Search

To investigate the antibacterial effect and the effect on the material properties of a novel delivery system with Irgasan as active agent and methacrylated polymerizable Irgasan when added to experimental dental resin composites.A delivery system based on novel polymeric hollow beads, loaded with Irgasan and methacrylated polymerizable Irgasan as active agents were used to manufacture three commonly formulated experimental resin composites. The non-modified resin was used as standard (ST). Material A contained the delivery system providing 4 % (m/m) Irgasan, material B contained 4 % (m/m) methacrylated Irgasan and material C 8 % (m/m) methacrylated Irgasan. Flexural strength (FS), flexural modulus (FM), water sorption (WS), solubility (SL), surface roughness Ra, polymerization shrinkage, contact angle Θ, total surface free energy γS and its apolar γS (LW), polar γS (AB), Lewis acid γS (+)and base γS (-) term as well as bacterial viability were determined. Significance was p0.05.The materials A to C were not unacceptably influenced by the modifications and achieved the minimum values for FS, WS and SL as requested by EN ISO 4049 and did not differ from ST what was also found for Ra. Only A had lower FM than ST. Θ of A and C was higher and γS (AB) of A and B was lower than of ST. Materials A to C had higher γS (+) than ST. The antibacterial effect of materials A to C was significantly increased when compared with ST meaning that significantly less vital cells were found.Dental resin composites with small quantities of a novel antibacterially doped delivery system or with an antibacterial monomer provided acceptable physical properties and good antibacterial effectiveness. The sorption material being part of the delivery system can be used as a vehicle for any other active agent.

Due to the rapid increase of carbon nanotubes (CNT) applications and their inevitable release into the aquatic environment, CNT may interact with and further influence the fate and transport of other pollutants such as triclocarban (TCC). TCC is a high-production-volume chemical that is widely used as an antimicrobial agent, is continually released into the aquatic environment, and is biologically active and persistent. In the present study, the population test with Daphnia magna was performed over 93 days. Different treatments were examined: (a) control, (b) solvent control, (c) 1 mg CNT/L from the beginning, (d) 1 mg CNT/L as of day 14, (e) control with a 2-day pulse of 25 µg TCC/L on day 14, 41 µg TCC/L (day 54), and 61 µg TCC/L (day 68) and (f) same pulses of TCC with co-exposure to 1 mg CNT/L. Significant changes in all three size classes were observed as a result of the long-term exposure to 1 mg CNT/L. Increasing in number of neonates, and decreasing in number of juveniles and adults were observed. Moreover, daphnids were significantly smaller when they were exposed to MWCNT. The exposure with TCC led to size-dependent mortality in Daphnia magna populations and a subsequent recovery. Lower toxicity of TCC was observed, with the presence of MWCNT in the medium. The reported effects of TCC on population level were compared to the output of an individual-based Daphnia magna population model, in order to verify the model predictions with laboratory data.

This study describes the use of cork as a new coating for bar adsorptive microextraction (BAμE) and its application in determining benzophenone, triclocarban and parabens in aqueous samples by HPLC-DAD. In this study bars with 7.5 and 15 mm of length were used. The extraction and liquid desorption steps for BAμE were optimized employing multivariate and univariate procedures. The desorption time and solvent used for liquid desorption were optimized by univariate and multivariate studies, respectively. For the extraction step the sample pH was optimized by univariate experiments while the parameters extraction time and ionic strength were evaluated using the Doehlert design. The optimum extraction conditions were sample pH 5.5, NaCl concentration 25% and extraction time 90 min. Liquid desorption was carried out for 30 min with 250 μL (bar length of 15 mm) or 100 μL (bar length of 7.5 mm) of ACN:MeOH (50:50, v/v). The quantification limits varied between 1.6 and 20 μg L(-1) (bar length of 15 mm) and 0.64 and 8 μg L(-1) (bar length of 7.5 mm). The linear correlation coefficients were higher than 0.98 for both bars. The method with 7.5 mm bar length showed recovery values between 65 and 123%. The bar-to-bar reproducibility and the repeatability were lower than 13% (n = 2) and 14% (n = 3), respectively.

The information about adverse effects of emerging contaminants on aquatic protozoa is very scarce. The growth inhibition effect, cell viability, genotoxicity and multixenobiotic resistance (MXR) responses of two commonly used antimicrobial agents, triclosan (TCS) and triclocarban (TCC) to protozoan Tetrahymena thermophila were investigated in this study. The results revealed that TCS and TCC can inhibit the growth of T. thermophila with 24h EC50 values of 1063 and 295μgL(-1), respectively. The impairment of plasma membrane was observed after 2h exposure of TCS or TCC at the level of mg/L. Furthermore, it is noticeable that at environmentally relevant concentration (1.0μgL(-1)), both TCS and TCC can lead to statistically significant DNA damage in T. thermophila, while the inhibition of growth and change of cell viability cannot be observed. Our results firstly provide the evidence for genotoxic effects of TCS and TCC on the freshwater protozoan. Additionally, both TCS and TCC were found to inhibit the efflux transporter activities, with the inhibitory potencies of 39% and 40% (using verapamil as a model inhibitor), respectively. Particularly, TCC could significantly down-regulate the expression of MXR related gene Abcb15, which encodes the membrane efflux protein that acting as P-gp in T. thermophila. The results raise the awareness of potential aquatic ecological and human health risks from the exposure of TCS and TCC, as they might potentiate the toxic effects by chemosensitizing with co-existing toxicants.

In this study, we investigated the possible acute toxic and genotoxic effects of triclosan (TCS) and triclocarban (TCC) on Artemia salina. Genotoxicity was evaluated using single-cell gel electrophoresis and apoptotic frequency assays (Annexin V-FITC/PI assay). Acute toxicity test results showed that TCC (LC50–24 h = 17.8 µg/L) was more toxic than TCS (LC50–24 h = 171.1 µg/L). Significant increases in both genotoxic biomarkers were observed at 24 h after initial exposure, indicating that these two chemicals are potentially dangerous for this aquatic biological model. Although further studies are required, a comparison of data both in vitro and in vivo allowed us to suggest possible mechanisms of action for TCS and TCC in this sentinel organism.

The Na+ ion–assisted recognition of urea derivatives by BPX26C6 has allowed the construction of a redox-controllable [2]rotaxane-type molecular switch based on two originally very weakly interacting host/guest systems. Using NOBF4 to oxidize the triarylamine terminus into a corresponding radical cation attracted the macrocyclic component toward its adjacent carbamate station, subsequent addition of Zn powder moved the macrocyclic component back to its urea station.

