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Oil dispersant toxicity
TABLE 4
Browning, E. (1961). Toxicity of Industrial Metals, Butterworths, London, England. location 4, western coast of Canada. Chapman, A. C. & Linden, H. (1926). On the presence of compounds of arsenic in marine crustaceans and shell fish. Minimum Median Maximum Analyst, 51: 563-564. No. of pg/g /~g/g /~g/g Dick, J & Pugsley, L. I. (1950). The arsenic, lead, tin, copper samples (wet (wet (wet and iron contents of canned clams, oysters, crabs, lobsters analysed weight) weight) weight) and shrimps. Can. J. Res., 28: 199-201. Marine invertebrates Ellis, M. M. (1934). Arsenic storage in game fish. Copeia, 2: 97. Fernandez del Riego, A. (1968). Determination of arsenic in Crab 9 2.4 6.6 14.0 marine fish. Bol. Inst. Espan. Oceanogr., 134. (Cancer magister) Fukai, R. & Meinke, W. W. (1959). Some activation analyses Clam 4 .~1.0 ~t.0 2.8 of six trace elements in marine biological ash. Nature, 1114: (Macoma sp.; 815-816. Clinocardium sp.) Johnels, A. G., Westtermark, T., Berg, W., Persson, P. I. & Marine fish Sjostrand, B. (1967). Pike (Esox lucius L) and some acquatic Rockfish 3 ~0.4 ~0.4 1.7 organisms in Sweden as indicators of mercury contamina(Sebastes sp.) tion in the environment. Oikos, 18: 323-333. Greenling 1 ~0.4 lrukayama, K. (1967). The pollution of Minamata Bay and (Hexagrammos sp.) Minamata disease. Adv. Water Pol. Res., 3: 153. Kurland, L. T., Faro, S. N. & Siedler, H. (1960). Minamata disease. The outbreak of a neurologic order in Minamata levels, such as fish, may be from the methylation of Japan, and its relationship to the ingestion of seafood arsenic by anaerobic bacteria present in marine sedicontaminated by mercuric compounds. World Neurol., 1: ments. McBride and Wolfe (1971) published data on the 370-395. LeBlanc, P. I. & Jackson, A. L. (1973). Dry ashing technique biosynthesis of dimethylarsine by cell extracts and for the determination of arsenic in marine fish. J. AOAC whole cells of 'Methanobacterium' strain M o l l , under (in press). McBride, B. C. & Wolfe, R. S. (1971). Biosynthesis of dimeanaerobic conditions, thylarsine by methanobacterinm. Biochem. 10: (23): The level of arsenic in shellfish, crustaceans, fresh4312-4317. water and marine fish used for food purposes should be Rucker, R. R. & Amend, D. F. (1969). Absorption and retention of organic mercurials by rainbow trout and chinook further investigated to document its distribution, and and sockeye salmon. Progressive Fish-Cult., 31: 197-201. since arsenic is highly toxic (As+ + +) it is important that Stratton, ,G. & Whitehead, H. C. (1962). Colorimetric deterits pathway through the aquatic environment and the ruination of arsenic in water with silver diethyldithiocarbamate. J. AWWA, 861-864. chemical form(s) concentrated by fish also be investi- Uthe, J. F. & Bligh, E. G. (1971). Preliminary survey of heavy gated, metal contamination of Canadian freshwater fish. J. Fish. Res. Bd. Can. 28: 5. P. J. LEBLANC Vasak, V. & Sedivec, V. (1952). Kolorimetrick~ stanoveni A. L. JACKSON arsenu. Chem. Listy, 46: 341-344. T,W. Beak Consultants Limited, Wobeser, G. N., Nielson, O., Dunlop, R. H. & Atton, F. M. (1970). Mercury concentrations in tissues of fish from the Toronto, Ontario, Canada. Saskatchewan river. I. Fish. Res. Bd. Can., 27: 830-834. Concentrations of arsenic in marine fish and invertebrates from
Oil Dispersant Toxicity Toxiefly tests nmktg a wide variety el shore animals reveal flint Iha ~teat gSmeralton of ~ have vetT l o w toxicity and no lonlPtetm eBeets, During the past five years, this laboratory has been concerned with the accurate assessment of toxic effects on marine animals, particularly invertebrates. The methods devised, although not regarded as other than an interim stage in the improvement of technique, have been described by Perkins (1972a, b). Both of these papers were concerned with the essentials of methodelegy; however, these methods have been developed during work upon a range of toxic substances which include oil dispersant formulations, and results obtained with oil dispersants are reported below, The test animals we have used have been selected on the basis of direct and indirect economic importance to inshore fisheries. The hermit crab Eupagurus bernhardus, a carnivorous species known to be highly sensitive to toxic materials, is an important fish food species upon which the basic screening of toxic materials is based in this laboratory. The oyster Ostrea, shrimp Crangon and plaice Pleuronectes platessa are important elements of estuarine and inshore fisheries, while sand flats are important nursery grounds for the latter. The shore crab Carcinus and the starfish Asterias are imp o n a n t predators of inshore fisheries and the former 9o
may contribute to the food of some fish, e.g. skate. The winkles Littorina spp. are among the most abundant of the littoral animals and, although resistant to toxic materials, are useful test animals because they m a y be marked and released to the shore after treatment; here their subsequent history--i.e, mortality and g r o w t h - may be studied. The edible periwinkles Littorina littorea are the subject of a fishery in some areas. The gunnel Pholis gunneUus is a fish which inhabits stony shores, seeks shelter beneath stones when the tide recedes and may therefore be affected directly by the consequences of an oil spill. The substances tested included a toxic standard (TS) of a formulation comparable with the highly toxic materials used at the time of the Torrey Canyon disaster, and two of the less toxic formulation developed since that time, viz. BP l l 0 0 X and Shell Dispersant LT, more briefly referred to as BPX and S D L T respectively below.
