Study of routine metabolism and acute toxicity of mycogenic silver nanoparticles on Palaemon pandaliformis (shrimp)

Palaemon pandaliformis is a shrimp species considered as an important indicator of environmental conditions. In this study, the toxicological effects of mycogenic silver nanoparticles obtained using the fungus Aspergillus tubingensis (AgNP-AT) were evaluated on P. pandaliformis. The AgNP-AT were spherical and homogeneous in size. Compared with the untreated group, at 10 μM AgNP-AT, there was a reduction of 60 and 87% for oxygen consumption and ammonia excretion, respectively. In addition to the untreated group, silver nitrate (AgNO3) was also used as a control, where concentrations at least 10 times lower than those of the AgNPs also reduced the oxygen consumption by 54% and increased the ammonia excretion by 33%, demonstrating its high toxicity. At 24, 48, 72 and 96 h, the AgNP-AT showed lethal concentrations (LC50) of 17.4, 14.4, 12.6 and 0.5 μM, while AgNO3 showed LC50 values of 2.5, 1.0, 0.02 and 0.01 μM, respectively. For all groups exposed to AgNPs, histological analysis showed that, in relation to the untreated group, there was a significant increase in the mean area of the shrimps' gills, indicating hypertrophy. All the changes observed in the hepatopancreatic and gill tissue, mainly for AgNPs at the highest concentration of 10 μM, are described as reversible. The results indicated that the AgNP-AT toxicity to the shrimps increased according to the time of exposure. However, it is important to highlight that the AgNP-AT were less toxic than AgNO3 to the shrimps, probably due to the presence of a protein coat in these AgNPs, which is able to control the release of Ag+ ions, avoiding high toxicity to the shrimps.

Effects of mycogenic silver nanoparticles on organisms of different trophic levels.

Biogenic silver nanoparticles (AgNPs) are considered a promising alternative to their synthetic versions. However, the environmental impact of such nanomaterials is still scarcely understood. Thus, the present study aims at assessing the antimicrobial action and ecotoxicity of AgNPs biosynthesized by the fungus Aspergillus niger IBCLP20 towards three freshwater organisms: Chlorella vulgaris, Daphnia similis, and Danio rerio (zebrafish). AgNPs IBCLP20 showed antibacterial action against Klebsiella pneumoniae between 5 and 100 µg mL-1, and antifungal action against Trichophyton mentagrophytes in concentrations ranging from 20 to 100 µg mL-1. The cell density of the microalgae Chlorella vulgaris decreased 40% after 96 h of exposure to AgNPs IBCLP20, at the highest concentration analysed (100 µg L-1). The 48 h median lethal concentration for Daphnia similis was estimated as 4.06 µg L-1 (2.29-6.42 µg L-1). AgNPs IBCLP20 and silver nitrate (AgNO3) caused no acute toxicity on adult zebrafish, although they did induce several physiological changes. Mycosynthetized AgNPs caused a significant increase (p < 0.05) in oxygen consumption at the highest concentration studied (75 µg L-1) and an increase in the excretion of ammonia at the lower concentrations, followed by a reduction at the higher concentrations. Such findings are comparable with AgNO3, which increased the oxygen consumption on low exposure concentrations, followed by a decrease at the high tested concentrations, while impairing the excretion of ammonia in all tested concentrations. The present results show that AgNPs IBCLP20 have biocidal properties. Mycogenic AgNPs induce adverse effects on organisms of different trophic levels and understanding their impact is detrimental to developing countermeasures aimed at preventing any negative environmental effects of such novel materials.

Microbiological quality of the water in collection areas and the tissue of Mytella falcata-Cananéia (SP, Brazil).

Changes in fauna and abiotic factors in estuaries are a consequence of their exploitation; thus, bivalve mollusks, as they filter, are widely used as environmental bioindicators. The aim of this study was to analyze the existence of seasonal variation in the concentration of total coliforms (TC) and thermotolerant coliforms (Ct), in addition to correlating the data obtained with the salinity and temperature in collection areas of Mytella falcata and the soft tissue cultivated in the Estuarine Complex of Cananéia. Two biweekly samples of water and tissue were taken, for 12 consecutive months, in nine cultivation areas of M. falcata. The analysis of the water samples showed that the Fisheries Institute, Mosquiteiro, and Itapitangui have high TC densities, with respective annual averages of 772.22, 592.67, and 563.75 most probable number (MPN).100 ml-1 . The highest concentrations of TC and Ct occurred in the summer, in most areas. There was a decrease in both TC and Ct with increasing salinity. However, there was an increase in Ct with increasing temperature. The soft tissue showed TC densities from 9 to 26 MPN.100 ml-1 and Ct densities from 6 to 14 MPN.100 ml-1 , displaying the highest counts in the summer. Places where coliforms were found in high concentrations could indicate contamination, because Ct do not support higher salinities for a long time. PRACTITIONER POINTS: The general mean was 77.64 (total coliforms) and 39.35 (thermotolerant) MPN.100 ml-1 . Annual average (thermotolerant) exceeded the permitted Brazilian limit in five points. Higher concentrations of total and thermotolerant coliforms occurred in the summer. In mollusk's tissue, concentrations of thermotolerant were 6.30 to 26.16 MPN.100 g-1 . Coliforms' MPN varied with increasing salinity and temperature.

