Occurrence of triclosan, triclocarban, and its lesser chlorinated congeners in Minnesota freshwater sediments collected near wastewater treatment plants

Sequential Reductive Dechlorination of Triclosan by Sediment Microbiota Harboring Organohalide-Respiring Dehalococcoidia

Aquatic ecosystems represent a prominent reservoir of xenobiotic compounds, including triclosan (TCS), a broad-spectrum biocide extensively used in pharmaceuticals and personal care products. As a biogeochemical hotspot, the potential of aquatic sediments for the degradation of TCS remains largely unexplored. Here, we demonstrated anaerobic biotransformation of TCS in a batch microcosm established with freshwater sediment. The initial 43.4 ± 2.2 μM TCS was completely dechlorinated to diclosan, followed by subsequent conversion to 5-chloro-2-phenoxyphenol, a monochlorinated TCS (MCS) congener. Analyses of community profile and population dynamics revealed substrate-specific, temporal-growth of Dehalococcoides and Dehalogenimonas, which are organohalide-respiring bacteria (OHRB) affiliated with class Dehalococcoidia. Dehalococcoides growth was linked to the formation of diclosan but not MCS, yielding 3.6 ± 0.4 × 107 cells per μmol chloride released. A significant increase in Dehalogenimonas cells, from 1.5 ± 0.4 × 104 to 1.5 ± 0.3 × 106 mL-1, only occurred during the reductive dechlorination of diclosan to MCS. Dehalococcoidia OHRB gradually disappeared following consecutive transfers, likely due to the removal of sediment materials with strong adsorption capacity that could alleviate TCS's antimicrobial toxicity. Consequently, a solid-free, functionally stable TCS-dechlorinating consortium was not obtained. Our results provide insights into the microbial determinants controlling the environmental fate of TCS.

Exploring environmental obesogenous effects of organic ultraviolet filters on children from a case-control study

It has been globally recognized that obesity has become a major public health concern, especially childhood obesity. There is limited information, however, regarding the exposure risk of organic ultraviolet (UV) filters, a kind of emerging contaminant, on childhood obesity. This study would be made on 284 obese and 220 non-obese Chinese children with eight organic UV filters at urinary levels. The eight organic UV filters, including 2-Ethylhexyl 4-aminobenzoate (PABA-E), octisalate (EHS), homosalate (HMS), 2-Ethylhexyl-p-methoxycinnamate (EHMC), benzophenone-3 (BP-3), amiloxate (IAMC), octocrylene (OC) and 4-Methylbenzylidene camphor (4-MBC) were identified in urine samples with detection rates ranged from 35.32% to 100%, among which PABA-E, HMS, IAMC and OC were firstly detected in children' s urine. And the urinary UV filters concentration was associated with genders, living sites, guardian education levels, household income, and dietary factors. Urinary EHMC concentrations and childhood obesity were positively associated for girls [Adjusted OR = 2.642 (95% CI: 1.019, 6.853)], while OC concentrations and childhood obesity were negatively associated for girls [Adjusted OR = 0.022 (95% CI: 0.001, 0.817)]. The results suggest that EHMC exposure may be an environmental obesogen for girls. Moreover, two statistical models were used separately to evaluate the impact of UV filter mixtures on childhood obesity, including the Bayesian kernel machine regression (BKMR) model and the quantile g-computation (qgcomp) model. The negative association between UV filter mixtures and childhood obesity was proposed from both BKMR and qgcomp models. Further experimental and epidemiological studies are called upon to discern the individual and mixture impacts of organic UV filters on childhood obesity.

In vitro metabolism of triclosan and chemoprevention against its cytotoxicity

Triclosan (TCS), a broad-spectrum antibacterial chemical, has been extensively used in personal daily care items, household commodities, and clinical medications; therefore, humans are at risk of being exposed to TCS in their daily lives. This chemical also accumulated in food chains, and potential risks were associated with its metabolism in vivo. The aim of this study was to investigate the difference in metabolic profile of TCS by hepatic P450 enzymes and extrahepatic P450s, and also identify chemical structures of its metabolites. The results showed that RLM mediated the hydroxylation and cleavage of the ether moiety of TCS, resulting in phenolic metabolites that are more polar than the parent compound, including 4-chlorocatechol, 2,4-dichlorophenol and monohydroxylated triclosan. The major metabolite of CYP1A1 and CYP1B1 mediated TCS metabolism is 4-chlorochol. We also performed molecular docking experiments to investigate possible binding modes of TCS in the active sites of human CYP1B1, CYP1A1, and CYP3A4. In addition to in vitro experiments, we further examined the cytotoxic effects of TCS on HepG2 cells expressing hepatic P450 and MCF-7/1B1 cells expressing CYP1B1. It exhibited significant cytotoxicity on HepG2, MCF-10A and MCF-7/1B1 cells, with IC50 values of 70 ± 10 μM, 20 ± 10 μM and 60 ± 20 μM, respectively. The co-incubation of TCS with glutathione (GSH) as a chemopreventive agent could reduce the cytotoxicity of TCS in vitro. The chemopreventive effects of GSH might be ascribed to the promotion of TCS efflux mediated by membrane transporter MRP1 and also its antioxidant property, which partially neutralized the oxidative stress of TCS on mammalian cells. This study contributed to our understanding of the relationship between the P450 metabolism and the toxicity of TCS. It also had implications for the use of specific chemopreventive agents against the toxicity of TCS.

Occurrence and risk evaluation of endocrine-disrupting chemicals in wastewater and surface water of Lahore, Pakistan

The current study highlights the occurrence, spatial distribution, and risk assessment of 16 endocrine-disrupting chemicals (EDCs) including their transformation products (TPs) in the wastewater and surface water of Lahore, Pakistan, using solid-phase extraction followed by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The parent EDCs include bisphenol A (BPA), triclosan (TCS), triclocarban (TCC), estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), 4-n-octylphenol (4n-OP), and 4-n-nonylphenol (4n-NP). The TPs include two TPs each of BPA, TCC, and estrogens along with a TP of TCS. Most EDCs showed 100% detection frequency in the wastewater with highest median concentration of 1310 ng/L for E3. In the surface water, the highest median concentration was, however, observed for BPA (54.6 ng/L). Spatial variations in terms of sum of concentration due to all EDCs and their TPs were observed at different sampling points which suggest contamination due to industrial waste from nearby industrial estate. Risk evaluation in terms of risk quotient (RQ) and estradiol equivalent factor (EEQ) showed that most of EDCs and their TPs could pose high risk and estrogenicity to the surrounding environment. From the results of the current study, it is observed that the environment of Pakistan is deteriorating and is potential risk for endocrine disruption. It is, therefore, recommended to take stringent measures to make it sustainable for current as well as for future generations.

Biotreatment efficiency, degradation mechanism and bacterial community structure in an immobilized cell bioreactor treating triclosan-rich wastewater

Biotreatment of triclosan is mainly performed in conventional activated sludge systems, which, however, are not capable of completely removing this antibacterial agent. As a consequence, triclosan ends up in surface and groundwater, constituting an environmental threat, due to its toxicity to aquatic life. However, little is known regarding the diversity and mechanism of action of microbiota capable of degrading triclosan. In this work, an immobilized cell bioreactor was setup to treat triclosan-rich wastewater. Bioreactor operation resulted in high triclosan removal efficiency, even greater than 99.5%. Nitrogen assimilation was mainly occurred in immobilized biomass, although nitrification was inhibited. Based on Illumina sequencing, Bradyrhizobiaceae, followed by Ferruginibacter, Thermomonas, Lysobacter and Gordonia, were the dominant genera in the bioreactor, representing 38.40 ± 0.62% of the total reads. However, a broad number of taxa (15 genera), mainly members of Xanthomonadaceae, Bradyrhizobiaceae and Chitinophagaceae, showed relative abundances between 1% and 3%. Liquid Chromatography coupled to Quadrupole Time-Of-Flight Mass Spectrometry (LC-QTOF-MS) resulted in the identification of catabolic routes of triclosan in the immobilized cell bioreactor. Seven intermediates of triclosan were detected, with 2,4-dichlorophenol, 4-chlorocatechol and 2-chlorohydroquinone being the key breakdown products of triclosan. Thus, the immobilized cell bioreactor accommodated a diverse bacterial community capable of degrading triclosan.