Methods The methods used were basically the determination of the 48 h LC~, at 20°C with a 5-day recovery period. Animals were always acclimated to laboratory conditions for at least a week before the beginning of laboratory tests. Departures from the standard 20°C were
made in those tests where large volumes o r m o r e space was required for the test animals. Subsequent to this determination, the animals used in the actual LC,0 test or in fresh and larger aliquots were maintained for prolonged periods in which a n y development of delayed mortality and any effect on growth was looked for. The fish Pleuronectes and Pholis were kept in the laboratory; L. littorea was released to the shore; Ostrea was transferred to live boxes at L o c h Sween. The Eupagurus from the highest dose in which 100% survived the 5-day recovery period were maintained individually in the laboratory, and the development of delayed mortality was examined. T h e methods employed are described by Perkins (1968, 1970, 1972a); the precautions necessary to the collection of test animals are described by Perkins (1972b).
Determiaatioas
T h e results of tests performed in this laboratory upon the earlier generation of oil-emulsifiers and the toxic standard are given in Table 1. It will be seen that the susceptibility of the individual species differs, but that the toxicity with respect to the sensitive Eupagurus bernhardus was of the order of 10 ppm. Delayed mortality effects occur in polychaete larvae (Wilson, 1968) and gastropod molluscs, viz. winkles and dogwhelks (Perkins, 1970), which had been treated with these materials, T h e results of the 48 h LC.~0 tests performed upon a n u m b e r of test animals with S D L T and B P X are given in Table 2. There are differences in the response of the individual species to the dispersants. Nevertheless, it will be noted that the toxicity of these formulations is significantly less than that of the earlier types. F o r example, the 48 h LCso of the toxic standard with respect to the sensitive Eupagurus bernh~dus was 11 p p m at 16°C, whereas that for S D L T and B P X exceeded 10,000 p p m at 20°C.
TABLE 2 The median tolerance limits of some marine animals with respect to Shell Dispersant LT (SDLT) and BPX. species
Temp. °C
Eupagurus bernhardus (hermit crab) Ostrea edulis (oyster) Crangon crangon (shrimp) Carcinus maenas (shore crab) Asterias rubens (starfish) Pleuronectes platessa (plaice) Solea solea (sole)
48 SDLT
h LC~0
BPX
20
~10,000
~10,000
20
~ 10,000
2,500
18
ca. 1,000
~l,000a
16.5-18.5
20,000
20,000
20
~6,000
16
~ 10,000
(i) 3,000 (ii)6,000 7,100
12.5-13.5
~10,0oo
-
aCrangon mortality in 1,000 ppm SDLT and BPX----55 and 10o% respectively. This result should be treated with caution since there were problems involved in the transport of this animal to the laboratory. N.B. The fish were not treated at 20°C because of the handling problems involved.
Long-termGrowth and Mortality Aliquots of L. littorea exposed for 24 h to doses of S D L T and B P X m u c h greater than 5,000 p p m were released to the shore (Table 3). In four weeks, neither group evinced a 50% mortality at the 5,000 p p m treatment and both formulations were rather less toxic to this species in the long term than BP1002. Nevertheless, at the 5,000 p p m dose B P X was markedly more toxic than SDLT. Recaptures in both these experiments were very g o o d and little mortality apparently developed at treatments below 5,000 p p m of either dispersant. The long-term effects, i.e. up to 28-29 days after treatment, of B P 1002 upon Littorina saxatilis are given in Table 4. In contrast, L. saxatilis exposed for 24 h to 5,000 p p m of S D L T suffered no mortality in the 5-day recovery period. I n large aliquots treated for 24 h at
TABLE 1 The median tolerance fimits of some marine invertebrates with respect to formulations typical of those used in the Torrey Canyon di~ster. Species
Formulation
Crangon crangon (shrimp) Eupagurus bernhardus (hermit crab)
BP 1002
Careinus maenas (shore crab) Littorina littorea (edible winkle) L. saxatilis (rough winkle) Thais (Nueella) lapillus (dog whelk) Mytilus edulis (mussel) Ostrea edulis (Oyster)
BP 1002 Dispersant TS Slickgone Petrofina TS BP 1002 BP 1002 Dispersant TS Slickgone BP 1002
6 h LCs0 16.0 -
-
-
8.0a 6.5a 60.0a 40.0a 80.0a ~3,000b (750 to ~3,000) 3,200b (400 to >3,200) 1,000b (150, 250, 1,000) 90, 320a
-
>640a
-
35-100 -
BP 1002
-
BP 1002
-
BP 1002 Slickgone Petrofina Dispersant TS
24 h LC~0
~800 ~5,120
~640a -
48 h LCs~ 96 h LC~0 5.8c
-
I 1.0 15c -
5.0a 29.0a -
-
-
-
-
-
2.5a -
aPerkins, 1968; bPerkins, 1968, 1970; cSimpson, 1968. Bracketed or multiple LCs0 result from paradoxical curves. 91
TABLE 3 The longer-term effects of a 24 h exposure of Littorina littorea to oil emulsifier formulations. All animals released to the shore subsequent to treatment, BP 1002a Dose (ppm) Control 7.5 30 190 750 3,000 21 Days recovery % Recaptured 40 42 41 29 32 38 % Cumulative mortality 0 0 0 3.0 l l.0 6.0 28 Days recovery % Recaptured 34 38 34 25 26 25 % Cumulative mortality 0 0 1.0 5.0 12.0 6.5 SDLT Dose (ppm) Control 50 500 5,000 23 Days recovery % Recaptured 44 91 73 93 % Cumulative mortality 0 0 1.0 0 27 Days recovery % Recaptured 55 98 88 96 % Cumulative mortality 0 1 1 0 BPX 23 Days recovery %
Dose (ppm) Control 50 500 5,000 44 0 55 0
Recaptured
% Cumulative mortality 27 Days recovery % Recaptured % Cumulative mortality aPerkins, 1970.
