Field efficacy evaluation and post-treatment contamination risk assessment of an ultraviolet disinfection and safe storage system.

Inconsistent use of household water treatment and safe storage (HWTS) systems reduces their potential health benefits. Ultraviolet (UV) disinfection is more convenient than some existing HWTS systems, but it does not provide post-treatment residual disinfectant, which could leave drinking water vulnerable to recontamination. In this paper, using as-treated analyses, we report on the field efficacy of a UV disinfection system at improving household drinking water quality in rural Mexico. We further assess the risk of post-treatment contamination from the UV system, and develop a process-based model to better understand household risk factors for recontamination. This study was part of a larger cluster-randomized stepped wedge trial, and the results complement previously published population-level results of the intervention on diarrheal prevalence and water quality. Based on the presence of Escherichia coli (proportion of households with ≥ 1 E. coli/100 mL), we estimated a risk difference of -28.0% (95% confidence interval (CI): -33.9%, -22.1%) when comparing intervention to control households; -38.6% (CI: -48.9%, -28.2%) when comparing post- and pre-intervention results; and -37.1% (CI: -45.2%, -28.9%) when comparing UV disinfected water to alternatives within the household. We found substantial increases in post-treatment E. coli contamination when comparing samples from the UV system effluent (5.0%) to samples taken from the storage container (21.1%) and drinking glasses (26.0%). We found that improved household infrastructure, additional extractions from the storage container, additional time from when the storage container was filled, and increased experience of the UV system operator were associated with reductions in post-treatment contamination. Our results suggest that the UV system is efficacious at improving household water quality when used as intended. Promoting safe storage habits is essential for an effective UV system dissemination. The drinking glass appears to represent a small but significant source of recontamination that is likely to impact all HWTS systems

AGENTES ASOCIADOS Y SU PAPEL EN LA DECLINACIÓN Y MUERTE DE ENCINOS (QUERCUS, FAGACEAE) EN EL CENTRO-OESTE DE MÉXICO

This study was carried out to identify bioticand abiotic agents and to determine theirrole in oak decline and death in five statesof the Mexican Republic: Aguascalientes,Colima, Guanajuato, Jalisco and Nayarit.Two 0.1-ha permanent plots wereestablished at the most representativeforested areas with tree death, diebackand bleeding cankers in these statesand sampled during 2003, 2004 and 2005(10 plots in total). Field observations weremade, and foliage, branch, trunk and soilsamples were collected to identify theassociated agents in each plot. Isolates frombleeding cankers were made in situ. Themost commonly found biotic agents were:Phytophthora cinnamomi, Pythium sp.,Hypoxylon antropunctatum, Ganodermaspp., Armillaria sp., Apiognomoniaquercina, the dwarf mistletoe(Phoradendron villosum), bark borers,insect defoliators and livestock overgrazing.Among the abiotic stress factors commonlyfound were the effects due to lowtemperature-lack of water and fire. Basedon their incidence, P. cinnamomi, H.antropunctatum and low temperature-lackof water were considered the most importantcontributors to the decline and death of theoaks. P. cinnamomi was identified in four ofthe 10 plots, mainly in Colima and Jalisco;H. antropunctatum was detected in sixplots, particularly in Nayarit andAguascalientes. Stem cankers (cracks) dueto low temperature-lack of water wereobserved in four plots, damaging 52% of the trees in Aguascalientes and 24% inGuanajuato. It was concluded that P.cinnamomi is killing some oak species, H.antropunctatum is colonizing weakenedtrees, and low temperature-lack of water iscausing stress and in some cases death inoaks.Este estudio tuvo como objetivo identificary determinar el papel tanto de los factoresbióticos como de los abióticos asociados ala declinación y muerte del encino en cincoestados de la República mexicana: Aguascalientes, Colima, Guanajuato, Jalisco yNayarit. Para esto, se establecieron dossitios permanentes de 0.1 ha en cada una delas áreas más representativas (con arboladomuerto, con muerte regresiva y cancros conexudado) de los estados mencionados (10sitios en total), los cuales fueron muestreados durante 2003, 2004 y 2005. Sehicieron observaciones y colectas en campode follaje, ramas, tronco y suelo, paraidentificar a los diferentes agentes de dañoen cada sitio. Se realizaron aislamientosin situ de cancros con exudado en mediosespecíficos. Los agentes bióticos máscomunes fueron: Phytophthora cinnamomi,Pythium sp., Hypoxylon antropunctatum,Ganoderma sp., Armillaria sp.,Apiognomonia quercina, el muérdagoenano (Phoradendron villosum), barrenadores, defoliadores y sobrepastoreo. Entre los abióticos causantes de estrés ymuerte, destacaron los daños ocasionadospor las bajas temperaturas-falta de aguay fuego. Con base en su incidencia, P.cinnamomi, H. antropunctatum y las bajastemperaturas-falta de agua son considerados los factores de mayor importanciaen la declinación y muerte del encino. P.cinnamomi fue identificado en cuatro delos diez sitios, particularmente de Colimay Jalisco; H. antropunctatum fué detectadoen seis de diez, principalmente en losrodales de Nayarit y Aguascalientes. Loscancros de troncos (rajaduras), debido a lasbajas temperaturas-falta de agua, seobservaron en cuatro sitios, afectando al52% de los árboles en Aguascalientes y24% en Guanajuato. Se concluye que P.cinnamomi está ocasionando la muertede algunas especies de encino, H.antropunctatum está coloni-zando árbolesdebilitados y las bajas temperaturas-faltade agua están participando como agentescausantes de estrés y muerte en algunoscasos

