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In the present study, we applied an ultrafiltration process to detectBlastocystisspp.,Cryptosporidium parvum,Giardia lambliaand helminth ova during a dry season with cold and warm periods. Samples of wastewater, reuse water for the irrigation of green areas and groundwater were collected on the campus of the National Autonomous University of Mexico. Physicochemical parameters were measured.Blastocystisspp. and its subtypes (ST) were identified using polymerase chain reaction (PCR) and indirect immunofluorescence (IFA);G. lambliaandC. parvumwere identified using IFA, and helminth ova were searched for using flotation/sedimentation and microscopic observation.BlastocystisST3,C. parvumandG. lambliawere detected in wastewater and reuse water, but onlyG. lambliawas detected in all of the samples of reuse water. Helminth ova were not detected. Statistical analysis showed a dependency between total dissolved solids and protozoa. Our data suggest thatG. lambliadetection can be performed as part of reuse water quality assessments for irrigation systems. [ABSTRACT FROM PUBLISHER]

Examines the presence of disinfection byproducts and microorganisms in drinking water in Southeastern Mexico City, Mexico. Analysis of bacterial indicators, physiochemical parameters, and trihalomethane levels; Presence of indicator bacteria and enterobacteria; Implications of water treatment and distribution.

The overall objective of this study is to promote the development of environmental health indicators in Mexico City. Specific examples focused on water quality, household characteristics e.g., sanitation and risk of enteric diseases. A geographic information system (GIS) was used in order to identify eligible wells and their surrounding homesteads (0.5 km around each well). A pilot study was conducted during the rainy season (1999), and a total of 1, 250 eligible households were visited on a random sample basis; only those having children under 5 years of age were interviewed. Data on diarrheal disease (i.e. occurrence in the previous two weeks) were obtained from 950 children, and their guardians provided information on their water supply, sanitation and socioeconomic variables. A total of 320 water samples were obtained from 40 wells, and tested for Total coliforms (TC/100 ml), Fecal coliforms (FC/100 ml). Escherichia coli (EC) and Fecal streptococci (FS). Bacterial indicators were detected in 40% of the wells in the western zone and in 32% of the southern zone (p = 0.01). The rate of diarrheal diseases was higher for children from the southern areas than in the west (OR = 1.7 and 95% CI: 0.99, 2.86). The final analysis showed a higher risk of diarrhea in children from rented homes than those living in owned dwellings (OR = 1.7 and 95% Cl: 1.04, 2.77): the risk was also highest for children living in houses with poor sanitation facilities (e.g., latrine) than those connected to a sewerage (OR = 1.7 and 95% Cl: 1.00, 2.93). Children from households perceiving unpleasant taste of water showed a higher risk than those without complaints (OR = 2.2 and 95% Cl: 1.28, 3.75). Linkages between environmental factors and health risk were created from spatially distributed information, and the proposed environmental health indicator (EHI) summarized the most significant predictors of diarrheal diseases. This baseline information may contribute to further environmental health investigation and policy making analysis. [ABSTRACT FROM AUTHOR]

Looks at how the increase of rural populations of Third World countries has reshsped the thrid world. Phenomenon of urban concentrations and centralism; World's population statistics; Location of Mexico City; Population and land use; Water management; Treatment for wastewater; Quality of air. INSET: Cycles of population growth and decline in the Basin of Mexico..