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Perceived and real risks: produced water from oil extraction
Marine Pollution Bulletin 44 (2002) 1171–1172 www.elsevier.com/locate/marpolbul
Editorial
Perceived and real risks: produced water from oil extraction
When the issue of the dumping of the oil tank ‘‘Brent Spar’’ was raging in the daily press in Europe the original argument was about whether the chemicals contained in the tank would leak out and pose a risk to marine life in the dumped area. Greenpeace had made a big issue of the chemicals but their estimate of amounts turned out to be a large overestimate. Yet the campaign gained momentum and the perceived risk to marine life in the end led to the boycott of Shell petrol stations and finally to the Brent Spar being cut up and made into a pier on the west coast of Norway! Yet the real risk to marine life from the chemicals was minimal or as one well-known marine biologist put it, ‘‘It is about the same amount of chemicals that leak from 500 m of newly asphalted road and no-one worries about the environmental effects of that, especially in the large amounts of water in the area of the proposed dump site!’’ Later the argument about whether or not to dump the Brent Spar became an issue of the principle of dumping, but initially it was about risk. The difference between perceived and real risk has recently been a major issue in Norway in relation to produced water from oil wells. As oil is extracted it gets more and more difficult to pump out the oil so seawater is injected to increase the amounts of oil that can be extracted from wells. The oil and water are pumped to the surface and after separation the seawater is discharged as produced water. Most wells in the southern North Sea are now reaching the end of their viable lives and so the amounts of produced water discharged are increasing rapidly. So the issue is what risk to marine life does this water pose? The Managing Director of the Norwegian State Oil Company Statoil said at a conference recently that there was no evidence that produced water was having any negative effects on marine life. Immediately there was an angry response from the Norwegian Fisheries Institute where one of their senior researchers stated that they had done laboratory experiments on effects of one of the chemicals in produced water, alkylated phenols, on cod and found that there were hormone disrupting effects. He attacked the Statoil chief saying this gave a bad signal to his workers with misinformation on the environment and how the oil
industry was affecting it. He further suggested that future exploration and oil extraction in the north of Norway needed better control from the state authorities. The problem, however, is that the Fisheries Institute scientist is equating a perceived risk with a real risk. All their research has shown is at a given concentration and over a given time span effects can be demonstrated. Yet are the concentrations that were shown to cause effects in the laboratory found in the field? Chemists from the same institute have taken samples of seawater near platforms discharging produced water and cannot measure the concentrations as they are below the limits of detection. Thus it is highly unlikely that such chemicals will affect cod, as they are exposed to extremely low concentrations if at all. So how do we assess the effects of produced water? In Copenhagen a couple of weeks ago a workshop was held (BECPELAG) reporting results of work done on effects of produced water (and a contaminant gradient from the Elbe estuary) using a wide variety of different biomarker techniques. Mussels, cod, and semi-permeable membranes were exposed for a period of 6 weeks, in large cages anchored at fixed distances from the oil platforms discharging produced water. Control cages were placed in areas not affected by produced water. Many different methods were tried, some showed high variability and thus it is unlikely that they showed statistically significant differences from controls. Other techniques were able to detect effects. But how do we interpret the results? Some biomarkers are called exposure biomarkers and indicate that the organism has been exposed to a certain chemical or group of chemicals. Other biomarkers indicate that the organism is affected by a contaminant and is responding to it. Yet the organism may well be able to cope with the contaminant at this level of exposure and no damaging effects result. Taking a worst-case scenario, as is appropriate with a precautionary approach, an effect biomarker suggests that after 6 weeks exposure in a cage there is a potential for damage to populations of mussels and cod. Now one has to take a risk assessment approach, rather than taking the raw results and crying wolf that ‘‘We have found effects of produced water!’’ The question is what
0025-326X/02/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 5 - 3 2 6 X ( 0 2 ) 0 0 3 5 7 - 0
1172
Editorial / Marine Pollution Bulletin 44 (2002) 1171–1172