The last 50 years of organic contamination of a highly anthropized tributary of the Po River (Italy)

We examined the temporal profiles of many organic micropollutants analysed in a sediment core sampled from a highly anthropized tributary of the Po River, the Lambro River. Analysed for extractable organic halogens (EOX), total petroleum hydrocarbons (C₁₀-C₄₀TPH), polycyclic aromatic hydrocarbons (PAHs), common legacy pollutants (DDTs, PCBs), halogenated flame retardants (PBDEs, DBDPE, TBBPA-bis, TCBPA, TBBPA, HBCDs), organotins (TBT, TPhT), antimicrobials (TCS, TCC), fragrances (AHTN, HHCB) and phthalates (DMP, DEP, DnBP, BBP, DEHP, DnOP), the dated sediment core revealed the historical record of 50 years of chemical contamination discharged into the Lambro and thereby the Po River. In this regard, the peak levels of PCBs and DDTs found in Lambro sediments were also identified in other sediment cores collected from the Po River prodelta in the Adriatic Sea, thus hundreds of kilometres downstream (Combi et al., 2020). The highest risk to aquatic organisms was associated with decades of high levels of C₁₀-C₄₀ TPH, PBDEs, PCBs, PAHs, DDTs, EOX, TCC, AHTN and DEHP, which in different periods of the contamination history, showed exceedances of guideline/threshold values. C₁₀-C₄₀ TPH and TCC, for example, were very high in the 1960s, whereas PCBs, DDTs, and PBDEs, peaked from the 1980s onward. The corresponding sums of PEC quotients ranged between 0.48 and 28.63, with a mean value (±SD) for the entire recording period of 10.62 ± 9.83. Environmental legislations and improved wastewater treatments were the main drivers of the recent downward trends observed for most of the chemicals investigated. Floods in turn resulted in macroscopic yet temporary improvements in the chemical quality of the tributary, conveying contaminated sediments into the Po River.

Cosmetic Preservatives: Hazardous Micropollutants in Need of Greater Attention?

In recent years, personal care products (PCPs) have surfaced as a novel class of pollutants due to their release into wastewater treatment plants (WWTPs) and receiving environments by sewage effluent and biosolid-augmentation soil, which poses potential risks to non-target organisms. Among PCPs, there are preservatives that are added to cosmetics for protection against microbial spoilage. This paper presents a review of the occurrence in different environmental matrices, toxicological effects, and mechanisms of microbial degradation of four selected preservatives (triclocarban, chloroxylenol, methylisothiazolinone, and benzalkonium chloride). Due to the insufficient removal from WWTPs, cosmetic preservatives have been widely detected in aquatic environments and sewage sludge at concentrations mainly below tens of µg L^-1. These compounds are toxic to aquatic organisms, such as fish, algae, daphnids, and rotifers, as well as terrestrial organisms. A summary of the mechanisms of preservative biodegradation by micro-organisms and analysis of emerging intermediates is also provided. Formed metabolites are often characterized by lower toxicity compared to the parent compounds. Further studies are needed for an evaluation of environmental concentrations of preservatives in diverse matrices and toxicity to more species of aquatic and terrestrial organisms, and for an understanding of the mechanisms of microbial degradation. The research should focus on chloroxylenol and methylisothiazolinone because these compounds are the least understood.

Fate, toxicity and effect of triclocarban on the microbial community in wastewater treatment systems

Triclocarban (TCC), one of the typical antimicrobial agents, is a contaminant of emerging concern commonly found in high concentration in water environments. However, the fate and toxicity of TCC in wastewater treatment systems remain poorly understood. Here, we investigated how TCC impacts chemical oxygen demand and inorganic nitrogen transformation in a hydrolytic anaerobic-anoxic/oxic process. In the anaerobic section, the transformation of TCC was dominated by reductive dechlorination and supplemented by two amid bonds hydrolysis. In the anoxic and oxic sections, the hydrolysis of amid bonds dominated. The toxicity was reduced after the treatment (IC₅₀ from 0.09 to 0.54). TCC inhibited NH₄⁺-N removal in the anaerobic section and led to the NO₃^--N accumulation (2.84-4.13 mg/L) after treatment, with the abundance of N-removal bacteria decreased by 6%. Furthermore, the original ecological niche was gradually replaced by TCC-resistant/degradative bacteria, formating new microbial modules to resist the TCC stress. Importantly, fourteen genera including Methanosaeta, Longilinea, Dokdonella and Mycobacterium as potential bioindicators warning TCC and its intermediates were proposed. Overall, this study provides new insights into the fate of TCC in biological wastewater treatment systems and suggests a great importance for TCC control to ensure the health and resilience of ecosystems.

Occurrence, health risk assessment and water quality criteria derivation of six personal care products (PCPs) in Huangpu River, China

Personal care products (PCPs) have shown adverse health effects on humans. However, their health risk associated with fish consumption and relevant water quality criteria are still not well documented. This study investigated the occurrence and health risk of six PCPs (triclosan, bisphenol-A, and four commonly used organic ultraviolet (UV) filters, i.e., homosalate (HMS), 4-methylbenzylidene camphor (4-MBC), oxybenzone (BP-3), and octocrylene (OC)). River water and three trophic levels of fish species were collected from Huangpu River in Shanghai. The concentration range of the six PCPs were 1.48-89.76 ng/L in water and 0.40-10.75 ng/g dry weight in fish. Estimated daily intake (EDI) and target hazard quotient (THQ) of the PCPs indicated that consuming these fish would not pose non-carcinogenic risks. The maximum allowable fish consumption rates ranged from 85 to 1760 and 155 to 3230 meals per month for children and adults, respectively. As to the four organic UV filters, it is the first time to report the fish consumption advisories. Finally, the human health ambient water quality criteria (AWQC) values of HMS, 4-MBC, BP-3, OC, TCS, and BPA (i.e., 0.1218, 0.7311, 0.3494, 0.0477, 235.8, and 154.7 μg/L, respectively) were proposed, and they can serve as a valuable technical reference for global development and revision of aquatic environmental quality standards for these emerging contaminants.

Abundance, fate, and effects of pharmaceuticals and personal care products in aquatic environments

Pharmaceuticals and personal care products (PPCPs) are found in wastewater, and thus, the environment. In this study, current knowledge about the occurrence and fate of PPCPs in aquatic systems-including wastewater treatment plants (WWTPs) and natural waters around the world-is critically reviewed to inform the state of the science and highlight existing knowledge gaps. Excretion by humans is the primary route of PPCPs entry into municipal wastewater systems, but significant contributions also occur through emissions from hospitals, PPCPs manufacturers, and agriculture. Abundance of PPCPs in raw wastewater is influenced by several factors, including the population density and demography served by WWTPs, presence of hospitals and drugs manufacturers in the sewershed, disease burden of the population served, local regulations, and climatic conditions. Based on the data obtained from WWTPs, analgesics, antibiotics, and stimulants (e.g., caffeine) are the most abundant PPCPs in raw wastewater. In conventional WWTPs, most removal of PPCPs occurs during secondary treatment, and overall removal exceeds 90% for treatable PPCPs. Regardless, the total PPCP mass discharged with effluent by an average WWTP into receiving waters (7.35-20,160 g/day) is still considerable, because potential adverse effects of some PPCPs (such as ibuprofen) on aquatic organisms occur within measured concentrations found in surface waters.

