GC/MS analysis of triclosan and its degradation by-products in wastewater and sludge samples from different treatments

Potential application of 2D nano-layered MXene in analysing and remediating endocrine disruptor compounds and heavy metals in water

With the advancement of technologies and growth of the economy, it is inevitable that more complex processes are deployed, producing more heterogeneous wastewater that comes from biomedical, biochemical and various biotechnological industries. While the conventional way of wastewater treatment could effectively reduce the chemical oxygen demand, pH and turbidity of wastewater, trace pollutants, specifically the endocrine disruptor compounds (EDCs) that exist in µg L-1 or ng L-1 have further hardened the detection and removal of these biochemical pollutants. Even in small amounts, EDC could interfere human's hormone, causing severe implications on human body. Hence, this review elucidates the recent insights regarding the effectiveness of an advanced 2D material based on titanium carbide (Ti3C2Tx), also known as MXene, in detecting and removing EDCs. MXene's highly tunable feature also allows its surface chemistry to be adjusted by adding chemicals with different functional groups to adsorb different kinds of EDCs for biochemical pollution mitigation. At the same time, the incorporation of MXene into sample matrices also further eases the analysis of trace pollutants down to ng L-1 levels, thereby making way for a more cleaner and comprehensive wastewater treatment. In that sense, this review also highlights the progress in synthesizing MXene from the conventional method to the more modern approaches, together with their respective key parameters. To further understand and attest to the efficacy of MXene, the limitations and current gaps of this potential agent are also accentuated, targeting to seek resolutions for a more sustainable application.

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- 3 M), (1 × 10- 9-1 × 10- 3 M) and (1 × 10- 10- 1 × 10- 3 M), respectively. Limit of detection was 9.87 × 10- 9 M, 9.62 × 10- 10 M, and 9.94 × 10- 11 M, respectively. The miniaturized sensors were utilized for monitoring of triclosan in water samples.

Triclosan and related compounds in the environment: Recent updates on sources, fates, distribution, analytical extraction, analysis, and removal techniques

Triclosan (TCS) has been widely used in daily life because of its broad-spectrum antibacterial activities. The residue of TCS and related compounds in the environment is one of the critical environmental safety problems, and the pandemic of COVID-19 aggravates the accumulation of TCS and related compounds in the environment. Therefore, detecting TCS and related compound residues in the environment is of great significance to human health and environmental safety. The distribution of TCS and related compounds are slightly different worldwide, and the removal methods also have advantages and disadvantages. This paper summarized the research progress on the source, distribution, degradation, analytical extraction, detection, and removal techniques of TCS and related compounds in different environmental samples. The commonly used analytical extraction methods for TCS and related compounds include solid-phase extraction, liquid-liquid extraction, solid-phase microextraction, liquid-phase microextraction, and so on. The determination methods include liquid chromatography coupled with different detectors, gas chromatography and related methods, sensors, electrochemical method, capillary electrophoresis. The removal techniques in various environmental samples mainly include biodegradation, advanced oxidation, and adsorption methods. Besides, both the pros and cons of different techniques have been compared and summarized, and the development and prospect of each technique have been given.

Enzyme-Linked Metal Organic Frameworks for Biocatalytic Degradation of Antibiotics

Metal organic frameworks (MOFs) are multi-dimensional network of crystalline material held together by bonding of metal atoms and organic ligands. Owing to unique structural, chemical, and physical properties, MOFs has been used for enzyme immobilization to be employed in different catalytic process, including catalytic degradation of antibiotics. Immobilization process other than providing large surface provides enzyme with enhanced stability, catalytic activity, reusability, and selectivity. There are various approaches of enzyme immobilization over MOFs including physical adsorption, chemical bonding, diffusion and in situ encapsulation. In situ encapsulation is one the best approach that provides extra stability from unfolding and denaturation in harsh industrial conditions. Presence of antibiotic in environment is highly damaging for human in particular and ecosystem in general. Different methods such as ozonation, oxidation, chlorination and catalysis are available for degradation or removal of antibiotics from environment, however these are associated with several issues. Contrary to these, enzyme immobilized MOFs are novel system to be used in catalytic degradation of antibiotics. Enzyme@MOFs are more stable, reusable and more efficient owing to additional support of MOFs to natural enzymes in well-established process of photocatalysis for degradation of antibiotics aimed at environmental remediation. Prime focus of this review is to present catalytic degradation of antibiotics by enzyme@MOFs while outlining their synthetics approaches, characterization, and mechanism of degradation. Furthermore, this review highlights the significance of enzyme@MOFs system for antibiotics degradation in particular and environmental remediation in general. Current challenges and future perspective of research in this field are also outlined along with concluding comments.