Assessment of a low-cost, point-of-use, ultraviolet water disinfection technology.

We describe a point-of-use (POU) ultraviolet (UV) disinfection technology, the UV Tube, which can be made with locally available resources around the world for under $50 US. Laboratory and field studies were conducted to characterize the UV Tube's performance when treating a flowrate of 5 L/min. Based on biological assays with MS2 coliphage, the UV Tube delivered an average fluence of 900+/-80 J/m(2) (95% CI) in water with an absorption coefficient of 0.01 cm(-1). The residence time distribution in the UV Tube was characterized as plug flow with dispersion (Peclet Number = 19.7) and a mean hydraulic residence time of 36 s. Undesirable compounds were leached or produced from UV Tubes constructed with unlined ABS, PVC, or a galvanized steel liner. Lining the PVC pipe with stainless steel, however, prevented production of regulated halogenated organics. A small field study in two rural communities in Baja California Sur demonstrated that the UV Tube reduced E. coli concentrations to less than 1/100 ml in 65 out of 70 samples. Based on these results, we conclude that the UV Tube is a promising technology for treating household drinking water at the point of use

Measuring User Compliance and Cost Effectiveness of Safe Drinking Water Programs: A Cluster-Randomized Study of Household Ultraviolet Disinfection in Rural Mexico.

Low adoption and compliance levels for household water treatment and safe storage (HWTS) technologies have made it challenging for these systems to achieve measurable health benefits in the developing world. User compliance remains an inconsistently defined and poorly understood feature of HWTS programs. In this article, we develop a comprehensive approach to understanding HWTS compliance. First, our Safe Drinking Water Compliance Framework disaggregates and measures the components of compliance from initial adoption of the HWTS to exclusive consumption of treated water. We apply this framework to an ultraviolet (UV)-based safe water system in a cluster-randomized controlled trial in rural Mexico. Second, we evaluate a no-frills (or "Basic") variant of the program as well as an improved (or "Enhanced") variant, to test if subtle changes in the user interface of HWTS programs could improve compliance. Finally, we perform a full-cost analysis of both variants to assess their cost effectiveness (CE) in achieving compliance. We define "compliance" strictly as the habit of consuming safe water. We find that compliance was significantly higher in the groups where the UV program variants were rolled out than in the control groups. The Enhanced variant performed better immediately postintervention than the Basic, but compliance (and thus CE) degraded with time such that no effective difference remained between the two versions of the program

