A Unique Monitoring Method for Fecal and Sewage-Derived Chemical Pollution Utilizing International Pellet Watch Approach.

This study established a unique approach to assess fecal contamination by measuring fecal sterols, especially coprostanol (5ß-cholestanol-3ß-ol, 5ß) and cholestanol (5α-cholestan-3ß-ol, 5α) and their ratio 5ß/(5ß + 5α) alongside triclosan (TCS) and methyl-triclosan (MTC) in beached plastic pellets across 40 countries. Coprostanol concentrations ranged from 3.6 to 8190 ng/g pellet with extremely high levels in densely populated areas in African countries. The 5ß/(5ß + 5α) ratio was not affected by the difference in residence time of pellets in aquatic environments, and their spatial pattern showed a positive correlation with that of sedimentary sterols, demonstrating its reliability as an indicator of fecal contamination. Pellets from populated areas of economically developing countries, i.e., Africa and Asia, with lower coverage of wastewater treatment exhibited higher 5ß/(5ß + 5α) ratios (∼0.7) corresponding to ∼1% sewage in seawater, while pellets from developed countries, i.e., the USA, Canada, Japan, and Europe, with higher coverage of modern wastewater treatment displayed lower ratios (∼0.5), corresponding to the first contact limit. Triclosan levels were higher in developing countries (0.4-1298 ng/g pellet), whereas developed countries showed higher methyl-triclosan levels (0.5-70 ng/g pellet) due to TCS conversion during secondary treatment. However, some samples from Japan and Europe displayed higher TCS levels, suggesting contributions from combined sewage overflow (CSO). Combination of 5ß/(5ß + 5α) and MTC/TCS ratios revealed extreme fecal contamination from direct input of raw sewage due to inadequate treatment facilities in some African and South and Southeast Asian countries.

Competitive and cooperative sorption between triclosan and methyl triclosan on microplastics and soil.

The sorption behavior of single contaminant on microplastics (MPs) has been extensively studied; however, little is known about that in the more actual scenario containing multiple contaminants. In this study, the interaction between triclosan (TCS) and its primary metabolite, methyl triclosan (MTCS) on polyethylene (PE), polystyrene (PS), and soil was investigated. Results indicate that the more hydrophobic MTCS had much higher sorption capacity and affinity than TCS. Competitive sorption between them occurred in most cases and appeared to be concentration-dependent (in the range of 0.1-5 mg TCS/L and 0.01-≤0.05 mg MTCS/L of primary solutes, respectively): more pronounced at low concentrations of primary solute, while progressively weaker with the increase of concentrations. Among the sorbents, MTCS exhibited strong antagonistic effect on TCS sorption for MPs, especially PS, while significant suppression of MTCS sorption by TCS took place for soil and PS rather than PE. Additionally, it is interesting to observe that the presence of TCS substantially facilitated the sorption of MTCS exclusively at high concentrations on both PS and soil, presumably attributed to the solute-multilayer formation. Furthermore, the magnitude of the two effects varied with solution pH: TCS sorption at alkaline pH was the most suppressed by MTCS because the less hydrophobic dissociated TCS tended to be displaced, and the highest cooperative sorption of MTCS with TCS occurred at acidic pH because neutral TCS preferentially adsorbed on sorbent surface could provide additional sorption sites for MTCS. Both competitive and cooperative effects between multiple contaminants may affect their fate and transport, thereby these findings are helpful for assessing the environmental risk of MPs and TCS in soil.

Association of urinary triclosan, methyl triclosan, triclocarban, and 2,4-dichlorophenol levels with anthropometric and demographic parameters in children and adolescents in 2020 (case study: Kerman, Iran).

