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Rehabilitation of oiled birds: A physiological evaluation of four cleaning agents
V o l u m e 2 0 / N u m b e r 1 0 / O c t o b e r 1989 0025-326X/89 $3.00+0.00 1989 PergamonPress plc
Marine Pollution Bulletin, Volume 20, No. 10, pp. 509-512, 1989. Printed in Great Britain.
Rehabilitation of Oiled Birds: a Physiological Evaluation of Four Cleaning Agents BJORN M U N R O JENSSEN and MORTEN EKKER
Department of Zoology, University of Trondheim, N-7055 Dragvoll, Norway
The development of more efficient detergents for cleaning oiled birds is important in order to improve on existing methods. In the present study we tested the properties of four different cleaning agents to remove oil from the plumage and to restore the water repellent and insulative properties of the feathers of domestic ducks (Anas platyrhynchos) and of common eiders (Somateria moilissima). By using more efficient detergents, the cleaning time was reduced by approximately 50%. Our results also show that these detergents are efficient in restoring the insulative properties of the cleaned plumage. The study also showed that the water repellent properties of the plumage were not re-established before the plumage was dry, and that cleaning oiled birds using cold water resulted in hypothermia.
For decades oiled seabirds have been rescued and rehabilitated (Beer, 1968; Naviaux & Pittman, 1973; Randall et al., 1980; Frink, 1982). By removing the oil from the plumage, it is possible to restore the water repellant microstructure of the feathers and therefore the insulative capacity of the plumage (Jenssen & Ekker, 1988). However, the process of cleaning oiled birds involves a lot of work and is time-consuming. Furthermore, large amounts of hot water are required, as well as storage facilities for both oiled and cleaned birds. Much effort has therefore been put into developing more efficient cleaning methods (Beer, 1968; Naviaux & Pittman, 1973; Randall et al., 1980; Frink, 1982). In order to develop a more efficient cleaning process for oiled birds we tested the effectiveness of four different cleaning agents using the methods described by Jenssen & Ekker (1988): metabolic heat production was measured while the birds were floating quietly on the water, inside a respiration chamber. Since any decrease in insulation results in an increase in metabolic heat production, this enabled us to evaluate the extent to which thermal insulation was restored after cleaning with the four different detergents. M a t e r i a l s and M e t h o d s
Experimental birds Seventeen domestic ducks (mean body weight (BW) = 3.59 + 0.42 kg) were purchased from a commer-
cial breeder (Svanoy Stiftelse, N-6965 .Svanoybukt, Norway), while nine common eiders (mean B W = 2.16 + 0.23) were caught in the Trondheimsfjord (63*26'N, 10"26'E). The eiders had been contaminated in another study dealing with effects of oil on thermoregulation in common eiders (Ekker & Jenssen, in prep.). Instead of sacrificing these birds, they participated in the present study and were released afterwards. Prior to and during the experimental period, the birds were housed indoors with access to a fresh-water pool (1 X3 × 1 m). The domestic ducks were kept under a 12L: 12D photo period, while the eiders were kept under light conditions corresponding to the local latitude and time of year (Feb.-April). The air temperature was kept at 5-10°C, and the water temperature at 4.5-6°C. The domestic ducks were given a diet of commercial breeding pellets, whilst the eiders were given an additional diet of blue mussels, (Mytilus edulis) and mashed fish. During the experiments, the domestic ducks and the common eiders were exposed to temperatures (air temperature equalled water temperature) of 21°C and 5°C, respectively. The ambient air and water temperatures were measured using thermocouples (Honeywell Standard, copper-constantan) and monitored continuously on a Leeds and Northrup recorder (Speedomax 165 S).
Metabolic heat production Oxygen consumption (VO2) was measured in an open-circuit system (Depocas & Hart, 1957) during the birds' activity phase. The birds were placed in a darkened respiration chamber (70 1.) filled with 25 1. of water. Air was pumped through the respiration chamber and dried with silica-gel and a fraction of it was passed into an oxygen analyser (Servomex Series 1100) for continuous determination of the 02 tension, which was recorded on a chart writer (Watanabe Servocorder, SR 6310). The air-flow through the respiration chamber (7-10 1. rain -1) was measured after each experiment, using a calibrated spirometer, or during the experiments using a calibrated flow-meter (Cole Parmer Instrument Company, FMO 34-39ST). The 02analyser was calibrated prior to each experiment, using atmospheric air (20.95% 02) and nitrogen (0% 02). 509
Marine Pollution Bulletin
The oxygen consumption was calculated according to the equation: V02 = VEX
FIOz--FEO2
1-- (1-RQ) X FIO 2
given by Withers (1977). V E is the airflow (ml STPD min -t) leaving the respiration chamber, FIO 2 and F E O 2 are the 02-fractions of the dry air respectively, entering and leaving the respiration chamber. RQ is the respiratory quotient, which was assumed to be 0.85. A real RQ of 0.7 or 1.0 would cause an error in the VO 2 of + 3%. Heat production (W kg -~) was calculated from the rate of oxygen consumption, assuming an energetic equivalent of 5.582 W kg -1 pr. ml 02 g-1 h-l. The oxygen consumption values used to calculate the heat production values were obtained during a 20 rain period after oxygen consumption had stabilized (at least 1 h after the start of each experiment).
