The uses of zebrafish (Danio rerio) as an in vivo model for toxicological studies: A review based on bibliometrics

An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.

Toxicity test profile for deep eutectic solvents: A detailed review and future prospects

Deep eutectic solvents (DESs) are preferable in terms of starting materials, storage and synthesis, simplicity, and component material affordability. In several industries ranging from chemical, electrochemical, biological, biotechnology, material science, etc., DES has demonstrated remarkable potential. Despite all these accomplishments, the safety issue with DES must be adequately addressed. Different DES interacts with the cellular membranes differently. It is not possible to classify all DES as easily biodegradable. By expanding the current understanding of the toxicity and biodegradation of DES, interactions between organisms and cellular membranes can be linked. The DES toxicity profile varies according to their concentration, the nature of the individual components, and how they interact with living things. Therefore, the results of this review can serve as a baseline for DES development in the future.

Acute poisoning by chlorpyrifos differentially impacts survival and cardiorespiratory function in normotensive and hypertensive rats

Hypertension is the most important and well-known risk factor for cardiovascular disease (CVD). Recently, acute organophosphate (OP) poisoning has also been pointed as a CVD risk factor. Despite this evidence, no studies have contrasted the acute toxicosis and cardiovascular (CV) effects of OP poisoning under conditions of normotension and hypertension. In this work, adult male normotensive Wistar and Spontaneously Hypertensive rats (SHR) were intraperitoneally injected with saline or chlorpyrifos (CPF), an OP compound, monitored for acute toxicosis signs and 24-h survival. After poisoning, blood pressure, heart rate and ventilation were recorded, the Bezold-Jarisch Reflex (BJR), the Chemoreflex (CR) were chemically activated, as well as the cardiac autonomic tone (AUT) was assessed. Erythrocyte and brainstem acetylcholinesterase and plasmatic butyrylcholinesterase (BuChE) activities were measured as well as lipid peroxidation, advanced oxidation protein products (AOPP), nitrite/nitrate levels, expression of catalase, TNFα and angiotensin-I converting enzyme (ACE-1) within the brainstem. CPF induced a much more pronounced acute toxicosis and 33 % lethality in SHR. CPF poisoning impaired ventilation in SHR, the BJR reflex responses in Wistar rats, and the chemoreflex tachypneic response in both strains. CPF inhibited activity of cholinesterases in both strains, increased AOPP and nitrite/nitrate levels and expression of TNFα and ACE-1 in the brainstem of Wistar rats. Interestingly, SHR presented a reduced intrinsic BuChE activity, an important bioscavenger. Our findings show that, CPF at sublethal doses in normotensive rats lead to lethality and much more pronounced acute toxicity signs in the SHR. We also showed that cardiorespiratory reflexes were differentially impacted after CPF poisoning in both strains and that the cardiorespiratory disfunction seems to be associated with interference in cholinergic transmission, oxidative stress and inflammation. These results points to an increased susceptibility to acute toxicosis in hypertension, which may impose a significant risk to vulnerable populations.

Reversible and monitorable nephrotoxicity in rats by the novel potent transcriptional enhanced associate domain (TEAD) inhibitor, K-975

The Hippo pathway plays an important role in the growth, development, and regeneration of cells and organs. Transcriptional enhanced associate domain (TEAD), a transcription activator of the Hippo pathway, forms the complex with a transcriptional coactivator yes-associated protein (YAP) or a transcriptional coactivator PDZ-binding motif (TAZ). Their excessive activations are involved in carcinogenesis such as malignant pleural mesothelioma (MPM), and thus inhibition of the TEAD complex is expected to have potent anticancer activity against MPM. On the other hand, YAP or TAZ conditional knockout mice have been reported to show abnormal findings in various tissues, including the kidney, liver, and lung. In the present study, we evaluated the systemic toxicity of K-975, a novel TEAD inhibitor, in rats. When K-975 was administered orally to rats for 1 week, proteinuria suggestive of nephrotoxicity was observed. Electron microscopy revealed that K-975 at 300 mg/kg induced glomerular podocyte foot process effacement. After a 2-week recovery period, proteinuria with foot process effacement was recovered completely. Urinalysis and urinary biomarker evaluation suggested that the urinary albumin index (urinary albumin/urinary creatinine) was the most sensitive marker for detecting K-975-induced nephrotoxicity. After 3 cycles of 1-week administration followed by 2-week recovery periods, nephrotoxicity was reversible; however, incomplete reversibility was observed in rats with severe proteinuria. In conclusion, this study revealed that in rats, oral K-975 treatment induced severe proteinuria by podocyte foot process effacement, which was reversible and monitorable by the urinary albumin index, suggesting important information for developing K-975 as an anticancer drug.

Environmental exposure and ecological risk of perfluorinated substances (PFASs) in the Shaying River Basin, China

There have been concerns raised about the environmental effects of perfluoroalkyl substances (PFASs) because of their toxicity, widespread distribution, and persistence. Understanding the occurrences and ecological risk posed by PFASs is essential, especially for the short-chain replacements perfluorobutanoic acid (PFBA) and perfluorobutane sulfonic acid (PFBS), which are now becoming predominant PFASs. The lack of aquatic life criteria (ALC), however, prevents an accurate assessment of the ecological risks of PFBA and PFBS. This study thus investigated the occurrence of 15 PFASs at 29 sampling sites in Shaying River Basin (in China) systematically, conducted the toxicity tests of PFBA and PFBS on eight resident aquatic organisms in China, and derived the predicted non-effect concentration (PNEC) values for PFBA and PFBS for two environmental media in China. The results showed that the total PFASs concentrations (ΣPFASs) ranged from 5.07 to 20.32 ng/L (average of 10.95 ng/L) in surface water, whereas in sediment, ΣPFASs ranged from 6.46 to 20.05 ng/g (dw) (average of 11.51 ng/g). The presence of PFBS was the most prominent PFASs in both water (0.372-8.194 ng/L) and sediment (4.54-15.72 ng/g), demonstrating that short-chain substitution effects can be observed in watersheds. The PNEC values for freshwater and sediment were 6.60 mg/L and 8.30 mg/kg (ww), respectively, for PFBA, and 14.04 mg/L, 37.08 mg/kg (ww), respectively, for PFBS. Ecological risk assessment of two long-chain PFASs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), and two short-chain PFASs, PFBA and PFBS, using the hazard quotient method revealed that Shaying River and other major River Basins in China were at risk of PFOS contamination. This study contributes to a better understanding of the presence and risk of PFASs in the Shaying River and first proposes the ALCs for PFBA and PFBS in China, which could provide important reference information for water quality standards.

Evaluating ecotoxicological assays for comprehensive risk assessment of toxic metals present in industrial wastewaters in the Republic of Korea

Toxicity tests represent a rapid, user-friendly and cost-effective means to assess the impact of wastewater quality on aquatic ecosystems. There are not many cases where wastewater management standards are set based on various bio-based ecotoxicity values. Here, we tested a novel multitaxon approach to compare standard water quality indices to toxicity metrics obtained from ecotoxicity tests, conducted using aquatic organisms representing several trophic levels (Aliivibrio, Ulva, Daphnia, and Lemna), for 99 industrial wastewater samples from South Korea. For five wastewater samples, the concentrations of Se, Zn, or Ni exceeded the permissible limits (1, 5, and 3 mg L^-1, respectively). All the four physiochemical water quality indices tested were positively correlated with Se and Pb concentrations. The toxicity unit (TU) scores indicated a declining sensitivity to pollutants, in the order Lemna (2.87) >Daphnia (2.24) >Aliivibrio (1.78) >Ulva (1.42). Significant correlations were observed between (1) Cd and Ni, and Aliivibrio, (2) Cu and Daphnia, (3) Cd, Cu, Zn, and Cr and Lemna, and (4) Cu, Zn, and Ni and Ulva. Daphnia-Lemna and Lemna-Ulva were found to be good indicators of ecologically harmful Se and Ni contents in wastewater, respectively. We suggest that regulatory thresholds based on these bioassays should be set at TU = 1 for all the species or at TU = 1 for Aliivibrio and Ulva and TU = 2 for Daphnia and Lemna, if the number of companies whose wastewater discharge exceeds the allowable TU levels is <1 % or 5 % of the total number of industries, respectively. Taken together, these findings could help in establishing a rapid, ecologically relevant wastewater quality assessment system that would be useful for developing strategies to protect aquatic ecosystems.

