Alterations in neurotransmitters, steroid hormones, vitellogenin, and antioxidant system induced by di-n-butyl phthalate and di-isopentyl phthalate on catfish Rhamdia quelen.

Phthalates, such as di-n-butyl phthalate (DBP) and di-isopentyl phthalate (DiPeP), are pollutants with a high potential for endocrine disruption. This study aimed to evaluate parameters of endocrine disruption in specimens of the Neotropical fish Rhamdia quelen exposed to DBP and DiPeP through their food. After 30 days of exposure, the fish were anesthetized and then euthanized, and blood, hypothalamus, liver, and gonads were collected. DBP caused statistically significant alterations in the serotoninergic system of males (5 and 25 ng/g) and females (5 ng/g) of R. quelen and it increased testosterone levels in females (25 ng/g). DiPeP significantly altered the dopaminergic system in females, reduced plasma estradiol levels (125 ng/g) and hepatic vitellogenin expression (25 ng/g), and changed the antioxidant system in gonads (125 ng/g). The results suggest that DBP and DiPeP may have different response patterns in females, with the former being androgenic and the latter being anti-estrogenic. These findings provide additional evidence regarding the molecular events involving DBP and DiPeP in the endocrine disruption potential in juvenile specimens of Rhamdia quelen.

The evaluation of skin sensitization potential of the UVCB substance diisopentyl phthalate by in silico and in vitro methods.

Diisopentyl phthalate (DiPeP) is primarily used as a plasticizer or additive within the production of polyvinyl chloride (PVC), and has many additional industrial applications. Its metabolites were recently found in urinary samples of pregnant women; thus, this substance is of concern as relates to human exposure. Depending upon the nature of the alcohol used in its synthesis, DiPeP may exist either as a mixture consisting of several branched positional isomers, or as a single defined structure. This article investigates the skin sensitization potential and immunomodulatory effects of DiPeP CAS No. 84777-06-0, which is currently marketed and classified as a UVCB substance, by in silico and in vitro methods. Our findings showed an immunomodulatory effect for DiPeP in LPS-induced THP-1 activation assay (increased CD54 expression). In silico predictions using QSAR TOOLBOX 4.5, ToxTree, and VEGA did not identify DiPeP, in the form of a discrete compound, as a skin sensitizer. The keratinocyte activation (Key Event 2 (KE2) of the adverse outcome pathway (AOP) for skin sensitization) was evaluated by two different test methods (HaCaT assay and RHE assay), and results were discordant. While the HaCaT assay showed that DiPeP can activate keratinocytes (increased levels of IL-6, IL-8, IL-1α, and ILA gene expression), in the RHE assay, DiPeP slightly increased IL-6 release. Although inconclusive for KE2, the role of DiPeP in KE3 (dendritic cell activation) was demonstrated by the increased levels of CD54 and IL-8 and TNF-α in THP-1 cells (THP-1 activation assay). Altogether, findings were inconclusive regarding the skin sensitization potential of the UVCB DiPeP-disagreeing with the results of DiPeP in the form of discrete compound (skin sensitizer by the LLNA assay). Additional studies are needed to elucidate the differences between DiPeP isomer forms, and to better understand the applicability domains of non-animal methods in identifying skin sensitization hazards of UVCB substances.

Brazilian National Network of Alternative Methods (RENAMA) 10th Anniversary: Meeting of the Associated Laboratories, May 2022.

The Brazilian National Network of Alternative Methods (RENAMA), which is linked to the Ministry of Science, Technology and Innovation, is currently comprised of 51 laboratories from CROs, academia, industry and government. RENAMA's aim is to develop and validate new approach methodologies (NAMs), as well as train researchers and disseminate information on their use - thus reducing Brazilian, and consequently Latin American, dependence on external technology. Moreover, it promotes the adoption of NAMs by educators and trained researchers, as well as the implementation of good laboratory practice (GLP) and the use of certified products. The RENAMA network started its activities in 2012, and was originally comprised of three central laboratories - the National Institute of Metrology, Quality and Technology (INMETRO); the National Institute of Quality Control in Health (INCQS); and the National Brazilian Biosciences Laboratory (LNBio) - and ten associated laboratories. In 2022, RENAMA celebrated its 10th anniversary, a milestone commemorated by the organisation of a meeting attended by different stakeholders, including the RENAMA-associated laboratories, academia, non-governmental organisations and industry. Ninety-six participants attended the meeting, held on 26 May 2022 in Balneário Camboriú, SC, Brazil, as part of the programme of the XXIII Brazilian Congress of Toxicology 2022. Significant moments of the RENAMA were remembered, and new goals and discussion themes were established. The lectures highlighted recent innovations in the toxicological sciences that have translated into the assessment of consumer product safety through the use of human-relevant NAMs instead of the use of existing animal-based approaches. The challenges and opportunities in accepting such practices for regulatory purposes were also presented and discussed.

