Sunlight enhanced the formation of tribromomethane from benzotriazole degradation during the sunlight/free chlorine treatment in the presence of bromide.

The coexistence of free chlorine and bromide under sunlight irradiation (sunlight/FC with Br-) is unavoidable in outdoor seawater swimming pools, and the formation of brominated disinfection byproducts could act more harmful than chlorinated disinfection byproducts. In this study, benzotriazole was selected as a model compound to investigate the degradation rate and the subsequent formation of disinfection byproducts via sunlight/FC with Br- process. The rate constants for the degradation of benzotriazole under pseudo first order conditions in sunlight/FC with Br- and sunlight/FC are 2.3 ± 0.07 × 10-1 min-1 and 6.0 ± 0.7 × 10-2 min-1, respectively. The enhanced degradation of benzotriazole can be ascribed to the generation of HO•, bromine species, and reactive halogen species (RHS) during sunlight/FC with Br-. Despite the fact that sunlight/FC with Br- process enhanced benzotriazole degradation, the reaction results in increasing tribromomethane (TBM) formation. A high concentration (37.8 µg/L) of TBM was detected in the sunlight/FC with Br-, which was due to the reaction of RHS. The degradation of benzotriazole was notably influenced by the pH value (pH 4 - 11), the concentration of bromide (0 - 2 mM), and free chlorine (1 - 6 mg/L). Furthermore, the concentration of TBM increased when the free chlorine concentrations increased, implying the formation potential of harmful TBM in chlorinated seawater swimming pools.

Pharmacokinetics of bromoform in dairy heifers.

AIMS: To determine the pharmacokinetics in dairy heifers after oral and IV administration of bromoform, a potential antimethanogenic agent found in red seaweed, Asparagopsis spp. METHODS: Twenty-four dairy heifers with a mean weight of 319 (SD 36.9) kg were used. The study was conducted in two phases, and each cohort of 12 heifers received an escalating dose of bromoform. In the first phase, 12 heifers successively received doses of 200, 400, 800, and 1600 mg of bromoform orally, separated by a 72-hour washout period. In the second phase, a different cohort of 12 dairy heifers was used. Each heifer received a total of four doses of bromoform separated by a wash-out period of 72 hours. Sequentially the treatments were (for each of the 12 heifers) an oral dose of 50 mg, followed by an IV dose of 50 mg, followed by an oral dose of 100 mg and finally an IV dose of 100 mg.Blood samples were assayed by gas chromatography-mass spectrophotometry for bromoform and dibromomethane to estimate the pharmacokinetic parameters using a non-compartmental analysis. RESULTS: Bromoform was rapidly absorbed as indicated by a short time to the maximum observed concentration of 15 minutes. For the routes of administration and dose ranges investigated, the mean terminal half-life ranged from 0.32 (SE 0.03) hours to 5.73 (SE 1.64) hours when administered orally or IV. With values for the mean area under the curve (AUC) to dose ratio ranging from 0.25 (SE 0.04) to 0.82 (SE 0.19) for oral and 1.39 (SE 0.39) to 4.02 (SE 0.37) for IV administration, bromoform appeared to exhibit non-proportional pharmacokinetic behaviour. The mean absolute bioavailability was 39.13 (SE 10.4)% and 3.36 (SE 0.83)% for 50-mg and 100-mg doses, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Bromoform is rapidly absorbed and exhibits dose dependent elimination kinetics.

Triflate's bigger brother: The unprecedented tribrate anion, [Br3 CSO3 ].

The synthesis of the unprecedented [Br3 CSO3 ]- anion starts with the bromination of phenylmethanesulfonate, C6 H5 OSO2 CH3 , with KOBr leading to C6 H5 OSO2 CBr3 . The formation of the [CBr3 ] moiety has been proved, also by an X-ray structure determination of the compound (triclinic, P-1, a=685.9(2), b=698.1(2), c=1190.2(3) pm, α=93.99(1)°, ß=97.42(1)°, γ=94.45(1)°). The ester C6 H5 OSO2 CBr3 can be split under basic conditions. The resulting acid provides access to the yet unknown tribromomethanesulfates ("tribrates"). K[Br3 CSO3 ] ⋅ H2 O, the first tribrate known so far has been characterized comprehensively, including an X-ray structure determination (monoclinic, C2/c, a=2267.1(2), b=1282.25(8), c=2618.2(2) pm, ß=111.266(2)°), vibrational spectroscopy and theoretical calculations. Moreover, the thermal analysis shows that, after loss of the crystal water, the tribrate decomposes between 530 and 630 K.

Trihalomethanes in drinking water from three First Nation reserves in Manitoba, Canada.

Previous research indicates that the water distribution system used has a significant impact on the microbial quality of tap water sampled in First Nations reserves in Canada. This study tested tap water from homes in three First Nations reserves to compare the concentrations of four trihalomethanes and related water quality parameters between homes receiving piped water from a water treatment plant (WTP) versus homes equipped with cisterns that are filled by a water truck. Of all the samples collected across time from household taps, 75% of piped samples and 70% of cistern samples had TTHM concentrations exceeding Health Canada's maximum acceptable concentration (MAC) of 100 µg L-1 total trihalomethanes (TTHMs) in treated water. In all communities and across sampling times, trichloromethane (CHCl3) was the dominant trihalomethane (42-96%) followed by bromodichloromethane (CHBrCl2) (3-37%) and dibromochloromethane (CHClBr2) (1-18%). Tribromomethane (CHBr3) always accounted for < 5% of TTHMs. Within each of the three First Nations reserves, the water distribution system had no significant effect on TTHM concentration at the household level. Sampling month had a significant effect on TTHM concentration due to temporal changes in dissolved organic carbon of the source water. Results suggest that families in the studied First Nations reserves receive drinking water with high TTHM concentrations and that improvements to the water treatment plant might be the most effective way to minimize trihalomethane formation.

