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

New insight into intestinal toxicity accelerated by aged microplastics with triclosan: Inflammation regulation by gut microbiota-bile acid axis

The combined toxic effects of microplastics (MPs) and their carried contaminants on organisms have been widely concerned; however, the health risks and its mechanism of "gut microbiota-host metabolism (bile acids, BA)" remain unknown. Herein, Xenopus tropicalis were exposured to aged polystyrene MPs carried triclosan (aPS+TCS) and single (a)PS-MPs & TCS, respectively. The bioaccumulation of TCS in the gut of X. tropicalis was significantly increased in aPS+TCS group, which was 89 % higher than that of PS+TCS group, causing more severe oxidative stress, inflammation and intestinal barrier disruption (leaky gut). The expressions of TNF-α, IL-6 and IL-10 in aPS+TCS group were enhanced by 276 % and 19 % and decreased by 81 %, respectively, compared to that in PS+TCS group. Moreover, co-exposure to aPS+TCS increased the number of Escherichia coli, and reduced levels of DCA and LCA (secondary BAs). Multiomics analysis further revealed that the intestinal toxicity of aPS+TCS to X. tropicalis was mainly influenced by the gut flora, BA metabolism and inflammation-related pathways. Co-exposure may exacerbate inflammation by increasing the blood levels of lipopolysaccharides and inhibiting secondary BA production, which are regulated by the gut microbiota-bile acid axis. This study provides new insights in the potential mechanisms of intestinal damage from pollutant-loaded aged MPs.

Long-term and low-dose exposure to triclosan induces POI phenotype in female offspring mice

Triclosan (TCS), a typical endocrine disruptor, is widely used as an antibacterial agent in consumer goods. However, there are few studies on the effects of long-term low-dose TCS exposure on ovarian function in F1 female mice. In this paper, F1 female mice were exposed to TCS (0-3000 μg/kg/day) from intrauterine to postnatal day (PND) 91 to investigate its effects on the ovary. The results revealed that the number of total follicles was decreased, while atretic follicles was increased after TCS exposure. At the hormonal level, the secretion of estradiol was reduced, while follicle-stimulating hormone and luteinizing hormone were increased after TCS exposure. Observation of vaginal smear showed that TCS disrupted the estrous cycle of F1 female mice, especially at the dose of 3000 μg/kg/day. Moreover, TCS promoted cell apoptosis by activating the p38-MAPK signaling pathway and oxidative stress in vitro. In addition, analysis of the fecal microbiome and serum metabolomics revealed that exposure to TCS may cause gut microbiota disruption and metabolic abnormalities in F1 female mice. In conclusion, long-term low-dose TCS exposure may induce primary ovarian insufficiency phenotype in F1 female mice via inducing cell apoptosis and disrupting gut microbiota and metabolism.

Modified vermiculite as a sorbent phase for stir-bar sorptive extraction

BACKGROUND

The presence of emerging contaminants (ECs) is a cause of great concern nowadays, and they are present at very low concentrations in surface waters, requiring a preconcentration process for their reliable quantification. The technique of Stir-Bar Sorptive Extraction (SBSE) is a valuable tool for achieving this purpose, and different sorbents have been developed to produce the bars. In this sense, we propose the use of the clay mineral vermiculite (Vt), modified with alkylammonium salts, aiming the determination of the ECs: bisphenol A, diclofenac, ibuprofen and triclosan in surface water samples.

RESULTS

The best conditions for sorption and desorption were: 50.0 mL of sample at pH 4.0, under stirring at 600 rpm (120 min), being the desorption carried out under sonication for 20 min using 500 μL of methanol, and the analytes were determined using LC-DAD. A linear range from 0.50 to 2.50 μg L-1 or from 0.50 to 5.00 μg L-1 and R2 higher than 0.9480 were observed, and attractive real enrichment factors between 116 and 177 times, affording a LOD between 0.11 and 0.33 μg L-1. The method was applied to determine the four ECs in samples of tap, river, and lake waters, presenting recovery results between 42.0 and 128.0 %, and RSD from 0.4 to 19.6 %. The bars prepared using Vt presented good chemical and mechanical resistance, even modified using the alkylammonium salts, permitting them to be employed at least 30 times, without memory effects.