Prediction of acute fish toxicity (AFT) and fish embryo toxicity (FET) tests by cytotoxicity assays using liver and embryo zebrafish cell lines (ZFL and ZEM2S).

Fish cell-based assays represent potential alternative methods to vertebrates' use in ecotoxicology. In this study, we evaluated the cytotoxicity of thirteen chemicals, chosen from OECD guidelines 236 and 249, in two zebrafish cell lines (ZEM2S and ZFL). We aimed to investigate whether the IC50 values obtained by viability assays (alamar blue, MTT, CFDA-AM, and neutral red) can predict the LC50 values of Acute Fish Toxicity (AFT) test and Fish Embryo Toxicity (FET) test. There was no significant difference between the values obtained by the different viability assays. ZFL strongly correlated with AFT and FET tests (R2AFT = 0.73-0.90; R2FET48h = 0.79-0.90; R2FET96h = 0.76-0.87), while ZEM2S correlated better with the FET test (48h) (R2 = 0.70-0.86) and weakly with AFT and FET tests (96h) (R2AFT = 0.68-0.74 and R2FET96h = 0.62-0.64). The predicted LC50 values allowed the correct categorization of the chemicals in 76.9% (AFT test) - 90.9% (FET test) using ZFL and in 30.7% (AFT test) - 63.6% (FET test) using ZEM2S considering the US EPA criterion for classifying acute aquatic toxicity. ZFL is a promising cell line to be used in alternative methods to adult fish and fish embryos in ecotoxicity assessments, and the method performed in 96-well plates is advantageous in promoting high-throughput cytotoxicity assessment.

An integrated in silico-in vitro investigation to assess the skin sensitization potential of 4-Octylphenol.

One of the major challenges in chemical toxicity testing is the possibility to protect human health against adverse effects with non-animal methods. In this paper, 4-Octylphenol (OP) was tested for skin sensitization and immunomodulatory effects using an integrated in silico-in vitro test approach. In silico tools (QSAR TOOLBOX 4.5, ToxTree and VEGA) were used together with several in vitro tests including HaCaT cells (quantification of IL-6; IL-8; IL-1α and IL-18 by ELISA and expression of genes TNF, IL1A, IL6 and IL8 by RT- qPCR), RHE model (quantification of IL-6; IL-8; IL-1α and IL-18 by ELISA) and THP-1 activation assay (CD86/CD54 expression and IL-8 release). Additionally, the immunomodulatory effect of OP was investigated using lncRNAs MALAT1 and NEAT1 expression and LPS-induced THP-1 activation (CD86/CD54 expression and IL-8 release). The in silico tools predicted OP as a sensitizer. In vitro tests are also concordant with the in silico prediction. OP increased IL-6 expression (HaCaT cells); IL-18 and IL-8 expressions (RHE model). An irritant potential was also shown by a great expression of IL-1α (RHE model); and increased expression of CD54 marker and IL-8 in THP-1 cells. Immunomodulatory effects of OP were demonstrated by the downregulation of NEAT1, MALAT1 (epigenetic markers), IL6 and IL8; and an increase in LPS-induced CD54 and IL-8 expressions. Overall, results indicate that OP is a skin sensitizer, being positive in three key events of the AOP for skin sensitization, also showing immunomodulatory effects.

In vitro evaluation of the inhalation toxicity of the cosmetic ingredient aluminum chlorohydrate.