To study whether the insulative properties of the plumage dependents on the feathers being dry, the metabolic heat production of three common eiders with damp plumages exposed to water, was measured 9 h after cleaning. To evaluate the possibilities of using efficient detergents in combination with cold water, two eiders were cleaned with OB-7, using water at 4 and 100C, respectively.
Results
Effects of oiling
Oil contamination of the domestic ducks resulted in an increase in metabolic heat production (Fig. 1) which was caused by the decrease in the thermal insulation of the plumage. The mean heat production of the domestic ducks prior to oil contamination was 4.35 W kg -l (n= 17, SD=0.52). The heat production of the ducks exposed to 500 ml of oil was significantly higher Oil-exposure of experimental birds (t=6.64, d f = 2 9 , P < 0 . 0 0 1 ) of 6.49 W kg -~ (n=14, After recording the metabolic heat production of SD=1.14). The mean heat production of the three normal, uncontaminated domestic ducks floating domestic ducks contaminated with 2000 ml of crude oil quietly in water the birds were contaminated (one at a was 11.38 W kg -l (n=3, SD=0.72), a significantly time) by placing them in a 70 1. chamber filled with 25 1. higher value (t=7.04, d f = 16, P < 0 . 0 0 1 ) than that of of water and 500 ml of Statfjord A crude oil. The birds the ducks contaminated with only 500 ml of oil. were allowed to remain for 30 min in the exposurechamber before being taken out and allowed to dry Effects of cleaning overnight. The experiments on the contaminated ducks All four detergents successfully removed the oil from were made on the following day. To find whether the the plumage of the domestic ducks. The heat producrestoration of plumage insulation was correlated to the tion of the ducks in all the cleaned groups decreased amount of oil on the plumage, three domstic ducks were significantly (t-test, P<0.025). contaminated with 2000 ml of crude oil. The common Using Zalo, the cleaning process lasted for 50-90 eiders were contaminated by injecting crude oil into the min. This was a relatively long cleaning time compared respiration chamber whilst the birds were floating to those of the other detergents, probably due to the quietly on the water surface. fact that Zalo proved more difficult to remove from the plumage. The heat production of these ducks was 4.97 Cleaning W kg -l (n = 5, SD = 0.71), significantly higher than that The oiled birds were subsequently soaped with one of the normal, non-oiled ducks (t=2.16, df--20, of four different cleaning agents (Zalo; A/S DeNoFa og P=0.043). Lilleborg Fabriker, Oslo, Norway. Taski-Profi; A. Sutler Two different amounts of oil (500 and 2000 ml) were A.G., CH 9542 MiJnchweilen, Switzerland. OB-5 and used to contaminate the ducks cleaned with Zalo. The OB-7; O. Bertelsen, N-1310 Blommenholm, Norway) results show that cleaning time was positively correlated in a sink filled with water (35-40°C). The detergent was with the amount of oil in and on the plumage. After removed from the plumage by a high-pressure waterjet from a hand-held shower. The time used for the entire cleaning process was recorded with a stop-watch. After cleaning, the birds were put onto a wire-mesh screen in a warm room (25-27°C) and allowed to dry overnight before the next experiments were conducted. To investigate the birds' energic costs of drying their water-saturated plumages, four cleaned eiders were placed, one at a time, in a large respiration chamber --r(200 1.) immediately after the cleaning process (a largesized chamber allowed the birds to preen freely). Silica gel was used to keep the humidity inside the respiration chamber low, and dry air was passed through the chamber at a rate of 10-15 1. min -1. The air temperature in the chamber was 25.4 (_+1.3)°C, and the birds were allowed to dry-out inside the chamber for 18 h, production of domestic ducks (Anas platyrhynchos) under while their oxygen consumption was monitored con- Fig. I Heat normal conditions, with oiled plumages, and with oiled tinuously. plumages cleaned with different detergents.
