Phytoremediation, bioaccessibility and ecotoxicological risk assessment of arsenic in a gold mining area.

The physicochemical and biological parameters of aquatic ecosystems are directly affected by mining activities, increasing the ecotoxicological risk related to exposure to contaminants and pollutants. In this study, a native and adapted floating aquatic macrophyte was used in a gold mining area as a model organism to assess the environmental risk and its potential application in bioremediation of heavy metals. The physicochemical parameters of water and sediments were evaluated, as well as the phytoremediation parameters (bioconcentration and translocation factors) of Hydrocotyle ranunculoides L. The results showed a significant bioconcentration of Cr, Pb, Cu, and Zn in the roots of the macrophyte (high BCF: As > Cu > Zn > Pb > Cr), confirming its suitability for use in rhizofiltration. Regarding arsenic bioconcentration, H. ranunculoides demonstrated a high BCF and TF > 1, indicating its phytoextraction potential, an essential requirement for plants to be used in bioremediation programs.

Using native fish in eco-genotoxic assessment of heavy metal contamination pollution arising from nearby large Brazilian rivers.

Worldwide water quality has declined progressively due to continuous pollution of aquatic resources by agrochemicals in particular heavy metals. Fish genotoxicity biomarkers are vital to identify and complement chemical parameters for determining environmental risk of adverse effects. Therefore, it was of interest to examine the eco-genotoxicity attributed to water pollution over different stream sections of Brazilian rivers by using Cichlasoma paranaense (Teleostei: Cichlidae), a neotropical freshwater cichlid fish, as a biological model. Chemical analysis of water and sediments collected from different Brazilian rivers sites demonstrated contamination by metals. Cichlasoma paranaense were collected at a reference location (a permanent water preservation area), maintained in the lab under standard conditions (controlled temperature, lighting, daily feeding, and constant aeration) and exposed to environmental samples of water and sediments. Subsequently, micronucleus (MN) and nuclear abnormalities (NA) frequencies were assessed in erythrocytes obtained from the caudal and gill regions. The highest concentrations of Cu were found in samples from river sites with forest fragmentation attributed to intensive agriculture practices. Similarly, exposure of fish to samples from agricultural areas induced significantly higher number of genotoxic effects. There was no marked difference between the tissues (tail and gill) regarding the observed frequencies of MN and NA. Thus C. paranaense fish served as a reliable model for detecting genotoxic effects, especially when water samples were collected near the discharge of agrochemicals. Evidence indicates that this method be considered for other global river sites which are also exposed to agrochemicals discharges containing Cu.

Ecotoxicological assessment of water and sediment river samples to evaluate the environmental risks of anthropogenic contamination.

Several studies have shown the issue of effluent discharges as a source of contamination into waterways. Still, the impact of chemical pollutants on sediment is less well understood, especially from an ecotoxicological perspective, even though it is known that chemicals from industrial processes are frequently released into river systems. Therefore, here we compared water-sediment samples collected in high-anthropogenic urban area and low-anthropogenic peri-urban area. We have used physicochemical parameters, genotoxicity assay, bioindication and acute and surviving chronic toxicity tests - in an integrated biological assessment. Results suggest no acute toxicity related to exposure to samples from both areas. Still, samples collected in the high-anthropogenic urban area were associated with chronic toxicity effects in D. magna. Heavy metals Pb, Cu, and Cr were found in all samples. Even having all averages below the allowed level as determined by CONAMA (Resolution 420-Class 2), the Water Quality Index (WQI) score showed us that samples from high-anthropogenic sites were identified as "Poor," and samples from low-anthropogenic sites were identified as "Good." Ephemeroptera, Plecoptera, and Odonata, which are very sensitive organisms, were largely absent in high-anthropogenic areas, showing that it is likely to be associated with WQI. Therefore, careful consideration should be applied to monitoring effluent discharges using predictive tests, considering the environmental risks of sediment contamination and its consequences on the total environment.

Arsenic exposure from groundwater: environmental contamination, human health effects, and sustainable solutions.