Aluminum chlorohydrate (ACH) is a major aerosol component frequently used as the active ingredient in antiperspirants, and in vivo studies have raised a concern about its inhalation toxicity. Still, few studies have addressed its effects on the human respiratory tract. Therefore, we developed a study on ACH inhalation toxicity using an in vitro human alveolar cell model (A549 cells) with molecular and cellular markers of oxidative stress, immunotoxicity, and epigenetic changes. The chemical characterization of ACH suspensions indicated particle instability and aggregation; however, side-scatter analysis demonstrated significant particle uptake in cells exposed to ACH. Exposure of A549 cells to non-cytotoxic concentrations of ACH (0.25, 0.5, and 1 mg/ml) showed that ACH induced reactive oxygen species. Moreover, ACH upregulated TNF, IL6, IL8, and IL1A genes, but not the lncRNAs NEAT1 and MALAT1. Finally, no alterations on the global DNA methylation pattern (5-methylcytosine and 5-hydroxymethylcytosine) or the phosphorylation of histone H2AX (γ-H2AX) were observed. Our data suggest that ACH may induce oxidative stress and inflammation on alveolar cells, and A549 cells may be useful to identify cellular and molecular events that may be associated with adverse effects on the lungs. Still, further research is needed to ensure the inhalation safety of ACH.

Protective potential of sulfated polysaccharides from tropical seaweeds against alkylating- and oxidizing-induced genotoxicity.

Sulfated polysaccharides (SPs) from seaweeds are potential bioactive natural compounds, but their DNA protective activity is poorly explored. This article aimed to evaluate the genotoxic/antigenotoxic potentials of a sulfated heterofucan from brown seaweed Spatoglossum schröederi (Fucan A - FA) and a sulfated galactan from green seaweed Codium isthomocladum (3G4S) using in vitro Comet assay (alkaline and oxidative versions) with HepG2 cells. The antioxidant activity of these SPs was evaluated by total antioxidant capacity, radical scavenging, metal chelating, and antioxidant enzyme activity assays. Both SPs were not genotoxic. FA and 3G4S displayed strong antigenotoxic activity against oxidizing chemical (H2O2) but not against alkylating chemical (MMS). The DNA damage reduction after a pre-treatment of 72 h with these SPs was 81.42% to FA and 81.38% to 3G4S. In simultaneous exposure to FA or 3G4S with H2O2, HepG2 cells presented 48.04% and 55.41% of DNA damage reduction compared with the control, respectively. The antigenotoxicity of these SPs relates to direct antioxidant activity by blockage of the initiation step of the oxidative chain reaction. Therefore, we conclude that FA and 3G4S could be explored as functional natural compounds with antigenotoxic activity due to their great protection against oxidative DNA damage.

High Melanin Content in Melanoma Cells Contributes to Enhanced DNA Damage after Rose Bengal Photosensitization.

Melanoma is a type of tumor that originates from melanocytes. Irradiation of melanin with UVA and visible light can produce reactive oxygen species (ROS) such as singlet molecular oxygen (1 O2 ). The objective of this study was to examine DNA damage in melanoma cells (B16-F10) with different melanin contents, subjected to 1 O2 generation. To this end, we used the photosensitizer Rose Bengal acetate (RBAc) and irradiation with visible light (526 nm) (RBAc-PDT). We used the modified comet assay with the repair enzymes hOGG1 and T4 endonuclease V to detect the DNA damage associated with 8-oxo-7,8-dihydro-2'-deoxyguanosine and cyclobutane pyrimidine dimers lesions, respectively. We observed increased formation of hOGG1- and T4endoV-sensitive DNA lesions after light exposure (with or without RBAc). Furthermore, 18 h after irradiation, hOGG1-sensitive DNA lesions increased compared to that at the initial time point (0 h), which shows that a high melanin content contributes to post-irradiation formation of them, mainly via sustained oxidative stress, as confirmed by the measurement of ROS levels and activity of antioxidant enzymes. Contrastingly, the number of T4endoV-sensitive DNA lesions decreased over time (18 h). Our data indicate that in melanoma cells, a higher amount of melanin may affect DNA damage levels when subjected to RBAc-PDT.

Development of 3D cultures of zebrafish liver and embryo cell lines: a comparison of different spheroid formation methods.

