Toxics最新文献

Nowadays, synthetic polymer (plastic) particles are ubiquitous in the environment. It is known that for several decades microplastics (MPs) have been accumulating in the World Ocean, becoming available to a large variety of marine organisms. Particularly alarming is the accumulation of aging plastic particles, as the degradation processes of such particles increase their toxicity. The diverse display of negative properties of aging MPs and its effect on biota are still poorly understood. In this study, in vitro experiments modeling the interaction of pristine and UV-irradiated aging polypropylene (PP) fragments with hemocytes and mitochondria of bivalve mollusks Mytilus sp. were performed. The appearance of free radicals in the environment was recorded by spectral characteristics of indicator dyes-methylene blue (MB) and nitroblue tetrazolium (NBT). It was found that due to photooxidation, aging PP fragments sorbed more than threefold MB on their modified surface compared to pristine samples of this polymer. Using NBT, the formation of reactive oxygen species in seawater in the presence of pristine and photoactivated PP was recorded. It was also found that photodegraded PP fragments largely stimulated the development of lipid peroxidation processes in mitochondrial membranes and reduced the stability of hemocyte lysosome membranes compared to pristine PP fragments. In general, the results obtained concretize and supplement with experimental data the previously stated hypothesis of toxicity of aging MPs.

Since zinc oxide (ZnO) nanoparticles (NPs) have been widely applied, the nano community and the general public have paid great attention to the toxicity of ZnO NPs. We detected 20-nm ZnO NPs biotoxicity following nasal exposure utilizing the non-invasive and real-time magnetic resonance imaging (MRI) technique. MR images were scanned in the rat olfactory epithelium (OE) and olfactory bulb (OB) on a 4.7 T scanner following the treatment (as early as 1 day and up to 21 days after), and the histological changes were evaluated. The influence of the size of the ZnO NPs and chemical components was also investigated. Our study revealed that 20-nm ZnO NPs induced obvious structural disruption and inflammation in the OE and OB at the acute stage. The results suggest that the real-time and non-invasive advantages of MRI allow it to observe and assess, directly and dynamically, the potential toxicity of long-term exposure to ZnO NPs in the olfactory system. These findings indicate the size-dependent toxicity of ZnO NPs with respect to the olfactory bulb. Further study is needed to reveal the mechanism behind ZnO NPs' toxicity.

Toxicity mechanisms of per- and polyfluoroalkyl substances (PFASs), a chemical class present in diverse ecosystems, as well as many of their precursors, have been increasingly characterized in aquatic species. Perfluorooctanesulfonamide (PFOSA, C₈H₂F₁₇NO₂S) is a common precursor of perfluorooctane sulfonic acid (PFOS), a long-chain PFAS. Here, we assessed sub-lethal endpoints related to development, oxidative stress, transcript levels, and distance moved in zebrafish embryos and larvae following continuous exposure to PFOSA beginning at 6 h post-fertilization (hpf). PFOSA decreased survival in fish treated with 1 µg/L PFOSA; however, the effect was modest relative to the controls (difference of 10%). Exposure up to 10 µg/L PFOSA did not affect hatch rate, nor did it induce ROS in 7-day-old larvae fish. The activity of larval fish treated with 100 µg/L PFOSA was reduced relative to the solvent control. Transcripts related to oxidative stress response and apoptosis were measured and BCL2-associated X, apoptosis regulator (bax), cytochrome c, somatic (cycs), catalase (cat), superoxide dismutase 2 (sod2) were induced with high concentrations of PFOSA. Genes related to neurotoxicity were also measured and transcript levels of acetylcholinesterase (ache), elav-like RNA binding protein 3 (elavl3), growth-associated protein 43 (gap43), synapsin II (syn2a), and tubulin 3 (tubb3) were all increased in larval fish with higher PFOSA exposure. These data improve our understanding of the potential sub-lethal toxicity of PFOSA in fish species.