SIGNIFICANCE

The modified Vt, afforded a simple, low-cost, and attractive alternative to work as a sorbent phase for SBSE technique, presenting very appropriate analytical parameters, even employing LC-DAD. Although the sorbent was applied to a limited number of contaminants, it is probable that other analytes could be successfully determined. It is important to notice that this is the first study reported, employing modified Vt for SBSE application.

Resistance and Biodegradation of Triclosan and Propylparaben by Isolated Bacteria from Greywater

We investigated the relationship between antibiotic-resistance genes and the antimicrobial agents, triclosan (TCS) and propylparaben (PPB). The greywater microbiome was repeatedly exposed to triclosan and propylparaben and the effect was analyzed using a combination of PCR, Etest, Biolog, 16S rRNA sequencing, and liquid chromatography. The taxonomic identification points to very similar or even identical isolates, however, the phenotypic analysis suggests that their metabolic potential is different, likely due to genomic variation or differences in the expression of the substrate utilization pathways. For both triclosan and propylparaben, the antibiotic resistance levels among isolates remain consistent regardless of the exposure duration. This suggests that antibiotic-resistance genes are acquired rapidly and that their presence is not directly proportional to the level of micropollutant exposure. In a biodegradation test, TCS was reduced by 50% after 7 h, while PPB decreased only after 75 h. For TCS, the minimal inhibition concentration (MIC) ranged from 64 to above 256 mg/mL. Conversely, for PPB the MIC for the tested strains ranged between 512 and 800 mg/mL. This study highlights the complex interaction between household xenobiotics, greywater microorganisms, and the emergence of antibiotic resistance.

Unveiling the effect of urinary xenoestrogens on chronic kidney disease in adults: A machine learning model

Exposure to three primary xenoestrogens (XEs), including phthalates, parabens, and phenols, has been strongly associated with chronic kidney disease (CKD). An interpretable machine learning (ML) model was developed to predict CKD using data from the National Health and Nutrition Examination Survey (NHANES) database spanning from 2007 to 2016. Four ML algorithms-random forest classifier (RF), XGBoost (XGB), k-nearest neighbors (KNN), and support vector machine (SVM)-were used alongside traditional logistic regression to predict CKD. The study included 6910 U.S. adults, with XGB showing the highest predictive accuracy, achieving an area under the curve (AUC) of 0.817 (95 % CI: 0.789, 0.844). The selected model was interpreted using Shapley additive explanations (SHAP) and partial dependence plot (PDP). The SHAP method identified key predictive features for CKD in urinary metabolites of XEs-methyl paraben (MeP), mono-(carboxynonyl) phthalate (MCNP), and triclosan (TCS)-and suggested personalized CKD care should focus on XE control. PDP results confirmed that, within certain ranges, MeP levels positively impacted the model, MCNP levels negatively impacted it, and TCS had a mixed effect. The synergistic effects suggested that managing urinary MeP levels could be essential for the effective control of CKD. In summary, our research highlights the significant predictive potential of XEs for CKD, especially MeP, MCNP, and TCS.

Plastic additives as a new threat to the global environment: Research status, remediation strategies and perspectives

Discharge or leaching of plastic additives, which are an essential part of the plastic production process, can lead to environmental pollution with serious impacts on human and ecosystem health. Recently, the emission of plastic additives is increasing dramatically, but its pollution condition has not received enough attention. Meanwhile, the effective treatment strategy of plastic additive pollution is lack of systematic introduction. Therefore, it is crucial to analyze the harm and pollution status of plastic additives and explore effective pollution control strategies. This paper reviews the latest research progress on additives in plastics, describes the effects of their migration into packaged products and leaching into the environment, presents the hazards of four major classes of plastic additives (i.e., plasticizers, flame retardants, stabilizers, and antimicrobials), summarizes the existing abiotic/biotic strategies for accelerated the remediation of additives, and finally provides perspectives on future research on the removal of plastic additives. To the best of our knowledge, this is the first review that systematically analyzes strategies for the treatment of plastic additives. The study of these strategies could (i) provide feasible, cost-effective abiotic method for the removal of plastic additives, (ii) further enrich the current knowledge on plastic additive bioremediation, and (iii) present application and future development of plants, invertebrates and machine learning in plastic additive remediation.