Arsenic (As) occurs naturally in geologic conditions, but groundwater contamination might also be found due to the consequences of mining, agricultural and industrial processes. Human exposure to As after drinking contaminated water is commonly associated with acute toxicity outcomes and chronic effects ranging from skin lesions to cancer. Integrated actions from environmental and health authorities are needed to reduce exposure, monitoring outcomes, and promotion of actions to offer sustainable As-safe water alternatives. Considering recent research trends, the present review summarizes and discusses current issues associated with the process and effects of contamination and decontamination in an environmental health perspective. Recent findings reinforce the harmful effects of the consumption of As-contaminated water and broaden the scope of related diseases including intestinal maladies, type 2 diabetes, cancers of bladder, kidneys, lung, and liver. Among the main strategies to diminish or remove As from water, the following are highlighted (1) ion exchange system and membrane filtration (micro, ultra, and nanofiltration) as physicochemical treatment systems; (2) use of cyanobacteria and algae in bioremediation programs and (3) application of nanotechnology for water treatment.

Shifts in bacterial communities and antibiotic resistance genes in surface water and gut microbiota of guppies (Poecilia reticulata) in the upper Rio Uberabinha, Brazil.

Anthropogenic activities especially water pollution can affect the diversity and composition of microbial communities and promote the spread of antibiotic resistance genes (ARGs). In this study, water samples and guppies (Poecilia reticulata) were sampled from six sampling sites along the Uberabinha River in southeastern Brazil, both microbial communities and ARGs of surface waters and intestinal microbiota of guppies (Poecilia reticulata) were detected. According to the results of 16S rRNA amplicon sequencing, Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria were dominant phyla in both water and intestinal microbiota, but the abundance of putative pathogens was higher at heavily polluted sites. Up to 83% of bacteria in intestinal microbiota originated from water microbiota; this proportion was relatively higher in less polluted compared to polluted environments. ARGs providing resistance of tetracyclines and quinolones were dominant in both water and gut microbiota. The relative abundances of class I integrons and ARGs were as high as 1.74 × 10-1/16S rRNA copies and 3.61 × 10-1/16S rRNA copies, respectively, at heavily polluted sites. Correlation analysis suggests that integrons and bacteria play key roles in explaining the widespread occurrence of ARGs in the surface, but not in intestinal microbiota. We could rule out the class I integrons a potential intermediary bridge for ARGs between both types of microbiomes. Our results highlight the tight link in microbial communities and ARGs between ambient microbiota of stream ecosystems and intestinal microbiota of fish. Our study could have far-reaching consequences for fisheries and consumer safety and calls for investigations of gut microbiota of target species of both commercial fisheries and recreational (hobby) angling.

Analysis of genotoxic effects on plants exposed to high traffic volume in urban crossing intersections.

A biological assessment of environmental quality was performed using the tropical plant species Tradescantia pallida (Rose) D.R. Hunt. var. purpurea exposed to different levels of air contamination in urban intersections with high volume of vehicle traffic. Air quality (average daily levels of particulate material in the PM1, 2.5, 10 fractions) and traffic volume in crossing intersections were monitored for 30 days before the collection of plants. Frequency of micronuclei and pollen abortivity in inflorescences collected at different intersections with gradual levels of traffic volume were evaluated as biomarkers of genotoxicity. In addition, the concentrations of bioaccumulated heavy metals in the leaves of the collected plants were also investigated. The proposed biological assessment model found a positive association between the environmental variables (traffic volume; concentration of particulate material) and biological effects (leaf concentration of Cr and Cd; micronucleus frequencies and pollen abortivity).

Low toxicity and high efficacy in use of novel approaches to control Aedes aegypti.

