Publicações 2024

Amazon, Honey, Bee, Fish, Mercury hair, Riverside Community, Bioaccumulation, Biomagnification, Riparian ecosystems, Neotropical, Savanna, Floodplain, Araguaia River, Central Brazil, Uptake, Biomonitoring, Indicator kriging, Spatial dependence, Paspalum repens, Cerrado


Mercury Bioconcentration and Translocation in Rooted Macrophytes (Paspalum repens Berg.) from Floodplain Lakes in the Araguaia River Watershed, Brazilian Savanna

Lucas Cabrera Monteiro, Ludgero Cardoso Galli Vieira, José Vicente Elias Bernardi, Ygor Oliveira Sarmento Rodrigues, Lígia Pereira Borges de Mesquita, João Pedro Rudrigues de Souza, Guilherme Sena, Iuri Aparecida da Silva Oliveira, Cássio da Silva Cabral, José Francisco Gonçalves Júnior, Jurandir Rodrigues de Souza and Wanderley Rodrigues Bastos

Abstract: Macrophytes are fundamental photosynthetic organisms for functioning freshwater ecosystems, identified as potential bioindicators of mercury (Hg) in the environment. We quantified the concentrations of total Hg (THg) in water and macrophytes (Paspalum repens Berg.) from 17 lakes on the Araguaia River floodplain, aiming to compare the bioconcentration factor (BCF) in the aerial tissues and roots; evaluate the translocation factor (TF) between plant tissues; and assess the influence of environmental factors and land use on THg concentrations in water and macrophytes. The BCF was significantly higher in roots (1.29 ± 0.32) than in aerial tissues (0.41 ± 0.34), with low TF between plant tissues (0.14 ± 0.06). The highest concentrations of THg in water were determined in lakes with higher land use intensity and a pH close to neutral, indicating the transport of particulate-bound Hg and the immobilization in the water column. In contrast, wetlands were priority areas for the bioconcentration of THg in macrophytes, associated with sulfate, dissolved oxygen, and oxidation–reduction potential in the water. Thus, although P. repens is not a suitable bioindicator of Hg mobilization by anthropogenic land use in our study area, our results suggest the potential of macrophytes as bioindicators of sites that are favorable to Hg methylation.

Mercury distribution, bioaccumulation, and biomagnification in riparian ecosystems from a Neotropical savanna floodplain, Araguaia River, Central Brazil

Lucas Cabrera Monteiro, Ludgero Cardoso Galli Vieira, José Vicente Elias Bernardi, Maria Cristina Nery do Nascimento Recktenvald, Adriely Ferreira da Costa Nery, Iara Oliveira Fernandes, Vinicius Lima de Miranda, Dulce Maria Sucena da Rocha, Ronaldo de Almeida e Wanderley Rodrigues Bastos

Abstract Summary Mercury distribution
Abstract Summary Mercury distribution

Graphical Abstract

Abstract: Litterfall is the main source of dry deposition of mercury (Hg) into the soil in forest ecosystems. The accumulation of Hg in soil and litter suggests the possibility of transfer to terrestrial vertebrates through environmental exposure or ingestion of plant tissues. We quantified total mercury (THg) concentrations in two soil layers (organic: 0 - 0.2 m; mineral: 0.8 - 1 m), litter, fresh leaves, and terrestrial invertebrates of the Araguaia River floodplain, aiming to evaluate the THg distribution among terrestrial compartments, bioaccumulation in invertebrates, and the factors influencing THg concentrations in soil and invertebrates. The mean THg concentrations were significantly different between the compartments evaluated, being higher in organic soil compared to mineral soil, and higher in litter compared to mineral soil and fresh leaves. Soil organic matter content was positively related to THg concentration in this compartment. The order Araneae showed significantly higher Hg concentrations among the most abundant invertebrate taxa. The higher Hg concentrations in Araneae were positively influenced by the concentrations determined in litter and individuals of the order Hymenoptera, confirming the process of biomagnification in the terrestrial trophic chain. In contrast, the THg concentrations in Coleoptera, Orthoptera and Hymenoptera were not significantly related to the concentrations determined in the soil, litter and fresh leaves. Our results showed the importance of organic matter for the immobilization of THg in the soil and indicated the process of biomagnification in the terrestrial food web, providing insights for future studies on the environmental distribution of Hg in floodplains.

Local and landscape factors influencing mercury distribution in water, bottom sediment, and biota from lakes of the Araguaia River floodplain, Central Brazil

Lucas Cabrera Monteiro, Ludgero Cardoso Galli Vieira, José Vicente Elias Bernardi, Wanderley Rodrigues Bastos, João Pedro Rudrigues de Souza, Maria Cristina Nery do Nascimento Recktenvald, Adriely Ferreira da Costa Nery, Iuri Aparecida da Silva Oliveira, Cássio da Silva Cabral d, Lilian de Castro Moraes, Cleber Lopes Filomeno, Jurandir Rodrigues de Souza