is the risk to real populations in the field? Mussels, of course, do not occur in the water column of the open North Sea and so the risks to real populations of ecological or environmental significance do not occur. So it is more important to consider potential effects on fish. Firstly, one has to obtain an estimate of the exposure of the organisms. This is done by using knowledge of the amounts of contaminants in the discharged water, discharge and dilution rates and the calculated dispersal. Here one needs good hydrographic models that can integrate changing currents and dispersal at different depths can make predictions of concentrations over time. Yet such models have to be verified and validated. The problem is that many of the toxic components in the discharged produced water are at so low concentrations that they cannot be detected. So one has to use tracers that can actually be measured. From such data one can try to calculate the exposure to which the organisms were subjected. Thus linking cause (exposure) to effect (the biomarker) is extremely difficult. Then there is the problem of what is the risk that fish actually will be subjected to such exposure? Here one needs data on the behaviour of fish, will they be found in the area of the plume? and what percentage of the population is exposed? The dispersal model is important in this context and one also needs detailed knowledge of the biological systems in the water column. Without such data it will not be possible to estimate whether the perceived risk from the biomarkers
is in fact a real risk to the population. Such an approach has yet to be used and in fact application of risk assessment procedures to marine systems is still rather rare. What can we learn from the above and how is it relevant to managing the marine environment? I believe that it is extremely important in the context of costeffective management to distinguish between perceived and real risks. If one uses perceived rather than real risks as the basis for applying managerial controls on discharges one risks focussing on issues that may not in fact be important. The risks from produced water to ecologically or commercially important marine populations do not appear to be significant. In addition it is a publicly declared aim of the Norwegian oil industry to reach zero discharge of toxic chemicals to the sea within a period of 3 years. The industry has a very good record of reducing discharges to the Norwegian continental shelf and I am convinced that the target is achievable. Perhaps the Norwegian Fisheries Institute should instead focus their attention on applying risk analysis techniques to the exploitation of commercial fish stocks, where the risks are real rather than perceived. John S. Gray Department of Biology University of Oslo Pb 1064 Blindern 0316 Oslo, Norway
Editorial
Perceived and real risks: produced water from oil extraction
When the issue of the dumping of the oil tank ‘‘Brent Spar’’ was raging in the daily press in Europe the original argument was about whether the chemicals contained in the tank would leak out and pose a risk to marine life in the dumped area. Greenpeace had made a big issue of the chemicals but their estimate of amounts turned out to be a large overestimate. Yet the campaign gained momentum and the perceived risk to marine life in the end led to the boycott of Shell petrol stations and finally to the Brent Spar being cut up and made into a pier on the west coast of Norway! Yet the real risk to marine life from the chemicals was minimal or as one well-known marine biologist put it, ‘‘It is about the same amount of chemicals that leak from 500 m of newly asphalted road and no-one worries about the environmental effects of that, especially in the large amounts of water in the area of the proposed dump site!’’ Later the argument about whether or not to dump the Brent Spar became an issue of the principle of dumping, but initially it was about risk. The difference between perceived and real risk has recently been a major issue in Norway in relation to produced water from oil wells. As oil is extracted it gets more and more difficult to pump out the oil so seawater is injected to increase the amounts of oil that can be extracted from wells. The oil and water are pumped to the surface and after separation the seawater is discharged as produced water. Most wells in the southern North Sea are now reaching the end of their viable lives and so the amounts of produced water discharged are increasing rapidly. So the issue is what risk to marine life does this water pose? The Managing Director of the Norwegian State Oil Company Statoil said at a conference recently that there was no evidence that produced water was having any negative effects on marine life. Immediately there was an angry response from the Norwegian Fisheries Institute where one of their senior researchers stated that they had done laboratory experiments on effects of one of the chemicals in produced water, alkylated phenols, on cod and found that there were hormone disrupting effects. He attacked the Statoil chief saying this gave a bad signal to his workers with misinformation on the environment and how the oil