Copper II oxide nanoparticles (CuONPs) alter metabolic markers and swimming activity in zebra-fish (Danio rerio).

The present study aimed to compare the metabolic effects caused by using copper oxide nanoparticles with two distinct morphologies nanorods and nanosphere. The CuONPs in the form of nanorods were characterized in the order of 500 nm, on a scale of 20, 100, and 500 nm. Meanwhile, the nanosphere CuONPs were characterized in the order of 5 nm, on a 30 nm scale. The analysis of metabolic rate was performed using the closed respirometry technique, specific ammonia excretion, and swimming ability as biomarkers, the physiological effects on Danio rerio were investigated. For the experiments, 88 fish were used, exposed for 24 h at concentrations of 0, 50, 100, and 200 µg/L of copper oxide nanoparticles in the form of nanospheres and nanorods, respectively. The tests carried out with the nanorods demonstrated metabolic alterations in fish, with an increase of 294% and 321% in the metabolic rate at concentrations of 100 µg/L and 200 µg/L, respectively. Furthermore, there was a decrease in specific ammonia excretion by 34% and 83% and in swimming capacity by 34% and 55% at concentrations of 100 and 200 µg/L, respectively, when compared to the control. The tests performed with nanospheres did not show significant changes compared to the control. These experiments showed that different morphological structures of the same copper oxide nanoparticle caused different effects on fish metabolism. It is concluded that the characterization of nanoparticles is essential to understand their effects on fish, since their structural forms can cause different toxic effects on D. rerio.

Norovirus GII and astrovirus in shellfish from a mangrove region in Cananéia, Brazil: molecular detection and characterization.

In recent years, annual cases of gastroenteritis have been reported in the world at high rates, suggesting an association with the consumption of shellfish with enteric viruses in their tissues. Anthropic activities are considered a source of environmental pollution and the main responsible for contamination by pathogenic microorganisms in aquatic environments. The objective of this study was to evaluate, by RT-semi-nested PCR, the presence of astrovirus (AstV) and norovirus genogroup II (NoV GII) in mussels (Mytella falcata) and oysters (Crassostrea brasiliana) collected in two sites of the Lagunar Complex of Cananéia, State of São Paulo, Brazil. A total of 150 samples of mussels and oysters (75 samples each) were analyzed. AstV was not identified in any shellfish sample. NoV GII was detected in 21 samples (14%), 8 mussel samples (38%), and 13 oyster samples (62%). From the 21 positive samples, 16 were analyzed by nucleotide sequencing. The molecular characterization revealed that Brazilian samples were grouped into clades along with other sequences from Brazil, Japan, and Mexico. There was 93.8-100% amino acid sequence similarity among the samples in this study and > 94.9% when compared with the strains isolated from clinical cases in Brazil. The screening of shellfish for the presence of health-significant enteric viruses can help prevent outbreaks among consumers and contribute to the improvement of the estuarine environment.

Co-exposure of carbon nanotubes with carbofuran pesticide affects metabolic rate in Palaemon pandaliformis (shrimp).

Palaemon pandalirformis (shrimp) is a species widely distributed in the Brazilian coastal region and with an important economic role. In addition, this organism is considered an indicator of environmental pollution in estuaries; however, its physiological responses to toxic environmental pollutants, including pesticides and nanomaterials, are not well known, mainly, the effects of co-exposure. Thus, the purpose of this study was to evaluate the ecotoxicological effects of co-exposure between oxidized multiwalled carbon nanotubes (HNO3-MWCNT) and carbofuran pesticide on the routine metabolism of P. pandalirformis. The shrimps were exposed to different concentrations of HNO3-MWCNT (0; 10; 100; 500; 1000 µg L-1), carbofuran (0; 0.1; 1.0; 5.0; 10 µg L-1) and to co-exposure with 100 µg L-1 of HNO3-MWCNT + carbofuran (0; 0.1; 1.0; 5.0; 10 µg L-1), to evaluate the effects on metabolic rate (O2 consumption) and excretion of ammonia (NH4+NH3). Our results showed that the shrimps exposed to HNO3-MWCNT (10 µg L-1) increased the metabolic rate by 292% and the excretion of ammonia by 275%; those exposed to carbofuran (10 µg L-1) increased their metabolic rate by 162% and the excretion of ammonia by 425%; and with the co-exposure of HNO3-MWCNT + carbofuran there was also an increase in the metabolic rate by 317% and an excretion of ammonia by 433% when compared to control. These findings provides useful information toward better understanding the physiological responses of shrimps after combined exposure to nanomaterials and pesticides in aquatic environments.

