Triclosan In Water Research Articles

Pollution levels and ecological risks of PPCPs in water and sediment samples of Danjiangkou Reservoir.

The concentrations and distribution patterns of three typical pharmaceuticals and personal care products (PPCPs) in water and sediment samples obtained from Danjiangkou Reservoir during two seasonal sampling periods were studied to determine their impact on water quality. The temporal and spatial variations in concentrations measured were analyzed and related to ecological risks with data obtained during the mean-flow period (in June) and the dry period (in November). We found a high detection rate of ketoprofen (KTP) in water samples from Danjiangkou Reservoir; the concentrations ranged from not detected (ND) to 46.80ng/L with the highest values measured in the Hanku tributary samples followed by the samples collected in the main body of Danjiangkou Reservoir. The KTP concentrations in the Danku tributary samples were the lowest measured in this study. In addition, the concentrations of KTP in the Shending River, Sihe River, Jianghe River, Guanshan River, and Jianhe River water samples were relatively high in the mean-flow period. The water sample detection rates and concentrations of triclosan (TCS) and triclocarban (TCC) were low in both the mean-flow period and the dry period. All three kinds of PPCPs were detected in the sediment samples with the concentrations of KTP, TCS, and TCC ranging from 0.76 to 7.89μg/kg, 0.01 to 0.59μg/kg, and 0.01 to 11.36μg/kg, respectively. Overall, the concentrations of the three measured PPCPs in the water and sediment samples were all relatively low compared to results reported in the recent literature. The dry period concentrations of PPCPs in the water samples were lower than the concentrations measured in the mean-flow period. However, dry period concentrations were higher in the sediment samples compared to those in the mean-flow period samples. Our interpretation of the spatial and temporal patterns of PPCPs in Danjiangkou Reservoir suggests that these compounds were likely mainly derived from wastewater discharge in the upper reaches of the reservoir. The risk quotient (RQ) method was used for an ecological risk assessment of the detected PPCPs in this study. We found that TCS in water and sediment posed medium ecological risks to algae at different times of the year. In view of the extreme importance of water safety in Danjiangkou Reservoir, the ecological risks of PPCPs require additional attention.

Dynamic alterations in physiological and biochemical indicators of Cirrhinus mrigala hatchlings: A sublethal exposure of triclosan

Triclosan (TCS), a biocide used in various day-to-day products, has been associated with several toxic effects in aquatic organisms. In the present study, biochemical and hematological alterations were evaluated after 14 d (sublethal) exposure of tap water (control), acetone (solvent control), 5, 10, 20, and 50 μg/L (environmentally relevant concentrations) TCS to the embryos/hatchlings of Cirrhinus mrigala, a major freshwater carp distributed in tropic and sub-tropical areas of Asia. A concentration-dependent increase in the content of urea and protein carbonyl, while a decrease in the total protein, glucose, cholesterol, triglycerides, uric acid, and bilirubin was observed after the exposure. Hematological analysis revealed a decrease in the total erythrocyte count, hemoglobin, and partial pressure of oxygen, while there was an increase in the total leucocyte count, carbon dioxide, and partial pressure of carbon dioxide and serum electrolytes. Comet assay demonstrates a concentration-dependent increase in tail length, tail moment, olive tail moment, and percent tail DNA. An amino acid analyzer showed a TCS-dose-dependent increase in various amino acids. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis revealed different proteins ranging from 6.5 to 200 kDa, demonstrating TCS-induced upregulation. Fourier transform infrared spectra analysis exhibited a decline in peak area percents with an increase in the concentration of TCS in water. Curve fitting of amide I (1,700–1600 cm−1) showed a decline in α-helix and turns and an increase in β-sheets. Nuclear magnetic resonance study also revealed concentration-dependent alterations in the metabolites after 14 d exposure. TCS caused alterations in the biomolecules and heamatological parameters of fish, raising the possibility that small amounts of TCS may change the species richness in natural aquatic habitats. In addition, consuming TCS-contaminated fish may have detrimental effects on human health. Consequently, there is a need for the proper utilisation and disposal of this hazardous compound in legitimate quantities.