industry was affecting it. He further suggested that future exploration and oil extraction in the north of Norway needed better control from the state authorities. The problem, however, is that the Fisheries Institute scientist is equating a perceived risk with a real risk. All their research has shown is at a given concentration and over a given time span effects can be demonstrated. Yet are the concentrations that were shown to cause effects in the laboratory found in the field? Chemists from the same institute have taken samples of seawater near platforms discharging produced water and cannot measure the concentrations as they are below the limits of detection. Thus it is highly unlikely that such chemicals will affect cod, as they are exposed to extremely low concentrations if at all. So how do we assess the effects of produced water? In Copenhagen a couple of weeks ago a workshop was held (BECPELAG) reporting results of work done on effects of produced water (and a contaminant gradient from the Elbe estuary) using a wide variety of different biomarker techniques. Mussels, cod, and semi-permeable membranes were exposed for a period of 6 weeks, in large cages anchored at fixed distances from the oil platforms discharging produced water. Control cages were placed in areas not affected by produced water. Many different methods were tried, some showed high variability and thus it is unlikely that they showed statistically significant differences from controls. Other techniques were able to detect effects. But how do we interpret the results? Some biomarkers are called exposure biomarkers and indicate that the organism has been exposed to a certain chemical or group of chemicals. Other biomarkers indicate that the organism is affected by a contaminant and is responding to it. Yet the organism may well be able to cope with the contaminant at this level of exposure and no damaging effects result. Taking a worst-case scenario, as is appropriate with a precautionary approach, an effect biomarker suggests that after 6 weeks exposure in a cage there is a potential for damage to populations of mussels and cod. Now one has to take a risk assessment approach, rather than taking the raw results and crying wolf that ‘‘We have found effects of produced water!’’ The question is what
0025-326X/02/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 5 - 3 2 6 X ( 0 2 ) 0 0 3 5 7 - 0
1172
Editorial / Marine Pollution Bulletin 44 (2002) 1171–1172
is the risk to real populations in the field? Mussels, of course, do not occur in the water column of the open North Sea and so the risks to real populations of ecological or environmental significance do not occur. So it is more important to consider potential effects on fish. Firstly, one has to obtain an estimate of the exposure of the organisms. This is done by using knowledge of the amounts of contaminants in the discharged water, discharge and dilution rates and the calculated dispersal. Here one needs good hydrographic models that can integrate changing currents and dispersal at different depths can make predictions of concentrations over time. Yet such models have to be verified and validated. The problem is that many of the toxic components in the discharged produced water are at so low concentrations that they cannot be detected. So one has to use tracers that can actually be measured. From such data one can try to calculate the exposure to which the organisms were subjected. Thus linking cause (exposure) to effect (the biomarker) is extremely difficult. Then there is the problem of what is the risk that fish actually will be subjected to such exposure? Here one needs data on the behaviour of fish, will they be found in the area of the plume? and what percentage of the population is exposed? The dispersal model is important in this context and one also needs detailed knowledge of the biological systems in the water column. Without such data it will not be possible to estimate whether the perceived risk from the biomarkers
is in fact a real risk to the population. Such an approach has yet to be used and in fact application of risk assessment procedures to marine systems is still rather rare. What can we learn from the above and how is it relevant to managing the marine environment? I believe that it is extremely important in the context of costeffective management to distinguish between perceived and real risks. If one uses perceived rather than real risks as the basis for applying managerial controls on discharges one risks focussing on issues that may not in fact be important. The risks from produced water to ecologically or commercially important marine populations do not appear to be significant. In addition it is a publicly declared aim of the Norwegian oil industry to reach zero discharge of toxic chemicals to the sea within a period of 3 years. The industry has a very good record of reducing discharges to the Norwegian continental shelf and I am convinced that the target is achievable. Perhaps the Norwegian Fisheries Institute should instead focus their attention on applying risk analysis techniques to the exploitation of commercial fish stocks, where the risks are real rather than perceived. John S. Gray Department of Biology University of Oslo Pb 1064 Blindern 0316 Oslo, Norway