94 1 98 2
70 2 76 2
64 19 67 21
concentrations of SDLT up to 10,000 ppm, no noticeable mortality developed during one month after release to the shore. No significant differences in the growth and fecundity were noted between controls and animals treated to 10,000 ppm. TABLE 4 Long-term effeffcts of a 24 h exposure of Littorina saxatilis to BP 1002. All animals released to the shore subsequent to treatment (Perkins, 1970). Expt. $68 / 9 22 Days recovery % Recaptured % Cumulative mortality 29 Days recovery % Recaptured % Cumulative mortality Expt. $68/! 7 22 % % 28 % %
Control
Dose (ppm) 300 750 1,500 3,000
51 0
58 3
51 6
45 6
35 22
37 0
39 3
36 6
27 6
34 22
Dose (ppm)
Control 0.1 1.0 5.0 10 30 10o 300 Days recovery Recaptured 34 44 60 57 62 47 49 40 Cumulative mortality 0 0 3 2 2 3 2 11 Days recovery Recaptured 38 56 59 58 65 56 60 47 Cumulative mortafity 0 1 11 4 6 6 3 12
In general, those E u p a g u r u s subjected to all types of oil emulsifier formulation, old and new, did not show delayed mortality. Studies with the oyster Ostrea were affected by predation of the controls and treated animals alike. At the end of a 5-day recovery period there was no significant difference in mortality between the controls and the treated animals. In two experiments the mean mortality was about 5% (5% in controls; 3-8% in treated animals). On removal to Loch Sween, a high mortality developed in both groups--range 47% to 98%; controls 73% to 86%--during the following 1¼ years. Many of these 'dead' animals had completely disappeared (up to 69% per aliquot). Predation by the starfish ,4sterias was known to have occurred, and crabs 92
or a similar predator, are implicated where the total loss of shell occurred. These results have little value except that in 17, 33 and 64 weeks the predators apparently found treated animals to be neither more nor less palatable than the controls. In those animals which survived, and certainly at 17 weeks in experiment SC70/85, there was no evidence of retarded growth in the treated animals when compared with the controls. In connection with these experiments it should be noted that during 1969-70 the hatchery which was the source of test animals was troubled with high levels of zinc in their seawater source. A high hatchery death of oysters resulted and although an excessive mortality was not evident during acclimation and test here, these stocks gave trouble over the whole period 1969-71. The plaice used in these experiments were captured at Arisaig and transported to the laboratory by road. After treatment, they were maintained in the laboratory for 11 weeks during which period they were fed on mussel flesh (Table 5). During this period, mortality occurred in all groups, including the controls. At the end of the experiment, there was some evidence of the paradoxical effects which characterize detergents (Schatz et al., 1964), but at concentrations up to at least 1,000 ppm, survival of plaice treated with both SDLT and BPX was little different from that of the controls. At the highest concentration, viz. 10,000 ppm BPX was markedly more toxic than SDLT. TABLE 5 Long-term recovery of plaice, Pleuronectes platessa, exposed to 48 h treatments with SDLT and BPX (n. per aliquot= 16). % Survival Dose
SDLT BPX (48 h LC~=I0,000 ppm)(48 h LC~o=7,100 ppm) 1 week 11 weeks 1 week 11 weeks recovery recovery recovery recovery
Control 100 1,000 5,000 10,000
100 100 95 88 100
69 56 75 19 44
100 I00 100 95 0
69 50 75 38 0
Toxicity of Oil/Oil Dispersant M i x t u r e s A limited series of experiments were performed using 25% oil emulsifier/75% Kuwait crude oil mixtures. The results of these experiments are recorded in Table 6. It will be noted that whilst the oil/oil emulsifier mixture is more toxic than the oil emulsifier alone, mixtures of oil with SDLT and BPX are significantly less toxic to the shore crab than an oil/Dispersant TS mixture; when comparable mixtures of oil with SDLT and BPX are used, it is the oil/SDLT mixture which is the less toxic. TABLE 6 The median tolerance limits of some marine animals exposed to 75% Kuwait crude oil 25% oil emulsifier mixtures. Species Carcinus maenas (shorecrab) Pholis gunnellus (gunnel)
TLm (ppm) Emulsifier Temp. °C 48 h LC~0 96 h LC~ BP 1002a 5-8 15.0 SDLT 20 3,550 BPX 20 800 SDLT 20 250 BPX 20 ~250b -
a P e r k i n s , 1968; b 7 5 % m o r t a l i t y
at 250 ppm.
