Biomonitoring of Bromine-Containing Trihalomethanes in the Pregnant Women: Urinary Levels and Association with Lifestyle Factors

Abstract 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.