Sublethal effects of propiconazole on the metabolism of lambari Deuterodon iguape (Eigenmann 1907), a native species from Brazil.

The objective of this study was to analyze the sublethal effects of propiconazole on Deuterodon iguape, a native fish common in Brazil, which has potential for aquaculture and use as a bioindicator. The hypothesis was to test whether D. iguape has a metabolism similar to Danio rerio so that its use in bioassays may be validated. Lethal concentration (LC50) and metabolic rates were studied in fish exposed to propiconazole. Specific oxygen consumption and ammonia excretion for D. iguape and D. rerio increased by 0.01 µg L-1 and then decreased as the propiconazole concentration increased. The decrease in the averages of specific oxygen consumption at the concentration of 0.1 µg L-1 represented a reduction in the metabolic rate compared to the control of 71% for D. iguape and 40% D. rerio. For the ammonia excretion, at the same concentration, there was a reduction of 68.7% and 45.4% for D. iguape and D. rerio, respectively. When comparing ammonia excretion of the two species for each concentration of propiconazole, there was a significant difference (p < 0.05) in relation to the control and for the highest concentration (0.1 µg L-1). As for specific oxygen consumption, there was a statistically significant difference only for the concentration of 0.1 µg L-1. D. iguape proved to be a good and useful bioindicator for ichthyologists or ecologists in studies of moderate pesticide contamination in freshwater aquatic environments, as its metabolic response was similar to D. rerio.

Carbofuran affects behavior and metabolism of the Atlantic Forest lambari Deuterodon iguape, a native species from Brazil.

One of the major causes of aquatic biodiversity loss is the contamination of the environment by pesticides. Even though there is a considerable amount of studies on the subject, there are still few that deal with the effects of carbofuran on native species in Brazil. Although carbofuran is widely used in Brazil, its action on native organisms, such as the Atlantic Forest lambari Deuterodon iguape, has not yet been studied. This work aimed to evaluate the effects of exposure to carbofuran on the fish D. iguape, considering the behavior and specific oxygen consumption as end points. Opercular movements, dorsal fin movements, and swimming speed were analyzed as behavioral parameters. To assess specific oxygen consumption, fish were subjected to concentrations of 0.0, 0.05, 0.1, 0.25, and 0.5 mg/L, for 24 h. For behavior analysis, fish remained exposed to carbofuran at concentrations of 0.0, 0.01, 0.05, 0.1, and 0.5 mg/L, in periods of 0, 2, 24, and 48 h. The behavior was studied through filming, analyzed with the free software, Tracker 4.92 (Open Source Physics). The results demonstrate an increase in opercular movements (18% ± 2.65) and a decrease in dorsal fin movements (- 21.2% ± 2.97), as well as in swimming speed (- 58.3% ± 1.83) of the experimental groups compared to the control group. There was an increase in oxygen consumption of 58.4% in fish exposed to the highest concentration of carbofuran. Thus, it is concluded that carbofuran altered D. iguape's behavior and oxygen consumption. The species was sensitive to carbofuran concentrations and can be used as a bioindicator.

Effect of Fluoxetine Hydrochloride on Routine Metabolism of Lambari (Deuterodon iguape, Eigenmann, 1907) and Phantom Shrimp (Palaemon pandaliformis, Stimpson, 1871)

HIGHLIGHTS Fluoxetine increases the metabolic rate and excretion of ammonia in both species. O:N ratio in fish showed higher values in the highest concentrations of fluoxetine. The LC50 - 96 hour values of Palaemon pandaliformis represented greater toxicity. Both species are a good biological model for fluoxetine exposure studies.