Home and personal care products (HPCPs) including biocides, benzotriazoles (BTs) and ultraviolet (UV) filters are widely used in our daily life. After use, they are discharged with domestic wastewater into the receiving environment. This study investigated the occurrence of 29 representative HPCPs, including biocides, BTs and UV filters, in the riverine environment of a rural region of South China where no wastewater treatment plants were present, and assessed their potential ecological risks to aquatic organisms. The results showed the detection of 11 biocides and 4 BTs in surface water, and 9 biocides, 3 BTs and 4 UV filters in sediment. In surface water, methylparaben (MeP), triclocarban (TCC), and triclosan (TCS) were detected at all sites with median concentrations of 9.23 ng/L, 2.64 ng/L and 5.39 ng/L, respectively. However, the highest median concentrations were found for clotrimazole (CLOT), 5-methyl-1H-benzotriazole (MBT) and carbendazim (CARB) at 55.6 ng/L, 33.7 ng/L and 13.8 ng/L, respectively. In sediment, TCC, TCS, and UV-326 were detected with their maximum concentrations up to 353 ng/g, 155 ng/g, and 133 ng/g, respectively. The concentrations for those detected HPCPs in surface water and sediment were generally lower in the upper reach (rural area) of Sha River than in the lower reach of Sha River with close proximity to Dongjiang River (Pt-test

International audience; An analytical method was developed and validated for the target screening of triclosan (TCS), triclocarban (TCC) and its lesser and higher chlorinated congeners namely, 4,4'-dichlorocarbanilide (DCC) 3,3',4,4'-tetrachlorocarbanilide (3-Cl-TCC) and 2,3',4,4'-tetrachlorocarbanilide (2-Cl-TCC) in river sediment. Sediment samples were extracted by pressurized liquid extraction and quantification and identification of target compounds were carried by liquid chromatography high resolution mass spectrometry (LC\textendashHRMS). The overall method recoveries were 89% with relative standard deviations below 6%. Method detection limits ranged from 0.01 to 0.12ng/g. The usefulness of the method was demonstrated on sediment samples collected downstream of three wastewater treatment plants in an attempt to provide with a set of occurrence data of these biocides in France and for a better understanding of their fate in river. Major results are the following: TCC, DCC and 3-Cl-TCC were ubiquitously detected demonstrating that these emerging contaminants have been probably overlooked in France. Reductive dechlorination of TCC into DCC was also ubiquitous but predominated in anoxic sediment. 3-Cl-TCC is probably more persistent than TCC and LC\textendashHRMS enabled the detection and identification of a suite of other chlorinated biocides in river sediment.

The screening of endocrine disrupting chemicals (EDCs) that may alter steroidogenesis represents a highly important field mainly due to the numerous pathologies, such as cancer, diabetes, obesity, osteoporosis, and infertility that have been related to impaired steroid-mediated regulation. The adrenal H295R cell model has been validated to study steroidogenesis by the Organization for Economic Co-operation and Development (OECD) guideline. However, this guideline focuses solely on testosterone and estradiol monitoring, hormones not typically produced by the adrenals, hence limiting possible in-depth mechanistic investigations. The present work proposes an untargeted steroidomic footprinting workflow based on ultra-high pressure liquid chromatography (UHPLC) coupled to high-resolution MS for the screening and mechanistic investigations of EDCs in H295R cell supernatants. A suspected EDC, triclocarban (TCC), used in detergents, cosmetics, and personal care products, was selected to demonstrate the efficiency of the reported methodology, allowing the simultaneous assessment of a steroidomic footprint and quantification of a selected subset of steroids in a single analysis. The effects of exposure to increasing TCC concentrations were assessed, and the selection of features with database matching followed by multivariate analysis has led to the selection of the most salient affected steroids. Using correlation analysis, 11 steroids were associated with a high, 18 with a medium, and 8 with a relatively low sensitivity behavior to TCC. Among the candidates, 13 identified steroids were simultaneously quantified, leading to the evaluation and localization of the disruption of steroidogenesis caused by TCC upstream of the formation of pregnenolone. The remaining candidates could be associated with a specific steroid class (progestogens and corticosteroids, or androgens) and represent a specific footprint of steroidogenesis disruption by TCC. This strategy was devised to be compatible with medium/high-throughput screening and could be useful for the mechanistic elucidation of EDCs.

Aims: To determine minimal inhibitory concentrations (MICs) and the percentage of nonsusceptible bacteria – those still cultivable above a threshold concentration – in human supragingival dental plaque and saliva for antiplaque/antimicrobial agents including triclosan (TCS) and trichlorocarbanilide (TCC), and a new potential antimicrobial, 2-t-butyl-5-(4-t-butylphenyl)-phenol (DTBBP). Methods and Results: Broth and agar dilution-based MIC tests were performed using 28 oral and nonoral bacterial strains representing 17 species. MICs for TCS were lowest and more than 100-fold lower than DTBBP (P

Recent evidence implicates the volume-regulated anion current (VRAC) and other anion currents in control or modulation of cell cycle progression; however, the precise involvement of anion channels in this process is unclear. Here, Cl- currents in Ehrlich Lettre Ascites (ELA) cells were monitored during cell cycle progression, under three conditions: (i) after osmotic swelling (i.e., VRAC), (ii) after an increase in the free intracellular Ca2+ concentration (i.e., the Ca2+-activated Cl- current, CaCC), and (iii) under steady-state isotonic conditions. The maximal swelling-activated VRAC current decreased in G1 and increased in early S phase, compared to that in G0. The isotonic steady-state current, which seems to be predominantly VRAC, also decreased in G1, and increased again in early S phase, to a level similar to that in G0. In contrast, the maximal CaCC current (500 nM free Ca2+ in the pipette), was unaltered from G0 to G1, but decreased in early S phase. A novel high-affinity anion channel inhibitor, the acidic di-aryl-urea NS3728, which inhibited both VRAC and CaCC, attenuated ELA cell growth, suggesting a possible mechanistic link between cell cycle progression and cell cycle-dependent changes in the capacity for conductive Cl- transport. It is suggested that in ELA cells, entrance into the S phase requires an increase in VRAC activity and/or an increased potential for regulatory volume decrease (RVD), and at the same time a decrease in CaCC magnitude.

