Page 101 - Environmental Control in Petroleum Engineering

88 Environmental Control in Petroleum Engineering

mysid shrimp data cannot be directly compared to data that were
obtained using a protocol that does not require the same dilution.
The presence of mineral oil-based mud and synthetic oil-based mud
(polyalphaolefin) on cuttings at concentrations up to 8.4% had no
significant effect on the growth of mud minnows (Fundulus grandis),
The uptake of mineral oils, however, was higher than that of synthetic
oils, suggesting that synthetic, high-molecular weight liquids may have
a lower toxicity (Rushing et al., 1991; Jones et al., 1991).
For a particular organism, the life-cycle stage at which exposure
occurs can impact how toxic a material is. Table 3-5 shows the results
of bioassays on four organisms as a function of life-cycle stage for
exposure to No. 2 fuel oil. From this table, it can be seen that some
species have a higher tolerance at younger stages, while other species
have a higher tolerance at older stages (National Research Council,
1985), In most species, however, the adults are more tolerant of

Table 3-5
Effect of Life-Cycle Stage on Fuel Oil Toxicity

96-hour LC 50
Species (ppm)
Brown Shrimp:
Postlarvae 6.6
Small juveniles 3.8
Large juveniles 2.9
White Shrimp:
Postlarvae 1.3
Juveniles 1.0
Grass Shrimp:
Larvae 1.2
Postlarvae 2.3
Adults 3.6
Polychaeta:
4 segments 8.3
18 segments 5.8
32 segments 5.5
Adults (40 segments) 4.0
Source: after National Research Council, 1985.
Copyright © 1985, National Academy of Sciences.
Courtesy of National Academy Press, Washington, D.C.