Abstract Reuse water is defined as the reuse of water from treated effluents, it requires careful monitoring to avoid damage to environmental health. This study evaluates the decay of Escherichia coli and Salmonella spp. bacteria in soil irrigated with reused water for agricultural reuse, without damaging public or environmental health. The decay of Escherichia coli and of Salmonella spp. was verified using the Filter Membrane method SS AGAR culture medium was used. The decay curves over time were made using the Sigmaplot program. Each experimental group had 4 pots (one group irrigated with recycled water and the other with drinking water), two pots containing vegetation cover and two containing only soil. In crops irrigated with reused water, the survival time of Salmonella spp. was double compared to the others, and E. coli survival did not vary between groups. Pots with bare soil irrigated with uncontaminated reused water showed a faster decline in Salmonella spp. For agricultural reuse, irrigation must be done by drip and with the use of personal protective equipment. It is essential to create national legislation to protect public and environmental health. effluents health spp used program one , water) others E groups equipment

Resumo A água de reúso é definida como a reutilização de águas provenientes de efluentes tratados, e requer segurança sanitária para evitar danos à saúde ambiental. O objetivo foi avaliar o decaimento de bactérias (Escherichia coli e Salmonella spp.) em solo irrigado com água de reúso, visando o reúso agrícola sem causar danos à saúde pública e ambiental.O decaimento de Escherichia coli foi verificado utilizando o método de Membrana Filtrante, e o de Salmonella spp. foi utilizado o meio de cultura SS AGAR. As curvas de decaimento ao longo do tempo foram feitas pelo programa Sigmaplot. Cada grupo experimental tinha 4 vasos (grupo irrigado com água de reúso e outro com água potável) sendo dois vasos contendo cobertura vegetal e dois contendo apenas solo. Nos cultivos irrigados com água de reúso, o tempo de sobrevivência de Salmonella spp. foi o dobro em comparação aos demais, e a sobrevivência da Escherichia coli não variou entre os grupos. Os vasos com solo nu irrigados com água de reúso sem contaminação mostraram um decaimento da Salmonella spp. mais rápido. Para o reúso agrícola a rega deve ser por gotejamento e com a utilização de equipamentos de proteção individual. É fundamental a criação de legislação nacional, prevenindo danos à saúde pública e ambiental. tratados ambiental spp ambientalO Filtrante AGAR Sigmaplot potável demais grupos rápido individual nacional

RESUMEN Durante el 2018 se evaluaron las concentraciones y distribución de dos indicadores de contaminación fecal en una playa recreacional localizada en el litoral atlántico de Argentina. Utilizando la técnica de membrana filtrante, se determinó la presencia de Escherichia coli y Enterococcus spp. en muestras de arena seca, sedimentos húmedos y agua de mar, mediante monitoreos periódicos considerando la abundancia de lluvia en días previos y valores de temperatura ambiente (máxima y mínima). Las muestras fueron analizadas según fecha de colecta (temporada estival; temporada invernal). Con el propósito de identificar la procedencia de los indicadores seleccionados se empleó la relación: E. coli / enterococos (EC/ENT). Los valores de concentración de ambos indicadores no evidenciaron diferencias significativas entre las temporadas como en los sitios de colecta, a excepción de E. coli, con mayor concentración en el agua durante el periodo estival. Por su parte, la máxima abundancia se identificó en los meses de verano y en los tres sitios muestreados. Por otra parte, el 58 % de las muestras analizadas superaron los límites admisibles. Al analizar la procedencia de la contaminación, se observó una composición de origen mixto (animal y antrópico) en ambas temporadas. Las colonias de EC y ENT persistieron a lo largo del año siendo la arena su mejor reservorio, mientras que los factores ambientales considerados no incidieron en la distribución de dichas bacterias. La prevalencia de sus unidades formadoras de colonias (UFC) por encima de lo recomendable y ocurridas en el periodo de uso intensivo, caracterizarían a este sector de riesgo sanitario durante la temporada evaluada.

ABSTRACT In 2018, the concentrations and distribution of two indicators of fecal contamination were evaluated on a recreational beach located on the Atlantic coast of Argentina. The presence of Escherichia coli and Enterococcus spp. in samples of dry sand, wet sediments, and seawater was determined using the filter membrane technique by periodic monitoring considering the abundance of rain in previous days and ambient temperature values (maximum and minimum). Samples were analyzed according to the date of collection (summer season; winter season). In order to identify the origin of the selected indicators, the ratio E. coli /Enterococci (EC/ENT) was used. The concentration values of both indicators did not show significant differences between seasons and collection sites, with the exception of E. coli, with a higher concentration in the water during the summer period. In turn, the maximum abundance of both was identified in the summer months and in the three sites sampled. On the other hand, 58 % of the samples analyzed exceeded the admissible reference limits. When analyzing the origin of the contamination, a composition of mixed origin (animal and anthropic) was observed in both seasons. The colonies of EC and ENT persisted throughout the year, with sand being their best reservoir, while the environmental factors considered did not affect the distribution of these bacteria. The prevalence of their colony forming units (CFU), above the recommended levels and occurring in the intensive use period, would characterize this sector as a sanitary risk during the evaluated season.