Abstract Fluoxetine is an emerging pollutant that acts as a selective serotonin reuptake inhibitor (SSRI) and being a hydrolytic molecule that is photolytically stable and accumulaties in biological tissues, its disposal in the aquatic environment can interfere with the physiology of fish and shrimp. Thus, the objective of this study was to analyze the effects of fluoxetine on routine metabolism (metabolic rate, specific ammonia excretion and O:N ratio) of Deuterodon iguape and Palaemon pandaliformis. For this, five groups of each species, were exposed to different concentrations of fluoxetine for 24 hours (D. iguape) and 2 hours (P. pandaliformis). The results demonstrated that in D. iguape exposure to fluoxetine significantly increased both the metabolic rate by 75%, 85%, 55% and 50% for concentrations of 0.05; 0.1; 0.5 and 1.0 mgL-1, respectively, and the specific ammonia excretion by 40%, 48% and 20% for concentrations of 0.05; 0.1 and 0.5 mgL-1, respectively, when compared with their control. The O:N ratio was statistically greater in concentrations of 0.5 and 1.0 mgL-1. Concerning P. pandaliformis, exposure to fluoxetine increased metabolic rate at concentrations 30.0 and 60.0 µgL-1, and also increased specific ammonia excretion at concentrations 10.0, 30.0 and 60.0 µgL-1, when compared with the control group. It was concluded that exposure to fluoxetine increases the routine metabolism of both species and that at the concentration 1.0 mgL-1, Deuterodon iguape required different energy substrates.

Evaluation of trace elements in feathers of young kelp gull Larus dominicanus along the coast of Santa Catarina, Brazil.

Seabirds are used as bioindicators of marine ecosystems, especially for quantifying and tracking pollution sources. The objective of this study was to evaluate the contamination in feathers of young kelp gulls by lead (Pb), chromium (Cr), mercury (Hg) and zinc (Zn) on three islands of southern Brazil. The highest values for Pb (2.1310 µg g-1) and Hg (0.0010 µg g-1) were observed in Lobos. Zn was common in all samples with a median around 41.7487 µg g-1 and Cr values were below the quantification limit (0.0300 µg g-1). The Kruskal-Wallis test indicated significant differences in Pb (H = 21.84; p < 0.05) and Zn (H = 958.80; p < 0.05), but no differences were observed in Cr (H = 3.08; p < 0.05) and Hg (H = 3.0; p < 0.05). This study was important to show the impact of trace element pollutants on the seabird communities and oceans.

Metabolic effects in the freshwater fish Geophagus iporangensis in response to single and combined exposure to graphene oxide and trace elements.

Graphene oxide (GO) is part of a new set of nanomaterials with particular characteristics related to its nanoscale size. Due to this feature, it presents high reactivity and other contaminants present in the environment could bind to them and affect its intrinsic toxicity. The metabolic effects of such nanomaterials and their combination with two common pollutants, zinc and cadmium, on the freshwater fish Geophagus iporangensis are analyzed. Moreover, metabolic rate and ammonia excretion were used as bioindicators to measure metabolic changes. Fishes were exposed for 24 h in filtered tap water to different concentrations of GO (0.5; 1.0; 2.0 and 4.0 mg L-1), Zn (0.5; 1.0; 2.0; 4.0 and 10.0 mg L-1) and Cd (0.1; 0.5; 1.0; 2.0 and 4.0 mg L-1). Combined effects were verified using the same concentrations of trace elements added to 1.0 mg L-1 of GO. Exposure to GO and Cd resulted in a decrease of metabolic rate in G. iporangensis, by about 30% compared to control means, in the highest concentration tested (4.0 mg L-1). However, zinc exposure in the highest concentration (10 mg L-1) raised metabolic rate to around three times that of the control group. Ammonia excretion was not affected by exposure to GO and Cd. In contrast, exposure to Zn at 10 mg L-1 raised the rate to around 47%. The combined exposure of GO and Zn intensified the effects of the trace element, inducing responses in both biomarkers at lower concentrations and demonstrating that the interaction between elements increases zinc's effects. The combination Cd + GO only affects metabolic rate. Thus, this metabolic rate alone reveals that combined exposure potentiates effects of trace elements on fish metabolism.

Determinação de bactérias do grupo dos coliformes no tecido mole de Mytella guyanensis extraídas em Cananéia/SP, Brasil / Detecting bacteria of the coliform group in the soft tissue of Mytella guyanensis extracted in Cananéia/SP, Brazil