Influence of graphene oxide on the toxicity of polystyrene nanoplastics to the marine microalgae Picochlorum sp

Graphene oxide (GO) features distinctive physical and chemical characteristics; therefore, it has been intensively investigated in environmental remediation as a promising material for clean-up of soil contamination and water purification and used as immobilization material. Plastic is a widespread pollutant, and its breakdown products such as nanoplastics (NPs) should be evaluated for potential harmful effects. This study is aimed to evaluate the influence of GO on the toxicity of polystyrene (PS) NPs to the marine microalgae Picochlorum sp. over a period of 4 weeks. The capability of GO to reduce the toxic effects of PS NPs was assessed through investigating exposure sequence of GO in the presence of 20 nm diameter-sized polystyrene NPs. This was accomplished through five test groups: microalgae pre-exposed to GO prior to incubation with PS NPs, microalgae post-exposed to GO after incubation with PS NPs, microalgae simultaneously exposed to GO and PS NPs, and individual exposure of microalgae to either GO or PS NPs. Cytotoxicity assay results demonstrated that microalgae pre-exposed to GO prior to incubation with PS NPs showed an increased viability and chlorophyll a content. The pre-exposure to GO has reduced the growth inhibition rate (IR) from 50%, for microalgae simultaneously exposed to GO and PS NPs, to 26%, for microalgae pre-exposed to GO. Moreover, the lowest level of reactive oxygen species (ROS) was recorded for microalgae exposed to GO only and microalgae pre-exposed to GO. Fourier-transform infrared (FTIR) analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) observations revealed some morphological changes of both algae and their extracellular polymeric substances (EPS) upon GO and PS NPs exposure combinations. The sequence of GO exposure to aquatic microorganisms might affect the level of harm caused by the PS NPs. Therefore, application of GO as part of an immobilization material and in the removal of pollutants from water should be carefully investigated using different pollutants and aquatic organisms.

Structural study and metal speciation assessments of waste PCBs and environmental implications: Outlooks for choosing efficient recycling routes

Environmental protection from risks and disposal management of discarded mobile phone printed circuit boards (MPhPCBs) is a global issue. Although recycling is proposed as a solution, it is challenging to choose a sustainable method due to the insufficient recognition from extreme structural heterogeneity of these wastes based on their types. To this end, a thorough study on the structural characterization of PCBs using different analyses and metal speciation by sequential extraction procedure were performed. Understanding these information is an essential step in order to choose efficient methods to maximize selective recycling of metals and minimize environmental implications. PCBs were found to be potent metallic reservoirs after all metal content of PCBs were precisely measured. The structural analysis results of the sample included identification of different phases, functional groups, 45.1 % of the crystalline and 54.9 % of amorphous, the mesoporous nature (pore diameter mean ∼ 7.24 nm), hydrophobic property (contact angle ∼93.4°), the positive ζ-potential of particles at pH < (isoelectric point ∼5.4) and vice versa, and the particle size that were not oversized. The metal speciation outcome indicated over 80 % of the total content of elements such as Si, Sn, Ag, Au, Sr, Al, Cr, Nd, Ca, Ba, and P was in a solid crystal structure/residual fraction, which were hard recycled. The assessment of contamination levels of waste indicated the considerable contamination for the environment at global contamination factor ∼27.7, the moderate ecological risk at potential ecological risk assessment ∼82.9, and threats to public health. In addition, the metals of Pr, Mn, and Zn pose high risks because of their risk assessment code values of 42.7 %, 36.7 %, and 33.1 %, respectively. Leaching tests proved Waste Extraction Test was an aggressive method. ANC4 proposed high level of H⁺ consumption are required for metal leaching in future works.

Printing ink wastewater treatment using combined hydrodynamic cavitation and pH fixation

Printing ink wastewater (PIW) carries a heavy load of pollutants, the composition of which makes treatment difficult, especially when trying to minimize the pollution load. According to the latter, the present study aims to investigate PIW treatment with different various methods and to determine the maximum color, COD (chemical oxygen demand) and TSS (total suspended solids) removal. First, hydrodynamic cavitation (HC) was tested and the effect of hydrogen peroxide dosage (0-10 g L^-1), and pH (3, 5, 8, 10) was examined concerning the removal of PIW initial COD concentrations 4000 and 8000 mg L^-1. Removal was high (more than 81%) only at pH 5 in HC reactor. The second method involved treatment with separate pH fixation of the undiluted PIW (COD 17000 mg L^-1, actual pH 8 ± 0.2). This treatment, maximized removals, reaching reduction of the initial values more than 91%, at pH 5. Finally, PIW was treated with a combination of the above methods, leading to 93-97% removals for 8000 mg L^-1 PIW treatment and 97-99% for 17000 mg L^-1 PIW respectively. Process cost calculations showed that the latter method is an effective and affordable treatment method for PIW streams, while toxicity tests of the treated PIW showed substantial toxicity reduction.

Monosodium glutamate in a type 2 diabetes context: A large scoping review

This scoping review aimed to map and elaborate the heterogenous and inconclusive body of evidence relating monosodium glutamate (MSG) and type 2 diabetes (T2DM). For this reason, multiple health outcomes related to T2DM were included and a systematic search was conducted. Experimental and observational trials between 1995 and January 2021 were collected. The tests were highly heterogenous in their samples, doses, route of exposures, durations, diets and conclusions. There was a pattern of negative effects of MSG at oral doses ≥2,000 mg/kg of body weight, and by gavage or injection at any given dose. Evidence was lacking in many areas and most of the evidence relied on short term tests. Further research should focus on standardizing and justifying methodologies, conducting long term studies and toxicokinetic tests, and avoiding bias. Focusing on the gaps highlighted and investigating mechanisms of action of MSG is crucial. Evidence-based toxicology is encouraged.

Effects of Polyester Fibers and Car Tire Particles on Freshwater Invertebrates

Microplastic ingestion has been shown for various organisms, but knowledge of the potential adverse effects on freshwater invertebrates remains limited. We assessed the ingestion capacity and the associated effects of polyester fibers (26-5761 µm) and car tire particles (25-75 µm) on freshwater invertebrates under acute and chronic exposure conditions. A range of microplastic concentrations was tested on Daphnia magna, Hyalella azteca, Asellus aquaticus, and Lumbriculus variegatus using water only (up to 0.15 g/L) or spiked sediment (up to 2 g/kg dry wt), depending on the habitat of the species. Daphnia magna did not ingest any fibers, but low levels of fibers were ingested by all tested benthic invertebrate species. Car tire particle ingestion rose with increasing exposure concentration for all tested invertebrates and was highest in D. magna and L. variegatus. In most cases, no statistically significant effects on mobility, survival, or reproductive output were observed after acute and chronic exposure at the tested concentrations. However, fibers affected the reproduction and survival of D. magna (no-observed-effect concentration [NOEC]: 0.15 mg/L) due to entanglement and limited mobility under chronic conditions. Car tire particles affected the reproduction (NOEC: 1.5 mg/L) and survival (NOEC: 0.15 mg/L) of D. magna after chronic exposure at concentrations in the same order of magnitude as modeled river water concentrations, suggesting that refined exposure and effect studies should be performed with these microplastics. Our results confirm that microplastic ingestion by freshwater invertebrates depends on particle shape and size and that ingestion quantity depends on the exposure pathway and the feeding strategy of the test organism. Environ Toxicol Chem 2022;41:1555-1567. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

The influence of methodology on the comparison of cytotoxicity of total-etch and self-etch adhesive systems

OBJECTIVES

The present study aimed to compare the in vitro cytocompatibility of two etch-and-rinse (Adper Scothbond, Optibond) and two self-etch (Clearfill SE Bond and Single Bond Universal) dental adhesives through a dentin-barrier model with human pulp fibroblasts.

