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A toxicological evaluation of a plastic Oil absorbant
Marine Pollution Bulletin
example, on the size of the brood from which they came (Harris, 1964). In many cases this asymptotic weight is at, or below, some 770 g. At best then, one would expect the experimental groups of Miller et al. (1978) to show lower percentage increases in body weight than their control group. At worst, the birds in their experimental groups may have stopped growing before they were fed oil. On the data they present, we are not convinced that their oil treatments did cause a cessation of growth. The doses of crude oil used in our study are, both in terms of size and of duration, in excess of the quantities a wild bird might be expected to consume. We consider it unlikely, therefore, that wild birds ingesting Forties Field crude oil would suffer serious, direct toxic effects. Of much more serious consequence would be the
external fouling that a bird consuming oil would inevitably suffer. The catastrophic effects of such fouling on the plumage and the ability to thermo-regulate are well known. We would like to thank British Petroleum for their gift of crude oil. Our manuscript was read by Dr. W. R. P. Bourne, Prof. G. M. Dunnet, Dr. 1. Priede and Prof. F. G. T. Holliday; we are grateful to them for their comments. Crane, R. K. & Mandelstam, P. (1960). The active transport of sugars by various preparations of Hamster intestine. Biochem. biophys. Acta, 4 5 , 4 6 0 - 4 7 6 . Harris, M. P. (1964). Aspects of the breeding biology of the gulls Larus argentatus, L. fuscus and L. marinus. Ibid., 106,432-456. Kadlec, J. A., Drury, W. H. & Onion, D. K. (1969). Growth and mortality of herring gull chicks. Bird Banding, 40, 222-233. Miller, D. S., Peakall, D. B. & Kinter, W. B. (1978). Ingestion of crude oil: sublethal effects in herring gull chicks. Science, 199, 315-317.
)4arine Pollution Bulletin, Vol. 9, pp. 276-278 Pergamon Press Ltd. 1978. Printed in Great Britain
A Toxicological Evaluation of a Plastic Oil Absorbant SUNNIVA L O N N I N G and B E R N D T E. H A G S T R O M *
Institute of Biology and Geology, University of TromsO, N-9001 TromsO, Norway *Present address: KABI Research Department, S-105 25 Stockholm 30, Sweden.
The effect of a plastic oil absorbantt was tested on several different test organisms of different taxonomic positions. The results indicate that the Oil Killer under the experimental conditions described, acts as an almost inert nontoxic substance. The Oil Killer dissolves in the presence of methylene chloride but in spite of this no negative effects were recorded. In combination with crude oil the Oil Killer seems rather to reduce the serious ill effects exerted by oil alone.
The problems connected with the increasing oil spill at sea have, as yet, not got a satisfactory solution. The oil dispersants now in c o m m o n use have been found to be considerably more toxic than oil and in combination with oil, substances of highly toxic properties are set free to act on the living organisms in the sea (e.g. Latiff, 1969; Sprague & Carson, 1970; L0nning & HagstrOm, 1975, 1976). The usual mechanical methods for containing and recovering oil are difficult to manage under severe weather conditions and are only adequate on a limited basis. The present study deals with a new product, the so-called 'Oil Killer' which is a plastic oil absorbant produced by Kvaerner Brug A / S , Oslo, Norway. The Oil Killer has properties which give promise of usefulness in fighting even extensive oil spills.
~r'Oil Killer' from Kvaerner Brug A/S, Oslo, N,orway.
276
Material and Methods
The experiments have been carried out at Stazione Zoologica in Naples, using gametes and embryos of the regular sea urchin Paracentrotus lividus (Lamarck) as material. At the Marine Biological Station at TromsO experiments were made with the sea urchin Strongylocentrotus pallidus (G.O. Sars) and larvae from the flatfishes Platichthys flesus (Linnaeus) and Pleuronectes platessa (Linnaeus). Also planktonic organisms, particularly copepods, were used for testing. The experiments in Naples were carried out with extracts of plastic oil absorbant (Oil Killer) and extracts of mixtures of absorbant and crude Ekofisk oil. Extraction of 100 mg absorbant was made in 100 ml of pure seawater or in 100 ml of seawater containing 0.15 M methylene chloride. 100 mg of absorbant was likewise mixed with 1 ml of Ekofisk oil in 99 ml of seawater. The extractions were made on a magnetic stirrer at about 500 rpm for 90 min. The temperature was kept at 20°C. Only the water phase was used in the experiments. The effect of the various extracts including the control extracts (i.e. seawater extracts of Ekofisk oil and methylene chloride respectively) was investigated according to the techniques described previously (Hagstrt~m & L0nning, 1973; L0nning & HagstrOm, 1975). Pretreatment of the spermatozoa was made in order to study possible mutagenic effects on the sperm nucleus. The influence on the interaction of the gametes at fertilization was made according to the fertilization
Volume 9 / N u m b e r 10/October 1978 TABLE 1
Fertilization rate experimentwith eggs and sperm from Paracentrotus lividus. The sperm were pretreated for 2 min before insemination in 1 part of extract (extr.) and 3 parts of seawater.
