APPLICATION OF ENVIRONMENTAL TRACERS TO THE STUDY OF NUTRIENT CONTAMINATION IN JAMAICA’S WATER RESOURCES

Water resources across the world have been suffering severe stress due to many factors including poor management, pollution and changes in rainfall patterns due to climate variability. The small islands of the Caribbean, such as Jamaica, are particularly affected as their freshwater systems have been impacted by prolonged periods of drought, extreme weather events, seawater intrusion and increased urbanization, which have resulted in water shortages and degrading water quality. The protection and sustainable management of Jamaica’s natural water resources require an understanding of the dynamics of their physical behavior and chemical constituents. Isotopic tracers have proven to be very effective tools for studying the transport and mixing of surface and subsurface water on regional and global scales, but they have had limited application in small island developing states.

In this talk, the application of stable and radioactive isotopes (δ²H-H₂O, δ¹⁸O-H₂O, δ³H-H₂O, δ¹⁵N-NO₃, δ¹⁸O-NO₃) in the investigation of the surface and groundwaters in three important watersheds in Jamaica (Kingston, Rio Cobre and Milk River) is discussed. Land use in these watersheds is highly diversified, including residential communities (rural and urban), agriculture, mining and industrial areas. In addition to decreasing freshwater availability due to prolonged droughts and increasing urbanization, the surface and groundwaters in these basins are prone to contamination due to these human activities. Thus, the results of conventional hydrochemical analyses for major ions are incorporated, to examine the contamination sources to these freshwater systems. These investigations have shown that the freshwaters are recharged by multiple sources, and various pollution sources were identified, including sewage, fertilizer run-off and wastewater from agricultural activities, as well as seawater intrusion. The analytical techniques used, sources, pathways and fate of contaminants, and the implications of these findings to the sustainable management of these water resources will be discussed.