Sustainable and effective control of trihalomethanes in the breakpoint chlorination of wastewater effluents.

The control of trihalomethanes (THMs) in waters subjected to chlorination is essential for protecting public health. However, the necessary means are not always available, especially in developing countries and regions. Under circumstances of scarce resources, one can utilize various means available for the control of THMs: a simple and affordable analytical method for testing of THMs, the study of the parameters tested routinely that could be used as indicators and the dose of chlorine used for the chlorination process. The objective of this work was to study the potential formation of THMs in wastewater effluents using a simple method of detection and various doses of chlorine in relation to the breakpoint and to validate some commonly determined parameters as indicators of THM formation. THM concentrations were measured using a simple spectrophotometric method based on the Fujiwara reaction. To determine the chlorine demand, a super-chlorination was performed and free and residual chlorine was measured; the mean value of chlorine demand was 166.6 mgCl2/L. The chlorination with concentrations well below the chlorine demand produces a significant reduction in microbial content. With regard to the formation of THMs the higher the dose of chlorine added, the higher the concentration of THMs. In relation to commonly determined parameters our data only provide a logarithmic linear regression between THMs and ammonium. According to our results, the breakpoint must be determined for the chlorination of sewage and their effluents, and chlorination should be performed with concentrations of chlorine at approximately 1/3 of the demand.

[Construction and validation of a questionnaire to measure behavior, knowledge and attitudes on hand hygiene in health personnel training]. / Construcción y validación de un cuestionario para medir conductas, conocimientos y actitudes sobre la higiene de las manos en personal sanitario en formación.

BACKGROUND: Hand hygiene in the health context is a complex behaviour. There have been rarely given the role of the knowledge and attitudes as predictors of hand hygiene behaviour. The main objective of this work is the description of the development of a questionnaire on hand hygiene and the analysis of their measurement properties. METHOD: An instrument which was designed and validated a questionnaire. It was held in January 2009. It finally has had 50 items that assess risk behaviour intention before and after contact with the patient, declarative knowledge and attitudes about hand hygiene. It has been applied to 431 students of health sciences at the University of Granada. RESULTS: There were three factor analysis, ultimately obtaining a general convergence value that explains 46.01% of the total variance and high reliability (a = 0,843). There is correlation between knowledge and behavior intentions before and after patient contact (p < 0.01).In turn, the attitude correlates only with behavioral intention before (p < 0.05). The hand hygiene behavior refers to a higher mean after the completion of various health activities before the same (4.26 and 3.96 respectively). Both declarative knowledge and attitudes significantly predict behavioral intention, in particular the conduct before the contact with the patient (R² = 0.100, standardized Beta 0.256 for knowledge and 0.145 for attitudes). CONCLUSIONS: The questionnaire shows high internal consistency. We have obtained a valid tool for assessing risk behavior, knowledge and attitudes about students' hand hygiene in health sciences. The tool detects deficiencies in basic skills in students.

Environmental tobacco smoke exposure in children: parental perception of smokiness at home and other factors associated with urinary cotinine in preschool children.

Parental smoking behavior at home and sociodemographic variables may influence exposure to environmental tobacco smoke (ETS) in children. A sample of 115 preschool children aged 3-6 years was enrolled in this study. ETS exposure was evaluated through a questionnaire about parents' smoking behavior and determinations of urinary cotinine -- a biomarker of exposure -- in children. Bivariate and multiple regression analyses were used to evaluate the association between the smoking behavior of each parent at home, sociodemographic factors and cotinine levels in children. The parental perception of smokiness in the home was significantly associated with urinary cotinine in children (r-partial coefficient=0.324; P<0.002). The father's education, mother's smoking status, and day of the week when urine was sampled (Tuesday) were also independently associated with levels of cotinine. These four variables explained 26.4% of the variance in the cotinine levels of children. In designing educational programs to reduce passive smoking among children, it is necessary to take into account those factors related with cotinine levels in children. Our results support the influence of the mothers' smoking status, the fathers' educational level, and the day of the week of sampling on cotinine in children. The perception of parents (smokers and nonsmokers) about the smokiness in the home could also be a useful indicator of the cotinine in children exposed to environmental tobacco smoke in the household.