Water quality issues and infant diarrhoea in a South American province

A Simple Method for Identifying Appropriate Areas for Onsite Wastewater Treatment

Onsite Domestic Wastewater Treatment Systems (ODWTS) are increasingly important for treating domestic wastewater in metropolitan contexts, especially in suburban sectors isolated from sewer networks and centralized treatment plants. When ODWTS are not correctly planned and located in suitable places, or are not properly designed, they can cause groundwater contamination and generate risks for human health. This work presents a Spatial Decision Support System (SDSS) to zone specific areas based on a few simple parameters. The proposed tool can be easily adapted to different contexts, even where institutional capacities are low. Results obtained in the metropolitan area of the Lerma Valley (Salta, Argentina) show strong contradictions between our zoning and current urbanization features in the study area. As a result, environmental impacts and health hazards are likely to manifest in the short or medium term. The sectors with the best receptivity conditions were found in the southern sector of the study area. We argue that ODWTS can be safely implemented in many areas as long as this concept is embedded in urban planning initiatives, which usually also require the consolidation or development of appropriate institutions and control systems.

Inequality in access to improved drinking water sources and childhood diarrhoea in low- and middle-income countries

In addition to the conventional wisdom of categorizing countries based on nationally-averaged coverage in access to improved drinking water sources (IDWS), this study incorporated sub-national inequality into a novel categorisation framework. The association between access to IDWS and the incidence of childhood diarrhoea (ICD) was also quantified. Information from 1.63 million households obtained through nationally representative and cross-sectional demographic and health survey (DHS) and multiple indicator cluster survey (MICS) from 81 countries were analysed. Sub-national inequalities in the access to IDWS were measured using proportional variability (PV). Most studied countries with low coverage and high inequalities in accessing IDWS were from Sub-Saharan Africa (SSA). Wealth status of households showed a higher variability in the IDWS than the variability across locations. Significant negative associations between accessing IDWS and ICD were observed for regional models, except for SSA. This study adds knowledge towards understanding the state of sustainable development goal achievements in terms of accessing IDWS. The knowledge may be helpful in designing country-specific, achievable, short- and long-term strategies. The non-decisive relation between access to IDWS and ICD indicates the adoption of additional measures in the modelling mechanism.

Effect of Neighborhood Sanitation Coverage on Fecal Contamination of the Household Environment in Rural Bangladesh

Enteric pathogens can be transmitted within the household and the surrounding neighborhood. The objective of this study was to understand the effect of neighborhood-level sanitation coverage on contamination of the household environment with levels of fecal indicator bacteria in rural Bangladesh. We conducted spot-check observations of sanitation facilities in neighboring households (NHs) within a 20-m radius of target households with children aged 6-24 months. Sanitation facilities were defined as improved (a private pit latrine with a slab or better) or unimproved. Fecal coliforms (FCs) on children's hands and sentinel toy balls were measured and used as indicators of household-level fecal contamination. We visited 1,784 NHs surrounding 428 target households. On average, sentinel toy balls had 2.11(standard deviation [SD] = 1.37) log₁₀ colony-forming units (CFUs) of FCs/toy ball and children's hands had 2.23 (SD = 1.15) log₁₀ CFU of FCs/two hands. Access to 100% private improved sanitation coverage in the neighborhood was associated with a small and statistically insignificant difference in contamination of sentinel toy balls (difference in means = -0.13 log₁₀ CFU/toy ball; 95% confidence intervals [CI]: -0.64, 0.39; P = 0.63) and children's hands (difference in means = -0.11 log₁₀ CFU/two hands; 95% CI: -0.53, 0.32; P = 0.62). Improved sanitation coverage in the neighborhood had limited measurable effect on FCs in the target household environment. Other factors such as access to improved sanitation in the household, absence of cow dung, presence of appropriate water drainage, and optimal handwashing practice may be more important in reducing FCs in the household environment.