Which emerging micropollutants deserve more attention in wastewater in the post-COVID-19 pandemic period? Based on distribution, risk, and exposure analysis

Aggravated accumulation of emerging micropollutants (EMs) in aquatic environments, especially after COVID-19, raised significant attention throughout the world for safety concerns. This article reviews the sources and occurrence of 25 anti-COVID-19 related EMs in wastewater. It should be pointed out that the concentration of anti-COVID-19 related EMs, such as antivirals, plasticizers, antimicrobials, and psychotropic drugs in wastewater increased notably after the pandemic. Furthermore, the ecotoxicity, ecological, and health risks of typical EMs before and after COVID-19 were emphatically compared and analyzed. Based on the environmental health prioritization index method, the priority control sequence of typical EMs related to anti-COVID-19 was identified. Lopinavir (LPV), venlafaxine (VLX), di(2-ethylhexyl) phthalate (DEHP), benzalkonium chloride (BAC), triclocarban (TCC), di-n-butyl phthalate (DBP), citalopram (CIT), diisobutyl phthalate (DIBP), and triclosan (TCS) were identified as the top-priority control EMs in the post-pandemic period. Besides, some insights into the toxicity and risk assessment of EMs were also provided. This review provides direction for proper understanding and controlling the EMs pollution after COVID-19, and is of significance to evaluate objectively the environmental and health impacts induced by COVID-19.

Novel MoS2-In2O3-WS2 (2D/3D/2D) ternary heterostructure nanocomposite material: Efficient photocatalytic degradation of antimicrobial agents under visible-light

Fabrication of ternary composited photocatalytic nanomaterials with strong interaction is vital to deriving the fast charge separation for efficient photodegradation of organic contaminants in wastewater under visible light. In this work, novel ternary 2D/3D/2D MoS2-In2O3-WS2 multi-nanostructures were synthesized using facile hydrothermal processes. XRD, FTIR, and XPS results confirmed the phase, functional groups, and element composition of pure MoS2, MoS2-In2O3, and MoS2-In2O3-WS2 hybrids. UV-DRS spectra of the MoS2-In2O3-WS2 ternary hybrid indicate maximum absorption in the visible light range with a band-gap energy value of 2.4 eV. The surface of the 2D WS2 nanosheet structure tightly blends and densely disperses 2D MoS2 nanosheets and 3D In2O3 nanocubes. This confirmed the formation of the MoS2-In2O3-WS2 ternary hybrid in the form of 2D/3D/2D multi-nanostructures, which is also indicated from SEM and HR-TEM images. The synthesized MoS2-In2O3-WS2 ternary hybrid showed maximum photocatalytic activity under visible-light for antimicrobial agents such as triclosan (TCS) and trichlorocarban (TCC). The photocatalytic activity of TCS was revealed to be 95% at 90 min, while that of TCC was 93% at 100 min. The reusability and stability tests of the prepared MoS2-In2O3-WS2 ternary hybrid after four consecutive photocatalytic cycles were analyzed by FTIR and SEM, which indicated that the prepared ternary hybrid was very stable. Overall results suggested that the developed MoS2-In2O3-WS2 (2D/3D/2D) multi-nanostructures are environmentally friendly and low-cost nanocomposites as a potential photocatalyst for the removal of antimicrobial agents from wastewater.