METHODS

Human fibroblasts were placed on a plastic device containing 500μm human dentin discs treated with each adhesive or without treatment (control). Other groups were directly exposed to media conditioned with adhesive samples according to ISO 10993-5:2009. After 24h exposure, cell viability was assessed by XTT, and released inflammatory mediators were detected with a multiparametric immunoassay.

RESULTS

The standardized test without barrier indicated both etch-and-rinse adhesives and self-etch as cytotoxic, promoting viabilities under 70% of the control group (p<0.05). The dentin-barrier model identified increased cell viability for self-etch adhesives, with Clearfill SE Bond identified as non-cytotoxic. The immunoassay evidenced high rates of cytokines by cells exposed to the conditioned media of Adper Scotchbond, Optibond S, and Single Bond Universal.

CONCLUSIONS

The use of a dentin-barrier in vitro model detected a better biocompatibility for self-etching adhesives and, in the case of Clearfill SE Bond, with a reversion from cytotoxic to biocompatible when compared to the indirect standardized test.

CLINICAL SIGNIFICANCE

The use of a dentin-barrier in vitro model was able to detect a better biocompatibility for self-etching adhesives when compared to the indirect standardized test and presents itself as a predictive in vitro method for assessing the cytotoxicity of dental restorative materials that may simulate the clinical condition more accurately.

Silver nanoparticles effect on Artemia salina and Allium cepa organisms: influence of test dilution solutions on toxicity and particles aggregation

The objective of this study was to evaluate the effects of AgNPs on Artemia salina and Allium cepa, evaluating the influence of the dilution solutions on the particle behavior. The AgNPs were synthesized by chemical reduction of AgNO₃ (3 and 5 mmol L^-1) with sodium borohydride and stabilized with PVA (polyvinyl alcohol) and CMC (sodium carboxymethyl cellulose). The toxicity of AgNPs was evaluated in Artemia salina (mortality) using Meyer's solution as a diluent and in Allium cepa (chromosomal aberrations) using reconstituted hard water. AgNPs showed characteristic molecular absorption bands. Particles with CMC presented hydrodynamic radius between 4 and 102 nm and with PVA between 7 and 46 nm. The studied dispersions were toxic to A. salina species. Meyer's solution, used as dilution water in the test, caused precipitation of Ag⁺ and also caused changes in CMC-stabilized AgNPs, changing the shape of the nanoparticles by depositing precipitates on their surface. These changes make the results of toxicity difficult to interpret. AgNPs stabilized with PVA remained unchanged. AgNPs affected cell division and caused the appearance of chromosomal aberrations on A. cepa. Higher numbers of chromosomal aberrations occurred in dispersions with smaller particle diameters (AgNPs3-PVA and AgNPs5-PVA, without dilution). In the studied conditions the dispersions were toxic to the tested organisms, the concentrations of precursors and the type of stabilizer used influenced the particle size and toxicity. In the test with A. cepa, the reconstituted hard water did not cause changes in the dispersions of AgNPs, whereas for A. salina the Meyer solution promoted aggregation of the particles and precipitation, in the dispersions stabilized with CMC, thus changing the samples.

Retentive efficacy, antimicrobial and cytotoxicity comparisons between different types of commercial and experimental denture adhesives with antifungal action

The effect of the addition of nystatin and an alternative antifungal derived from pyrazoles in different commercial denture adhesives on their retentive efficacy, cytotoxicity and antimicrobial activity against Candida albicans was evaluated. Commercial denture adhesives were prepared with the inclusion of nystatin and 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamide (pyrazole) in three concentrations: 23.78 %w/w, 3.02 %w/w, and 0.31 %w/w (0.015 g, 0.0015 g, and 0.00015 g, respectively). The retentive efficacy was tested observing the influence of the medium, type of commercial denture type and the test condition (dipping). The antifungal action through disk diffusion and direct contact tests at 1, 4, 8 and 12 h and cytotoxic activity was evaluated in mouse fibroblasts (NIH/3T3) by the MTT reduction colorimetric assay. The addition of pyrazole and nystatin in commercial denture adhesives did not affect retentive efficacy rates and enhanced antifungal actions against Candida albicans. Results show a possibility of using denture adhesives as a delivery system for commercial antifungals (Nystatin) or pyrazole, with the second concentration (1,560 µg-3.02 %w/w) as the most efficient.

Apis mellifera and Melipona scutellaris exhibit differential sensitivity to thiamethoxam

Apis mellifera is a pollinator insect model in pesticide risk assessment tests for bees. However, given the economic and ecological importance of stingless bees such as Melipona scutellaris in the Neotropical region, as well as the lack of studies on the effect of insecticides on these bees, toxicity tests for stingless bees should be carried out to understand whether insecticides affect both species of bees in the same manner. Thus, the present study quantified the differential sensitivity of the bees M. scutellaris and A. mellifera to the oral ingestion of the insecticide thiamethoxam by determining the mean lethal concentration (LC₅₀), mean lethal time (LT₅₀), and their effect on the insecticide target organ, the brain. The results showed that the stingless bee is more sensitive to the insecticide than A. mellifera, with a lower LC₅₀ of 0.0543 ng active ingredient (a.i.)/μL for the stingless bee compared to 0.227 ng a.i./μL for A. mellifera. When exposed to a sublethal concentration, morphological and ultrastructural analyses were performed and evidenced a significant increase in spaces between nerve cells of both species. Thus, A. mellifera is not the most appropriate or unique model to determine the toxicity of insecticides to stingless bees.

In Vivo and In Vitro Toxicity Testing of Cyanobacterial Toxins: A Mini-Review

Harmful cyanobacterial blooms are increasing and becoming a worldwide concern as many bloom-forming cyanobacterial species can produce toxic metabolites named cyanotoxins. These include microcystins, saxitoxins, anatoxins, nodularins, and cylindrospermopsins, which can adversely affect humans, animals, and the environment. Different methods to assess these classes of compounds in vitro and in vivo include biological, biochemical, molecular, and physicochemical techniques. Furthermore, toxic effects not attributable to known cyanotoxins can be observed when assessing bloom material. In order to determine exposures to cyanotoxins and to monitor compliance with drinking and bathing water guidelines, it is necessary to have reliable and effective methods for the analysis of these compounds. Many relatively simple low-cost methods can be employed to rapidly evaluate the potential hazard. The main objective of this mini-review is to describe the assessment of toxic cyanobacterial samples using in vitro and in vivo bioassays. Newly emerging cyanotoxins, the toxicity of analogs, or the interaction of cyanobacteria and cyanotoxins with other toxicants, among others, still requires bioassay assessment. This review focuses on some biological and biochemical assays (MTT assay, Immunohistochemistry, Micronucleus Assay, Artemia salina assay, Daphnia magna test, Radionuclide recovery, Neutral red cytotoxicity and Comet assay, Enzyme-Linked Immunosorbent Assay (ELISA), Annexin V-FITC assay and Protein Phosphatase Inhibition Assay (PPIA)) for the detection and measurement of cyanotoxins including microcystins, cylindrospermopsins, anatoxin-a, saxitoxins, and nodularins. Although most bioassay analyses often confirm the presence of cyanotoxins at low concentrations, such bioassays can be used to determine whether some strains or blooms of cyanobacteria may produce other, as yet unknown toxic metabolites. This review also aims to identify research needs and data gaps concerning the toxicity assessment of cyanobacteria.