Esta pesquisa teve por objetivo avaliar a qualidade microbiológica de amostras da água e do tecido de Mytella guyanensis (Mollusca: Bivalva) espécie de relevante interesse comercial e que faz parte direta da renda e alimentação das comunidades tradicionais em regiões litorâneas. Este estudo foi realizado em duas comunidades do Estuário de Cananeia conhecidos como Retiro e Itanhoapina. Durante o período de 2017, onde a espécie é coletada para consumo humano, as amostras de água e do bivalve foram coletadas nas localidades a fim de determinar as concentrações de coliformes totais e termotolerantes. As Amostras de água e de M. guyanensis foram analisadas para determinar o Número Mais Provável de Coliformes (NMP), baseado na Técnica de Tubo Múltiplo. Os resultados das analises, demonstraram baixas concentrações de coliformes nas amostras de água, tendo ocorrido resultado semelhante para as amostras de tecidos dos indivíduos coletados. A análise da água apresentou média geométrica de 34,81 coliformes totais e 20,70 MPN 100 mL-1 de coliformes termotolerantes. As médias de coliformes nos tecidos moles de M. guyanensis foram de 190 MPN g-1 para coliformes totais e 174 MPN g-1 para coliformes termotolerantes. As concentrações de coliformes no tecido dos espécimes coletados, apresentaram correlação positiva com a temperatura e negativa com a salinidade. Houve diferenças significativas entre a sazonalidade em relação à concentração de coliformes totais e termotolerantes no tecido. O verão período de chuvas, apresentou a maior média sazonal de coliformes em M. guyanensis. Todas os valores obtidos para NMP de coliformes estiveram abaixo do limite estabelecido pela legislação.

This study aimed to evaluate the microbiological quality of water and tissue samples of Mytella guyanensis (Mollusk: Bivalve), a species of relevant commercial interest and is a direct part of the income and food of traditional communities in coastal regions. This study was carried out in two communities in the Cananeia Estuary known as Retiro and Itanhoapina. During the period of 2017, where the species is collected for human consumption, water and bivalve samples were collected in the localities in order to determine the concentrations of total and thermotolerant coliforms. The samples of water and M. guyanensis were analyzed to determine the Most Probable Number (MPN) of Coliforms, based on the Multiple Tube Technique. The results of the analyses showed low concentrations of coliforms in the water samples, with a similar result for the tissue samples of the individuals collected. The water analysis showed a geometric mean of 34.81 total coliforms and 20.70 MPN 100 mL-1 of thermotolerant coliforms. The averages of coliforms in the soft tissues of M. guyanensis were 190 MPN g -1 for total coliforms and 174 MPN g -1 for thermotolerant coliforms. The concentrations of coliforms in the tissue of the collected specimens showed a positive correlation with temperature and a negative correlation with salinity. There were significant differences between seasonality in relation to the concentration of total and thermotolerant coliforms in the tissue. The summer rainy season showed the highest seasonal average of coliforms in M. guyanensis. All values obtained for MPN of coliforms were below the limit established by the legislation.

Co-exposure of graphene oxide with trace elements: Effects on acute ecotoxicity and routine metabolism in Palaemon pandaliformis (shrimp).

Graphene oxide (GO) has been evaluated for application in environmental remediation and pollution control strategies. However, the side effects caused by the interactions of GO with classical pollutants in aquatic environments are still largely unknown. In this work, the ecotoxicological effects of GO, cadmium, zinc and the interactions between GO and these trace elements (co-exposure) were evaluated through acute toxicity tests and routine metabolism (i.e., oxygen consumption and ammonia excretion) in Palaemon pandaliformis (shrimp). After 96 h of exposure, GO did not present acute ecotoxicity at concentrations up to 5.0 mg L-1. However, the association of GO with Cd or Zn increased the toxicity of these trace elements as demonstrated by the decrease in LC50 values. The 96 h LC50 of Cd associated with GO was 1.7 times less than the 96 h LC50 of Cd alone. Similarly, the 96 h LC50 of Zn associated with GO was 1.8 times less than the 96 h LC50 of Zn alone. Additionally, the co-exposure of GO with trace elements impaired the routine metabolism of P. pandaliformis. Finally, the GO potentiated the ecotoxicological effects of Cd and Zn in the shrimp model. Future research on this emerging nanomaterial should focus on its use and disposal in aquatic ecosystems.

Effects of multiwalled carbon nanotubes and carbofuran on metabolism in Astyanax ribeirae, a native species.

