<10 % dissolved) while the other metals in the dissolved phase (20 to 90 %). Rainfall and wind gust events also play an important role in trace metal distribution, increasing sediment resuspension and metal desorption. A good agreement was found between the time-averaged dissolved and DGT-labile metal concentrations with the exception of Cu and Fe, which form strong organic Cu complexes and Fe colloids respectively. The sediments of the tidal Zenne are contaminated by trace metals, thus acting as a secondary pollution source to the river. The reductive dissolution of Mn and Fe oxyhydroxides and the release of associated trace metals are the main mobilization mechanisms. Knowledge of the upstream and downstream levels in the water column, the benthic fluxes, which are based on turbulent diffusion, and the partitioning between dissolved and particulate phases allow to explain the metal concentration variations during the tidal cycle., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2023
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129. Origin and partitioning of mercury in the polluted Scheldt Estuary and adjacent coastal zone.
- Author
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Perrot V, Ma T, Vandeputte D, Smolikova V, Bratkic A, Leermakers M, Baeyens W, and Gao Y
- Abstract
Estuaries and coastal zones are areas with complex biogeochemical and hydrological cycles and are generally facing intense pollution due to anthropogenic activities. An emblematic example is the Scheldt Estuary which ends up in the North Sea and has been historically heavily contaminated by multiple pollutants, including mercury (Hg). We report here Hg species and their levels in surface waters of the Scheldt Estuary and the Belgian Part of North Sea (BPNS) from different sampling campaigns in February-April 2020 and 2021. Along the estuary, Hg concentration on suspended particles ([Hg
SPM ]) progressively decreased with increasing salinity and was strongly correlated with organic matter content (%Corg ) and origin (identified with δ13 Corg ). While [HgSPM ] drives total Hg concentration in the estuary (total dissolved Hg, HgTD is only 7 ± 6 %), annual and daily variations of total Hg levels were mostly attributed to changes in SPM loads depending on river discharge and tidal regime. In the BPNS, a significant fraction of total Hg occurs as HgTD (40 ± 21 %) and the majority of this HgTD was reducible (i.e. labile Hg), meaning potentially available for microorganisms. Compared to the '90s, a significant decrease of [HgSPM ] was observed in the estuary, but this was not the case for [HgTD ], which can be due to (1) still significant discrete discharges from Antwerp industrial area, and (2) higher Hg partitioning towards the dissolved phase in the water column relative to the '90s. Our results highlight the important contribution of the Scheldt estuary for the Hg budget in North Sea coastal waters, as well as the need for seasonal monitoring of all Hg species., (Copyright © 2023 Elsevier B.V. All rights reserved.)- Published
- 2023
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130. Insights into bioaccumulation and bioconcentration of potentially toxic elements in marine sponges from the Northwestern Mediterranean coast of Morocco.
- Author
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Krikech I, Ranjbar Jafarabadi A, Leermakers M, Le Pennec G, Cappello T, and Ezziyyani M
- Subjects
- Animals, Bioaccumulation, Environmental Monitoring methods, Morocco, Risk Assessment, Seawater, Metals, Heavy analysis, Porifera, Soil Pollutants analysis
- Abstract
The present research aimed to investigate the concentrations and patterns of six potentially toxic elements (PTEs) in three common sponge species collected along the Moroccan Mediterranean coast, as well as their levels in ambient seawater and sediments. Distinct inter-species variability in PTEs bioaccumulation was observed among the three species, suggesting that sponges have distinct selectivity for assimilating PTEs from the surrounding environment. C. crambe had a higher enrichment capacity for Cu, As, Cr and Ni, while P. ficiformis and C. reniformis exhibited the highest concentration of Cd and Pb, respectively. Interestingly, a similar spatial distribution patterns of PTEs was observed in the three media, with high values occurring in Tangier and Al-Hoceima locations. Overall, our results confirm that sponges reliably reflect the bioavailability of PTEs in their immediate environment, especially C. crambe, whose PTE tissue contents were highly and positively correlated with the contents of all PTEs in the sediments., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
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131. Elimination of interferences in the determination of platinum, palladium and rhodium by diffusive gradients in thin films (DGT) and inductively coupled plasma mass spectrometry (ICP MS) using selective elution.