Efficient removal of triclosan from water through activated carbon adsorption and photodegradation processes

This study investigated the application of adsorption with activated carbons (ACs) and photodegradation to reduce the concentration of triclosan (TCS) in aqueous solutions. Concerning adsorption, ACs (Darco, Norit, and F400) were characterised and batch experiments were performed to elucidate the effect of pH on equilibrium. The results showed that at pH = 7, the maximum adsorption capacity of TCS onto the ACs was 18.5 mg g−1 for Darco, 16.0 mg g−1 for Norit, and 15.5 mg g−1 for F400. The diffusional kinetic model allowed an adequate interpretation of the experimental data. The effective diffusivity varied and increased with the amount of TCS adsorbed, from 1.06 to 1.68 × 10−8 cm2 s−1. In the case of photodegradation, it was possible to ensure that the triclosan molecule was sensitive to UV light of 254 nm because the removal was over 80 % using UV light. The removal of TCS increased in the presence of sulfate radicals. It was possible to identify 2,4-dichlorophenol as one of the photolytic degradation products of triclosan, which does not represent an environmental hazard at low concentrations of triclosan in water. These results confirm that the use of AC Darco, Norit, and F400 and that photodegradation processes with UV light and persulfate radicals are effective in removing TCS from water, reaching concentration levels that do not constitute a risk to human health or environmental hazard. Both methods effectively eliminate pollutants with relatively easy techniques to implement.

Eco-friendly monitoring of triclosan as an emerging antimicrobial environmental contaminant utilizing electrochemical sensors modified with CNTs nanocomposite transducer layer.

Environmental appearance of antimicrobials due to frequent use of personal care products as recommended by WHO can cause serious flare-up of antimicrobial resistance. In this work, three eco-friendly microfabricated copper solid-state sensors were developed for measuring triclosan in water. Multi-walled carbon nanotubes were incorporated in sensor 2 and 3 as hydrophobic conductive inner layer. Meanwhile, β-cyclodextrin was incorporated in sensor 3 as an ionophore for selective binding of TCS in presence of interfering compounds. The obtained linear responses of sensors 1, 2 and 3 were (1 × 10- 8-1 × 10- 3M), (1 × 10- 9-1 × 10- 3M) and (1 × 10- 10- 1 × 10- 3M), respectively. Limit of detection was 9.87 × 10- 9M, 9.62 × 10- 10M, and 9.94 × 10- 11M, respectively. The miniaturized sensors were utilized for monitoring of triclosan in water samples.

Human health risk assessment of Triclosan in water: spatial analysis of a drinking water system.

Triclosan (TCS) has been increased in the water during the COVID-19 pandemic because it cannot remove by conventional water treatment. In addition, it can accumulate in the human body over time through long-term exposure. Therefore, the occurrence of TCS in the water treatment plant (WTP) and tap water, and its human health risk assessment through tap water ingestion, dermal absorption, and inhalation routes in Isfahan, Iran, were investigated. Moreover, spatial regression methods were used for the prediction of water quality parameters, TCS concentration, and total hazard quotient (HQ). The average TCS concentration in the influent and effluent of WTP and tap water was 1.6, 1.4, and 0.4 μg/L, respectively. Conventional WTP has low efficiency in the removal of TCS (12.6%) from water. The average values of total HQ for males were 7.79×10-5, 4.97×10-4, and 4.97×10-5 and for females were 3.31×10-5, 2.11×10-4, and 2.11×10-5 based on RfDEPA, RfDMDH, and RfDRodricks, respectively that were in the low-risk levels (HQ<1). Furthermore, TCS concentration in tap water and the ingestion rate of drinking water had the highest effect on the risk of TCS exposure from tap water. The non-carcinogenic health risk of TCS in water was low. The results of this study may be useful for promoting WTP processes to remove emerging pollutants.