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Volume 20/Number 10/October 1989
cleaning, however, no difference in heat production was found between these two groups (t=0.48, d f = 4 , P=0.65). Taski-Profi removed the oil rapidly and efficiently from the plumage of domestic ducks. Like Zalo, Taskiprofi did not irritate the skin of the cleaners. The total cleaning-time using Taski-profi was 10-13 rain. Heat production values on the day after the cleaning procedure did not differ significantly from those of the normal, unoiled ducks (t=0.67, df = 18, P--0.513). Six ducks were cleaned using a cleaning agent (OB-5) especially developed for cleaning oiled birds. After cleaning and drying, their mean heat production, 4.30 W kg-~ ( n - 6 , SD=0.94), did not differ significantly from that of the normal, unoiled ducks (t=-0.99, df=21, P=0.333). Cleaning with OB-5 took 10-14 rain. However, OB-5 did irritate the skin of the cleaners and, we assume, also the skin of the ducks. Three domestic ducks were cleaned using a second detergent (OB-7) especially developed for cleaning oiled birds. This detergent did not irritate our skin. The mean heat production on the day after cleaning of ducks with OB-7 was 4.68 W kg-l ( n = 3 , SD=0.52). This value did not differ significantly from that of the normal, unoiled ducks (t= 0.99, df = 18, P = 0.333).
Cleaning in cold water The two common eiders that were cleaned with OB-7 using cold water (at 4 and 10°C, respectively) showed behavioural symptoms usually associated with hypothermia. The heat production on the day after cleaning of the eider cleaned using 4°C water was 435% higher than its heat production prior to oiling (3.31 W kg-~, while that of the eider cleaned using water of 10°C was 172% higher than its initial value (3.46 W kg-1). Energetic cost of drying The heat production of the four eiders placed in the large respiration chamber immediatelY after cleaning with OB-7 is shown in Fig. 2. When exposed to an air temperature of 25.4°C, heat production declined rapidly and reached the pre-oiling level after approximately 9 h. However, when three eiders which had been allowed to dry-out for 9 h were exposed to water (5°C), their metabolic heat production was 310-320% above the 12 ~1o
g 8; .g 6
g --v
2 0
~
0
2
i
4
6
-
f
,
i
8 10 Time (hours)
•
i
12
•
i
14
-
i
16
•
i
18
Fig. 2 Heat production of four oiled common eiders (Somateria rnollissima) for 17 h following cleaning with OB-7. The air temperature in the respiration chamber was 25°C. See text for further details.
level recorded for normal specimens (Jenssen & Ekker, 1988) exposed to the same temperature.
Discussion Exposure of the ducks to oil made the feather barbules adhere and allowed water to penetrate into the plumage leading to an increased loss of heat. To maintain a normal body temperature, the domestic ducks contaminated with 500 ml and 2000 ml of crude oil, respectively, increased their metabolic heat production by 81% and t32%, respectively. The effect of oil on the thermal properties of the plumage would thus seem to be dose-dependent. A similar dose-dependent response in oiled ducks exposed to air has previously been reported by Hartung (1967) and McEwan &,Koelink (1973). The plumage of the oiled ducks which were cleaned with Zalo was once more water repellent, but their metabolic heat production was significantly higher than that of normal, unoiled ducks. In a previous study (Jenssen & Ekker, 1988), only one of three oiled common eiders cleaned with Zalo showed normal metabolic heat production on the day after cleaning. The metabolic heat production of the ducks cleaned with the three other detergents, Taski-Profi, OB-5 and OB-7, did not differ significantly from that of the normal, unoiled domestic ducks. The water-repellent and insulative properties of the plumage of these birds were therefore assumed to have been fully restored. Thus, both OB-5 and OB-7 turned out to be more efficient than Zalo in restoring the insulative properties of the oiled plumage. The time taken to clean the birds with these detergents was approximately halved compared to Zalo. Taski-Profi, which is an industrial detergent especially developed to remove oil, seems to be the most preferable for restoring the insulative properties of the plumage of oiled ducks. Using cold water in combination with OB-7 clearly demonstrated that it was not possible to clean birds using cold water. It was difficult to remove the detergent from the plumage when rinsing with cold water and the long exposure to cold water caused the birds' body temperature to fall. Our results indicate that if cold water is to be used in the cleaning process, the detergent must be removed from the plumage within 1-3 min in order to prevent hypothermia. The plumage insulation of cleaned common eiders which had been allowed to dry-out for 9 h and still had a damp plumage, was not fully restored. In a previous paper (Jenssen & Ekker, 1988) we have shown that the plumage of a cleaned common eider which had driedout for 18 h did have the normal insulative property. Thus, the rehabilitation of the water repellent and insulative properties of the plumage seem to depend on the feather coat being fully dried-out. The drying-time probably depends on plumage thickness and may thus vary between species. An increase in air temperature, and in the rate of air passing the bird during drying-out would increase the rate of evaporation of water from the plumage and so reduce the rehabilitation time. Even though the common eiders were water-soaked 511
Marine Pollution Bulletin
after cleaning, and both their heat loss and heat production values were high during drying (at 25°C), the metabolic heat production never reached its maximum level which is approximately 20 W kg -1 (Jenssen & Ekker, 1988). During the drying process, healthy birds should thus not have any problem in producing enough heat to maintain a normal body temperature. The conclusion is that by using more efficient detergents, it is possible both to reduce the cleaning time and to improve the degree of restoration of the insulative properties of the cleansed plumage. The development of still more efficient cleaning agents for oiled birds is important, in order to improve on existing methods. Such an increase in efficiency would also help to increase the turnover-rate in the rehabilitation centre. The study was financed by the Norwegian State Oil Company (Statoil), as part of the project: "Evaluation of Cleaning Methods for Oiled Seabirds using Physiological Methods". The authors wish to thank the project leader Dr. Claus Bech, and K. H. Bryne and B. P. Nilsen from Statoil. The cleaning agents OB-5 and OB-7 were developed by O.
