Cyanotoxins and water quality parameters as risk assessment indicators for aquatic life in reservoirs.

We assessed the extent of pollution in an essential public water supply reservoir (southeastern Brazil). An environmental monitoring study was performed at the Billings Reservoir (at the water catchment site) to assess the water quality in 2017, 2018, and 2019. Physicochemical parameters were analyzed, quantifying the total cyanobacteria and the cyanotoxins microcystins (MCs) and saxitoxins (SXTs), as well as their possible ecological risk to the aquatic environment.

Gene expression changes in Epinephelus marginatus (Teleostei, Serranidae) liver reveals candidate molecular biomarker of iron ore contamination.

Wastes from iron ore mining activities are potentially damaging to adjacent aquatic ecosystems. We aimed to determine biomarkers of environmental exposure to this xenobiotic in the dusky grouper Epinephelus marginatus by differential gene expression analysis. For this, fish were exposed to iron ore (15.

Response of Oreochromis niloticus (Teleostei: Cichlidae) exposed to a guanitoxin-producing cyanobacterial strain using multiple biomarkers.

Changes in environmental conditions in aquatic ecosystems caused by anthropic actions can modify the composition of primary producers, promoting the excessive proliferation of cyanobacteria. These organisms can form cyanobacterial blooms, which directly affect aquatic life. The present study investigated the mutagenicity of the cyanobacterium Sphaerospermopsis torques-reginae (strain ITEP-024), guanitoxin-producing (natural organophosphate), and sublethal effects on fish in relevant environment concentrations.

Seasonality effects on the metal concentration and biochemical changes in Astyanax lacustris (Teleostei: Characiformes) from Doce River after the collapse of the Fundão dam in Mariana, Brazil.

This study aimed to evaluate the harmful effects of metal accumulation on Astyanax lacustris and their biochemical response when exposed to the metals contained in the Doce River water, Brazil. The study was carried out in the Baixo Guandu region of the Doce River, Espírito Santo state. Samples were collected during the dry and wet seasons.

Gene Expression Changes in Epinephelus marginatus (Teleostei, Serranidae) Liver as Molecular Biomarker of Iron Ore Contamination.

The aim of this study was to determine selected molecular biomarkers of iron ore contamination in Epinephelus marginatus. Molecular biomarkers were tested by checking the relative expression of genes involved in oxidative stress, trace element regulation, and cellular damage, by RT-qPCR. Iron ore exposure caused the downregulation of ferroportin (FP) gene expression and a significant upregulation in superoxide dismutase (SOD) and cytochrome P450 1A (CYP1A) genes.

Microplastic and artificial cellulose microfibers ingestion by reef fishes in the Guarapari Islands, southwestern Atlantic.

This study investigated the ingestion of microplastics and artificial cellulose particles by 103 specimens belonging to 21 reef fish species from the southwestern Atlantic. Specimens of six species had ingested microplastics and artificial cellulose particles, while those of another three species had ingested only one type of material. In our samples, man-made cellulose fibers were more common than microplastics.

De novo assembly and annotation of the transcriptome of Astyanax lacustris liver unveil candidate genes to monitor response to environmental stress.

Astyanax lacustris is a freshwater characid fish species that inhabits small streams, lakes and rivers in South America. These fish are abundant in the wild and highly adaptable in captive, being considered a good model for ecotoxicological studies. Nevertheless, there are only shortcoming gene sequence information available in public databases, which hinder their use in more comprehensive investigations that employ sensitivity molecular biology techniques to assess gene expression profile for biomarker identification.

The effectiveness of surfactants applied with essential oil of Lippia alba in the anesthesia of Nile tilapia (Oreochromis niloticus) and their toxicity assessment for fish and mammals.

The Lippia alba essential oil (EO) is a fish anesthetic immiscible in water and commonly used diluted in ethanol. We evaluated the effectiveness of surfactant use with Lippia alba EO in the anesthesia of Oreochromis niloticus, as well as its toxicity in fish and mammals. The EO was extracted by hydrodistillation and the fish were exposed to anesthesia at the concentration of 250 μL/L for 10 min with the surfactants polysorbate 20 (T20), polysorbate 80 (T80), polyethylene glycol (PEG), and ethanol.

Toxicity of Copper in Epinephelus marginatus (Perciformes; Serranidae) After Ingestion of Contaminated Food.

The dusky grouper Epinephelus marginatus is predator fish subjected to be impacted due to the contamination of their habitats. A viable source of metal contamination, i.e.

Is the Doce River elutriate or its water toxic to Astyanax lacustris (Teleostei: Characidae) three years after the Samarco mining dam collapse?

In 2015, after the Fundão dam failure, in Minas Gerais State, Brazil, around 50 million cubic meters of sludge from iron mining tailings were discharged into the Doce River. After the dam collapse, surpassing concentrations of metals were observed in the river sediment, which could be harmful to aquatic organisms, including the fishes. The present study aimed to evaluate the toxic effects of both elutriate and water, collected from the Doce River, on Astyanax lacustris three years after the dam failure.

Metals, arsenic, pesticides, and microcystins in tilapia (Oreochromis niloticus) from aquaculture parks in Brazil.

The production of Nile tilapia (Oreochromis niloticus) in Brazil exhibits the highest growth rate in the world and represents approximately 45% of the total fish production. The objective of the present study was to assess the risk for human health due the consumption of tilapia farmed in net cages in eight aquaculture parks in Brazil. The concentrations of pesticides (40 compounds), metals (Mn, Ni, Zn, Cd, Pb, and Sn), arsenic, and cyanotoxins (microcystins) were evaluated in 16 fish from each park.