Thermally regenerable FeS/N-doped biochar catalyzed peroxydisulfate oxidative destruction of aqueous triclosan

Ferrous sulfide loaded on N-doped biochar (FeS/NBC) was prepared to pyrolyze jute fibers pretreated with (NH4)2Fe(SO4)2. FeS/NBC-catalyzed degradation of triclosan was assessed by peroxydisulfate oxidation. The effects of solution pH, foreign anions and peroxydisulfate concentration were investigated. It is found that neutral pH was conducive to removal of triclosan, achieving about 99% triclosan removal and 65% mineralization level. The presence of HCO3− and HPO42− will inhibit triclosan degradation, but Cl− showed a considerable promotion. Importantly, the spent FeS/NBC catalyst can be regenerated via a reheat treatment to completely recover the catalytic activity. Electron paramagnetic resonance and quenching experiments demonstrated that radicals (OH, SO4−O2−) and non-radical (1O2) were the major reactive species in the reaction. GC–MS analysis identified that the residual intermediates from cycloaddition and ether bond breakage existed in the reaction solution, and recommended radical-dominated and singlet oxygen-assisted degradation pathways. The evaluation of actual samples showed that the presence of Cl− could enhance the removal of triclosan, and the generation of chlorine-based radicals was suggested as the main reason for this result. This study proved FeS/NBC-PDS system could efficiently remove triclosan in water, and the catalyst can be regenerated by a simple reheat treatment.

Day-night alternation and effect of sulfate ions on photodegradation of triclosan in water

Photodegradation is an essential process for the in-stream elimination of triclosan (TCS). There are still some knowledge gaps concerning reaction kinetics, pathways, and transformation products, which are important for understanding the environmental fate of TCS. For example, the effects of ionic strength and day-night alternation on TCS photodegradation have been barely considered in previous studies. To fill these gaps, this study assesses the effect of sulfate ions (SO42−) on the photodegradation of TCS under day-night shifts. Compound-specific carbon and chlorine isotope analysis were applied to characterize different bond-cleavage pathways. Moreover, variations in TCS reaction products distribution were analyzed by using Fourier transform ion cyclotron resonance mass spectrometry. A numerical model was developed to describe the concentration and stable carbon isotopic evolution of TCS under different conditions. Based on the observed experimental data, we show that SO42− can affect the kinetics and product distribution during the photodegradation of TCS. In particular, sulfate ions (100 mM) inhibited the yield of the toxic product, 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD). Furthermore, day-night alternations lead to different predominant bond-cleavage pathways depending on sulfate concentration. By so doing, we propose a realistic framework for the direct photodegradation of TCS in sunlit natural surface waters.

Ultrasensitive Surface‐Enhanced Raman Spectroscopy Detection by Porous Silver Supraparticles from Self–Lubricating Drop Evaporation

AbstractThis work demonstrates an original and ultrasensitive approach for surface‐enhanced Raman spectroscopy (SERS) detection based on evaporation of self‐lubricating drops containing silver supraparticles. The developed method detects an extremely low concentration of analyte that is enriched and concentrated on sensitive SERS sites of the compact supraparticles formed from drop evaporation. A low limit of detection of 10−16 m is achieved for a model hydrophobic compound rhodamine 6G (R6G). The quantitative analysis of R6G concentration is obtained from 10−5 to 10−11 m. In addition, for a model micro‐pollutant in water triclosan, the detection limit of 10−6 m is achieved by using microliter sample solutions. The intensity of SERS detection in this approach is robust to the dispersity of the nanoparticles in the drop but became stronger after a longer drying time. The ultrasensitive detection mechanism is the sequential process of concentration, extraction, and absorption of the analyte during evaporation of self‐lubrication drop and hot spot generation for intensification of SERS signals. This novel approach for sample preparation in ultrasensitive SERS detection can be applied to the detection of chemical and biological signatures in areas such as environment monitoring, food safety, and biomedical diagnostics.

Study of microplastics as sorbents for rapid detection of multiple antibiotics in water based on SERS technology

