Regional-scale leaching assessments for Tenerife: Effect of data uncertainties

This paper reports assessments of nonpoint-source (NPS) ground water vulnerability due to pesticide leaching for the Canary Island of Tenerife. Index-based estimates of contamination potential were made for the pesticides Carbofuran and Ethoprophos using the attenuation and retardation factors (AF and RF). The major objective of this effort was to characterize the data-related uncertainties, using first-order uncertainty analysis; that are associated with the new pesticide Leaching estimates for Tenerife. The crop, recharge, and soils data for Tenerife were overlaid in this regional-scale study using a geographic information system approach. The strategy was to identify the effect of supplemental information in reducing uncertainties in the island-wide vulnerability estimates. Data improvements were estimated as reductions in the AF and RF input parameter uncertainties. The greatest improvements in the Tenerife vulnerability estimates were found for reductions in the chemical data uncertainties. The new vulnerability assessments for Tenerife will be useful for future agrochemical regulation decisions and for targeting critical areas that may require remediation.