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North Sea science
~4arine Pollution Bulletin, Volume 18, No. 6, pp. 257-258, 1987. Printed in Great Britain.
North Sea Science This spring has seen a flurry of reports assessing the health of the North Sea in the run-up to the interministerial conference on the North Sea which will be held in London next November. The similar meeting held in Bremen in 1984 ended inconclusively with the decision to collect together the scientific evidence before rushing into action to reduce the volume of wastes entering the sea.
The Water Research Centre organized an International Conference on the Environmental Protection of the North Sea which was held in London at the end of March (see Mar. Pollut. Bull. 18, 251). In April Greenpeace published its report on the North Sea rivers, (see Mar. Pollut. Bull. 18, 198), holding UK waste disposal practices responsible for most of the problems and predicting ecological catastrophe within a few years unless drastic action was taken. The most impressive document to appear, also in April, was the interim report of a Scientific and Technical Working Group set up following the Bremen meeting (which had little technical evidence before it) to provide a scientific assessment for the next interministerial meeting. What is impressive about the report is not so much its authoritative content but the fact that it was produced at all. Given the composition of the group--senior scientists reflecting official attitudes of the North Sea states--it has been possible to achieve a remarkable concensus about what is known and what is not. If delegates had national axes to grind (see this month's Viewpoint), they evidently became blunted in the course of examining the scientific evidence. The document does not make recommendations, that is a matter for politicians, but it is as near as we are likely to get to an objective view of the source and impact of wastes in the North Sea. The report is 'interim' to allow for additions that may be made in the light of assessments at present being made by ICES and the Oslo and Paris Commissions, which will become available this summer. They are not expected to result in any substantial change. One important fact confirmed in the report is that the North Sea cannot be regarded as a single unit, a point also to emerge from the WRC conference. As we have known for over 20 years, the hydrography is such that the North Sea is divided into a number of areas between which water exchange is very slow. In particular, coastal waters on both the east and west sides of the North Sea are relatively isolated from the main body of water. The main inputs are into the eastern side of the North Sea and this is where the greatest impacts a r e seen. Nutrient inputs and eutrophication are a major issue at present. 70-90% of nutrients enter via rivers, 50% contributed by the Rhine, and it is in the shallow coastal and internal waters of the eastern side of the North Sea that phytoplankton blooms have created
0025-326X/87 S3.01t+0.00 © 1987 Pergamon Journals Ltd.
problems in recent years. There has also been a change in the composition and phytoplankton in the North Sea which is sometimes attributed to pollution, but the same effect has been detected in other waters of the northeast Atlantic and is more likely to be due to climatic changes which are known to have occurred. Possibly a reduction of nutrient inputs to the eastern coastal waters will have a local remedial effect--Denmark has already started such a programme--but is unlikely to make much difference to the North Sea as a whole. Sea disposal of sewage sludge, practised almost uniquely by the UK, has often been attacked but it makes little contribution of nutrients to the overloaded coastal waters of the eastern North Sea. Sewage sludge dumping contributes only 5% of the metals entering the North Sea. Most enter from the atmosphere or the disposal of dredging spoils (between 40 and 70%, depending on the metal). Atmospheric inputs from vehicle exhaust, burning coal, etc. are widely dispersed, but inputs from contaminated dredgings are localized. Hamburg and Rotterdam have already adopted expensive alternative disposal routes for their most heavily contaminated dredgings to reduce metal pollution in the coastal waters of the continental side of the North Sea. The main input of radioactivity is from Sellafield, the discharge from which travels round the north of Scotland and down the eastern side of the UK. There is also an input from Cap la Hague through the Straits of Dover. This is not contentious, nor regarded as significant. The fact that the input from Sellafield has been halved in recent years and will be further reduced in the next year or two, has attracted little attention, but good news is not news so far as radioactivity is concerned. The one issue on which the report is cagey is the incidence of fish disease; a matter much emphasized in the Greenpeace report. All fish biologists accept that fish disease--papillomas, fin rot, etc.--occurs naturally in any fish population. Its incidence appears to increase in flatfish living in contaminated estuaries, but there is no strict correlation between the degree of contamination and the incidence of disease. So far as commercial fisheries are concerned, ICES and fishery biologists are convinced that fish disease, whether natural or pollution-induced, has no significant impact. It may well be that, as Greenpeace claims, 30% of flounders in the Thames estuary show pathological conditions. Considering that 20 years ago at the start of the Thames cleanup, there were no fish there at all, the existence of a large population, 70% of which are healthy, should be taken as a sign of the steady improvement of a previously lifeless area. There is also an incidence of pathological conditions in 70% of dabs in the southern North Sea. There is a difference of opinion about the relevance of pollution to this. It is an area of scientific ignorance and it is salutary for scientists to say clearly that we sometimes do not know. Nothing is served by scientific advisers feeling obliged to come to conclusions which the scientific evidence does not justify. We must now wait to see what political judgement emerges from the November ministerial consideration 257