Endocrine-disrupting chemicals (EDCs) can be a major risk factor for noncommunicable illnesses, especially when children are exposed to them. The purpose of this study was to assess the urine concentrations of triclosan (TCS), methyl triclosan (MTCS), triclocarban (TCC), and 2,4-dichlorophenol (2,4-DCP) and its association with anthropometric and demographic parameters in children and adolescents aged 6-18 living in Kerman, Iran, in 2020. A GC/MS instrument was used to measure the concentrations of the analytes. TCS, MTCS, TCC, and 2,4-DCP geometric mean concentrations (µg/L) were 4.32 ± 2.08, 1.73 ± 0.88, 4.66 ± 10.25, and 0.19 ± 0.14, respectively. TCS, MTCS, TCC, and 2,4-DCP were shown to have a positive and significant association with BMI z-score and BMI (p-value < 0.01). TCS and MTCS have a positive, strong, and substantial association (p-value < 0.01, r = 0.74). There was no significant association between the waist circumference (WC) and the analytes studied. In addition, there was a close association between analyte concentration and demographic parameters (smoking, education, income, etc.) overall. In Kerman, Iran, the current study was the first to look into the association between TCS, MTCS, TCC, and 2,4-DCP analytes and anthropometric and demographic data. The levels of urinary TCS, MTCS, TCC, 2,4-DCP, and anthropometric parameters in children and adolescents are shown to have a significant association in this study. However, because the current study is cross-sectional and it is uncertain if a single experiment accurately reflects long-term exposure to these analytes, more research is needed to determine the impact of these analyses on the health of children and adolescents.

A solid-phase microextraction fiber coating based on magnetic covalent organic framework for highly efficient extraction of triclosan and methyltriclosan in environmental water and human urine samples.

Herein, we synthesized a kind of magnetic covalent organic framework nanohybrids (NiFe2O4@COF), and integrated it with polydimethyl siloxane and silicone rubber curing agent for solid phase microextraction (SPME) fiber coating. The fiber coating demonstrated a porous and uniform surface with the BET specific surface of 169.7 m2 g-1. As for seven environmental analytes, the NiFe2O4@COF-based SPME fiber coating gave the higher extraction recoveries for triclosan (TCS) and methyltriclosn (MTCS) than those of fenpropathrin, bifenthrin, permethrin, fenvalerate and deltamethrin. Several operational parameters were rigorously optimized, such as extraction temperature, extraction time, thermal desorption time, solution pH and salt effect. Combined with the GC-ECD detection, the newly developed microextraction method supplied the wide linear range of 0.1-1000 µg L-1 with the correlation coefficients of > 0.9995. The limits of detection (LODs) and limits of quantitation (LOQs) reached as low as 1-7 ng L-1 and 3.3-23 ng L-1, respectively. The intra-day and inter-day precisions in six replicates (n = 6 ) were < 3.55% and < 5.06%, respectively, and the fiber-to-fiber reproducibility (n = 3) was < 7.64%. To evaluate its feasibility in real samples, the fortified recoveries for TCS and MTCS, at low (0.2 µg L-1), middle (2.0 µg L-1) and high (20.0 µg L-1) levels, varied between 81.9% and 119.1% in tap, river and barreled waters as well as male, female and children urine samples. Especially, it is worth mentioning that the NiFe2O4@COF-based SPME coating fiber can be recycled for at least 150 times with nearly unchanged extraction efficiency. Moreover, the extraction recoveries by the as-fabricated fiber coating were much higher than those by three commercial fibers (PDMS, PDMS/DVB and PDMS/DVB/CAR). Overall, the NiFe2O4@COF-based SPME is a convenient, sensitive, efficient and "green" pretreatment method, thereby possessing important application prospects in trace monitoring of TCS-like pollutants in complex liquid matrices.

Ecotoxicogenomic analysis of zebrafish embryos exposed to triclosan and mixture triclosan and methyl triclosan using suppression subtractive hybridization and next-generation sequencing.