Hexavalent chromium (Cr[VI]) is a widespread environmental pollutant in air and water that is primarily attributed to industrial pollution. The current maximum contaminant levels (MCLs) for drinking water from the World Health Organization and the U.S. Environmental Protection Agency (0.05 and 0.1 mg/L, respectively) were set based on contact dermatitis and warrant further toxicological investigation. While Cr(VI) is neurotoxic and accumulates in the brain, most animal studies only report whole-brain Cr, leaving large knowledge gaps. Few studies consider differences between ages or sexes, and fewer consider essential metal dyshomeostasis. We sought to investigate where Cr accumulates in the brain, considering sex and age differences, following a 90-day drinking water exposure to current MCLs. Here, we report Cr levels in six brain regions of rats exposed to drinking water Cr(VI). We observed Cr only accumulated in the hippocampus, and only in older females. We further assessed changes to essential metals in the hippocampus, observing opposite effects across sexes and between young rats compared to older rats. In sum, our data indicate drinking water Cr(VI) selectively targeted the hippocampus, with geriatric females accumulating the most Cr, and induced significant essential metal dyshomeostasis even in tissues lacking evident Cr accumulation.

Developing efficient and sustainable pollution control technologies has become a research priority in the context of escalating global environmental pollution. Nano zero-valent iron (nZVI), with its high specific surface area and strong reducing power, demonstrates remarkable performance in pollutant removal. Still, its application is limited by issues such as oxidation, passivation, and particle aggregation. White rot fungi (WRF) possess a unique enzyme system that enables them to degrade a wide range of pollutants effectively, yet they face challenges such as long degradation cycles and low degradation efficiency. Despite the significant role of nZVI in pollutant remediation, most contaminated sites still rely on microbial remediation as a concurrent or ultimate treatment method to achieve remediation goals. The synergistic combination of nZVI and WRF can leverage their respective advantages, thereby enhancing pollution control efficiency. This paper reviews the mechanisms, advantages, and disadvantages of nZVI and WRF in pollution control, lists application examples, and discusses their synergistic application in pollution control, highlighting their potential in pollutant remediation and providing new insights for combined pollutant treatment. However, research on the combined use of nZVI and WRF for pollutant remediation is still relatively scarce, necessitating a deeper understanding of their synergistic potential and further exploration of their cooperative interactions.

Chemometric evaluation of potentially harmful volatile compound and toxic metal(loid) distribution patterns in fruit spirits relating to distinct fruit classes most commonly used in spirit production highlighted the potential of several volatiles as candidates for differentiation markers while dismissing toxic metal(loid)s. Pome fruit and grape pomace spirits were mostly characterized by a lower abundance of n-propanol, methanol, ethyl acetate and acetaldehyde, while stone fruit spirits contained lower amounts of isoamyl alcohol and isobutanol. Chemometric analysis of the fruit spirit composition of aromatics identified additional potential markers characteristic for certain fruits-benzoic acid ethyl ester, benzyl alcohol, benzaldehyde, butanoic acid 3-methyl-ethyl ester, butanoic acid 2-methyl-ethyl ester and furfural. This study explored the variability in the risk potential of the investigated spirits, considering that some chemicals known to be detected in spirits are potent health hazards. Ethyl carbamate in combination with acetaldehyde showed a higher potential risk in stone fruit spirits, methanol in stone and pome fruit spirits and acetaldehyde in grape pomace spirits. It is of great interest to evaluate to what extent consumers' preference for spirits of distinct fruit types affects health risks. Consumers of stone fruit spirits are potentially at higher risk than those consuming pome fruit or grape pomace spirits.

Firefighter occupational exposures were categorized as a class 1 (known) carcinogen by the International Agency for Research on Cancer in 2022. As a result, firefighters have become heavily focused on identifying effective and easy to implement decontamination strategies to reduce their chemical exposures. Skin decontamination using wipes post-exposure is one decontamination strategy that every firefighter has available to them. However, firefighters have expressed concerns over the ingredients in the wipe solution increasing dermal absorption. The goal of this study was to determine if the ingredients in skin decontamination wipe solution had any enhancement effect on the dermal absorption of phenanthrene. To determine any enhancement effects, the additive solution of four skin decontamination wipe products was applied to porcine skin 15 min after chemical dosing. The absorption of phenanthrene was tested in vitro using a flow-through diffusion cell system over eight hours. The wipe solution effects on dermal absorption were determined by measuring multiple absorption characteristics including cumulative absorption (µg/cm²), absorption efficiency (% dose absorbed), lag time (minutes), flux (µg/cm²/h), diffusivity (cm²/h), and permeability (cm/h). No penetration enhancement effects were observed in any of the skin decontamination wipe solutions tested; rather, all wipe solutions decreased the absorption of phenanthrene. Slight differences in cumulative absorption among two pairings of skin decontamination wipe solutions, wipes 1 and 3 vs. wipes 2 and 4, were observed, indicating that some ingredients may impact dermal absorption. These findings show that firefighters should continue using skin decontamination wipes to reduce their dermal exposures to fireground contaminants with little concern of increasing the absorption of phenanthrene.