Marine Pollution Bulletin
of the science. There will inevitably be compromises in view of the divergent approaches of the North Sea states: between the UK reluctance to throw large sums of money at problems which may not exist, the German pressure for precautionary measures just in c a s e . . . , the European Commission's wish to apply the same economic costs on all members of the Community, whether
UK Rebuttal to Dutch Claims on Offshore Pollution In a strongly worded statement the UK has criticized the conclusions drawn by authors of a Dutch paper presented at the WRC Conference on the Protection of the North Sea on 26 March 1987. The paper by Dr M. Scholten and J. Kuiper on Contaminants from Oil and Related Industries suggests that the offshore oil industry is the most important source of oil entering the North Sea contributing more than either shipping, land run off or atmospheric deposition. The authors cite figures, originally produced in a paper by Dr H. L. F. Saeijs of the Dutch Ministry of Transport and Public Works at the IAWPRC-TNO Conference on Fate and Effects of Oil in the Marine Environment held in February 1987 in Amsterdam, for oil pollution inputs to the North Sea: Source via atmosphere via run off (land) shipping offshore
Estimated Input to the North Sea (from Saeijs) 19 000-20 000 t 36 000-36 000 t 10 000-20 000 t 50 000-70 000 t
Immediately following the presentation of these estimates at the WRC Conference, however, David Bedborough of the UK Department of Energy made an official statement casting serious doubt on the validity of the data on inputs from the offshore industry and arguing that the conference should not treat these figures as 'scientific results' but rather speculation. Scholten and Kuiper claim that the total North Sea oil inputs from offshore operations comprise 2000 t from (oil in) produced water, 25 757 t from oil contaminated drill cuttings and 35 000 t from accidental spills. According to the authors inputs of oil in produced water will rise to 6000 t by 1989. These figures, however, disregard the recent assessments made by the Paris Commission (PARCOM) in preparation for the Second North Sea Conference. PARCOM estimates 4600 t for 1989 and as David Bedborough stressed the "predictions produced by PARCOM show that this figure will peak around 1995 at 5000 t and decrease thereafter". The UK Government's Brown Book (The Development of Oil and Gas Resources of the United Kingdom, 1987, HMSO) records a total of 166 accidental oil 258
they contribute to the problem or not. The final outcome will probably satisfy no-one completely, that is the nature of political compromises, but it is refreshing to have separated quite clearly the scientific assessment of sources and impacts of wastes in the sea from the political judgement of what to do about them. R. B. CLARK
spills from offshore operations during 1986, amounting to a total of 3540 t of oil spilled. There seems to be little doubt that increased surveillance and overflights have led to an increased number of spill incident reports which are now roughly double the total of approximately 80 incidents per year reported in previous years. The total amount of oil spilled, however, which includes the UK's largest ever spill since offshore operations began in the North "Sea, differ from corresponding Dutch estimates by almost an order of magnitude. Of the 3540 t spilled in 1986 on the UKCS some 3000 t are accounted for by the spill from the Piper/ Claymore pipeline (Mar. Pollut. Bull. 18, 58-59). Of the remaining 540 t there were 6 spills of over 25 t with 5 of these involving spills of oil-based mud. The largest in this category was made during an emergency to stabilize a drilling rig. Dr Saeijs' estimate of 35 000 t is extrapolated from the number and extent of oil slicks observed from spotter aircraft with the calculation of amounts in individual spills depending on a visual estimate of the thickness of the slick. North Sea states are cooperating in joint operations aimed at improving the scientific quantification of oil in individual slicks, but some contentious estimates have been hotly disputed. According to the UK Statement Dr Saeijs has acknowledged that his figures were highly contentious and produced for the purpose of provoking debate. In the statement made at the WRC Conference David Bedborough concluded that as there were serious flaws in the premises made by the authors it would be wholly unwarranted to support the conclusions which they draw. JONATHAN SIDE
Oil and Gas Discharges Review A short review of the control of discharges and environmental effects of oil and gas operations in the North Sea was given at the recent International Pollution Abatement Conference on 'The Technology of Environmental Protection' which was held from April 6-8 in Birmingham and sponsored by the Department of the Environment as part of the UK's contribution to the European Year of the Environment. In association with the conference an environmental protection exhibition opened at the National Exhibition Centre, near Birmingham. Speaking at the Conference, Dr Hugh Somerville, Head of Environmental Affairs for Shell UK Explora-
North Sea Science This spring has seen a flurry of reports assessing the health of the North Sea in the run-up to the interministerial conference on the North Sea which will be held in London next November. The similar meeting held in Bremen in 1984 ended inconclusively with the decision to collect together the scientific evidence before rushing into action to reduce the volume of wastes entering the sea.
