THE PROBLEM OF OIL POLLUTION OF THE SEA
281
constitution of the surfactant molecule is important ; the lethal concentration of a nonyl-phenol polyoxyethylene condensate to goldfish
Carassius auratus (L.) after 6 h exposure ranges from 5 p.p.m. to 2 500
p.p.m. according to the ratio of ethylene oxide to nonyl phenol units
(Marchetti, 1964, 1965a). Sublethal effects observed from anionic
surfactants at 0.5-10 p.p.m. include erosion of gill epithelia and
destruction of mucous cells (Schmid and Mann, 1961; Scheier and
Cairns, 1966) or damage to the chemical senses (Bardach et al., 1965).
These result in loss of equilibrium, convulsions and respiratory difficulties (Maldura, 1961) or an inability to detect food (Foster et al., 1966).
Mann and Schmid (1961) found that at 5-10 p.p.m., anionic surfactants
immobilize the sperm of trout Salmo trutta, reduce the fertilization rate
and kill fertile eggs. According to Marchetti (1965b), the fry of rainbow trout S. gairdneri are most resistant to nonyl-phenol polyoxyethylenes when newly hatched (42 p.p.m. is toxic in a 6 h exposure). Their
maximum sensitivity (to 2 p.p.m.) is reached as the yolk-sac is exhausted, but is slightly reduced in older (fingerling) stages to just over
5 p.p.m. The larvae of marine clams Mercenaria mercenaria and oysters
Crassostrea virginica are more sensitive than adults, showing developmental defects at 0.14-3.0 p.p.m. of anionic and 1-0-5.0 p.p.m. of nonionic surfactants (Hidu, 1965). Matulov8 (1964, 1966) has tested a
variety of surfactants on species of the micro-algae Chlamydomonas,
Scenedesmus and Chlorella. A non-ionic compound showed unfavourabie
effects on growth at 5 p.p.m. and was lethal at 200 p.p.m., but had a
slight stimulating effect at concentrations below 2 p.p.m.
Surfactants form only one part of mixtures for dispersing oil spills
and are often the least toxic component (see pp. 284, 287). Chadwick
(1960) tested the toxicity of an American solvent-emulsifier (Tricon)
to striped bass Roccus saxatilis (Walbaum) and found it lethal in 5-10 h
at 10 p.p.m. George (1961) reported the drastic effects of emulsifier
cleansing after a spill in Milford Haven at about the same time as the
Ministry of Agriculture, Fisheries and Food shellfisheries laboratory at
Burnham-on-Crouch was investigating the toxicity of a number of
cleansers to molluscs and crustaceans of commercial importance (Department of Scientific and Industrial Research, 1961 ; Portmann and Connor,
1968 ; Simpson, 1968b). Preliminary tests intended to simulate conditions during the cleansing of a shellfish bed showed that a brief
immersion in 25% suspensions of four emulsifiers caused unacceptable
mortalities (up to 96% in cockles Cardium edule) ; this led to an official
recommendation not to spray oyster layings or cockle beds. The edible
winkle Littorina littorea (L.) appears to be extremely resistant, as was
confirmed by Crapp (1969a) ; the winkle showed a mortality of only
281
constitution of the surfactant molecule is important ; the lethal concentration of a nonyl-phenol polyoxyethylene condensate to goldfish
Carassius auratus (L.) after 6 h exposure ranges from 5 p.p.m. to 2 500
p.p.m. according to the ratio of ethylene oxide to nonyl phenol units
(Marchetti, 1964, 1965a). Sublethal effects observed from anionic
surfactants at 0.5-10 p.p.m. include erosion of gill epithelia and
destruction of mucous cells (Schmid and Mann, 1961; Scheier and
Cairns, 1966) or damage to the chemical senses (Bardach et al., 1965).
These result in loss of equilibrium, convulsions and respiratory difficulties (Maldura, 1961) or an inability to detect food (Foster et al., 1966).
Mann and Schmid (1961) found that at 5-10 p.p.m., anionic surfactants
immobilize the sperm of trout Salmo trutta, reduce the fertilization rate
and kill fertile eggs. According to Marchetti (1965b), the fry of rainbow trout S. gairdneri are most resistant to nonyl-phenol polyoxyethylenes when newly hatched (42 p.p.m. is toxic in a 6 h exposure). Their
maximum sensitivity (to 2 p.p.m.) is reached as the yolk-sac is exhausted, but is slightly reduced in older (fingerling) stages to just over
5 p.p.m. The larvae of marine clams Mercenaria mercenaria and oysters
Crassostrea virginica are more sensitive than adults, showing developmental defects at 0.14-3.0 p.p.m. of anionic and 1-0-5.0 p.p.m. of nonionic surfactants (Hidu, 1965). Matulov8 (1964, 1966) has tested a
variety of surfactants on species of the micro-algae Chlamydomonas,
Scenedesmus and Chlorella. A non-ionic compound showed unfavourabie
effects on growth at 5 p.p.m. and was lethal at 200 p.p.m., but had a
slight stimulating effect at concentrations below 2 p.p.m.
Surfactants form only one part of mixtures for dispersing oil spills
and are often the least toxic component (see pp. 284, 287). Chadwick
(1960) tested the toxicity of an American solvent-emulsifier (Tricon)
to striped bass Roccus saxatilis (Walbaum) and found it lethal in 5-10 h
at 10 p.p.m. George (1961) reported the drastic effects of emulsifier
cleansing after a spill in Milford Haven at about the same time as the
Ministry of Agriculture, Fisheries and Food shellfisheries laboratory at
Burnham-on-Crouch was investigating the toxicity of a number of
cleansers to molluscs and crustaceans of commercial importance (Department of Scientific and Industrial Research, 1961 ; Portmann and Connor,
1968 ; Simpson, 1968b). Preliminary tests intended to simulate conditions during the cleansing of a shellfish bed showed that a brief
immersion in 25% suspensions of four emulsifiers caused unacceptable
mortalities (up to 96% in cockles Cardium edule) ; this led to an official
recommendation not to spray oyster layings or cockle beds. The edible
winkle Littorina littorea (L.) appears to be extremely resistant, as was
confirmed by Crapp (1969a) ; the winkle showed a mortality of only