Arthropod-borne viruses are a group of etiologic agents accounting for different incapacitating diseases that progress to severe and lethal forms in animal and human targets consequently representing a significant burden on public health and global economies. Although attempts were undertaken to combat Aedes aegypti, the primary urban mosquito vector of several life-threatening diseases, the misuse of chemical pesticides, development of resistance, and toxicity on non-target species still need to be overcome. In this context, it is imperative for development of long-lasting, novel approaches envisioning effective control of Aedes aegypti, mainly in endemic regions. Thus, the present review was undertaken to describe safe and eco-friendly approaches as potential weapons against Aedes aegypti. Accordingly, the findings discussed indicated that biological larvicides and genetic engineering technologies constitute noteworthy alternatives of future mosquito-borne arbovirus disease control efforts.

Contamination and health risks assessment in a dam in the southeast region of Brazil using ecotoxicological methods.

Concerned with water quality, specialists have resorted to ecotoxicology as a tool to assess suspected contamination, enabling creation of strategies to repair the observed damage. Organisms such as fish and micro crustaceans are widely used in acute tests due to several characteristics in common among them including (1) accessibility of multiple samples, and (2) enhanced sensitivity when exposed to pollutants. Thus, the objective of this investigation was to determine the degree of toxicity at different points of a dam in Coromandel, Minas Gerais, using Artemia salina and Danio rerio as bioindicator organisms. Water was collected at three points of the dam were subsequently used to expose these organisms to different contaminant concentrations. Following exposure mortality and immobility rates were determined and compared to negative control (only distilled water). Results with exposure of A. salina did not present significant pollution affects. However, in the case of D. rerio the mortality frequency, immobility rate and behavioral alterations was increased at point P3; thus, D. rerio demonstrated greater sensitivity than A. salina. The physical-chemical test indicated that there were changes in parameters including biochemical demand of oxygen, dissolved oxygen and total dissolved solids (in sample at points 2 and 3), confirming toxic potential, and evidence of poor water quality at these locations. Therefore, data demonstrated that water from the dam at certain sites is not suitable for human consumption or leisure activities such as swimming that were previously reported to occur in this reservoir by the local community.

Challenges and cares to promote rational use of chloroquine and hydroxychloroquine in the management of coronavirus disease 2019 (COVID-19) pandemic: a timely review.

As a result of the 2019 coronavirus disease pandemic (COVID-19), there has been an urgent worldwide demand for treatments. Due to factors such as history of prescription for other infectious diseases, availability, and relatively low cost, the use of chloroquine (CQ) and hydroxychloroquine (HCQ) has been tested in vivo and in vitro for the ability to inhibit the causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, even though investigators noted the therapeutic potential of these drugs, it is important to consider the toxicological risks and necessary care for rational use of CQ and HCQ. This study provides information on the main toxicological and epidemiological aspects to be considered for prophylaxis or treatment of COVID-19 using CQ but mainly HCQ, which is a less toxic derivative than CQ, and was shown to produce better results in inhibiting proliferation of SARS-CoV-2 based upon preliminary tests.

Association of low concentrations of pyriproxyfen and spinosad as an environment-friendly strategy to rationalize Aedes aegypti control programs.

The association of low concentrations of pyriproxyfen and Spinosad, a naturally-occurring insecticide, was evaluated as an environment-friendly strategy to rationalize Aedes aegypti control programs by reducing larvicide consumption, saving financial costs and increasing residual effect against mosquitoes development. Firstly, the ecotoxicological parameters of the mixture was performed on non-target species Daphnia magna and the results confirmed that the low concentrations used in this larvicide mixture were not able to alter the reproductive parameters of chronically exposed microcrustaceans. In contrast, the mixture altered the behavior and development of Aedes aegypti, effectively inhibiting the emergence of adult insects for a long period. The results confirm the hypothesis that even at very low concentrations, the combination of the Spinosad and Pyriproxyfen larvicides offers an opportunity for Aedes aegypti public control programs to be more efficient.

Properties, toxicity and current applications of the biolarvicide spinosad.

Characterized as a highly valuable bioactive natural product, spinosad is a pesticide with a complex chemical structure, composed of spinosyn A and D, molecules synthesized by the actinomycete Saccharopolyspora spinosa. The larvicidal activity of spinosad was postulated to be a promising approach to combat crop pests and control species responsible to transmit mosquito-borne illness, including Aedes aegypti. Although initially deemed as relatively safe for non-target organisms and highly effective against insects and crop pests, recent studies focused on the toxicity profile detected the occurrence of side effects in different living species. Thus, the present review was undertaken to describe the properties and characteristics of spinosad. In addition to indicating potential adverse effects on living organisms, alternative uses of the biopesticide as a mixture with different compounds are provided.