Comprehensive characterization and environmental risk assessment of end-of-life automotive catalytic converters to arrange a sustainable roadmap for future recycling practices

Environmentally appropriate economic recycling of spent automotive catalytic converters (SACCs) is difficult due to their complexity. The prominent reason is the lack of knowledge and comprehensive characterization of SACCs. This study focused on the characterization of SACCs in terms of their structural, morphological, physiochemical, surface, and thermal properties. The accurate determination of metals content, including 4975 mg/kg platinum group metals, 42,119 mg/kg rare earth elements, and other base metals, showed a great potential wealth in SACCs. Besides, the sequential extraction method was applied for metals fractionation, which represents a unique harsh recycling approach needed due to the stable structure of SACCs, metals embedded in silicate phases, and the presence of barely soluble metal phosphates. This waste was also examined for environmental criteria and leaching tests, including Toxicity Characteristic Leaching Procedure, Waste Extraction Test, and Synthetic Precipitation Leaching Procedure. The findings declare that Waste Extraction Test was the most aggressive procedure to assess mobility. The contamination indexes, such as risk assessment code, contamination factor, and global contamination factor, were also investigated, which show SACCs must be regarded as hazardous waste. As an example, the global contamination factor of 11.87 depicts SACCs have a moderate contamination degree.

Basic information for the development of a toxicity assay in inactivated bacterial vaccines

This study dealt with the toxicity of inactivated bacteria intended for veterinary autogenous vaccines toward a suitable control assay. Two in vitro methods were used. The [3-(4, 5 -dimethylthiazol-2-yl) -2,5 -diphenyltetrazolium bromide] (MTT) test, based on the metabolic reaction of a tetrazolium salt in vital cells, was adopted on the basis of previous positive results. The Interleukin (IL)-1 beta release assay on monocyte-derived pig macrophages was carried out for comparative purposes, to evaluate the possible role of the inflammatory response. MTT and IL-1 beta responses showed a significant correlation (P < 0.05) at defined test dilutions of bacterial antigens, whereas no correlation was demonstrated using MTT responses normalized on bacterial cell concentration. Furthermore, the toxic effects shown in the MTT test were positively correlated to the extracellular protein content. On the whole, the above results could be a useful basis for the development of a toxicity assay on inactivated bacterial vaccines. Also, our data point at bacterial autolysis as a major component underlying toxicity.

The Impact of Metal-Rich Sediments Derived from Mining on Freshwater Stream Life

Metal-rich sediments have the potential to impair life in freshwater streams and rivers and, thereby, to inhibit recovery of ecological conditions after any remediation of mine water discharges. Sediments remain metal-rich over long time periods and have long-term potential ecotoxicological interactions with local biota, unless the sediments themselves are physically removed or replaced by less metal-rich sediment. Laboratory-derived environmental quality standards are difficult to apply to the field situation, as many complicating factors exist in the real world. Therefore, there is a strong case to consider other, field-relevant, measures of toxic effects as alternatives to laboratory-derived standards and to seek better biological tools to detect, diagnose and ideally predict community-level ecotoxicological impairment. Hence, this review concentrated on field measures of toxic effects of metal-rich sediment in freshwater streams, with less emphasis on laboratory-based toxicity testing approaches. To this end, this review provides an overview of the impact of metal-rich sediments on freshwater stream life, focusing on biological impacts linked to metal contamination.

On how environmental and experimental conditions affect the results of aquatic nanotoxicology on brine shrimp (Artemia salina): A case of silver nanoparticles toxicity

The genus Artemia sp. has been accepted as a reliable model organism for aquatic toxicity and nanotoxicity experiments, as far as the ISO TS 20787 has recently been published to standardize nanotoxicity test with this organism. Experimental and environmental conditions may affect the toxicity of nanomaterials on aquatic organisms including Artemia sp. nauplii. In this study, acute toxicity effects of silver nanoparticles (AgNPs) on the nauplii of Artemia salina was investigated under various conditions (e.g. different lights, salinities, temperatures, volume and agitation of exposure media and instar stages of nauplii). The EC values were calculated using Probit program and all data were analyzed statistically by SPSS software. At all test conditions, the immobilization rate of Artemia nauplii increased in a concentration-dependent manner (P < 0.05). The sensitivity of instar stage II to different concentrations of AgNPs was significantly higher than instar I (P < 0.05). The toxicity effect of AgNPs was affected by alteration of environmental conditions, so that the effective concentration (EC) values for instar I of A. salina decreased with increasing water temperature, decreasing water salinity and in continuous darkness condition. The EC₅₀ value of AgNPs was significantly lower in 100 mL beakers (21.35 ± 5.67 mg L^-1) than 10 mL well plates (42.44 ± 11.30 mg L^-1). Agitation of exposure media did not affect the toxicity of AgNPs. The results indicated that the experimental and environmental conditions influence on the toxicity of AgNPs in the nauplii of A. salina.

A comparative study of 3 alternative avian toxicity testing methods: Effects on hepatic gene expression in the chicken embryo

There is growing interest in developing alternative methods to screen and prioritize chemical hazards, although few studies have compared responses across different methods. The objective of the present study was to compare 3 alternative liver methods derived from white Leghorn chicken (Gallus gallus domesticus): primary hepatocyte culture, liver slices, and liver from in ovo injected embryos. We examined hepatic gene expression changes after exposure to 3 chemicals (17β-trenbolone [17βT], 17β-estradiol [E2], and 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]) using a custom quantitative polymerase chain reaction (qPCR) array with 7 genes (vitellogenin [VTG], apolipoprotein [Apo], cytochrome P450 1A4 [CYP1A4], liver basic fatty acid binding protein [LBFABP], 3β hydroxysteroid dehydrogenase [HSD3β1], stearoyl coenzyme A desaturase [SCD], and estrogen sulfotransferase [SULT1E1]). Gene expression across the 3 methods was examined using hierarchical clustering. Up-regulation of CYP1A4 in response to TCDD was consistent across all methods, and the magnitude was higher in hepatocytes (>150-fold) compared with slices (>31-fold) and in ovo liver (>27-fold). In hepatocytes, SCD and VTG up-regulation in response to 17βT and E2 was >4-fold and 16-fold, respectively. The rank order of cases with significant changes in gene expression among the 3 methods was: hepatocytes (22) > in ovo liver (11) > liver slices (6). Hierarchical clustering grouped liver slices and in ovo liver as more similar, whereas hepatocytes were grouped separately from in ovo liver. More introspective comparisons are needed to understand how and why alternative methods differ and to aid in their integration into toxicity testing. Environ Toxicol Chem 2019;38:2546-2555. © 2019 SETAC.

Ecotoxicity of nano-metal oxides: A case study on daphnia magna

In Europe REACH framework directive imposes data acquisition concerning toxicity on acquatic species before the commercialization of chemicals to assess environmental risks. According to official methods, exposure tests are performed under in vitro and standardized conditions: OECD's guideline rules external variables such as water type, feeding conditions, and exposure time. As consequence, such obtained results could be different from effects observed in natural environments. This study collects effects within 24-96 h of exposure to nano metal-oxides (ZnO, TiO₂) on D. magna obtained by the exposure under standard OECD conditions comparing them with results obtained by the exposure under more similar conditions to natural environment (i.e. mixture, feeding). High doses exposure determines gas-bubble disease. Animals exposed to LC10 actively ingest nanoparticles under both fasting and feeding conditions. Furthermore, body burial by a coat of nanoparticles thicker in mixtures than in single dispersions was recorded. Furthermore, results show that: (i) effects increase over time; (ii) n-ZnO results less effective than n-TiO₂ in both single dispersion, and mixture; (iii) the presence of surfactant increases toxicity of nanoparticles; (iv) immobilization is a more sensitive endpoint than mortality; (v) feeding increases test sensitiveness improving differences among treated and controls till 96 h and allowing longer exposure times than standard OECD test. As general remark, this study provides evidence that in vitro ecotoxicological results obtained under standardized OECD conditions could be significant different to animals' responses under natural (feeding and mixtures) exposure conditions.