Bertelsen. N-1310 Blommenholm, Norway, who we also thank. Finally we thank P. Tallantire for correcting our English. Beer, J. V. (1968). The attempted rehabilitation of oiled sea birds. Wildfowl 19, 120-124. Depocas, F. & Hart, J. S. (1957). Use of the Pauling oxygen analyzer for measurements of oxygen consumption of animals in open-circuit systems and in a short-lag, closed-circuit apparatus. J. Appl. Physiol. 10,388-392. Frink, L. S. (1982). A new approach to oiled bird rehabilitation after oil spills on the East coast. In Land and water issues related to energy development (P. J. Rand, ed.), pp. 257-263). Ann Arbor Sci., Michigan, USA. Hartung, R. (1967). Energy metabolism in oil-covered ducks. J. WildL Manage. 31,798-804. Jenssen, B. M. & Ekker, M. (1988). A method for evaluating the cleaning of oiled birds. Wildl. Soc. Bull. 16,213-215. McEwan, E. H. & Koelink, A. C. (1973). The heat production of oiled mallards and scaup. Can. J. Zool. 51, 27-31. Naviaux, J. L. & Pittman, A. (1973). Cleaning of oil covered birds. BioL Conserv. 5,292-294. Randall, R. M., Randall, B. M. & Bevan, J. (1980). Pollution and penguins--Is cleaning justified? Mar. Pollut. Bull. 11,234-237. Withers, P. C. (1977). Measurements of VO,, VCO 2 and evaporative water loss with a flow-through mask. J. Appl. Physiol. Respimt. Environ. Exercise Physiol. 42,120-123.
MarinePollutionBulletin,Volume20, No. 10. pp. 512-523, 1989. Printedin Great Britain.
0025-326X/89 S3.00+0.00 © CrownCopyright1989
Metals and Organochlorines in Dolphins and Porpoises of Cardigan Bay, West Wales R. J. MORRIS*, R. J. LAW**, C. R. ALLCHIN t, CAROLE A. KELLY* and CATHERINE F. FILEMAN t *Cetacean Research Group, 4 Manwell Drive, Swanage, Dorset BH19 2RB; t Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research, Fisheries Laboratory, Burnham-on-Crouch, Essex CMO 8HA, UK *Author to whom correspondence should be addressed.
Concentrations of seven metals (Cr, Ni, Cu, Zn, Cd, Hg, and Pb) and a range of organochlorine pesticides, individual chlorobiphenyl congeners, and total polychlorinated biphenyis (PCB) have been determined in tissues of dolphins, porpoises, seals, and a variety of food chain species and sediments from Cardigan Bay, West Wales. Elevated concentrations of metals were not seen in any of the animal tissues examined. Higher than expected levels of organochiorine compounds were found in tissues of dolphins and porpoises; these concentrations are not derived from local pollution, but come from the animals' normal diet which did not show markedly elevated levels of organochlorines. The level of organochiorine bioaccumulation seen in some of the cetaceans analysed is much higher than found previously; this may have serious health implications for populations of those species around the coasts of NW Europe.
512
Declines in the populations of both common porpoises and bottlenose dolphins are reported to have occurred in the waters around the UK since 1940 (Evans & Scanlan, 1988). For porpoises this decline has been apparent in the North Sea in particular, but has also been noted in the Irish Sea and the English Channel. The bottlenose dolphin was never common in the North Sea, but there has been a general shift of distribution away from the northern Irish Sea, Bristol Channel, and the south coast of England. The main coastal populations of bottlenose dolphins remaining are in some of the least polluted areas, particularly those unaffected by discharge of untreated sewage (Evans & Scanlan, 1988). They generally remain close to the coast, 90% of sightings in the period 1958-85 being within 3 miles of land, compared with 79% for common porpoises and 0% for the striped (euphrosyne) dolphin (Evans etal., 1986).
