The composition of drilled materials and the use of drilling fluids are the main factors taken into consideration. By atomic absorption spectrometry (AAS), traces of cadmium, lead, mercury and chromium have been detected. The treatment of drilling fluids has been done in two different manners. The first one supposed the improvement of the circulation/rinsing process of drilling fluids, meanwhile the second focused on more environmental friendly drilling fluids. Both methods are argumented and discussed.