Geophagus brasiliensis (Teleostei: Cichlidae) as an indicator of toxicity of ornamental stone processing wastes.

Massive exploitation of geological resources may lead to environmental issues due to the inadequate disposal of the processing wastes, which are potentially hazard to terrestrial and aquatic environments. To evaluate the toxic effects ornamental stones processing wastes (OSPW), Geophagus brasiliensis fish were contaminated with different concentrations of OSPW (250, 500, 750 and 1000 mg/L). The contaminated aquarium water showed increased total hardness and Ca, Na, K, Mg and Mn content, which lead to bioconcentration of Na, K and Mg in G.

Toxic effects of ornamental stone processing waste effluents on Geophagus brasiliensis (Teleostei: Cichlidae).

The ornamental stone industry generates considerable amounts of waste (OSPW), which may eventually reach natural environments and impact the local ecosystem. The aim of this study was to compare the toxic effects of two OSPW effluents in Geophagus brasiliensis: i) leachate effluent from a lagoon in an OSPW landfill (LE) and ii) decanted effluent from an ornamental stone processing industry (DE). G.

Temperature affects the toxicity of lead-contaminated food in Geophagus brasiliensis (QUOY & GAIMARD, 1824).

Lead is toxic to fish, and its toxicity can be aggravated by the water temperature. Geophagus brasiliensis populations are geographically widespread and thus live in areas with different temperatures. The objective of this work was to evaluate the effects of lead-contaminated feed in fish (Geophagus brasiliensis) exposed to different temperatures.

High waterborne Mg does not attenuate the toxic effects of Fe, Mn, and Ba on Na regulation of Amazonian armored catfish tamoatá (Hoplosternum litoralle).

Formation water (FoW) is a by-product from oil and gas production and usually has high concentrations of soluble salts and metals. Calcium (Ca) and magnesium (Mg) have been shown to reduce the toxicity of metals to aquatic animals, and previous study showed that high waterborne Ca exerts mild effect against disturbances on Na regulation in Amazonian armored catfish tamoatá (Hoplosternum littorale) acutely exposed to high Fe, Mn, and Ba levels. Here, we hypothesized that high Mg levels might also reduce the toxic effects of these metals on Na regulation of tamoatá.

Genotoxic effect of Lippia alba (Mill.) N. E. Brown essential oil on fish (Oreochromis niloticus) and mammal (Mus musculus).

"Erva cidreira" (Lippia alba (Mill.) N. E.

The effects of subchronic exposure to copper in fat snook (Centropomus parallelus).

Anthropogenic processes affect different communities through the release of contaminated effluents into water bodies. Copper can be found in the effluents of most industrial processes and in other effluent types. The fat snook Centropomus parallelus, found from Florida in the United States to southern Brazil, is of great economic importance and is used as a food resource near the coast.

Effect of dietary cadmium on fitness, growth, genotoxicity and accumulation in the Yellow-spotted River Turtle, Podocnemis unifilis.

The aim of this study was to expose the Yellow-spotted River Turtle, Podocnemis unifilis, to dietary cadmium (Cd) contamination. The P. unifilis were fed with a Cd contaminated diet (590 µgg(-1)) or a control diet for 30 and 60 days.

Recovery of fat snook, Centropomus parallelus (Teleostei: Perciformes) after subchronic exposure to copper.

We studied the recovery of juvenile fat snook (Centropomus parallelus) after subchronic exposure to different concentrations of copper. Healthy juveniles (1.98 g) were exposed to 25 or 50 μg Cu/L for 30 days (12 replicates with 5 fish in each one), and recovery was observed at 0, 4, 10, and 30 days after exposure (3 replicates with 5 fish in each one).

Sodium fluxes in tamoatá, Hoplosternum litoralle, exposed to formation water from Urucu Reserve (Amazon, Brazil).

Formation water (produce water or oil field brine) from oil and gas production usually has high concentrations of soluble salts and metals. The objective of this study was to examine the effect of formation water from Urucu Reserve, Amazon, on whole-body uptake and internal distribution of newly accumulated Na+ in juvenile tamoatá, Hoplosternum litoralle. Groups of fish were submitted to nine treatments for 3 h in 400-ml chambers: control (well water), 5% formation water, and well water with respective concentrations of 5% formation water of Ca2+, Fe, Mn, Ba2+, Fe+Ca2+, Mn+Ca2+, and Ba+Ca2+ added.

Social relationship as inducer of immunological and stress responses in matrinxã (Brycon amazonicus).

Matrinxã (Brycon amazonicus) is a freshwater neotropical fish species with a social interaction and aggressive behavior, especially in crowded environments. This species' social structure is established by agonistic interactions, which increase significantly at the fifth hour, when compared to the first and second hours of confinement, when each dominant fish competes with other individual for a conditioned territorialism. This social relationship also induces a complex physiological response in the organism, which generates an acute stimulation from the stressor agent.

Net ion fluxes in the facultative air-breather Hoplosternum littorale (tamoata) and the obligate air-breather Arapaima gigas (pirarucu) exposed to different Amazonian waters.

Fishes that live in the Amazon environment may be exposed to several kinds of water: black water (BW), acidic black water (pH 3.5) (ABW) and white water (WW), among others. The aim of the present study was to analyze net ion fluxes in the facultative air-breather Hoplosternum littorale (tamoata) and the obligate air-breather Arapaima gigas (pirarucu) exposed to different types of water.