Marine Pollution Bulletin, Volume 20, No. 10, pp. 509-512, 1989. Printed in Great Britain.
Rehabilitation of Oiled Birds: a Physiological Evaluation of Four Cleaning Agents BJORN M U N R O JENSSEN and MORTEN EKKER
Department of Zoology, University of Trondheim, N-7055 Dragvoll, Norway
The development of more efficient detergents for cleaning oiled birds is important in order to improve on existing methods. In the present study we tested the properties of four different cleaning agents to remove oil from the plumage and to restore the water repellent and insulative properties of the feathers of domestic ducks (Anas platyrhynchos) and of common eiders (Somateria moilissima). By using more efficient detergents, the cleaning time was reduced by approximately 50%. Our results also show that these detergents are efficient in restoring the insulative properties of the cleaned plumage. The study also showed that the water repellent properties of the plumage were not re-established before the plumage was dry, and that cleaning oiled birds using cold water resulted in hypothermia.
For decades oiled seabirds have been rescued and rehabilitated (Beer, 1968; Naviaux & Pittman, 1973; Randall et al., 1980; Frink, 1982). By removing the oil from the plumage, it is possible to restore the water repellant microstructure of the feathers and therefore the insulative capacity of the plumage (Jenssen & Ekker, 1988). However, the process of cleaning oiled birds involves a lot of work and is time-consuming. Furthermore, large amounts of hot water are required, as well as storage facilities for both oiled and cleaned birds. Much effort has therefore been put into developing more efficient cleaning methods (Beer, 1968; Naviaux & Pittman, 1973; Randall et al., 1980; Frink, 1982). In order to develop a more efficient cleaning process for oiled birds we tested the effectiveness of four different cleaning agents using the methods described by Jenssen & Ekker (1988): metabolic heat production was measured while the birds were floating quietly on the water, inside a respiration chamber. Since any decrease in insulation results in an increase in metabolic heat production, this enabled us to evaluate the extent to which thermal insulation was restored after cleaning with the four different detergents. M a t e r i a l s and M e t h o d s
Experimental birds Seventeen domestic ducks (mean body weight (BW) = 3.59 + 0.42 kg) were purchased from a commer-
cial breeder (Svanoy Stiftelse, N-6965 .Svanoybukt, Norway), while nine common eiders (mean B W = 2.16 + 0.23) were caught in the Trondheimsfjord (63*26'N, 10"26'E). The eiders had been contaminated in another study dealing with effects of oil on thermoregulation in common eiders (Ekker & Jenssen, in prep.). Instead of sacrificing these birds, they participated in the present study and were released afterwards. Prior to and during the experimental period, the birds were housed indoors with access to a fresh-water pool (1 X3 × 1 m). The domestic ducks were kept under a 12L: 12D photo period, while the eiders were kept under light conditions corresponding to the local latitude and time of year (Feb.-April). The air temperature was kept at 5-10°C, and the water temperature at 4.5-6°C. The domestic ducks were given a diet of commercial breeding pellets, whilst the eiders were given an additional diet of blue mussels, (Mytilus edulis) and mashed fish. During the experiments, the domestic ducks and the common eiders were exposed to temperatures (air temperature equalled water temperature) of 21°C and 5°C, respectively. The ambient air and water temperatures were measured using thermocouples (Honeywell Standard, copper-constantan) and monitored continuously on a Leeds and Northrup recorder (Speedomax 165 S).
Metabolic heat production Oxygen consumption (VO2) was measured in an open-circuit system (Depocas & Hart, 1957) during the birds' activity phase. The birds were placed in a darkened respiration chamber (70 1.) filled with 25 1. of water. Air was pumped through the respiration chamber and dried with silica-gel and a fraction of it was passed into an oxygen analyser (Servomex Series 1100) for continuous determination of the 02 tension, which was recorded on a chart writer (Watanabe Servocorder, SR 6310). The air-flow through the respiration chamber (7-10 1. rain -1) was measured after each experiment, using a calibrated spirometer, or during the experiments using a calibrated flow-meter (Cole Parmer Instrument Company, FMO 34-39ST). The 02analyser was calibrated prior to each experiment, using atmospheric air (20.95% 02) and nitrogen (0% 02). 509
Marine Pollution Bulletin
The oxygen consumption was calculated according to the equation: V02 = VEX
FIOz--FEO2
1-- (1-RQ) X FIO 2
given by Withers (1977). V E is the airflow (ml STPD min -t) leaving the respiration chamber, FIO 2 and F E O 2 are the 02-fractions of the dry air respectively, entering and leaving the respiration chamber. RQ is the respiratory quotient, which was assumed to be 0.85. A real RQ of 0.7 or 1.0 would cause an error in the VO 2 of + 3%. Heat production (W kg -~) was calculated from the rate of oxygen consumption, assuming an energetic equivalent of 5.582 W kg -1 pr. ml 02 g-1 h-l. The oxygen consumption values used to calculate the heat production values were obtained during a 20 rain period after oxygen consumption had stabilized (at least 1 h after the start of each experiment).