Strength of methods assessment for aquatic primary producer toxicity data: A critical review of atrazine studies from the peer-reviewed literature

Improving the quality of pesticide toxicity studies is a shared goal in ecotoxicology and a priority for risk assessors. Using the herbicide atrazine and testing on primary producers as a case study, we developed and applied a transparent scoring system for assessing the quality of peer-reviewed studies. The exercise also highlights where data gaps exist for planning future work. We determined that, while a large number of studies (147) present experimental data fitting basic inclusion criteria, only a small proportion provide sufficient information on the test substance, test organism, and test results to be considered of sufficient quality (i.e., a minimum score of >8 out of 16, meaning no critical study weaknesses identified) that would allow recommendation for their use in decision-making. Optimal studies for use in first tier risk assessment were further identified for each taxonomic group as the highest-scoring study scoring >8, that also used the technical grade active ingredient, reported an EC50 for a population-level endpoint (e.g. cell density, dry weight), and an exposure period in line with standard tests (≤96-h for algae, ≤14-d for macrophytes). Ultimately, 22 freshwater studies (four periphyton, ten macrophytes, and eight phytoplankton) achieved scores >8. Only one study with marine phytoplankton scored >8, and no studies met the risk assessment inclusion criteria for marine/estuarine periphyton or macrophytes. This indicates a potential research need with respect to toxicity data for salt-water species. Finally, registrant studies were evaluated, and in many cases, were the most appropriate for risk assessment, with the greatest scores observed for their respective species relative to those reported in the peer-reviewed literature. This exercise highlights the importance of defining and identifying well-performed toxicity tests, illuminating knowledge gaps, and reporting high quality data in support of the risk assessment process outside of the standard regulatory framework.

Leigongteng (Radix et Rhizoma Tripterygii) via compatibility with Jinqiancao (Herba Lysimachiae): its toxicity-reduced efficacy in H22-bearing mice

OBJECTIVE

To observe toxicity-reduced effects of Leigongteng (Radix et Rhizoma Tripterygii) (LGT) via compatibility with Jinqiancao (Herba Lysimachiae) (JQC) in H22-bearing mice and investigate the possible underlying mechanism, and further explore whether JQC can enhance LGT-evoked anti-tumor effect.

METHODS

H22-bearing mice were orally administered with LGT alone and its compatibility with JQC, and tumors, serum, livers and kidneys were collected to evaluate the toxicity-reduced efficacy and the possible mechanism.

RESULTS

LGT evoked significantly elevated biochemical indicators including serum alanine / aspartate transaminase (ALT/AST), creatinine (Cr) and urea nitrogen (BUN) as well as pathological damage in mice, which were all obviously reversed by JQC via compatibility at the ratios from 4/1 to 1/4. Further analysis indicated that pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α), and malondialdehyde (MDA) levels significantly decreased, while anti-inflammatory cytokine interleukin (IL)-10, and glutathione (GSH), GSH-s transferase (GST), GSH peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) levels all increased in livers and kidneys of mice. Besides, after compatibility with JQC at the ratios of 4/1, 2/1, 1/1, 1/2 and 1/4, LGT-decreased tumor weight was further decreased by 48.4%, 57.3%, 54.0%, 49.3% and 52.9%, respectively (all P < 0.01).

CONCLUSION

JQC could reduce LGT-induced hepatotoxicity and nephrotoxicity, and enhance the antitumor efficacy via compatibility with JQC, and the toxicity-reduced mechanism could involve inhibiting hepatic and kidney oxidative stress and inflammation.

Toxicity assessment of arsenic on common carp (Cyprinus carpio) and development of natural sorbents to reduce the bioconcentration by RSM methodology

The objective of the present study was firstly acute toxicity bioassay of arsenic on common carp (Cyprinus carpio) and then the development of natural sorbent beds (clinoptilolite and pumice) to reduce bioconcentration of arsenic in muscle tissue were considered in comparative evaluation. In this regard, the acute toxicity of arsenic on juvenile fish was assessed according to the OECD guideline (No. 203). Moreover, the efficacy of clinoptilolite and pumice as natural sorbents was assessed to reduce bioconcentration of arsenic in the fish muscle tissue during a 21 day by response surface methodology (RSM) under central composite design (CCD). The most important point of this study was to evaluate the interactions between independent variables (clinoptilolite and pumice as sorbents and arsenic as pollutant) and arsenic bioconcentration in fish muscle tissue as a dependent variable (response). In these regards, a total of 24 sets of experiments (12 sets for clinoptilolite and pumice separately) were designed by the software to achieve the best adsorption conditions. According to the arsenic toxicity test, results as estimated by Probit method, the 96 h LC₅₀ was 9.48 ± 1.01 mg/L. Analysis of variance (ANOVA) which was applied to modeling and optimization of response revealed that the predicted values were in relatively good agreement with the experimental data. Additionally, the obtained value for model desirability by clinoptilolite and pumice were 0.932 and 0.958, respectively. Overall, the obtained results indicate that both adsorbents reduced the bioconcentration of As (V) in the muscle tissue of common carp, but clinoptilolite was more effective.

Treatment of printing ink wastewater using electrocoagulation

The present study investigates the treatment of real printing ink wastewater by using the electrocoagulation (EC) process. Effects of initial chemical oxygen demand (COD) concentrations, electrode materials and current densities were examined to determine the maximum COD and color removal from the wastewater. In parallel, raw and treated printing ink wastewater toxic potential was further estimated via the application of toxicity tests using the freshwater crustacean Thamnocephalus platyurus for assessing EC process efficiency. According to the results, it was observed that the EC is efficient under most of the operating conditions used, as COD and color removal ranged between 72.03 to 85.81% and 98.7-100%, respectively. The total cost of the EC process, considering the treatment time, applied current, applied voltage and the total anode electrode mass consumption was also estimated. The Fe electrode proved to be of lower cost than the Al electrode, however the use of Al electrode produced better decolorization results in the solutions. Moreover, toxicity tests currently performed with the use of larvae of the fairy shrimp Thamnocephalus platyurus revealed a substantial decrease in the toxic potential of printing ink wastewater, thus indicating the efficiency of the proposed EC process.

[Content characteristics and cytotoxicity detection of silver ion products]

