Publications by authors named "Giseli S Rocha"

The semiconductor copper tungstate (CuWO) may end up in aquatic ecosystems since it has the potential for water decontamination. The toxic effects of CuWO are totally unknown for eukaryotic organisms. In view of this, we aimed to evaluate the toxicity of CuWO particles (size of 161.

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Innovative applications of cobalt tungstate nanoparticles (CoWO NPs) are directly linked to their increased production and consumption, which can consequently increase their release into aquatic ecosystems and the exposure of organisms. Microalgae are autotrophic organisms that contribute directly to global primary productivity and provide oxygen for maintaining many organisms on Earth. In this paper, we assessed the toxicity of CoWO NPs when in contact with the freshwater microalga Raphidocelis subcapitata (Chlorophyceae).

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Among the vast array of functional nanoparticles (NPs) under development, nickel tungstate (NiWO) has gained prominence due to its potential applications as a catalyst, sensor, and in the development of supercapacitors. Consequently, new studies on the environmental impact of this material must be conducted to establish a regulatory framework for its management. This work aims to assess the effects of NiWO (NPs) on multiple endpoints (e.

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It is crucial to investigate the effects of mixtures of contaminants on aquatic organisms, because they reflect what occurs in the environment. Cadmium (Cd) and nickel (Ni) are metals that co-occur in aquatic ecosystems, and information is scarce on their joint toxicity to Chlorophyceae using multiple endpoints. We evaluated the effects of isolated and combined Cd and Ni metals on multiple endpoints of the chlorophycean Raphidocelis subcapitata.

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Article Synopsis
  • ZnWO nanoparticles (ZnWO-NPs) are used in various applications like sensors, lasers, and batteries, but their effects on aquatic ecosystems remain unclear.
  • This study is the first to assess the toxicity of ZnWO-NPs on the green microalga Raphidocelis subcapitata, revealing growth inhibition and changes in photosynthesis at specific concentrations.
  • The findings indicate that high levels of ZnWO-NPs can disrupt biochemical processes in microalgae, which could have broader implications for aquatic food chains and ecosystem health.
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In the environment, algae are exposed to several stressors such as limitation of essential nutrients and excess of toxic substances. It is well known the importance of phosphorus (P) supply for healthy metabolism of algae and impacts at this level can affect the whole aquatic trophic chain. Aluminum (Al) is the most abundant metal on Earth and it is toxic to different trophic levels.

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Aquatic organisms are exposed to several compounds that occur in mixtures in the environment. Thus, it is important to investigate their impacts on organisms because these combined effects can be potentiated. Cobalt (Co) and nickel (Ni) are metals that occur in the environment and are used in human activities.

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Metal discharges in aquatic ecosystems are of concern since they affect different trophic levels, altering the functioning of the aquatic food chain. The metals can interact among them and with other pollutants, resulting in complex mixtures whose effects on biota are unpredictable. The impacts of copper (Cu) and cadmium (Cd), isolated and combined, on the freshwater copepod Notodiaptomus iheringi were assessed in acute and sub-chronic exposures.

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Phosphorus (P; macronutrient) and cobalt (Co; micronutrient) are essential for algal healthy metabolism. While P provides energy, Co is a co-factor of several enzymes and component of B12 vitamin. However, in concentrations higher or lower than required, P and Co alter algal metabolism, impacting physiological processes (e.

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Anthropogenic activities such as agriculture and industry increase contaminants that reach the water bodies, potentially threatening the biota. Most likely, these pollutants occur in complex mixtures. The effects on organisms can be potentiated (synergism) or reduced (antagonism) according to the interaction between the stressors or the species.

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The magnitude of copepods' responses to pesticides, individually and in mixture, is little understood. The aims of this study were to evaluate: (i) the effects of the pesticides fipronil and 2,4-D, individually and in mixture, on the freshwater copepod Notodiaptomus iheringi; and (ii) the survival and the feeding rate of copepods after the exposure. Acute toxicity tests using the commercial formulations of fipronil and 2,4-D, individually and in mixture, were performed.

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Increasing metal concentrations in aquatic environments are mainly due to anthropogenic actions, which is a matter of concern for the biodiversity of aquatic biota. It is known that metals coexist in environments, however environmental risk assessments do not usually take into account the effects of these mixtures. We aimed to test Zn and Al mixtures on the photosynthetic apparatus of a green microalga, for the first time, using PAM fluorometry.