For many decades, natural and modified clay minerals have been used as adsorbents to clean up aquatic and soil ecosystems contaminated with organic and inorganic pollutants. In this study, organoclays based on bentonite and various amphoteric and nonionic surfactants were synthesized and tested as effective sorbents for lead ions. The maximum values of R were obtained when describing the sorption processes using the Langmuir model, which ranged from 0.97 to 0.99. The adsorption of lead ions by these organoclays was investigated using different sorption models including the Langmuir, Freundlich, and BET. It was found that, according to the values of limiting adsorption to the Langmuir equation, the synthesized organoclays formed an increasing series: organoclay with cocamide diethanolamine < bentonite < organoclay with lauramine oxide < organoclay with sodium cocoiminodipropionate < organoclay with disodium cocoamphodiacetate < organoclay with alkyl polyglucoside. The Gibbs energy for all of the analyzed samples was calculated and found to be negative, indicating the spontaneity of the cation adsorption process in the forward direction. The maximum value of the adsorption capacity of lead cations on organoclay-based bentonite with alkyl polyglucoside was 1.49 ± 0.05 mmol/g according to the Langmuir model, and 0.523 ± 0.003 mmol/g as determined by the BET model. In the process of modifying bentonite, there was an increase in negative values of the zeta potential for organoclays compared to the initial mineral, which clearly enhanced their electrostatic interactions with the positively charged lead ions. It was hypothesized, based on the physicochemical principles, that exchange adsorption is the main mechanism for lead absorption. Based on chemical approaches, organoclays based on amphoteric surfactants absorb lead mainly through the mechanisms of electrostatic attraction, ion exchange, and complexation as well as the formation of insoluble precipitates. Organoclays based on nonionic surfactants, on the other hand, absorb lead through mechanisms of complexation (including chelation) and the formation of insoluble chemical precipitates. The comparison of isotherms from different models allows us to find the most accurate match between the model and the experimental data, and to better understand the nature of the processes involved.

Oxidative stress frequently contributes to intestinal barrier injury in animals and humans. It was reported that both Selenomethionine (SeMet) and allicin exhibit protective effects against a range of diseases caused by oxidative stress. This study aimed to investigate the synergistic antioxidant effects and underlying mechanisms of SeMet and allicin on a H₂O₂-induced intestinal barrier injury model using IPEC-J2 cells and mice. The results showed that H₂O₂ induced severe oxidative stress, including a decrease in cell viability, antioxidant level, migration capacity, and cell integrity. SeMet and allicin exhibited significant synergistic anti-oxidative effects on intestinal epithelial cells. The combined use of SeMet and allicin increased SOD activity, GSH content, and GSH/GSSG ratio while decreasing MDA, NO, and ROS content levels. Furthermore, we found that SeMet and allicin synergistically activated the nuclear factor erythroid-related factor 2 (Nrf2)-NAD(P)H dehydrogenase [quinone] 1 (NQO1) signaling pathway and down-regulated endoplasmic reticulum stress (ER stress)-related proteins. However, the synergistic antioxidative and intestinal barrier protective effects of SeMet and allicin were abolished by Nrf2 inhibitor ML385 in vitro and in vivo. In conclusion, SeMet and allicin synergistically attenuate intestinal barrier injury induced by excessively oxidative stress through the activation of the Nrf2 signaling pathway and inhibition ER stress. These findings support that the combined use of SeMet and allicin could enhance antioxidative properties and alleviate intestinal injury in further clinical practice.

Mercury, particularly in its methylated form, poses a significant environmental and health risk in aquatic ecosystems. While the toxicity and bioaccumulation of mercury are well documented, there remains a critical gap in our understanding of the mechanisms governing mercury methylation and demethylation in aquatic environments. This review systematically examines the complex interplay of chemical, biological, and physical factors that influence mercury speciation and transformation in natural water systems. We provide a comprehensive analysis of methylation and demethylation processes, specifically focusing on the dominant role of methanogenic bacteria. Our study highlights the crucial function of hgcAB genes in facilitating mercury methylation by anaerobic microorganisms, an area that represents a frontier in current research. By synthesizing the existing knowledge and identifying key research priorities, this review offers novel insights into the intricate dynamics of mercury cycling in aquatic ecosystems. Our findings provide a theoretical framework to inform future studies and guide pollution management strategies for mercury and its compounds in aquatic environments.