Using native and invasive livebearing fishes (Poeciliidae, Teleostei) for the integrated biological assessment of pollution in urban streams.

Invasive species are increasingly replacing native species, especially in anthropogenically transformed or polluted habitats. This opens the possibility to use invasive species as indicator taxa for the biological assessment of pollution. Integrated biological assessment, however, additionally relies on the application of multiple approaches to quantify physiological or cytogenetic responses to pollution within the same focal species. This is challenging when species are restricted to either polluted or unpolluted sites. Here, we make use of a small group of neotropical livebearing fishes (family Poeciliidae) for the integrated biological assessment of water quality. Comparing urban and suburban stream sections that receive varying degrees of pollution from industrial and domestic waste waters in and around the Brazilian city of Uberlândia, we demonstrate that two members of this family may indeed serve as indicators of water pollution levels. The native species Phalloceros caudimaculatus appears to be replaced by invasive guppies (Poecilia reticulata) at heavily polluted sites. Nevertheless, we demonstrate that both species could be used for the assessment of bioaccumulation of heavy metals (Pb, Cu, and Cr). Ambient (sediment) concentrations predicted concentrations in somatic tissue across species (R2-values between 0.74 and 0.96). Moreover, we used cytogenetic methods to provide an estimate of genotoxic effects of water pollution and found pollution levels (multiple variables, condensed into principal components) to predict the occurrence of nuclear abnormalities (e.g., frequencies of micro-nucleated cells) across species (R2 between 0.69 and 0.83). The occurrence of poeciliid fishes in urban and polluted environments renders this family a prime group of focal organisms for biological water quality monitoring and assessment. Both species could be used interchangeably to assess genotoxic effects of water pollution, which may facilitate future comparative analyses over extensive geographic scales, as members of the family Poeciliidae have become invasive in tropical and subtropical regions worldwide.

Assessment of genotoxic effects on elderly populations exposed to high traffic areas: Results for supporting public health surveillance.

In urban areas with intense vehicular traffic, particulate matter in suspension, especially the fraction of particles with ultra-fine diameter, has been regarded as the main problem of chronic diseases in susceptible populations, such as the elderly. This study aimed to determine the genotoxic effects of exposure to air pollution evaluating the association between the frequencies of micronuclei (MN) and binucleated (BN) cells in exfoliated oral mucosa cells of elderly population and exposure conditions, considering the influence of traffic and concentration of PM in different aerodynamic diameters. Traffic of passenger vehicles, heavy duty trucks and environmental concentrations of Particulate Matter were measured twice a day during 28 days before biological sampling of oral mucosa from 154 participants living in areas of distinct levels of urban traffic. Data from this study showed that the group of participants living near road traffic exhibited higher MN cell frequency, when compared to the other groups of subjects. In addition, a canonical correlation analysis between environmental and genotoxicity variables analysis revealed that high concentrations of the particulate matter were correlated with intense traffic and the genotoxicity in exfoliated oral cells.

Assessment of the genotoxic potential of water courses impacted by wastewater treatment effluents using micronucleus assay in plants from the species Tradescantia.

Water pollution and the increase in genotoxic consequences in aquatic environments are well documented indicating the necessity and importance of biomonitoring programs. The objective of the present study was to determine the environmental quality of water resources and genotoxic potential of materials present within water samples obtained from the Perdizes River and the Mumbuca Stream, located in a region of discharge of wastewater treatment effluents using Tradescantia micronucleus assay (Trad - MCN). Water samples were collected from different locations up and downstream of the wastewater treatment plant during rainy season and subsequently submitted to physico-chemical analysis and Trad-MCN bioassay. The spatial distribution of the physico-chemical parameters assessed suggested that discharges of wastewater treatment effluents reduced water quality at all sites examined. Further, exposure to wastewater treatment effluents produced genotoxic effects on tetrads of Tradescantia pallida. These results reinforce the sensitivity of the Trad-MCN bioassay and its potential application in water quality monitoring programs concomitant with physicochemical evaluation.

