9 results on '"Leermakers, Martine"'
Search Results
2. Genetic diversity of the giant tiger prawn Penaeus monodon in relation to trace metal pollution at the Tanzanian coast.
- Author
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Rumisha, Cyrus, Leermakers, Martine, Elskens, Marc, Mdegela, Robinson H., Gwakisa, Paul, and Kochzius, Marc
- Subjects
PENAEUS monodon ,MARINE pollution ,HEAVY metal toxicology ,OCEAN - Abstract
The genetic diversity of giant tiger prawns in relation to trace metals (TMs) pollution was analysed using 159 individuals from eight sites at the Tanzanian coast. The seven microsatellites analysed showed high degree of polymorphism (4–44 alleles). The measured genetic diversity (H o = 0.592 ± 0.047) was comparable to that of populations in the Western Indian Ocean. Apart from that, correlation analysis revealed significant negative associations between genetic diversity and TMs pollution ( p < 0.05), supporting the genetic erosion hypothesis. Limited gene flow was indicated by a significant genetic differentiation (F ST = 0.059, p < 0.05). The Mantel test rejected the isolation-by-distance hypothesis, but revealed that gene flow along the Tanzanian coast is limited by TMs pollution. This suggests that TMs affect larvae settlement and it may account for the measured deficiency of heterozygosity. This calls for strengthened pollution control measures in order to conserve this commercially important species. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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3. Trace metals in the giant tiger prawn Penaeus monodon and mangrove sediments of the Tanzania coast: Is there a risk to marine fauna and public health?
- Author
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Rumisha, Cyrus, Mdegela, Robinson H., Kochzius, Marc, Leermakers, Martine, and Elskens, Marc
- Subjects
PENAEUS monodon ,MARINE animals ,TRACE metals ,WASTE treatment ,PUBLIC health - Abstract
Mangroves ecosystems support livelihood and economic activities of coastal communities in the tropics and subtropics. Previous reports have documented the inefficiency of waste treatment facilities in Tanzania to contain trace metals. Therefore, the rapidly expanding coastal population and industrial sector is likely to threaten mangrove ecosystems with metal pollution. This study analysed trace metals in 60 sediment samples and 160 giant tiger prawns from the Tanzanian coast in order to document the distribution of trace metals and to establish if measured levels present a threat to mangrove fauna and are of public health importance. High levels of Cr, Co, Cu, Fe, Mn, Ni, and V was observed in mangroves of river Pangani, Wami, and Rufiji. Multivariate analysis showed that they originate mainly from weathering and erosion in the river catchments. Extreme enrichment of Cd was observed in a mangrove affected by municipal sewage. The distribution of Hg, Pb, and Zn was related with urbanisation and industrial activities along the coast. The metal pollution index was high at Pangani, Saadani, and Rufiji, suggesting that these estuarine mangroves are also affected by human activities in the catchment. Moderate to considerable ecological risks were observed in all sampled mangroves, except for Kilwa Masoko. It was revealed that As, Cd, and Hg present moderate risks to fauna. High levels of Cu, Fe and Zn were observed in prawns but the level of the non-essential Cd, Hg, and Pb did not exceed the maximum allowed levels for human consumption. However, based on the trends of fish consumption in the country, weekly intake of Hg is likely to exceed provisional tolerable weekly intake level, especially in fishing communities. This calls for measures to control Hg emissions and to strengthen sewage and waste treatment in coastal cities and urban centres in the basin of major rivers. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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4. Novel speciation method based on Diffusive Gradients in Thin Films for in situ measurement of uranium in the vicinity of the former uranium mining sites.