Triclosan (TCS) and methyl-triclosan (MTCS), an environmental transformation product of biocide of TCS, have been detected in water, sediment, fish, and invertebrates. In this study, the key pathway perturbation in zebrafish (Danio rerio) embryos exposed to TCS (300 µg/L) and TCS/MTCS mixture (300 µg/L TCS + 30 µg/L MTCS) was assessed by integrating the metabolomic and transcriptomic dysregulation. The differential expressed genes (DEGs) were obtained from the subtracted cDNA libraries by using the suppression subtractive hybridization and next-generation sequencing approach. The dysregulation of twenty-eight GO terms and four KEGG pathways, including oxidative phosphorylation and cardiac muscle contraction, were shown in the TCS treatment group, indicating that TCS could disrupt the mitochondrial inner membrane function by downshifting the electrochemical gradient. Meanwhile, the addition of MTCS in the exposure would cause fourteen additional significant KEGG pathway changes, demonstrating the different effects between two exposure. A pathway-based analysis using the identified DEGs and the altered metabolites in zebrafish embryos treated with TCS and TCS/MTCS mixture, collectively, has been applied. This study demonstrated that the integration of SSH-NGS and metabolomics could reveal toxic effects and potential diseases associated with the exposures of TCS and MTCS in aquatic environments.

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 (91.1-589 µg/kg) in fish was higher than that of TCC (29.1-285.5 µg/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.

Organic Micropollutants in Wastewater Effluents and the Receiving Coastal Waters, Sediments, and Biota of Lyttelton Harbour (Te Whakaraupo), New Zealand.

Coastal ecosystems are receiving environments for micropollutants due to high levels of associated anthropogenic activities. Effluent discharges from wastewater treatment plants are a significant source of micropollutants to coastal environments. Wastewater effluents, seawater, sediments, and green-lipped mussels (Perna canaliculus) in Lyttelton Harbour (Te Whakaraupo), Christchurch, New Zealand, were analysed for a suite of personal care products and steroid hormones during a 1-year period. In wastewater effluents, the concentration of methyl paraben (mParaben), ethyl paraben (eParaben), propyl paraben (pParaben), butyl paraben (bParaben), 4-t-octylphenol (OP), 4-methylbenzylidene camphor (4-MBC), benzophenone-3 (BP-3), benzophenone-1 (BP-1), triclosan, methyl triclosan (mTric), Bisphenol A (BPA), Estrone (E1), 17ß-estradiol (E2), 17α-ethinyl estradiol (EE2), and Estriol (E3) ranged from < 0.6 to 429 ng L-1 and was dominated by OP, 4-MBC, BP-3, triclosan, BP-1, and BPA. In seawater, 4-MBC, BP-3, BPA, and E1 were the most frequently detected contaminants (< 0.2-9.4 ng L-1). Coastal sediment samples contained mParaben, OP, 4-MBC, BP-3, BP-1, BPA, OMC, and E1 (< 0.2-11 ng g-1 d.w.), and mParaben, OP, and BP-3 were found to bioaccumulate (3.8-21.3 ng g-1 d.w.) in green lipped mussels.

In Vitro Antimycobacterial Activity and Physicochemical Characterization of Diaryl Ether Triclosan Analogues as Potential InhA Reductase Inhibitors.

Two sets of diphenyl ether derivatives incorporating five-membered 1,3,4-oxadiazoles, and their open-chain aryl hydrazone analogs were synthesized in good yields. Most of the synthesized compounds showed promising in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv. Three diphenyl ether derivatives, namely hydrazide 3, oxadiazole 4 and naphthylarylidene 8g exhibited pronounced activity with minimum inhibitory concentrations (MICs) of 0.61, 0.86 and 0.99 µg/mL, respectively compared to triclosan (10 µg/mL) and isoniazid (INH) (0.2 µg/mL). Compounds 3, 4, and 8g showed the InhA reductase enzyme inhibition with higher IC50 values (3.28-4.23 µM) in comparison to triclosan (1.10 µM). Correlation between calculated physicochemical parameters and biological activity has been discussed which justifies a strong correlation with respect to the inhibition of InhA reductase enzyme. Molecular modeling and drug-likeness studies showed good agreement with the obtained biological evaluation. The structural and experimental information concerning these three InhA inhibitors will likely contribute to the lead optimization of new antibiotics for M. tuberculosis.

