USING SYNCHRONOUS SPECTRO-FLUOROMETRY FOR TRACING OIL-CONTAMINATED WATER UNDER AN INACCESSIBLE FACTORY

Organic fluorescent dye tracing is usually not considered when ground water is contaminated with organic compounds because most organic substances fluoresce. We report here the results of two successful dye tracing tests in ground water heavily contaminated by cutting oils beneath a large inaccessible factory. The current remediation strategy includes an engineered drainage system with pumping centers to recover the oil and its derivatives. It was thought that the ground water beneath the factory flowed directly to the drainage system where oil was removed by separation from the ground water. Our dye tracing results, using uranine, sulforhodamine B, and Na-naphtionate, showed that the groundwater flow paths primarily followed the natural hydraulic gradient of a river adjacent to the site, but was also influenced by the induced hydraulic gradient towards the pumping centers. More important to the site remediation, our dye tracing tests further revealed that some contaminated ground water flow paths refract from the general gradients because the natural alluvial conditions were altered by the factory construction and infillings.