Nicarbazin (NCZ), a coccidiostat commonly used in the poultry industry, causes reduced hatchability and egg quality in layer hens at a concentration of 125 ppm (8.4 mg/kg) in the feed. Although this effect is undesirable in the poultry industry, NCZ could provide a useful wildlife contraception tool for waterfowl, particularly urban geese. We tested the absorption of NCZ in chickens (Gallus gallus), mallards (Anas platyrhynchos), and Canada geese (Branta canadensis) gavaged with 8.4 mg of NCZ/kg per bird each day for 8 d. Plasma levels of 4,4'-dinitrocarbanilide (DNC) differed significantly among species. Peak plasma DNC levels were 2.87 +/- 0.15 microg/mL, 2.39 +/- 0.15 microg/mL, and 1.53 +/- 0.15 microg/ mL in chickens, mallards, and Canada geese respectively. It took 6 d to obtain peak DNC levels in chickens as opposed to 8 d in mallards and Canada geese. The half life of DNC in plasma was 1.43 d in chickens, 0.72 d in mallards, and 1.26 d in Canada geese. Mallards eliminated 100% of plasma DNC 4 d post-treatment, whereas Canada geese eliminated 100% of plasma DNC 8 d post-treatment. Chickens had only eliminated 99% of plasma DNC 8 d post-treatment. Mallard plasma DNC levels were highly correlated with Canada goose plasma DNC levels. This research showed mallards are an ideal model species for the Canada goose for future reproductive studies on NCZ in a laboratory setting. However, levels higher than 8.4 mg/kg must be fed to waterfowl in order to obtain a plasma level comparable to chickens.

A simple, fast and reliable HPLC-UV method has been developed for the determination of dinitrocarbanilide residues in broiler liver. Liver samples (2 g) were extracted with two portions of acetonitrile (10 and 5 ml), defatted with hexane and evaporated to dryness under nitrogen. Extracts were reconstituted in acetonitrile-water (70/30, v/v, 500 microl), loaded onto C18 solid phase (SPE) cartridges and eluted with acetonitrile-water (70/30, v/v, 2.5 ml) into clean test-tubes. Extracts were evaporated to dryness and reconstituted in acetonitrile-water (80/20, v/v, 500 microl). An aliquot of the extract was assayed by high performance liquid chromatography (HPLC) with UV detection at 350 nm. The method was validated according to EU guidelines using liver tissues fortified at levels of 100, 200 and 300 microg/kg, with dinitrocarbanilide. The decision limit (CC(alpha)) and the detection capability (CC(beta)) were calculated from the within laboratory repeatability data to be 228 and 266 microg/kg, respectively. The mean recovery was typically >70% and the limits of quantitation was 12.5 microg/kg (based on the lowest standard on the calibration curve).

Summary Background More than 3·5 million children aged less than 5 years die from diarrhoea and acute lower respiratory-tract infection every year. We undertook a randomised controlled trial to assess the effect of handwashing promotion with soap on the incidence of acute respiratory infection, impetigo, and diarrhoea. Methods In adjoining squatter settlements in Karachi, Pakistan, we randomly assigned 25 neighbourhoods to handwashing promotion; 11 neighbourhoods (306 households) were randomised as controls. In neighbourhoods with handwashing promotion, 300 households each were assigned to antibacterial soap containing 1·2% triclocarban and to plain soap. Fieldworkers visited households weekly for 1 year to encourage handwashing by residents in soap households and to record symptoms in all households. Primary study outcomes were diarrhoea, impetigo, and acute respiratory-tract infections (ie, the number of new episodes of illness per person-weeks at risk). Pneumonia was defined according to the WHO clinical case definition. Analysis was by intention to treat. Findings Children younger than 5 years in households that received plain soap and handwashing promotion had a 50% lower incidence of pneumonia than controls (95% CI (−65% to −34%). Also compared with controls, children younger than 15 years in households with plain soap had a 53% lower incidence of diarrhoea (−65% to −41%) and a 34% lower incidence of impetigo (−52% to −16%). Incidence of disease did not differ significantly between households given plain soap compared with those given antibacterial soap. Interpretation Handwashing with soap prevents the two clinical syndromes that cause the largest number of childhood deaths globally—namely, diarrhoea and acute lower respiratory infections. Handwashing with daily bathing also prevents impetigo.

It is well known that water-soluble cyclodextrins form inclusion complexes with many lipophilic water-insoluble drugs and that such complexation frequently enhances the aqueous solubility of drugs. It is also well known that various excipients, such as water-soluble polymers, organic acids and bases and metal ions can enhance the solubilizing effects of cyclodextrins. However, it is not clear how these excipients enhance the effects. The effects of cyclodextrins, 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) and randomly methylated beta-cyclodextrin (RMbetaCD) on the aqueous solubility of triclosan and triclocarban were investigated. The phase-solubility profiles were all of type A(P) indicating formation of higher-order complexes or complex aggregates. Addition of lysine and other excipients enhanced the RMbetaCD solubilization of triclocarban. NMR spectroscopic studies, including 2D ROESY and 1D gROESY techniques, indicated that HPbetaCD and RMbetaCD, as well as their complexes, form aggregates of two to three cyclodextrin molecules. The critical concentration for the aggregate formation was determined to be 5.4% (w/v). Lysine, polyvinylpyrrolidone and magnesium ions formed non-inclusion complexes resulting in formation of multiple-component cyclodextrin complexes in aqueous solutions with triclocarban.

Triclocarban, N-(4-chlorophenyl)-N'-(3,4-dichlorophenyl)urea, is a polychlorinated phenyl urea pesticide, marketed under the trademark TCC and used primarily as an antibacterial additive in personal care products. Despite its extensive use over several decades, environmental occurrence data on TCC are scarce. This is due in part to a lack of analytical techniques offering the desired sensitivity, selectivity, affordability, and ease of use. This need is addressed here by introducing a liquid chromatography electrospray ionization mass spectrometry (LC/ESI/MS) method allowing for the determination of TCC concentrations in aquatic environments at the ng/L level. TCC was concentrated from aqueous samples by solid-phase extraction, separated from interferences on a C18 column by either isocratic or gradient elution, and detected and identified in negative ESI mode by selectively monitoring the (M - H)- base peak (m/z 313) and its 37Cl-containing isotopes (m/z 315, 317) that served as reference ions. Particulates contained in aquatic samples were extracted and analyzed separately. Accurate quantification was achieved using stable isotopes of TCC and triclosan as internal standards. Addition of 10 mM acetic acid to the mobile phase yielded acetic acid adducts ([M - H + 60]-) that were successfully exploited to boost method sensitivity and selectivity, especially when analyzing challenging environmental matrixes. Method detection limits were matrix dependent, ranging from 3 to 50 ng/L. In 36 grab samples obtained from the Greater Baltimore area, TCC was detected in river water and wastewater at concentrations of up to 5600 and 6750 ng/L, respectively. Raw and finished drinking water did not contain detectable quantities of the pesticide (

We have previously reported the novel lead compound 1a as a CCR5 antagonist for treatment of HIV-1 infection. SAR studies on incorporating various acyl groups as a replacement for the 5-oxopyrrolidine-3-carbonyl group of the lead structure resulted in the discovery of N -[3-(4-benzylpiperidin-1-yl)propyl]- N , N ′ -diphenylurea ( 4a ) with significantly improved CCR5 binding affinity. Substitutions (4-Cl, 4e , f ; 4-Me, 4i ) on the N ′ -phenyl ring further increased the binding affinity. Introduction of polar substituents on the phenyl ring of the 4-benzylpiperidine moiety enhanced the inhibitory activity of the HIV-1 envelope-mediated membrane fusion ( 4v , w ), suggesting that polar substituents at this position can interfere effectively with HIV-1 cell entry.

