Page 100 - Environmental Control in Petroleum Engineering

The Impact of Drilling and Production Operations 8?

Table 3-4b
Summary of Bioassay Tests on Marine Organisms

Test
Duration LC 50
Hydrocarbon Test Species (hr) (ppm)

Dimethylnaaphthalene Palaemonetes 96 0,5
Cancer 96 0,5
Neanthes 96 2
Penaus aztecus 24 0.5
Copepod 24 0,5
Cyprinodon 24 5
Trimethylnaphthalene Neanthes 96 2
Cancer 24 0.25
Fluorene Palaemonetes 96 0.25
Neanthes 96 1
Cyprinodon 96 1.5
Dibenzothiophene Palaemonetes 96 0,25
Cyprinodon 96 3
Phenanthrene Palaemonetes 24 0.25
Neanthes 96 0.5
Methylphenanthrene Neanthes 96 0.25
Fluoranthene Neanthes 96 0.5
Source: after National Research Council, J985.
Copyright © 1985, National Academy of Sciences.
Courtesy of National Academy Press, Washington, D.C

hydrocarbons than the single ring aromatics of benzene, toluene,
ethylbenzene, and xylene (BTEX).
The high toxicity of aromatic hydrocarbons relative to other hydro-
carbons can be seen by comparing the 96-hour mysid shrimp toxicity
for drilling muds using diesel oil to that using mineral oils. Diesel oil
contains as much as 60% aromatic components, while some mineral
oils contain less than 1%. LC 50 values for diesel are around 2,000 pprn,
while those for some mineral oils are greater than 1,000,000 ppm, in
which case less than 50% of the test species died during the test period
(Derkics and Souders, 1993). As discussed below in the section on
drilling fluids, the mysid shrimp test protocol dilutes the oil with sea
water by a factor of nine before the test is conducted. Thus, these