Dose-response genotoxicity of triclosan in mice: an estimate of acceptable daily intake based on organ toxicity

Triclosan (TCS) is widely used and it bioaccumulates in humans. We found that TCS induced DNA damage in TK6 cell in our previous work. Herein, we performed a pilot assay of the TK6 cell/TK gene (TK+/-) mutation assay without metabolic activation for 24 h and found that TCS significantly induced mutation frequency. We further investigated the dose-response toxicity and genotoxicity of TCS. We combined the newly developed Pig-a gene mutation assay with bone marrow micronucleus (MN) test in a 19-day short-term study. ICR mice were administered orally with TCS at six dose levels from 0 to1000 mg/kg/day. We quantitatively assessed the dose-response relationships for the Pig-a assay, MN test, and organ coefficient data for possible points of departure (PoDs) by estimating the benchmark dose using PROAST software. We did not observe elevated Pig-a mutant frequency or MN frequency in TCS-treated mice. But a dose-dependent and statistically significant increase in liver organ coefficient data was observed. The PoD and acceptable daily intake based on organ toxicity were further developed and no greater than 1.82 and 0.00182 mg/kg/day, respectively, indicating that the toxicity of TCS may has been underestimated in previous studies and greater attention should be paid to low-level TCS exposure.

Evaluation of 3,4,4,9-trichlorocarbanilide to zebrafish developmental toxicity based on transcriptomics analysis

Triclocarban (TCC), considered an endocrine-disrupting, persistent, and bioaccumulating organic matter, has attracted a great deal of attention for its pollution and health risks. However, studies on its toxicological mechanism, especially for embryo development are limited. This article explores the cardiac developmental toxicity induced in zebrafish embryos after exposure to different TCC concentrations. First, liquid chromatography-tandem mass spectrometry was used in detecting TCC in embryos in vivo after exposure to various TCC. Results showed that embryonic TCC content reached 9.23 ng after exposure to 300 μg/L TCC, the heart rates of the embryos markedly decreased, heart abnormalities significantly increased. In addition, obvious pericardial effusion was observed in the larvae. Through transcriptome sequencing, 200 differential gene expression (DGE) patterns were detected in the TCC (300 μg/L) experimental and control groups. The results of GO function analysis and KEGG pathway of DGE showed that aryl hydrocarbon receptor (AhR) activation and cyp-related genes (cyp1a, cyp1b1 and cyp1c) were significantly up-regulated. these affected the normal development of zebrafish embryonic heart, tissue edema, and hemorrhage. TCC exhibited strong cardiac teratogenic effects and developmental toxicity, which is partly related to AhR activation. Transcriptome-based results are helpful in precisely determining the risk of TCC exposure. The potential mechanism between TCC and AhR should be further investigated.

Fate and biodegradation characteristics of triclocarban in wastewater treatment plants and sewage sludge composting processes and risk assessment after entering the ecological environment

Triclocarban (TCC) has a high detection frequency in soil, rivers, sediments, and organisms, and its ecological risks have attracted substantial attention. In this study, we analyzed the fate of TCC in four wastewater treatment plants (WWTPs) in Zhengzhou, China, the biodegradation characteristics during the composting process, and the ecological risks of TCC when entering different environmental compartments. The concentration of TCC in the influent was 731.1-812.4 ng/L. More than 53.4% of TCC was biodegraded during the wastewater treatment process, and less than 2.5% was retained in the effluent. TCC was effectively removed through microbial degradation and sewage sludge absorption, and there were only minor differences in the different wastewater treatment processes. It is worth noting that more than 38% of TCC was enriched in sewage sludge (1430.1-1663.8 ng/g). The corresponding biodegradation rates of TCC were 65.7% and 82.8% in sewage sludge after 17 days of composting treatment with sawdust and straw as bulking agents, respectively. The estimated results showed that effluent discharge into the city rivers was safe. Composting could effectively degrade TCC and decrease the ecological risk of TCC when applied to sewage sludge.

Review of endocrine disruptors on male and female reproductive systems

Endocrine disruptors (EDs) interfere with different hormonal and metabolic processes and disrupt the development of organs and tissues, as well as the reproductive system. In toxicology research, various animal models have been utilized to compare and characterize the effects of EDs. We reviewed studies assessing the effect of ED exposure in humans, zebrafish, and mouse models and the adverse effects of EDs on male and female reproductive systems. This review outlines the distinctive morphological characteristics, as well as gene expression, factors, and mechanisms that are known to occur in response to EDs. In each animal model, disturbances in the reproductive system were associated with certain factors of apoptosis, the hypothalamic-pituitary-gonadal axis, estrogen receptor pathway-induced meiotic disruption, and steroidogenesis. The effects of bisphenol A, phthalate, and 17α-ethinylestradiol have been investigated in animal models, each providing supporting outcomes and elaborating the key regulators of male and female reproductive systems.

Contribution of Time, Taxonomy, and Selective Antimicrobials to Antibiotic and Multidrug Resistance in Wastewater Bacteria

The use of nontherapeutic broad-spectrum antimicrobial agents triclosan (TCS) and benzalkonium chloride (BC) can contribute to bacterial resistance to clinically relevant antibiotics. Antimicrobial-resistant bacteria within wastewater may reflect the resistance burden within the human microbiome, as antibiotics and pathogens in wastewater can track with clinically relevant parameters during perturbations to the community. In this study, we monitored culturable and resistant wastewater bacteria and cross-resistance to clinically relevant antibiotics to gauge the impact of each antimicrobial and identify factors influencing cross-resistance profiles. Bacteria resistant to TCS and BC were isolated from wastewater influent over 21 months, and cross-resistance, taxonomy, and monthly changes were characterized under both antimicrobial selection regimes. Cross-resistance profiles from each antimicrobial differed within and between taxa. BC-isolated bacteria had a significantly higher prevalence of resistance to "last-resort antibiotic" colistin, while isolates resistant to TCS exhibited higher rates of multidrug resistance. Prevalence of culturable TCS-resistant bacteria decreased over time following Food and Drug Administration (FDA) TCS bans. Cross-resistance patterns varied according to sampling date, including among the most clinically important antibiotics. Correlations between strain-specific resistance profiles were largely influenced by taxonomy, with some variations associated with sampling date. The results reveal that time, taxonomy, and selection by TCS and BC impact features of cross-resistance patterns among diverse wastewater microorganisms, which could reflect the variety of factors influencing resistance patterns relevant to a community microbiome.

The fate of triclocarban in activated sludge and its influence on biological wastewater treatment system

Triclocarban (TCC), a typical emerging contaminant, was abundantly released into environment and frequently detected in practical wastewater treatment plants. However it is also an important material when being added to personal skin care products as a antibacterial agent. In this work, the behavior of TCC in wastewater treatment process was investigated. Experiments showed that ~82% of influent TCC was removed by activated sludge adsorption and its adsorption isotherm was well fitted with Linear model and Freundich model. High levels of TCC had seriously impact on the settleability, dewaterability and extracellular polymetric substance (EPS) of activated sludge, even on effluent turbidity after a long-term exposure. Furthermore, the performance of biological wastewater treatment was damaged by TCC long-term exposure as well. The removal rates of total nitrogen and phosphorus decreased from 91.2 ± 2.1% to 72.6 ± 2.2% and from 94.7 ± 3.1% to 78.4 ± 2.3%, respectively, with TCC level increasing from 0 to 100 μg/L. Mechanism analysis showed that TCC exposure significantly inhibited the relevant biological processes, such as ammonia oxidation, denitrification, phosphorus release and uptake, which were closely relevant to nitrogen and phosphorus removal.