Yersinia enterocolitica is an important foodborne pathogen, but isolation of virulent Yersinia from food sources is still time consuming and requires skills. In this article, we describe a rapid urease screening on cefsulodin–irgasan–novobiocin (CIN) agar plates with an agar overlay assay. This test is simple to perform, all colonies on a plate can be checked simultaneously, it only takes minutes for detection of urease-positive colonies and the colonies survive for transfer, further characterisation, and storage. Additionally, this method is useful to isolate virulent (urease-positive and pYV harbouring) Y. enterocolitica from foodstuffs.

S.E. W ALSH, J .-Y. M AILLARD, A .D. R USSELL, C .E. C ATRENICH, D .L. C HARBONNEAU A ND R . G . B A R T O L O . 2003. Aims: This study investigates the antimicrobial activity and mode of action of two natural products, eugenol and thymol, a commonly utilized biostatic agent, triclocarban (TCC), and two surfactants, didecyldimethylammonium chloride (DDDMAC) and C10–C16 alkyldimethyl amine N-oxides (ADMAO). Methods and Results: Methods used included: determination of minimum inhibitory concentrations (MICs), lethal effect studies with suspension tests and the investigation of sub-MIC concentrations on growth of E. coli, Staph. aureus and Ps. aeruginosa using a Bioscreen microbiological analyser. Leakage of intracellular constituents and the effects of potentiating agents were also investigated. Only DDDMAC was bactericidal against all of the organisms tested. Eugenol, thymol and ADMAO showed bacteriostatic and bactericidal activity, but not against Ps. aeruginosa. TCC was only bacteristatic against Staph. aureus, but like the other agents, it did affect the growth of the other organisms in the Bioscreen experiments. All of the antimicrobial agents tested were potentiated by the permeabilizers to some extent and leakage of potassium was seen with all of the agents except TCC. Conclusions: DDDMAC was bactericidal against all organisms tested and all compounds had some bacteriostatic action. Low level static effects on bacterial growth were seen with sub-MIC concentrations. Membrane damage may account for at least part of the mode of action of thymol, eugenol, DDDMAC and ADMAO. Significance and Impact of the Study: The ingredients evaluated demonstrated a range of bactericidal and bacteriostatic properties against the Gram-negative and -positive organisms evaluated and the membrane (leakage of intracellular components) was implicated in the mode of action for most (except TCC). Sub-MIC levels of all ingredients did induce subtle effects on the organisms which impacted bacterial growth, even for those which had no true inhibitory effects.

A method was developed using high-performance liquid chromatography to assay 4,4'-dinitrocarbanilide (DNC), the active ingredient in Nicarbazin, in eggshells collected from Canada geese fed a formulated feed fortified with Nicarbazin at doses of 0, 125, 250, and 500 microg/g. The method was developed using chicken eggshells fortified with DNC. The method was used to quantify DNC in both the shell-associated membranes and the calcified shell extracellular matrix. These values were compared to those obtained for a composite sample consisting of both the membranes and the calcified shell extracellular matrix. The validated method was used to quantify DNC in eggshells from geese fed fortified feed to ascertain the effect of Nicarbazin feed concentration on shell DNC concentration. DNC levels in the eggshells were highly correlated with feed dose.

The antibacterial triclocarban (TCC) concentrates in the cellular fraction of blood. Consequently, plasma levels are at least two-fold lower than the TCC amount present in blood. Utilizing whole blood sampling, a low but significant absorption of TCC from soap during showering is demonstrated for a small group of human subjects.

Polyclonal antibodies were produced to detect the coccidiostat nicarbazin. Due to structural constraints of the active component of nicarbazin, dinitrocarbanilide (DNC), three different compounds that shared a common substructure with DNC were used as antigen mimics. The compounds (N-suceinyl-L-alanyl-L-alanyl-L-alanine 4-nitroanilide (SAN), L-glutamic acid gamma-(p-nitroanilide) (GAN) and p-nitrosuccinanilic acid (NSA)) were conjugated to a carrier protein and used in the immunisation of rabbits. Five different polyclonal sera were produced and consequently characterised. The antibodies exhibited an IC50 range of 2.3-7.6 ng/ml using a competitive ELISA procedure, Serum from one rabbit, R555, exhibited an IC50 of 2.9 ng/ml for DNC and cross-reactivity studies showed that this serum was specific for DNC and did not cross-react with other coccidiostats such as halofuginone, toltrazuril or ronidazole. (C) 2002 Elsevier Science B.V. All rights reserved.

Urbanization and associated landscaping has increased the abundance of year-round habitat for waterfowl, resulting in vegetation damage, loss of recreational activities, air transportation mishaps and health hazards. As part of a research program to develop socially acceptable techniques for management of pest bird populations, we are evaluating nicarbazin as a contraceptive in pest and surrogate avian species. As reproductive studies with Canada Geese (Branta canadensis) are tedious due to the difficulty of conducting controlled field studies and/or breeding geese in captivity, we evaluated the effects of oral nicarbazin administration on the production and hatchability of chicken eggs. Blood plasma and egg DNC concentrations were correlated to contraceptive efficacy. Subsequent studies are being conducted with geese to determine the diet nicarbazin concentration required to produce the desired blood and plasma DNC concentrations. This approach permits the expeditious evaluation of formulations and dosing regimes by simply monitoring blood DNC concentrations in target species.