Graphical Abstract

Abstract: Mercury (Hg) is a chemical element widely present in the Earth’s crust. However, its high toxicity and ability to accumulate in organisms and biomagnify through food chains characterize it as a global pollutant of primary control. We assessed total mercury concentrations ([THg]) in abiotic and biotic compartments from 98 floodplain lakes associated with the Araguaia River and six tributaries (Midwest Brazil). [THg] quantification in water was performed by cold vapor atomic fluorescence spectroscopy. [THg] in bottom sediment was assessed using cold vapor generation atomic absorption spectrophotometry, while [THg] in macrophyte, periphyton, and plankton were quantified by thermal decomposition atomic absorption spectrometry. Hotspots of [THg] in water, bottom sediment, and macrophytes were determined in areas impacted by pasture and urban areas. In contrast, hotspots of [THg] in periphyton and forest fires were determined in preserved areas downstream. [THg] in plankton did not show a clear spatial distribution pattern. The mean bioaccumulation factor order was plankton (2.3 ± 1.8) > periphyton (1.3 ± 0.9) > macrophytes (0.7 ± 0.4) (KW = 55.09, p < 0.0001). Higher [THg] in water and bottom sediment were associated with high pH (R²adj = 0.118, p = 0.004) and organic matter (R²adj = 0.244, p < 0.0001). [THg] in macrophytes were positively influenced by [THg] in water (R²adj = 0.063, p = 0.024) and sediment (R²adj = 0.105, p = 0.007). [THg] in periphyton are positively related to forest fires (R²adj = 0.156, p = 0.009) and [THg] in macrophytes (R²adj = 0.061, p = 0.03) and negatively related to lake depth (R2adj = 0.045, p = 0.02). The transfer of Hg from water and sediment to the biota is limited. However, the progressive increase of the bio­ accumulation factor between macrophyte, periphyton, and plankton may indicate Hg biomagnification along the food chain of the Araguaia River floodplain.

Mercury in honey of stingless bee species from Brazil’s south, southeast and north (Amazon) regions

Natália A. Campos, Gabriel H.A. Holanda, Maria C.N.N. Recktenvald, Walkimar A. Costa-Júnior, Ludimilla Ronqui, Rejane S. Parpinelli, Josiel D. Froelich, Wanderley R. Bastos and Débora F. Oliveira

Graphical Abstract

Abstract: Food produced in regions with intense industrial or mining activity can be contaminated with heavy metals, including mercury (Hg). Human exposure to this metal can cause serious health problems. The aim of this study was to quantify and compare the levels of total Hg (THg) in samples of honey (n=44) produced by five species of stingless bees, as well as to compare the THg values among the collection regions. Samples were obtained from three Brazilian states, one each in the South, Southeast and North regions (respectively Paraná, São Paulo and Rondônia, the last in the Amazon rainforest). The average THg level in the honey samples was 0.00060⁻¹. The results also indicated a significant difference among the collection places. The high variability of the THg values in the honey samples might have been related to the territory foraged by the bees and the types of plants visited, but not the species or their behavior. The divergence among the average levels found for the different collection areas could have been a reflection of the types of predominant industrial activities in the analyzed regions.

A 35-Year Record (1987–2022) of Hg Concentrations in Two of the Fish Species Most Consumed by People Living in the Upper Madeira River Basin, Brazilian Amazon Region

Luiz Drude de Lacerda, Ronaldo de Almeida and Wanderley Rodrigues Bastos

Abstract: This study presents a 35-year record of total mercury (Hg) concentrations in the detritivore fish Prochilodus nigricans (Curimatã) and the carnivore Cichla pleiozona (Tucunaré), two of the most widely distributed, ecologically important and consumed fish species in the upper Madeira River Basin in the Western Brazilian Amazon. Fish samples from the major Madeira River and marginal lakes and tributaries were compared. Irrespective of site, Hg concentrations were higher in the carnivore fish compared to the detritivore. Hg concentrations increased 5-fold in C. pleiozona in the past three decades, whereas they remained relatively constant in P. nigricans when analyzing the entire 35-year period. When analyzed separately, fish in the main river and marginal lake and tributaries presented the same pattern of Hg variation, with a significant increase in Hg concentrations in the carnivore and in the detritivore in marginal lakes and tributaries but not in the main river. This was in line with the increase in methyl-Hg production in tributaries, mostly associated with deforestation in the past decade in the basin. Although an increase in direct emissions from artisanal gold mining also occurred in the past decade, this caused virtually no impact on fish Hg concentrations, suggesting atmospheric emission and deposition in forests and further export to water systems as an intermediate link with fish Hg concentrations.

Mercury in Fish and Human Hair and Estimated Dietary Intake in a Riverside Community of the Madeira River Basin in the Brazilian Amazon

Thayson Araujo Canela, Lucas Cabrera Monteiro, Cássio da Silva Cabral, Fábio da Silva Ximenes, Iuri Aparecida da Silva Oliveira, José Vicente Elias Bernardi, Ronaldo de Almeida and Wanderley Rodrigues Bastos

Abstract: Mercury (Hg) is a chemical element that poses risks to human health due to its high toxicity and environmental persistence. We determined the total Hg (THg) and methyl Hg (MeHg) concentrations in hair samples from residents of the Demarcação District (Porto Velho, Rondônia) in the Brazilian Amazon, as well as in water and fish samples, to evaluate factors influencing human exposure. The average THg concentration in human hair was 7.86 ± 6.78 mg kg⁻¹ and it was significantly higher in men, with an increasing trend related to age. There was no significant difference between female age groups. Human exposure to Hg through water was negligible compared to fish consumption. The average weekly intake estimates in the community varied between 1.54 and 4.62 µ kg⁻¹, substantially higher than the recommended limit. The fish species with the highest amounts safe for daily consumption were herbivores and detritivores. Our results contribute to an understanding of how exposure to Hg affects the health of riverside populations and provide insights for new research to develop methods to mitigate such exposure and thus improve the quality of life of Amazonian people.

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