Online monitoring of antibiotics in the environment attracts more and more attention. Surface-enhanced Raman scattering (SERS) is a promising technique for the detection of trace amounts of antibiotics in the environment, which is fast, non-invasive and sensitive. To investigate the enrichment of trace amounts of antibiotics in water, polyethylene microplastics (PE MPs) were prepared as sorbents to simply concentrate enrofloxacin, ciprofloxacin hydrochloride monohydrate and triclosan in water, followed by the SERS measurement of antibiotics extract washed from MPs on an AgNPs@Si SERS substrate. Limit of detection of Rhodamine 6G is 2.1 × 10-12 M achieved from the AgNPs@Si SERS, indicating a high enhancement. The detection results show that SERS peaks of the antibiotics could be observed from the spectra of the extracts eluted from MPs, indicating MPs could adsorb and desorb antibiotics from water. Besides, for enrofloxacin and triclosan, the intensity of SERS measured from the MPs extracts are higher than that of directly from the spiked water, demonstrating the proposed method could lower the detectable concentration of hydrophobic antibiotics in water. Moreover, the proposed MPs sorbents combined with SERS method was applied to detect the antibiotics in real river water, with minimal detection of 10-10 M, 10-8 M, and 10-8 M achieved for enrofloxacin, ciprofloxacin hydrochloride monohydrate and triclosan, respectively. The proposed method provides a promising simple, rapid and low reagent consuming means for monitoring antibiotics in water.

An Ionic-Liquid-Imprinted Nanocomposite Adsorbent: Simulation, Kinetics and Thermodynamic Studies of Triclosan Endocrine Disturbing Water Contaminant Removal.

The presence of triclosan in water is toxic to human beings, hazardous to the environment and creates side effects and problems because this is an endocrine-disturbing water pollutant. Therefore, there is a great need for the separation of this notorious water pollutant at an effective, economic and eco-friendly level. The interface sorption was achieved on synthesized ionic liquid-based nanocomposites. An N-methyl butyl imidazolium bromide ionic liquid copper oxide nanocomposite was prepared using green methods and characterized by using proper spectroscopic methods. The nanocomposite was used to remove triclosan in water with the best conditions of time 30 min, concentration 100 µg/L, pH 8.0, dose 1.0 g/L and temperature 25 °C, with 90.2 µg/g removal capacity. The results obeyed Langmuir, Temkin and D-Rs isotherms with a first-order kinetic and liquid-film-diffusion kinetic model. The positive entropy value was 0.47 kJ/mol K, while the negative value of enthalpy was −0.11 kJ/mol. The negative values of free energy were −53.18, −74.17 and −76.14 kJ/mol at 20, 25 and 30 °C. These values confirmed exothermic and spontaneous sorption of triclosan. The combined effects of 3D parameters were also discussed. The supramolecular model was developed by simulation and chemical studies and suggested electrovalent bonding between triclosan and N-methyl butyl imidazolium bromide ionic liquid. Finally, this method is assumed as valuable for the elimination of triclosan in water.

Influence of microplastics on triclosan bioaccumulation and metabolomics variation in Tilapia fish tissues.

Microplastics (MPs) and chemical pollutants usually coexist in aquatic environments. The bioaccumulation and metabolism of pollutants in aquatic organisms can be influenced by MPs. In this study, the bioaccumulation of triclosan (TCS) in tilapia tissues was determined, and metabolomics in the liver, gills, and gut were investigated after 10-day exposure to micro-sized polystyrene (PS) and TCS in water. The results showed that TCS bioaccumulated in various tissues, with the highest average concentration of 2728 ± 577 ng g-1 in the gut. The log bioaccumulation factors (BAFs) for TCS in these tissues were in the range of 0.99-3.56. Compared to the TCS treatment alone, MPs showed enhancement on the bioaccumulation of TCS in tilapia skin, liver, gut, gills, and stomach tissues in the TCS plus MP exposure. Especially in the skin and liver, the TCS concentrations were up to 2.06 and 1.38 times higher in the co-exposure of TCS and MPs, respectively. Based on the metabolomic analysis, MPs mainly disturbed the lipid and energy metabolism in tilapia fish. The altered metabolites between treatment with TCS alone and TCS + MPs were consistent, indicating that TCS has stronger disturbance in lipid and energy metabolism than MPs. This implies that the metabolism influence by the mixture of MPs and compounds is complicated in fish tissues.

Cork-based passive samplers for monitoring triclosan in water samples

Novel passive samplers based on cork as a sorbent phase were implemented for the sampling and preconcentration of triclosan in water. Two sampler configurations were developed: The larger sampler (cork passive sampler, CPS) involved a Teflon casing to protect a circular laminar cork phase with a diameter of 4.5 cm, which was covered by polyethersulfone membranes. In the smaller sampler (miniaturized cork sampler, MCS), a circular piece of cork with a diameter of 0.8 cm was directly exposed in the water samples.