TABLE 2 Fertilization rate experiment with eggs and sperm from Paracentrotus lividus. Extract was added at the moment of insemination to a final concentration of 1: 10.
% Fertilized eggs
% Fertilized eggs
Seconds after insemination
15
20
25
30
co
57
87
97
99
100
100
67
91
97
99
99
100
5
54
82
97
99
100
100
Oil Killer + Ekofisk oil, extr. 1:I0
5
32
81
96
98
99
100
Methylene chloride, extr. 1: 10
9
47
81
92
94
97
98
100
Ekofisk oil, extr. 1:10
19
61
86
98
97
98
1130
100
5
10
15
20
25
30
co
Control
17
71
94
98
100
100
100
Oil Killer, extr. 1:10
Oil Killer, extr. 1:4
21
63
90
98
99
100
100
Oil Killer + methylene chloride, extr. 1:4
17
57
87
97
99
100
100
Oil Killer + methylene chloride, extr. I:10
Oil Killer + Ekofisk oil, extr. 1: 4
16
63
89
98
99
100
100
Methylene chloride, extr. 1:4
8
46
89
97
99
100
Ekofisk oil, extr. 1:4
16
63
92
97
99
100
rate method, which gives an extremely sensitive estimation of possible toxic effects (cf. HagstrOm & HagstrOm, 1959). In the experiments carried out in TromsO the test media contained 10 or 20 mg oil absorbant per 100 ml seawater or the same amounts with 0.1 ml Ekofisk crude oil. Further details about the experimental technique are given in connection with the descriptions of the results. It is to be observed that the TromsO experiments were made at about 6°C whereas those of Naples were carried out at 20°C. Both temperatures coincide with the conditions prevailing in the sea and are of interest since differences in temperature may be encountered in the practical use of the Oil Killer.
Results Experiments in Naples with Oil Killer extracts The experiments with various extracts of Oil Killer gave uniform results and it appeared that the plastic absorbant exhibits almost none, or at least insignificant toxic effects on fertilization and development. Pretreatment of the sperm did not interfere appreciably with the very sensitive determinations of the fertilization rate (Table 1). The extract of the absorbant in seawater did not lower the fertilization rate appreciably. The following cleavage and differentiation of the inseminated eggs was entirely normal. The extract of methylene chloride (which is a true solution) showed a somewhat decreased fertilization rate, which also probably has some bearing on the result of the extract of Oil Killer with seawater and methylene chloride (Table 1). The extracts had only marginal effects on fertilization; the Ekofisk oil extract, however, inflicted disturbances on the further differentiation of the larvae and there were disturbances of the skeleton in larvae generated by sperm pretreated in extracts of Ekofisk oil. O f particular interest is to note that the extract of Oil Killer + Ekofisk oil in seawater interfered only slightly with fertilization and the ensuing development of the embryos. Consequently, the addition of absorbant corrected the ill effects of oil. The relation above refers to experiments with pretreatment of the sperm for 2 min in the extracts. Conse-
Control
5
10
7 14
quently no extract or active substance was present at the m o m e n t of fertilization or during the ensuing cleavage and differentiation of the embryos. In other experiments the various extracts were present at the m o m e n t of insemination and were permitted to act on the embryos throughout the development up to the self-maintaining pluteus stage. Also in this type of experiment no direct toxic effects of the oil absorbant were registered (Table 2). However, the combined extracts of Oil Killer and Ekofisk oil showed a minor retardation in the fertilization rate. This is surprising since neither Ekofisk oil nor Oil Killer influences the fertilization rate negatively (Table 2). The development in extracts of Oil Killer, Oil Killer + methylene chloride and methylene chloride resulted in normal plutei as in the control. In extract of oil a b s o r b a n t + E k o f i s k oil 20°70 of the larvae became a b n o r m a l with