Increasing scientific attention on the presence of micro- and nanoplastics (MNPs) in the environments and their potential toxic effects on humans and the ecosystems is evident. Accordingly, the ...number of publications on this topic has increased substantially from only 5 in 2010 to more than 850 in 2019. Thus, this critical review aimed at providing state-of-the-art information on the existing methods for characterization and detection of MNPs in various matrices, as well as the reported toxic effects of MNPs in both in vivo and in vitro systems, anticipating challenges and providing future needs to improve the current scientific knowledge. We performed a systematic search of recent literature on available methodologies for the characterization/detection of MNPs in different samples, and the summary of such protocols is provided. Also, the existing procedures for in vitro and in vivo toxicity evaluation of MNPs were critically described. The results of our search revealed that quite a great deal of effort had been made to detect, characterize, and quantify the fate and effect of MNPs. However, we are still far from a complete understanding of behaviors of MNPs in the environments and biological systems. Thus, there is a need to advance the existing protocols to improve data accuracy. Besides, more studies that focus on uptake kinetics, accumulation, and biodistribution of MNPs in biological systems are required.
●The state-of-the-art on the methods for characterization and detection of micro- and nanoplastics (MNPs) is presented.●Lack of validated methodology for MNPs determination/characterization.●Toxic effects of MNPs in both in vivo and in vitro systems were revised.●An understanding of behaviors of MNPs in the environments and biological systems is still limited.●More studies on uptake kinetics, accumulation, and biodistribution of MNPs in biological systems are required.
The increase and indiscriminate use of personal care products, food products, fertilizers, pesticides, and health products, among others, have resulted/are resulting in extensive environmental ...contamination. Most of these products contain traces of widespread chemicals, usually known as emerging pollutants (EPs) or pollutants of emerging concern (PEC). The Latin American (LA) region comprises 20 countries with different social and cultural aspects, with 81 % of the population living in urban areas. The LA region has some countries on the top list of users/consumers of EPs, from pesticides and fertilizers to personal care products. However, there is a gap in information related to the distribution of EPs in the environment of this region, with very few existing review texts exploring this issue. Therefore, this present paper advances this approach. An exhaustive literature review, with the selection of 176 documents, provided unique up-to-date information on the presence/distribution of 17 classes of legacy or emerging pollutants in different food and environmental matrices (soil, sediment, water, and air). The study shows that the wide distribution and recorded levels of these pollutants in the continental environment are potential risks to human health, mainly through food and drinking water ingestion. Polycyclic aromatic hydrocarbons are pollutants of deep public concern since they show carcinogenic properties. Several classes of pollutants, like endocrine disruptors, have caused harmful effects on humans and the environment. Besides that, pharmaceutical products and pesticides are compounds of high consumption worldwide, being environmental contamination a real and ongoing possibility. Finally, gaps and future research needs are deeply pointed out.
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•Brazil has the higher number of articles in LA, corresponding to 45 % of the total.•PAHs are the major group of anthropogenic environmental pollutants studied in Brazil.•Pesticides and pharmaceutical compounds are the prevalent EPs in water samples.•There are still gaps in Latin America's PFAS, EDCs, and illicit drug studies.•The lack of analytical instrumentation limits many countries from getting data on EPs.
The impacts of bacterial infection on cultivated fish species, African catfish, were investigated using oxidative stress biomarkers lipid peroxidation (LPO) and protein carbonylation and the ...activities of important antioxidant/detoxifying enzymes catalase and glutathione S-transferase (GST). Fish were inoculated via oral gavage with one of the following treatments: 1 × 10⁵ CFU/ml of Escherichia coli (EC1), 2 × 10⁵ CFU/ml of E. coli (EC2), 1 × 10⁵ CFU/ml of Vibrio fischeri (V1), 2 × 10⁵ CFU/ml of V. fischeri (V2), gavaged with distilled water and not gavaged. Fish were maintained in the laboratory for 7 days after the bacterial inoculation, and the levels of LPO, protein carbonylation, GST, and catalase activities were determined in the muscle, gills, and liver of fish. Fish inoculated with bacteria (either E. coli or V. fischeri) had a significant higher levels of tissue LPO, protein carbonylation, and GST activities in a tissue-specific pattern (liver > muscle > gills). This appears to be related with the levels of bacterial inoculation, with effects more pronounced in fish inoculated with either EC2 or V2. The catalase activity did not differ significantly between the inoculated and fish that were not inoculated. The results of this study indicate that bacterial inoculation could result in oxidative stress in fish, and liver has a higher rate of oxidative stress per mg tissue compared to the gills and the muscle.