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.

Characterization of triclosan and triclocarban in indoor dust from home micro-environments in Vietnam and relevance of non-dietary exposure

Contamination status, spatial variability, and exposure risk of triclosan (TCS) and triclocarban (TCC) in indoor dusts from different micro-environments were evaluated for the first time in Vietnam as well as in Southeast Asian region. TCS and TCC were measured in 89 dust samples collected from bedrooms, living rooms, and kitchens of private houses in four northern cities including Hanoi, Bac Ninh, Hung Yen, and Nam Dinh, by means of liquid chromatography-tandem mass spectrometry. Concentrations of TCS and TCC ranged from <5 to 1090 (median 33.2) and from <3 to 531 (median 19.3) ng g^-1, respectively. Concentrations of TCS and TCC in the kitchen and bedroom dusts were markedly higher than levels found in the living room samples, probably due to their applications in kitchen utensils, household cleaning reagents, and personal care products. A strong positive correlation between TCS and TCC concentrations was detected in the whole dataset (R² = 0.810, p < 0.001). For samples in which both TCS and TCC were quantified, TCS/TCC ratios ranged from 0.3 to 12 with a median value of 1.8, and did not show big differences between micro-environments. Human exposures to TCS and TCC through dust ingestion were estimated for various age groups with 95% CI daily intake doses ranging from (0.032-0.070) to (0.340-0.740) and from (0.017-0.033) to (0.175-0.345) ng kg-bw^-1 d^-1 for adults and infants respectively. Although our derived values were much lower than reference doses, more comprehensive risk assessment considering multiple exposure pathways of TCS and TCC is needed.

Occurrence and mass loads of biocides in plastic debris from the Pearl River system, South China

Chemical pollution in the plastic debris is an increasing global concern as most pollutants might transfer from the environment to living organisms via plastic debris. In this study, biocides in the plastic debris floating on the surface water of the Pearl River system were investigated. The abundances of large plastic debris and microplastics in the surface water were 0.07 ± 0.13 and 0.94 ± 1.87 items/m³, respectively. Totally, 15 and 16 out of 19 biocides were detected in the large plastic debris and microplastics, with the concentration of each biocide in the ranges of 22.6-2460 ng/g and 16.9-2890 ng/g, respectively. Meanwhile, the concentration ranges of the detected biocides were 0.01-215 ng/L in surface water. Triclosan, triclocarban, methylparaben, and N,N-diethyl-3-methylbenzamide (DEET) were the frequently detected compounds in the plastic samples and surface water. The partition coefficients (K_d) of biocides between the plastic debris and surface water showed a weak positive correlation with K_ow values. Biocides were also detected on the natural floats (tree leaves and branches) at concentrations of 13.7-786 ng/g. The annual mass load of biocides in plastic debris at each site was up to 265 g/y, thereby suggesting that plastic debris might be an important carrier for the emerging contaminants, such as biocides.

Fate, risk and removal of triclocarban: A critical review

The halogenated antimicrobial triclocarban (TCC) has large production and consumption over last decades. Its extensive utilization in personal care products and insufficient treatment in conventional wastewater treatment plants (WWTPs) has led to its listing as one of emerging organic contaminants (EOCs). Due to the hydrophobicity and chemical stability of TCC, it has been omnipresent detected in terrestrial and aquatic environments, and its prolonged exposure has thrown potential pernicious threat to ecosystem and human health. Considering its recalcitrance, especially under anoxic conditions, both biological and non-biological methods have been exploited for its removal. The efficiency of advanced oxidation processes was optimistic, but complete removal can rarely be realized through a single method. The biodegradation of TCC either with microbial community or pure culture is feasible but efficient bacterial degraders and the molecular mechanism of degradation need to be further explored. This review provides comprehensive information of the occurrence, potential ecological and health effects, and biological and non-biological removal of TCC, and outlines future prospects for the risk evaluation and enhanced bioremediation of TCC in various environments.

Occurrence and fate of antimicrobial triclocarban and its transformation products in municipal sludge during advanced anaerobic digestion using microwave pretreatment

This study, for the first time, investigated the impact of microwave pretreatment on the fate of the pervasive antimicrobial triclocarban (TCC) that was already present in municipal sludge, before and during advanced anaerobic digestion (AD) under thermophilic and mesophilic conditions. A range of microwave temperature (80 and 160 °C) and exposure duration (1 and 30 min) configurations were studied by employing ten bench-scale anaerobic digesters fed with mixed sludge at three different solids retention times (SRTs) including 20, 12, and 6 days. Seasonal changes influenced the levels of TCC in municipal sludge sampled from a plant employing the biological nutrient removal. Initial batch pretreatment studies showed that microwave irradiation itself can achieve TCC removal efficiencies up to 30 ± 4 and 64 ± 5% at 80 and 160 °C, respectively. The control digesters utilizing un-pretreated mixed sludge showed limited TCC removals, between 18 and 32% and 11-26% respectively, under thermophilic and mesophilic temperatures. On the other hand, the highest TCC elimination (78 ± 2%) was obtained from the thermophilic digester utilizing microwaved sludge at 160 °C for 30 min at SRT of 12 days. The non-chlorinated carbanilide (a transformation product of TCC) was detected and quantified for the first time during conventional and microwave-pretreated anaerobic sludge digestion. The formation of carbanilide in biosolids through reductive dechlorination could be an indicator of efficient and complete TCC transformation. This research demonstrated that AD coupled with microwave pretreatment can be used to reduce environmental concentrations of TCC in municipal sludge and biosolids.

Bioaugmentation of triclocarban and its dechlorinated congeners contaminated soil with functional degraders and the bacterial community response

Partial removal of haloaromatic antimicrobial triclocarban (TCC) during wastewater treatment caused the final introduction of residual TCC into soils. Bioaugmentation has been proposed for the biodegradation of TCC and its dechlorinated congeners 4,4'-dichlorocarbanilide (DCC) and carbanilide (NCC) in soil. The isolated TCC-degrading strain Ochrobactrum sp. TCC-2 and chloroanilines-degrading strain Diaphorobacter sp. LD72 were used to study the removal efficiency of TCC, DCC and NCC mixture and their chloroanilines intermediates, respectively. The potential degradation competition between TCC and its dechlorinated congeners, and the response of bacterial community during the bioremediation were also investigated. The biodegradation of DCC and TCC was significantly enhanced for soil with inoculums compared with sterilized and natural soils. Chloroanilines products could also be effectively removed. For the degradation of combined substrates in the aqueous medium, NCC had negative effect on the degradation of TCC and DCC, while TCC and DCC negatively influenced each other. The bioaugmentation with two degraders obviously changed the phylogenetic composition and function of indigenous soil microbiome. Importantly, the inoculated degraders could be maintained, suggesting their adaptability and potential application in bioaugmentation for such recalcitrant contaminants. This study offers new insights into the enhanced bioremediation of TCC and its dechlorinated congeners contaminated soils by the bioaugmentation of functional degraders and the structure and function response of the indigenous soil microbiome to the bioremediation process.