Genotoxicity assessment of polluted urban streams using a native fish Astyanax altiparanae.

Water quality has declined globally due to increased contamination of aquatic ecosystems. The use of fish genotoxicity biomarkers may improve and complement parameters for environmental risk assessment. The aim of this study was to assess the genotoxicity of samples collected from streams of the Jordão River, a tributary of the Paranaíba River, Brazil with different levels of metal contamination, utilizing a native fish species to determine the sensitivity and viability of implementing a useful, reliable technique for routine biomonitoring programs. Chemical analysis of water and sediments collected from different sites indicated that a gradient of contamination existed as evidenced by different concentrations of metals detected. After chronic exposure to contaminated samples, micronucleus (MN) frequencies in fish erythrocytes were measured and correlation with environmental parameters determined. Sites where the water concentrations of the metals aluminum (Al), iron (Fe), manganese (Mn), zinc (Zn) and copper (Cu) were high indicating a greater genotoxic potential of these elements. At the samples collected from the urban zone, a gradual increase was found for chromium (Cr), cadmium (Cd) and nickel (Ni) indicative of adverse impacts of discharge of urban effluents. Data demonstrated that Astyanax altiparanae, used in the test, exhibited a reliable sensitivity for detection of genotoxic consequences attributed to exposure to water samples collected near the discharge of industrial and domestic waste.

Evaluation of the genotoxicity of neurotoxic insecticides using the micronucleus test in Tradescantia pallida.

Neonicotinoids and phenylpyrazoles are classes of neurotoxic insecticides which are able to bind at different ligand sites of neural receptors, leading to the deregulation of insect neural activity and hence resulting in death. The misuse or indiscriminate use of these chemicals is directly associated with several toxicological effects in biota and at different trophic levels. Based on this premise, the aim of the present study was to evaluate and compare the genotoxic capacity of different concentrations of thiamethoxam (TMX), acetamiprid (ACP), imidacloprid (IMI) and fipronil (FP) through the Micronucleus Test in Tradescantia pallida (Trad-MCN). After acclimatization (24 h), T. pallida stems were treated with stablished concentrations of TMX, ACP, IMI and FP for 8 h. Then, the stems of the model organism were submitted to a recovery phase (24 h). The young inflorescences were harvested and fixed in Carnoy solution and, after 24 h, were conserved in ethanol 70% until the analyzes. The obtained anthers were macerated on slides for microscopy, stained with acetic carmine dye and covered with coverslips before analysis by light microscopy. Considering the insecticides, the micronuclei (MN) frequency in plants treated at concentrations of 0.2 and 0.4 g L-1 for TMX, 0.2; 0.4 and 0.8 g L-1 for ACP, 0.1; 0.2; 0.4; 0.8 and 1.6 g L-1 for IMI and 0.2; 0.4; 0.8 and 1.6 g L-1 for FP differed statistically (p < 0.05, Tukey) from the MN frequency of the negative control. All chemicals evaluated revealed genotoxic activity in T. pallida at the highest concentrations.

Evaluation of toxicity and environmental safety in use of spinosad to rationalize control strategies against Aedes aegypti.

Spinosad is a naturally-occurring insecticide used for the management of Ae. aegypti larvae. The assessment of ecotoxicological parameters of spinosad is required for verifying the environmentally-friendly behavior of the compound and for evaluating toxicity values on non-target species. Thus, the aim of the study was to conduct toxicity tests using Daphnia magna as model organism after exposure to different concentrations of spinosad. Immobility effects were observed in both acute and chronic toxicity tests at the concentration of 2.5 µg/L, and D. magna exhibited an EC50-48 h of 4.1 µg/L and EC50-7d of 9.3 µg/L. Also, the reproductive test showed a significant increase in the time of first reproduction and decrease in the number of neonates per female. However, due to the rapid decay of spinosad, other reproductive parameters were not markedly affected. Thereby, considering the satisfactory control performance against Aedes aegypti, a 100-fold lower concentration of spinosad can be used against the larvae, and owing to the residual efficacy observed, the application of the pesticide in the field may be rationalized while offering environmental safety.