The study of the toxic effect of carbofuran and multiwalled carbon nanotubes (MWCNTs) on Astyanax ribeirae metabolism is of paramount importance due to the increasing use of this pesticide in agriculture and in the production of nanotubes within the material industry. This study aimed to evaluate the effects of carbofuran, MWCNT, and the combination of these compounds on specific oxygen consumption and excretion of ammonia in A. ribeirae. Therefore, 65 fish were divided into three groups of treatments at varying concentrations: carbofuran (0.01, 0.05, 0.1, and 0.5 mg/L), MWCNT (0.1, 0.25, 0.5, and 1.0 mg/L), and 0.5 mg/L of MWCNT added to carbofuran concentrations (0.01, 0.05, 0.1, and 0.5 mg/L). The average specific oxygen consumption in the groups exposed to carbofuran, compared to the control, increased 73.49% at the 0.01 mg/L concentration and decreased 63.86% and 91.57% with treatments of 0.1 and 0.5 mg/L, respectively. For groups exposed to the MWCNT, there was an 83.91% drop with the 1.0 mg/L treatment, and the carbofuran + MWCNT groups recorded a decrease of 71.09%, 92.77%, and 93.98% at concentrations of 0.05, 0.1, and 0.5 mg/L, respectively. In relation to specific ammonia excretion, in groups exposed to carbofuran compared to the control, there was an increase of 134.37% and 200% with the 0.1 and 0.5 mg/L treatments, respectively. The group exposed to carbofuran + MWCNT experienced a decrease of 60% and 80% with treatments of 0.1 mg/L carbofuran + 0.5 mg/L MWCNT and 0.5 mg/L carbofuran + 0.5 mg/L MWCNT, respectively. Therefore, it was concluded that carbofuran + MWCNT interact, increasing the effects in Astyanax sp.

Coating carbon nanotubes with humic acid using an eco-friendly mechanochemical method: Application for Cu(II) ions removal from water and aquatic ecotoxicity.

In this work, industrial grade multi-walled carbon nanotubes (MWCNT) were coated with humic acid (HA) for the first time by means of a milling process, which can be considered an eco-friendly mechanochemical method to prepare materials and composites. The HA-MWCNT hybrid material was characterized by atomic force microscopy (AFM), scanning electron microscopies (SEM and STEM), X-ray photoelectron spectroscopy (XPS), termogravimetric analysis (TGA), and Raman spectroscopy. STEM and AFM images demonstrated that the MWCNTs were efficiently coated by the humic acid, thus leading to an increase of 20% in the oxygen content at the nanotube surface as observed by the XPS data. After the milling process, the carbon nanotubes were shortened as unveiled by SEM images and the values of ID/IG intensity ratio increased due to shortening of the nanotubes and increasing in the number defects at the graphitic structure of carbon nanotubes walls. The analysis of TGA data showed that the quantity of the organic matter of HA on the nanotube surface was 25%. The HA coating was responsible to favor the dispersion of MWCNTs in ultrapure water (i.e. -42mV, zeta-potential value) and to improve their capacity for copper removal. HA-MWCNTs hybrid material adsorbed 2.5 times more Cu(II) ions than oxidized MWCNTs with HNO3, thus evidencing that it is a very efficient adsorbent material for removing copper ions from reconstituted water. The HA-MWCNTs hybrid material did not show acute ecotoxicity to the tested aquatic model organisms (Hydra attenuata, Daphnia magna, and Danio rerio embryos) up to the highest concentration evaluated (10mgL-1). The results allowed concluding that the mechanochemical method is effective to coat carbon nanotubes with humic acid, thus generating a functional hybrid material with low aquatic toxicity and great potential to be applied in environmental nanotechnologies such as the removal of heavy metal ions from water.

Microbiology as an indicator of environmental health of Ilha Comprida lagoons- SP / Microbiologia como indicador da saúde ambiental das lagoas de Ilha Comprida - SP

With an area of 150 Km², the municipality of Ilha Comprida has limited sources of freshwater, sediments and nutrients. However, the sanitary aspects, aiming at Public Health, should be evaluated by determining the densities and the distribution of fecal pollution indicators, mainly bacteria from the group of thermotolerant coliforms. Thus, the objective of this work was to analyze the seasonal variations in the densities of thermotolerant coliforms in the lagoons of the municipality of Ilha Comprida (SP). For that, water samples were collected, in the period between 2014 and 2016, in lagoons of 13 localities (Juruvaúva, City Mar Sul, City Mar Norte, São Januário, Jardim Portugal, Atlântico, Icaraí, Adriana Sul, Adriana Norte, Porto Velho 2, Xandú, Jardim da Barra, Laguna Ponta da Praia) located in the municipality of Ilha Comprida (SP). The results showed that 21.90% of the samples were above the limit established by CONAMA. High densities of bacteria were found in the Icaraí lagoon. The highest averages of thermotolerant coliform densities were recorded in summer and spring. It is concluded that the seasonal variation interferes with the density of thermotolerant coliforms