Occurrence, fate and risk assessment of biocides in wastewater treatment plants and aquatic environments in Thailand

This study investigated the occurrence and fate of 19 biocides in 8 wastewater treatment plants and receiving aquatic environments (both freshwater and estuarine systems) in Thailand. The predominant compound in wastewater and surface water was methylparaben with the maximum concentration of 15.2 μg/L detected in the receiving river, while in sludge and sediment was triclocarban with the maximum concentration of 8.47 μg/g in sludge. Triclosan was the main contaminants in the fish samples with the maximum concentration of 1.20 μg/g. Similar results of biocides were found in the estuarine system in Pattaya city, with the maximum concentration of 185 ng/L in sea water for methylparaben, and 242 ng/g in estuarine sediment for triclocarban. The aqueous removal rates for the biocides ranged from 15% to 95% in average. The back estimated-usage and total estimated emission of Ʃ19 biocides in Thailand was 279 and 202 tons/year, respectively. Preliminary ecological risk assessment showed that clotrimazole and triclosan could pose high risks to aquatic organisms in the receiving aquatic environments.

Study of aquatic life criteria and ecological risk assessment for triclocarban (TCC)

Triclocarban (TCC) is used as a broad-spectrum antimicrobial agent, the intensive detection of TCC in aquatic environments and its potential risks to aquatic organisms are concerned worldwide. In this study, 8 Chinese resident aquatic organisms from 3 phyla and 8 families were used for the toxicity tests, and four methods were employed to derive the aquatic life criteria (ALC). A criterion maximum concentration (CMC) of 1.46 μg/L and a criterion continuous concentration (CCC) of 0.21 μg/L were derived according to the USEPA guidelines. The acute predicted no effect concentrations (PNECs) derived by species sensitivity distribution (SSD) methods based on log-normal, log-logistic and Burr Type Ⅲ models were 2.64, 1.88 and 3.09 μg/L, respectively. The comparisons of ALCs derived with resident and non-resident species showed that the CMC and CCC of TCC derived with Chinese resident species could provide a sufficient protection for non-resident species. The higher toxicity of TCC on aquatic organisms was found compared with other antimicrobial agents (except for Clotrimazole) in aquatic environment. The strong positive linear correlation was observed between the TCC and TCS concentrations in aquatic environment with a correlation coefficient (R²) of 0.8104, it is of great significance in environmental monitoring and risk assessment for TCC and TCS. Finally, the ecological risk assessment showed that the TCC in Yellow River basin and Pearl River basin had higher risk with the mean potential affected fractions (PAFs) of 9.27% and 7.09%, and 22.10% and 15.00% waters may pose potential risk for 5% aquatic organisms, respectively. In general, the risk of TCC in Asian waters was higher than that in Europe and North America.

Contamination and spatial distribution of parabens, their metabolites and antimicrobials in sediment from Korean coastal waters

Synthetic antimicrobials known as parabens, triclosan (TCS), and triclocarban (TCC) are emerging environmental contaminants. Limited studies on these contaminants have been conducted in coastal environments. In our study, parabens, their metabolites, TCS, and TCC were measured in sediment collected along the Korean coast, to investigate contamination status, spatial distribution, and potential health risks to coastal environments. Methyl paraben and 4-hydroxybenzoic acid were detected in all sediment samples, suggesting widespread contamination. Total concentrations of parent parabens, their metabolites, TCS, and TCC ranged from 0.19 to 11.2 (mean: 2.40) ng/g dry weight, 9.65 to 480 (mean: 120) ng/g dry weight, and < limit of quantification (LOQ)-6.10 (mean: 0.41) ng/g dry weight, and from < LOQ-41.0 (mean: 2.78) ng/g dry weight, respectively. The overall contamination of parabens and antimicrobials in sediment was different from that reported for persistent organic pollutants due to different contamination sources among chemical groups. Significant correlation was found among target contaminants in sediment, suggesting the existence of a common source. Total organic carbon (TOC) was significantly correlated with the concentrations of target contaminants, implying a major factor for coastal distribution of parabens and antimicrobials. The concentrations of parabens and TCS measured in sediment did not exceed a hazard quotient (HQ), implying low potential health risks associated with exposure to these contaminants. This is the first study to report the nationwide distribution of parabens, their metabolites, and antimicrobials in the coastal environments of Korea.

Deriving aquatic life criteria for galaxolide (HHCB) and ecological risk assessment

The polycyclic musk galaxolide (HHCB) is widely used as fragrances in personal care products (PCPs) and has been detected in various environmental media. There is an urgent need to derive aquatic life criteria (ALC) of HHCB for the protection of aquatic organisms. Toxicity tests with 8 Chinese resident aquatic organisms from 3 phyla and 8 families were conducted, and three methods were used for deriving the ALC. A criterion maximum concentration (CMC) of 8.33 μg/L and a criterion continuous concentration (CCC) of 2.20 μg/L were derived according to the USEPA guidelines. The acute predicted no effect concentrations (PNECs) values derived by log-normal species sensitivity distribution (SSD) and log-logistic SSD method were 77.41 and 66.47 μg/L, respectively. In addition, a significant sensitivity difference was observed between the planktonic crustacean and benthic crustacean, and there was no significant difference (p > 0.05) among SSDs based on resident and non-resident species. A comparison of chronic SSDs between HHCB, tonalide (AHTN) and musk ketone (MK) showed that nitro musk (MK) was more toxic to aquatic organisms than polycyclic musks (HHCB and AHTN). Finally, an assessment of risk to aquatic organisms in surface waters and effluents of wastewater treatment plants (WWTPs) worldwide showed that potential risk may exist at several locations. HHCB concentrations in 4.08 and 46.17% of the WWTP effluents in China and 1.71 and 16.13% of the WWTP effluents in other countries exceed the hazard concentration for 5% and 1% aquatic species.

Fate of Triclocarban (TCC) in aquatic and terrestrial systems and human exposure

Triclocarban (TCC) is considered as contaminant of emerging concern (CEC), and ranked in the top 10 CEC occurrence. TCC is a high production volume synthetic chemical used extensively in various personal care products. This chemical will be released into the environment via incomplete wastewater treatment and untreated wastewater discharge. TCC and its transformation products (4,4'-dichlorocarbilide (DCC),1-(3-chlorophenyl)-3-phenylurea (MCC) and carbanilide (NCC),2'OH-TCC, 3'OH-TCC) were detected in the environmental matrices. Sediment organic carbon will influence TCC concentrations in suspended and bed sediments. TCC is an antimicrobial agent and also emerging endocrine disruptor that can cause immune dysfunction and affect human reproductive outcomes. Furthermore, TCC alters the expression of proteins related to binding and metabolism, skeletal muscle development and function, nervous system development and immune response. TCC has potential health risks in wildlife and humans. Several animal studies illustrate that it can cause various adverse effects, which can be monitored by antioxidant biomarkers (CAT, GST and LPO). Accumulation of TCC in organisms depends on the lipophilicity and bioavailability of TCC in sediment and water. TCC was continuously detected in aquatic system. TCC is a lipophilic compound, which can efficiently bind with lipid content. Women are more vulnerable to TCC due to substantially higher frequency and extended exposure to TCC. This review provides basic information of occurrence of TCC and the exposure levels in aquatic organisms. Several literature have shown the higher usage and human exposure levels of TCC, which provides useful information for the chemical management approaches.