Emerging organic contaminants in wastewater: Understanding electrochemical reactors for triclosan and its by-products degradation.

Degradation technologies applied to emerging organic contaminants from human activities are one of the major water challenges in the contamination legacy. Triclosan is an emerging contaminant, commonly used as antibacterial agent in personal care products. Triclosan is stable, lipophilic and it is proved to have ecotoxicologic effects in organics. This induces great concern since its elimination in wastewater treatment plants is not efficient and its by-products (e.g. methyl-triclosan, 2,4-dichlorophenol or 2,4,6-trichlorophenol) are even more hazardous to several environmental compartments. This work provides understanding of two different electrochemical reactors for the degradation of triclosan and its derivative by-products in effluent. A batch reactor and a flow reactor (mimicking a secondary settling tank in a wastewater treatment plant) were tested with two different working anodes: Ti/MMO and Nb/BDD. The degradation efficiency and kinetics were evaluated to find the best combination of current density, electrodes and set-up design. For both reactors the best electrode combination was achieved with Ti/MMO as anode. The batch reactor at 7 mA/cm2 during 4 h attained degradation rates below the detection limit for triclosan and 2,4,6-trichlorophenol and, 94% and 43% for 2,4-dichlorophenol and methyl triclosan, respectively. The flow reactor obtained, in approximately 1 h, degradation efficiencies between 41% and 87% for the four contaminants. This study suggests an alternative technology for emerging organic contaminants degradation, since the combination of a low current density with the flow and matrix induced disturbance increases and speeds up the compounds' elimination in a real environmental matrix.

Synthesis, evaluation, molecular docking, and molecular dynamics studies of novel N-(4-[pyridin-2-yloxy]benzyl)arylamine derivatives as potential antitubercular agents.

A new series of novel triclosan (2,4,4'-trichloro-2'-hydroxydiphenylether) analogues were designed, synthesized, and screened for their in vitro antimycobacterial and antibacterial activities. Most of the compounds showed significant activity against Mycobacterium tuberculosis H37Rv strain with minimum inhibitory concentration (MIC) values in 20-40 µM range in GAST/Fe medium when compared with triclosan (43 µM) in the first week of assay, and after additional incubation, seven compounds, that is, 2a, 2c, 2g, 2h, 2i, 2j, and 2m, exhibited MIC values at the concentration of 20-40 µM. The compounds also showed more significant activity against Bacillus subtilis and Staphylococcus aureus. The synthesized compounds showed druggable properties, and the predicted ADME (absorption, distribution, metabolism, and excretion) properties were within the acceptable limits. The in silico studies predicted better interactions of compounds with target protein residues and a higher dock score in comparison with triclosan. Molecular dynamics simulation study of the most active compound 2i was performed in order to further explore the stability of the protein-ligand complex and the protein-ligand interaction in detail.

The toxic effect of triclosan and methyl-triclosan on biological pathways revealed by metabolomics and gene expression in zebrafish embryos.