Graphical Abstract

Comprehensive insight into triclosan-from widespread occurrence to health outcomes

Humans are exposed to the variety of emerging environmental pollutant in everyday life. The special concern is paid to endocrine disrupting chemicals especially to triclosan which could interfere with normal hormonal functions. Triclosan could be found in numerous commercial products such as mouthwashes, toothpastes and disinfectants due to its antibacterial and antifungal effects. Considering the excessive use and disposal, wastewaters are recognized as the main source of triclosan in the aquatic environment. As a result of the incomplete removal, triclosan residues reach surface water and even groundwater. Triclosan has potential to accumulate in sediment and aquatic organisms. Therefore, the detectable concentrations of triclosan in various environmental and biological matrices emerged concerns about the potential toxicity. Triclosan impairs thyroid homeostasis and could be associated with neurodevelopment impairment, metabolic disorders, cardiotoxicity and the increased cancer risk. The growing resistance of the vast groups of bacteria, the evidenced toxicity on different aquatic organisms, its adverse health effects observed in vitro, in vivo as well as the available epidemiological studies suggest that further efforts to monitor triclosan toxicity at environmental levels are necessary. The safety precaution measures and full commitment to proper legislation in compliance with the environmental protection are needed in order to obtain triclosan good ecological status. This paper is an overview of the possible negative triclosan effects on human health. Sources of exposure to triclosan, methods and levels of detection in aquatic environment are also discussed.

Surface Nanodroplet-Based Extraction Combined with Offline Analytic Techniques for Chemical Detection and Quantification

Liquid-liquid extraction based on surface nanodroplets can be a green and sustainable technique to extract and concentrate analytes from a sample flow. However, because of the extremely small volume of each droplet (<10 fL, tens of micrometers in base radius and a few or less than 1 μm in height), only a few in situ analytical techniques, such as surface-enhanced Raman spectroscopy, were applicable for the online detection and analysis based on nanodroplet extraction. To demonstrate the versatility of surface nanodroplet-based extraction, in this work, the formation of octanol surface nanodroplets and extraction were performed inside a 3 m Teflon capillary tube. After extraction, surface nanodroplets were collected by injecting air into the tube, by which the contact line of surface droplets was collected by the capillary force. As the capillary allows for the formation of ∼10¹² surface nanodroplets on the capillary wall, ≥2 mL of octanol can be collected after extraction. The volume of the collected octanol was enough for the analysis of offline analytical techniques such as UV-vis, GC-MS, and others. Coupled with UV-vis, reliable extraction and detection of two common water pollutants, triclosan and chlorpyrifos, was shown by a linear relationship between the analyte concentration in the sample solution and UV-vis absorbance. Moreover, the limit of detection (LOD) as low as 2 × 10^-9 M for triclosan (∼0.58 μg/L) and 3 × 10^-9 M for chlorpyrifos (∼1.05 μg/L) could be achieved. The collected surface droplets were also analyzed via gas chromatography (GC) and fluorescence microscopy. Our work shows that surface nanodroplet extraction may potentially streamline the process in sample pretreatment for sensitive chemical detection and quantification by using common analytic tools.

Formation of environmentally persistent free radicals from thermochemical reactions of catechol

In many anthropogenic activities, catechol as a widespread organic chemical could be released and also environmentally persistent free radicals (EPFRs) can be unintentionally formed. However, the underlying links between EPFRs and the role of catechol as an important precursor are not well understood. In this study, EPFR formation from catechol during heating was monitored online by electron paramagnetic resonance spectroscopy. It was found that catechol can produce significant amounts of EPFRs via thermochemical reactions. The EPFR species formed from catechol on metal oxides were oxygen-centered phenoxy and semiquinone radicals. Their half-lives were evaluated to be in the range of 113-909 h. The promotional effects of CaO and CuO on EPFR formation from catechol were stronger than that of Fe₂O₃. The promotional abilities and underlying mechanisms of various metal oxides in EPFR formation were clarified by X-ray photoelectron spectroscopy. Significant EPFR formation was observed during the cooling stage of a heating reaction system when CaO was used as the reaction medium. The obtained knowledge on the formation of EPFRs from catechol and the key factors involved will enable better control of the formation of EPFRs from anthropogenic activities.