- Author
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Abdulbur-Alfakhoury E and Leermakers M
- Abstract
The analysis of platinum (Pt), palladium (Pd) and rhodium (Rh) in aquatic samples by the diffusive gradients in thin films (DGT) technique using chelating resins, specific designed for the accumulation of PGEs, namely Purolite S914, S920 and Italmatch Chemicals IONQUEST® MPX-317. may however, still be influenced by the accumulation of other elements such (Cu, Zn, Pb, etc.) which will be extracted simultaneously by the hot aqua regia extraction and interfere with the Inductively Coupled Plasma Mass Spectrometry (ICPMS) analysis of the Platinum Group Elements (PGEs). Selective extractions were investigated to release the interfering elements without loss of the Platinum Group Elements (PGEs) from the resin gels. . A rinse with deionized water removes over 95% of Sr and Rb and a second rinse with 0.05 mol L
-1 H2 SO4 can be used to as a common eluent to remove an important fraction of the interfering elements from S920 and S914 without loss of PGEs but this results in loss of around 15% of the PGEs from MPX-317. It was shown that selective extractions can be used to remove specific interferences from each resin gel., (Copyright © 2020 Elsevier B.V. All rights reserved.)- Published
- 2021
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132. Development of the diffusive gradients in thin films technique (DGT) for platinum (Pt), palladium (Pd), and rhodium (Rh) in natural waters.
- Author
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Abdulbur-Alfakhoury E, Van Zutphen S, and Leermakers M
- Abstract
The Diffusive Gradients in Thin Films (DGT) technique was developed for the first time for the platinum group elements (PGEs) platinum (Pt), palladium (Pd), and rhodium (Rh). Different chelating resins, specific designed for the accumulation of PGEs, namely Purolite S914, S920, S985, Italmatch Chemicals IONQUEST
® MPX-317 and MP-102, were compared. The method development involved several different steps: 1) selection of an appropriate diffusive gel, 2) comparison of resins for the PGEs in terms of kinetics of uptake, 3) development of an efficient elution method for the PGEs from the resin gel, 4) Determination of diffusion coefficients for the PGEs in the diffusive gel, 5) Investigation of the influence of pH, ionic strength and dissolved organic matter on the diffusion coefficients and 6) study the selectivity of the tested resins gels in terms of potential interferences on the determination by ICPMS. Pt, Pd and Rh showed a linear accumulation over time for all resins and diffusion coefficients were independent of pH. The diffusion coefficient for Pt increased with increasing ionic strength (>0.5 M NaCl), but not for Pd and Rh. The interference study showed that Sr was the most important interferent for Rh and Pd and must be removed prior to analysis. The resins Purolite S914, Purolite S920, and Italmatch Chemicals IONQUEST® MPX-317 showed the best performance in terms of detection limits and separation of interferences. Using optimized procedures, the concentrations of Pt, Pd and Rh can be quantified at pg L-1 levels in natural waters for a 14 day deployment time., (Copyright © 2019. Published by Elsevier B.V.)- Published
- 2019
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133. An alternative sequential extraction scheme for the determination of trace elements in ferrihydrite rich sediments.
- Author
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Leermakers M, Mbachou BE, Husson A, Lagneau V, and Descostes M
- Abstract
Sequential extraction schemes (SES) were evaluated to investigate the fractionation of Al, As, Cd, Cs, Cr, Co, Cu, Fe, Mn, Mo, Pb, Sr, U and Zn between the different mineral phases in iron oxide rich deposits of a former uranium mining site. Ineffective dissolution of iron oxide was observed when applying the BCR sequential extraction scheme. The hydroxylamine hydrochloride reagent in nitric acid could not effectively dissolve the iron oxide phase, even after several consecutive extractions. The use of sodium pyrophosphate to remove organic matter prior to the dissolution of the iron oxides and the use of oxalic acid buffer and dithionite citrate buffer to dissolve the amorphous and crystalline iron oxides was evaluated. An alternative six step SES for iron oxide rich sediments is proposed consisting of F1) Exchangeable-Carbonate fraction using acetic acid/ sodium acetate buffer (pH 5) F2) Labile organic fraction using sodium pyrophosphate, F3) Easily reducible amorphous oxides using an oxalic acid buffer, F4) Organic and Sulfide fraction using hydrogen peroxide, followed by ammonium acetate extraction, F5) Poorly reducible crystalline oxides using sodium dithionite and F6) residual fraction using a microwave digestion step with hydrofluoric acid, nitric acid and hydrochloride acid mixture. A good correspondence between the sum of the sequential extraction steps and total metal concentrations was found. Both the BCR method and new method were also applied to the CRM BCR 701 providing indicative values for non-certified elements with the BCR method and indicative values for the method presented., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
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134. Capping with activated carbon reduces nutrient fluxes, denitrification and meiofauna in contaminated sediments.