The Water Research Centre organized an International Conference on the Environmental Protection of the North Sea which was held in London at the end of March (see Mar. Pollut. Bull. 18, 251). In April Greenpeace published its report on the North Sea rivers, (see Mar. Pollut. Bull. 18, 198), holding UK waste disposal practices responsible for most of the problems and predicting ecological catastrophe within a few years unless drastic action was taken. The most impressive document to appear, also in April, was the interim report of a Scientific and Technical Working Group set up following the Bremen meeting (which had little technical evidence before it) to provide a scientific assessment for the next interministerial meeting. What is impressive about the report is not so much its authoritative content but the fact that it was produced at all. Given the composition of the group--senior scientists reflecting official attitudes of the North Sea states--it has been possible to achieve a remarkable concensus about what is known and what is not. If delegates had national axes to grind (see this month's Viewpoint), they evidently became blunted in the course of examining the scientific evidence. The document does not make recommendations, that is a matter for politicians, but it is as near as we are likely to get to an objective view of the source and impact of wastes in the North Sea. The report is 'interim' to allow for additions that may be made in the light of assessments at present being made by ICES and the Oslo and Paris Commissions, which will become available this summer. They are not expected to result in any substantial change. One important fact confirmed in the report is that the North Sea cannot be regarded as a single unit, a point also to emerge from the WRC conference. As we have known for over 20 years, the hydrography is such that the North Sea is divided into a number of areas between which water exchange is very slow. In particular, coastal waters on both the east and west sides of the North Sea are relatively isolated from the main body of water. The main inputs are into the eastern side of the North Sea and this is where the greatest impacts a r e seen. Nutrient inputs and eutrophication are a major issue at present. 70-90% of nutrients enter via rivers, 50% contributed by the Rhine, and it is in the shallow coastal and internal waters of the eastern side of the North Sea that phytoplankton blooms have created
0025-326X/87 S3.01t+0.00 © 1987 Pergamon Journals Ltd.
problems in recent years. There has also been a change in the composition and phytoplankton in the North Sea which is sometimes attributed to pollution, but the same effect has been detected in other waters of the northeast Atlantic and is more likely to be due to climatic changes which are known to have occurred. Possibly a reduction of nutrient inputs to the eastern coastal waters will have a local remedial effect--Denmark has already started such a programme--but is unlikely to make much difference to the North Sea as a whole. Sea disposal of sewage sludge, practised almost uniquely by the UK, has often been attacked but it makes little contribution of nutrients to the overloaded coastal waters of the eastern North Sea. Sewage sludge dumping contributes only 5% of the metals entering the North Sea. Most enter from the atmosphere or the disposal of dredging spoils (between 40 and 70%, depending on the metal). Atmospheric inputs from vehicle exhaust, burning coal, etc. are widely dispersed, but inputs from contaminated dredgings are localized. Hamburg and Rotterdam have already adopted expensive alternative disposal routes for their most heavily contaminated dredgings to reduce metal pollution in the coastal waters of the continental side of the North Sea. The main input of radioactivity is from Sellafield, the discharge from which travels round the north of Scotland and down the eastern side of the UK. There is also an input from Cap la Hague through the Straits of Dover. This is not contentious, nor regarded as significant. The fact that the input from Sellafield has been halved in recent years and will be further reduced in the next year or two, has attracted little attention, but good news is not news so far as radioactivity is concerned. The one issue on which the report is cagey is the incidence of fish disease; a matter much emphasized in the Greenpeace report. All fish biologists accept that fish disease--papillomas, fin rot, etc.--occurs naturally in any fish population. Its incidence appears to increase in flatfish living in contaminated estuaries, but there is no strict correlation between the degree of contamination and the incidence of disease. So far as commercial fisheries are concerned, ICES and fishery biologists are convinced that fish disease, whether natural or pollution-induced, has no significant impact. It may well be that, as Greenpeace claims, 30% of flounders in the Thames estuary show pathological conditions. Considering that 20 years ago at the start of the Thames cleanup, there were no fish there at all, the existence of a large population, 70% of which are healthy, should be taken as a sign of the steady improvement of a previously lifeless area. There is also an incidence of pathological conditions in 70% of dabs in the southern North Sea. There is a difference of opinion about the relevance of pollution to this. It is an area of scientific ignorance and it is salutary for scientists to say clearly that we sometimes do not know. Nothing is served by scientific advisers feeling obliged to come to conclusions which the scientific evidence does not justify. We must now wait to see what political judgement emerges from the November ministerial consideration 257