To study whether the insulative properties of the plumage dependents on the feathers being dry, the metabolic heat production of three common eiders with damp plumages exposed to water, was measured 9 h after cleaning. To evaluate the possibilities of using efficient detergents in combination with cold water, two eiders were cleaned with OB-7, using water at 4 and 100C, respectively.
Results
Effects of oiling
Oil contamination of the domestic ducks resulted in an increase in metabolic heat production (Fig. 1) which was caused by the decrease in the thermal insulation of the plumage. The mean heat production of the domestic ducks prior to oil contamination was 4.35 W kg -l (n= 17, SD=0.52). The heat production of the ducks exposed to 500 ml of oil was significantly higher Oil-exposure of experimental birds (t=6.64, d f = 2 9 , P < 0 . 0 0 1 ) of 6.49 W kg -~ (n=14, After recording the metabolic heat production of SD=1.14). The mean heat production of the three normal, uncontaminated domestic ducks floating domestic ducks contaminated with 2000 ml of crude oil quietly in water the birds were contaminated (one at a was 11.38 W kg -l (n=3, SD=0.72), a significantly time) by placing them in a 70 1. chamber filled with 25 1. higher value (t=7.04, d f = 16, P < 0 . 0 0 1 ) than that of of water and 500 ml of Statfjord A crude oil. The birds the ducks contaminated with only 500 ml of oil. were allowed to remain for 30 min in the exposurechamber before being taken out and allowed to dry Effects of cleaning overnight. The experiments on the contaminated ducks All four detergents successfully removed the oil from were made on the following day. To find whether the the plumage of the domestic ducks. The heat producrestoration of plumage insulation was correlated to the tion of the ducks in all the cleaned groups decreased amount of oil on the plumage, three domstic ducks were significantly (t-test, P<0.025). contaminated with 2000 ml of crude oil. The common Using Zalo, the cleaning process lasted for 50-90 eiders were contaminated by injecting crude oil into the min. This was a relatively long cleaning time compared respiration chamber whilst the birds were floating to those of the other detergents, probably due to the quietly on the water surface. fact that Zalo proved more difficult to remove from the plumage. The heat production of these ducks was 4.97 Cleaning W kg -l (n = 5, SD = 0.71), significantly higher than that The oiled birds were subsequently soaped with one of the normal, non-oiled ducks (t=2.16, df--20, of four different cleaning agents (Zalo; A/S DeNoFa og P=0.043). Lilleborg Fabriker, Oslo, Norway. Taski-Profi; A. Sutler Two different amounts of oil (500 and 2000 ml) were A.G., CH 9542 MiJnchweilen, Switzerland. OB-5 and used to contaminate the ducks cleaned with Zalo. The OB-7; O. Bertelsen, N-1310 Blommenholm, Norway) results show that cleaning time was positively correlated in a sink filled with water (35-40°C). The detergent was with the amount of oil in and on the plumage. After removed from the plumage by a high-pressure waterjet from a hand-held shower. The time used for the entire cleaning process was recorded with a stop-watch. After cleaning, the birds were put onto a wire-mesh screen in a warm room (25-27°C) and allowed to dry overnight before the next experiments were conducted. To investigate the birds' energic costs of drying their water-saturated plumages, four cleaned eiders were placed, one at a time, in a large respiration chamber --r(200 1.) immediately after the cleaning process (a largesized chamber allowed the birds to preen freely). Silica gel was used to keep the humidity inside the respiration chamber low, and dry air was passed through the chamber at a rate of 10-15 1. min -1. The air temperature in the chamber was 25.4 (_+1.3)°C, and the birds were allowed to dry-out inside the chamber for 18 h, production of domestic ducks (Anas platyrhynchos) under while their oxygen consumption was monitored con- Fig. I Heat normal conditions, with oiled plumages, and with oiled tinuously. plumages cleaned with different detergents.