The omnipresence of antimicrobial triclosan (TCS) and by-products in aquatic environments is a threat to aquatic organisms. Traditionally, the adverse effects of TCS and its by-products have been evaluated by examining the phenotypic output relevant to predicting acute toxicity rather than studying the perturbation of biological pathways. Identifying alterations in the key pathways and molecular mechanisms caused by toxic chemicals helps researchers assess the ecological risks of TCS and its by-products to aquatic environments. In this study, we used metabolomics and reverse transcription qPCR to investigate the adverse effects of a wide range of concentrations of triclosan and its derivative methyl-triclosan (MTCS), ranging from relatively low environmentally relevant levels (ng/L) to high-dose concentrations (sublethal concentration), on zebrafish (Danio rerio) embryos. The metabolism and transcriptome analysis revealed changes in the metabolite and transcripts expression of zebrafish embryos after 96 h exposure at 30 µg/L and 300 µg/L of TCS, 400 µg/L of MTCS and the TCS/MTCS mixture (30 µg/L TCS + 3 µg/L MTCS and 300 µg/L TCS + 30 µg/L MTCS). Significant dysregulations in the expression of the urea transporter (UT), glucose-6-phosphate dehydrogenase (G6PD), alanine transaminase (ALT), glutamate dehydrogenase (GDH), phosphoglucomutase (PGM), and fatty acid synthase (FASN), together with changes in alanine, urea, glucose, 6-phosphogluconalactone, and palmitic acid were observed in the TCS, MTCS, and TCS/MTCS treatments. Particularly, the MTCS treatment group showed fold changes in the mRNA expression of nitrogen metabolism, energy metabolism, and fatty acid synthesis, indicating a disruption of the zebrafish embryos' biological pathways. The changes in the metabolites and gene expressions induced by the TCS, MTCS and the TCS/MTCS mixture treatment demonstrate the pathway changes in starch and sucrose metabolism, nitrogen metabolism, fatty acid synthesis, and phenylalanine, tyrosine and tryptophan biosynthesis. Therefore, our study provides better insights into the risks of the parental compound (TCS) and its by-product (MTCS), as well as the perturbation in biological pathways induced by these two compounds in aquatic environments.

Ligand- and Structure-Based Approaches of Escherichia coli FabI Inhibition by Triclosan Derivatives: From Chemical Similarity to Protein Dynamics Influence.

Enoyl-acyl carrier protein reductase (FabI) is the limiting step to complete the elongation cycle in type II fatty acid synthase (FAS) systems and is a relevant target for antibacterial drugs. E. coli FabI has been employed as a model to develop new inhibitors against FAS, especially triclosan and diphenyl ether derivatives. Chemical similarity models (CSM) were used to understand which features were relevant for FabI inhibition. Exhaustive screening of different CSM parameter combinations featured chemical groups, such as the hydroxy group, as relevant to distinguish between active/decoy compounds. Those chemical features can interact with the catalytic Tyr156. Further molecular dynamics simulation of FabI revealed the ionization state as a relevant for ligand stability. Also, our models point the balance between potency and the occupancy of the hydrophobic pocket. This work discusses the strengths and weak points of each technique, highlighting the importance of complementarity among approaches to elucidate EcFabI inhibitor's binding mode and offers insights for future drug discovery.

The methyl-triclosan induced caspase-dependent mitochondrial apoptosis in HepG2 cells mediated through oxidative stress.

Methyl-triclosan (MTCS) is a dominant transformation product of triclosan (TCS), which has been widely used as an effective antimicrobial ingredient with increasing concentrations in the environment. MTCS shows higher persistence in environment than its parent chemical TCS. The toxic effects of MTCS and toxicological mechanism are not well understood up to now. This study investigated the cytotoxic effects of MTCS in HepG2 cells in terms of cell viability, apoptosis induction, ROS production, GSH/GSSG levels, Mitochondrial Membrane Potential (MMP) reduction, LDH release, glucose uptake and ATP production. Moreover, the related gene transcripts were measured with RT-qPCR assay. Cytotoxic experiments in HepG2 cells revealed that MTCS exposure at micromol per liter levels had toxic effects as evidenced by decreased cell survival, elevated cell apoptosis, reduced MMP and increased LDH release. These toxic effects were associated with increased ROS production and reduced GSH/GSSG ratio. Meanwhile, elevated glucose uptake and ATP production indicated that MTCS induced membrane damages resulted not from a typical mitochondrial uncoupler, but from oxidative stress. Analysis of gene transcripts showed that MTCS exposure induced mRNA expressions alterations associated with oxidative stress response, energy production, cell cycle regulation and cell apoptosis. In general, the caspase-dependent mitochondrial apoptosis pathway might play a role in MTCS induced cytotoxicity in HepG2 cells.