Occurrence, seasonal variation and risk evaluation of selected endocrine disrupting compounds and their transformation products in Jiulong river and estuary, China

In the present study, 13 endocrine disrupting compounds (EDCs) and their transformation products (TPs) were monitored in Jiulong River and its estuary, China in different seasons. The analytes included antimicrobials [triclosan (TCS) and triclocarbon (TCC)]; estrogens [estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2)]; alkylphenol ethoxylates [4-n-nonylphenol (NP) and 4-n-octylphenol (OP)] and the TPs [methyl triclosan (MeTCS), carbanilide (NCC), dichlorocarbanilide, 4-hydroxy estrone (4-OH E1) and 4-hydroxy estradiol (4-OH E2)]. A significant seasonal variation was observed for most EDCs. Approximately, 79% of the total E2 residues were detected in the normal season in comparison with the wet season to indicate recalcitrant behavior of E2 during the normal season. Risk assessment revealed that E2 was most potent among the EDCs to cause highest risk to both vertebrate and invertebrate aquatic species, whereas, E1, EE2, MeTCS and TCS also showed relatively high risk for some surface water aquatic species.

Bioaccumulation of endocrine disrupting compounds in fish with different feeding habits along the largest subtropical river, China

Endocrine disrupting compounds (EDCs) are becoming an increasing concern regarding bioaccumulation in aquatic biota. However, the effects of regional pollution levels and specific feeding habits on the bioaccumulation of EDCs in fish are rarely reported. 4-Nonylphenol (4-NP), bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), triclocarban (TCC) and triclosan (TCS) were determined in abiotic compartments [water, sediment, suspended particulate matter (SPM)] and fish with different feeding habits along the Pearl River, China. EDCs in abiotic compartments exhibited significant (p < 0.05) spatial variations, forming five zones clustered based on site-specific EDC concentrations. 4-NP was the dominant compound, contributing 58-98% of the EDCs in fish, followed by BPA (<41%), 4-t-OP (<13%), and TCC and TCS (<4.7%). The concentrations of 4-NP and 4-t-OP, BPA, and TCC and TCS were the highest in brackish carnivorous, planktivorous, and detritivorous fish, respectively. The bioaccumulation factors (BAFs) showed that 4-NP accumulated (BAF > 5000) in all fish except for suck-feeding detritivores, while 4-t-OP and TCC accumulated in filter-feeding planktivores. The concentration of 4-NP in carnivores was significantly higher than that in detritivores, indicating the potential biomagnification of 4-NP along food chains. EDCs in sediment and SPM and those in water were most positively correlated with those in detritivores and planktivores, respectively, suggesting the potential of fish with these two feeding habits to act as bioindicators of EDC pollutants.

Nationwide reconnaissance of five parabens, triclosan, triclocarban and its transformation products in sewage sludge from China

China's rapid growth of both population size and sanitation infrastructure have created a heightened need for responsible management of sewage sludge. We applied liquid chromatography in conjunction with isotope dilution tandem mass spectrometry to measure multiple endocrine disrupting antimicrobials and their transformation products in 100 sewage sludge samples collected across 21 Chinese provinces/districts. Occurrences (detection frequencies) and concentrations (ng/g dry weight) were as follows: triclosan (99%; <4-4870), triclocarban (95%; <3-43,300), 2'-hydroxy-triclocarban (94%; <1-2340), 3'-hydroxy-triclocarban (91%; <1-1250), 3,3',4,4'-tetrachlorocarbanilide (100%; 22-580), dichlorocarbanilide (94%; <2-23,890), monocarbanilide (92%; <2-120), carbanilide (90%; <3-1,340), and five parabens: methyl- (98%; <2-630), ethyl- (96%; <2-170), propyl- (99%; <2-27), butyl- (89%; <2-11) and benzyl-paraben (7%; <2-12). The transformation products of triclocarban were measured for the first time in Chinese wastewater system, and ratios of transformation products to parental triclocarban indicate ongoing triclocarban dechlorination during wastewater treatment. Contaminant profiles and concentrations differed by region, treatment capacity, and wastewater type. Extrapolation of collected data yielded an estimate for the total mass of 13 analytes sequestered in Chinese sewage sludge of 68 t/y with an upper bound of 400 t/y. This China-wide survey established baseline levels of selected antimicrobials in sludges whose current disposal is performed with little regulatory oversight and enforcement.

Pentafluorosulfanyl-containing Triclocarban Analogs with Potent Antimicrobial Activity

Concerns have been raised about the long-term accumulating effects of triclocarban, a polychlorinated diarylurea widely used as an antibacterial soap additive, in the environment and in human beings. Indeed, the Food and Drug Administration has recently banned it from personal care products. Herein, we report the synthesis, antibacterial activity and cytotoxicity of novel N,N′-diarylureas as triclocarban analogs, designed by reducing one or more chlorine atoms of the former and/or replacing them by the novel pentafluorosulfanyl group, a new bioisostere of the trifluoromethyl group, with growing importance in drug discovery. Interestingly, some of these pentafluorosulfanyl-bearing ureas exhibited high potency, broad spectrum of antimicrobial activity against Gram-positive bacterial pathogens, and high selectivity index, while displaying a lower spontaneous mutation frequency than triclocarban. Some lines of evidence suggest a bactericidal mode of action for this family of compounds.

An evaluation on the intra-day dynamics, seasonal variations and removal of selected pharmaceuticals and personal care products from urban wastewater treatment plants

Pharmaceuticals and personal care products (PPCPs) in wastewater have become an emerging issue due to their negative effects on human health and aquatic ecosystems. Two full-scale municipal and industrial wastewater treatment plants (WWTPs) along the Songhua River were chosen to evaluate the intra-day dynamics, seasonal variations and removal of 12 selected PPCPs. Our results suggested that the selected PPCPs were frequently detected in the influent and effluent. Caffeine was the predominant compound in the influent; while the selected PPCPs was dominated by TCS in the effluent, suggesting the different fates of selected PPCPs in the WWTPs. The intra-day dynamics of PPCPs in the influent were evaluated, suggesting that the 12 PPCPs can be grouped into three categories because of their different use patterns. The analysis of seasonal changes of PPCPs concentrations in the WWTPs suggested that the concentrations of some PPCPs were influenced by the chemical usage, degradation and temperature. The removal efficiency for the PPCPs were very high with the values ranged from 70.0% to 99.7% for WWTP#1, and from 62.5% to 99.4% for WWTP#2. Significant seasonal variations of PPCPs removal efficiency were observed. Base on the mass loading of PPCPs in the two WWTPs, our results suggested that WWTP#1 in the urban core received much more PPCPs in comparison to WWTP#2 in the suburban regions, suggesting that influences of the service population.

Assessment of human exposure to triclocarban, triclosan and five parabens in U.S. indoor dust using dispersive solid phase extraction followed by liquid chromatography tandem mass spectrometry

Antimicrobials in indoor dust pose concerns due to their endocrine disrupting activities and potential promotion of antibiotic resistance. We adopted dispersive solid phase extraction (d-SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify antimicrobials in dust. The method showed favorable linearity (R² >0.99), recovery (83-115%), and method detection limits (1.2-5.6 ng/g, dry weight). All seven analytes were found at median concentrations in ng/g in each of the 80 U.S. dust samples collected from athletic facilities and residential homes: methyl paraben (1920) > propyl paraben (965) > triclosan (390) > triclocarban (270) > ethyl paraben (195) > butyl paraben (80) > benzyl paraben (6). Triclosan levels in dust from athletic facilities were significantly higher than those in private homes (p < 0.05). Median estimated daily intake (EDI) of antimicrobials in ng/kg-body weight/d from dust ingestion was lowest for adults (1.9) and higher for more sensitive subpopulations, including infants (19.8), toddlers (23.6), children (11.8) and teenagers (4.6). This first application of d-SPE to the analysis of dust produced U.S. baseline data for triclosan and triclocarban levels in indoor dust just prior to the 2017 Federal ban on use of these trichlorinated aromatics in antiseptic soaps and related personal care products.