Doxorubicin is a highly effective anti-cancer chemotherapy agent, but its usage is limited by its cardiotoxicity. To develop a drug that prevents the cardiac toxicity of doxorubicin while preserving its anti-tumor potency, we established a doxorubicin-induced cardiomyopathy model in zebrafish that recapitulated the cardiomyocyte apoptosis and contractility decline observed in patients. Using this model, we screened 3000 compounds and discovered that visnagin (VIS) and diphenylurea (DPU) rescue cardiac performance and circulatory defects caused by doxorubicin treatment in zebrafish. VIS and DPU reduced doxorubicin-induced apoptosis in cultured cardiomyocytes and in vivo in zebrafish and mouse hearts. Furthermore, VIS treatment improved cardiac contractility in doxorubicin-treated mice. Importantly, VIS and DPU caused no reduction in the chemotherapeutic efficacy of doxorubicin in several cultured tumor lines or in zebrafish and mouse xenograft models. Using affinity chromatography, we discovered that VIS binds to mitochondrial malate dehydrogenase (MDH2), one of the key enzymes in the tricarboxylic acid cycle. As with VIS, treatment with the MDH2 inhibitors mebendazole, thyroxine, and iodine prevented doxorubicin cardiotoxicity, as did treatment with malate itself, suggesting that modulation of MDH2 activity is responsible for VIS’s cardioprotective effects. Taken together, this study identified VIS and DPU as potent cardioprotective compounds and implicates MDH2 as a previously undescribed, druggable target for doxorubicin-induced cardiomyopathy.

Nineteen biocides were investigated in the Yangtze River to understand their spatiotemporal distribution, mass loads and ecological risks. Fourteen biocides were detected, with the highest concentrations up to 166 ng/L for DEET in surface water, and 54.3 ng/g dry weight (dw) for triclocarban in sediment. The dominant biocides were DEET and methylparaben, with their detection frequencies of 100% in both phases. An estimate of 152 t/y of 14 biocides was carried by the Yangtze River to the East China Sea. The distribution of biocides in the aquatic environments was significantly correlated to Gross Domestic Product (GDP), total phosphorus (TP) and total nitrogen (TN), suggesting dominant input sources from domestic wastewater of the cities along the river. Risk assessment showed high ecological risks posed by carbendazim in both phases and by triclosan in sediment. Therefore, proper measures should be taken to reduce the input of biocides into the river systems.

Triclocarban (3,4,4'-trichlorocarbanilide; TCC) is an antibacterial agent used in personal care products such as bar soaps. Small amounts of chemical are absorbed through the epidermis. Recent studies show that residues of reactive TCC metabolites are bound covalently to proteins in incubations with keratinocytes, raising concerns about the potential toxicity of this antimicrobial agent. To obtain additional information on metabolic activation of TCC, this study characterized the reactive metabolites trapped as glutathione conjugates. Incubations were carried out with (14)C-labeled TCC, recombinant CYP1A1 or CYP1B1, coexpressed with cytochrome P450 reductase, glutathione-S-transferases (GSH), and an NADPH-generating system. Incubations containing CYP1A1, but not 1B1, led to formation of a single TCC-GSH adduct with a conversion rate of 1% of parent compound in 2 hours. Using high-resolution mass spectrometry and diagnostic fragmentation, the adduct was tentatively identified as 3,4-dichloro-3'-glutathionyl-4'-hydroxycarbanilide. These findings support the hypothesis that TCC is activated by oxidative dehalogenation and oxidation to a quinone imine. Incubations of TCDD-induced keratinocytes with (14)C-TCC yielded a minor radioactive peak coeluting with TCC-GSH. Thus, we conclude that covalent protein modification by TCC in TCDD-induced human keratinocyte incubations is mainly caused by activation of TCC by CYP1A1 via a dehalogenated TCC derivative as reactive species.

Structural organization of macromolecules is highly dependent on the conformational propensity of the monomer units. Our goal is to systematically quantify differences in the conformational propensities of aromatic oligourea foldamer units. Specifically, we investigate the conformational propensities of N,N'-diphenylurea and N,N'-dimethyl-N,N'-diphenylurea in different media using a combination of theoretical methods, and infrared and nuclear magnetic resonance spectroscopies. Our results show variation in the conformational behavior upon adding methyl substituents on N,N'-diphenylurea, and varying the environments surrounding the compounds. Our energetic analyses and conformational distributions in the gas phase show predominance of the cis-trans and trans-trans conformations for N,N'-diphenylurea, while cis-cis conformation is favored for N,N'-dimethyl-N,N'-diphenylurea. In solution, our results support the trans-trans conformer as the predominant conformer for N,N'-diphenylurea, whereas the cis-cis and cis-trans forms are favored in N,N'-dimethyl-N,N'-diphenylurea. N,N'-Dimethyl-N,N'-diphenylurea also exhibits a more dynamic conformational behavior in solution, with constant fluctuations between cis-cis and cis-trans conformations. Our detailed quantitative analyses are an important aspect in fine-tuning desired conformations and dynamic properties of this class of oligomers by providing a molecular basis for the behavior at the monomeric level.

The occurrence of triclosan (TCS) and triclocarban (TCC) in a subtropical river (Jiulong River) and its estuary was investigated for two years. TCS and TCC were ubiquitously detected in the Jiulong River and its estuary. The levels of TCS and TCC ranged from less than the method detection limit to 64 ng/L and from 0.05 to 14.1 ng/L in the river, respectively. The levels of TCS and TCC in the estuary ranged from 2.56 to 27.25 ng/L and 0.38 to 5.76 ng/L, respectively. Temporal and spatial variations of TCS and TCC in the Jiulong River and its estuary were observed during the investigation. The weather conditions did not show significant correlations with TCS and TCC, whereas several water quality parameters showed high correlations with TCS and TCC. The microcosm studies showed that both direct photolysis and biodegradation contributed to TCS removal, whereas indirect photolysis was important for TCC removal in the surface water.

A single-laboratory validation (SLV) study was conducted on an LC/MS/MS method for the determination and confirmation of nicarbazin, expressed as 4,4-dinitrocarbanilide (DNC), in chicken tissues, including liver, kidney, muscle, skin with adhering fat, and eggs. Linearity was demonstrated with DNC standard curve solutions using a weighted (1/x) regression and confirmed with matrix-matched standards. Intertrial repeatability precision (relative standard deviation of repeatability; RSDr) was from 2.5 to 11.3%, as determined in fortified tissues. The precision was verified with incurred tissue, and varied from 0.53 to 2.5%. Average recoveries ranged from 82% in egg to 98% in kidney. Although the average recoveries across all concentrations were within the acceptable range, the method was improved with the inclusion of an internal standard and the use of matrix-matched standards. Accuracy for the improved method in chicken liver varied from 93 to 99% across all concentrations (100–8000 ng/g) compared to recoveries below 80% at concentrations between 100–400 ng/g in chicken liver for the original method. The limit of detection was estimated to be less than 3.0 ng/g in all tissue types, and the limit of quantitation was validated at 20 ng/g. Based on confirmatory ion ratios and peak retention times, the false-negative rate was estimated as 0.00% (95% confidence limits 0.00, 0.74%) from 484 fortified samples and 12 incurred residue samples analyzed using the U.S. and EU confirmation criteria. Small variations to the method parameters, with the exception of injection volume, did not have a significant effect on recoveries. Stability was determined for fortified tissues, extracts, and standard curve solutions. The data collected in this study satisfy the requirements of SLV studies established by the AOAC Stakeholder Panel for Veterinary Drug Residue and the method was awarded First Action Official MethodSM status by the Expert Review Panel for Veterinary Drug Residues on May 7, 2013.