Fish cell spheroids are promising 3D culture models for vertebrate replacement in ecotoxicology. However, new alternative ecotoxicological methods must be adapted for applications in industry and for regulatory purposes; such methods must be cost-effective, simple to manipulate and provide rapid results. Therefore, we compared the effectiveness of the traditional hanging drop (HD), orbital shaking (OS), and HD combined with OS (HD+OS) methods on the formation of zebrafish cell line spheroids (ZFL and ZEM2S). Time in HD (3-5 days) and different 96-well plates [flat-bottom or ultra-low attachment of round-bottom (ULA-plates)] in OS were evaluated. Easy handling, rapid spheroid formation, uniform-sized spheroids, and circularity were assessed to identify the best spheroid protocol. Traditional HD alone did not result in ZFL spheroid formation, whereas HD (5 days)+OS did. When using the OS, spheroids only formed on the ULA-plate. Both HD+OS and OS were reproducible in size (177.50 ± 2.81 µm and 225.62 ± 19.20 µm, respectively) and circularity (0.83 ± 0.02 and 0.80 ± 0.01, respectively) of ZFL spheroids. Nevertheless, HD+OS required a considerable time to completely form spheroids (10 days) and intensive handling, whereas the OS was fast (5 days of incubation) and simple. OS also yielded reproducible ZEM2S spheroids in 1 day (226.23 ± 0.57 µm diameter and 0.80 ± 0.01 circularity). In conclusion, OS in ULA-plate is an effective and simple spheroid protocol for high-throughput ecotoxicity testing. This study contributes to identify a fast, reproducible, and simple protocol of single piscine spheroid formation in 96-well plates and supports the application of fish 3D model in industry and academia.

A review of the success and challenges in characterizing human dermal exposure to flame retardants.

Since organic flame retardants (FRs) have several industrial applications, they have been largely detected in environmental and biological samples, and humans have been highly exposed to them. Although the effects of oral and inhaled FRs have been well studied, dermal exposure to them has only recently been pointed out as a potential route of human exposure. Consequently, the effects of FRs on the skin and secondary target organs have been poorly investigated. This review article summarizes the main findings regarding dermal exposure to FRs, points the limitation of the published studies, and suggests future perspectives for better understanding of how dermal exposure to FRs impacts the human health. This review lists some gaps that must be filled in future studies, including characterization of the bioavailable fraction and assessment of exposure for new FRs, to establish their physiological significance and to improve the development of 3D dermal tissue for more reliable results to be obtained.

Single and mixture toxicity evaluation of three phenolic compounds to the terrestrial ecosystem.

Endocrine-disrupting chemicals (EDCs) are primarily studied regarding endocrine-mediated effects in mammals and fish. However, EDCs can cause toxicity by mechanisms outside the endocrine system, and, as they are released continuously into soils, they may pose risks to terrestrial organisms. In this work, the plant Allium cepa and the earthworm Eisenia foetida were used as test systems to evaluate the toxicity and cyto-/geno-toxicity of three environmental phenols known as EDCs (Bisphenol A - BPA, Octylphenol - OP, Nonylphenol - NP). The tested phenols were evaluated in environmentally relevant concentrations (µg/L) and in single forms and mixture. BPA, OP, and NP did not inhibit the seed germination and root development in A. cepa in their single forms and mixture. However, all single forms of the tested phenols caused cellular and DNA damages in A. cepa, and although these effects persist in the mixtures, the effects were verified at lower levels. These phenols caused acute toxicity to E. foetida after 48 h of exposure and at both conditions evaluated (single forms and mixture); however, unlike A. cepa, in earthworms, mixtures and single forms presented the same level of effects, indicating that interspecies physiological different might influence the mixture toxicity. In summary, our results suggest that BPA, OP, and NP are toxicants to earthworm and cyto-/geno-toxicants to monocotyledonous plants at low concentrations. However, interaction among these phenols reduces the magnitude of their individual effects (antagonistic effect) in the plant test system. Therefore, this study draws attention to the need to raise knowledge about the ecotoxicity of phenolic compounds to help predict their ecological risks and protect non-target terrestrial species.

