Establishment of the conceptual model of hydrogeology and fate and transport of chlorinated organic compounds in the fractured aquifer of Jurubatuba region, São Paulo

Abstract

Groundwater from the fractured aquifer in the Jurubatuba region (Sao Paulo city) is contaminated by chlorinated ethene compounds originated from multi-punctual sources of contamination. Public authorities are now searching for ways for the proper management of the situation, which represents a very complex case of contamination, due to the complexity of the hydrogeological medium, the probable occurrence of commingled plumes (which makes difficult the identification of the original source of contamination), and the potential existence of human-health risks to the receptors that consume groundwater.This project, as a compliment of another one financed by FINEP, aims to contribute with the public authorities by providing them with technical basis for the environmental problem management, through the determination of the conceptual models of groundwater movement and of fate and transport of the chlorinated ethenes through the different aquifer levels of the region.The method relates to the procedures developed in the University of Guelph (participant of the project) denominated "Discrete Fracture Network Approach" (DFN method), which involves the application of modern technologies to characterize rock fracture patterns and conduct groundwater monitoring. In this technique, a borehole is accomplished with the continuous recovery of rock cores, which are physically and chemically analyzed. Geophysical logging investigations and hydraulic tests using packers are then accomplished in the borehole, which results will define the design of the FLUTe type of multilevel monitoring system. This system makes possible the hydraulic heads monitoring and the collection of groundwater samples for analyses. The accomplishment of analyses for VOCs, major ions, isotopes (18O, 2H, 87Sr/86Sr, 13C, 37Cl) and bacteria species (through DNA/RNA determination) is predicted in this project. (AU)