A solid-phase degradation test has been developed to assess the fate in marine sediment of synthetic mud base fluids used in the off-shore drilling industry. The degradation rate of an ester-type drilling fluid was investigated at three nominal concentrations in a fine sand. A naturally occurring triester, olive oil, was used as a positive control and a traditional mineral oil served as an example of a poorly degradable substance. Two synthetic drilling fluids, an ester and a blend of n-alkanes with polyalpha olefin and linear-alpha olefin, were compared in a mud and a coarse sand to examine the effect of different sediments on degradability. Glass jars, containing marine sediment that had been homogeneously mixed with test fluid, were placed in troughs in a continuous flow of seawater. Periodically, triplicate jars were sacrificed and, following solvent extraction, the concentration of test fluid remaining in the sediment was determined by gas chromatography with flame ionization detection. The test was able to reproducibly distinguish between easily degradable and poorly degradable fluids. The rate of degradation was concentration dependent; the half-life increased as the nominal concentration increased. The ester was more rapidly degraded than the blended synthetic drilling fluid and degradation was slower in sand compared with mud.

Abstract-Pigmented Salmon Syndrome is a pollutant-induced hemolytic anemia and hyperbilirubinemia. As part of an investigation of this condition, S2 Atlantic salmon parr (Salmo salar) were exposed to a diesel fuel oil, water soluble fraction (WSF) in combination with a mixture of three resin acids (isopimaric, dehydroabietic, and abietic acids) in a continuous-flow freshwater system. The total nominal concentrations of resin acids in the exposure tanks were 10, 50, and 100 g/L; the diesel WSF was generated in situ and provided a mean hydrocarbon concentration of 2.0 Ϯ 0.1 mg/L (n ϭ 12) during the 9-d exposure period. Exposure to the diesel WSF alone depressed liver bilirubin UDP-glucuronosyl transferase (UDPGT) activity and induced phenol UDPGT activity. Exposure to the diesel WSF in the absence or presence of resin acids induced liver cytochrome P4501A and increased the concentrations in the plasma of the enzymes lactate dehydrogenase, alkaline phosphatase, and glutamic oxaloacetic transaminase. The combined exposure to diesel WSF with either 50 or 100 g/L total resin acid caused significant elevations in the concentrations of bilirubin in the plasma and many of these fish had yellow pigmentation on the ventral surface and around the gill arches. The results demonstrate that exposure to combinations of two groups of contaminants can result in the manifestation of toxic effects not apparent from exposure to either of these chemicals in isolation.

No abstract

Pigmented Salmon Syndrome is a pollutant‐induced hemolytic anemia and hyperbilirubinemia. As part of an investigation of this condition, S2 Atlantic salmon parr (Salmo salar) were exposed to a diesel fuel oil, water soluble fraction (WSF) in combination with a mixture of three resin acids (isopimaric, dehydroabietic, and abietic acids) in a continuous‐flow freshwater system. The total nominal concentrations of resin acids in the exposure tanks were 10, 50, and 100 μg/L; the diesel WSF was generated in situ and provided a mean hydrocarbon concentration of 2.0 ±0.1 mg/L (n = 12) during the 9‐d exposure period. Exposure to the diesel WSF alone depressed liver bilirubin UDP‐glucuronosyl transferase (UDPGT) activity and induced phenol UDPGT activity. Exposure to the diesel WSF in the absence or presence of resin acids induced liver cytochrome P4501A and increased the concentrations in the plasma of the enzymes lactate dehydrogenase, alkaline phosphatase, and glutamic oxaloacetic transaminase. The combined exposure to diesel WSF with either 50 or 100 μg/L total resin acid caused significant elevations in the concentrations of bilirubin in the plasma and many of these fish had yellow pigmentation on the ventral surface and around the gill arches. The results demonstrate that exposure to combinations of two groups of contaminants can result in the manifestation of toxic effects not apparent from exposure to either of these chemicals in isolation.