Fate, bioaccumulation and toxic effects of triclosan on a freshwater community – A mesocosm study

The antibacterial agent triclosan (TCS) is added to many daily-used consumer products and can therefore reach the aquatic environment via treated wastewater and potentially harm aquatic ecosystems. A 120 days pond mesocosm study was conducted in order to investigate the fate of TCS in water and sediment, its bioaccumulative potential in different biota as well as the effects of TCS and its main transformation product methyl-triclosan (M-TCS) on plankton, periphyton, macrophytes, and benthos communities. TCS was dosed once each in six pond mesocosms (nominal concentrations: 0.12, 0.6, 3.5, 21, 130 and 778 µg/L TCS, respectively) while two ponds served as controls. A concentration-dependent increase in the DT50 values from 5.0 to 15.0 and 7.5 to 16.3 days was observed for TCS in water and the whole pond system (water, sediment, biota), respectively. Consequently, the substance should be categorized as non-persistent. For TCS, the bioaccumulation factors (non steady-state conditions, BAFnssc) in Lymnaea stagnalis, Myriophyllum spicatum and periphyton were below the critical limit of 2000, above which a substance is classified as bioaccumulative. In contrast, a BAFnssc value of >10,000 was found for M-TCS in L. stagnalis, denoting that M-TCS definitely falls under this classification. Although strong effects on freshwater communities could only be observed in the highest TCS treatments, some periphyton species, such as Oedogonium spp., reacted very sensitive to TCS with an EC50 (time weighted average, 28 d) of 0.3 µg/L TCS. Considering the high bioaccumulative potential of M-TCS in combination with the observed effects of TCS at low doses suggests that the use of TCS, and therefore its release into the environment, should cease.

Photodegradation of fragrance materials and triclosan in water: Direct photolysis and photosensitized degradation

The present study aims to assess the photodegradation of three polycyclic musk compounds (OTNE, HHCB, and AHTN) and one disinfectant (triclosan) under simulated sunlight irradiation using a halogen lamp in pH-adjusted DI water, natural waters, and humic acid solution. The degradation induced by hydroxyl radical was examined with the addition of 2-propanol. The targeted compounds were considerably decreased in several days under irradiation, except for triclosan for blank water, with the pseudo-first-order rate constants in the order of one per day at the maximum. They were degraded with the paths of both direct and indirect photosensitized processes, with the hydroxyl radical and others. The main findings were that OTNE direct photolysis was possibly influenced by pH. HHCB photosensitized pathway was more eminent than that of AHTN, and triclosan was degraded mostly by the photosensitized process. The major influential factors were found to differ with the compounds and solution conditions, which intensifies the importance of the consideration of key factors for predicting the degree of photodegradation in water environments. • Direct photolysis and photosensitized degradation were evaluated simultaneously. • Triclosan was mostly degraded by photosensitized pathway, not by direct photolysis. • ONTE direct photolysis was influenced by pH.

Flexible reusable hierarchical hybrid catalyst for rapid and complete degradation of triclosan in water

A flexible, durable, and reusable nanocatalyst system was fabricated by anchoring palladium nanoparticles on carbon nanotube (CNT) carpets covalently attached to carbon cloth. These hierarchical hybrid materials were tested for catalytic degradation of triclosan (TCS), an emerging contaminant. Materials were characterized using scanning & transmission electron microscopy techniques (SEM and TEM), X-Ray Diffraction (XRD), and X-Ray Photoelectron Spectroscopy (XPS). The reaction kinetics was studied using HPLC and reaction pathways proposed based on LC-MS/GC-MS analyses. In the presence of hydrogen, complete step-wise chlorine removal was seen until complete dechlorination was accomplished. The pseudo-first-order rate constant was measured to be orders of magnitude higher than earlier reported values. Moreover, the same material was usable for multiple cycles in flowing water. This study demonstrates that robustness and reusability of larger structural materials can be combined with the ultra-high surface activity of nanocatalysts to provide practical and eco-friendly solutions for water sustainability.