Marine Pollution Bulletin
of the science. There will inevitably be compromises in view of the divergent approaches of the North Sea states: between the UK reluctance to throw large sums of money at problems which may not exist, the German pressure for precautionary measures just in c a s e . . . , the European Commission's wish to apply the same economic costs on all members of the Community, whether
UK Rebuttal to Dutch Claims on Offshore Pollution In a strongly worded statement the UK has criticized the conclusions drawn by authors of a Dutch paper presented at the WRC Conference on the Protection of the North Sea on 26 March 1987. The paper by Dr M. Scholten and J. Kuiper on Contaminants from Oil and Related Industries suggests that the offshore oil industry is the most important source of oil entering the North Sea contributing more than either shipping, land run off or atmospheric deposition. The authors cite figures, originally produced in a paper by Dr H. L. F. Saeijs of the Dutch Ministry of Transport and Public Works at the IAWPRC-TNO Conference on Fate and Effects of Oil in the Marine Environment held in February 1987 in Amsterdam, for oil pollution inputs to the North Sea: Source via atmosphere via run off (land) shipping offshore
Estimated Input to the North Sea (from Saeijs) 19 000-20 000 t 36 000-36 000 t 10 000-20 000 t 50 000-70 000 t
Immediately following the presentation of these estimates at the WRC Conference, however, David Bedborough of the UK Department of Energy made an official statement casting serious doubt on the validity of the data on inputs from the offshore industry and arguing that the conference should not treat these figures as 'scientific results' but rather speculation. Scholten and Kuiper claim that the total North Sea oil inputs from offshore operations comprise 2000 t from (oil in) produced water, 25 757 t from oil contaminated drill cuttings and 35 000 t from accidental spills. According to the authors inputs of oil in produced water will rise to 6000 t by 1989. These figures, however, disregard the recent assessments made by the Paris Commission (PARCOM) in preparation for the Second North Sea Conference. PARCOM estimates 4600 t for 1989 and as David Bedborough stressed the "predictions produced by PARCOM show that this figure will peak around 1995 at 5000 t and decrease thereafter". The UK Government's Brown Book (The Development of Oil and Gas Resources of the United Kingdom, 1987, HMSO) records a total of 166 accidental oil 258
they contribute to the problem or not. The final outcome will probably satisfy no-one completely, that is the nature of political compromises, but it is refreshing to have separated quite clearly the scientific assessment of sources and impacts of wastes in the sea from the political judgement of what to do about them. R. B. CLARK
spills from offshore operations during 1986, amounting to a total of 3540 t of oil spilled. There seems to be little doubt that increased surveillance and overflights have led to an increased number of spill incident reports which are now roughly double the total of approximately 80 incidents per year reported in previous years. The total amount of oil spilled, however, which includes the UK's largest ever spill since offshore operations began in the North "Sea, differ from corresponding Dutch estimates by almost an order of magnitude. Of the 3540 t spilled in 1986 on the UKCS some 3000 t are accounted for by the spill from the Piper/ Claymore pipeline (Mar. Pollut. Bull. 18, 58-59). Of the remaining 540 t there were 6 spills of over 25 t with 5 of these involving spills of oil-based mud. The largest in this category was made during an emergency to stabilize a drilling rig. Dr Saeijs' estimate of 35 000 t is extrapolated from the number and extent of oil slicks observed from spotter aircraft with the calculation of amounts in individual spills depending on a visual estimate of the thickness of the slick. North Sea states are cooperating in joint operations aimed at improving the scientific quantification of oil in individual slicks, but some contentious estimates have been hotly disputed. According to the UK Statement Dr Saeijs has acknowledged that his figures were highly contentious and produced for the purpose of provoking debate. In the statement made at the WRC Conference David Bedborough concluded that as there were serious flaws in the premises made by the authors it would be wholly unwarranted to support the conclusions which they draw. JONATHAN SIDE
Oil and Gas Discharges Review A short review of the control of discharges and environmental effects of oil and gas operations in the North Sea was given at the recent International Pollution Abatement Conference on 'The Technology of Environmental Protection' which was held from April 6-8 in Birmingham and sponsored by the Department of the Environment as part of the UK's contribution to the European Year of the Environment. In association with the conference an environmental protection exhibition opened at the National Exhibition Centre, near Birmingham. Speaking at the Conference, Dr Hugh Somerville, Head of Environmental Affairs for Shell UK Explora-