- Author
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Drozdzak, Jagoda, Leermakers, Martine, Gao, Yue, Phrommavanh, Vannapha, and Descostes, Michael
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THIN films ,URANIUM mining ,ELUTION (Chromatography) ,IONIC strength ,GEOCHEMICAL cycles - Abstract
The Diffusive Gradients in Thin Films (DGT) technique using PIWBA resin (The Dow Chemical Company) was developed and validated for the measurement of uranium (U) concentration in natural and uranium mining influenced waters. The U uptake on the PIWBA resin gel was 97.3 ± 0.4% (batch method; V sol = 5 mL; [U] = 20 μg L −1 ; 0.01 M NaNO 3 ; pH = 7.0 ± 0.2). The optimal eluent was found to be HNO 3conc /70 °C with an elution efficiency of 88.9 ± 1.4%. The laboratory DGT investigation demonstrated that the PIWBA resin gel exhibits a very good performance across a wide range of pH (3–9) and ionic strength (0.001–0.7 M NaNO 3 ) at different time intervals. Neither effect of PO 4 3− (up to 1.72 × 10 −4 M), nor of HCO 3 − (up to 8.20 × 10 −3 M) on the quantitative measurement of uranium by DGT- PIWBA method were observed. Only at very high Ca 2+ (2.66 × 10 −4 M), and SO 4 2− (5.55 × 10 −4 M) concentration, the U uptake on DGT- PIWBA was appreciably lessened. In-situ DGT field evaluation was carried out in the vicinity of three former uranium mining sites in France (Loire-Atlantique and Herault departments), which employ different water treatment technologies and have different natural geochemical characteristics. There was a similar or inferior U uptake on DGT-Chelex ® -100 in comparison with the U accumulation on a DGT- PIWBA sampler. Most likely, the performance of Chelex ® -100 was negatively affected by a highly complex matrix of mining waters. The high concentration and identity of co-accumulating analytes, typical for the mining environment, did not have a substantial impact on the quantitative uptake of labile U species on DGT - PIWBA . The use of the polyphenol impregnated anion exchange resin leads to a significant advancement in the application and development of the DGT technique for determination of U in the vicinity of the former uranium mining sites. [ABSTRACT FROM AUTHOR]
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- 2016
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5. 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, Imad, Ranjbar Jafarabadi, Ali, Leermakers, Martine, Le Pennec, Gaël, Cappello, Tiziana, and Ezziyyani, Mohammed
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POISONS ,SPONGES (Invertebrates) ,BIOCONCENTRATION ,BIOACCUMULATION ,COASTS ,HEAVY metals - 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. [Display omitted] • Sponges from Mediterranean Morocco were assessed for PTE accumulation for the first time. • There are intra- and inter-species PTE variability among the studied sponges. • PTEs were significantly higher in all matrices from TNG and ALH locations than those from other sites. • BCFs and BSAFs results suggest a sponge bioaccumulation of PTEs from seawater rather than from the sediment • Among the PTEs, Cu, As and Cd exhibited the highest BCFs and BSAFs values in sponges. [ABSTRACT FROM AUTHOR]
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- 2022
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6. Trace metal pollution and its influence on the community structure of soft bottom molluscs in intertidal areas of the Dar es Salaam coast, Tanzania.
- Author
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Rumisha, Cyrus, Elskens, Marc, Leermakers, Martine, and Kochzius, Marc
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TRACE metals ,MARINE pollution ,MOLLUSKS ,MARINE sediments ,MONTE Carlo method ,BIOTIC communities ,GASTROPODA - Abstract
Abstract: The influence of trace metal pollution on the community structure of soft bottom molluscs was investigated in intertidal areas of the Dar es Salaam coast. Significant enrichment of As, Mn, Mo, Sb, and Zn in sediments was recorded. Redundancy analysis indicated that trace metal pollution contributed 68% of the variation in community structure. Monte Carlo permutation test showed that As and Sb contributed significantly to variation in species composition. T-value biplots and van Dobben circles showed that the gastropods Acteon fortis, Assiminea ovata, and Littoraria aberrans, were negatively affected by As and Sb, while the bivalve Semele radiata and the gastropod Conus litteratus were only negatively affected by As. Bioaccumulation of As, Cd, Cu, Mo and Zn occurred in the bivalve Mactra ovalina and the gastropod Polinices mammilla. This calls for regular monitoring and management measures. [Copyright &y& Elsevier]
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- 2012
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7. Links between bacterial communities in marine sediments and trace metal geochemistry as measured by in situ DET/DGT approaches.