Assessment of the effect of methyl-triclosan and its mixture with triclosan on developing zebrafish (Danio rerio) embryos using mass spectrometry-based metabolomics.

Methyl-triclosan (MTCS), as a biodegradation product from antibacterial triclosan (TCS), has been detected in water catchments, and it has also been verified to accumulate in biota due to its hydrophobicity. There is a lack, however, of toxicity studies on MTCS and its effects on organisms in conjunction with TCS. In this study, exposure experiments were conducted to assess the toxicity to embryonic zebrafish of selected concentrations of MTCS (from 1 ng/L to 400 µg/L) and MTCS/TCS mixtures (from 1 µg/L TCS and 100 ng/L MTCS to 300 µg/L TCS and 30 µg/L MTCS). Specimens were extracted using acetonitrile: isopropanol: water (3:3:2; v/v/v) and then analyzed using Gas chromatography-mass spectrometry (GC-MS) to identify the metabolites based on the Fiehn library database. The results showed that MTCS exposure led to the alterations of the metabolomes of the zebrafish embryos, including level changes of l-valine, d-mannose, d-glucose, and other metabolites. Multivariate analysis (PCA, PLS-DA, sPLS-DA) and univariate analysis (one-way ANOVA) indicated differences between the control and exposure groups of the metabolites, indicating that biological pathways, such as amino acid synthesis, pentose phosphate pathway (PPP), starch and sucrose metabolism were influenced. Moreover, when the embryos were exposed to a mix of TCS and MTCS, TCS dominated the mixture's effect on biological pathways because the concentration ratio within the mixture, which mimics environmental ratio of 10 TCS : 1 MTCS, leads to high bioavailability of TCS.

Synthesis and antibacterial profiles of targeted triclosan derivatives.

There is an ongoing urgent need for new targeted antibacterial compounds with novel mechanisms of action for the treatment of infections caused by bacteria that are resistant to currently available materials. Since the expression of glycosidase enzymes within bacteria is unequally distributed, glycoside derivatives of antibacterial agents offer potential as targeted prodrugs for bacterial infections. Herein we report the synthesis and characterisation of four α-D-glycopyranosides and three ß-D-glycopyranosides of the broad antibacterial agent triclosan, in generally good synthetic yields, and with excellent purities. Each glycoside was analysed to determine its ability to inhibit the growth of a wide range of Gram-negative and Gram-positive organisms, including many of clinical significance. All of the triclosan glycosides that were synthesized demonstrated antibacterial activity against many of the organisms that were examined. For example, ß-galactoside (3a) and α-arabinoside (3c) had MIC values of 0.5 µg/ml for several strains of S. aureus and S. haemolyticus. The triclosan glycosides were also generally found to be more water soluble and much more selective than the underivatized triclosan, making them ideal both for the targeted inhibition of bacterial growth and as agents for the selective recovery of bacteria from mixed cultures. In the latter case, two Bacillus strains could be identified from various strains of Bacillus and Staphylococcus after inoculation onto Nutrient Agar No. 2 with 0.25 µg/ml triclosan-α-D-glucopyranoside (3e). This glucoside may, therefore, be of use for the isolation and identification of the food-poisoning organism Bacillus cereus.

Integrated disperser freezing purification with extraction using fatty acid-based solidification of floating organic-droplet (IDFP-EFA-SFO) for triclosan and methyltriclosan determination in seawater, sediment and seafood.