Discussion A comparison of the new types of oil emulsifier SDLT and BPX with older types such as BP 1002, Slickgone, Petrofina Tarsolvent, shows that the former are very much less toxic than the latter to a variety of marine animals, including fish. It is also evident that when mixed with crude oil, the toxicity of the new oil emulsifiers is much lower than that of the older types; moreover, with respect to at least Carcinus, fears expressed that all oil/oil emulsifier mixtures will be about equitoxic is not confirmed, Considering first the short-term LC.~o experiments, it appears that the SDLT formulation alone and mixed with crude oil is rather less toxic than the BPX formulation alone or mixed with crude oil respectively. In the longer term, i.e. after the 5-day recovery period, the winkles L. saxatilis and L. littorea when released on the shore showed no evidence of a delayed mortality in the 28 days subsequent to treatment with SDLT. This is in marked contrast to the results of similar experiments performed with BP 1002. Moreover, a high mortality occurred only at the 5,000 ppm treatment with BPX. Although BP 1002 may inhibit growth of L. saxatilis at greater concentrations than 1/3,000 24 h LCs0 (Perkins, 1970), there is no evidence for an effect upon the fecundity of this species. A further encouraging result obtained with the SDLT emulsifier indicated that even when treated at 10,000 ppm growth o f the winkle L. saxatilis is not inhibited nor is fecundity obviously affected. Results with the oyster were less satisfactory, but they tend to corro-
borate the results obtained with L. saxatilis. Perhaps the most interesting feature of these results is the appreciation that it is possible to have surface active agents in which low toxicity and high efficiency are combined. Certainly in the early days after the wreck of the Torrey Canyon few felt confident that such results could be achieved. Condusiolk~ The oil emulsifiers SDLT and BPX are of low toxicity to a wide variety of marine animals. With respect to the standard bioassay organism Eupagurus bemhardus they are some three orders of magnitude less toxic than the type of oil dispersant used at the time of the Torrey Canyon disaster. Unlike the earlier disi3ersants, these low toxicity dispersants do not induce long-term effects upon the growth and mortality of treated animals. E . J . PE1Lr
Effects of an Oil Spill in the Northern Baltic Oil pollution from the tanker Palva which ran aground in Fina~h waters in 1969 provides an example of the hazards of oil spills in eoM waters. The Palva incident and its af~mmlth were studied by 1 ~ biologists and some of their findings are repoct~ here. The e l ~ casualties were eider ducks, bat fortunately long-term effects appear to have been small. The Archipelago Sea between the northern Baltic and the Bothnian Sea is an enormous jig-saw puzzle of sea intermingled with about twenty thousand pieces of land. Through this labyrinth of isles and skerries, among other cargoes, about 3 m tons of crude oil are carried yearly to an o ilrefinery near T urku in south-west Finland. When entering this 100 km passage inside the archipelago, the Finnish tanker Palva (15,600 dwt) ran aground on May 1, 1969 near K6kar (Fig. 1). Approximately 150 tons of Russian crude oil escaped into the sea. Floating oil could be observed at a distance of 25 km from the grounding place. There are not less than 500 isles and skerries in this area, most of which were protected from the oil spill by drive ice. Four days after the grounding, the shipowner started cleaning operations. Emulsifiers and absorbing in peat and burning were used in a three week clean-up period. A preliminary biological survey was made in the area in August 1969 by the Institute of Marine Research, Helsinki, and the Archipelago Research Institute
(University of Turku). The latter has, since 1970, carried out a series of field and laboratory studies on the effects of oil and the emulsifying chemicals used in connection with the grounding of the Palva. This work has been supported financially by the shipping company (Neste OY). ~(~J~ ~ ( ~ ~ a .~ ~ ( ~ / ~ ~
~' 0(~
~ 0q ~ ~0 ~ L "l " ~ 0 ~ ~ o, 0 ~ 0 t~-~. ~ E - / ~ 9 ~ ~3 (~t~ ~-~-'~
KOKAR ~ o,
o
, , , 5ok.,,
..