Neurotoxic effects of triclosan in adolescent mice: Pyruvate kinase M2 dimer regulated Signal transducer and activator of transcription 3 phosphorylation mediated microglia activation and neuroinflammation

Triclosan (TCS), a commonly used antibacterial agent, is associated with various harmful effects on mammalian neurodevelopment, particularly when exposed prenatally. This study investigated the impact of long-term exposure to TCS on the prefrontal cortex development in adolescent mice. We evaluated the motor ability, motor coordination, and anxiety behavior of mice using open field tests (OFT) and elevated cross maze tests (EPM). An increase in movement distance, number of passes through the central area, and open arm retention time was observed in mice treated with TCS. Hematoxylin eosin staining and Nissl staining also showed significant adverse reactions in the brain tissue of TCS-exposed group. TCS induced microglia activation and increased inflammatory factors expression in the prefrontal cortex. TCS also increased the expression of pyruvate kinase M2 (PKM2), thereby elevating the levels of PKM2 dimer, which entered the nucleus. Treatment with TEPP46 (PKM2 dimer nuclear translocation inhibitor) blocked the expression of inflammatory factors induced by TCS. TCS induced the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3) in vivo and in vitro, upregulating the levels of inflammatory cytokines. The results also demonstrated the binding of PKM2 to STAT3, which promoted STAT3 phosphorylation at the Tyr705 site, thereby regulating the expression of inflammatory factors. These findings highlight the role of PKM2-regulated STAT3 phosphorylation in TCS-induced behavioral disorders in adolescents and propose a reliable treatment target for TCS.

Triclosan-loaded aged microplastics exacerbate oxidative stress and neurotoxicity in Xenopus tropicalis tadpoles via increased bioaccumulation

Microplastics and chlorine-containing triclosan (TCS) are widespread in aquatic environments and may pose health risks to organisms. However, studies on the combined toxicity of aged microplastics and TCS are limited. To investigate the toxic effects and potential mechanisms associated with co-exposure to TCS adsorbed on aged polyethylene microplastics (aPE-MPs) at environmentally relevant concentrations, a 7-day chronic exposure experiment was conducted using Xenopus tropicalis tadpoles. The results showed that the overall particle size of aPE-MPs decreased after 30 days of UV aging, whereas the increase in specific surface area improved the adsorption capacity of aPE-MPs for TCS, resulting in the bioaccumulation of TCS under dual-exposure conditions in the order of aPE-TCS > PE-TCS > TCS. Co-exposure to aPE-MPs and TCS exacerbated oxidative stress and neurotoxicity to a greater extent than a single exposure. Significant upregulation of pro-symptomatic factors (IL-β and IL-6) and antioxidant enzyme activities (SOD and CAT) indicated that the aPE-TCS combination caused more severe oxidative stress and inflammation. Molecular docking revealed the molecular mechanism of the direct interaction between TCS and SOD, CAT, and AChE proteins, which explains why aPE-MPs promote the bioaccumulation of TCS, causing increased toxicity upon combined exposure. These results emphasize the need to be aware of the combined toxicity caused by the increased ability of aged microplastics to carry contaminants.

Parabens and triclosan in red swamp crayfish (Procambarus clarkii) from China: Concentrations, tissue distribution and related human dietary intake risk

Parabens (PBs) and triclosan (TCS) are commonly found in pharmaceuticals and personal care products (PPCPs). As a result, they have been extensively found in the environment, particularly in aquaculture operations. Red swamp crayfish (Procambarus clarkii) consumption has significantly risen in China. Nevertheless, the levels of PBs and TCS in this species and the associated risk to human dietary intake remain undisclosed. This study assessed the amounts of five PBs, i.e., methyl-paraben (MeP), ethyl-paraben (EtP), propyl-paraben (PrP), butyl-paraben (BuP) and benzyl-paraben (BzP), as well as TCS in crayfish taken from five provinces of the middle-lower Yangtze River. MeP, PrP and TCS showed the highest detection rates (hepatopancreas: 46-86 %; muscle: 63-77 %) since they are commonly used in PPCPs. Significantly higher levels of ∑5PBs (median: 3.69 ng/g) and TCS (median: 7.27 ng/g) were significantly found in the hepatopancreas compared to the muscle (median: 0.39 ng/g for ∑5PBs and 0.16 ng/g for TCS) (p < 0.05), indicating bioaccumulation of these chemicals in the hepatopancreas. The estimated daily intake values of ∑5PBs and TCS calculated from the median concentrations of crayfish were 6.44-7.94 ng/kg bw/day and 11.4-14.0 ng/kg bw/day, respectively. Although no health risk was predicted from consuming crayfish (HQ <1), consumption of the hepatopancreas is not recommended.