Com uma área de 150 km², o município de Ilha Comprida tem fontes limitadas de água doce, sedimentos e nutrientes. No entanto, os aspectos sanitários, que visam a Saúde Pública, devem ser avaliados determinando as densidades e a distribuição de indicadores de poluição fecal, principalmente bactérias do grupo de coliformes termotolerantes. Assim, o objetivo deste trabalho foi analisar as variações sazonais nas densidades de coliformes termotolerantes nas lagoas do município de Ilha Comprida (SP). Para isso, foram coletadas amostras de água, no período entre 2014 e 2016, em lagoas de 13 localidades (Juruvaúva, Cidade do Mar do Sul, Cidade do Mar do Norte, São Januário, Jardim Portugal, Atlântico, Icaraí, Adriana Sul, Adriana Norte, Porto Velho 2, Xandú, Jardim da Barra, Laguna Ponta da Praia), localizada no município de Ilha Comprida (SP). Os resultados mostraram que 21,90% das amostras estavam acima do limite estabelecido pelo CONAMA. Foram encontradas altas densidades de bactérias na lagoa de Icaraí. As médias mais elevadas das densidades de coliformes termotolerantes foram registradas no verão e na primavera. Conclui-se que a variação sazonal interfere com a densidade de coliformes termotolerantes

Comparison of bacterial densities and resistance in different beach compartments: should water be our main concern? / Comparação de densidade e resistência bacterianas em diferentes compartimentos de praia: a água deve ser nossa principal preocupação?

Coastal regions are very important, since they provide food, enable economic and leisure activities however, the increase in urbanization of coastal areas are accompanied by great volumes of organic effluent, which is sometimes discharged in natura in water bodies, increasing the risk of the presence of pathogenic resistant bacteria in marine environments. In fact, recent studies showed higher bacterial densities in sediments than in water, since its present more favorable conditions for bacterial survivor (e.g. sun protection and predation). In addition, bivalves tend to accumulate suspended bacteria from the water, since they are filter feeding organisms. Thus, the present study evaluated densities and resistance to antibiotics of Enterococcus sp., Escherichia coli and Aeromonas sp. in water, sediment and mussels samples. Samples were collected at Praia dos Sonhos (Itanhaém) and Ubuqueçaba Island (Santos). Bacterial densities were determined by Membrane Filter Technique and the isolated strains were submitted to antibiotic sensibility test. Bacterial densities were lower in water and higher in sediments and mussels samples. Bacterial strains from Santos presented higher frequencies of resistance than those isolated from Itanhaém (less impacted area). Aeromonas strains were more resistant to Cefalotin and Cefuroxin, Enterococcus to Gentamicin and Streptomicin, and E. coli to Vancomicin and Eritromicin. The results obtained point to the need to establish public policies, laws and monitoring programs about the microbiological quality of mollusks and sediments, including the use of Enterococcus sp as microbiological indicator as well as about the resistance of the bacteria present in these environments

As regiões costeiras são muito importantes, uma vez que proporcionam alimentos, permitem atividades econômicas e de lazer, no entanto, o aumento da urbanização das áreas costeiras é acompanhado por grandes volumes de efluentes orgânicos, que às vezes são descarregados in natura em corpos d'água, aumentando o risco da presença de bactérias patogênicas e resistentes em ambientes marinhos. De fato, estudos recentes mostraram maiores densidades bacterianas nos sedimentos do que na água, pois apresentam condições mais favoráveis para a sobrevivência bacteriana (e.g. proteção solar e de predação). Além disso, os bivalves tendem a acumular bactérias suspensas da água, pois são organismos que alimentam-se por filtração. Assim, o presente estudo avaliou densidades e resistência a antibióticos de Enterococcus sp., Escherichia coli e Aeromonas sp. em amostras de água, sedimentos e mexilhões. As amostras foram coletadas na Praia dos Sonhos (Itanhaém) e na Ilha Ubuqueçaba (Santos). As densidades bacterianas foram determinadas pela técnica de filtro de membrana e as cepas isoladas foram submetidas ao teste de sensibilidade aos antibióticos. As densidades bacterianas foram menores na água e maiores nas amostras de sedimentos e mexilhões. As cepas bacterianas de Santos apresentaram maiores frequências de resistência do que as isoladas de Itanhaém (área menos impactada). As cepas de Aeromonas foram mais reistentes à Cefalotina e Cefuroxime, Enterococcus à Gentamicina e Estreptomicina, e E. coli à Vancomicina e Eritromicina. Os resultados obtidos apontam para a necessidade de estabelecer políticas públicas, leis e programas de monitoramento relativos à qualidade microbiológica de moluscos e sedimentos, incluindo o uso de Enterococcus sp. como indicador microbiológico, bem como sobre a resistência das bactérias presentes nesses ambientes

Histopathological Effects on Gills of Nile Tilapia (Oreochromis niloticus, Linnaeus, 1758) Exposed to Pb and Carbon Nanotubes.