Safety aspects of kraft lignin fractions: Discussions on the in chemico antioxidant activity and the induction of oxidative stress on a cell-based in vitro model.

Lignin is a complex phenolic biopolymer present in plant cell walls and a by-product of the cellulose pulping industry. Lignin has functional properties, such as antioxidant activity, that make it a potential natural active ingredient for health-care products. However, not all safety aspects of lignin fractions have been adequately investigated. Herein, we evaluated the antioxidant and genotoxic potential of two hardwood kraft lignins (F3 and F5). The chemical characterization of F3 and F5 demonstrated their thermal stability and the presence of different phenolic units, while the DPPH assay confirmed the antioxidant activity of these lignin fractions. Despite being antioxidants in the DPPH assay, F3 and F5 were capable of generating intracellular reactive oxygen species (ROS) and subsequently causing oxidative DNA damage (Comet assay) in HepG2 cells. The biological relevance of the DPPH assay might be uncertain in some cases; therefore, we suggest combining in chemico tests with biological system-based tests to determine efficacy and safety levels of lignins and define appropriate applications of lignins for consumer products. Moreover, kraft lignins obtained by acid precipitation may pose risks to human health; however, as genotoxicity is not the sole endpoint of toxicity required in hazard assessments, additional toxicological evaluations are needed.

Thymol-Loaded Biogenic Silica Nanoparticles in an Aquatic Environment: The Impact of Particle Aggregation on Ecotoxicity.

Thymol, a monoterpene phenol, is used as a natural biocide. To circumvent its chemical instability, we propose use of thymol-loaded biogenic silica nanoparticles (BSiO2 #THY NPs); however, the toxicity of this system for aquatic organisms is unknown. Thus, the present study aimed to evaluate the toxicogenetic effects induced by thymol, BSiO2 NP, and BSiO2 #THY on Artemia salina and zebrafish (Danio rerio) early life stages. We also investigated the impact of BSiO2 aggregation in different exposure media (saline and freshwater). Based on the median lethal concentration at 48 h (LC5048h ), BSiO2 #THY (LC5048h = 1.06 mg/L) presented similar toxic potential as thymol (LC5048h = 1.03 mg/L) for A. salina, showing that BSiO2 had no influence on BSiO2 #THY toxicity. Because BSiO2 aggregated and sedimented faster in A. salina aqueous medium than in the other medium, this NP had lower interaction with this microcrustacean. Thus, BSiO2 #THY toxicity for A. salina is probably due to the intrinsic toxicity of thymol. For zebrafish early life stages, BSiO2 #THY (LC5096h = 13.13 mg/L) was more toxic than free thymol (LC5096h = 25.60 mg/L); however, BSiO2 NP has no toxicity for zebrafish early life stages. The lower aggregation of BSiO2 in the freshwater medium compared to the saline medium may have enhanced thymol's availability for this aquatic organism. Also, BSiO2 #THY significantly induced sublethal effects as thymol, and both were genotoxic for zebrafish. In conclusion, although BSiO2 #THY still needs improvements to ensure its safety for freshwater ecosystems, BSiO2 NP seems to be a safe nanocarrier for agriculture. Environ Toxicol Chem 2021;40:333-341. © 2020 SETAC.

Genotoxicity of titanium dioxide nanoparticles and triggering of defense mechanisms in Allium cepa.

Titanium dioxide nanoparticles (TiO2NPs) are widely used and may impact the environment. Thus, this study used a high concentration of TiO2NP (1000 mg/L) to verify the defense mechanisms triggered by a plant system - an indicator of toxicity. Furthermore, this study aimed at completely characterizing TiO2NP suspensions to elucidate their toxic behavior. TiO2NPs were taken up by meristematic cells of Allium cepa, leading to slight inhibition of seed germination and root growth. However, severe cellular and DNA damages were observed in a concentration-dependent manner (10, 100, and 1000 mg/L). For this reason, we used the highest tested concentration (1000 mg/L) to verify if the plant cells developed defense mechanisms against the TiO2NPs and evaluated other evidences of TiO2NP genotoxicity. Nucleolar alterations and plant defense responses (i.e., increased lytic vacuoles, oil bodies and NP phase change) were observed in meristematic cells exposed to TiO2NP at 1000 mg/L. In summary, TiO2NPs can damage the genetic material of plants; however, plants displayed defense mechanisms against the deleterious effects of these NPs. In addition, A. cepa was found to be a suitable test system to evaluate the cyto- and genotoxicity of NPs.