the injuries to the skeleton characteristic of crude oil (LOnning & HagstrOm, 1975). The extract of Ekofisk oil alone, however, gave considerably worse effects on the development. This indicates that Oil Killer reduces the ill effects of oil extracts. Experiments in TromsO with Oil Killerpresent in the test medium In the series of experiments carried out in TromsO using sea urchin material no negative results attributable to the Oil Killer were recorded. The eggs were fertilized to 100°70 in the presence of Oil Killer or Oil Killer+ Ekofisk oil, and also the further development in the test medium was normal. Larvae of flatfishes were transferred to seawater containing Oil Killer, Oil Killer + Ekofisk oil, or Ekofisk oil. In most experiments the transfer was made after hatching. Neither the viability nor the behaviour of the fish larvae seemed to be influenced by the presence of oil absorbant. Oil Killer + Ekofisk oil had similar effects as Ekofisk oil resulting in a lower viability (LOnning, 1977). It is possible that in these experiments the amount of oil absorbant, 10 or 20 mg, was not sufficient to neutralize the oil, since an oil film was still present on the surface. Studies of the effects of oil absorbant on other planktonic organisms were carried out using the natural population of zooplankton collected from the surface waters. This plankton mainly consisted of various 277
Marine Pollution Bulletin
species of copepods. No effects of Oil Killer were registered on these organisms. As already mentioned the experiments in TromsO were different in design from those performed in Naples. Moreover, the external conditions, and particularly the temperature, differed considerably from those found in the Mediterranean. The time factor is also quite different in Troms0 and Naples. In Troms0 the experiments often lasted for a week whereas the Naples experiments were completed within 48 h. Nevertheless, the results with Oil Killer were uniform on the two widely separated localities and no grave toxic effects were ever recorded.
HagstrOm, B. E. & LOnning, S. (1973). The sea urchin egg as a testing object in toxicology. Acta Pharmac. ToxicoL, 32, Suppl. 1, 1-49. Latiff, S. A. (1969). Preliminary results of the experiments on the toxicity of oil counteracting agent (Esso Corexit 7664), with and without Iraq crude oil, for selected members of marine plankton. Arch. Fisch Wiss., 20, 182-185. LOnning, S. (1977). The effects of crude Ekofisk oil and oil products on marine fish larvae. Astarte, 10, 3 7 - 4 7 . LOnning, S. & HagstrOm, B. E. (1975). The effects of crude oils and the dispersant Corexit 866,7, on sea urchin gametes and embryos. Norw. J. ZooL, 23, 121-129. L0nning, S. & HagstrOm, B. E. (1976). Deleterious effects of Corexit 9527 on fertilization and development. 3,far. Pollut. BulL, 7, 124-127. Sprague, J. B, & Carson, W. G. (1970). Toxicity tests with oil dispersants in connection with oil spill at Chedabucto Bay, Nova Scotia. Fish. Res. Bd Can. Techn. Rep. no. 201.
HagstrOm, B. E, & HagstrOm, B. (1959). The effect of decreased and increased temperatures'on fertilization. Exp. CellRes., 16, 174-183.
Marine Pollution Bulletin, Vol. 9, pp. 278-280 Pergamon Press t.td. 1978. Printed in Great Britain
Acute Toxicity of Copper to a Copepod M. MORAITOU-APOSTOLOPOULOU Zoological Laboratory, University of A thens, Greece The acute toxicity of copper to the marine copepod Acartia clausi was determined by means of static bioassays. Natural copepod assemblages from two different locations, one from an area polluted with industrial effluents and domestic wastes and another from a relatively uncontaminated area, were compared. Results of metal toxicity tests expressed as 48 h LCs0 values indicate a significant difference in the tolerance of copper between the two populations, with the LCso of the pollution-adapted population higher than that of the population from the uncontaminated area.