Sensitive and selective determination of triclosan using visual spectroscopy

Triclosan is a commonly used biocide effective against bacterial and fungal infections. However, its overuse in pharmaceutical and personal care products has resulted in its abundance in the natural environment. The detection of triclosan by visual spectroscopy can be carried out using the azo-coupling reaction of diazonium complexes. However, the reaction is also common to other phenolic compounds and aromatic amines, posing significant challenge. In this work, we investigate the azo-coupling reaction of triclosan and several commonly occurring analogous compounds to develop an improved spectroscopic method for the selective determination of triclosan without interference. We find that the azo-coupling reaction between the diazotized derivative and the phenolic compounds is highly dependent on the pH of the reaction media. At pH 7.2, the absorbance of the azo dye product of triclosan shows a peak at 452 nm which has minimal interference from other phenolic azo-dye products with the exception of naphthol. Naphthol shows an interference corresponding to 58% of the analytical signal of equimolar triclosan concentration. To overcome this, we develop an analytical model for the simultaneous determination of triclosan and naphthol from mixed solutions of the compounds. A linear calibration plot from 1.7 to 34 µM was obtained for both triclosan and naphthol with limit-of-detection (LOD) of 0.62 µM and 1.03 µM respectively. The developed protocol was tested for the analysis of water samples collected from various environmental sources spiked with different concentrations of triclosan and naphthol. The samples were enriched by solid-phase-extraction which allowed a 50-fold enhancement in detection of triclosan. The average relative recovery of triclosan in real samples was found to be 98.6% .

In situ monitoring of triclosan in environmental water with subnanomolar detection limits using eco-friendly electrochemical sensors modified with cyclodextrins

The environmental emergence of unexpected contaminants has gained the attention of the scientific community. A broad spectrum antimicrobial compound named triclosan (TCS) was detected in the environment as an emerging contaminant. Owing to its inherent toxicity, we have proposed eco-friendly potentiometric liquid state sensors to be used for monitoring and quantifying TCS in environmental water samples. The proposed sensors have been optimized by modifying the inner filling solution using hydrophilic 2-hydroxypropyl β-cyclodextrin as a complexing agent to be capable of minimizing the trans-membrane ion flux and hence improving the selective and sensitive determination of TCS in environmental matrices with low LOD values. The obtained linear response of the optimized sensor was (1 × 10^-9 to 1 × 10^-5 M) compared to the control sensor (1 × 10^-8 to 1 × 10^-4 M). The obtained limit of detection (LOD) value was found to be 9.86 × 10^-10 M compared to 9.78 × 10^-9 M of the control sensor. The modification of the inner filling solution of the sensor with 2-hydroxypropyl β-cyclodextrin improves not only its sensitivity but also its response time to be only 5 seconds. The electrical performance of the proposed sensor was evaluated following IUPAC recommendations. Both the pH and temperature effects were studied and optimized. Two different greenness assessment tools, Analytical Eco-scale and Green Procedure Index, were adopted upon the evaluation of the proposed sensors' greenness.

A Review on the Fate of Legacy and Alternative Antimicrobials and Their Metabolites during Wastewater and Sludge Treatment

Antimicrobial compounds are used in a broad range of personal care, consumer and healthcare products and are frequently encountered in modern life. The use of these compounds is being reexamined as their safety, effectiveness and necessity are increasingly being questioned by regulators and consumers alike. Wastewater often contains significant amounts of these chemicals, much of which ends up being released into the environment as existing wastewater and sludge treatment processes are simply not designed to treat many of these contaminants. Furthermore, many biotic and abiotic processes during wastewater treatment can generate significant quantities of potentially toxic and persistent antimicrobial metabolites and byproducts, many of which may be even more concerning than their parent antimicrobials. This review article explores the occurrence and fate of two of the most common legacy antimicrobials, triclosan and triclocarban, their metabolites/byproducts during wastewater and sludge treatment and their potential impacts on the environment. This article also explores the fate and transformation of emerging alternative antimicrobials and addresses some of the growing concerns regarding these compounds. This is becoming increasingly important as consumers and regulators alike shift away from legacy antimicrobials to alternative chemicals which may have similar environmental and human health concerns.

Does salinity variation increase synergistic effects of triclosan and carbon nanotubes on Mytilus galloprovincialis? Responses on adult tissues and sperms

The use of carbon nanotubes (CNTs) is rapidly increasing and several scientific studies have addressed their toxicological properties. However, only a very small number of publications have deal with the interaction between CNTs and other molecules. Triclosan (TCS) is an antibacterial agent used in personal care and household products. Commonly detected in aquatic ecosystems, there is a strong evidence that aquatic biota is sensitive to this compound. Aside from emergent pollutants, aquatic organisms are continuously subjected to abiotic variations including salinities. Therefore, the main goal of the present study was to better understand how physio-chemical interactions of CNTs with TCS under different salinity levels (37, 28 and 19) affect the mussel species Mytilus galloprovincialis through the evaluation of biochemical alterations on gametes (sperms) and adult tissues, providing more ecologically relevant information on organisms' responses. The results showed toxicological effects in terms of sperm metabolic activity and intracellular reactive oxygen species production as well as cellular damage and alteration of metabolic capacity at the adult's stage when exposed to both contaminants acting alone and in combination, under tested salinities. Moreover, when the mussels were exposed to the combination of both contaminants, they showed major toxic impacts on both assessed biological levels (adult tissues and sperms) especially under control salinity. This suggests that toxicity upon mixture exposure compared to single-substance exposure may impair mussels' populations, affecting reproduction success and growth.