The pleiotropic role of Salinicoccus bacteria in enhancing ROS homeostasis and detoxification metabolism in soybean and oat to cope with pollution of triclosan

Triclosan has been extensively used as a preservative in cosmetics and personal care products. However, its accumulation represents a real environmental threat. Thus, its phytotoxic impact needs more consideration. Our study was conducted to highlight the phytotoxic effect of triclosan on the growth, ROS homeostasis, and detoxification metabolism of two different plant species i.e., legumes (Glycine max) and grass (Avena sativa). Moreover, we investigated the potentiality of plant growth-promoting bacteria (ST-PGPB) in mitigating the phytotoxic effect of triclosan. Triclosan induced biomass (fresh and dry weights) reduction in both plants, but to a higher extent in oats. This decline was associated with a noticeable increment in the oxidative damage (e.g., MDA and H2O2) and detoxification metabolites such as metallothionein (MTC), phytochelatins (PCs), and glutathione-S-transferase (GST). This elevation was associated with a remarkable reduction in both enzymatic and non-enzymatic antioxidants. On the other hand, the bioactive strain of ST-PGPB, Salinicoccus sp. JzA1 significantly alleviated the harmful effect of triclosan on both soybean and oat plants by enhancing their biomass, photosynthesis, as well as levels of minerals (K, Ca, P, Mn, and Zn). In parallel, a striking quenching in oxidative damage and an obvious improvement in non-enzymatic (polyphenols, tocopherols, flavonoids) and enzymatic antioxidants were observed. Furthermore, Salinicoccus sp. JzA1 augmented the detoxification metabolism by enhancing the levels of phytochelatins, metallothionein, and glutathione-S-transferase (GST) activity in a species-specific manner which is more apparent in soybean rather than in oat plants. To this end, stress mitigating impact of Salinicoccus sp. JzA1 provides a basis to improve the resilience of crop species under cosmetics and personal care products toxicity.

Insight into the enhancement effect of humic acid on microbial degradation of triclosan in anaerobic sediments

Humic acid (HA) as one class of macromolecular substances plays important roles in mediating environmental behaviors of pollutants in sediments, but its effect on microbial degradation of triclosan (TCS), a common antibacterial drug, remains unclear. In this study, the effects of HA addition with different dosages (0-5%) on TCS degradation in anaerobic sediment slurries and the underlying microbial mechanisms were investigated. The results showed that HA addition significantly accelerated the TCS removal and the maximum removal percentage (30.2%) was observed in the sediment slurry with 5% HA addition. The iron reduction rate, relative abundances of the genera Comamonas, Pseudomonas and Geobacter, and bacterial network complexity in sediment slurry were significantly enhanced due to HA addition. Based on the partial least squares path modeling analysis, the enhancement effect of HA on TCS degradation was mainly explained by Fe(II):Fe(III) ratio with the highest influence on TCS removal (total effect: 0.723), followed by dominant genera abundances (total effect: 0.391), module relative abundance (total effect: 0.272), and network topological features (total effect: 0.263). This finding enhanced our understanding of the role of HA in TCS biodegradation in contaminated sediments for bioremediation purposes.

Chronic triclosan exposure induce impaired glucose tolerance by altering the gut microbiota

Triclosan (TCS) is an antimicrobial compound incorporated into more than 2000 consumer products. This compound is frequently detected in the human body and causes ubiquitous contamination in the environment, thereby raising concerns about its impact on human health and environmental pollution. Here, we demonstrated that 20 weeks' exposure of TCS drove the development of glucose intolerance by inducing compositional and functional alterations in intestinal microbiota in rats. Fecal-transplantation experiments corroborated the involvement of gut microbiota in TCS-induced glucose-tolerance impairment. 16S rRNA gene-sequencing analysis of cecal contents showed that TCS disrupted the gut microbiota composition in rats and increased the ratio of Firmicutes to Bacteroidetes. Cecal metabolomic analyses detected that TCS altered host metabolic pathways that are linked to host glucose and amino acid metabolism, particularly branched-chain amino acid (BCAA) biosynthesis. BCAA measurement confirmed the increase in serum BCAAs in rats exposed to TCS. Western blot and immunostaining results further confirmed that elevated BCAAs stimulated mTOR, a nutrient-sensing complex, and following IRS-1 serine phosphorylation, resulted in insulin resistance and glucose intolerance. These results suggested that TCS may induce glucose metabolism imbalance by regulating BCAA concentration by remodeling the gut microbiota.