The effects of heavy metals on aquatic organisms is currently attracting widespread attention, particularly in studies related to industrial pollution. The establishment of critical concentrations of metal ion pollutants in aquatic systems by bioassay techniques is necessary in determining 'acceptable' levels of pollution. The use of copper in antifouling paint, in the treatment of diseases of fishes and as an algicide, increases the interest in the effects of this metal on aquatic organisms. The most extensive research on the effects of copper has been directed mostly to fishes because of their economic value. There are still only few data for the marine zooplankton, although their small size, and hence sensitivity, suggest their choice as bioassay organisms. The burden of marine pollution is first and most intensively felt in coastal waters, adjacent to the major sources of pollution activities, so animals from these regions are particularly suitable for such studies. In this paper the effect of copper on the survival of the marine copepod Acartia clausi, collected from two differently polluted areas of the Saronic Gulf, has been studied. 278
The Saronic Gulf (Gulf of Athens) is part of the south Aegean Sea (Fig. I). Due to the economic, industrial and social importance of the surrounding coast, the Gulf has become an area of particular interest in Greece. The northern part (Elefsis Bay-Keratsini) is subject to a high degree of pollution because of the industrial wastes and hydrocarbon products discarded from a flourishing industry around the bay and the large quantities of organic matter discharged at Keratsini from the main sewage outfall of the cities of Athens and Piraeus. Previous planktological studies conducted at Keratsini indicate that this point experiences primary organic pollution (Moraitou-Apostolopoulou, in press), and high concentrations of trace elements in Elefsis Bay sediments have been recently reported (Grimanis et al., 1976). Research on the content of sediments of Saronic Gulf (Pavlou & Dexter, 1973) and also planktological studies (Moraitou-Apostolopoulou, 1974, 1976; Kiortsis & Moraitou-Apostolopoulou, 1975; MoraitouApostolopoulou & Kiortsis, 1976) have shown that although the northern part of the Gulf is heavily polluted, southwards the influence of pollution sources is reduced and the south Saronic Gulf can be considered as a relatively clear area. Material and Methods
Acartia clausi is a calanoid copepod common in the Mediterranean. Frequent but not abundant in the Aegean Sea (Moraitou-Apostolopoulou, 1972), it increases in numbers in the Saronic Gulf, representing 50°70 of the total numbers of copepods (MoraitouApostolopoulou, 1974). This species also presents a very clear regional distribution. Inside Elefsis Bay it forms
example, on the size of the brood from which they came (Harris, 1964). In many cases this asymptotic weight is at, or below, some 770 g. At best then, one would expect the experimental groups of Miller et al. (1978) to show lower percentage increases in body weight than their control group. At worst, the birds in their experimental groups may have stopped growing before they were fed oil. On the data they present, we are not convinced that their oil treatments did cause a cessation of growth. The doses of crude oil used in our study are, both in terms of size and of duration, in excess of the quantities a wild bird might be expected to consume. We consider it unlikely, therefore, that wild birds ingesting Forties Field crude oil would suffer serious, direct toxic effects. Of much more serious consequence would be the
external fouling that a bird consuming oil would inevitably suffer. The catastrophic effects of such fouling on the plumage and the ability to thermo-regulate are well known. We would like to thank British Petroleum for their gift of crude oil. Our manuscript was read by Dr. W. R. P. Bourne, Prof. G. M. Dunnet, Dr. 1. Priede and Prof. F. G. T. Holliday; we are grateful to them for their comments. Crane, R. K. & Mandelstam, P. (1960). The active transport of sugars by various preparations of Hamster intestine. Biochem. biophys. Acta, 4 5 , 4 6 0 - 4 7 6 . Harris, M. P. (1964). Aspects of the breeding biology of the gulls Larus argentatus, L. fuscus and L. marinus. Ibid., 106,432-456. Kadlec, J. A., Drury, W. H. & Onion, D. K. (1969). Growth and mortality of herring gull chicks. Bird Banding, 40, 222-233. Miller, D. S., Peakall, D. B. & Kinter, W. B. (1978). Ingestion of crude oil: sublethal effects in herring gull chicks. Science, 199, 315-317.
)4arine Pollution Bulletin, Vol. 9, pp. 276-278 Pergamon Press Ltd. 1978. Printed in Great Britain
A Toxicological Evaluation of a Plastic Oil Absorbant SUNNIVA L O N N I N G and B E R N D T E. H A G S T R O M *
Institute of Biology and Geology, University of TromsO, N-9001 TromsO, Norway *Present address: KABI Research Department, S-105 25 Stockholm 30, Sweden.
