Potential Exposure of Emerging Contaminants in Tap water from Karst Groundwater Sources

Abstract

Karst aquifers are the most productive groundwater supplies on Earth, providing 20–25% of the global population water needs. In Puerto Rico, groundwater provides a significant source of drinking water (52%). The northern karst system of Puerto Rico is very susceptible to contamination, serving as route of exposure to human and wildlife in the region. Previous studies of groundwater in that region have shown significant distribution of different contaminants beyond demarked sources of contamination, some of them related to long-lasting health problems. This work develops a spatio-temporal distribution of phthalate contamination in groundwater and tap water in the northern karst region of Puerto Rico and determines the statistical correlation between different factors and phthalate contamination. Geographic Information System (GIS) technologies and statistical models are applied to attain these objectives. Results show that there is an extensive contamination with phthalates in tap water and groundwater samples. Phthalates were detected in 53% of the tap water samples and 6.84% of the groundwater samples. They were detected as mixture components in areas of high urban and industrial development. Results from the statistical models show that the presence of phthalates in groundwater is significantly related to hydraulic conductivity of the aquifers and time. The analysis suggests that land use could be an additional source of contamination to tap water. The extensive spatio-temporal contamination of groundwater suggests that contaminants can persist in the environment for long periods of time and that hydrogeological factors are important factors contributing to the presence of phthalates in karst systems.