Ultrasonic-enhanced nascent H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; activation on Raney Ni for the degradation of triclosan

<p indent=0mm>Triclosan (TCS) is a broad-spectrum antibacterial agent that has been widely used in medicines and personal care products, such as fungicide, disinfectants, soap, toothpaste, etc. Most of the products containing TCS after use enter the sewage treatment plant through domestic sewage. However, TCS entering the sewage treatment plant is only partially degraded due to its stable halogenated aromatic structure, and the remaining TCS and its by-products will enter the external environment. Studies have found that TCS in the aquatic environment exhibits significant biological toxicity to the growth and metabolism of algae, luminescent bacteria, zooplankton and fish. In addition, TCS will cause allergic dermatitis through direct contact with the human body through skin and oral cavity, and can also indirectly accumulate in the body through the food chain, thereby disrupting the body’s normal endocrine function. The development of efficient treatment technology for TCS in water has important theoretical significance and application value. Reductive dechlorination can effectively reduce the toxicity and stability of TCS (improve its biodegradability), and plays an important role in the restoration of TCS polluted water. The currently used reduction techniques include zero-valent iron reduction, electrochemical reduction, photochemical reduction and catalytic hydrogenation. Among them, catalytic hydrogenation has attracted wide attention due to its simple operation and high efficiency. However, its upscale application is being restricted by its excessive dependence on noble metal catalysts and the closed high-pressure environment constructed to improve hydrogenation efficiency. This work aims to improve the existing catalytic hydrogenation technology. Specifically, cheap and available Raney Ni (R-Ni) was selected as the hydrogenation catalyst, and tiny nascent H₂ (Nas-H₂) bubbles generated <italic>in situ</italic> by the cathode hydrogen evolution reaction were used as the hydrogen source. The effects of current density and catalyst dosage on TCS hydrodechlorination were studied. The experimental results showed that the reduction process of TCS in the R-Ni/Nas-H₂ system followed a pseudo-first order reaction kinetics. The conversion and dechlorination ratios of TCS (<italic>C</italic>₀=<sc>30 mg/L)</sc> were 96.3% and 68.8%, respectively, within <sc>2.0 h.</sc> Compared with the existing catalytic hydrogenation system, H₂ consumption was significantly reduced (from ≥<sc>10 mL/min</sc> to <sc>1.05 mL/min),</sc> which was attributed to that the refined Nas-H₂ bubbles were more likely to be activated by R-Ni due to their higher solubility and longer residence time in the reaction liquid. Furthermore, ultrasonic cavitation was introduced to achieve deep dechlorination of TCS. The conversion and dechlorination ratios of TCS increased to 99.0% and 86.5%, respectively, with <sc>0.58 W/cm³</sc> ultrasonic power density of the reaction solution, and the atom utilization ratio of Nas-H₂ reached 0.21%. TCS reduction conformed to the catalytic hydrogenation mechanism of adsorption→activation→hydrogenation, and the hydrogen adatoms (H_ads*) were reactive species. The ultrasound-enhanced hydrogenation performance was attributed to the cavitation which improved the catalytic activity of R-Ni and blasted Nas-H₂ into easily activatable nanoscale hydrogen (Nano-H₂), thereby promoting the production of H_ads* and increasing the effective number of collisions between reactive species (H_ads*, TCS_ads). In addition, through the determination and analysis of the reaction intermediate products, the stepwise hydrodechlorination removal mechanism of TCS was proposed, and the final product was 2-hydroxydiphenyl ether. This research is expected to be applied to the efficient dehalogenation of polyhalogenated organic pollutants in water.