Arsenic (As), cadmium (Cd), and mercury (Hg) are toxic elements widely distributed in the environment. Exposure to these elements was attributed to produce several acute and chronic illnesses ...including hypertension. The aim of this review is to provide a summary of the most frequently proposed mechanisms underlying hypertension associated with As, Cd, and Hg exposure including: oxidative stress, impaired nitric oxide (NO) signaling, modified vascular response to neurotransmitters and disturbed vascular muscle Ca
2+
signaling, renal damage, and interference with the renin-angiotensin system. Due to the complexity of the vascular system, a combination rather than a singular mechanism needs to be considered. In addition, epidemiological findings showing the relationship between various biomarkers of metal exposure and hypertension are described. Given the complex etiology of hypertension, further epidemiological studies evaluating the roles of confounding factors such as age, gender, and life style are still necessary.
Agrochemicals including cypermethrin (cyp) and thiourea are increasingly being applied in modern agriculture, for pest control and to improve crop yield. However, their usage often results in serious ...environmental concerns. In this study, juvenile African catfish
Clarias gariepinus
(Burchell 1822) were exposed to 50 µg/L cyp, 100 µg/L cyp, 0.05% thiourea, 50 µg/L cyp + 0.05% thiourea or 100 µg/L cyp + 0.05% thiourea, in a static renewal for 3 weeks, after which the fish were sacrificed, and the level of reduced glutathione and activities of acid phosphatase, alkaline phosphatase, amylase, protease and lipase were determined in the liver or intestinal homogenates. Also, the histopathology of some sections of the intestine was performed. The control fish were maintained in uncontaminated water (i.e. not exposed to cypermethrin or thiourea). The individual exposure of fish to cypermethrin and thiourea resulted in a significant decrease in the levels of GSH and the activities of most of the enzymes. These effects were more pronounced in fish that were exposed to cypermethrin and thiourea under a co-exposure scenario. The histological analyses of some sections of the intestine also revealed the toxicological effect of these agrochemicals, and their use led to visible intestinal pathologies such as severe erosion of the mucosa layer, faded lamina propria and disintegration of the muscle layer. The results of this study demonstrate that both cypermethrin and thiourea can alter the redox status and nutritional physiology of fish. The greater toxic effects of cypermethrin and thiourea under the co-exposure condition reiterated the potential for interactions and synergistic relationship among toxicants.
Arsenic and atrazine are common environmental contaminants probably due to their extensive use as pesticides on agricultural farmlands. In this study, zebrafish embryos were exposed to 0.8mM arsenic, ...0.1mM atrazine or mixture of both for 96h, and various indices which are indicative of teratogenicity (egg coagulation, growth retardation, edema formation, hatching success, scoliosis), genotoxicity (DNA tail moments) and oxidative stress (lipid peroxidation and reduced glutathione (GSH) levels, catalase and glutathione peroxidase activities) were determined. The negative control were exposed to 0.5% DMSO while the positive control group were exposed to 4mg/L 3,4 dichloroaniline. Egg coagulation was highest in the positive control (85%), followed by the group that was exposed to mixture of arsenic and atrazine (30%) and least in the arsenic-exposed group (20%). The incidences of edema (59%) and growth retardation (35.2%) were more frequent in the group that was exposed to contaminant mixture and least in atrazine-exposed group where incidences of both edema and growth retardation were 15%. The incidence of scoliosis ranged between 20% in arsenic-exposed group and 10% in atrazine-exposed group. Hatching success was generally high in all the groups ranging between 95% in atrazine-exposed group and 88% in the group that was exposed to mixture of arsenic and atrazine. There was no evidence of teratogenic effect in the negative control group. DNA tail moments and lipid peroxidation levels increased significantly while GSH levels and catalase activity decreased significantly in contaminant-exposed groups, especially the mixture compared to the negative control. There was no significant change in GPx activity in the exposed groups compared to the negative control. The results of this study demonstrate that both arsenic and atrazine are potentially teratogenic and genotoxic, and can cause oxidative stress in zebrafish embryos, and these effects are potentiated by toxic interactions between the two contaminants.