The photolysis of the antimicrobial triclocarban (TCC) in aqueous systems under simulated sunlight irradiation was studied. The effects of several abiotic parameters, including solution pH, initial TCC concentration, presence of natural organic matter, and most common inorganic anions in surface waters, were investigated. The results show that the photolysis of TCC followed pseudo-first-order kinetics. The TCC photolysis rate constant increased with increasing solution pH and decreasing the initial TCC concentration. Compared with the TCC photolysis in pure water, the presence of aqueous bicarbonate, nitrate, humic acids, and its sodium salt decreased the TCC photolysis rate, but fulvic acid increased the TCC photolysis rate. The electron spin resonance and reactive oxygen species scavenging experiments indicated that TCC may undergo two different types of phototransformation reactions: direct photolysis and energy transfer to generate (1)O2. The main degradation products were tentatively identified by gas chromatography interfaced with mass spectrometry (GC-MS), and a possible degradation pathway was also proposed.

International audience; The objective of this study was to examine the occurrence of parabens (5 congeners), triclosan (TCS) and triclocarban (TCC) at the scale of the Parisian sewer network and to provide representative knowledge on these compounds in France for a large area. For this purpose and in collaboration with the Parisian public sanitation service (SIAAP) in charge of the collect and treatment of the Parisian wastewater, this study focused on seven main sewer trunks of the Paris conurbation, accounting for 1900,000 m(3) d(-1), i.e., about 8 million inhabitants. Concentrations lying in the 2000-20000 ng l(-1) ranges were found in wastewater, confirming the ubiquity of parabens, TCS and TCC in our environment and household products. Parabens (>97%) and to a lesser extent TCS (68% in median) were mainly associated to the dissolved fraction, as demonstrated by low KD and KOC values. For the first time, this study also evaluated the pollutant mass loads per population equivalent (PE) of parabens, TCS and TCC at the large and representative scale of the Parisian conurbation. Hence, the median mass loads varied from 176 to 3040 μg PE(-1) d(-1) for parabens and from 26 to 762 μg PE(-1) d(-1) for TCS and TCC. Based on these results and according to the assumptions done, the extrapolation of the mass loads at the national scale pointed out an annual mass loads between 51.8 and 100.7 ty(-1) for methyl paraben (MeP) and between 11.2 and 23.5 ty(-1) for TCS. Mass loads per equivalent habitant and national mass loads are both extremely relevant and innovative data. Contrary to other countries, such data are nowadays rather difficult to gain in France and neither enquiry nor database provides access to information on the use and production of these chemicals. Since cosmetic industries are voluntarily and fully engaged in the substitution of parabens, triclosan and triclocarban in personal care product, this study could constitute a "time reference status" which could be used as a basis for future monitoring.

In the US, land application of biosolids has been utilized in government-regulated programs to recycle valuable nutrients and organic carbon that would otherwise be incinerated or buried in landfills. While many benefits have been reported, there are concerns that these practices represent a source of organic micropollutants to the environment. In this study, biosolids samples from a wastewater treatment plant in the Mid-Atlantic region of the US were collected approximately every 2 months over a 7-year period and analyzed for brominated diphenyl ethers (BDE-47, BDE-99, and BDE-209), triclosan, and triclocarban. During the collection period of 2005–2011, concentrations of the brominated diphenyl ethers BDE-47 + BDE-99 decreased by 42%, triclocarban decreased by 47%, but BDE-209 and triclosan remained fairly constant. Observed reductions in contaminant concentrations could not be explained by different seasons or by volumetric changes of wastewaters arriving at the treatment plant and instead may be the result of the recent phaseout of BDE-47 and BDE-99 as well as potential reductions in the use of triclocarban.

The polychlorinated aromatic antimicrobials triclosan and triclocarban are in widespread use for killing microorganisms indiscriminately, rapidly, and by nonspecific action. While their utility in healthcare settings is undisputed, benefits to users of antimicrobial personal care products are few to none. Yet, these latter, high-volume uses have caused widespread contamination of the environment, wildlife, and human populations. This feature article presents a timeline of scientific evidence and regulatory actions in the U.S. concerning persistent polychlorinated biocides, showing a potential path forward to judicious and sustainable uses of synthetic antimicrobials, including the design of greener and safer next-generation alternatives.

The antimicrobial compounds triclosan (TCS) and triclocarban (TCC) accumulate in sludges produced during municipal wastewater treatment and persist through sludge treatment processes into finished biosolids. The objective of this research was to determine the extent to which conventional sludge processing systems such as aerobic digestion, anaerobic digestion, and lime stabilization were able to remove TCC and TCS. Sludge and biosolid samples were collected from 10 municipal wastewater treatment plants in the United States. The concentrations of TCC and TCS in sludge and biosolid samples were determined via heated solvent extraction and analysis with liquid chromatography electrospray ionization mass spectrometry. Dry weight concentrations of TCC and TCS frequently were higher in finished biosolids than in the source sludges because of sludge mass reduction during digestion. The removal of TCC and TCS in municipal biosolid processing systems was determined from the measured concentration change after correcting for reductions in solid mass during sludge treatment. Removal in the digester systems ranged from 15 – 68 % for TCC and 20 – 75 % for TCS. Increased solid retention times during sludge treatment operations were correlated with higher removals of TCC and TCS. Apparent first order degradation rates for TCC ranged from 0.015–0.08 1/d and for TCS were between 0.003–0.15 1/d.

