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How much heavy metal pollution?
September
1973
• Volume 4
• Number 9
How Much Heavy Metal Pollution? This issue of the Bulletin contains a number of articles which direct attention to additions of heavy metals to the marine environment. As a recent editorial pointed out (Marine Pollution Bulletin, 4 (7) : 97, 1973), this is a subject which comes to the public notice only when there is a particularly glaring case of what is thought to be excessive metal contamination of seafood. The officially acceptable levels of contamination are largely arbitrary, but even if they are probably extremely conservative as a rule, they are almost irrelevant. The extent of the human health hazard posed by metals depends on the total dietary intake, not the concentration, and the intake may come from a variety of sources which, as often as not, include far more significant ones than products from the sea. Since no-one shows injury or even discomfort from eating a tin of tuna with more than the officially approved mercury content, it is small wonder that the general public gets excited when a particularly dramatic news item hits the headlines, but otherwise is content to forget the whole thing. What else can it do, in any case? Metal pollution is therefore still more of research than public interest. At present research interest, at least at the receiver's end, is two-pronged. One approach, which is what the articles in this issue of the BMletin are mostly about, is concerned with discovering what metals and in what concentrations are accumulating in coastal waters, sediments and organisms. The other is to find out what effects metal contaminants have on aquatic organisms exposed to them: how and at what rate they accumulate and eliminate metallic compounds, and the effects short of death low concentrations of metals have on them. Scanning the title pages of any d u t c h of recent issues of marine biological journals will indicate the nature of this work. A few parts per million of copper in the water is sufficient to damage olfactory and other
sense organs in some fish and occasionally to cause brain haemorrhages in them. Concentrations a thousand times smaller reduce the swimming and feeding activity of brook trout. Methyl mercury accumulating in the body of roach and possibly also pike impairs the ability of these fish to right themselves. Eggs, larvae, fry and other juvenile forms usually prove to be much more susceptible than adult organisms. Metals which are cheerfully accumulated and stored by oysters and other shellfish as adults are lethal to the larvae in concentrations as low as a few parts per billion in the water. Similar low concentrations of mercury have been found to cause developmental abnormalities in salmon after exposure of the eyed eggs to the contaminant. Much of this sounds trivial enough and perhaps it is. The general argument about the sub-lethal effects of pollution is that anything that reduces an animal's efficiency by damaging its sense organs or interfering with its coordination, places it at a disadvantage in a competitive world, reduces its viability and one way or another results in an early death. Sub-lethal effects of this kind are no more than slightly delayed lethal effects. Alternatively, small doses of a contaminant may reduce the feeding and growth rate or the fecundity of an animal or the viability of its young. All of these consequences directly or indirectly reduce a natural resource which we might otherwise exploit. The loss of eggs or larvae, or the production of developmental abnormalities sounds more dramatic than the sub-lethal effects of these contaminants on adult animals. But in view of the enormous natural mortality of eggs and young, whether or not these losses matter in any economic sense is hard to assess. One has only to recall that the commercial salmon fishery throughout the world depends on catching a very large proportion of the fish on their spawning migration before they have spawned. The survivors manage to
Metals in the Sea Macmillan Journals Limited
60p U.K.
How much Heavy Metal Pollution?
page129
News Oil in Puget Sound
Soviet Sea Otters Increase JONSDAP in the North Sea Marine Pollution Monitoring
130 131 131 131
Reports Trace Metals in Sediments of New York Bight D. J. Carmody, J. B. Pearce and 14/.E. Yasso Trace Metals in the North Sea J. W. R. Dutton, D. F. Jefferies, A. R. Folkard and P.G.W. Jones Trace Metals in Carbonate and Organic Rich Sediments D. A. Segar and R. E. Pellenbarg Mercury in Fish and the News Media June Olley
132 135
138 143
Oil in Puget Sound
Correspondence Polystyrene Waste in the Severn Estuary
144
Conferences Oceans 2000 Australia's Law of the Sea
144 144
provide enough young to survive the normal tremendous hazards of life and still sustain the fishery in future years. Fortunately for us, natural mortality of most animals in the sea is on such a tremendous scale that the additional mortality imposed by human efforts is quite often negligible. The entire natural system has tremendous resilience but this euphoric view must not blind us to the fact that there must be a limit somewhere to what the natural environment can take before it begins to suffer. Where that limit is, how close we are to it, whether or not as the limit is approached the ecosystem will show a gradual deterioration or will suddenly deteriorate like the collapse of a house of cards, are all unknown. Much of the research into the more subtle effects of metals on organisms in the laboratory must be regarded as wasted effort until it is possible to say what significance the results have in the real world outside. Equally it is not too unkind to say that the fact that it is now possible to measure exceedingly low concentrations of metals with great accuracy has prompted a good many surveys of metal concentrations in coastal waters which really tell us very little. In neither the ecological nor the public health aspects of the dangers of metal pollution can it be said that very effective progress is being made. The problem is a difficult one and has something in common with assessing the dangers of radioactive waste disposal. Metals and radioactivity occur naturally and there is a natural input alongside the human input to the sea. Whatever damage is being done, whether to human health or the ecosystem, it is cumulative and takes a 130
long time to reveal itself. At the end of the day, the risks are what are euphemistically called 'only statistical'. We cannot escape all risks (in most countries it is statistically more dangerous to walk across the road than do anything else--except stay in bed where most deaths occur) and some kind of compromise has to be made. H o w much metallic waste should be released to the sea, how much dumped on land? H o w much money should be spent on extracting metal contaminants from effluents? Distasteful as it may be to have to produce firm figures, that is what has to be done if any rational policy of waste disposal is to be achieved. It is only stating the problem in another way to ask how much additional hazard in the sea is acceptable. Little of the current research is getting us nearer an answer to these questions.