UVC inactivation of MS2-phage in drinking water – Modelling and field testing

UVC disinfection has been recognised by the WHO as an effective disinfection treatment to provide decentralized potable water. Under real conditions there are still unknowns that limit this application including the influence of suspended solids and natural organic matter. This work aims to investigate the influence of two key parameters, suspended solids and natural organic matter, on the efficiency of UVC disinfection of surface water to achieve the drinking water quality requirements established by the WHO for point of use (POU) technologies. Kaolinite (turbidity agent) and humic acids (HA, model of organic matter) were used in a factorial design of experiments (Turbidity from 0 to 5 NTU, and HA from 0 to 3.5 mg/L) to investigate their effect on UVC inactivation of MS2 phage in surface water. A collimated beam (12 W) and a commercial UVC disinfection flow system (16 W) designed to provide drinking water at households were used. The UVC flow system both in the laboratory and in the field was able to achieve the reduction requirements established by WHO (LRV >3.5 for all tested conditions), confirming the good performance of the studied UVC disinfection system. The results found in the lab were used to establish a numerical model that predicts the disinfection rate constant as a function of water turbidity and transmittance at 254 nm (confidence level>95%). The model permitted to elucidate the critical effect of low concentrations of HA in reducing the inactivation rate by 40% for 3.5 mg/L-HA compared with 0, the non-significant detrimental effect of turbidity lower than 5 NTU, and the lack of synergistic effects between both parameters at these levels. The UVC flow system was also tested in the field, in Tzabalho, Chiapas (Mexico), and Antioquia (Colombia), with spiked MS2 into natural surface water. This investigation opens a potential application to monitor the performance of UVC systems with surface water by monitoring transmittance at 254 nm as a tool to control UVC domestic systems to deliver safe drinking water in a household without the need of expensive and laborious biological monitoring tools

Agentes asociados y su papel en la declinación y muerte de encinos (quercus, fagaceae) en el centro-oeste de México

ABSTRACT This study was carried out to identify biotic and abiotic agents and to determine their role in oak decline and death in five states of the Mexican Republic: Aguascalientes, Colima, Guanajuato, Jalisco and Nayarit. Two 0.1-ha permanent plots were established at the most representative forested areas with tree death, dieback and bleeding cankers in these states and sampled during 2003, 2004 and 2005 (10 plots in total). Field observations were made, and foliage, branch, trunk and soil samples were collected to identify the associated agents in each plot. Isolates from bleeding cankers were made in situ. The most commonly found biotic agents were: Phytophthora cinnamomi, Pythium sp., Hypoxylon antropunctatum, Ganoderma spp., Armillaria sp., Apiognomonia quercina, the dwarf mistletoe (Phoradendron villosum), bark borers, insect defoliators and livestock overgrazing. Among the abiotic stress factors commonly found were the effects due to low temperature-lack of water and fire. Based on their incidence, P. cinnamomi, H. antropunctatum and low temperature-lack of water were considered the most important contributors to the decline and death of the oaks. P. cinnamomi was identified in four of the 10 plots, mainly in Colima and Jalisco; H. antropunctatum was detected in six plots, particularly in Nayarit and Aguascalientes. Stem cankers (cracks) due to low temperature-lack of water were observed in four plots, damaging 52% of the trees in Aguascalientes and 24% in Guanajuato. It was concluded that P. cinnamomi is killing some oak species, H. antropunctatum is colonizing weakened trees, and low temperature-lack of water is causing stress and in some cases death in oaks.RESUMEN Este estudio tuvo como objetivo identificar y determinar el papel tanto de los factores bióticos como de los abióticos asociados a la declinación y muerte del encino en cinco estados de la República mexicana: Aguascalientes, Colima, Guanajuato, Jalisco y Nayarit. Para esto, se establecieron dos sitios permanentes de 0.1 ha en cada una de las áreas más representativas (con arbolado muerto, con muerte regresiva y cancros con exudado) de los estados mencionados (10 sitios en total), los cuales fueron muestreados durante 2003, 2004 y 2005. Se hicieron observaciones y colectas en campo de follaje, ramas, tronco y suelo, para identificar a los diferentes agentes de daño en cada sitio. Se realizaron aislamientos in situ de cancros con exudado en medios específicos. Los agentes bióticos más comunes fueron: Phytophthora cinnamomi, Pythium sp., Hypoxylon antropunctatum, Ganoderma sp., Armillaria sp., Apiognomonia quercina, el muérdago enano (Phoradendron villosum), barrenadores, defoliadores y sobrepastoreo. Entre los abióticos causantes de estrés y muerte, destacaron los daños ocasionados por las bajas temperaturas-falta de agua y fuego. Con base en su incidencia, P. cinnamomi, H. antropunctatum y las bajas temperaturas-falta de agua son considerados los factores de mayor importancia en la declinación y muerte del encino. P. cinnamomi fue identificado en cuatro de los diez sitios, particularmente de Colima y Jalisco; H. antropunctatum fué detectado en seis de diez, principalmente en los rodales de Nayarit y Aguascalientes. Los cancros de troncos (rajaduras), debido a las bajas temperaturas-falta de agua, se observaron en cuatro sitios, afectando al 52% de los árboles en Aguascalientes y 24% en Guanajuato. Se concluye que P. cinnamomi está ocasionando la muerte de algunas especies de encino, H. antropunctatum está coloni-zando árboles debilitados y las bajas temperaturas-falta de agua están participando como agentes causantes de estrés y muerte en algunos casos