Wastewater monitoring by means of e-nose, VE-tongue, TD-GC-MS, and SPME-GC-MS

The presence of wastewater and air pollution has become an important risk factor for citizens, not only in terms of problems related to health risks, but also because of its negative impact on the country's image. For this reason, malodorous emission monitoring and control techniques are in high demand in urban areas and industries. The aim of this work is first to build an electronic nose (e-nose) and a Voltammetric Electronic tongue (VE-tongue) in order to study their ability to discriminate between polluted and clean environmental samples. Secondly, Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS), and Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS) are utilized to explain this discrimination by identifying specific compounds from these samples. Indeed, the e-nose, consisted of metal oxide semiconductor gas sensors, is used for the assessment of the studied odorous air and headspace samples from water and wastewater sites. Moreover, the VE-tongue, based on metal electrodes, is utilized to determine the patterns of the sensor array responses, which serve as fingerprints profiles of the analyzed liquid samples. Chemometric tools, such as Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Support Vector Machines (SVMs) are operated for the processing of data from the e-nose and the VE-tongue. By using the both systems, the analyses of headspace and liquid samples from the seven sites allow better discrimination. To explain the cause of the obtained discrimination, TD-GC-MS and SPME-GC-MS analyses are well performed to identify compounds related sites. According to these outcomes, the proposed e-nose and VE-tongue are proved to be rapid and valuable tools for analysis of environmental polluted matrices.

Recent progresses in analytical GC and LC mass spectrometric based-methods for the detection of emerging chlorinated and brominated contaminants and their transformation products in aquatic environment

This paper is an overview of screening methods recently developed for emerging halogenated contaminants and their transformation products. The target screening methods are available only for a limited number of emerging pollutants since the reference standards for these compounds are not always available, but a risk assessment of those micropollutants in environment must be performed anyhow. Therefore, the chromatographic techniques hyphenated with high resolution mass spectrometry (HRMS) trend to become indispensable methods for suspect and non-target screening of emerging halogenated contaminants. HRMS is also an effective tool for tentatively identification of the micropollutants' transformation products existing in much lower concentrations. To assess the transformation pathway of halogenated contaminants in environment, the non-target screening methods must be combined with biodegradation lab experiments and also with advanced oxidation and reduction processes that can mimic the transformation on these contaminants in environment. It is expected that in the future, the accurate-mass full-spectra of transformation products recorded by HRMS will be the basic information needed to elucidate the transformation pathways of emerging halogenated contaminants in aquatic environment.

DNA-based stable isotope probing identifies triclosan degraders in nitrification systems under different surfactants

Three widely-used surfactants, rhamnolipid (RL), sophorolipid (SL) and sodium dodecyl benzene sulfonate (SDBS), were chosen to investigate their effects on the nitrification systems treating step-wised triclosan (TCS). Surfactants had little effects on nitrification. Surfactants could promote the desorption of TCS and enhance the TCS biodegradation in nitrification systems. And TCS biodegradation efficiencies obtained with RL, SL and SDBS were 1.25, 1.23 and 1.14 times higher than the control with 9.0 mg/L TCS, respectively. Illumina MiSeq sequencing showed that Amaricoccus could be resistant to TCS. And Amaricoccus, detected with RL, SL and SDBS, were more abundant than the control. DNA-based stable isotope probing assays revealed Amaricoccus was the major TCS degrader. And the addition of surfactants could obviously increase the diversity of active TCS degraders, especially for biosurfactants. It seems that the addition of surfactants showed positive effects for the nitrification systems treating TCS wastewater.

Polyelectrolyte Based Sensors as Key to Achieve Quantitative Electronic Tongues: Detection of Triclosan on Aqueous Environmental Matrices

