THE PROBLEM O F OIL POLLUTION OF THE SEA
287
shallows (Figs. 15 and 16). Such droplets are readily taken into the
food-stream by filter-feeders (see, for example, Spooner, 1968a) and
may be better able to " wet " exposed animal tissues. On the worstaffected sites in Cornwall, solvent-emulsifiers applied liberally, in
conjunction with heavy oil pollution, killed every limpet on the shore,
bringing about the changes in algal cover described above (p. 261 and
in Fig. 17).
Perkins (1968a) offered the opinion that an oil emulsion containing
B P 1002 is more toxic than the emulsifier alone. This is probably true
where the surfactants help the oil to penetrate-the oil then carries in
with it the toxic elements in the emulsifier. Portmann and Connor
(1968) found that the addition of twice its volume of oil to Polyclens
almost doubles its toxicity to cockles Cardium edule and renders it
slightly more toxic to brown shrimps Crangon crangon, although BP
1002 and Gamlen become less toxic when treated in this way. Van de
Wiele (1968) discovered that emulsions of Finasol possess the same
toxicity to the brine-shrimp Artemia salina (L.) and the guppy Lebistes
reticulatus (Peters) whether or not crude oil (which by itself had little
effect in her tests) is added. Preliminary experiments at Swansea using
yeast in a microrespirometer indicate that the addition of an equal
amount of fresh crude oil to B P 1002 approximately halves its toxicity,
which is here exerted at the surface of the test organism. Presumably
the oil binds some of the toxic elements, effectively removing them
from the culture solution.
Since the " Torrey Canyon " disaster, manufacturers have striven
to reduce the toxicity of their emulsifiers, either by diminishing the
proportion of aromatics in the solvent or by eliminating hydrocarbon
solvents altogether. Test blends of B P 1002 in which the solvent
contains a high proportion of aliphatic compounds are considerably less
toxic to gastropod molluscs (Crapp, 1969a) and yeast cultures (unpublished; Fig. 19). Finasol is a similar reformulation of Fina Unisol.
Tests by Capart (1968) show that it is highly toxic at 0.1% and at 100
p.p.m. it is still somewhat toxic to guppies, brine-shrimps, a freshwater snail Planorbis sp. and Daphnia pulex Degeer, but not to
protozoans or other micro-organisms. At 10 p.p.m. it is entirely nontoxic.
The water-soluble dispersants Polycomplex-A and Corexit 7664 have
been compared with various more conventional emulsifiers by Spooner
and Spooner (1968) and Spooner (1968a). Polycomplex-A appears to
be approximately one-fifth as toxic as B P 1002 to a selection of marine
organisms. Corner (quoted by the Spooners) found it twelve times less
toxic in similar tests on barnacle larvae. Corexit, however, is less toxic
287
shallows (Figs. 15 and 16). Such droplets are readily taken into the
food-stream by filter-feeders (see, for example, Spooner, 1968a) and
may be better able to " wet " exposed animal tissues. On the worstaffected sites in Cornwall, solvent-emulsifiers applied liberally, in
conjunction with heavy oil pollution, killed every limpet on the shore,
bringing about the changes in algal cover described above (p. 261 and
in Fig. 17).
Perkins (1968a) offered the opinion that an oil emulsion containing
B P 1002 is more toxic than the emulsifier alone. This is probably true
where the surfactants help the oil to penetrate-the oil then carries in
with it the toxic elements in the emulsifier. Portmann and Connor
(1968) found that the addition of twice its volume of oil to Polyclens
almost doubles its toxicity to cockles Cardium edule and renders it
slightly more toxic to brown shrimps Crangon crangon, although BP
1002 and Gamlen become less toxic when treated in this way. Van de
Wiele (1968) discovered that emulsions of Finasol possess the same
toxicity to the brine-shrimp Artemia salina (L.) and the guppy Lebistes
reticulatus (Peters) whether or not crude oil (which by itself had little
effect in her tests) is added. Preliminary experiments at Swansea using
yeast in a microrespirometer indicate that the addition of an equal
amount of fresh crude oil to B P 1002 approximately halves its toxicity,
which is here exerted at the surface of the test organism. Presumably
the oil binds some of the toxic elements, effectively removing them
from the culture solution.
Since the " Torrey Canyon " disaster, manufacturers have striven
to reduce the toxicity of their emulsifiers, either by diminishing the
proportion of aromatics in the solvent or by eliminating hydrocarbon
solvents altogether. Test blends of B P 1002 in which the solvent
contains a high proportion of aliphatic compounds are considerably less
toxic to gastropod molluscs (Crapp, 1969a) and yeast cultures (unpublished; Fig. 19). Finasol is a similar reformulation of Fina Unisol.
Tests by Capart (1968) show that it is highly toxic at 0.1% and at 100
p.p.m. it is still somewhat toxic to guppies, brine-shrimps, a freshwater snail Planorbis sp. and Daphnia pulex Degeer, but not to
protozoans or other micro-organisms. At 10 p.p.m. it is entirely nontoxic.
The water-soluble dispersants Polycomplex-A and Corexit 7664 have
been compared with various more conventional emulsifiers by Spooner
and Spooner (1968) and Spooner (1968a). Polycomplex-A appears to
be approximately one-fifth as toxic as B P 1002 to a selection of marine
organisms. Corner (quoted by the Spooners) found it twelve times less
toxic in similar tests on barnacle larvae. Corexit, however, is less toxic