Advances and challenges to implementing the project: arsenic in Uruguayan groundwater and associated health risk

Abstract

In Uruguay there is a great concern about the arsenic (As) geogenic contamination in groundwater as an environmental health problem, after rather high levels of As in groundwater in some areas (above 20 μg L-1) were reported and considering that the majority of the rural population consumes drinking water from private aquifer wells. On the other hand, Uruguay has an abundance of wells and quality groundwater, and it is vital to protect Uruguayan aquifers as important resources. In this respect we proposed and started to implement a multidisciplinary and interinstitutional program: AsURU Project (“Arsenic in Uruguayan groundwater and associated health risk”) (website: facebook.com/AsURUArsenico) to address this environmental and health problem. Although there are no systematic studies on the quality of groundwater or on the incidence of health effects associated with As exposure, a medical geology study is being performed by the research team led by Nelly Mañay, Ph.D., to assess health risks retrospectively by correlating reported cancer incidence with As groundwater levels, distributed by different localities. The AsURU Project has developed a working plan that consists of: (a) identification of main Uruguayan aquifers with relevant As data, (b) subdivision in study areas, (c) establishment of geographically delimited pilot areas following specific criteria: i) areas which have drinking water supplied by aquifers with As levels above WHO guidelines; ii) should represent a significative extension of the concerned aquifer; iii) have enough information about the aquifer hydraulic parameters and iv) availability of quantitative data about population´s exposure timeline to groundwater and shreds of evidence about health adverse effects (d) hydrogeologic, hydrodynamic and hydrogeochemical study to identify the origin of As and space-time mobility, (e) evaluation of As exposure through groundwater in the pilot areas, (e) recommend solutions like good construction and other remedial actions. The AsURU Project has seen great progress and also encountered challenges. Its main achievements in line with the proposed action plan have been: (1) the identification of pilot areas with As concentration levels in groundwater above 20 μg L-1 (max. permitted level as per Uruguayan regulations); and even with As level concentrations above 10 μg L-1 (max. permitted level as per WHO regulations). (2) the formation of three work groups to develop three related projects: the Groundwater Resource Group, the Chemistry and Medical Geology Group, and the North Littoral Group; (3) meetings were held, including the “I Symposium of Arsenic in Uruguayan Groundwater” in 2018, with the participation of various state-owned companies and the “II Symposium of Arsenic in Uruguayan Groundwater” in 2022. However, there is still no specific financial support for developing the program in its totality.