Objective: To analyze the silver content, homogeneity, and cytotoxicity of silver-containing products. Methods: (1) Five kinds of silver-containing products A, B, C, D, and E were purchased from the market, and products A, B, C, and D are liquid or gel form while product E was dressing form. The silver content of each product and the homogeneity of product E were determined by flame method. The sample number was 3. (2) Human hepatocellular carcinoma cell line (HepG2) was selected as the evaluation model. Four silver-containing products A, B, C, and D were diluted with high-glucose dulbecco's modified eagle medium (DMEM) at multiple ratios of 1∶100, 1∶200, 1∶400, and 1∶800, and then they were used for cell culture. Cells cultured with high-glucose DMEM and high-glucose DMEM containing 20 μg/mL silver nitrate were used as blank control and positive control, respectively. The cell viability was determined by methyl thiazolyl tetrazolium assay, and each sample number was 5. (3) Four mass concentrations of 0.031 3, 0.062 5, 0.125 0, and 0.250 0 μg/mL were prepared from silver-containing product A, and then they were used to culture HepG2 cell. Cells cultured with high-glucose DMEM containing fetal calf serum and 294 μg/mL potassium dichromate were used as positive control, while those containing fetal calf serum were used as blank control. Hoechst 33258 staining method was used to detect apoptosis rate of cells. The tail moment, tail length, and the percentage of DNA in the tail of cells were observed by comet assay to evaluate DNA damage. The sample numbers were all 3. Data were processed with one-way analysis of variance and least significant difference-t test. Results: The silver content of products A, B, C, and D was (256.5±1.5) μg/mL, (271.5±1.3) μg/mL, (652.4±2.6) μg/g , (330.0±2.1) μg/g, which was in accordance with labelled amount. The silver content of product E was (0.158±0.013) mg/g, and the silver content of each piece of product E was (0.125±0.017) mg/g, showing good uniformity of product E. (2) Compared with the rate of blank control, the cell survival rates of product A at the dilution ratio of 1∶100, product B at the dilution ratio of 1∶100, and product C at the dilution ratio of 1∶100 and 1∶200 were significantly reduced (t=35.506, 8.914, 37.594, 30.693, P<0.01). Compared with the rate of positive control, the cell survival rates of product A at the dilution ratio of 1∶200, 1∶400, and 1∶800, product C at the dilution ratio of 1∶400 and 1∶800, products B and D at each dilution ratio were increased significantly (t=27.537, 18.262, 18.709, 26.333, 41.762, 15.776, 19.759, 20.443, 15.715, 26.792, 24.963, 31.803, 30.537, P<0.01). (3) The apoptosis rates of cells treated by 0.250 0 μg/mL product A and positive control were (6.1±0.4)% and (62.2±3.9)% respectively, which were significantly higher than the apoptosis rate of blank control [(3.3±0.7)%, t=13.327, 30.475, P<0.05]. The apoptosis rates of cells treated by 0.031 3, 0.062 5, 0.125 0 μg/mL product A were (2.9±0.4)%, (3.1±0.4)%, and (4.2±0.9)% respectively, which were close to the apoptosis rate of blank control (t=1.181, 0.133, 1.097, P>0.05). (4) The tail moment, tail length, and tail DNA percentage of cells cultured with 0.125 0 and 0.250 0 μg/mL product A were significantly higher than those cultured with blank control (t=29.026, 51.194, 21.851, 36.138, 24.721, 50.455, P<0.05 or P<0.01). However, the tail moment, tail length, and tail DNA percentage of cells cultured with 0.031 3 and 0.062 5 μg/mL product A were close to those cultured with blank control (t=5.878, 3.429, 2.779, 1.960, 1.328, 7.763, P>0.05). Conclusions: The silver content of silver-containing products meets the requirements of the labeling. The concentration of product C is higher than that of other products, leading to a greater possibility of decreasing the survival rate of HepG2 cells. It is suggested that the products A and B should be taken as reference in the concentration setting of silver ion products. The product solution with higher concentration may have higher risk of damage to cell DNA. Therefore, it is not recommended to upregulate silver content of relevant products blindly in order to achieve better antibacterial effect.

Twelve-week study of moxa smoke: occupational exposure in female rats

OBJECTIVE

To assess the toxicity of moxa smoke in rats.

METHODS

Forty-eight female Wister rats were randomly divided into 4 groups (n = 12/group) to simulate moxa smoke exposure in Chinese medicine clinics (CMCs): the control group, and three moxa-smoke exposed groups of PM10 mass concentrations 3-5, 7-9 and 27-30 mg/m3 , respectively. These concentrations were 1 × , 2-3 × , and 7-9 × fold the concentrations found in CMCs. Exposures continued for 12 weeks (200 min/d, 5 d/week).

RESULTS

No deaths were noted. After the exposure, the body weights, ratios of organ weight to body weight, urinary parameters, hematological parameters, clinical chemistry parameters and microscopic examinations revealed no obvious toxicity.

CONCLUSION

Moxa smoke did not induce toxic effects in female rats in the study. These findings provide new evidence to the toxicity of moxa smoke.

Adaptation of a skin sensitization assay to a chemically defined culture

There are currently three in vitro methods adopted by the Organization for the Economic Co-operation and Development for testing chemicals based on the third key event of the skin sensitization adverse outcome pathway, the activation of dendritic cells. All of them use culture medium supplemented with fetal bovine serum (FBS), which brings technical disadvantages and animal welfare concerns. The objective of this study was to analyze the possibility of eliminating the use of FBS in the human Cell Line Activation Test (h-CLAT). After successful implementation of the h-CLAT using THP-1 cells cultured in FBS-containing medium, several attempts to adapt THP-1 cells to four different serum-free media were made. The best results were obtained with gradual adaptation to RPMI-1640 medium with HL-1™ Supplement and to X-VIVO™ 10. Adapted cells were cryopreserved and submitted to the reactivity check. After being approved, they were used in dose finding and proficiency assays. Despite minor adjustments in the original protocol, it was possible to correctly predict the sensitizing potential of the ten proficiency substances using THP-1 cells adapted to X-VIVO™ 10, which indicates that it is possible to eliminate the use of FBS in the h-CLAT, using a chemically defined medium.

What is the best endpoint for assessing environmental risk associated with acidification caused by CO2 enrichment using mussels?

Carbon capture and storage is a technology that has been widely determined to be one of the best choices for the short-term reduction of atmospheric CO₂ emissions. The aim of this study was to analyze the effects of CO₂ enrichment in the ocean on the mussel species Mytilus galloprovincialis using three different endpoints: mortality, embryo-larval development, and neutral red retention time assays (NRRT). Acute effects were found to be associated with a pH values of 6.0 while citotoxity effects and embryo-larval development were associated with a pH value of 7.0. The NRRT assay and embryo-larval development can be recommended as good endpoints for assessing the environmental risk associated with acidification by CO₂ enrichment because they provide sensitive responses on the effects of changes in seawater pH on mussels in a short period of time. Moreover, this study may support policymakers in finding appropriate solutions for the conservation of marine ecosystems.

Repeated exposure to moxa-burning smoke: its acute and chronic toxicities in rats

OBJECTIVE

To assess toxicities of the air in Chinese medicine clinics polluted by moxa-burning smoke due to moxibustion-derived burning products (MBP).

METHODS

Both acute and chronic toxicity studies were conducted. For the acute toxicity study, five groups of Wistar rats (n = 16/group, male: female = 1∶1) were exposed to five different concentrations (95%, 90%, 85%, 80% and 75%, respectively) of MBP for 2 h. For the chronic toxicity study, another three groups of male rats (n = 21/group) were exposed to MBP in three concentrations (10%, 40% and 70%, respectively) and one control group exposed to clean air 20 min/d for 144 d. Routine examinations were performed and analyzed by analysis of variance and dose-response relationship.

RESULTS

In the acute toxicity study, the number of dead rats in the 95%, 90%, 85%, 80% and 75% groups were 16, 13, 7, 6 and 3, respectively, with LD50 of 86.274% after or during the 2 h exposure. In the chronic toxicity study, MBP exposure induced a decline in activity of the rats. Rats in the 10% group showed no signs of toxicity, while those in the 40% MBP group showed toxicity effects on the body weights (P < 0.05) and lung. Rats in the 70% MBP group also presented with reversible damage in the blood coagulation system (P < 0.05).

CONCLUSION

Exposure to 10% MBP, which is equivalent to 27.45 mg/m3, was under the critical threshold for male rats' safety. Exposure to MBP above that limit induced lung damage. MBP in clinics need to be reduced to a safe level with enhanced ventilation.

