During a general malacological survey for freshwater gastropods in northern Patagonia, a population of Biomphalaria was encountered at Agua Escondida. Biomphalaria spp. are freshwater pulmonates of biomedical importance, uncommon in Mendoza Province, and often act as intermediate hosts for Schistosoma mansoni. By looking at both morphological and molecular characters, we describe a detailed process of identification and characterization of Biomphalaria peregrina from a location towards the extremity of its species range. A reference DNA ‘barcode’ is presented. As B. peregrina has been shown to be a permissive experimental host of S. mansoni, snails were also screened in the field for schistosomiasis and later in the laboratory using a novel polymerase chain reaction-based assay but no infections were found. Considering the transmission potential of this species, increased vigilance for intestinal schistosomiasis is recommended, especially if local environmental conditions become favourable for disease transmission, for example, through future climate change and intensification of irrigation.

La presencia en el agua de virus entericos supone un riesgo para la salud, y los criterios bacteriologicos establecidos como indices de contaminacion fecal no protegen frente a infecciones de origen virico. Los metodos empleados para la deteccion de virus en aguas son costosos, laboriosos y lentos por lo que no es posible su uso rutinario. Para solventar estos problemas, se han propuesto a determinados bacteriofagos como organismos indicadores de la presencia de virus, aunque cada uno de ellos presenta diferentes ventajas e inconvenientes, no existiendo en la actualidad un organismo indicador universalmente aceptado para el control de virus en aguas. La aparicion de la reaccion en cadena de la polimerasa (PCR), y su aplicacion como metodo alternativo para la deteccion de microorganismos, ha revolucionado el diagnostico en microbiologia, ya que permite obtener excelentes resultados de sensibilidad y especificidad de un modo rapido. La aplicacion de esta tecnica al control de virus en aguas, resuelve totalmente los problemas derivados de los metodos tradicionales. Aunque quedan todavia muchos aspectos por desarrollar, la aparicion de innovaciones metodologicas en el campo de la PCR, el abaratamiento de su coste y el desarrollo de metodos de preparacion de las muestras que eliminen la presencia de inhibidores de la reaccion, permitiran en un futuro no muy lejano, emplearla rutinariamente en el control virologico del agua.

Dissolved organic carbon (DOC) is composed of a diverse array of compounds, predominantly humic substances, and is a near ubiquitous component of natural groundwater, notwithstanding climatic extremes such as arid and hyper-arid settings. Despite being a frequently measured parameter of groundwater quality, the complexity of DOC composition and reaction behaviour means that links between concentration and human health risk are difficult to quantify and few examples are reported in the literature. Measured concentrations from natural/unpolluted groundwater are typically below 4 mg C/l, whilst concentrations above these levels generally indicate anthropogenic influences and/or contamination issues and can potentially compromise water safety. Treatment processes are effective at reducing DOC concentrations, but refractory humic substance reaction with chlorine during the disinfection process produces suspected carcinogenic disinfectant by-products (DBPs). However, despite engineered artificial recharge systems being commonly used to remove DOC from recycled treated wastewaters, little research has been conducted on the presence of DBPs in potable groundwater systems. In recent years, the capacity to measure the influence of organic matter on colloidal contaminants and its influence on the mobility of pathogenic microorganisms has aided understanding of transport processes in aquifers. Additionally, advances in polymerase chain reaction techniques used for the detection, identification, and quantification of waterborne pathogens, provide a method to confidently investigate the behaviour of DOC and its effect on contaminant transfer in aquifers. This paper provides a summary of DOC occurrence in groundwater bodies and associated issues capable of indirectly affecting human health.