Pressures and impacts on the quality of Groundwater in accordance to the WFD implementation: the Guadeloupe case study
Résumé
This study deals with the analysis of pressures and impacts on the groundwater (GW) resources of Guadeloupe (French Caribbean Island). It was carried out in 2013 in accordance with the provisions of Article 5 of the Water Framework Directive (WFD). To complete the WFD objectives, a practical methodology was developed to link the inlet pressures of the aquifer systems with the impacts on the quality of the groundwater resource.
Regarding the water quality issues, raw data, extracted from the French national database (www.ades.fr) that gathers field data, notably of the French WFD surveillance network, were used. Specific substances that i) exceed the threshold values (TV), ii) are closed to a TV (e.g. > TV/2 as a safety factor), iii) are considered to be relevant compounds were targeted.
Meanwhile, two pressures and impacts matrix were created on the basis of a literature review for industrial compounds and agricultural ones respectively. The 2 matrix give theoretical pressures from industrial activities or agricultural practices that could contribute to the presence of a targeted substance or a combination of targeted substances in GW.
The theoretical pressures were compared with the industrial sites location and the major cultures inventoried in the agricultural plots. Former industrial site were also used to take into account the potentially long time transfer of substances to GW.
The results of this approach at the scale of the Guadeloupe groundwater bodies reveal that most of the pollution is related to agricultural practices, notably the use of banned pesticides for some GW bodies. It was also concluded that the impact of pesticides can be explained by the culture of bananas and sugar cane that imply the use of a large amount of Persistent Organic Pollutants (POPs), such as kepone on banana plantations, for several years.