Exposure level and health risk assessment of chlorination disinfectant by-products in drinking water in Xiangyang City / 公共卫生与预防医学

Objective To understand the exposure level of disinfection by-products (DBPs) in drinking water in Xiangyang City and to evaluate the health risks of the population, so as to provide reference for the safety risk control of drinking water. Methods Sampling and laboratory testing were conducted according to national standard methods. The risk assessment model provided by USEPA was used to evaluate the health risks. Results Trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and tribromomethane (TBM) were detected in drinking water in Xiangyang City. The contents of halogenated hydrocarbon DBPs in water disinfected with liquid chlorine were higher than those with chlorine dioxide. The contents of three DBPs were higher in wet season than those in dry season except TBM. The content of TCM in pipe network terminal water and secondary water supply disinfected with chlorine dioxide was higher than that in factory water. The carcinogenic risk of DBPs in drinking water disinfected with liquid chlorine was 4.33×10-5, and the non-carcinogenic risk was 0.114. The carcinogenic risk of DBPs in drinking water disinfected with chlorine dioxide was 1.24×10-6, and the non-carcinogenic risk was 3.15×10-3. Conclusion The health risk of DBPs in drinking water in Xiangyang City is acceptable, but TCM produced by liquid chlorine disinfection should be paid more attention. It is recommended that chlorine dioxide disinfection be used to reduce the health risks of halogenated hydrocarbon DBPs.

Echocardiographic Assessment of Mitral Valve Regurgitation / 대한내과학회지

Mitral regurgitation (MR) is defined as the reflux of blood from the left ventricle into the left atrium during systole, resulting from the loss of adequate closure of the mitral valve. Echocardiography has become the primary noninvasive imaging method for evaluating mitral valvular regurgitation, since it provides structural and hemodynamic information. The echocardiographic assessment of mitral regurgitation should quantify the regurgitation, assess the valve anatomy and function, and evaluate the consequences of mitral regurgitation on the cardiac chambers. In clinical practice, the management of patients with mitral regurgitation is based largely on the echocardiography results. This article describes the echocardiographic assessment of mitral regurgitation, emphasizing the usefulness of echocardiography in primary care.