Metal mobility after resuspension of contaminated sediments from a tropical urban bay Ana Paula De Castro Rodrigues, Christiane do Nascimento Monte, Gustavo Filgueira, Alexandre De Freitas, Bernardo Braz, et al. Revista Brasileira De Geografia Fisica, 2024 Dredging activities are recurrent in coastal cities, however, they can cause the remobilization of contaminants, increasing the risk to the biota. Guanabara Bay is a complex eutrophic estuary that undergoes dredging in several areas during the year. The Meriti River estuary is silted up and highly contaminated by metals, such as Cr, Cu, and Zn, due to the discharge of untreated sewage. In this sense, the present study aims to evaluate the remobilization of metals in the sediment (Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and bioavailability after resuspension. Twelve sampling points were collected along 4 transects. The resuspension experiments were performed at two intervals: 1 h (T1) and 24 h (T2) and followed protocols from previous studies. In general, all metals are remobilized after resuspension. - In addition, the bioavailability change (BC) index was applied., which showed 54% remobilization of Cr after T2. The transects closer to the river showed less remobilization after resuspension, which may be related to the saline gradient. Zn was the only metal that exceeded CONAMA Resolution 454/12 level 2 after resuspension, indicating a significant anthropogenic input to the area. Although organic matter (OM) is one of the main regulators of bioavailability in this study, the results suggest that there is an interference of bacterial activity in the dynamics of OM degradation, which directly impacts the bioavailability of metals after resuspension.
Potential toxicity of iron ore tailings after the overflow of a mining dam in Nova Lima (Minas Gerais State, Brazil) Ricardo Gonçalves César, Carmen Migueles, Pedro Zanetti, Lara Filgueira, Gustavo Koifmann, et al. Revista Brasileira De Geografia Fisica, 2024 In January 2022, the Pau Branco Mine dam in Nova Lima (MG), under the responsibility of Vallourec, overflowed after intense rainfall and iron ore tailings impacted surrounding soils and aquatic ecosystems. These tailings can alter the natural composition of soils and rivers, poising risks on soil biota. This study consists of a preliminary evaluation of potential toxicity of terrigenous materials impacted by tailings from the Pau Branco Mine, based on acute bioassays with earthworms (Eisenia andrei) and germination tests with lettuce (Lactuca sativa). The physical and chemical characterization and determination of toxic metals in the samples supported the interpretation of the ecotoxicological data. The results indicated that the tailing deposition induced the increase in particle density, due to the increase in iron concentrations in the samples. As a consequence, the water holding capacity (WHC) of the materials and organic matter concentrations were dramatically reduced. Given that the mining tailings exhibit fine texture, their depositions on soils increased the percentage of fines particles (silt) in the samples. Metal determination revealed geochemical anomalies for nickel, copper and chromium, whose concentrations exceeded the threshold limits defined by Brazilian law for soil and aquatic sediment quality. The bioassays with earthworms showed no significant earthworm mortality, indicating low acute toxicity. However, earthworm biomass was significantly reduced, suggesting that they were submitted to some stress induced by the exposure to contaminants and/or by the reduction of the organic matter contents (food scarcity) and WHC (water scarcity). The bioassays with lettuce showed no significant effects on germination levels. However, the seedling biomass was significantly reduced due, possibly, to the reduction of WHC and especially due to the increase of fines particles in the samples, which tends to inhibit the establishment of the root systems.
Change in water quality in an Amazonian microbasin: ecological and human health implications Louisiane Farias Batista, Thiago Shinaigger Rocha do Nascimento, Igor Costa, Edinelson Saldanha Correa, Christiane do Nascimento Monte Journal of Water and Health, 2024 The decline in the quality of water resources in the Amazon is very rapid in cities suffering from unplanned urban growth. The region has two defined seasons, winter (wet) and summer (dry), which directly affect the behavior of contaminants in aquatic ecosystems. The aim of this study was to assess the ecological and human health risks associated with the use of the watershed. In addition, an ecological index was proposed: the Quality Index for Aquatic Life, for the risk of contaminants to aquatic life. Sampling was carried out at six points in the Juá watershed. Physicochemical parameters, major anions, metals and total phosphorus were analyzed at both stations between 2020 and 2021. The highest concentrations of contaminants were found in the rainy season, due to the washing away of the banks. In this sense, Cl presented a concentration more than 307 times higher than that permitted by Brazilian legislation (wet). The ecological index showed that the watershed has a high risk of metals such as Cr III and Cr VI for the biota. The human health risk analysis showed a low risk; however, the lack of basic sanitation in the city indicates that monitoring of urban water resources is necessary.