A microextraction method for the determination of triclosan and methyltriclosan in marine environmental samples was developed. The disperser was first serves as a preliminary extractant for analytes, then as a frozen solvent to remove impurities at -20 °C, and finally as a disperser agent in the microextraction procedure. With the extractants solidified and float on the surface of the aqueous phase at low temperature, a separation was achieved to avoided use of specialized laboratory instruments. The method was optimized using Plackett-Burman design and central composite design as follows: 146 µL octanoic acid as extractant, 793 µL acetoneas disperser, 3.0 min centrifugation and 1.1 min vortex time. The limits of detection were 0.022-0.060 µg L-1 or µg kg-1 and recoveries were 83.3-103.5% for TCS and MTCS in seawater, sediments and seafood. The method has excellent prospects for sample pre-treatment and trace-level analysis of triclosan and methyltriclosan in marine environmental samples.

Extraction of triclosan and methyltriclosan in human fluids by in situ ionic liquid morphologic transformation.

Herein, we established an ionic liquid (IL)-based liquid-solid transformation microextraction (IL-LTME) combined with HPLC-UV detection for the simultaneous determination of triclosan (TCS) and its methylated product, methyltriclosan (MTCS), in human fluids. The IL-LTME method was based on an in situ metathesis between hydrophilic IL and ion-exchange salt to form a solid hydrophobic IL. According to the above principle, a hydrophilic IL, [C12MIM]Br, was selected as the extractant, and NH4PF6 as ion-exchange salt. The prominent advantages of the newly developed method are: (1) the in-situ reaction between the extractant [C12MIM]Br and ion-exchange salt NH4PF6 changed the IL from hydrophilic to hydrophobic that avoiding the stick of ionic liquid on the tube wall; (2) bubbling with NH3 greatly increased the contact area between IL-extractant and analytes resulting in improved extraction recovery; and (3) solidification of the [C12MIM] PF6 provided a good separation and avoided the use of specialized equipment. A series of main parameters were optimized by single-factor screening and central composite design as follows: 0.9 mL of NaOH, 2.0 min of second ultrasonically time, 10 min of centrifugation time, 21 mg of extractant [C12MIM]PF6, 2.4 min of ultrasonic time, 65 mg of NH4PF6 and 13.8 min of cooling time. Under the optimized conditions, the limits of detection for TCS and MTCS were 0.126-0.161 µg L-1 in plasma samples, and 0.211-0.254 µg L-1 in urine samples, respectively. The extraction recoveries for TCS and MTCS were in the range of 94.1-103.8%. The intra-day and inter-day precisions were 1.00-4.74% and 1.02-5.21%, respectively. In general, the IL-LTME method is environment-friendly, time-saving, economical, high efficient and robust with low detection limits and high recoveries. Thus, the newly developed method has excellent prospects for sample pretreatment and analysis of trace TCS and MTCS in blood and urine samples.

A novel naphthalene carboxylic acid-based ionic liquid mixed disperser combined with ultrasonic-enhanced in-situ metathesis reaction for preconcentration of triclosan and methyltriclosan in milk and eggs.

A microextraction method was developed based on utilization of a novel ionic liquid (IL) [C4MIM][NCA] as disperser and conventional ILs as extractor (IL-IL-DLLME). This method was integrated with an in-situ metathesis reaction to achieve high extraction efficiency by eliminating the loss of analytes in the discarded disperser after microextraction. Ultrasonic energy was compared to traditional mechanical shaking to accelerate the in-situ metathesis reaction. A 3-min ultrasonic treatment provided similar extraction efficiency as a 120-min mechanical shaking. Due to their strong acidity and lower solubility than traditional hydrophilic ILs, utilization of [C4MIM][NCA] in the IL-IL-DLLME procedure increased extraction recoveries (ERs) for triclosan (TCS) and methyltriclosan (MTCS) by 10-12% and also avoided an extra pH adjustment step. A series of operational parameters were optimized using single-factor screening and central composite design as follows: 65 µL extraction solvent, 150 µL [C4MIM][BF4] and [C4MIM][NCA] (132/18, v/v, µL) as dispersive solvent, 0.16 g NH4PF6 and 3.3 min ultrasonic time. Under optimized conditions with a fortification of 100 µg kg-1, ERs were 92.6-93.4% for TCS and 92.7-94.2% for MTCS in bovine milk and chicken egg samples. LODs for TCS and MTCS were 0.16-0.24 µg kg-1 and the enrichment factors were 21.8-23.1. Inter- and intra-day precisions had relative standard deviations of 3.3-5.4% for the optimized method. Overall, this newly developed IL-IL-DLLME method was effective for detecting trace levels of TCS and MTCS in real-world, animal-based foods. Prominent advantages of the new method include high precision and accuracy, high extraction efficiency, simple analytical operations, and no use of organic solvents making the procedure environmentally benign.