Toxicological evaluation of nail polish waste discarded in the environment.

Nail polish has been widely used around the world. However, the hazards of nail polishes discarded in the environment are still poorly investigated. Thus, the toxicogenetic effects of solubilized (SE) and leached (LE) extracts from nail polishes were investigated, simulating their disposal on water and landfill, respectively, and identifying their physicochemical properties and chemical constituents. Organic compounds and metals were detected in both extracts. SE and LE only induced mutagenic effects in TA98 Salmonella strain in the presence and absence of exogenous metabolic activation. Although both extracts did not significantly increase the frequency of micronucleated HepG2 cells, the cell viability was affected by 24-h exposure. No DNA damage was observed in gonad fish cells (RTG-2) exposed to both extracts; however, the highest SE and LE concentrations induced significant lethal and sublethal effects on zebrafish early-life stages during 96-h exposure. Based on our findings, it can be concluded that if nail polishes enter aquatic systems, it may cause negative impacts to the environment.

Mesotrione herbicide does not cause genotoxicity, but modulates the genotoxic effects of Atrazine when assessed in mixture using a plant test system (Allium cepa).

Mesotrione (MES) is an herbicide from the triketone family and has been used as an alternative to Atrazine (ATZ), which was banned in some countries due to its toxicity to non-target organisms. Despite being considered an eco-friendly herbicide, data from the literature about the harmful effects of MES in its pure form and/or in combination with other herbicides is still scarce. Aimed at assessing the potential of MES to induce cell death and DNA damage, seeds of Allium cepa (higher plant, monocotyledon) were exposed to this herbicide, pure and in mixture with ATZ, and the number of dividing cells (cytotoxicity), chromosomal aberrations (CA, genotoxicity) and micronuclei (MN, mutagenicity) were then quantified. The pure MES (1.8 to 460 µg/L) did not show either cytotoxicity or genotoxicity/mutagenicity under the tested conditions. The genotoxicity of ATZ (1.5 to 400 µg/L), previous reported in the literature, was confirmed herein. The assessment of MES + ATZ mixtures (1.8 + 1.5; 7 + 6.25; 30 + 25 µg/L, respectively) showed that MES, at low concentrations, enhance the genotoxicity of ATZ (potentiation), since the significant frequencies of CA and MN were greater than the ones expected in additive effects. Taking together, MES in its pure form seems to be a safe alternative to ATZ regarding the capacity to damage (at cellular and DNA levels) non-target plants (Monocots); however, MES in combination with ATZ appeared to act as a co-mutagen at low concentrations.

In vitro characterization of cutaneous immunotoxicity of immortalized human keratinocytes (HaCaT) exposed to reactive and disperse textile dyes.

Several synthetic dyes are used by textile industry for supplying the market of colored clothes. However, these chemicals have been associated with a variety of adverse human health effects, including textile dermatitis. Thus, there is a growing concern to identify textile dyes potentially as skin immunotoxicants. The aim of this in vitro study was to characterize the immunotoxic potential of reactive (Reactive Green 19 [RG19], Reactive Blue 2 [RB2], Reactive Black 5 [RB5]) and disperse (Disperse Red 1 [DR1]) textile dyes using a dermal cell line. For this purpose, a cell-based approach was conducted with immortalized human keratinocytes (KC) (HaCaT) using selected biomarkers of cutaneous inflammation including modulation of matrix metalloproteinases (MMP), oxidative stress such as reactive oxygen species (ROS) generation, and inflammatory cytokine profile. DR1 was the only dye able to trigger an immune response such as release of IL-12 cytokine, a potent co-stimulator of T helper 1 cell, which may be considered as a skin immunotoxicant. The reactive dyes including RB5 that were previously reported as skin sensitizers failed to induce inflammatory reactions under the conditions tested. The reactive dyes studied may pose a risk to human KC by induction of effects related to modulation of MMP-2 (RB5) and -9 (RB5 and RB2) and generation of ROS (RG19 and RB2). Thus, all these dyes need to be used with caution to avoid undesirable effects to consumers who may be exposed dermally.