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When pesticides reach the aquatic environment, they can distribute in water and sediment, increasing the risks to benthic organisms, such as amphipods that play a key role in the aquatic food webs. Thus, the present study assessed the consequences of exposure to the insecticide fipronil and herbicide 2,4-D (alone and in mixture) on biochemical markers, feeding rates and the partial life-cycle of Hyalella meinerti. Three concentrations of fipronil (0.

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Manganese (Mn), an essential metal in trace amounts, and chromium (Cr), a nonessential metal to algae, are often found in effluent discharges and may co-occur in contaminated aquatic environments. Therefore, we investigated the effects of Mn and Cr, and their mixtures, on a freshwater Chlorophyceae, Raphidocelis subcapitata, using a multiple endpoint approach. Regarding the single exposure of metals, Mn was 4 times more toxic (median inhibitory concentration at 72 h [IC50 ] = 4.

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Silver-based materials have microbicidal action, photocatalytic activity and electronic properties. The increase in manufacturing and consumption of these compounds, given their wide functionality and application, is a source of contamination to freshwater ecosystems and causes toxicity to aquatic biota. Therefore, for the first time, we evaluated the toxicity of the silver tungstate (α-AgWO), in different morphologies (cube and rod), for the microalga Raphidocelis subcapitata.

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Conventional farming delivers a range of pesticides to aquatic ecosystems leading to implications for the indigenous species. Due to the multiple applications and persistence of molecules, organisms may be exposed for a prolonged period over multiple generations. The present study outlines a full life-cycle design over three generations of Chironomus sancticaroli exposed to the insecticide fipronil, the herbicide 2,4-D, and their mixtures.

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In the environment, microalgae are exposed to a multitude of stressors simultaneously, inducing physiological adjustments. It is well documented that both phosphorus (P) limitation and trace metals exposure affect microalgal physiology. However, investigations regarding the combination of both P limitation and excess trace metals still deserve attention.

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The aim of this study was to evaluate the effect of phosphorus (P) on the toxicity of zinc (Zn) for the alga Raphidocelis subcapitata. P was provided in three concentrations: 2.3 x 10-4 mol L-1, 2.

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The occurrence of pesticides and their mixtures in the environment can alter the ecological relationships between aquatic food chains. Since fipronil and 2,4-dichlorophenoxyacetic acid (2,4-D) are commonly found together in Brazilian water bodies, the present study aimed to investigate through an integrative approach the toxicity mechanisms of environmentally relevant concentrations of pesticides Regent® 800 WG (active ingredient - a.i.

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Copper oxide nanoparticles (CuO NP) have been produced on a large scale due to their economically interesting thermophysical properties. This heightens the concern about risks they may pose on their release into the environment, possibly affecting non-target organisms. Microalga are important organisms in ecotoxicological studies as they are at the base of the aquatic food chain, but information about their biochemical and photosynthetic changes in response CuO NP are still scarce.

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A large number of metals is present in aquatic ecosystems, often occurring simultaneously, however, the isolated toxicity of them are better well known than their mixtures. Based on that, for the first time we aimed to test the effects of zinc (Zn) and aluminum (Al) mixtures to the microalgae Raphidocelis subcapitata. Regarding isolated toxicity, the 96 h IC of Zn and Al based on specific growth rates occurred, respectively, at 0.

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Annona glabra L. is a semi-deciduous tree that contains several active substances, including secondary metabolites, with antifungal activity. Phytopathogenic strains of the genus Pythium cause billion dollar losses all over the world on natural and crop species.

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Copper is an essential metal for several physiological and metabolic processes, but a narrow range regulate its effect in phytoplankton cells. It can affect the production of biomolecules and be toxic at concentrations slightly above those required, e.g.

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In aquatic environments, copper (Cu) plays important physiological roles in planktonic food chain, such as electron transfer in photosynthesis and constituting proteins that transport oxygen in some arthropods, while at higher concentrations it is toxic on these organisms and higher trophic levels. The combined effects of natural (e.g.

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Microalgae need a variety of nutrients for optimal growth and health. However, this rarely occurs in nature, and if nutrient proportions vary, biochemical changes can occur in phytoplankton community. This may result in modifications of zooplankton food quality, affecting aquatic food chains.

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