The effect of a plastic oil absorbantt was tested on several different test organisms of different taxonomic positions. The results indicate that the Oil Killer under the experimental conditions described, acts as an almost inert nontoxic substance. The Oil Killer dissolves in the presence of methylene chloride but in spite of this no negative effects were recorded. In combination with crude oil the Oil Killer seems rather to reduce the serious ill effects exerted by oil alone.
The problems connected with the increasing oil spill at sea have, as yet, not got a satisfactory solution. The oil dispersants now in c o m m o n use have been found to be considerably more toxic than oil and in combination with oil, substances of highly toxic properties are set free to act on the living organisms in the sea (e.g. Latiff, 1969; Sprague & Carson, 1970; L0nning & HagstrOm, 1975, 1976). The usual mechanical methods for containing and recovering oil are difficult to manage under severe weather conditions and are only adequate on a limited basis. The present study deals with a new product, the so-called 'Oil Killer' which is a plastic oil absorbant produced by Kvaerner Brug A / S , Oslo, Norway. The Oil Killer has properties which give promise of usefulness in fighting even extensive oil spills.
~r'Oil Killer' from Kvaerner Brug A/S, Oslo, N,orway.
276
Material and Methods
The experiments have been carried out at Stazione Zoologica in Naples, using gametes and embryos of the regular sea urchin Paracentrotus lividus (Lamarck) as material. At the Marine Biological Station at TromsO experiments were made with the sea urchin Strongylocentrotus pallidus (G.O. Sars) and larvae from the flatfishes Platichthys flesus (Linnaeus) and Pleuronectes platessa (Linnaeus). Also planktonic organisms, particularly copepods, were used for testing. The experiments in Naples were carried out with extracts of plastic oil absorbant (Oil Killer) and extracts of mixtures of absorbant and crude Ekofisk oil. Extraction of 100 mg absorbant was made in 100 ml of pure seawater or in 100 ml of seawater containing 0.15 M methylene chloride. 100 mg of absorbant was likewise mixed with 1 ml of Ekofisk oil in 99 ml of seawater. The extractions were made on a magnetic stirrer at about 500 rpm for 90 min. The temperature was kept at 20°C. Only the water phase was used in the experiments. The effect of the various extracts including the control extracts (i.e. seawater extracts of Ekofisk oil and methylene chloride respectively) was investigated according to the techniques described previously (Hagstrt~m & L0nning, 1973; L0nning & HagstrOm, 1975). Pretreatment of the spermatozoa was made in order to study possible mutagenic effects on the sperm nucleus. The influence on the interaction of the gametes at fertilization was made according to the fertilization
Volume 9 / N u m b e r 10/October 1978 TABLE 1
Fertilization rate experimentwith eggs and sperm from Paracentrotus lividus. The sperm were pretreated for 2 min before insemination in 1 part of extract (extr.) and 3 parts of seawater.
TABLE 2 Fertilization rate experiment with eggs and sperm from Paracentrotus lividus. Extract was added at the moment of insemination to a final concentration of 1: 10.
% Fertilized eggs
% Fertilized eggs
Seconds after insemination
15
20
25
30
co
57
87
97
99
100
100
67
91
97
99
99
100
5
54
82
97
99
100
100
Oil Killer + Ekofisk oil, extr. 1:I0
5
32
81
96
98
99
100
Methylene chloride, extr. 1: 10
9
47
81
92
94
97
98
100
Ekofisk oil, extr. 1:10
19
61
86
98
97
98
1130
100
5
10
15
20
25
30
co
Control
17
71
94
98
100
100
100
Oil Killer, extr. 1:10
Oil Killer, extr. 1:4
21
63
90
98
99
100
100
Oil Killer + methylene chloride, extr. 1:4
17
57
87
97
99
100
100
Oil Killer + methylene chloride, extr. I:10
Oil Killer + Ekofisk oil, extr. 1: 4
16
63
89
98
99
100
100
Methylene chloride, extr. 1:4
8
46
89
97
99
100
Ekofisk oil, extr. 1:4
16
63
92
97
99
100
rate method, which gives an extremely sensitive estimation of possible toxic effects (cf. HagstrOm & HagstrOm, 1959). In the experiments carried out in TromsO the test media contained 10 or 20 mg oil absorbant per 100 ml seawater or the same amounts with 0.1 ml Ekofisk crude oil. Further details about the experimental technique are given in connection with the descriptions of the results. It is to be observed that the TromsO experiments were made at about 6°C whereas those of Naples were carried out at 20°C. Both temperatures coincide with the conditions prevailing in the sea and are of interest since differences in temperature may be encountered in the practical use of the Oil Killer.