The present study investigated the dissipation behaviors of 4 typical personal care products (PCPs)-triclocarban (TCC), triclosan (TCS), tonalide (AHTN), and galaxolide (HHCB)- in soils amended with biosolids under field conditions in North China. The results showed that the 4 target compounds were detected in all biosolids-amended soils at levels of a few nanograms per gram to thousands of nanograms per gram (dry wt). The residual concentrations of the 4 PCPs were found in the following order: TCC TCS AHTN HHCB. Significant dissipation of the 4 PCPs was observed in the biosolids-amended soils, with half-lives ranging from 26 d to 133 d. Furthermore, repeated biosolids applications and a higher biosolids application rate could lead to higher accumulation of the 4 PCPs in the agricultural soils. Based on the detected concentrations in the field trial and limited ecotoxicity data, high risks to soil organisms are expected for TCC, whereas low to medium risks are expected in most cases for AHTN, HHCB, and TCS.

An analytical method was developed to simultaneously detect triclosan (TCS) and triclocarban (TCC) in human nails using solid phase extraction (SPE) with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Nail clippings were digested by sodium hydroxide, and then concentrated and purified with C18 cartridges. Chromatographic separation was performed on a Waters ACQUITY UPLC HSS T3 column (100 mm x 2.1 mm, 1.8 microm) with gradient elution using methanol and water at a flow rate of 0.3 mL/min. The target compounds were determined by triple quadrupole mass spectrometer operated in the negative ion mode and quantified by isotopic-dilution technique. The satisfactory linearities (r2 = 0.999) was obtained over the ranges of 0.5-500.0 microg/kg for TCS and 0.1-100.0 microg/kg for TCC, with the limits of quantification (LOQs) of 2.0 microg/kg for TCS and 0. 2 microg/kg for TCC. The average recoveries of the two target compounds (spiked at three concentration levels) ranged from 95.9% to 110.2%, with the relative standard deviations (RSDs) between 0.6% and 9.7% (n = 6). This method can be applied in rapid detection of target contaminants in nails due to its high sensitivity, high recovery and good reproducibility. Sixty collected human nail samples were analyzed by means of the developed method. TCS and TCC were detected in all samples with content ranges ofLOQ-760.7 microg/kg and 4.1-1926.5 microg/kg, respectively.

Biosolids are an important source of nutrients and organic matter, which are necessary for the productive cultivation of crop plants. Biosolids have been found to contain the personal care products triclosan and triclocarban at high concentrations relative to other pharmaceuticals and personal care products. The present study investigates whether exposure of 6 plant species (radish, carrot, soybean, lettuce, spring wheat, and corn) to triclosan or triclocarban derived from biosolids has an adverse effect on seed emergence and/or plant growth parameters. Plants were grown in soil amended with biosolids at a realistic agronomic rate. Biosolids were spiked with triclosan or triclocarban to produce increasing environmentally relevant exposures. The concentration of triclosan and triclocarban in biosolids-amended soil declined by up to 97% and 57%, respectively, over the course of the experiments. Amendment with biosolids had a positive effect on the majority of growth parameters in radish, carrot, soybean, lettuce, and wheat plants. No consistent triclosan- or triclocarban-dependent trends in seed emergence and plant growth parameters were observed in 5 of 6 plant species. A significant negative trend in shoot mass was observed for lettuce plants exposed to increasing concentrations of triclocarban (p0.001). If best management practices are followed for biosolids amendment, triclosan and triclocarban pose a negligible risk to seed emergence and growth of crop plants.

This article investigates the bioluminescence inhibition effects of the antimicrobials triclocarban, triclosan and its metabolite methyl triclosan, using the marine bacterium Vibrio fischeri as the test organism (Microtox©). The concentration response analysis was performed for the three individual substances and for a mixture in which the three compounds were mixed in a ratio of the IC50 of the individual components (equitoxic ratio). Toxicity values (the median inhibitory concentration value, in mg L−1) in the decreasing order of sensitivity were triclosan (0.73) > triclocarban (0.91) > methyl-triclosan (1.76). The comparison of the experimental data with those obtained by using Quantitative Structure–Activity Relationship (QSAR) equations indicated that triclosan and triclocarban act as polar narcotic compounds towards V. fischeri, whereas methyl-triclosan acts as a narcotic (baseline toxicity). The toxicity of the mixture was measured experimentally and predicted by two models (CA: concentration addition; IA: independent action). The results showed that the observed mixture toxicity (IC50 = 0.23 mg L−1) had no significant differences from those predicted by both CA and IA models.

Y. enterocolitica and Y. pseudotuberculosis are important food borne pathogens. However, the presence of competitive microbiota makes the isolation of Y. enterocolitica and Y. pseudotuberculosis from naturally contaminated foods difficult. We attempted to evaluate the performance of a modified Cefsulodin-Irgasan-Novobiocin (CIN) agar in the differentiation of Y. enterocolitica from non-Yersinia species, particularly the natural intestinal microbiota. The modified CIN enabled the growth of Y. enterocolitica colonies with the same efficiency as CIN and Luria-Bertani agar. The detection limits of the modified CIN for Y. enterocolitica in culture medium (10 cfu/ml) and in artificially contaminated pork (10(4) cfu/ml) were also comparable to those of CIN. However, the modified CIN provided a better discrimination of Yersinia colonies from other bacteria exhibiting Yersinia-like colonies on CIN (H2S-producing Citrobacter freundii, C. braakii, Enterobacter cloacae, Aeromonas hydrophila, Providencia rettgeri, and Morganella morganii). The modified CIN exhibited a higher recovery rate of Y. enterocolitica from artificially prepared bacterial cultures and naturally contaminated samples compared with CIN. Our results thus demonstrated that the use of modified CIN may be a valuable means to increase the recovery rate of food borne Yersinia from natural samples, which are usually contaminated by multiple types of bacteria.

Malarial parasites rely on aspartic proteases called plasmepsins to digest hemoglobin during the intraerythrocytic stage. Plasmepsins from Plasmodium falciparum and Plasmodium vivax have been cloned and expressed for a variety of structural and enzymatic studies. Recombinant plasmepsins possess kinetic similarity to the native enzymes, indicating their suitability for target-based antimalarial drug development. We developed an automated assay of P. falciparum plasmepsin II and P. vivax plasmepsin to quickly screen compounds in the Walter Reed chemical database. A low-molecular-mass (346 Da) diphenylurea derivative (WR268961) was found to inhibit plasmepsins with a K i of 1 to 6 μM. This compound appears to be selective for plasmepsin, since it is a poor inhibitor of the human aspartic protease cathepsin D ( K i greater than 280 μM). WR268961 inhibited the growth of P. falciparum strains W2 and D6, with 50% inhibitory concentrations ranging from 0.03 to 0.16 μg/ml, but was much less toxic to mammalian cells. The Walter Reed chemical database contains over 1,500 compounds with a diphenylurea core structure, 9 of which inhibit the plasmepsins, with K i values ranging from 0.05 to 0.68 μM. These nine compounds show specificity for the plasmepsins over human cathepsin D, but they are poor inhibitors of P. falciparum growth in vitro. Computational docking experiments indicate how diphenylurea compounds bind to the plasmepsin active site and inhibit the enzyme.

