The toxicity of four oils to Palaemonetes pugio (Holthuis) in relation to uptake and retention of specific petroleum hydrocarbons.

The effects of water-soluble fractions (WSFs) of Southern Louisiana, Kuwait, no. 2 Fuel and Bunker C oils on Palaemonetes were tested. Bioassays were performed to determine the toxicities of the oils and provide information for sublethal experiments. The 48 hour TLm values at 21C showed that the two crude oils were less toxic than refined or residual oil. In uptake and depuration experiments it was found that hydrocarbons were concentrated in the tissues of grass shrimp exposed to WSFs. However, when Palaemonetes survival initial exposure, depuration occurred. Animals exposed to 2.61 ppm WSF of No. 2 Fuel for six hours contained 2.07 ppm dimethylnaphthalene. After 24 hours exposure in the same solution the tissues contained only .32 ppm DMN. After 435 hours in clean, filtered sea water, grass shrimp contained 0.196 DMN. Therefore the more toxic oils contained higher proportions of naphthalene, methylnaphathalene and dimethylnaphthalene which are rapidly accumulated by Palaemonetes yet are readily released if the initial exposure is not lethal.