Research Product

Acute and chronic bioassays that tested used, whole drilling fluids indicate wide variation in toxicity; drilling fluids from a single well differed in toxicity depending on the well depth and drilling conditions when the fluid was collected. Sublethal effects of used, whole drilling fluids on various life stages of the lobster Homarus americanus suggested alterations in growth rates, respiration rates, biochemical composition, and chemosensory and behavioral responses with sublethal drilling-fluid exposures. The results demonstrated that larval, juvenile, and early post-ecdysial adult crustaceans are particularly sensitive and that much of the toxicity of drilling fluids resides in the water-soluble fraction. Bactericides and diesel oil were shown to be particularly toxic components of drilling fluids. In addition, metal components of drilling fluids were shown to be incorporated into the tissues of exposed crustaceans.