Results Experiments in Naples with Oil Killer extracts The experiments with various extracts of Oil Killer gave uniform results and it appeared that the plastic absorbant exhibits almost none, or at least insignificant toxic effects on fertilization and development. Pretreatment of the sperm did not interfere appreciably with the very sensitive determinations of the fertilization rate (Table 1). The extract of the absorbant in seawater did not lower the fertilization rate appreciably. The following cleavage and differentiation of the inseminated eggs was entirely normal. The extract of methylene chloride (which is a true solution) showed a somewhat decreased fertilization rate, which also probably has some bearing on the result of the extract of Oil Killer with seawater and methylene chloride (Table 1). The extracts had only marginal effects on fertilization; the Ekofisk oil extract, however, inflicted disturbances on the further differentiation of the larvae and there were disturbances of the skeleton in larvae generated by sperm pretreated in extracts of Ekofisk oil. O f particular interest is to note that the extract of Oil Killer + Ekofisk oil in seawater interfered only slightly with fertilization and the ensuing development of the embryos. Consequently, the addition of absorbant corrected the ill effects of oil. The relation above refers to experiments with pretreatment of the sperm for 2 min in the extracts. Conse-
Control
5
10
7 14
quently no extract or active substance was present at the m o m e n t of fertilization or during the ensuing cleavage and differentiation of the embryos. In other experiments the various extracts were present at the m o m e n t of insemination and were permitted to act on the embryos throughout the development up to the self-maintaining pluteus stage. Also in this type of experiment no direct toxic effects of the oil absorbant were registered (Table 2). However, the combined extracts of Oil Killer and Ekofisk oil showed a minor retardation in the fertilization rate. This is surprising since neither Ekofisk oil nor Oil Killer influences the fertilization rate negatively (Table 2). The development in extracts of Oil Killer, Oil Killer + methylene chloride and methylene chloride resulted in normal plutei as in the control. In extract of oil a b s o r b a n t + E k o f i s k oil 20°70 of the larvae became a b n o r m a l with the injuries to the skeleton characteristic of crude oil (LOnning & HagstrOm, 1975). The extract of Ekofisk oil alone, however, gave considerably worse effects on the development. This indicates that Oil Killer reduces the ill effects of oil extracts. Experiments in TromsO with Oil Killerpresent in the test medium In the series of experiments carried out in TromsO using sea urchin material no negative results attributable to the Oil Killer were recorded. The eggs were fertilized to 100°70 in the presence of Oil Killer or Oil Killer+ Ekofisk oil, and also the further development in the test medium was normal. Larvae of flatfishes were transferred to seawater containing Oil Killer, Oil Killer + Ekofisk oil, or Ekofisk oil. In most experiments the transfer was made after hatching. Neither the viability nor the behaviour of the fish larvae seemed to be influenced by the presence of oil absorbant. Oil Killer + Ekofisk oil had similar effects as Ekofisk oil resulting in a lower viability (LOnning, 1977). It is possible that in these experiments the amount of oil absorbant, 10 or 20 mg, was not sufficient to neutralize the oil, since an oil film was still present on the surface. Studies of the effects of oil absorbant on other planktonic organisms were carried out using the natural population of zooplankton collected from the surface waters. This plankton mainly consisted of various 277
Marine Pollution Bulletin
species of copepods. No effects of Oil Killer were registered on these organisms. As already mentioned the experiments in TromsO were different in design from those performed in Naples. Moreover, the external conditions, and particularly the temperature, differed considerably from those found in the Mediterranean. The time factor is also quite different in Troms0 and Naples. In Troms0 the experiments often lasted for a week whereas the Naples experiments were completed within 48 h. Nevertheless, the results with Oil Killer were uniform on the two widely separated localities and no grave toxic effects were ever recorded.