Geochemical analysis of sediments from an urban microbasin in the amazon region Igor Costa, Thiago Shinaigger Rocha Nascimento, Louisiane Farias Batista, Edinelson Saldanha Correa, Christiane do Nascimento Monte Revista Brasileira De Geografia Fisica, 2024 A microbacia do igarapé do Irurá pertence a bacia hidrográfica do Rio Tapajós, e está localizada na cidade de Santarém- PA, no Oeste do Pará. A cidade, não possui uma rede de saneamento básico adequado, que faz com que boa parte do esgoto doméstico e industrial seja lançado in natura, em igarapés e no rio Tapajós, afetando diretamente as condições da biota aquática, como o pescado, que é parte da dieta alimentar e renda da região. O objetivo desta pesquisa foi a caracterização geoquímica dos sedimentos superficiais da microbacia do igarapé do Irurá. As coletas de sedimentos foram realizadas em cinco pontos amostrais, desde a nascente do igarapé Irurá até próximo à foz, entre os anos de 2020 e 2021. Foram mensurados parâmetros físico-químicos, como: pH em Água e em cloreto de Potássio (KCl), acidez potencial, capacidade de troca de cátions (CTC), soma de bases (SB), saturação em bases (V), matéria orgânica (M.O), sulfato, fósforo total (PT), metais (Al,Cr, Cu, Fe, , Mn e Zn). Foi aplicado o teste estatístico de Análise de Principal de Componente (APC). Os resultados mostraram que a textura do sedimento foi caracterizada por arenosa, além disso, as concentrações dos contaminantes foram maiores na estação seca. A APC mostrou correlações diferentes entre seca e chuva, o que pode estar relacionado à sazonalidade. As maiores concentrações de contaminantes na estação seca, indica que pode ter uma transferência dos contaminantes para a coluna d’água, devido aos processos naturais de ressuspensão do sedimento, o que aumenta o risco para biota aquática. Diante disso, é necessário que ampliem os estudos sobre a contaminação de recursos aquáticos amazônicos, principalmente, em áreas urbanas, onde a taxa de degradação dos recursos hídricos é mais rápida.
Bioavailability Assessment of Metals from the Coastal Sediments of Tropical Estuaries Based on Acid-Volatile Sulfide and Simultaneously Extracted Metals Ana Paula de Castro Rodrigues, Matheus Marinho Pereira, Aline Campos, Tássia Lins da Silva Quaresma, Rodrigo Pova, et al. Coasts, 2023 Bioavailability assessment is important for evaluating the risks to the local biota, and the combined use of several ecological risk indices in eutrophic environments allows the best analysis of the local reality for decision-making. The relationship between acid volatile sulfide (AVS) concentrations and simultaneously extracted metals (SEM) allows us to infer the metal holding capacity of sediment, with the objective of evaluating the potential bioavailability of trace metals (Cd, Cu, Ni, Pb, and Zn) using ecological risk indices, such as the ΣSEM/AVS model and Adverse Effect Index (AEI), in surface sediments from Guanabara Bay and Sepetiba Bay, Brazil. AVS was determined using a colorimetric method and SEM with ICP-OES. In general, almost all sampling in Sepetiba Bay showed ΣSEM/AVS ratio values above 1. However, all results for the ΣSEM/AVS ratio found for the Guanabara Bay sediments were <1 for both estuaries. After normalization by organic carbon content, a possible toxicity risk for biota was found in Sepetiba Bay. However, the AEI in Guanabara Bay was above 1 for all metals in most samples, also indicating a risk to the biota.
Potential toxicity of dredged sediments from sepetiba and guanabara bays (Rj) in scenario of disposal in ferralsols Aline Ribeiro Lessa FERREIRA, Ricardo Gonçalves CESAR, Danielle Martins de SIQUEIRA, Ana Paula de Castro RODRIGUES, Mariana VEZZONE, et al. Geociencias, 2020 O descarte indiscriminado de efluentes domésticos e industriais tem degradado ecossistemas estuarinos do Estado do RJ. Ações de dragagem são comumente requeridas para recuperação destes ambientes, tornando importante a avaliação dos impactos associados à disposição terrestre de materiais dragados. O presente estudo trata da avaliação do potencial tóxico de sedimentos dragados da foz do saco do Engenho, do Canal de São Francisco (Baía de Sepetiba, RJ) e do Rio Meriti (Baía de Guanabara, RJ), em cenário de disposição em Latossolo. As concentrações de metais pesados nos sedimentos foram determinadas por ICP-OES, sendo também estimados os fatores de enriquecimento (FE). As doses de sedimento aplicadas ao solo variaram entre 0 e 40%, onde 0% = Latossolo puro. Bioensaios agudos com minhocas (Eisenia andrei) foram realizados nas misturas solo:sedimento conforme protocolo padrão (ASTM). A dose letal de sedimento a 50% dos organismos (CL50), expressa em % de sedimento adicionada ao solo, foi estimada através da análise de PriProbit. As concentrações de metais nos sedimentos estavam acima dos valores orientadores do CONAMA para disposição destes materiais em água e em solo, com exceção do sedimento do canal de São Francisco, cujos teores de metais estavam em conformidade para disposição em solo. O sedimento que mostrou maior toxicidade foi o oriundo do Saco do Engenho (CL50 = 13,06%), seguido da foz do Rio Meriti (CL50 = 14,60%) e do Canal de São Francisco (CL50 = 28,02%). Estes dados concordam com as crescentes concentrações de metais determinadas para estes materiais, sendo maiores para o sedimento do Saco do Engenho, seguido do Rio Meriti e do Canal de São Francisco. Além disso, os FEs de metais nos sedimentos do Saco do Engenho e na foz do Rio Meriti indicam a ocorrência de fontes antrópicas importantes de metais pesados para estas áreas. Por fim, os sedimentos dragados foram tóxicos às minhocas, e os valores orientadores da legislação precisam ser revistos à luz das propriedades das principais ocorrências pedológicas brasileiras.
Environmental risk in a coastal zone of Rio de Janeiro state (Brazil) due to dredging activities Ecotoxicology in Latin America, 2017
Ecotoxicological assessment of dredged sediments from Guanabara and Sepetiba Bays (Rio de Janeiro, Brazil) using bioassays with earthworms Ecotoxicology in Latin America, 2017