Eco- and genotoxicological assessments of two reactive textile dyes.

Contamination of natural waters has been one of the major problems of modern society and the textile industry is rated as an important polluting source, due to the generation of large amounts of wastewaters. The aim of this study was to assess textile dyes Reactive Blue 19 (RB19, anthraquinone dye) and Reactive Red 120 (RR120, azo dye) in terms of the potential to induce adverse effects on aquatic organisms and humans. Thus, these dyes were tested using the following assays: Microtox assay (Vibrio fischeri); brine shrimp (Artemia salina); Daphnia similis; and Comet with normal human dermal fibroblasts as well as Ames test (TA98, TA100, YG1041, YG1042--with and without S9). RB19 was relatively nontoxic to all aquatic bioindicators analyzed with an EC50 of more than 100 mg/L, whereas RR120 was only moderately toxic to A. salina with a EC50-48h of 81.89 mg/L. Mutagenicity through base pair substitution was observed with RB19 in the presence of S9 (Ames-positive). The comet assay did not demonstrate any apparent genotoxic effects for any tested dye. Although mutagenicity was detected with RB19, the mutagenic effect observed may be considered weak compared to the ability to induce DNA damage by other classes of dyes such as disperse dyes. Therefore, these dyes may be classified as nonmutagens (RR120) or weak mutagens (RB19) and relatively nontoxic for aquatic organisms. However, it is noteworthy that the weak acute toxicity to A. salina induced by RR120 is sufficient to suggest potential damage to the aquatic ecosystem and emphasizes the need for biomonitoring dye levels in wastewater systems.

Genotoxicity assessment of reactive and disperse textile dyes using human dermal equivalent (3D cell culture system).

Thousands of dyes are marketed daily for different purposes, including textile dyeing. However, there are several studies reporting attributing to dyes deleterious human effects such as DNA damage. Humans may be exposed to toxic dyes through either ingestion of contaminated waters or dermal contact with colored garments. With respect to dermal exposure, human skin equivalents are promising tools to assess in vitro genotoxicity of dermally applied chemicals using a three-dimensional (3D) model to mimic tissue behavior. This study investigated the sensitivity of an in-house human dermal equivalent (DE) for detecting genotoxicity of textile dyes. Two azo (reactive green 19 [RG19] and disperse red 1[DR1]) dyes and one anthraquinone (reactive blue 2 [RB2]) dye were analyzed. RG19 was genotoxic for DE in a dose-responsive manner, whereas RB2 and DR1 were nongenotoxic under the conditions tested. These findings are not in agreement with previous genotoxicological assessment of these dyes carried out using two-dimensional (2D) cell cultures, which showed that DR1 was genotoxic in human hepatoma cells (HepG2) and RG19 was nongenotoxic for normal human dermal fibroblasts (NHDF). These discrepant results probably may be due to differences between metabolic activities of each cell type (organ-specific genotoxicity, HepG2 and fibroblasts) and the test setup systems used in each study (fibroblasts cultured at 2D and three-dimensional [3D] culture systems). Genotoxicological assessment of textile dyes in context of organ-specific genotoxicity and using in vitro models that more closely resemble in vivo tissue architecture and physiology may provide more reliable estimates of genotoxic potential of these chemicals.

An overview of biodiesel soil pollution: data based on cytotoxicity and genotoxicity assessments.

Biodiesel production has received considerable attention in the recent past as a nonpolluting fuel. However, this assertion has been based on its biodegradability and reduction in exhaust emissions. Assessments of water and soil biodiesel pollution are still limited. Spill simulation with biodiesel and their diesel blends in soils were carried out, aiming at analyzing their cytotoxic and genotoxic potentials. While the cytotoxicity observed may be related to diesel contaminants, the genotoxic and mutagenic effects can be ascribed to biodiesel pollutants. Thus, taking into account that our data stressed harmful effects on organisms exposed to biodiesel-polluted soils, the designation of this biofuel as an environmental-friendly fuel should be carefully reviewed to assure environmental quality.