Use of GPR to map prestige fuel layers below sand on the beaches of galicia

In November, 2002, the Prestige fuel oil tanker was damaged during a storm 45 km off the coast of Galicia (Spain). More than 30.000 tons of oil were leaked and arrived on the Galician coast. Some months later, layers of fuel contamination still appear at different depths in the sand of the beaches, from some cm to 1-2 meters. The use of GPR to detect and map fuel layers below sand is difficult due to the presence of salt water from the sea. Even so, GPR could be used in some inland areas, which are under the influence of high winter tides but remain out of their influence during spring and summer time. Some in-situ tests were carried out on the beaches with 500 & 800 MHz antennas. Because of the good results obtained, a cart with wide wheels was adapted to survey the beaches. In this study an example of one of the 800 MHz antenna tests made is shown, together with a study case made with the wide-wheels cart where it w:as possible to detect a fuel layer at a depth of 40-50 cm.