Toxicity of naproxen sodium and its mixture with tramadol hydrochloride on fish early life stages

Pharmaceuticals occur in water bodies as a consequence of their incomplete removal during waste water treatment processes. The occurence of pharmaceuticals in surface waters as well as their possible impact on aquatic vertebrates have received considerable attention in recent years. However, there is still a lack of informations on the chronic effects of widely used drugs as well as their possible mixture toxicity on non-target aquatic vertebrates as well as their possible mixture toxicity. The aim of this study was to assess the effects of naproxen sodium on early life stages of fish and evaluate its mixture toxicity with tramadol hydrochloride, which was assessed in our earlier study as a single substance. Two embryo-larval toxicity tests with common carp (Cyprinus carpio) were performed according to the OECD guideline 210 (Fish, Early-life Stage Toxicity Test) in order to assess the subchronic toxicity of naproxen sodium and tramadol hydrochlorid-naproxen sodium mixture at the concentrations of 10; 50; 100 and 200 μg/L. These experiments were conducted for 32 days. The subchronic exposure to naproxen sodium and naproxen sodium and tramadol hydrochloride mixture had a strong effect on the early life stages of common carp. Hatching, developmental rate, morphology, histopathology and, in the case of the naproxen sodium and tramadol hydrochloride mixture, mortality were influenced. The bioindicators of oxidative stress were also influenced. The LOEC was determined at 10 μg/L for both naproxen sodium and naproxen sodium and tramadol hydrochloride mixture.

Assessing the influence of ocean acidification to marine amphipods: A comparative study

CO₂ increases in the ocean may occur both by the capacity of CO₂ exchanges with its dissolved form between atmosphere and surface seawater as well by CO₂ leaks during the carbon capture and storage (CCS) process. The decrease in seawater pH may result in a reduction in the concentration of both hydroxide and carbonate (OH^- and CO₃^2-). The main aim of this work is to conduct an ecotoxicology comparative survey using two amphipod species from Europe and Brazil exposed to different acidification (CO₂) scenarios. For it, an integrative approach based on the weight of evidence was used for comparative proposes to identify the effects on the amphipods association with the acidification and with the related mobility of metals. The results demonstrate that the Ampelisca brevicornis species is more sensitive to pH reductions than the Hyale youngi species. Furthermore, this study has demonstrated that the CO₂ enrichment in aquatic ecosystems would cause changes on the mobility of certain metals (Zn, Cu and As). The results of Principal Component Analysis (PCA) showed that the dissolved Zn in overlying water was strongly correlated with the decrease in the pH and was associated with increased toxicity of the sediment to the exposed organisms, mainly for the A. brevicornis species from Spain. Nevertheless, similar results were found in relation to the mortality of amphipods in low pH values for all sediment tested. Concluding, it is highlighted the importance of comparative studies in different types of environment and improve the understood of the risks associated with the ocean acidification.

Comparative evaluation of sea-urchin larval stage sensitivity to ocean acidification

Changes in the marine carbonate system may affect various calcifying organisms. This study is aimed to compare the sensitivity of embryo-larval development of two species of sea urchins (Paracentrutos lividus and Lytechinus variegatus) collected and exposed to samples from different coastal zone (Spain and Brazil) to ocean acidification. The results showed that the larval stages are very sensitive to small changes in the seawater's pH. The larvae from P. lividus species showed to be more sensitive to acidified elutriate sediments than larvae from L. variegatus sea urchin. Furthermore, this study has demonstrated that the CO₂ enrichment in aquatic ecosystems cause changes on the mobility of the metals: Zn, Cu, Fe, Al and As, which was presented different behavior among them. Although an increase on the mobility of metals was found, the results using the principal component analysis showed that the pH reduction show the highest correlations with the toxicity and is the main cause of embryo-larval development inhibition. In this comparative study it is demonstrated that both species are able to assess potential effects of the ocean acidification related to CO₂ enrichment by both near future scenarios and the risk associated with CO₂ leakages in the Carbon Capture and Storage (CCS) process, and the importance of comparative studies in different zones to improve the understanding of the impacts caused by ocean acidification.

Anti-inflammatory and toxicological evaluation of Moussonia deppeana (Schldl. & Cham) Hanst and Verbascoside as a main active metabolite

ETHNOPHARMACOLOGICAL RELEVANCE

Moussonia deppeana, known as Tlachichinole, is a Mexican medicinal plant used for treatment of inflammatory diseases, influenza, diarrhea, gastrointestinal disorders and arthritis.

AIM OF THE STUDY

In this paper the antioxidant and anti-inflammatory activities as well as the acute and sub-acute toxicological effects were evaluated for the ethanolic extract from aerial parts of M. deppeana, also its phytochemical analysis is described.

MATERIALS AND METHODS

Phytochemical analysis and compound isolation were performed with thin layer chromatography. The chemical identification of the main compound was performed by (1)H NMR (COSY, NOESY, HSQC and HMBC) spectra. In vitro antioxidant capacity and total phenolic content for the ethanolic extract and its primary fractions was determined by DPPH and Folin-Ciocalteu reagent. Acute and subacute toxicity tests were evaluated on Balb/C mice. Finally acute anti-inflammatory evaluation was tested for a local (TPA) and systemic (carrageenan) murine model.

RESULTS

The main compound isolated from the ethanolic extract of M. deppeana was Verbascoside, which was isolated from F3 and was identified by (1)H NMR and COSY data. Furthermore oleanolic and ursolic acids were isolated from primary fractions F1 and F2. Ethanolic extract showed IC50 = 6.71mg/mL for DPPH test and 664.12µg QE/mL for the total phenolic content. The LD50 value was >2g/kg by i.g. route in male and female mice. Sub-acute administration (28 days) of the ethanolic extract (1g/kg) did not cause lethality or alter any hematological and biochemical parameters, in addition, histological analysis of the major organs exhibited no structural changes. Anti-inflammatory activity of the ethanolic extract showed an ED50 = 1.5mg/ear and 450mg/kg for TPA and carrageenan test, respectively. Primary fractions generated moderate local and systemic anti-inflammatory activity.

CONCLUSION

The ethanolic extract from the aerial parts of M. deppeana did not cause any lethality or adverse effect in either of the acute and sub-acute toxicity tests. This exhibited an important local and systemic anti-inflammatory activity and also moderate antioxidant capacity. Moreover, the primary fraction F2 was more active for the TPA model while the primary fraction F3 was most active in the carrageenan model in vivo. The main compound isolated from F3 was verbascoside; on the other hand also ursolic and oleanolic acids were isolated from F1 and F2.

May arsenic pollution contribute to limiting Artemia franciscana invasion in southern Spain?

Limited information exists regarding the complex interactions between biological invasions, pollution, and climate change. Most studies indicate that pollution tends to favor invasive species. Here, we provide evidence that arsenic (As) pollution may have a role in limiting the invasion of the exotic brine shrimp Artemia franciscana. We tested As toxicity in natural populations of Artemia parthenogenetica (a native taxon) and A. franciscana from localities in southern Spain with differing degrees of As contamination. Tests were conducted both under current mean temperature conditions (25 °C), and as per a future climate scenario (i.e., an increase in mean temperature of 4 °C). Acute toxicity was estimated on the basis of the median lethal concentration (at 24 h), and chronic toxicity was evaluated by measuring Artemia survival and growth under sublethal exposures (after 26 days). At 25 °C, native A. parthenogenetica from the highly polluted Odiel and Tinto estuary was much more resistant to acute As stress (LC₅₀-24 h, 24.67 mg L⁻¹) than A. franciscana (15.78 mg L⁻¹) and A. parthenogenetica from unpolluted sites (12.04 mg L⁻¹)–suggesting that local adaptation to polluted conditions may occur. At 29 °C, resistance of A. parthenogenetica from Odiel decreased significantly, and there were no statistical differences in sensitivity between the three species/populations, suggesting that climate change may enhance the probability of invasion. Resistance increased with developmental stage from nauplii to adults, and was extremely high in cysts which still hatched at As concentrations of up to 6400 mg L⁻¹. Under sublethal chronic exposure A. franciscana performed better (survival and growth) than A. parthenogenetica, and both species experienced a faster growth when exposed to As, compared with unexposed (control) individuals, probably due to the hormesis. We discuss the ecological implications of our results.