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cleaning, however, no difference in heat production was found between these two groups (t=0.48, d f = 4 , P=0.65). Taski-Profi removed the oil rapidly and efficiently from the plumage of domestic ducks. Like Zalo, Taskiprofi did not irritate the skin of the cleaners. The total cleaning-time using Taski-profi was 10-13 rain. Heat production values on the day after the cleaning procedure did not differ significantly from those of the normal, unoiled ducks (t=0.67, df = 18, P--0.513). Six ducks were cleaned using a cleaning agent (OB-5) especially developed for cleaning oiled birds. After cleaning and drying, their mean heat production, 4.30 W kg-~ ( n - 6 , SD=0.94), did not differ significantly from that of the normal, unoiled ducks (t=-0.99, df=21, P=0.333). Cleaning with OB-5 took 10-14 rain. However, OB-5 did irritate the skin of the cleaners and, we assume, also the skin of the ducks. Three domestic ducks were cleaned using a second detergent (OB-7) especially developed for cleaning oiled birds. This detergent did not irritate our skin. The mean heat production on the day after cleaning of ducks with OB-7 was 4.68 W kg-l ( n = 3 , SD=0.52). This value did not differ significantly from that of the normal, unoiled ducks (t= 0.99, df = 18, P = 0.333).
Cleaning in cold water The two common eiders that were cleaned with OB-7 using cold water (at 4 and 10°C, respectively) showed behavioural symptoms usually associated with hypothermia. The heat production on the day after cleaning of the eider cleaned using 4°C water was 435% higher than its heat production prior to oiling (3.31 W kg-~, while that of the eider cleaned using water of 10°C was 172% higher than its initial value (3.46 W kg-1). Energetic cost of drying The heat production of the four eiders placed in the large respiration chamber immediatelY after cleaning with OB-7 is shown in Fig. 2. When exposed to an air temperature of 25.4°C, heat production declined rapidly and reached the pre-oiling level after approximately 9 h. However, when three eiders which had been allowed to dry-out for 9 h were exposed to water (5°C), their metabolic heat production was 310-320% above the 12 ~1o
g 8; .g 6
g --v
2 0
~
0
2
i
4
6
-
f
,
i
8 10 Time (hours)
•
i
12
•
i
14
-
i
16
•
i
18
Fig. 2 Heat production of four oiled common eiders (Somateria rnollissima) for 17 h following cleaning with OB-7. The air temperature in the respiration chamber was 25°C. See text for further details.
level recorded for normal specimens (Jenssen & Ekker, 1988) exposed to the same temperature.
Discussion Exposure of the ducks to oil made the feather barbules adhere and allowed water to penetrate into the plumage leading to an increased loss of heat. To maintain a normal body temperature, the domestic ducks contaminated with 500 ml and 2000 ml of crude oil, respectively, increased their metabolic heat production by 81% and t32%, respectively. The effect of oil on the thermal properties of the plumage would thus seem to be dose-dependent. A similar dose-dependent response in oiled ducks exposed to air has previously been reported by Hartung (1967) and McEwan &,Koelink (1973). The plumage of the oiled ducks which were cleaned with Zalo was once more water repellent, but their metabolic heat production was significantly higher than that of normal, unoiled ducks. In a previous study (Jenssen & Ekker, 1988), only one of three oiled common eiders cleaned with Zalo showed normal metabolic heat production on the day after cleaning. The metabolic heat production of the ducks cleaned with the three other detergents, Taski-Profi, OB-5 and OB-7, did not differ significantly from that of the normal, unoiled domestic ducks. The water-repellent and insulative properties of the plumage of these birds were therefore assumed to have been fully restored. Thus, both OB-5 and OB-7 turned out to be more efficient than Zalo in restoring the insulative properties of the oiled plumage. The time taken to clean the birds with these detergents was approximately halved compared to Zalo. Taski-Profi, which is an industrial detergent especially developed to remove oil, seems to be the most preferable for restoring the insulative properties of the plumage of oiled ducks. Using cold water in combination with OB-7 clearly demonstrated that it was not possible to clean birds using cold water. It was difficult to remove the detergent from the plumage when rinsing with cold water and the long exposure to cold water caused the birds' body temperature to fall. Our results indicate that if cold water is to be used in the cleaning process, the detergent must be removed from the plumage within 1-3 min in order to prevent hypothermia. The plumage insulation of cleaned common eiders which had been allowed to dry-out for 9 h and still had a damp plumage, was not fully restored. In a previous paper (Jenssen & Ekker, 1988) we have shown that the plumage of a cleaned common eider which had driedout for 18 h did have the normal insulative property. Thus, the rehabilitation of the water repellent and insulative properties of the plumage seem to depend on the feather coat being fully dried-out. The drying-time probably depends on plumage thickness and may thus vary between species. An increase in air temperature, and in the rate of air passing the bird during drying-out would increase the rate of evaporation of water from the plumage and so reduce the rehabilitation time. Even though the common eiders were water-soaked 511
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after cleaning, and both their heat loss and heat production values were high during drying (at 25°C), the metabolic heat production never reached its maximum level which is approximately 20 W kg -1 (Jenssen & Ekker, 1988). During the drying process, healthy birds should thus not have any problem in producing enough heat to maintain a normal body temperature. The conclusion is that by using more efficient detergents, it is possible both to reduce the cleaning time and to improve the degree of restoration of the insulative properties of the cleansed plumage. The development of still more efficient cleaning agents for oiled birds is important, in order to improve on existing methods. Such an increase in efficiency would also help to increase the turnover-rate in the rehabilitation centre. The study was financed by the Norwegian State Oil Company (Statoil), as part of the project: "Evaluation of Cleaning Methods for Oiled Seabirds using Physiological Methods". The authors wish to thank the project leader Dr. Claus Bech, and K. H. Bryne and B. P. Nilsen from Statoil. The cleaning agents OB-5 and OB-7 were developed by O.
