The Madeleine-Blanchette spring, on the coast, Baillif (Guadeloupe, 2013).
© BRGM - Laure Ducreux
Guadeloupe has many springs, some of which are channelled to supply drinking water to the population and are therefore subject to European regulations. On the other hand, many unchannelled springs are not subject to any health inspections even though they are used by the population for consumption or domestic purposes. The strong traditional use of certain springs and the recurrent cuts in the drinking water network explain the use of this water, the quality of which is poorly known.
In this context, the ARS asked BRGM to carry out a spring water characterisation study to determine the health risks associated with its use in order to raise public awareness of these risks and implement a strategy to protect the health of the population.
An inventory throughout the territory identified 85 active springs, 20 of which were prioritised for investigation, depending in particular on their use. Based on samples taken during periods of low and high water, the analytical spectrum tested allowed the identification of:
- to the south-east of Basse-Terre, an impact linked to agricultural pollution (historical use of organochlorine pesticides including chlordecone);
- to the north of Basse-Terre, the occasional and notable presence of metals (iron, aluminium manganese) attributed to the geochemical background or to industrial activity;
- at La Désirade and along the shoreline, excessive values for chloride and sodium related to salt-water intrusion;
- for almost all sources, bacteriological contamination due to sewage water.
Source Matouba Eaux Vives (Saint-Claude, Guadeloupe, 2013).
© BRGM Laure Ducreux
Using the results
For each source characterised, an identity sheet has been generated, detailing its location, the pressures recorded or the results obtained, and especially the contamination highlighted (exceeding of limits and water quality criteria according to the decree of 11 January 2007 as amended). The purpose of these sheets is to inform water stakeholders and the general public about the quality of the springs analysed. In order to ensure that they are distributed widely, they have also been stored in the subsurface database (BSS).
- Regional Health Agency of Guadeloupe, Saint-Martin, Saint-Barthélemy
The study provided us with immediately usable results that allowed us to determine the level of pollution of alternative water sources that are unfit for consumption. From now on, the municipalities must use this data to inform the population of the health risk involved. Together with BRGM, we launched another study in early 2020 that will complete our in-depth knowledge of roadside springs in Guadeloupe.