Présentations Colloques

Oral Presentation
Session 8.05: Karst aquifers
Padilla Ingrid Y. - Torres Norma I. - Rivera Vilda L.
Monitoring and Assessment of Anthropogenic Contaminant Distributions in Karst System
Well-developed conduit porosity and highly transmissive zones in karst aquifers make these systems highly productive and important freshwater resources, and also impart high vulnerability for contamination. High aquifer productivity and water availability in karst regions promote industrial, agricultural, and population growth that enhance socioeconomic conditions, but also increase the potential for contamination, resource degradation, and exposure. Contamination may come from point or distributed sources, and is distributed according complex hydraulic, fate and transport processes. Assessment of the contaminant distribution is, however, highly dependent on the monitoring scheme used. This work examines the effect of contaminant source type, hydrogeological properties, and monitoring schemes on the spatiotemporal distribution of legacy and emerging contaminants in karst aquifers of eogenetic character. The study is conducted the karst system of northern Puerto Rico. GIS technology and statistical methods are applied to perform spatiotemporal analysis of the collected data. The analysis incorporates data gathered from regulatory agencies and current field measurements of groundwater samples. Results show extensive spatial and temporal contaminations of both legacy and emerging contaminants. Temporal distributions are influenced by contaminant loading functions, which are most of the time unknown, climate, and anthropogenic interventions. Although widely spread, contaminant plumes originating at point sources can be delineated spatially, depending on monitoring schemes. Contaminants entering from distributed sources are much more difficult to delineate, spatially and temporally. Statistical assessment shows that detection and contaminant distributions of contaminants originating from distributed sources are significantly related to hydrogeological properties and land use. Those originating from point sources are influenced by heterogeneous and anisotropic flow patterns induced by natural processes and anthropogenic activities. In both cases, accurate capture of contaminant distribution requires careful implementation of adequate monitoring schemes.
United States