Triclosan (TCS) is a bacteriostatic used in household items that promotes antimicrobial resistance and endocrine disruption effects both to humans and biota, raising health concerns. In this sense, new devices for its continuous monitoring in complex matrices are needed. In this work, sensors, based on polyelectrolyte layer-by-layer (LbL) films prepared onto gold interdigitated electrodes (IDE), were studied. An electronic tongue array, composed of (polyethyleneimine (PEI)/polysodium 4-styrenesulfonate (PSS))₅ and (poly(allylamine hydrochloride/graphene oxide)₅ LbL films together with gold IDE without coating were used to detect TCS concentrations (10⁻¹⁵–10⁻⁵ M). Electrical impedance spectroscopy was used as means of transduction and the obtained data was analyzed by principal component analysis (PCA). The electronic tongue was tested in deionized water, mineral water and wastewater matrices showing its ability to (1) distinguish between TCS doped and non-doped solutions and (2) sort out the TCS range of concentrations. Regarding film stability, strong polyelectrolytes, as (PEI/PSS)_n, presented more firmness and no significant desorption when immersed in wastewater. Finally, the PCA data of gold IDE and (PEI/PSS)₅ sensors, for the mineral water and wastewater matrices, respectively, showed the ability to distinguish both matrices. A sensitivity value of 0.19 ± 0.02 per decade to TCS concentration and a resolution of 0.13 pM were found through the PCA second principal component.

Removal of organic micropollutants from biologically treated greywater using continuous-flow vacuum-UV/UVC photo-reactor

Despite growing apprehension regarding the fate of organic micropollutants (MPs) of emerging concern, little attention has been paid to their presence in domestic greywater, where they mainly originate from personal care products. Many MPs are not fully removed in conventional greywater treatments and require additional treatment. Vacuum-UV radiation (VUV) can generate ·OH in situ, via water photolysis, initiating advanced oxidation process (AOP) without any chemical addition. Despite growing interest in VUV-based AOP, its performance in real-life grey- or wastewater matrices has hardly been investigated. The present study investigates the removal of triclosan (TCS) and oxybenzone (BP3), common antibacterial and UV-filter MPs, in deionized water (DIW) and in treated greywater (TGW) using combined UVC/VUV or UVC only radiation in a continuous-flow reactor. Degradation kinetics of these MPs and their transformation products (TPs) were addressed, as well as bacterial growth inhibition of the resulting reactor's effluent. In DIW, MP degradation was much faster under the combined UVC/VUV irradiation. In TGW, the combined radiation successfully removed both MPs but at lower efficiency than in DIW, as particles and dissolved organic matter (DOM) acted as radical scavengers. Filtration and partial DOM removal prior to irradiation improved the process efficiency and reduced energy requirements under the combined radiation (from 1.6 and 167 to 1.1 and 6.0 kWh m^-3·^ּorder^-1 for TCS and BP3, respectively). VUV radiation also reduced TP concentrations in the effluent. As a result, bacterial growth inhibition of triclosan solution irradiated by VUC/VUV was lower than that irradiated by UVC light alone, for UV dose > 120 mJ cm^-2.

Occurrence of the Persistent Antimicrobial Triclosan in Microwave Pretreated and Anaerobically Digested Municipal Sludges under Various Process Conditions

Treatment of emerging contaminants, such as antimicrobials, has become a priority topic for environmental protection. As a persistent, toxic, and bioaccumulative antimicrobial, the accumulation of triclosan (TCS) in wastewater sludge is creating a potential risk to human and ecosystem health via the agricultural use of biosolids. The impact of microwave (MW) pretreatment on TCS levels in municipal sludge is unknown. This study, for the first time, evaluated how MW pretreatment (80 and 160 °C) itself and together with anaerobic digestion (AD) under various sludge retention times (SRTs: 20, 12, and 6 days) and temperatures (35 and 55 °C) can affect the levels of TCS in municipal sludge. TCS and its potential transformation products were analyzed with ultra-high-performance liquid chromatography and tandem mass spectrometry. Significantly higher TCS concentrations were detected in sludge sampled from the plant in colder compared to those in warmer temperatures. MW temperature did not have a discernible impact on TCS reduction from undigested sludge. However, AD studies indicated that compared to controls (no pretreatment), MW irradiation could make TCS more amenable to biodegradation (up to 46%), especially at the elevated pretreatment and digester temperatures. At different SRTs studied, TCS levels in the thermophilic digesters were considerably lower than that of in the mesophilic digesters.

Immobilization of laccase onto meso-MIL-53(Al) via physical adsorption for the catalytic conversion of triclosan