~ ~," ~-
* Fig. 1 The Archipelago Sea: the place of grounding of M/T Palva on May 1, 1969 (*) and the Archipelago Research Institute (ARI). OIIscrvation$ The first results of this field work in 1970 were recently published in A q u a Fennica, 1972. The most severe effects of oil pollution were on the eider population. It was estimated that 25-33% (2,400-3,000 birds) 93
Browning, E. (1961). Toxicity of Industrial Metals, Butterworths, London, England. location 4, western coast of Canada. Chapman, A. C. & Linden, H. (1926). On the presence of compounds of arsenic in marine crustaceans and shell fish. Minimum Median Maximum Analyst, 51: 563-564. No. of pg/g /~g/g /~g/g Dick, J & Pugsley, L. I. (1950). The arsenic, lead, tin, copper samples (wet (wet (wet and iron contents of canned clams, oysters, crabs, lobsters analysed weight) weight) weight) and shrimps. Can. J. Res., 28: 199-201. Marine invertebrates Ellis, M. M. (1934). Arsenic storage in game fish. Copeia, 2: 97. Fernandez del Riego, A. (1968). Determination of arsenic in Crab 9 2.4 6.6 14.0 marine fish. Bol. Inst. Espan. Oceanogr., 134. (Cancer magister) Fukai, R. & Meinke, W. W. (1959). Some activation analyses Clam 4 .~1.0 ~t.0 2.8 of six trace elements in marine biological ash. Nature, 1114: (Macoma sp.; 815-816. Clinocardium sp.) Johnels, A. G., Westtermark, T., Berg, W., Persson, P. I. & Marine fish Sjostrand, B. (1967). Pike (Esox lucius L) and some acquatic Rockfish 3 ~0.4 ~0.4 1.7 organisms in Sweden as indicators of mercury contamina(Sebastes sp.) tion in the environment. Oikos, 18: 323-333. Greenling 1 ~0.4 lrukayama, K. (1967). The pollution of Minamata Bay and (Hexagrammos sp.) Minamata disease. Adv. Water Pol. Res., 3: 153. Kurland, L. T., Faro, S. N. & Siedler, H. (1960). Minamata disease. The outbreak of a neurologic order in Minamata levels, such as fish, may be from the methylation of Japan, and its relationship to the ingestion of seafood arsenic by anaerobic bacteria present in marine sedicontaminated by mercuric compounds. World Neurol., 1: ments. McBride and Wolfe (1971) published data on the 370-395. LeBlanc, P. I. & Jackson, A. L. (1973). Dry ashing technique biosynthesis of dimethylarsine by cell extracts and for the determination of arsenic in marine fish. J. AOAC whole cells of 'Methanobacterium' strain M o l l , under (in press). McBride, B. C. & Wolfe, R. S. (1971). Biosynthesis of dimeanaerobic conditions, thylarsine by methanobacterinm. Biochem. 10: (23): The level of arsenic in shellfish, crustaceans, fresh4312-4317. water and marine fish used for food purposes should be Rucker, R. R. & Amend, D. F. (1969). Absorption and retention of organic mercurials by rainbow trout and chinook further investigated to document its distribution, and and sockeye salmon. Progressive Fish-Cult., 31: 197-201. since arsenic is highly toxic (As+ + +) it is important that Stratton, ,G. & Whitehead, H. C. (1962). Colorimetric deterits pathway through the aquatic environment and the ruination of arsenic in water with silver diethyldithiocarbamate. J. AWWA, 861-864. chemical form(s) concentrated by fish also be investi- Uthe, J. F. & Bligh, E. G. (1971). Preliminary survey of heavy gated, metal contamination of Canadian freshwater fish. J. Fish. Res. Bd. Can. 28: 5. P. J. LEBLANC Vasak, V. & Sedivec, V. (1952). Kolorimetrick~ stanoveni A. L. JACKSON arsenu. Chem. Listy, 46: 341-344. T,W. Beak Consultants Limited, Wobeser, G. N., Nielson, O., Dunlop, R. H. & Atton, F. M. (1970). Mercury concentrations in tissues of fish from the Toronto, Ontario, Canada. Saskatchewan river. I. Fish. Res. Bd. Can., 27: 830-834. Concentrations of arsenic in marine fish and invertebrates from
Oil Dispersant Toxicity Toxiefly tests nmktg a wide variety el shore animals reveal flint Iha ~teat gSmeralton of ~ have vetT l o w toxicity and no lonlPtetm eBeets, During the past five years, this laboratory has been concerned with the accurate assessment of toxic effects on marine animals, particularly invertebrates. The methods devised, although not regarded as other than an interim stage in the improvement of technique, have been described by Perkins (1972a, b). Both of these papers were concerned with the essentials of methodelegy; however, these methods have been developed during work upon a range of toxic substances which include oil dispersant formulations, and results obtained with oil dispersants are reported below, The test animals we have used have been selected on the basis of direct and indirect economic importance to inshore fisheries. The hermit crab Eupagurus bernhardus, a carnivorous species known to be highly sensitive to toxic materials, is an important fish food species upon which the basic screening of toxic materials is based in this laboratory. The oyster Ostrea, shrimp Crangon and plaice Pleuronectes platessa are important elements of estuarine and inshore fisheries, while sand flats are important nursery grounds for the latter. The shore crab Carcinus and the starfish Asterias are imp o n a n t predators of inshore fisheries and the former 9o
may contribute to the food of some fish, e.g. skate. The winkles Littorina spp. are among the most abundant of the littoral animals and, although resistant to toxic materials, are useful test animals because they m a y be marked and released to the shore after treatment; here their subsequent history--i.e, mortality and g r o w t h - may be studied. The edible periwinkles Littorina littorea are the subject of a fishery in some areas. The gunnel Pholis gunneUus is a fish which inhabits stony shores, seeks shelter beneath stones when the tide recedes and may therefore be affected directly by the consequences of an oil spill. The substances tested included a toxic standard (TS) of a formulation comparable with the highly toxic materials used at the time of the Torrey Canyon disaster, and two of the less toxic formulation developed since that time, viz. BP l l 0 0 X and Shell Dispersant LT, more briefly referred to as BPX and S D L T respectively below.