Approval by large majorities of the Trans Alaska Pipeline System by the US Senate in July and the House of Representatives early in August marks the end of three years' delaying action by conservationists. They have lost a battle and although the outcome of this war can scarcely be in doubt, there are still a number of snags to be ironed out. Recurrent shortages or real-distribution of petroleum products in the United States which still results in garages having to turn away or ration customers from time to time, has no doubt swung public opinion sharply away from ecological preoccupations to the more immediate problem of keeping cars running. More dedicated conservationists see a dark plot by the oil companies and discount the reality of the shortages, but in one way or another they have lost sympathy and support as a result of them, The oil from the Alaska north slope will now be piped to Valdez on the south coast of Alaska and shipped by tanker to a refinery complex at Cherry Point in Puget Sound. At present Cherry Point handles tankers of up to 125,000 dwt but the enlargement of a deep water terminal to accept 250,000 ton tankers by 1975 is planned. There is also talk of ultimately using half-million or even million ton giants on this route. The fact that the sea route for the tankers, passing down the channel between Vancouver Island and the mainland, traverses Canadian waters introduces an international complication. The Provincial government of British Columbia is unenthusiastic about the project, to say the least. After the Bill to authorize the Alaska pipeline had been passed by Congress, the Minister of Agriculture of the Province protested to the State of Washington about the plans to build a deep water terminal at Cherry Point. He claimed that the flow of oil would bring no benefit to British Columbia but would greatly increase the risk of massive oil pollution in Canadian waters. A major oil spill was estimated to cost $29 million to clean up. Conservationists and others in the State of Washington are equally perturbed about these develop-
1973
• Volume 4
• Number 9
How Much Heavy Metal Pollution? This issue of the Bulletin contains a number of articles which direct attention to additions of heavy metals to the marine environment. As a recent editorial pointed out (Marine Pollution Bulletin, 4 (7) : 97, 1973), this is a subject which comes to the public notice only when there is a particularly glaring case of what is thought to be excessive metal contamination of seafood. The officially acceptable levels of contamination are largely arbitrary, but even if they are probably extremely conservative as a rule, they are almost irrelevant. The extent of the human health hazard posed by metals depends on the total dietary intake, not the concentration, and the intake may come from a variety of sources which, as often as not, include far more significant ones than products from the sea. Since no-one shows injury or even discomfort from eating a tin of tuna with more than the officially approved mercury content, it is small wonder that the general public gets excited when a particularly dramatic news item hits the headlines, but otherwise is content to forget the whole thing. What else can it do, in any case? Metal pollution is therefore still more of research than public interest. At present research interest, at least at the receiver's end, is two-pronged. One approach, which is what the articles in this issue of the BMletin are mostly about, is concerned with discovering what metals and in what concentrations are accumulating in coastal waters, sediments and organisms. The other is to find out what effects metal contaminants have on aquatic organisms exposed to them: how and at what rate they accumulate and eliminate metallic compounds, and the effects short of death low concentrations of metals have on them. Scanning the title pages of any d u t c h of recent issues of marine biological journals will indicate the nature of this work. A few parts per million of copper in the water is sufficient to damage olfactory and other
sense organs in some fish and occasionally to cause brain haemorrhages in them. Concentrations a thousand times smaller reduce the swimming and feeding activity of brook trout. Methyl mercury accumulating in the body of roach and possibly also pike impairs the ability of these fish to right themselves. Eggs, larvae, fry and other juvenile forms usually prove to be much more susceptible than adult organisms. Metals which are cheerfully accumulated and stored by oysters and other shellfish as adults are lethal to the larvae in concentrations as low as a few parts per billion in the water. Similar low concentrations of mercury have been found to cause developmental abnormalities in salmon after exposure of the eyed eggs to the contaminant. Much of this sounds trivial enough and perhaps it is. The general argument about the sub-lethal effects of pollution is that anything that reduces an animal's efficiency by damaging its sense organs or interfering with its coordination, places it at a disadvantage in a competitive world, reduces its viability and one way or another results in an early death. Sub-lethal effects of this kind are no more than slightly delayed lethal effects. Alternatively, small doses of a contaminant may reduce the feeding and growth rate or the fecundity of an animal or the viability of its young. All of these consequences directly or indirectly reduce a natural resource which we might otherwise exploit. The loss of eggs or larvae, or the production of developmental abnormalities sounds more dramatic than the sub-lethal effects of these contaminants on adult animals. But in view of the enormous natural mortality of eggs and young, whether or not these losses matter in any economic sense is hard to assess. One has only to recall that the commercial salmon fishery throughout the world depends on catching a very large proportion of the fish on their spawning migration before they have spawned. The survivors manage to
Metals in the Sea Macmillan Journals Limited
60p U.K.