Contamination and risk profiles of triclosan and triclocarban in sediments from a less urbanized region in China

Triclosan and triclocarban are priority environmental contaminants of increasing concern to environmental health. After application, the chemicals enter the aquatic environment and easily distribute in bed sediment due to their hydrophobicity, and thus pose potential ecological risks. This study investigated the distribution and risks of triclosan and triclocarban in the sediment environment of a less urbanized region in South China. The sampling sites with high levels of triclosan and triclocarban were found to locate in the tributaries. When compared to other monitoring results obtained from more densely populated regions, the residues of triclosan and triclocarban in the investigated region were low, suggesting that these two chemicals conservation in sediment is related to anthropic activities. The results of risk quotients showed that high risks to aquatic organisms were posed by triclosan residues in sediment, while the risks to benthic organisms were quite low. Triclocarban residues in sediment posed minimal to medium risks to aquatic and benthic organisms. In summary, using either of the calculation methods of risk quotients, medium risks posed by the antimicrobials can be found in certain sampling sites with low population densities. The results may be useful in the development of evidence-based policies for the government.

Occurrence of triclocarban and benzotriazole ultraviolet stabilizers in water, sediment, and fish from Indian rivers

Triclocarban and benzotriazole ultraviolet stabilizers (BUVSs) are listed as high production volume synthetic chemicals, used extensively in personal care products. Many of these chemicals persist in the aquatic environment as micropollutants. Knowledge on their fate in freshwater ecosystems is still lacking, especially in the Indian Rivers. Our intention is to study the seasonal distribution, hazard quotient, risk assessment, and bioaccumulation of triclocarban and BUVSs (UV-9, UV-P, UV-326, UV-327, UV-328, and UV-329) during wet and dry seasons in water, sediment and fish from the Kaveri, Vellar, and Thamiraparani rivers in Tamil Nadu State, India. Triclocarban and BUVSs were identified in all matrices analysed. Triclocarban was found in water, sediment, and fish up to 1119ng/L, 26.3ng/g (dry wt.), and 692ng/g (wet wt.), respectively. Among BUVSs, UV-329 was found up to 31.3ng/L (water samples), UV-327 up to 7.3ng/g (sediment samples), and UV-9 up to 79.4ng/g (fish samples). The hazard quotient (HQ_env.) for triclocarban in surface water was found to be at risk level (HQ_env. >1) in the Kaveri, and Thamiraparani rivers during dry season. Bioaccumulation factors indicate that target compounds (triclocarban and BUVSs) could bio-accumulate in organisms.

Personal care products in wild fish in two main Chinese rivers: Bioaccumulation potential and human health risks

Personal care products (PCPs) are widely applied in our daily life, however, little is known about their occurrence in wild fish. We investigated the bioaccumulation and potential risks of 24 PCPs in muscle and liver tissues of wild fish collected from two large rivers of Pearl and Yangtze Rivers in China. The results showed the detection of a total of 13 PCPs including 9 biocides, 2 synthetic musks and 2 benzotriazoles in at least one type of fish tissue from 12 fish species. The compounds with high detection frequencies (>50%) in fish muscle or liver tissues were N,N-diethyl-3-methylbenzamide, carbendazim, climbazole, miconazole (MCZ), methylparaben, propylparaben, triclosan (TCS), tonalide, galaxolide (HHCB) and 5-methyl-1H-benzotriazole (5-TT). Among biocides, synthetic musks and benzotriazoles, TCS, HHCB and benzotriazole showed the maximum concentrations of 79.5ng/g wet weight (ww), 299ng/g ww and 3.14ng/g ww, respectively, in muscle tissue, while MCZ, HHCB and 5-TT showed the maximum concentrations of 432ng/g ww, 2619ng/g ww and 54.5ng/g ww, respectively, in liver tissue. The median values of logarithm of bioaccumulation factors (BAF) for the detected 13 PCPs were ranged 0.8-3.35 in muscle and 0.85-4.58 in liver. The log BAF values of the PCPs displayed good linear relationships with log K_ow and log D_ow (pH-dependent K_ow). The health hazard assessment of 10 detected PCPs in the muscle indicated no appreciable risk to human via consumption of the wild fish.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

Distribution of six anticancer drugs and a variety of other pharmaceuticals, and their sorption onto sediments, in an urban Japanese river

The distributions of 31 pharmaceuticals grouped into nine therapeutic classes, including six anticancer drugs, were investigated in the waters and sediments of an urban river in Japan. The coefficients of sorption (logK _d) to the river sediments were also determined from the results of a field survey and laboratory-scale experiment. Three anticancer drugs-bicalutamide, doxifluridine, and tamoxifen-were detected in the river sediments at maximum concentrations of 391, 392, and 250 ng/kg, respectively. In addition, the transformation products of psychotropic carbamazepine (2-hydroxy carbamazepine, acridine, and acridone) were detected in the range of 108 ng/kg (2-hydroxy carbamazepine) to 2365 ng/kg (acridine), and the phytoestrogen glycitein was detected in the range of N.D. to 821 ng/kg. The logK _d values of the targeted pharmaceuticals in river sediments in the field survey ranged from 0.5 (theophylline) to 3.3 (azithromycin). These results were in accord with those of the laboratory-scale sorption experiment. To the best of our knowledge, this is the first report of the detection of the anticancer drugs bicalutamide and tamoxifen, the transformation products of carbamazepine (2-hydroxy carbamazepine, acridine, and acridone), and the phytoestrogen genistein in river sediments.

The Florence Statement on Triclosan and Triclocarban

The Florence Statement on Triclosan and Triclocarban documents a consensus of more than 200 scientists and medical professionals on the hazards of and lack of demonstrated benefit from common uses of triclosan and triclocarban. These chemicals may be used in thousands of personal care and consumer products as well as in building materials. Based on extensive peer-reviewed research, this statement concludes that triclosan and triclocarban are environmentally persistent endocrine disruptors that bioaccumulate in and are toxic to aquatic and other organisms. Evidence of other hazards to humans and ecosystems from triclosan and triclocarban is presented along with recommendations intended to prevent future harm from triclosan, triclocarban, and antimicrobial substances with similar properties and effects. Because antimicrobials can have unintended adverse health and environmental impacts, they should only be used when they provide an evidence-based health benefit. Greater transparency is needed in product formulations, and before an antimicrobial is incorporated into a product, the long-term health and ecological impacts should be evaluated. https://doi.org/10.1289/EHP1788.

Influence of thermal hydrolysis-anaerobic digestion treatment of wastewater solids on concentrations of triclosan, triclocarban, and their transformation products in biosolids

The growing concern worldwide regarding the presence of emerging contaminants in biosolids calls for a better understanding of how different treatment technologies at water resource recovery facilities (WRRFs) can influence concentrations prior to biosolids land application. This study focuses on the influence of solids treatment via the Cambi Thermal Hydrolysis Process™ in conjunction with anaerobic digestion (TH-AD) on concentrations of triclosan (TCS), triclocarban (TCC), and their transformation products in biosolids and sludges. Concentrations of the target analytes in biosolids from the TH-AD process (Class A), sludges from the individual TH-AD treatment steps, and limed biosolids (Class B) from the same WRRF were compared. TCC concentrations were significantly lower in Class A biosolids than those in the Class B product - a removal that occurred during thermal hydrolysis. Concentrations of TCS, methyl triclosan, and 2,4-dichlorophenol, conversely, increased during anaerobic digestion, leading to significantly higher concentrations of these compounds in Class A biosolids when compared to Class B biosolids. Implementation of the TH-AD process had mixed effect on contaminant concentrations.

