TRAVEL TIME PREDICTION OF CONTAMINANT TRANSPORT IN SANDY SOIL

A great number of human activities, such as agriculture, ranching, mining and oil extraction, are responsible for the human development, cause negative environmental impacts. This study focuses on travel time determination expending by some product coming from petroleum industry: car's oil, which can affect the ground when a spill occurs. Plexiglass columns, with four experimental sampling ports located each 15 cm, and a multipoint pumping were used in this experiment. The sandy soil was saturated with a saline tracer to control the variables that could affect the contaminant transport due to air presence where gaseous phase of could move into them. Once saturated conditions were confirmed, the oil was injected in an upward flow, at sample intervals of five minutes during four hours. The findings provide an approximation of dispersivity equivalent to 1,27m(2)/day, when soils had a gradation between the sieve No. 4 and No. 50; the travel time in this case was 8.8 days. Likewise, for a medium with gradation between sieve No. 50 and No. 200, the dispersivity value was 0.741m(2)/day and the travel time was 8.9 days. These results allow inferring that in the way as the grain size decreases, so does the ability to move fluid in the environment and therefore the greater travel time. The procedure established in this experimental work can be used for other types of compounds, although the technique must be improved before be used in the field. It is also recommended further study to confirm the approximations made.