How much Heavy Metal Pollution?
page129
News Oil in Puget Sound
Soviet Sea Otters Increase JONSDAP in the North Sea Marine Pollution Monitoring
130 131 131 131
Reports Trace Metals in Sediments of New York Bight D. J. Carmody, J. B. Pearce and 14/.E. Yasso Trace Metals in the North Sea J. W. R. Dutton, D. F. Jefferies, A. R. Folkard and P.G.W. Jones Trace Metals in Carbonate and Organic Rich Sediments D. A. Segar and R. E. Pellenbarg Mercury in Fish and the News Media June Olley
132 135
138 143
Oil in Puget Sound
Correspondence Polystyrene Waste in the Severn Estuary
144
Conferences Oceans 2000 Australia's Law of the Sea
144 144
provide enough young to survive the normal tremendous hazards of life and still sustain the fishery in future years. Fortunately for us, natural mortality of most animals in the sea is on such a tremendous scale that the additional mortality imposed by human efforts is quite often negligible. The entire natural system has tremendous resilience but this euphoric view must not blind us to the fact that there must be a limit somewhere to what the natural environment can take before it begins to suffer. Where that limit is, how close we are to it, whether or not as the limit is approached the ecosystem will show a gradual deterioration or will suddenly deteriorate like the collapse of a house of cards, are all unknown. Much of the research into the more subtle effects of metals on organisms in the laboratory must be regarded as wasted effort until it is possible to say what significance the results have in the real world outside. Equally it is not too unkind to say that the fact that it is now possible to measure exceedingly low concentrations of metals with great accuracy has prompted a good many surveys of metal concentrations in coastal waters which really tell us very little. In neither the ecological nor the public health aspects of the dangers of metal pollution can it be said that very effective progress is being made. The problem is a difficult one and has something in common with assessing the dangers of radioactive waste disposal. Metals and radioactivity occur naturally and there is a natural input alongside the human input to the sea. Whatever damage is being done, whether to human health or the ecosystem, it is cumulative and takes a 130
long time to reveal itself. At the end of the day, the risks are what are euphemistically called 'only statistical'. We cannot escape all risks (in most countries it is statistically more dangerous to walk across the road than do anything else--except stay in bed where most deaths occur) and some kind of compromise has to be made. H o w much metallic waste should be released to the sea, how much dumped on land? H o w much money should be spent on extracting metal contaminants from effluents? Distasteful as it may be to have to produce firm figures, that is what has to be done if any rational policy of waste disposal is to be achieved. It is only stating the problem in another way to ask how much additional hazard in the sea is acceptable. Little of the current research is getting us nearer an answer to these questions.
Approval by large majorities of the Trans Alaska Pipeline System by the US Senate in July and the House of Representatives early in August marks the end of three years' delaying action by conservationists. They have lost a battle and although the outcome of this war can scarcely be in doubt, there are still a number of snags to be ironed out. Recurrent shortages or real-distribution of petroleum products in the United States which still results in garages having to turn away or ration customers from time to time, has no doubt swung public opinion sharply away from ecological preoccupations to the more immediate problem of keeping cars running. More dedicated conservationists see a dark plot by the oil companies and discount the reality of the shortages, but in one way or another they have lost sympathy and support as a result of them, The oil from the Alaska north slope will now be piped to Valdez on the south coast of Alaska and shipped by tanker to a refinery complex at Cherry Point in Puget Sound. At present Cherry Point handles tankers of up to 125,000 dwt but the enlargement of a deep water terminal to accept 250,000 ton tankers by 1975 is planned. There is also talk of ultimately using half-million or even million ton giants on this route. The fact that the sea route for the tankers, passing down the channel between Vancouver Island and the mainland, traverses Canadian waters introduces an international complication. The Provincial government of British Columbia is unenthusiastic about the project, to say the least. After the Bill to authorize the Alaska pipeline had been passed by Congress, the Minister of Agriculture of the Province protested to the State of Washington about the plans to build a deep water terminal at Cherry Point. He claimed that the flow of oil would bring no benefit to British Columbia but would greatly increase the risk of massive oil pollution in Canadian waters. A major oil spill was estimated to cost $29 million to clean up. Conservationists and others in the State of Washington are equally perturbed about these develop-