- Author
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Gillan, David C., Baeyens, Willy, Bechara, Rafeh, Billon, Gabriel, Denis, Kevin, Grosjean, Philippe, Leermakers, Martine, Lesven, Ludovic, Pede, Annelies, Sabbe, Koen, and Gao, Yue
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GEOCHEMISTRY ,MICROBIAL ecology ,TRACE metals -- Environmental aspects ,MICRONUTRIENTS ,BACTERIAL diversity ,STATISTICAL correlation ,SEDIMENTS ,SOIL remediation ,AQUATIC microbiology - Abstract
Abstract: Our current view about the relationship between metals and bacteria in marine sediments might be biased because most studies only use ex situ approaches to quantify metals. The aim of the present research was to compare ex situ and in situ methods of metal measurement (DET and DGT – diffusive equilibration or diffusive gradients in thin-films) and relate the results with two commonly used microbiological variables (bacterial biomass and bacterial diversity as revealed by DGGE). No previous studies have used such in situ approaches in microbial ecology. For biomass and most of the investigated trace metals (Ag, Cd, Sn, Cr, Ni, Cu, Pb, and Al) no significant correlations were found. The exceptions were Fe, Mn, Co, and As which behave like micronutrients. For bacterial diversity, no relevant relationships were found. We conclude that in situ methods are more adapted tools for microbial ecologists but that ex situ approaches are still necessary. [Copyright &y& Elsevier]
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- 2012
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8. Response of diffusive equilibrium in thin films (DET) and diffusive gradients in thin films (DGT) trace metal profiles in sediments to phytodetritus mineralisation
- Author
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Gao, Yue, Leermakers, Martine, Pede, Annelies, Magnier, Aurelie, Sabbe, Koen, Lourino Cabana, Beatriz, Billon, Gabriel, Baeyens, Willy, and Gillan, David C.
- Abstract
Environmental contextContaminated sediments can have a large and lasting effect on marine ecosystems. It was discovered that significant amounts of pollutants, especially arsenic, were released from contaminated sediments during a phytoplankton bloom in the Belgian Continental Zone. Once released to the water column, these pollutants can accumulate up marine food chains and be a source of contaminants to humans. AbstractField data from the Belgian Continental Zone showed elevated trace metal concentrations at the sediment–water interface after the occurrence of a phytoplankton bloom. In the present study, laboratory incubation experiments were used to investigate the effect of the phytodetritus remineralisation process on the release of trace metals from contaminated muddy sediments. This remineralisation process was followed by the measurement of chlorophyll-a and dissolved organic carbon levels in the top sediment layers. Two gel techniques, diffusive equilibrium in thin films (DET) and diffusive gradients in thin films (DGT), were used to assess vertical metal profiles in the sediment pore waters and to calculate the metal effluxes. These metal effluxes compared very well with the trace metal concentration variations in the overlying water of the sediment. Much higher effluxes of Mn, Co and As were observed after 2 days of incubation in the microcosms which received additions of phytodetritus. This trend gradually decreased after 7 days of incubation, suggesting that the elevated efflux of trace metals was proportional to the quantity of phytodetritus mineralised at the sediment–water interface. The release of large amounts of toxic elements from the sediments after phytoplankton blooms can therefore potentially affect the marine ecosystem in the Belgian Continental Zone.
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- 2012
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9. Speciation in Environmental Samples
- Author
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Baeyens, Willy, De Gieter, Marjan, Leermakers, Martine, and Windal, Isabelle
- Abstract
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
- Published
- 2007
- Full Text
- View/download PDF
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