Persistence, temporal and spatial profiles of ultraviolet absorbents and phenolic personal care products in riverine and estuarine sediment of the Pearl River catchment, China

A variety of personal care products have been classified as emerging contaminants (ECs). Occurrence, fate, spatial and vertical profiles of 13 ultraviolet absorbents, triclocarban (TCC) and its dechlorinated products, triclosan (TCS), 2-phenylphenol and parabens were investigated in riverine and estuarine sediment of the Pearl River catchment, China. Bisphenol A (BPA), a widely applied plasticizer, was also investigated. The ECs were widely present in the bed sediment. TCC was the most abundant with a maximum concentration of 332ngg^-1 dry weight. The other prominent ECs included BPA, TCS, octocrylene, and benzotriazole UV stabilizers UV326 and UV328. Treated wastewater effluent was the major source of the ECs in the riverine sediment. TCC, BPA, TCS, methyparaben, UV531, UV326, and UV328 were also detected throughout the estuarine sediment cores, indicating their persistence in the sediment. Temporal trends of the ECs in the sediment cores reflected a combined effect of industrial development, population growth, human life quality improvement, and waste treatment capacity in the Pearl River Delta over the last decades. TCC dechlorination products were frequently detected in the bed sediment with higher levels near treated effluent outlets but only occasionally observed in the sediment cores, suggesting insignificant in-situ TCC dechlorination in the sediment.

Functional Characterization of a Novel Amidase Involved in Biotransformation of Triclocarban and its Dehalogenated Congeners in Ochrobactrum sp. TCC-2

Haloaromatic antimicrobial triclocarban (3,4,4'-trichlorocarbanilide, TCC) is a refractory contaminant which is frequently detected in various aquatic and sediment environments globally. However, few TCC-degrading communities or pure cultures have been documented, and functional enzymes involved in TCC biodegradation hitherto have not yet been characterized. In this study, a bacterial strain, Ochrobactrum sp. TCC-2, capable of degrading TCC under both aerobic and anaerobic conditions was isolated from a sediment sample. A novel amidase gene (tccA), responsible for the hydrolysis of the two amide bonds of TCC and its dehalogenated congeners 4,4'-dichlorocarbanilide (DCC) and carbanilide (NCC) to more biodegradable chloroaniline or aniline products, was cloned and characterized. TccA shares low amino acid sequence identity (27 to 38%) with other biochemically characterized amidases and contains the conserved catalytic triad (Ser-Ser-Lys) of the amidase signature enzyme family. TccA was stable over a pH range of 5.0 to 10.0 and at temperatures lower than 60 °C, and it was constitutively expressed in strain TCC-2. In contrast to the halogenated TCC and DCC, the nonchlorinated NCC was the preferred substrate for TccA. TccA also had hydrolysis activity to a broad spectrum of amide bonds in herbicides, insecticides, and chemical intermediates. The constitutive expression and broad substrate spectrum of TccA suggested strain TCC-2 may be potentially useful for bioremediation applications.

Chronic effects of triclocarban in the amphipod Gammarus locusta: Behavioural and biochemical impairment

Triclocarban (TCC), a common antimicrobial agent widely used in many household and personal care products, has been widely detected in aquatic ecosystems worldwide. Due to its high lipophilicity and persistence in the aquatic ecosystems, TCC is of emerging environmental concern. Despite the frequently reported detection of TCC in the environment and significant uncertainties about its long term effects on aquatic ecosystems, few studies have addressed the chronic effects of TCC in aquatic organisms at ecologically relevant concentrations. Therefore, we aimed at testing a broad range of biological responses in the amphipod Gammarus locusta following a chronic (60 days) exposure to environmentally relevant concentrations of TCC (100, 500 and 2500ng/L). This work integrated biochemical markers of oxidative stress (catalase (CAT), glutathione-s-transferase (GST) and lipid peroxidation (LPO)) and neurotransmission (acetylcholinesterase (AChE)) with several key ecological endpoints, i.e. behaviour, survival, individual growth and reproduction. Significant alterations were observed in all biochemical markers. While AChE showed a dose-response curve (with a significant increased activity at a TCC concentration of 2500ng/L), oxidative stress markers did not follow a dose-response curve, with significant increase at 100 and/or 500ng/L and a decreased activity in the highest concentration (2500ng/L). The same effect was observed in the females' behavioural response, whereas males' behaviour was not affected by TCC exposure. The present study represents a first approach to characterize the hazard of TCC to crustaceans.

Rhamnolipid-enhanced aerobic biodegradation of triclosan (TCS) by indigenous microorganisms in water-sediment systems

Bioremediation of triclosan (TCS) is a challenge because of its low bioavailability, persistence in the environment and recalcitrance to remediation efforts. Rhamnolipid (RL) was used to enhance TCS biodegradation by indigenous microbes in an aerobic water-sediment system. However, knowledge of the effects of TCS on the bacterial community and environmental factors in an RL-enhanced, TCS-degrading system are lacking. Therefore, in this study, the influence of environmental factors on RL-enhanced biodegradation of TCS was investigated by single factor experiments, and shifts in aerobic TCS-degrading bacterial populations, with and without RL, were analyzed by high-throughput sequencing technology. The results showed that aerobic biodegradation of TCS was significantly promoted by the addition of RL. Environmental conditions, which included RL addition (0.125-0.5g/L), medium concentrations of TCS (<90μg/g), water disturbance, elevated temperature, ionic strength (0.001-0.1mol/L NaCl) and weak alkaline environments (pH8-9), were monitored. High concentrations of TCS had a remarkable influence on the bacterial community structure, and this influence on the distribution proportion of the main microorganisms was strengthened by RL addition. Alpha-proteobacteria (e.g., Sphingomonadaceae and Caulobacteraceae) might be resistant to TCS or even capable of TCS biodegradation, while Sphingobacteria, Beta- and Delta-proteobacteria were sensitive to TCS toxicity. This research provides ecological information on the degradation efficiency and bacterial community stability in RL-enhanced bioremediation of TCS-polluted aquatic environments.

Insights into reductive dechlorination of triclocarban in river sediments: Field measurements and in vitro mechanism investigations

Triclocarban (TCC) reductive dechlorination was investigated using a combination of field and laboratory experiments. Field monitoring revealed that TCC reductive dechlorination in river sediments leads to formation of two isomers of its lesser chlorinated congener namely 3,4'-dichlorocarbanilide and 4,4'-dichlorocarbanilide. Monochlorocarbanilide was not detected in sediments supporting that transformation of dichlorocarbanilide into monochlorocarbanilide is the rate limiting step of TCC dechlorination. In vitro experiments were conducted to study TCC potential reductive dechlorination mechanisms. These experiments demonstrated that 4,4'-dichlorocarbanilide was specifically formed upon a nucleophilic addition reaction under anaerobic conditions. The 3,4'-diclorocarbanilide was formed upon a two steps radical mechanism under aerobic conditions which includes TCC activation by one electron oxidation followed by a nucleophilic substitution reaction with glutathione. In vitro results suggested that strict anaerobic conditions might not be required for TCC reductive dechlorination in the environment. Moreover, in vitro reactions were performed using biomimetic or enzymatic systems supposing that TCC dechlorination might occur through microbial action in situ. Measured dichlorocarbanilide isomers/triclocarban ratios were used to evaluate the relative significance of both dechlorination pathways and the pathway leading to 3,4'-dichlorocarbanilide was found significant in all investigated river sediment samples.