The effect of heavy metal in fish has been the focus of extensive research for many years. However, the combined effect of heavy metals and nanomaterials is still a new subject that needs to be studied. The aim of this study was to examine histopathologic alterations in the gills of Nile tilapia (Oreochromis niloticus) to determine possible effects of lead (Pb), carbon nanotubes, and Pb+carbon nanotubes on their histological integrity, and if this biological system can be used as a tool for evaluating water quality in monitoring programs. For this, tilapia were exposed to Pb, carbon nanotubes and Pb+carbon nanotubes for 4 days. The main alterations observed were epithelial structure, hyperplasia and displacement of epithelial cells, and alterations of the structure and occurrence of aneurysms in the secondary lamella. The most severe alterations were related to the Pb+carbon nanotubes. We conclude that the oxidized multi-walled carbon nanotubes enhanced the acute lead toxicity in Nile tilapias. This work draws attention to the implications of carbon nanomaterials released in the aquatic environment and their interaction with classical pollutants.

Histopathological alterations in the gills of Nile tilapia exposed to carbofuran and multiwalled carbon nanotubes.

Carbofuran is a nematicide insecticide with a broad spectrum of action. Carbofuran has noxious effects in several species and has been banned in the USA and Europe; however, it is still used in Brazil. Aquatic organisms are not only exposed to pesticides but also to manufactured nanoparticles, and the potential interaction of these compounds therefore requires investigation. The aim of this study was to examine the histopathological alterations in the gills of Nile tilapia (Oreochromis niloticus) to determine possible effects of exposure to carbofuran, nitric acid-treated multiwalled carbon nanotubes (HNO3-MWCNTs) and the combination of carbofuran with nanotubes. Juvenile fish were exposed to different concentrations of carbofuran (0.1, 0.5, 2.0, 4.0 and 8.0mg/L), different concentrations of HNO3-MWCNTs (0.5, 1.0 and 2.0mg/L) or different concentrations of carbofuran (0.1, 0.5, 2.0, 4.0 and 8.0mg/L) with 1.0mg/L of HNO3-MWCNTs. After 24h of exposure, the animals were removed from the aquarium, the spinal cord was transversely sectioned, and the second gill arch was removed for histological evaluation. Common histological changes included dislocation of the epithelial cells, hyperplasia of the epithelial cells along the secondary lamellae, aneurism, and dilation and disarrangement of the capillaries. All the groups exposed to carbofuran demonstrated a dose-dependent correlation in the Histological Alteration Index; the values found for carbofuran and carbon nanotubes were up to 25% greater than for carbofuran alone. This result indicates an interaction between these toxicants, with enhanced ecotoxic effects. This work contributes to the understanding of the environmental impacts of nanomaterials on aquatic organisms, which is necessary for the sustainable development of nanotechnologies.

Ecotoxicological analysis during the removal of carbofuran in fungal bioaugmented matrices.

Biomixtures are used for the removal of pesticides from agricultural wastewater. As biomixtures employ high content of lignocellulosic substrates, their bioaugmentation with ligninolytic fungi represents a novel approach for their enhancement. Nonetheless, the decrease in the concentration of the pesticide may result in sublethal concentrations that still affect ecosystems. Two matrices, a microcosm of rice husk (lignocellulosic substrate) bioaugmented with the fungus Trametes versicolor and a biomixture that contained fungally colonized rice husk were used in the degradation of the insecticide/nematicide carbofuran (CFN). Elutriates simulating lixiviates from these matrices were used to assay the ecotoxicological effects at sublethal level over Daphnia magna (Straus) and the fish Oreochromis aureus (Steindachner) and Oncorhynchus mykiss (Walbaum). Elutriates obtained after 30 d of treatment in the rice husk microcosms at dilutions over 2.5% increased the offspring of D. magna as a trade-off stress response, and produced mortality of neonates at dilutions over 5%. Elutriates (dilution 1:200) obtained during a 30 d period did not produce alterations on the oxygen consumption and ammonium excretion of O. mykiss, however these physiological parameters were affected in O. aureus at every time point of treatment, irrespective of the decrease in CFN concentration. When the fungally colonized rice husk was used to prepare a biomixture, where more accelerated degradation is expected, similar alterations on the responses by O. aureus were achieved. Results suggest that despite the good removal of the pesticide, it is necessary to optimize biomixtures to minimize their residual toxicity and potential chronic effects on aquatic life.