Effects of environmental noise pollution on perceived stress and cortisol levels in street vendors.

The present study describes and analyzes experimental results of a study performed with street vendors exposed to noise pollution by monitoring daily variations in cortisol levels taking into account the influence of variables such as age and body mass index (BMI). The study was conducted with 17 male street vendors, inhabitants of Uberlândia - Brazil, who work in the central region of the city. The levels of exposure to noise were assessed using an audio dosimeter and, every two hr, samples of saliva were collected for determination of salivary cortisol levels through an enzymatic immunoassay. The measured equivalent A-weighted sound level (LAeq) ranged from 70.2 to 76.6 dB (A) during the monitoring period of endogenous salivary cortisol levels. Morning levels of cortisol in street vendors were higher in older and overweight individuals. The noise levels to which the subjects were exposed were above the acoustic comfort threshold established by the World Health Organization and hence may be associated with severe discomfort and stress.

Genotoxic and mutagenic assessment of spinosad using bioassays with Tradescantia pallida and Drosophila melanogaster.

Spinosad (SPN) is a naturally-occurring insecticide obtained from the fermentation process of the actinomycete Saccharopolyspora spinosa. Owing to the larvicidal action, the compound has been used in the control of Aedes aegypti. As a new insecticide commercially available in the market, few data are reported on genotoxic effects in non-target organisms. The objective of the present study was to evaluate the mutagenic effect of SPN through the Micronucleus Test in Tradescantia pallida (Trad-MCN) and using the mutation and somatic recombination test in Drosophila melanogaster (SMART). At the Trad-MCN, after acclimatization (24 h), T. pallida stems were submitted to chronic treatment with SPN at concentrations of 0.156; 0.312; 0.625; 1.25 and 2.5 g/L solution for 24 h, followed by a recovery period. In SMART, considering the third stage larvae, offspring resulting from the ST and HB crossing were placed on chronic treatment (48 h) with 0.039; 0.078 and 0.156 µg/mL of SPN solution. No mutagenic effect was observed at any of the evaluated concentrations in SMART. Additionally, SPN is more toxic after metabolism via CYP6A2 (cytochrome P450) in D. melanogaster. However, SPN at the concentrations of 0.625; 1.25 and 2.5 g/L was able to induce high frequency of micronuclei in T. pallida. Under the experimental conditions of T. pallida in the present study, SPN caused genotoxic activity.

Ecotoxicological assessment of synthetic and biogenic surfactants using freshwater cladoceran species.

Surfactants have been continuously detected within aquatic environments as a consequence of their use on a global scale. Lipopeptides are biosurfactants naturally produced by Bacillus subtilis that have been explored as green alternatives. The assessment of ecotoxicological parameters of synthetic and biogenic surfactants are required for evaluating toxicity values and to verify the eco-friendly behaviour of the biological compounds. This study aimed to conduct toxicity testing for different surfactants - sodium dodecyl sulphate and Triton X-100 - and biosurfactants - surfactin, iturin and fengycin - at different concentrations using Daphnia magna as model organism and Dendrocephalus brasiliensis as alternative test species for monitoring of pollutants in tropical freshwaters. According results, both species showed high sensitivity for the anionic compound SDS concerning the recommended dosage use, exhibiting EC50-48h values of 24.1 and 15.4 mg/L for D. magna and D. brasiliensis, respectively. Although the biological source, surfactin showed the lower safety behaviour among the biogenic surfactants, while iturin and fengycin revealed very low toxicity effects on both organisms. Besides, data exhibited a higher responsiveness of D. brasiliensis for all tested compounds in comparison to D. magna, highlighting the importance of this species for monitoring of pollutants in tropical and subtropical environments.