Methods The methods used were basically the determination of the 48 h LC~, at 20°C with a 5-day recovery period. Animals were always acclimated to laboratory conditions for at least a week before the beginning of laboratory tests. Departures from the standard 20°C were
made in those tests where large volumes o r m o r e space was required for the test animals. Subsequent to this determination, the animals used in the actual LC,0 test or in fresh and larger aliquots were maintained for prolonged periods in which a n y development of delayed mortality and any effect on growth was looked for. The fish Pleuronectes and Pholis were kept in the laboratory; L. littorea was released to the shore; Ostrea was transferred to live boxes at L o c h Sween. The Eupagurus from the highest dose in which 100% survived the 5-day recovery period were maintained individually in the laboratory, and the development of delayed mortality was examined. T h e methods employed are described by Perkins (1968, 1970, 1972a); the precautions necessary to the collection of test animals are described by Perkins (1972b).
Determiaatioas
T h e results of tests performed in this laboratory upon the earlier generation of oil-emulsifiers and the toxic standard are given in Table 1. It will be seen that the susceptibility of the individual species differs, but that the toxicity with respect to the sensitive Eupagurus bernhardus was of the order of 10 ppm. Delayed mortality effects occur in polychaete larvae (Wilson, 1968) and gastropod molluscs, viz. winkles and dogwhelks (Perkins, 1970), which had been treated with these materials, T h e results of the 48 h LC.~0 tests performed upon a n u m b e r of test animals with S D L T and B P X are given in Table 2. There are differences in the response of the individual species to the dispersants. Nevertheless, it will be noted that the toxicity of these formulations is significantly less than that of the earlier types. F o r example, the 48 h LCso of the toxic standard with respect to the sensitive Eupagurus bernh~dus was 11 p p m at 16°C, whereas that for S D L T and B P X exceeded 10,000 p p m at 20°C.
TABLE 2 The median tolerance limits of some marine animals with respect to Shell Dispersant LT (SDLT) and BPX. species
Temp. °C
Eupagurus bernhardus (hermit crab) Ostrea edulis (oyster) Crangon crangon (shrimp) Carcinus maenas (shore crab) Asterias rubens (starfish) Pleuronectes platessa (plaice) Solea solea (sole)
48 SDLT
h LC~0
BPX
20
~10,000
~10,000
20
~ 10,000
2,500
18
ca. 1,000
~l,000a
16.5-18.5
20,000
20,000
20
~6,000
16
~ 10,000
(i) 3,000 (ii)6,000 7,100
12.5-13.5
~10,0oo
-
aCrangon mortality in 1,000 ppm SDLT and BPX----55 and 10o% respectively. This result should be treated with caution since there were problems involved in the transport of this animal to the laboratory. N.B. The fish were not treated at 20°C because of the handling problems involved.
Long-termGrowth and Mortality Aliquots of L. littorea exposed for 24 h to doses of S D L T and B P X m u c h greater than 5,000 p p m were released to the shore (Table 3). In four weeks, neither group evinced a 50% mortality at the 5,000 p p m treatment and both formulations were rather less toxic to this species in the long term than BP1002. Nevertheless, at the 5,000 p p m dose B P X was markedly more toxic than SDLT. Recaptures in both these experiments were very g o o d and little mortality apparently developed at treatments below 5,000 p p m of either dispersant. The long-term effects, i.e. up to 28-29 days after treatment, of B P 1002 upon Littorina saxatilis are given in Table 4. In contrast, L. saxatilis exposed for 24 h to 5,000 p p m of S D L T suffered no mortality in the 5-day recovery period. I n large aliquots treated for 24 h at
TABLE 1 The median tolerance fimits of some marine invertebrates with respect to formulations typical of those used in the Torrey Canyon di~ster. Species
Formulation
Crangon crangon (shrimp) Eupagurus bernhardus (hermit crab)
BP 1002
Careinus maenas (shore crab) Littorina littorea (edible winkle) L. saxatilis (rough winkle) Thais (Nueella) lapillus (dog whelk) Mytilus edulis (mussel) Ostrea edulis (Oyster)
BP 1002 Dispersant TS Slickgone Petrofina TS BP 1002 BP 1002 Dispersant TS Slickgone BP 1002
6 h LCs0 16.0 -
-
-
8.0a 6.5a 60.0a 40.0a 80.0a ~3,000b (750 to ~3,000) 3,200b (400 to >3,200) 1,000b (150, 250, 1,000) 90, 320a
-
>640a
-
35-100 -
BP 1002
-
BP 1002
-
BP 1002 Slickgone Petrofina Dispersant TS
24 h LC~0
~800 ~5,120
~640a -
48 h LCs~ 96 h LC~0 5.8c
-
I 1.0 15c -
5.0a 29.0a -
-
-
-
-
-
2.5a -
aPerkins, 1968; bPerkins, 1968, 1970; cSimpson, 1968. Bracketed or multiple LCs0 result from paradoxical curves. 91
TABLE 3 The longer-term effects of a 24 h exposure of Littorina littorea to oil emulsifier formulations. All animals released to the shore subsequent to treatment, BP 1002a Dose (ppm) Control 7.5 30 190 750 3,000 21 Days recovery % Recaptured 40 42 41 29 32 38 % Cumulative mortality 0 0 0 3.0 l l.0 6.0 28 Days recovery % Recaptured 34 38 34 25 26 25 % Cumulative mortality 0 0 1.0 5.0 12.0 6.5 SDLT Dose (ppm) Control 50 500 5,000 23 Days recovery % Recaptured 44 91 73 93 % Cumulative mortality 0 0 1.0 0 27 Days recovery % Recaptured 55 98 88 96 % Cumulative mortality 0 1 1 0 BPX 23 Days recovery %
Dose (ppm) Control 50 500 5,000 44 0 55 0
Recaptured
% Cumulative mortality 27 Days recovery % Recaptured % Cumulative mortality aPerkins, 1970.
