Resumen

IRIARTE R, María M  y  GOMEZ V, Ana. Domestic water potability in Nueva Esparta state, Venezuela. INHRR [online]. 2008, vol.39, n.2, pp.23-34. ISSN 0798-0477.

This work evaluates the compliance with drinking water norms in 757 samples collected in Margarita and Coche Islands, Venezuela. Samples were analyzed between 1999 and 2006 and the results are registered in the Microbiology Laboratory Certification Books (Fundación La Salle de Ciencias Naturales). Analysis of total coliforms, fecal coliforms, E. coli, faecal streptococci and P. aeruginosa (MPN/100 ml) and heterotrophic plate counts (FCU/ml) were made according to COVENIN and APHA norms. The pH, temperature and free chlorine levels were measured. In the water coming directly from the continent the percentage of data not conforming with norms was lower (free chlorine level 64%; total coliforms 27% and heterotrophic plate count 17%) when compared to the average from the internal distribution net (free chlorine level 84%; total coliforms 60% and heterotrophic plate count 40%). A negative significative relation between free chlorine levels and total coliforms, fecal coliforms, P. aeruginosa and heterotrophic plate count (r = -0.27; -0.19; -0.41 and -0.38 respectively; p < 0.0001), showing chlorine´s importance to maintain microbial safety of drinking water. Equally, a positive significative relation (p < 0.0001) was found between the numbers of evaluated groups, pointing a common source of bacteria. It was concluded that a high percentage of the evaluated samples of water did not fulfill the drinking water norms and it involved potential risks to public health.

Palabras clave : Drinking water; Water´s analysis; Water´s standard; Water supply.