Due to the abundant binding sites and high stability, a synthesized meso-MIL-53(Al) was selected as the backbone and used for immobilizing laccase (Lac-MIL-53(Al)) to catalytically degrade of TCS. XRD, BET and FTIR analyses proved that the carboxyl groups on PTA of meso-MIL-53(Al) could provide sufficient adsorption sites for physically immobilizing laccase through hydrogen bonds and electrostatic interactions. Although the catalytic efficiency of V_max/K_m slightly decreased from 785 to 607 min^-1 due to the mass transfer limitation upon immobilized, Lac-MIL-53(Al) showed high activity recovery (93.8%) and stability. The conformational analysis indicated the laccase could partially enter into the MOF by conformational changes without impairing laccase, although the laccase molecular (6.5 nm × 5.5 nm × 4.5 nm) was larger than the mesopore sizes of the MOF (4 nm). The kinetics indicated that Lac-MIL-53(Al) could remove 99.24% of TCS within 120 min due to the synergy effect of the adsorption of meso-MIL-53(Al) and catalytic degradation of laccase. Meanwhile, Lac-MIL-53(Al) could remain approximately 60% of activity for up to 8 times reuse without desorption. The GC/MS and LC/MS/MS analyses further confirmed that TCS could be transformed to 2, 4-DCP by laccase via the breakage of the ether bond, or to passivated dimers, trimers and tetramers by the self-coupling and oxidization of the phenoxyl radicals, and finally removed by precipitation. In summary, enzyme-MOF composite might be a potential strategy to control the micropollutants in the wastewater.

Does salinity modulates the response of Mytilus galloprovincialis exposed to triclosan and diclofenac?

In the present study Mytilus galloprovincialis mussels were exposed for 28 days to three salinities: 30 (control), 25 and 35. Simultaneously, organisms at each salinity were exposed to either the antimicrobial agent Triclosan (TCS) or the pharmaceutical drug Diclofenac (DIC) at 1 μg/L. Salinity alone and exposure to PPCPs changed mussel's metabolic capacity and oxidative status, but no additive or synergetic effects resulting from the combined exposures were observed. Overall, the metabolic capacity of mussels was decreased when exposed to TCS and DIC under control salinity, which was less pronounced at salinities out of the control level. TCS had a notorious effect over glutathione peroxidase activity while DIC exposure enhanced catalase response. Such defence mechanisms were able to prevent cellular damage but still a clear reduction in GSH/GSSG ratio after PPCPs exposures indicates oxidative stress which could compromise bivalve's performance to further stressing events.

Human urine contamination with environmental pollutants: simultaneous determination using UPLC-MS/MS

Paraben derivatives are widely used as an antifungal, antimicrobial preservative in cosmetic products, pharmaceuticals, and food. These molecules are called endocrine disruptors (EDCs). The exposure of the human body to paraben derivatives needs further study and for this purpose 200 urine samples were collected from Tunisian men and women aged between 5 and 90 years to determine three paraben derivatives: methylparaben (MP), ethylparaben (EP) and propylparaben (PP) using ultra performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS). The three major parabens were found in 95 urine samples. The obtained results indicate that MP, EP, and PP were detected in 57%, 46%, and 40% of all samples, respectively. Urinary concentration for the three parabens was in the range of 0.88-84.46 ng/mL, 0.52-29.2 ng/mL, and 0.51-28.17 ng/mL of PP, MP, and EP, respectively. In addition, the concentrations of the paraben derivatives in women were higher than those of men. These findings indicate that the exposure occurs from common products (foods, cosmetics, and pharmaceuticals). The Tunisian authorities should control the composition of packaging of these common products in order to protect humans against EDCs.

The influence of temperature on the effects induced by Triclosan and Diclofenac in mussels

Little is known about the consequences of exposure to pharmaceuticals and personal care products (PPCPs) in elevated temperatures associated with climate change. To increase the knowledge on this topic, Mytilus galloprovincialis mussels were exposed to 1.0 μg/L of either the antimicrobial Triclosan (TCS) or the anti-inflammatory drug Diclofenac (DIC), at control (17 °C) and 4 °C raised (21 °C) temperatures for 28 days. Triclosan and DIC concentrations in the water and tissues were subsequently measured and related to biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen and protein reserves), oxidative stress markers, glutathione balance between the reduced and the oxidised form (GSH/GSSG), and damage to proteins and lipids. Mussels responded to the increase in temperature and drug exposure by lowering their metabolic rate (decreased ETS), increasing their endogenous reserves and antioxidant defences, thus preventing oxidative stress damage, with the exception of DIC exposure at the higher temperature. In all cases, GSH/GSSG ratio was reduced in detriment of the antioxidant form at both PPCPs exposures and elevated temperature with no additive effect due to combined stressors. Overall, either drug exposure or increased temperature could compromise the ability of mussels to withstand further insults.

Sonochemical degradation of triclosan in water in a multifrequency reactor

Degradation of triclosan (TCS) by multifrequency ultrasound (US) was studied at high and low frequencies. Frequency effect on initial degradation rates was analyzed, and an optimum frequency was found. Power density always has a positive effect on degradation rates over the whole equipment work range. A reaction mechanism similar to that proposed by Serpone resulted in a pseudo-linear model that fitted statistically better than the nonlinear model proposed by Okitsu. Pulsed US showed a positive effect on degradation rates; however, simultaneous analysis of the effect of power, frequency, pulse time, and silent time did not show a clear trend for degradation as a function of pulse US variables. According to these results and those for degradation in the presence of radical scavengers, it was concluded that US TCS degradation was taking place in the bubble/liquid interface. A toxicity test was conducted by Microtox®, showing a decrease in toxicity as TCS concentration decreased and increase in toxicity after total depletion of TCS. Eight possible degradation by-products were identified by GC-MS analysis, and a degradation pathway was proposed.