94 1 98 2
70 2 76 2
64 19 67 21
concentrations of SDLT up to 10,000 ppm, no noticeable mortality developed during one month after release to the shore. No significant differences in the growth and fecundity were noted between controls and animals treated to 10,000 ppm. TABLE 4 Long-term effeffcts of a 24 h exposure of Littorina saxatilis to BP 1002. All animals released to the shore subsequent to treatment (Perkins, 1970). Expt. $68 / 9 22 Days recovery % Recaptured % Cumulative mortality 29 Days recovery % Recaptured % Cumulative mortality Expt. $68/! 7 22 % % 28 % %
Control
Dose (ppm) 300 750 1,500 3,000
51 0
58 3
51 6
45 6
35 22
37 0
39 3
36 6
27 6
34 22
Dose (ppm)
Control 0.1 1.0 5.0 10 30 10o 300 Days recovery Recaptured 34 44 60 57 62 47 49 40 Cumulative mortality 0 0 3 2 2 3 2 11 Days recovery Recaptured 38 56 59 58 65 56 60 47 Cumulative mortafity 0 1 11 4 6 6 3 12
In general, those E u p a g u r u s subjected to all types of oil emulsifier formulation, old and new, did not show delayed mortality. Studies with the oyster Ostrea were affected by predation of the controls and treated animals alike. At the end of a 5-day recovery period there was no significant difference in mortality between the controls and the treated animals. In two experiments the mean mortality was about 5% (5% in controls; 3-8% in treated animals). On removal to Loch Sween, a high mortality developed in both groups--range 47% to 98%; controls 73% to 86%--during the following 1¼ years. Many of these 'dead' animals had completely disappeared (up to 69% per aliquot). Predation by the starfish ,4sterias was known to have occurred, and crabs 92
or a similar predator, are implicated where the total loss of shell occurred. These results have little value except that in 17, 33 and 64 weeks the predators apparently found treated animals to be neither more nor less palatable than the controls. In those animals which survived, and certainly at 17 weeks in experiment SC70/85, there was no evidence of retarded growth in the treated animals when compared with the controls. In connection with these experiments it should be noted that during 1969-70 the hatchery which was the source of test animals was troubled with high levels of zinc in their seawater source. A high hatchery death of oysters resulted and although an excessive mortality was not evident during acclimation and test here, these stocks gave trouble over the whole period 1969-71. The plaice used in these experiments were captured at Arisaig and transported to the laboratory by road. After treatment, they were maintained in the laboratory for 11 weeks during which period they were fed on mussel flesh (Table 5). During this period, mortality occurred in all groups, including the controls. At the end of the experiment, there was some evidence of the paradoxical effects which characterize detergents (Schatz et al., 1964), but at concentrations up to at least 1,000 ppm, survival of plaice treated with both SDLT and BPX was little different from that of the controls. At the highest concentration, viz. 10,000 ppm BPX was markedly more toxic than SDLT. TABLE 5 Long-term recovery of plaice, Pleuronectes platessa, exposed to 48 h treatments with SDLT and BPX (n. per aliquot= 16). % Survival Dose
SDLT BPX (48 h LC~=I0,000 ppm)(48 h LC~o=7,100 ppm) 1 week 11 weeks 1 week 11 weeks recovery recovery recovery recovery
Control 100 1,000 5,000 10,000
100 100 95 88 100
69 56 75 19 44
100 I00 100 95 0
69 50 75 38 0
Toxicity of Oil/Oil Dispersant M i x t u r e s A limited series of experiments were performed using 25% oil emulsifier/75% Kuwait crude oil mixtures. The results of these experiments are recorded in Table 6. It will be noted that whilst the oil/oil emulsifier mixture is more toxic than the oil emulsifier alone, mixtures of oil with SDLT and BPX are significantly less toxic to the shore crab than an oil/Dispersant TS mixture; when comparable mixtures of oil with SDLT and BPX are used, it is the oil/SDLT mixture which is the less toxic. TABLE 6 The median tolerance limits of some marine animals exposed to 75% Kuwait crude oil 25% oil emulsifier mixtures. Species Carcinus maenas (shorecrab) Pholis gunnellus (gunnel)
TLm (ppm) Emulsifier Temp. °C 48 h LC~0 96 h LC~ BP 1002a 5-8 15.0 SDLT 20 3,550 BPX 20 800 SDLT 20 250 BPX 20 ~250b -
a P e r k i n s , 1968; b 7 5 % m o r t a l i t y
at 250 ppm.
