Methodology for assessment of drinking water quality in Ciudad Romero, Bajo Lempa region, El Salvador
Roberto Mejía, Alexandre Ribó , David Alfaro, Edgar Quinteros, Lilian Nuñez, Alejandro López, Carlos M. Orantes, Dina L. López
National Institute of Health, Ministry of Health of El Salvador
Presentation: Video available since 23.08.2014, [Video]
Discussion: 26.08.2014, [Discussion]
The National Institute of Health of Ministry of Health of El Salvador has developed a methodology to evaluate pollution exposition in areas where the population lives close to crop fields where massive use of agrochemicals is carried out and/or where geogenic sources of toxic substances like hydrothermal waters or volcanic materials are close. This methodology consists in building databases with variables obtained from environmental sampling (water, soil, food and crops), as well as surveys in agricultural communities to identify the occupational and non-occupational exposition to environmental toxics. The method is based on the assessment of environmental, epidemiological and demographic data using GIS and statistical analysis. The purpose is to find correlations between the different types of data taking into account the spatial dimension. This assessment involves the participation of national and international organisms as well as the active participation of agricultural communities and local farming organizations. The first application of this methodology was carried out in Ciudad Romero, a community from Bajo Lempa region (El Salvador, CA) in order to evaluate the drinking water quality. Ciudad Romero is a low income community which population is mainly engaged in agriculture. In this region, massive use of highly toxic pesticides as DDT or Toxaphene was carried out in the past in cotton cultivation and in malaria mitigation. Nowadays a broad fan of agrochemicals is used in the cultivation of corn, sugar cane and vegetables. Drinking water network of this community is not managed by the national water network. It was constructed 7 years ago by the community with financial support of foreign NGOs. This water network is no mapped and, today, it has a poor technical maintenance. Pesticides, heavy metals (Cd, Cr, Pb, Cu, Al, Hg, Zn) and a metalloid (As) were evaluated in 18 sampling points in the homes of Ciudad Romero’s community, in the health center and in the local school. One sample was taken from the drinking water source located outside the agricultural community, and two samples were taken in two different points of pipe network connecting the drinking water source and Ciudad Romero. Residual chlorine concentration and presence of bacteria was detected in the drinking water in community homes, in the local health center and in the local school were sampled. According to our results, chemical pollution exceeding the standards in drinking water source was not detected in the majority of the sampling points. However, a heterogeneous presence of trace of metals and pesticides along the network was found (lower than drinking water standards) and punctual locations where the pollution exceeded the Salvadoran Mandatory Standard for water quality (NSO Spanish acronym) were detected in the community. Two Arsenic values (0.033 and 0.059 mg/L) and a value of Paraquat of 9.74 mg/L exceeded NSO. Presence of residual chlorine was lower than NSO in several points and the sampled points presented large variations. No bacteriological samples higher than the NSO limits were found. This methodology permitted identify some deficiencies in drinking water quality that can be related to pipeline damage in different locations that facilitates the infiltration of pollutants and produces a diminution of residual chlorine. The identified low quality of water could be related to some health problems identified in Ciudad Romero inhabitants. Presence of arsenic pollution could be associated to chronic intoxications that affect different organs like the kidney, and the lack of chlorine could be a risk factor associated with gastrointestinal infections.