Profiling of small molecule metabolites and neurotransmitters in crustacean hemolymph and neuronal tissues using reversed-phase LC-MS/MS

Crustaceans have been long used as model animals for neuromodulation studies because of their well-defined neural circuitry. The identification of small molecule metabolites and signaling molecules in circulating fluids and neuronal tissues presents unique challenges due to their diverse structures, biological functions, and wide range of concentrations. LC combined with high resolution MS/MS is one of the most powerful tools to uncover endogenous small molecules. Here we explored several sample preparation techniques (solid-phase extraction and denaturing) and MS data acquisition strategies (data-dependent acquisition and targeted MS2-based acquisition) that provided complementary coverage and improved overall identification rate in C18 LC-MS/MS experiment. By MS/MS spectral matching with mzCloud database and those generated from standard compounds, a total of 129 small molecule metabolites and neurotransmitters were identified from crustacean hemolymph and neuronal tissues. These confidently identified small molecules covered predominant biosynthetic pathways for major neurotransmitters, validating the effectiveness of the high-throughput RPLC-MS/MS approach in studying the metabolism of neurotransmitters.

Effect of triclosan and its photolysis products on marine bacterium V. fischeri and freshwater alga R. subcapitata

The use of antibacterial agents in consumer products may lead to adverse effects in waters receiving treated wastewater. Triclosan is one of the antibacterial agents used widely in the world and its high usage leads to relatively high concentrations in wastewater effluents. In this study, the probable effect of triclosan in receiving waters was assessed using different organisms. The EC50 values were 668 ± 80 μg/L and 7.8 ± 0.1 μg/L, for Vibrio fischeri and Raphidocelis subcapitata, respectively, indicating the higher sensitivity of the alga. The toxicity of triclosan upon exposure to UV light decreased for both species, as suggested by the increase in EC50 values (1300 ± 50 μg/L and 8.7 ± 0.6 μg/L for V. fischeri and R. subcapitata, respectively). The effect of photolysis on toxicity reduction was higher for V. fischeri and the EC50 values were similar for direct and indirect photolysis. LC-MS/MS analysis of samples with and without UV exposure suggested a decrease in triclosan concentration as well as formation of photolysis byproducts upon photolysis.

Vortex assisted-supramolecular solvent based microextraction coupled with spectrophotometric determination of triclosan in environmental water samples

A simple, fast and environmental friendly vortex assisted-supramolecular solvent based microextraction (VA-SSME) method was developed for the preconcetration of triclosan in wastewater prior to UV spectrophotometric determination. To achieve maximum sensitivity and accuracy for the target analyte, the experimental parameters affecting the VA-SSME procedure were optimized using response surface methodology (RSM). Under optimised conditions, the correlation coefficient (R2) and recoveries were 0.9994 and 100.31-118.5%, respectively. The intra-day (repeatability) and inter-day (reproducibility) precisions expressed in terms of relative standard deviation (RSD) were 2-4% and 5.2%, respectively. The preconcentration factor and limits of detection (LOD) and quantification (LOQ) were found to be 90, 0.28 μg L−1 and 0.92 μg L−1, respectively. The developed VA-SSME/UV method was applied for the determination of triclosan in real samples collected over a period of three months. The analytical results obtained showed that triclosan was frequently detected in influent wastewater samples but was not detected in effluent samples.

High efficiency removal of triclosan by structure-directing agent modified mesoporous MIL-53(Al)

In order to expand the potential applications of metal-organic frameworks (MOFs), structure directing agents modified mesoporous MIL-53(Al) (MIL-53(Al)-1) was investigated to adsorb triclosan (TCS) with two different initial concentrations. MIL-53(Al)-1 with high mesoporosity and total pore volume exhibited higher adsorption capacity and 4.4 times faster adsorption of TCS at low concentration (1 mg L^-1) than that of microporous MIL-53(Al). Also, mesoporous as well as microporous MIL-53(Al) showed significant higher adsorption capacity and two orders of magnitude greater fast uptake of TCS than two kinds of mesoporous-activated carbon. The adsorption of TCS onto MIL-53(Al)-1 released more energy and had higher disorderliness than TCS on MIL-53(Al). The superior adsorption characteristics of MIL-53(Al)-1 were preserved over a wide pH range (4-9), at high concentration of ionic strengths, and in the presence of coexisting compounds (anions, cations, phenol, aniline, and humic acid). The selectivity adsorption and Fourier transform infrared (FT-IR) spectra revealed that TCS adsorption on MIL-53(Al)s was mainly driven by hydrophobicity interaction assisted with hydrogen bonding on MIL-53(Al)s. MIL-53(Al)s can be effectively regenerated several times by washing with 90% methanol-water (pH 11). All of the above results demonstrated MIL-53(Al)s are promising adsorbents for water purification. Graphical abstract.