- Author
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Bonaglia S, Rämö R, Marzocchi U, Le Bouille L, Leermakers M, Nascimento FJA, and Gunnarsson JS
- Subjects
- Geologic Sediments, Nitrates, Nutrients, Charcoal, Denitrification
- Abstract
Sediment capping with activated carbon (AC) is an effective technique used in remediation of contaminated sediments, but the ecological effects on benthic microbial activity and meiofauna communities have been largely neglected. This study presents results from a 4-week experiment investigating the influence of two powdered AC materials (bituminous coal-based and coconut shell-derived) and one control material (clay) on biogeochemical processes and meiofauna in contaminated sediments. Capping with AC induced a 62-63% decrease in denitrification and a 66-87% decrease in dissimilatory nitrate reduction to ammonium (DNRA). Sediment porewater pH increased from 7.1 to 9.0 and 9.7 after addition of bituminous AC and biomass-derived AC, respectively. High pH (>8) persisted for at least two weeks in the bituminous AC and for at least 24 days in the coconut based AC, while capping with clay had no effect on pH. We observed a strong impact (nitrate fluxes being halved in presence of AC) on nitrification activity as nitrifiers are sensitive to high pH. This partly explains the significant decrease in nitrate reduction rates since denitrification was almost entirely coupled to nitrification. Total benthic metabolism estimated by sediment oxygen uptake was reduced by 30 and 43% in presence of bituminous coal-based AC and coconut shell-derived AC, respectively. Meiofauna abundances decreased by 60-62% in the AC treatments. Taken together, these observations suggest that AC amendments deplete natural organic carbon, intended as food, to heterotrophic benthic communities. Phosphate efflux was 91% lower in presence of bituminous AC compared to untreated sediment probably due to its content of aluminum (Al) oxides, which have high affinity for phosphate. This study demonstrates that capping with powdered AC produces significant effects on benthic biogeochemical fluxes, microbial processes and meiofauna abundances, which are likely due to an increase in porewater pH and to the sequestration of natural, sedimentary organic matter by AC particles., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
135. Olivine Dissolution in Seawater: Implications for CO 2 Sequestration through Enhanced Weathering in Coastal Environments.
- Author
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Montserrat F, Renforth P, Hartmann J, Leermakers M, Knops P, and Meysman FJ
- Subjects
- Carbonates, Seawater, Weather, Carbon Dioxide, Solubility
- Abstract
Enhanced weathering of (ultra)basic silicate rocks such as olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine weathering is expected to increase seawater alkalinity, thus resulting in additional CO
2 uptake from the atmosphere. However, the mechanisms of marine olivine weathering and its effect on seawater-carbonate chemistry remain poorly understood. Here, we present results from batch reaction experiments, in which forsteritic olivine was subjected to rotational agitation in different seawater media for periods of days to months. Olivine dissolution caused a significant increase in alkalinity of the seawater with a consequent DIC increase due to CO2 invasion, thus confirming viability of the basic concept of enhanced silicate weathering. However, our experiments also identified several important challenges with respect to the detailed quantification of the CO2 sequestration efficiency under field conditions, which include nonstoichiometric dissolution, potential pore water saturation in the seabed, and the potential occurrence of secondary reactions. Before enhanced weathering of olivine in coastal environments can be considered an option for realizing negative CO2 emissions for climate mitigation purposes, these aspects need further experimental assessment.- Published
- 2017
- Full Text
- View/download PDF
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