Development of a relative risk model for drinking water regulation and design recommendations for a peri urban region of Argentina

Argentina is a developing Latin American nation that has an aim of achieving the United Nations Millennium Development Goals for potable water supplies. Their current regulations however, limit the continued development of improved potable water quality and infrastructure from a microbiological viewpoint. This is since the current regulations are focused solely to pathogenic Eschericia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and fecal indicators. Regions of lower socioeconomic status such as peri-urban areas are particularly at risk due to lessened financial and political ability to influence their environmental quality and infrastructure needs. Therefore, a combined microbiological sampling, analysis and quantitative microbial risk assessment (QMRA) modeling effort were engaged for a peri-urban area of Salta Argentina. Drinking water samples from home taps were analyzed and a QMRA model was developed, results of which were compared against a general 1:10,000 risk level for lack of a current Argentinian standard. This QMRA model was able to demonstrate that the current regulations were being achieved for E. coli but were less than acceptable for P. aeruginosa in some instances. Appropriate health protections are far from acceptable for Giardia for almost all water sources. Untreated water sources were sampled and analyzed then QMRA modeled as well, since a significant number of the community (∼9%) still use them for potable water supplies. For untreated water E. coli risks were near 1:10,000, however, P. aeruginosa and Giardia risks failed to be acceptable in almost all instances. The QMRA model and microbiological analyses demonstrate the need for improved regulatory efforts for the peri-urban area along with improved investment in their water infrastructure.

Strategies to optimize monitoring schemes of recreational waters from Salta, Argentina: a multivariate approach

Several recreational surface waters in Salta, Argentina, were selected to assess their quality. Seventy percent of the measurements exceeded at least one of the limits established by international legislation becoming unsuitable for their use. To interpret results of complex data, multivariate techniques were applied. Arenales River, due to the variability observed in the data, was divided in two: upstream and downstream representing low and high pollution sites, respectively, and cluster analysis supported that differentiation. Arenales River downstream and Campo Alegre Reservoir were the most different environments, and Vaqueros and La Caldera rivers were the most similar. Canonical correlation analysis allowed exploration of correlations between physicochemical and microbiological variables except in both parts of Arenales River, and principal component analysis allowed finding relationships among the nine measured variables in all aquatic environments. Variable's loadings showed that Arenales River downstream was impacted by industrial and domestic activities, Arenales River upstream was affected by agricultural activities, Campo Alegre Reservoir was disturbed by anthropogenic and ecological effects, and La Caldera and Vaqueros rivers were influenced by recreational activities. Discriminant analysis allowed identification of subgroup of variables responsible for seasonal and spatial variations. Enterococcus, dissolved oxygen, conductivity, E. coli, pH, and fecal coliforms are sufficient to spatially describe the quality of the aquatic environments. Regarding seasonal variations, dissolved oxygen, conductivity, fecal coliforms, and pH can be used to describe water quality during dry season, while dissolved oxygen, conductivity, total coliforms, E. coli, and Enterococcus during wet season. Thus, the use of multivariate techniques allowed optimizing monitoring tasks and minimizing costs involved.

Increasing capacity for environmental engineering in Salta, Argentina

BACKGROUND

The Fogarty International Center (FIC) of the United States National Institutes of Health includes the International Training and Research in Environmental and Occupational Health (ITREOH) Program. The "International Training Program in Environmental Toxicology and Public Health" Center, funded in 2002 is based at the University of California, Davis, and is part of the ITREOH group of Centers. It has major efforts focused at the public universities in Montevideo, Uruguay, and Salta, Argentina.

RESULTS

Training and research efforts in Salta begun in 2005 in the College of Engineering. A donated used real-time PCR machine was the starting point and the initial FIC support was instrumental to face other problems including physical space, research projects and grants, trainees, training, networking, and distractions/opportunities in order to develop local capacities in Environmental Engineering using modern methodology. After 6 years of successful work, the Salta center has become a reference Center in the field, and is still growing and consolidating.

CONCLUSIONS

This program has had a significant impact locally and regionally. The model used in Argentina could be easily adapted to other fields or types of projects in Argentina and in other developing countries.