HagstrOm, B. E. & LOnning, S. (1973). The sea urchin egg as a testing object in toxicology. Acta Pharmac. ToxicoL, 32, Suppl. 1, 1-49. Latiff, S. A. (1969). Preliminary results of the experiments on the toxicity of oil counteracting agent (Esso Corexit 7664), with and without Iraq crude oil, for selected members of marine plankton. Arch. Fisch Wiss., 20, 182-185. LOnning, S. (1977). The effects of crude Ekofisk oil and oil products on marine fish larvae. Astarte, 10, 3 7 - 4 7 . LOnning, S. & HagstrOm, B. E. (1975). The effects of crude oils and the dispersant Corexit 866,7, on sea urchin gametes and embryos. Norw. J. ZooL, 23, 121-129. L0nning, S. & HagstrOm, B. E. (1976). Deleterious effects of Corexit 9527 on fertilization and development. 3,far. Pollut. BulL, 7, 124-127. Sprague, J. B, & Carson, W. G. (1970). Toxicity tests with oil dispersants in connection with oil spill at Chedabucto Bay, Nova Scotia. Fish. Res. Bd Can. Techn. Rep. no. 201.
HagstrOm, B. E, & HagstrOm, B. (1959). The effect of decreased and increased temperatures'on fertilization. Exp. CellRes., 16, 174-183.
Marine Pollution Bulletin, Vol. 9, pp. 278-280 Pergamon Press t.td. 1978. Printed in Great Britain
Acute Toxicity of Copper to a Copepod M. MORAITOU-APOSTOLOPOULOU Zoological Laboratory, University of A thens, Greece The acute toxicity of copper to the marine copepod Acartia clausi was determined by means of static bioassays. Natural copepod assemblages from two different locations, one from an area polluted with industrial effluents and domestic wastes and another from a relatively uncontaminated area, were compared. Results of metal toxicity tests expressed as 48 h LCs0 values indicate a significant difference in the tolerance of copper between the two populations, with the LCso of the pollution-adapted population higher than that of the population from the uncontaminated area.
The effects of heavy metals on aquatic organisms is currently attracting widespread attention, particularly in studies related to industrial pollution. The establishment of critical concentrations of metal ion pollutants in aquatic systems by bioassay techniques is necessary in determining 'acceptable' levels of pollution. The use of copper in antifouling paint, in the treatment of diseases of fishes and as an algicide, increases the interest in the effects of this metal on aquatic organisms. The most extensive research on the effects of copper has been directed mostly to fishes because of their economic value. There are still only few data for the marine zooplankton, although their small size, and hence sensitivity, suggest their choice as bioassay organisms. The burden of marine pollution is first and most intensively felt in coastal waters, adjacent to the major sources of pollution activities, so animals from these regions are particularly suitable for such studies. In this paper the effect of copper on the survival of the marine copepod Acartia clausi, collected from two differently polluted areas of the Saronic Gulf, has been studied. 278
The Saronic Gulf (Gulf of Athens) is part of the south Aegean Sea (Fig. I). Due to the economic, industrial and social importance of the surrounding coast, the Gulf has become an area of particular interest in Greece. The northern part (Elefsis Bay-Keratsini) is subject to a high degree of pollution because of the industrial wastes and hydrocarbon products discarded from a flourishing industry around the bay and the large quantities of organic matter discharged at Keratsini from the main sewage outfall of the cities of Athens and Piraeus. Previous planktological studies conducted at Keratsini indicate that this point experiences primary organic pollution (Moraitou-Apostolopoulou, in press), and high concentrations of trace elements in Elefsis Bay sediments have been recently reported (Grimanis et al., 1976). Research on the content of sediments of Saronic Gulf (Pavlou & Dexter, 1973) and also planktological studies (Moraitou-Apostolopoulou, 1974, 1976; Kiortsis & Moraitou-Apostolopoulou, 1975; MoraitouApostolopoulou & Kiortsis, 1976) have shown that although the northern part of the Gulf is heavily polluted, southwards the influence of pollution sources is reduced and the south Saronic Gulf can be considered as a relatively clear area. Material and Methods
Acartia clausi is a calanoid copepod common in the Mediterranean. Frequent but not abundant in the Aegean Sea (Moraitou-Apostolopoulou, 1972), it increases in numbers in the Saronic Gulf, representing 50°70 of the total numbers of copepods (MoraitouApostolopoulou, 1974). This species also presents a very clear regional distribution. Inside Elefsis Bay it forms