Acute Toxicity of Eight Laboratory-Prepared Generic Drilling Fluids to Mysids (Mysidopsis bahia)

摘要

Acute toxicity tests were conducted during August-September 1983 with eight laboratory-prepared generic drilling fluids (also called muds) and mysids (Mysidopsis bahia) at the U.S. Environmental Protection Agency's Environmental Research Laboratory, Gulf Breeze, Florida. Two of the drilling fluids were tested at the Environmental Research Laboratory, Narragansett, Rhode Island, to confirm the validity of the tests conducted at Gulf Breeze. The test material was the suspended particulate phase (SPP) of each drilling fluid. The SPP was prepared by mixing volumetrically 1 part drilling fluid with 9 parts seawater and allowing the resulting slurry to settle for one hour. The material that remained in suspension was the SPP. Toxicity of the SPP of the drilling fluids ranged from a 96-hour LC50 (the concentration lethal to 50% of the test animals after 96 hours of exposure) of 2.7% for a KCl polymer mud to 65.4% for a lightly treated lignosulfonate mud. No median effect (50% mortality) was observed in three drilling fluids -- a non-dispersed mud, a spud mud, and a seawater-freshwater gel mud.