Effects of triclosan on the RedoximiRs/Sirtuin/Nrf2/ARE signaling pathway in mosquitofish (Gambusia affinis)

Triclosan (TCS) has been widely used in daily life for its broad-spectrum antibacterial property and subsequently detected frequently in aquatic waterborne. Environmental relevant concentrations of TCS in water (ng-μg/L) may pose potential unexpected impact on non-target aquatic organisms. In the present work, we investigated the transcriptional responses of Nrf2 as well as its downstream genes, sirtuins and redox-sensitive microRNAs (RedoximiRs) in livers of the small freshwater fish mosquitofish (Gambusia affinis) which were exposed to environmental relevant concentrations of TCS (0.05 μg/L, 0.5 μg/L and 5 μg/L for 24 h and 168 h). Results showed there were similar up-regulations in Nrf2 and its target genes (e. g. NQO1, CAT and SOD) at transcriptional, enzymatic and protein levels, reflecting oxidative stress of TCS to mosquitofish. Meanwhile, up-regulations of Sirt1, Sirt2 and down-regulations of miR-34b, miR-200b-5p and miR-21 could modulate antioxidant system via the Nrf2/ARE signaling pathway by the post-transcriptional regulations. Some oxidative stress-related biomarkers displayed in concentration-dependent manners (e. g. NQO1 mRNA, CAT mRNA) and/or time-dependent manners (e. g. GSH contents). This study indicated that the RedoximiRs/Sirtuin/Nrf2/ARE signaling pathway played a crucial role in mosquitofish exposed to TCS, and there might be potentially profound effects for TCS on the aquatic ecological safety.

Occurrence and Safety Evaluation of Antimicrobial Compounds Triclosan and Triclocarban in Water and Fishes of the Multitrophic Niche of River Torsa, India.

Personal care product (PCP) chemicals have a greater chance of accumulation in the aquatic environments because of their volume of use. PCPs are biologically active substances that can exert an adverse effect on the ecology and food safety. Information on the status of these substances in Indian open water ecosystems is scarce. In this paper, we report the incidence of two synthetic antimicrobials, triclosan (TCS), including its metabolite methyl-triclosan (Me-TCS) and triclocarban (TCC) in Torsa, a transboundary river flowing through India. In water TCS and TCC were detected at levels exceeding their respective PNEC (Predictive No Effect Concentration). Both the compounds were found to be bioaccumulative in fish. TCS concentration (91.1-589µg/kg) in fish was higher than that of TCC (29.1-285.5µg/kg). The accumulation of residues of the biocides varied widely among fishes of different species, ecological niche, and feeding habits. Me-TCS could be detected in fishes and not in water. The environmental hazard quotient of both TCS and TCC in water indicated a moderate risk. However, the health risk analysis revealed that fishes of the river would not pose any direct hazard to human when consumed. This is the first report of the occurrence of these PCP chemicals in a torrential river system of the eastern Himalayan region.

Impact of Potential COVID-19 Treatment on South African Water Sources Already Threatened by Pharmaceutical Pollution.

After a cluster of human pneumonia cases in Wuhan City (China) on 7 January 2020 a novel coronavirus, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) was identified as the causative agent of the disease COVID‐19 (World Health Organization (WHO). 2020).This article is protected by copyright. All rights reserved.

Impact of fullerenes in the bioaccumulation and biotransformation of venlafaxine, diuron and triclosan in river biofilms

A huge variety of organic microcontaminants are presently detected in freshwater ecosystems, but there is still a lack of knowledge about their interactions, either with living organisms or with other contaminants. Actually, carbon nanomaterials like fullerenes (C60) can act as carriers of organic microcontaminants, but their relevance in processes like bioaccumulation and biotransformation of organic microcontaminants by organisms is unknown. In this study, mesocosm experiments were used to assess the bioaccumulation and biotransformation of three organic microcontaminants (venlafaxine, diuron and triclosan) in river biofilms, and to understand how much the concomitant presence of C60 at environmental relevant concentrations could impact these processes. Results indicated that venlafaxine exhibited the highest bioaccumulation (13% of the initial concentration of venlafaxine in water), while biotransformation was more evident for triclosan (5% of the initial concentration of triclosan in water). Furthermore, biotransformation products such as methyl-triclosan were also present in the biofilm, with levels up to 42% of the concentration of accumulated triclosan. The presence of C60 did not involve relevant changes in the bioaccumulation and biotransformation of microcontaminants in biofilms, which showed similar patterns. Nevertheless, the study shows that a detailed evaluation of the partition of the organic microcontaminants and their transformation products in freshwater systems are important to better understand the impact of the co-existence of others microcontaminants, like carbon nanomaterials, in their possible routes of bioaccumulation and biotransformation.