Bertelsen. N-1310 Blommenholm, Norway, who we also thank. Finally we thank P. Tallantire for correcting our English. Beer, J. V. (1968). The attempted rehabilitation of oiled sea birds. Wildfowl 19, 120-124. Depocas, F. & Hart, J. S. (1957). Use of the Pauling oxygen analyzer for measurements of oxygen consumption of animals in open-circuit systems and in a short-lag, closed-circuit apparatus. J. Appl. Physiol. 10,388-392. Frink, L. S. (1982). A new approach to oiled bird rehabilitation after oil spills on the East coast. In Land and water issues related to energy development (P. J. Rand, ed.), pp. 257-263). Ann Arbor Sci., Michigan, USA. Hartung, R. (1967). Energy metabolism in oil-covered ducks. J. WildL Manage. 31,798-804. Jenssen, B. M. & Ekker, M. (1988). A method for evaluating the cleaning of oiled birds. Wildl. Soc. Bull. 16,213-215. McEwan, E. H. & Koelink, A. C. (1973). The heat production of oiled mallards and scaup. Can. J. Zool. 51, 27-31. Naviaux, J. L. & Pittman, A. (1973). Cleaning of oil covered birds. BioL Conserv. 5,292-294. Randall, R. M., Randall, B. M. & Bevan, J. (1980). Pollution and penguins--Is cleaning justified? Mar. Pollut. Bull. 11,234-237. Withers, P. C. (1977). Measurements of VO,, VCO 2 and evaporative water loss with a flow-through mask. J. Appl. Physiol. Respimt. Environ. Exercise Physiol. 42,120-123.
MarinePollutionBulletin,Volume20, No. 10. pp. 512-523, 1989. Printedin Great Britain.
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Metals and Organochlorines in Dolphins and Porpoises of Cardigan Bay, West Wales R. J. MORRIS*, R. J. LAW**, C. R. ALLCHIN t, CAROLE A. KELLY* and CATHERINE F. FILEMAN t *Cetacean Research Group, 4 Manwell Drive, Swanage, Dorset BH19 2RB; t Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research, Fisheries Laboratory, Burnham-on-Crouch, Essex CMO 8HA, UK *Author to whom correspondence should be addressed.
Concentrations of seven metals (Cr, Ni, Cu, Zn, Cd, Hg, and Pb) and a range of organochlorine pesticides, individual chlorobiphenyl congeners, and total polychlorinated biphenyis (PCB) have been determined in tissues of dolphins, porpoises, seals, and a variety of food chain species and sediments from Cardigan Bay, West Wales. Elevated concentrations of metals were not seen in any of the animal tissues examined. Higher than expected levels of organochiorine compounds were found in tissues of dolphins and porpoises; these concentrations are not derived from local pollution, but come from the animals' normal diet which did not show markedly elevated levels of organochlorines. The level of organochiorine bioaccumulation seen in some of the cetaceans analysed is much higher than found previously; this may have serious health implications for populations of those species around the coasts of NW Europe.
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Declines in the populations of both common porpoises and bottlenose dolphins are reported to have occurred in the waters around the UK since 1940 (Evans & Scanlan, 1988). For porpoises this decline has been apparent in the North Sea in particular, but has also been noted in the Irish Sea and the English Channel. The bottlenose dolphin was never common in the North Sea, but there has been a general shift of distribution away from the northern Irish Sea, Bristol Channel, and the south coast of England. The main coastal populations of bottlenose dolphins remaining are in some of the least polluted areas, particularly those unaffected by discharge of untreated sewage (Evans & Scanlan, 1988). They generally remain close to the coast, 90% of sightings in the period 1958-85 being within 3 miles of land, compared with 79% for common porpoises and 0% for the striped (euphrosyne) dolphin (Evans etal., 1986).