A cELISA was developed for the coccidiostat nicarbazin. On the basis of previous computer-assisted molecular modeling studies, p-nitrosuccinanilic acid (PNA-S) was selected as a hapten to produce antibodies to 4,4'-dinitrocarbanilide (DNC), the active component of the coccidiostat nicarbazin. Synthesis is described for the hapten [p-nitro-cis-1,2-cyclohexanedicarboxanilic acid (PNA-C)] used in a BSA conjugate as a plate coating antigen. Monoclonal antibodies (Mabs) were isolated that compete with nicarbazin, having IgM(kappa) isotype. Because of the lack of water solubility of nicarbazin, N,N-dimethylformamide (DMF) (3%, v/v) and acetonitrile (ACN) (10%, v/v) were added to the assay buffer to achieve solubility of nicarbazin and related compounds. The Nic 6 Mabs had an IC(35) value for nicarbazin of 0.92 nmol/mL, with a limit of detection of 0.33 nmol/mL. Nic 6 exhibited high cross-reactivity for PNA-S and PNA-C, and 3-nitrophenol, 4-nitrophenol, and 1-(4-chlorophenyl)-3-(4-nitrophenyl) urea. However, Nic 6 had little or no cross-reactivity with 15 other related compounds.

An ion-interaction high-performance liquid chromatography (HPLC)-diode-array detection method is developed and optimized for the separation of typical antimicrobial agents used in cosmetics and hygiene products. The most used preservatives contain different molecular structures, different functionalities, and are characterized by different chemical properties. Organic acids, alkyl esters of benzoic acids, alkyl p-hydroxy benzoic acids (parabens), phenol derivatives, and carbanilides represent the most used preservatives, and are often present in multicomponent mixtures. In order to develop a multicomponent method to be used in quality control analysis, the ion-interaction reagent reversed-phase HPLC technique seems to be particularly suitable, because it allows for the simultaneous separation of acidic, basic, and neutral species. The experimental conditions of the method are developed by OVAT (one variable at a time) treatment and further optimized by a multivariate approach based on a Simplex algorithm that works on a desirability function targeted to maximize the resolution in a multicomponent mixture. The new method proposed that is able to simultaneously separate fourteen preservatives is applied in the analysis of commercial products.

The affect of the anti-microbial agent triclosan (alternative names Microban® and Irgasan DP300) on the light emission by the bioluminescent bacterium Vibrio fischeri was determined. Triclosan at concentrations greater than 0.2% (w/v) caused cell lysis and immediate (

A quick, simple and reliable analysis method has been developed in order to determine berenil, phenamidine, diampron and dibromopropamidine by capillary zone electrophoresis in samples of serum and urine. In order to define the operation parameters in CZE, we have carried out a study on how the apparent electrophoretic mobility (mu(app)) varies when pH, buffer concentration, voltage and temperature are modified. Ohm's law plot has been studied, too. With the data obtained from this study we have determined the optimum work conditions, which are: citrate buffer 25 mM, pH=3.70, 14 kV, 30 degrees C, wavelength of the UV detector: 200 nm, capillary tube: 570 mm x 75 microm. Under these conditions, all the products appear in times between: 7.6 min phenamidine and 8.8 min dibromopropamidine, limits of detection being: berenil: 0.50, phenamidine: 0.25, diampron: 0.40 and dibromopropamidine: 0.80 microg ml(-1). We have carried out a recovery study with three kinds of extraction cartridges: Sep-pak C-18 plus, Sep-pak C-8 plus and Oasis HBL for each one of the products in blood and urine.

Triclosan (TCS) and triclocarban (TCC), as broad spectrum antibacterial agents, are distributed widely in the environment and humans. Most studies have focused on their distribution and biodegradation, but the endocrine-disrupting effects of these chemicals, especially their estrogenic effects, are still unclear. In the present study, we investigated the estrogenic effects of TCS and TCC using a series of in vitro assays, including the ER reporter gene assay in the CV-1 cells, E-screen assay and evaluation of estrogen-responsive genes in the MCF-7 cells. The tested concentrations of TCS and TCC were both from 1 × 10(-9) to 1 × 10(-6) M. Results showed that TCS and TCC exerted estrogenic activities by inducing luciferase activities in an ER reporter gene assay, promoting the proliferation of the MCF-7 cells, up-regulating the expression of pS2 and down-regulating ERα expression at both the mRNA and protein levels in the MCF-7 cells. We further found that TCS and TCC could alter the expression of multiple microRNAs (mir-22, mir-206 and mir-193b) in the MCF-7 cells, which would help understand the mechanisms of their estrogenic effects on regulating the expression of ERα. In brief, our results demonstrated the potential estrogenic effects and profiled in vitro data for further risk assessment of TCS and TCC.

Biosolids generally contain the microbiocidal agents triclosan (TCS) and triclocarban (TCC) that are persistent during wastewater treatment and sorp to organic material. The present study investigated the concentration of TCS in tissues of radish, carrot, and soybean grown in potted soil amended with biosolids. Highest mean concentrations of TCS in radish, carrot, and soybean root tissue midway through the life cycle were 24.8 ng/g, 49.8 ng/g, and 48.1 ng/g dry weight, respectively; by the conclusion of the test, however, concentrations had declined to 2.1 ng/g, 5.5 ng/g, and 8.4 ng/g dry weight, respectively. Highest mean concentrations of TCS in radish and carrot shoot tissue were 33.7 and 18.3 ng/g dry weight at days 19 and 45, respectively, but had declined to 13.7 ng/g and 5.5 ng/g dry weight at days 34 and 69, respectively. Concentration of TCS in all samples of soybean seeds was below method detection limit (i.e., 2.8 ng/g dry wt). The present study also examined the concentration of TCS and TCC in edible portions of green pepper, carrot, cucumber, tomato, radish, and lettuce plants grown in a field amended with biosolids. Triclosan was detected only in cucumber and radish up to 5.2 ng/g dry weight. Triclocarban was detected in carrot, green pepper, tomato, and cucumber up to 5.7 ng/g dry weight. On the basis of the present study and other studies, we estimate that vegetable consumption represents less than 0.5% of the acceptable daily intake of TCS and TCC. These results demonstrate that, if best management practices for land application of biosolids in Ontario are followed, the concentration of TCS and TCC in edible portions of plants represents a negligible exposure pathway to humans.