Associations of urinary non-persistent endocrine disrupting chemical biomarkers with early-to-mid pregnancy plasma sex-steroid and thyroid hormones

BACKGROUND/OBJECTIVES

Pregnant women are exposed to numerous endocrine disrupting chemicals (EDCs) that can affect hormonal pathways regulating pregnancy outcomes and fetal development. Thus, we evaluated overall and fetal sex-specific associations of phthalate/replacement, paraben, and phenol biomarkers with sex-steroid and thyroid hormones.

METHODS

Illinois women (n = 302) provided plasma for progesterone, estradiol, testosterone, free T4 (FT4), total T4 (TT4), and thyroid stimulating hormone (TSH) at median 17 weeks gestation. Women also provided up-to-five first-morning urine samples monthly across pregnancy (8-40 weeks), which we pooled to measure 19 phthalate/replacement metabolites (reflecting ten parent compounds), three parabens, and six phenols. We used linear regression to evaluate overall and fetal sex-specific associations of biomarkers with hormones, as well as weighted quantile sum and Bayesian kernel machine regression (BKMR) to assess cumulative associations, non-linearities, and chemical interactions.

RESULTS

In women of relatively high socioeconomic status, several EDC biomarkers were associated with select hormones, without cumulative or non-linear associations with progesterone, FT4, or TT4. The biomarker mixture was negatively associated with estradiol (only at higher biomarker concentrations using BKMR), testosterone, and TSH, where each 10% mixture increase was associated with -5.65% (95% CI: -9.79, -1.28) lower testosterone and -0.09 μIU/mL (95% CI: -0.20, 0.00) lower TSH. Associations with progesterone, testosterone, and FT4 did not differ by fetal sex. However, in women carrying females, we identified an inverted u-shaped relationship of the mixture with estradiol. Additionally, in women carrying females, each 10% increase in the mixture was associated with 1.50% (95% CI: -0.15, 3.18) higher TT4, whereas in women carrying males, the mixture was associated with -1.77% (95% CI: -4.08, 0.58) lower TT4 and -0.18 μIU/mL (95% CI: -0.33, -0.03) lower TSH. We also identified select chemical interactions.

CONCLUSION

Some biomarkers were associated with early-to-mid pregnancy hormones. There were some sex-specific and non-linear associations. Future studies could consider how these findings relate to pregnancy/birth outcomes.

Revealing mechanisms of triclosan on the removal and distribution of nitrogen and phosphorus in microalgal-bacterial symbiosis system

Microalgal-bacterial symbiosis (MABS) system performs synergistic effect on the reduction of nutrients and carbon emissions in the water treatment process. However, antimicrobial agents are frequently detected in water, which influence the performance of MABS system. In this study, triclosan (TCS) was selected to reveal the effects and mechanisms of antimicrobial agents on MABS system. Results showed that the removal efficiencies of chemical oxygen demand, NH4+-N and total phosphorus decreased by 3.0%, 24.0% and 14.3% under TCS stress. In contrast, there were no significant decrease on the removal effect of total nitrogen. Mechanism analysis showed that both the growth rate of microorganisms and the nutrients retention capacity of extracellular polymeric substances were decreased. The intracellular accumulation for nitrogen and phosphorus was promoted due to the increased cytomembrane permeability caused by lipid peroxidation. Moreover, microalgae were dominant in MABS system with ratio between microalgae and bacteria of more than 5.49. The main genus was Parachlorella, with abundance of more than 90%. Parachlorella was highly tolerant to TCS, which might be conductive to maintain its survival. This study revealed the nutrients pathways of MABS system under TCS stress, and helped to optimize the operation of MABS system.