Trihalomethanes containing bromine (Br-THMs) are compounds formed from the reaction of organic and inorganic substances in drinking water with chlorine as a common disinfectant. Epidemiological evidence indicated various outcomes as a result of long-term exposure to these compounds. This study aims to investigate the concentration of urinary Br-THMs in a sample of third-trimester pregnant women and to determine its correlation with lifestyle factors. This cross-sectional study was conducted among 118 pregnant women in Isfahan, Iran. The third-trimester urine Br-THMs including dibromochloromethane (DBCM), bromodichloromethane (BDCM), and broomcorn (TBM) were measured using solid-phase micro-extraction gas chromatography. The distribution of urinary Br-THMs concentration was positively skewed then these variables were subjected to logarithmic transformation. Spearman ranks correlation coefficient, and two independent samples t-test were used to assess the association of urinary Br-THMs concentration with its demographic and lifestyle determinants.The findings showed that the mean (SD) concentrations of DBCM, BDCM, TBM and brominatede THMs were 14.76 (27.17), 10.25 (11.37), 4.96 (3.21) and 30.17 (40.80) ng/L, respectively. In addition, significant inverse correlation was found between the use of water storage tanks and Br-THMs (DBCM, BDCM, TBM and brominatede THMs, P-value = 0.005, 0.019, >0.001 and 0.007 < 0.05, respectively).In this study, among the quantitative and qualitative variables, the use of storage tanks had an inverse correlation with Br-THMs. In addition, the status of urinary concentration of Br-THMs in pregnant women was less than in the other countries in the same area. Improving water quality and using modern methods to eliminate disinfection by-products as well as improving lifestyle patterns are efficient methods to reduce exposure to these contaminants.

Atenolol (ATN) is a β-blocker drug extensively used to treat arrhythmias and high blood pressure. Because the human body cannot metabolize it completely, this drug has been commonly found in many environmental matrices. In the present study, the response surface method (RSM) was used for adsorption prediction of ATN on modified multiwalled carbon nanotubes (M-MWCNTs) by NaOCl and ultrasonic. The sensitivity analysis was done by the Monte Carlo method. Sensitivity analysis was performed to determine the effective parameter by the Monte Carlo simulator. Statistical analysis of variance (ANOVA) was performed by using the nonlinear second-order model of RSM. The influential parameters including contact time (min), adsorbent dosage (g/L), pH, and the initial concentration (mg/L) of ATN were investigated, and optimal conditions were determined. Kinetic of ATN adsorption on M-MWCNTs was evaluated using pseudo-first, pseudo-second-order, and intraparticle diffusion models. Equilibrium isotherms for this system were analyzed by the ISOFIT software. As per our result, optimum conditions in the adsorption experiments were pH 7, 60 min of contact time, 0.5 mg/L ATN initial concentration, and 150 mg/L adsorbent dose. In terms of ATN removal efficiency, coefficients of R2 and adjusted R2 were 0.999 and 0.998, respectively. Sensitivity analysis also showed that contact time has the greatest effect on increasing the removal of ATN. Pseudo-first-order (R2 value of 0.99) was the best kinetic model for the adsorption of ATN, and for isotherm, BET (AICC value of 3.27) was the best model that fit the experimental data. According to the obtained results from sensitive analysis, time was the most important parameter, and after that, the adsorbent dose and pH affect positively on ATN removal efficiency. It can be concluded that the modified multiwalled carbon nanotubes can be applied as one of the best adsorbents to remove ATN from the aqueous solution.

Background: Chlorination of wastewater effluent with high levels of residual organic matter has been suspected to the production of toxic and hazardous disinfection by-products (DBPs) including trihalomethane (THM) compounds. Methods: In this study, two rapid techniques including dissolved oxygen depletion (DOD) and optical density (OD) bioassays were used to evaluate the chloroform toxicity of aqueous solution. The activated sludge was collected from aeration tank of a full-scale municipal wastewater treatment plant and used as a biological inoculum. In order to achieve an active and stabilized mixed culture of bacteria, the test cultures were transferred to a fresh nutrient broth culture media every day. The influence of chloroform on DOD and OD bioassays was examined at chloroform initial concentrations of 10-1000 µg/L. Results: It was revealed that the application of chloroform at concentrations of 100 and 1000 µg/L showed moderate and extreme toxicity, respectively, and reduced bacterial activity. The estimated chemical concentration with 50% inhibition of bacterial activity for DOD and OD bioassays was 457 and 961 µg/L, respectively. Conclusion: According to the results, the wastewater effluent should use bioassays in order to evaluate the effects of DBPs where the wastewater effluent is disinfected by chlorine compounds.

No abstract