Pollution transport studies using an in-situ fibre optic photometric sensor

摘要

In order to study the migration of contaminants insoils, we are currently using an in situ fibre optic sensor to trackthe movement of a dye tracer. Details of the sensor is discussedand the results presented of one-dimensional transportexperiments using a water soluble dye and a copper salt. Waterwas forced to percolate downwards in a bed of fine sand, with thehydraulic gradient kept constant during any given experiment. Apulse of contaminant was released on the soil surface, and itsconcentration was subsequently measured using sensors buried attwo depths. This permitted the pollution plume to be tracked. Itwas found that width was independent of hydraulic gradient, aspredicted by the theory of mechanical dispersion for seepageflows with a high Peclet number.