[Proficiency test for determination of tribromomethane in drinking water].

OBJECTIVE: To evaluate the capacity of national laboratories for determination of tribromomethane in drinking water using proficiency testing program. METHODS: The preparation method of the secondary standard materials were used as the reference for the sample preparation in this proficiency testing program. The homogeneity and stability of the samples were tested by single factor analysis of variance( ANOVA) and linear regression. The results provided by participant laboratories were analyzed by robust statistics and assessed using the Z-score. RESULTS: A total of 352 laboratories throughout the country participated in the proficiency testing program. 317 laboratories, or 90. 0% of total participating laboratories, obtained satisfactory results. Results provided by 14 laboratories, or 4. 0% of total participating laboratories, were found to suggest doubts in their capacities. Finally, there were 21 laboratories, constituting 6. 0% of total participating laboratories, with results that were found to be outliers. CONCLUSION: The capacity of national laboratories for determination of tribromomethane in drinking water has been ranked as satisfactory according to statistical analysis of the proficiency testing program results. Only a small portion of the participants require further improvement in their capacities.

Environmental risk appraisement of disinfection by-products (DBPs) in plant model system: Allium cepa.

The organic toxicants formed in chlorinated water cause potential harm to human beings, and it is extensively concentrated all over the world. Various disinfection by-products (DBPs) occur in chlorinated water are genotoxic and carcinogenic. The toxicity is major concern for chlorinated DBPs which has been present more in potable water. The purpose of the work was to evaluate genotoxic properties of DBPs in Allium cepa as a plant model system. The chromosomal aberration and DNA laddering assays were performed to examine the genotoxic effect of trichloroacetic acid (TCAA), trichloromethane (TCM), and tribromomethane (TBM) in a plant system with distinct concentrations, using ethyl methanesulfonate (EMS) as positive control and tap water as negative control. In Allium cepa root growth inhibition test, the inhibition was concentration dependent, and EC50 values for trichloroacetic acid (TCAA), trichloromethane (TCM), and tribromomethane (TBM) were 100 mg/L, 160 mg/L, and 120 mg/L respectively. In the chromosome aberration assay, root tip cells were investigated after 120 h exposure. The bridge formation, sticky chromosomes, vagrant chromosomes, fragmented chromosome, c-anaphase, and multipolarity chromosomal aberrations were seen in anaphase-telophase cells. It was noticed that with enhanced concentrations of DBPs, the total chromosomal aberrations were more frequent. The DNA damage was analyzed in roots of Allium cepa exposed with DBPs (TCAA, TCM, TBM) by DNA laddering. The biochemical assays such as lipid peroxidation, H2O2 content, ascorbate peroxidase, guaiacol peroxidase, and catalase were concentration dependent. The DNA interaction studies were performed to examine binding mode of TCAA, TCM, and TBM with DNAs. The DNA interaction was evaluated by spectrophotometric and spectrofluorometric studies which revealed that TCAA, TCM, and TBM might interact with Calf thymus DNA (CT- DNA) by non-traditional intercalation manner.

Generation of chlorine by-products in simulated wash water.

Free chlorine (FC) reacting with organic matter in wash water promotes the formation of chlorine by-products. This study aims to evaluate the dynamic impact of FC and organic load on the generation of haloacetic acids (HAAs) and trihalomethanes (THMs) in simulated wash water. Lettuce juice was sequentially added into FC solution with FC periodically replenished. Water samples were collected after each lettuce juice addition to measure water qualities and determine HAAs and THMs using US-Environmental-Protection-Agency (EPA) methods. Concentrations of 88-2103 µg/l of total HAAs and 20.79-859.47 µg/l of total THMs were detected during the study. Monobromoacetic, tribromoacetic, chlorodibromoacetic and trichloroacetic acid were the major HAAs components. Chloroform (trichloromethane) was the primary THMs present. A significant correlation of HAAs with chemical oxygen demand and THMs with FC was observed. Results indicated that optimizing wash water sanitizing systems to limit organic matters and maintain minimal effective FC concentration is critical.

A sensitive and fast method for trihalomethanes in urine using gas chromatography-triple quadrupole mass spectrometry.

Because of the plethora of exposure sources and routes through which humans are exposed to trihalomethanes (THM), the limitation of their short half-lives could be overcome, if a highly sensitive method was available to quantify urinary THM concentrations at sub-ppb levels. The objective of this study was to develop a fast and reliable method for the determination of the four THM analytes in human urine. A sensitive methodology was developed for THM in urine samples using gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS/MS) promoting its use in epidemiological and biomonitoring studies. The proposed methodology enjoys limits of detection similar to those reported in the literature (11-80 ng L(-1)) and the advantages of small initial urine volumes (15 mL) and fast analysis per sample (12 min) when compared with other methods. This is the first report using GC-QqQ-MS/MS for the determination of THM in urine samples. Because of its simplicity and less time-consuming nature, the proposed method could be incorporated into detailed (hundreds of participants' urine samples) exposure assessment protocols providing valuable insight into the dose-response relationship of THM and cancer or pregnancy anomalies.