Acute toxicity of drilling fluids used in Mexican offshore facilities tested with postlarvae white shrimp (Litopenaeus setiferus)

Static acute toxicity tests were carried out with seven generic drilling fluids and six drilling muds used in offshore drilling facilities in the Sonda of Campeche area and with sodium dodecyl sulfate as reference toxicant compound to evaluate the potential of postlarvae white shrimp (Litopenaeus setiferus) as test specie for toxicological analysis of drilling fluids. Toxicity of seven generic drilling fluids tested simultaneously between Mysidopsis bahia and Litopenaeus setiferus indicated a similar response for both species according with the limit of 30,000 ppm in the suspended particle phase analysis due to only the EPA-83-001 fluid was toxic while the others did not. Non-acute toxic effects with Litopenaeus setiferus were in water-based drilling muds collected in field, while the oil-based muds were highly toxic although there was no toxicity criteria that could be applied to this type of muds. Replication and sensitivity tests with Litopenaeus setiferus using sodium dodecyl sulfate, showed a low variability and for instance, a constant response that highly suggest this organism, in postlarvae stage, as a reference specie for testing drilling systems and also, water quality indicator in the Sonda of Campeche, Mexico. Moreover, sensitivity of this organism was also similar to Mysidopsis bahia, reference specie used by EPA. This is an abstract of a paper presented at the SPE International Conference on Health, Safety and Environment in Oil and gas Exploration and Production (Stavanger, Norway, 6/26-28/2000).