"Modernidad" y polarización de la salud en México. Condiciones de vida de los trabajadores y sus familias "Modernity" and polarization of health in Mexico. Living conditions for workers and their families

Se analizan las características del proceso de modernización en México y el deterioro y polarización que ha producido en las condiciones de vida y salud de la población general y de los trabajadores y sus familias. Para ello se muestran diversos indicadores socioeconómicos y de salud. Respecto a la morbilidad, las enfermedades infecciosas ocupan un porcentaje muy elevado, pero otros fenómenos como diabetes, cirrosis hepática, infarto cardiaco, tumores malignos y accidentes y violencias son también serios problemas de salud pública. En regiones del país con características socioeconómicas bien diferenciadas, como los estados de Chiapas y Nuevo León, la polarización de la salud resulta más evidente aún. Por otra parte, el deterioro de las condiciones laborales y la información existente respecto a la salud de los trabajadores, a pesar de sus limitaciones, indican que los trabajadores deben ser considerados como un grupo prioritario. Se muestra el comportamiento paradójico de los accidentes y enfermedades laborales objetos de compensación, con menos accidentes pero más graves, y detección de enfermedades en grados muy avanzados, así como diferencias significativas en la morbilidad laboral en distintas ramas de la producción manufacturera.<br>This article analyzes the characteristics of the modernization process in Mexico and the polarization produced in living and health conditions for the general population as well as workers and their families. We studied socioeconomic and health indicators for this purpose. Infectious diseases occupy a high percentage of general morbidity, yet diseases such as diabetes, hepatic cirrhosis, myocardial infarction, malignant tumors, and accidents and violence are also serious public health problems as causes of morbidity and mortality. In some regions of the country with specific socioeconomic characteristics, polarization of health conditions is even more evident, as in the state of Chiapas as compared to Nuevo León. Deterioration of working conditions and available data on workers' health indicate that the latter should be considered a priority group for health measures. Such data also show the paradoxical trend of the more severe but less frequent work-related accidents and diseases that are subject to compensation as compared to the detection of chronic work-related diseases at an advanced stage, as well as significant differences in occupational morbidity among different branches of manufacturing

Social Inequality, Technological Inequality and Educational Heterogeneity in the Light of the Conectar Igualdad OLPC Programme (Salta, Argentina, 2015–2017)

Does the level of promotion and protection of education have any relation to the level of technological development of society? Is there any correlation between digital and social inequalities when it comes to the rights to education in social and geographical marginalized areas? This chapter bridges both questions answering them via quantitative and qualitative data referred to a specific context, on a specific educative policy: the Conectar Igualdad Programme as a social policy applied in an urban and a rural secondary school located in Salta (Argentina). This case study provides evidence on digital-inequality issues facing adolescent citizens among marginalized communities and promotes evidence-informed policy change for the improvement of the access, the use and the implementation of information and communications technologies (ICTs) for educational, social and cultural development.Fil: García Vargas, Alejandra. Universidad Nacional de Jujuy. Centro Interdisciplinario de Investigaciones en Tecnologías y Desarrollo Social para el Noa. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta-Jujuy. Centro Interdisciplinario de Investigaciones en Tecnologías y Desarrollo Social para el Noa; Argentina. Universidad Nacional de Jujuy. Facultad de Humanidades y Ciencias Sociales; ArgentinaFil: Golovanevsky, Laura Andrea. Universidad Nacional de Jujuy. Centro Interdisciplinario de Investigaciones en Tecnologías y Desarrollo Social para el Noa. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta-Jujuy. Centro Interdisciplinario de Investigaciones en Tecnologías y Desarrollo Social para el Noa; ArgentinaFil: Chachagua, Maria Rosa. Universidad Nacional de Jujuy. Centro Interdisciplinario de Investigaciones en Tecnologías y Desarrollo Social para el Noa. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta-Jujuy. Centro Interdisciplinario de Investigaciones en Tecnologías y Desarrollo Social para el Noa; Argentina. Universidad Nacional de Jujuy. Facultad de Humanidades y Ciencias Sociales; Argentin