Discussion A comparison of the new types of oil emulsifier SDLT and BPX with older types such as BP 1002, Slickgone, Petrofina Tarsolvent, shows that the former are very much less toxic than the latter to a variety of marine animals, including fish. It is also evident that when mixed with crude oil, the toxicity of the new oil emulsifiers is much lower than that of the older types; moreover, with respect to at least Carcinus, fears expressed that all oil/oil emulsifier mixtures will be about equitoxic is not confirmed, Considering first the short-term LC.~o experiments, it appears that the SDLT formulation alone and mixed with crude oil is rather less toxic than the BPX formulation alone or mixed with crude oil respectively. In the longer term, i.e. after the 5-day recovery period, the winkles L. saxatilis and L. littorea when released on the shore showed no evidence of a delayed mortality in the 28 days subsequent to treatment with SDLT. This is in marked contrast to the results of similar experiments performed with BP 1002. Moreover, a high mortality occurred only at the 5,000 ppm treatment with BPX. Although BP 1002 may inhibit growth of L. saxatilis at greater concentrations than 1/3,000 24 h LCs0 (Perkins, 1970), there is no evidence for an effect upon the fecundity of this species. A further encouraging result obtained with the SDLT emulsifier indicated that even when treated at 10,000 ppm growth o f the winkle L. saxatilis is not inhibited nor is fecundity obviously affected. Results with the oyster were less satisfactory, but they tend to corro-
borate the results obtained with L. saxatilis. Perhaps the most interesting feature of these results is the appreciation that it is possible to have surface active agents in which low toxicity and high efficiency are combined. Certainly in the early days after the wreck of the Torrey Canyon few felt confident that such results could be achieved. Condusiolk~ The oil emulsifiers SDLT and BPX are of low toxicity to a wide variety of marine animals. With respect to the standard bioassay organism Eupagurus bemhardus they are some three orders of magnitude less toxic than the type of oil dispersant used at the time of the Torrey Canyon disaster. Unlike the earlier disi3ersants, these low toxicity dispersants do not induce long-term effects upon the growth and mortality of treated animals. E . J . PE1Lr
Effects of an Oil Spill in the Northern Baltic Oil pollution from the tanker Palva which ran aground in Fina~h waters in 1969 provides an example of the hazards of oil spills in eoM waters. The Palva incident and its af~mmlth were studied by 1 ~ biologists and some of their findings are repoct~ here. The e l ~ casualties were eider ducks, bat fortunately long-term effects appear to have been small. The Archipelago Sea between the northern Baltic and the Bothnian Sea is an enormous jig-saw puzzle of sea intermingled with about twenty thousand pieces of land. Through this labyrinth of isles and skerries, among other cargoes, about 3 m tons of crude oil are carried yearly to an o ilrefinery near T urku in south-west Finland. When entering this 100 km passage inside the archipelago, the Finnish tanker Palva (15,600 dwt) ran aground on May 1, 1969 near K6kar (Fig. 1). Approximately 150 tons of Russian crude oil escaped into the sea. Floating oil could be observed at a distance of 25 km from the grounding place. There are not less than 500 isles and skerries in this area, most of which were protected from the oil spill by drive ice. Four days after the grounding, the shipowner started cleaning operations. Emulsifiers and absorbing in peat and burning were used in a three week clean-up period. A preliminary biological survey was made in the area in August 1969 by the Institute of Marine Research, Helsinki, and the Archipelago Research Institute
(University of Turku). The latter has, since 1970, carried out a series of field and laboratory studies on the effects of oil and the emulsifying chemicals used in connection with the grounding of the Palva. This work has been supported financially by the shipping company (Neste OY). ~(~J~ ~ ( ~ ~ a .~ ~ ( ~ / ~ ~
~' 0(~
~ 0q ~ ~0 ~ L "l " ~ 0 ~ ~ o, 0 ~ 0 t~-~. ~ E - / ~ 9 ~ ~3 (~t~ ~-~-'~
KOKAR ~ o,
o
, , , 5ok.,,
..
~ ~," ~-
* Fig. 1 The Archipelago Sea: the place of grounding of M/T Palva on May 1, 1969 (*) and the Archipelago Research Institute (ARI). OIIscrvation$ The first results of this field work in 1970 were recently published in A q u a Fennica, 1972. The most severe effects of oil pollution were on the eider population. It was estimated that 25-33% (2,400-3,000 birds) 93