Metal reference values established in Brazilian legislation for terrestrial disposal of dredged sediments and soil quality were derived for temperate regions. To evaluate the adequacy of such metal reference values to tropical soils, the ecotoxicity of a dredged sediment (from the Guanabara bay, Rio de Janeiro, Brazil) was investigated in two local soils (ferralsol and chernosol) by performing avoidance and reproduction tests using Folsomia candida and Enchytraeus crypticus. Test doses consisted of 0 %, 1.25 %, 2.5 %, 5, 10 %, and 20 %. Total and potentially bioavailable metal concentrations were determined in the test mixtures. Although the chernosol mixtures had the highest total metal concentrations, the influence of the expansive clay minerals (with high ability to adsorb metals) and the high contents of nutrients typical from this type of soils, seem to reduce the ecotoxicity. Collembolan avoidance behavior was the least sensitive endpoint. The lowest sediment doses increased the reproduction of F. candida in ferralsol mixtures. E. crypticus reproduction in the ferralsol mixtures were more pronounced at lower concentrations than in chernosol mixtures. Possibly the low nutrient content of the ferralsols, in connection with the addition of small amounts of sediment, created particular conditions that promoted reproduction of the test species. Data obtained in the ecotoxicological tests may support the establishment of a "safe" ecological dose of dredged sediments to be applied in tropical soils, supporting decision-makers in programs of environmental management.
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http://dx.doi.org/10.1007/s11356-014-3559-3 | DOI Listing |
Heliyon
January 2025
Instituto Nacional de Limnología (CONICET-UNL), Ciudad Universitaria Pje. El Pozo s/n Santa Fe, CP 3000, Argentina.
Alterations caused by human activities in the environment, such as dredging, modify the physicochemical conditions and affect the habitat. Maintenance dredging that allows large vessels access to inland ports is a recurring disruptive action. The study aimed to evaluate, during a maintenance dredging operation in a port area of the Paraná River, the modifications in the structure of the river, the presence of contaminants and bacterial organisms.
View Article and Find Full Text PDFEnviron Pollut
January 2025
Federal Institute of Maranhão, Campus Barreirinhas, Rodovia MA-225, KM 04, CEP:65590-000, Barreirinhas, Maranhão, Brazil.
Dredging in estuarine systems significantly impacts phytoplankton communities, with suspended particulate matter (SPM) and dissolved aluminum (Al) serving as indicators of disturbance intensity. This study assessed the effects of dredging in the São Marcos Estuarine Complex (SMEC), Brazil, over three distinct events (2015, 2017, 2020), involving varying sediment volumes and climatic influences. Prolonged dredging operations and increased sediment volumes led to a pronounced 43.
View Article and Find Full Text PDFSci Total Environ
January 2025
Laboratory of Coastal Biology and Microplastic Analysis, Department of Chemistry, Federal University of Espírito Santo, Brazil.
Several methods can be used to mitigate coastal erosion, and one of the leading solutions is known as beach nourishment (BN), which involves using dredged material for nourishment, adding sand to extend an eroding beach. Although it has many advantages, the environmental impacts of BN remain poorly understood, especially on plastic pollution, which had not been investigated until this study. We aimed to compare the abundance and distribution of microplastics (MPs) found in intertidal sediments and specimens of the bivalve mollusks Crassostrea brasiliana, Mytella strigata, Perna perna, and Tivela mactroides, collected in two beaches of Vitoria, Southeast of Brazil (da Costa et al.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
I2M (Institut de Mécanique et d'Ingénierie), UMR 5295, CNRS, University of Bordeaux, 33400 Talence, France.
From both economic and environmental points of view, the reuse of dredged sediments in the direct onsite casting of concrete represents a promising method for replacing sand. The aim of this study was to develop a cementitious material that (i) reuses the thin particles of sediments; (ii) has a low density due to the incorporation of air foam in the material; and (iii) achieves a minimum mechanical strength of 0.5 MPa for embankment applications.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29, Prague 6, Czech Republic.
Human activities result in sediment accumulation, so the reservoirs gradually lose their functionality, impacting their ability to manage large flood inflows, supply water, and generate hydroelectric power. Therefore, periodic removal of sediments from water reservoirs is essential to maintain functionality. Notwithstanding, the management of dredged sediments is a multifaceted process that involves careful consideration of environmental, regulatory, and economic factors to ensure their responsibility and sustainable handling.
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