Fate and mass balance of triclosan and its degradation products: Comparison of three different types of wastewater treatments and aerobic/anaerobic sludge digestion

Triclosan (TCS) as an antimicrobial agent has been ubiquitously found in wastewater and sewage sludge. TCS may undergo transformation/degradation during wastewater treatment. Some of the resulted products such as 2,4-dichlorophenol (2,4-DCP), 2,8-dichlorodibenzoparadioxin (2,8-DCDD) and methyl triclosan (MTCS) are presumed toxic/persistent compounds. In this study, fate of TCS and the probability of formation of important degradation products were investigated in three susceptible wastewater/sludge treatment practices. 24.1% and 27.2% of the loading TCS was adsorbed to the generated sludge, whereas up to 60% of the loading TCS was biotransformed. Up to 9.9% and 13.0% of TCS loss was attributed to the formation of 2,4-DCP and 2,8-DCDD in chlorination and UV disinfection, respectively. Anaerobic and aerobic sludge digestion processes eliminated up to 23.0% and 56.0% of TCS, respectively. About 7.4% of TCS in aerobic digestion was transformed to methyl triclosan (MTCS). Significant temporal variation of TCS was observed in primary sedimentations, except for chemically enhanced primary treatment that was suggested to be governed by chemical-forced sedimentation. Distribution coefficient (K_d) of TCS was directly correlated to the total organic carbon of the sludge (TOC). Moreover, strong correlation was observed between elimination efficiency in primary sedimentation and loading concentration.

Procedures of determining organic trace compounds in municipal sewage sludge-a review

Sewage sludge is the largest by-product generated during the wastewater treatment process. Since large amounts of sludge are being produced, different ways of disposal have been introduced. One tempting option is to use it as fertilizer in agricultural fields due to its high contents of inorganic nutrients. This, however, can be limited by the amount of trace contaminants in the sewage sludge, containing a variety of microbiological pollutants and pathogens but also inorganic and organic contaminants. The bioavailability and the effects of trace contaminants on the microorganisms of soil are still largely unknown as well as their mixture effects. Therefore, there is a need to analyze the sludge to test its suitability before further use. In this article, a variety of sampling, pretreatment, extraction, and analysis methods have been reviewed. Additionally, different organic trace compounds often found in the sewage sludge and their methods of analysis have been compiled. In addition to traditional Soxhlet extraction, the most common extraction methods of organic contaminants in sludge include ultrasonic extraction (USE), supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), and pressurized liquid extraction (PLE) followed by instrumental analysis based on gas or liquid chromatography and mass spectrometry.

A Study of 2,3,7,8-Tetrachlorodibenzo-p-dioxin Induced Liver Injury in Jian Carp (Cyprinus carpio var. Jian) Using Precision-Cut Liver Slices

The aim of this study was to establish a model for the study of liver injury induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Jian carp using precision-cut liver slices (PCLS). PCLS were treated with TCDD at concentrations of 0, 0.05, 0.1, 0.3, and 0.6 μg/L for 6 h, followed by collection of the culture supernatant and PCLS for analysis. Several biochemical indices were analyzed, including glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), lactate dehydrogenase (LDH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA). Expression of mRNA was also estimated for cytochrome P4501A (CYP1A), aryl hydrocarbon receptor2 (AhR2), and aryl hydrocarbon receptor nuclear translocator2 (ARNT2). Results showed that some significant effects (p < 0.05) in MDA, GSH-Px and PCLS viability were observed at a TCDD concentration as low as 0.05 µg/L, and the observed effects increased with exposure concentration. Following exposure to TCDD for 6 h at a concentration of 0.3 μg/L, significant increases (p < 0.01) in the content of GPT, GOT, MDA, and LDH were observed, while SOD activity, GSH-Px activity, and PCLS viability were decreased (p < 0.01 or p < 0.05). Exposure to 0.3 μg/L TCDD also resulted in increased expression of mRNA for CYP1A, AhR2, and ARNT2. Overall, these results provide evidence of TCDD-induced liver injury and oxidative stress in Jian carp. These results also support the use of PCLS as an in vitro model for the evaluation of hepatotoxicity in Jian carp.