Lightsticks content toxicity: effects of the water soluble fraction on the oyster embryonic development

Lightsticks are artifacts used as attractors in a type of commercial fishery, known as surface longline gear. Despite the excessive use, the contamination risks of these devices have not yet been properly investigated. This research aimed to fill up this gap by determining the chemical composition and the toxicity of lightsticks recently activated, compared to those one year after activation and to the ones collected on the beaches. The analyzes were carried out by Gas Chromatography coupled with Mass Spectrometry (GC-MS). Additionally, the variations in composition and the toxicity of their sea Water Soluble Fractions (WSF) were evaluated based on the WSF-effects of Crassostrea rhizophorae embryonic development. The GC-MS analysis made possible the identification of nineteen substances in the water soluble fraction of the lightsticks, such as dibutyl phthalate (DBP) and dimethyl phthalate (DMP). The value of the WSF-effective concentration (EC50) was in an average of 0.35%. After one year of the lightsticks activation, the toxicity was even higher (0.65%). Furthermore, other substances, also present in the lightsticks-WSF caused persistent toxicity even more dangerous to the environment than DBP and DMP. This essay discusses their toxicity effects and possible environment damages.

The effect of copper and temperature on juveniles of the eurybathic brittle star Amphipholis squamata--exploring responses related to motility and the water vascular system

The limited availability of test organisms that represent tropical and deeper water environments is a significant concern when assessing the risk of contaminants in these environments. Amphipholis squamata (Delle Chiaje 1828) is a widely distributed brittle star with many phylogenetic clades reported from different latitudes, and it also occurs from the intertidal zone to a depth of ∼1300 m. In the present study, the effect of copper on four behavioural responses and mortality of A. squamata were quantified at four different temperatures including 25, 20, 15 and 10°C. At 25°C the four behavioural responses and mortality were relatively sensitive to copper, with 96 h EC50 values of 25 (confidence interval 18-44), 24 (7-26), 32 (24-41), 29 (9-41) μg L(-1) for the measured ability to turn from the oral surface up to oral surface down, curling behaviour, tube foot movement, and tube foot retraction respectively. The average 96-h LC50 value for copper at 25°C was 46 μg L(-1). Some endpoints investigated showed significant effects of reduced temperature compared to the optimal temperature. These effects were enhanced with increasing copper concentrations and significant differences in copper toxicity between temperature treatments were most notable when measuring the ability to turn from the oral surface up to oral surface down where the EC50 changed from 25 (18 to 44) to 6 (-18 to 14) μg L(-1) with a reduction of temperature from 25 to 15°C. The results showed that A. squamata is relatively sensitive to copper and that further investigation into the effects of other stressors on these endpoints is warranted.

Environmental assessment of dredged sediment in the major Latin American seaport (Santos, São Paulo-Brazil): an integrated approach

This work offers an environmental assessment of a dredged sediment disposal area in Santos bay, situated on the central coast of the São Paulo State, Brazil. Sediment quality was evaluated through physicochemical analysis and toxicity tests of sediments collected in the disposal site and adjacent area. The physicochemical characterization of the sediments involved grain size distribution, concentrations of polycyclic aromatic hydrocarbons (PAHs), chlorinated and aromatic hydrocarbons, polychlorinated biphenyls (PCBs), pesticides, phthalates, metals and nutrients. Acute and chronic toxicity tests were employed, using amphipods (Tiburonella viscana) and sea urchins (Lythechinus variegatus), respectively. Results revealed toxicity by all the methods applied here, suggesting that the area of disposal of dredged material is significantly altered with respect to sediment quality and probably capable of generating deleterious effects on the local biota. Aiming to elucidate the association between the distinct environmental variables and the biological effects measured in laboratory, Factor Analysis was performed. Results revealed that despite most contaminant concentrations were found below the limits established by Brazilian legislation, biological effects were related to metals (chronic toxicity) and organic compounds (acute toxicity). The application of multivariate analysis proved to be particularly useful to assess and interpret the results in an integrated way, particularly due to the large number of parameters analyzed in environmental assessments, and should be applied in future studies.

Chemical pollution and toxicity of water samples from stream receiving leachate from controlled municipal solid waste (MSW) landfill

The present study was aimed to determine the impact of municipal waste landfill on the pollution level of surface waters, and to investigate whether the choice and number of physical and chemical parameters monitored are sufficient for determining the actual risk related to bioavailability and mobility of contaminants. In 2007-2012, water samples were collected from the stream flowing through the site at two sampling locations, i.e. before the stream׳s entry to the landfill, and at the stream outlet from the landfill. The impact of leachate on the quality of stream water was observed in all samples. In 2007-2010, high values of TOC and conductivity in samples collected down the stream from the landfill were observed; the toxicity of these samples was much greater than that of samples collected up the stream from the landfill. In 2010-2012, a significant decrease of conductivity and TOC was observed, which may be related to the modernization of the landfill. Three tests were used to evaluate the toxicity of sampled water. As a novelty the application of Phytotoxkit F™ for determining water toxicity should be considered. Microtox(®) showed the lowest sensitivity of evaluating the toxicity of water samples, while Phytotoxkit F™ showed the highest. High mortality rates of Thamnocephalus platyurus in Thamnotoxkit F™ test can be caused by high conductivity, high concentration of TOC or the presence of compounds which are not accounted for in the water quality monitoring program.

Soil ecotoxicology: state of the art and future directions

Developments in soil ecotoxicology started with observations on pesticide effects on soil invertebrates in the 1960s. To support the risk assessment of chemicals, in the 1980s and 1990s development of toxicity tests was the main issue, including single species tests and also more realistic test systems like model ecosystems and field tests focusing on structural and functional endpoints. In the mean time, awareness grew about issues like bioavailability and routes of exposure, while biochemical endpoints (biomarkers) were proposed as sensitive and potential early-warning tools. In recent years, interactions between different chemicals (mixture toxicity) and between chemical and other stressors attracted scientific interest. With the development of molecular biology, omics tools are gaining increasing interest, while the ecological relevance of exposure and effects is translating into concepts like (chemical) stress ecology, ecological vulnerability and trait-based approaches. This contribution addresses historical developments and focuses on current issues in soil ecotoxicology. It is concluded that soil ecotoxicological risk assessment would benefit from extending the available battery of toxicity tests by including e.g. isopods, by paying more attention to exposure, bioavailability and toxicokinetics, and by developing more insight into the ecology of soil organisms to support better understanding of exposure and long-term consequences of chemical exposure at the individual, population and community level. Ecotoxicogenomics tools may also be helpful in this, but will require considerable further research before they can be applied in the practice of soil ecotoxicological risk assessment.

Determination of the mutagenicity potential of supermint herbal medicine by single cell gel electrophoresis in rat hepatocytes

PURPOSE

The increasing use of herbal drugs and their easy availability have necessitated the use of mutagenicity test to analyze their toxicity and safety. The aim of this study was to evaluate the genotoxicity of Supermint herbal medicine in DNA breakage of rat hepatocytes in comparison with sodium dichromate by single cell gel electrophoresis technique or comet assay.

METHODS

Hepatocytes were prepared from male wistar rats and were counted and kept in a bioreactor for 30 minutes. Then cells were exposed to the Supermint herbal medicine at doses of 125, 250 and 500 µl/ml. Buffer 4 (incubation buffer) and sodium dichromate were used as negative and positive control for one hour respectively. Then cell suspension with low melting point agarose were put on precoated slides and covered with agarose gel. Then lysing, electrophoresis, neutralization and staining were carried out. Finally the slides were analyzed with fluorescence microscope. The parameter under this analysis was the type of migration which was determined according to Kobayashi pattern.

RESULTS

With increased dose of Supermint herbal medicine the DNA damage was slightly increased (P<0001). Conlusion: In overall compared to the positive control significant differences is observed which convinced that the crude extract of Supermint in vitro did not have mutagenic effect. Conlusion: In overall compared to the positive control significant differences is observed which convinced that the crude extract of Supermint in vitro did not have mutagenic effect.