Accumulation and sublethal effects of triclosan and its transformation product methyl-triclosan in the earthworm Eisenia andrei exposed to environmental concentrations in an artificial soil.

Municipal biosolids are increasingly used as a low-cost fertilizer in agricultural soil. Biosolids are contaminated by low concentrations (nanograms per gram dry wt range) of a large variety of organic contaminants, such as triclosan. The effect of exposure to low concentrations of organic contaminants on soil biota remains largely undocumented. We evaluated the sublethal effects of triclosan on the earthworm Eisenia andrei using an artificial soil amended with a nominal concentration of triclosan of 50 ng g-1 dry weight soil. Using a 56-d reproduction test, we monitored the effect of triclosan exposure on adult earthworm survival, growth, and reproduction. The bioaccumulation of triclosan in earthworm tissue (adults and juveniles) and degradation of triclosan were monitored. The genotoxicity of triclosan was evaluated using a comet assay (DNA damage) on adult earthworm coelomocytes. Exposure to a low concentration of triclosan had no significant effects on adult earthworm survival and DNA damage but significantly stimulated growth (p < 0.05) by 2-fold compared with controls. It also significantly affected E. andrei reproduction parameters (p < 0.05), as evidenced by an increase in the number of cocoons and juveniles and a decrease in the mean dry weight of juveniles. The bioaccumulation of triclosan in earthworms was moderate (bioaccumulation factor ∼2). In biosolid-borne trials, the bioaccumulation of methyl-triclosan in earthworm tissues was higher than that of the parent compound triclosan. We conclude that exposure to low concentrations of triclosan in artificial soil can significantly affect the growth and reproductive performance of earthworms (i.e., E. andrei). More research is required with natural soils to assess triclosan bioavailability for earthworms. Environ Toxicol Chem 2018;37:1940-1948. © 2018 SETAC.

Monitoring and mass balance analysis of endocrine disrupting compounds and their transformation products in an anaerobic-anoxic-oxic wastewater treatment system in Xiamen, China.

We investigated the occurrence, removal and mass balance of 8 endocrine disrupting compounds (EDCs), including estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), triclosan (TCS), triclocarbon (TCC), 4-n-nonyl phenol (NP) and 4-n-octyl phenol (OP), along with 5 of their transformation products (TPs), including 4-hydroxy estrone (4-OH E1), 4-hydroxy estradiol (4-OH E2), methyl triclosan (MeTCS), carbanilide (NCC), dichlorocarbanilide (DCC) in a wastewater treatment plant. Generally, E3 showed the highest concentrations in wastewater with median value of 514 ng/L in influent, while TCS and TCC showed highest level in sludge and suspended solids (SS) with median value of 960 and 724 µg/kg, respectively. Spatial variations were observed along each unit of the wastewater treatment processes for dissolved analytes in wastewater and adsorbed analytes in suspended solids and sludge. Special emphasis was placed to understand the mass load of EDCs and their TPs to the wastewater treatment unit and mass loss during the wastewater treatment processes. Mass loss based on both aqueous and suspended phase concentration revealed that majority of these chemicals were significantly removed during the treatment process except for TCS, TCC, and three of their TPs (MeTCS, NCC, DCC), which were released or generated during the treatment process. Mass load results showed that 42.4 g of these EDCs and their TPs entered this wastewater treatment system daily via influent, whereas 6.15 g and 7.60 g were discharged through effluent and sludge.