Polycyclic aromatic hydrocarbons (PAHs) are legacy pollutants of considerable public health concern. Polycyclic aromatic hydrocarbons arise from natural and anthropogenic sources and are ubiquitously ...present in the environment. Several PAHs are highly toxic to humans with associated carcinogenic and mutagenic properties. Further, more severe harmful effects on human- and environmental health have been attributed to the presence of high molecular weight (HMW) PAHs, that is PAHs with molecular mass greater than 300 Da. However, more research has been conducted using low molecular weight (LMW) PAHs). In addition, no HMW PAHs are on the priority pollutants list of the United States Environmental Protection Agency (US EPA), which is limited to only 16 PAHs. However, limited analytical methodologies for separating and determining HMW PAHs and their potential isomers and lack of readily available commercial standards make research with these compounds challenging. Since most of the PAH kinetic data originate from animal studies, our understanding of the effects of PAHs on humans is still minimal. In addition, current knowledge of toxic effects after exposure to PAHs may be underrepresented since most investigations focused on exposure to a single PAH. Currently, information on PAH mixtures is limited. Thus, this review aims to critically assess the current knowledge of PAH chemical properties, their kinetic disposition, and toxicity to humans. Further, future research needs to improve and provide the missing information and minimize PAH exposure to humans.
Due to the increasing population worldwide, in recent years, an exponential increase in agricultural practices has occurred in order to attend to the growing demand for food. Unfortunately, this ...increase is not associated with the supply of foodstuffs free of environmental pollutants. In Brazil, agriculture is one of the most important economic pillars, making the country one of the largest consumers of pesticides around the world. The intense use of pesticides, mainly glyphosate, 2,4-D, and atrazine, constitutes an essential factor in the viability of this great agricultural productivity. Sugarcane, corn, soybean, and citrus crops consume around 66% of the total pesticides worldwide, representing 76% of the planted area. Pesticide residues have been frequently detected in food and the environment, becoming a significant concern for human health. Monitoring programs for pesticide use are essential to reduce the potential negative impacts on the environment and improve the overall efficiency and sustainability of their use. However, in Brazil, the approval status of pesticide-active ingredients is very discrepant compared to other agricultural countries. Moreover, the duality of benefits and risks of pesticide application creates an economic and toxicological conflict. In this paper, we have critically reviewed the duality of risks-benefits of the use of pesticides in agriculture and the current Brazilian legislation issues. We have also compared this flawed legislation with other countries with high economic potential. Due to the negative environmental impacts on soil and water by the high levels of pesticides, remediation techniques, sustainable agriculture, and the development of new technologies can be considered some viable alternatives to reduce the levels in these compartments. Besides, this paper includes some recommendations that can be included in the coming years.
Tetragonal Cu2SnS3 and orthorhombic Cu4SnS4 nanocubes were synthesized by a heat up procedure with oleylamine (OLA) and dodecanethiol (DT) acting as both solvent and capping ligands. Both ...mohite–anorthic and monoclinic phases were obtained from the same variant of precursors mixture, by hot injection synthesis, at 200 and 250 °C. Changing the reaction conditions also leads to the formation of different morphologies. When OLA was used as a solvent, nanosheets or nanocubes were obtained, while the reaction with DT resulted in the formation of particles in the form of nanohexagons. The growth process of copper tin sulphide starts with the formation of Cu+ seeds, followed by the oxidation of Sn2+ to Sn4+. Dodecanethiol was an additional source of sulphur. The overall reaction leads to the formation of either phase pure Cu2SnS3 or Cu4SnS4, depending on the reaction conditions, with band-gap energies of 1.05–1.45 eV, which are in the optimum range for photovoltaic applications.
The increasing application of nanomaterials in various fields such as drug delivery, cosmetics, disease detection, cancer treatment, food preservation etc. has resulted in high levels of engineered ...nanoparticles in the environment, thus leading to higher possibility of direct or indirect interactions between these particles and biological systems. In this study, the toxic effects of three commercially available nanomaterials; copper oxide nanoparticles, copper-iron oxide nanopowders and carbon nanopowders were determined in the human hepatoma HepG2 cells using various toxicological assays which are indicative of cytotoxicity (MTT and neutral red assays), mutagenicity (cytokinesis-block micronucleus assay), oxidative stress (total reactive oxygen species and superoxide anion production) and mitochondrial impairment (cellular oxygen consumption). There was increased cytotoxicity, mutagenicity, and mitochondrial impairment in the cells treated with higher concentrations of the nanomaterials, especially the copper oxide nanoparticles. The fold production of reactive oxygen species was similar at the concentrations tested in this study but longer exposure duration resulted in production of more superoxide anions. The results of this study showed that copper oxide nanoparticles are highly toxic to the human HepG2 cells, thus implying that the liver is a target organ in human for copper oxide nanoparticles toxicity.
•Wide applications of nanomaterials have led to their high levels in the environment.•Toxicological assays are required to determine their toxic effects.•CuO NPs, CuFe2O3 NPs and C-NPs were screened for their toxicities against HepG2 cells.•CuO NPs are highly toxic to human HepG2 cells.
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