“Origin of As in the freatic aquifer of Bahia Blanca district: A conceptual model for management of arsenotoxicity risk at the SW Pampean region of Argentina”

BLANCO, M. DEL C.; PAOLONI J. D; FIORENTINO C. E; SEQUEIRA M; AMIOTTI N. M; CAFERRI M. I; MORRÁS H; ESPÓSITO M.

Environmental Health Risks

Nova Science Publishers, Inc.

Año: 2009; p. 1 - 5

In Latinamerica health hazards owed to As-drinking waters (As >0.01 µg/l) are increasing, trend observed too at the S-SW pampean region transitional to the patagonian landscape of Argentina, in where the periurban and rural population of Bahía Blanca district (Buenos Aires province) is at risk of chronic endemic hydroarsenicism (HACRE) caused by consumption of As-waters abstracted from the phreatic aquifer. Diseases related to hydroarsenicism are cancer, dermic lessions, vasculopathies and neuropathies, therefore, physicians and health authorities need basic information of As-geoavailability in sediments, movility and incorporation to the aquifer aiming to: 1- understand the transit to humans, 2- provide support to authorithies for As-risk management policies. The aquifer is hosted in an aeolian loess sequence (Pampeano Formation; As 7.5-22 ppm) or alluvial but loess derived sediments (As 7.2-14.5 ppm). At headwaters, groundwater is suitable for human consumption and elevates up to unacceptable levels at the discharge, being usually patchy distributed with a high spatial variability. The pyrite and reductive dissolution hypothesis do not explain the As-contamination extended into the pampean region. As-high levels owe to weathering of loess and loess-derived sediments and to a saline-alkaline hydrochemistry causing As release from silicates and volcanic glass. Moreover, desorption processes in the <2-µm bring As-toxicity. Vulnerability maps are drawn and become available to health authorities being contributive to the national campaign carried by the Argentinian Society of Dermatology to prevent HACRE and its consequences, and, to achieve risk management policies.