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Scientifically based strategies for marine environmental protection and management
Marine Pollution Bulletin, Volume 22, No. 9, pp. 432-440, 1991. Printed in Great Britain.
0025-326X/91 $3.00+0.00 O 1991 Pergamon Press plc
Viewpoint is a column which allows authors to express their own opinions about current events.
Scientifically Based Strategies for Marine Environmental Protection and Management JOHN S. GRAY*, D. CALAMARI, R. DUCE, J. E. PORTMANN, P. G. WELLS and H. L. WINDOM
The authors are all members of the UN Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP). This paper is the result of a GESAMP Working Group.
During the last decades, mankind has faced a wide range of environmental degradations: changes in climatic conditions and biogeochemical cycles, a number of ecoaccidents, the appearance of xenobiotics in remote areas and a general world-wide deterioration in environmental quality. The results in the aquatic environment were dramatic with effects such as massive fish kills and large areas of sea bed devoid of oxygen. Measures taken to protect the aquatic environment from such effects thus far have been based on strategies such as the Water Quality Standards, Black and Grey Lists and the Precautionary Principle. Recently, the so-called Brundtland report (World Commission on Environment and Development, 1987) postulated that a state of sustainable development was the ultimate goal to be reached by development and environment protection measures. The following are among the principles and responsibilities proposed by the Commission: • Conservation and Sustainable Use: States shall maintain ecosystems and ecological processes essential to the functioning of the biosphere, shall preserve biological diversity, and shall observe the principle of optimum sustainable yield in the use of living natural resources and ecosystems. • Environmental Standards and Monitoring: States shall establish adequate environmental protection standards and monitor changes in and publish relevant data on environmental quality and resource use. • Prior Environmental Assessments: States shall make *To whom correspondence should be addressed at Department of Marine Zoology, University of Oslo, P.O. Box 1064, 0316 Blindern, Oslo 3, Norway.
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or require prior environmental assessments of proposed activities which may significantly affect the environment or use of a natural resource. These new tasks and challenges, as well as new developments in science, make it necessary to re-consider existing strategies for the protection of the marine environment, and to propose new ones. It is, however, clear that in view of a number of global changes in the environment, e.g. climatic changes, measures to protect the marine environment cannot be taken in isolation but will also have to take into account other environmental compartments, e.g. land and air. As a first response to these challenges, this paper attempts to analyse current marine environmental protection strategies, identifying both their drawbacks and limitations and those elements of the scientific principles and management approaches that could be combined to provide a more comprehensive and effective framework for the protection of the marine environment, including its resources and amenities. The paper also provides an outline of such an overall framework that would provide an opportunity for the application of developments in scientific understanding to marine environmental protection and management.
Analysis o f existing aquatic environmental protection and m a n a g e m e n t strategies
Water Quality Standards Probably the earliest approach to environmental protection and management of aquatic systems involved the use of water quality standards or criteria. These continue to be widely used. However, many of these
Volume22/Number9/September1991 standards were first established decades ago, albeit on a scientific basis considered to be the best at the time (Alabaster & Lloyd, 1982). AS a result of the use of water quality standards in environmental management, most monitoring and surveillance programmes in aquatic systems have focused on the analysis of the concentration of potentially harmful substances in the water column. Because it is often not in the water column where the impact occurs, these programmes often lead to misperceptions of the problem or, even worse, failure to notice a problem until it is quite serious. Experience in the analysis of potentially harmful substances in the water column has shown that this is often difficult to perform precisely and accurately. As a consequence, past results of monitoring programmes, especially those involving several laboratories, have often either failed to detect changes when they have occurred or have indicated that water quality standards have been exceeded when they have not. These analytical difficulties have been generally overcome in developed countries by the introduction of new techniques and instruments, and by the implementation of quality assurance programmes. In developing countries, however, such improvements have not generally occurred, although many of these countries in principle use water quality standards in their aquatic environmental protection and management programmes. Existing water quality standards are mainly based on short-term bioassays of acute or lethal effects on test organisms that reside in the water column. The implied assumption is that the major compartment of the aquatic system in which the substance will accumulate, or at least have its impact, is the water column. The use of water quality standards usually does not take into account which species is the most sensitive to the substance. Furthermore, their use does not allow for the major impact that might arise due to the accumulation of the substance in one species which, although itself is unaffected, is fed upon another (e.g. man) which is affected. Another criticism of the past and present use of water quality standards in aquatic environmental protection and monitoring is that they are often applied ubiquitously to drastically different systems (e.g. freshwater and marine). This clearly does not take into consideration biogeochemical and ecological differences in aquatic systems, nor does it take into account the impact of multiple sources, i.e. overall load, nor does it take into account the impact of the substances in the areas of medium and long-term residence. In the past few years, however, considerably more has been learned about the biogeochemical behaviour of potentially harmful substances in aquatic systems and their toxicity to aquatic organisms. Current understanding of the biogeochemical behaviour of many potentially harmful substances (e.g. heavy metals, synthetic organics), however, indicates that they accumulate primarily in aquatic sediments. Thus there has been a change of emphasis way from simply defining water quality criteria to setting criteria for sediments (e.g. Baudo et al., 1990).
Black and Grey Lists The black and grey list approach divides substances into two groups. The first consists of substances that are regarded as so dangerous that they should not be allowed to enter the aquatic environment. The second group is considered less dangerous and such substances can be allowed to enter the aquatic environment, subject to certain precautions. The first group was intended to consist of substances that are highly persistent, highly toxic to one or more groups of organisms and strongly bioaccumulatable. The second group was expected to be characterized by low persistence, low toxicity and low bioaccumulation potential. Application of the concept has proved difficult for two main reasons: firstly, there is no clear dividing line between the groups. Secondly, when the lists were drawn up, substances were grouped together in one or other list according to the worst characteristics of some members of the group, however atypical of the whole group. It is now clear that the concept of two lists is in any event seriously flawed because the degree or persistence depends on environmental conditions which affect the behaviour of the substance .and the significance of both toxicity and bioaccumulation differs according to the target organisms. Thus, if status on a list is the sole criterion for decision-making, local conditions and biogeochemical behaviour a r e not taken into account. Furthermore, in its application little or no attention was paid to sources of the substances other than those involving direct discharge to the marine environment or to the cumulative effect of different sources at a local, regional or global level. Another weakness of the black and grey list approach is that they do not include the vast majority of organochlorines and other organics that are poorly or not described and yet are being discharged daily in industrial effluents. The black and grey list does not include chemicals that are released as complex mixtures, unless such mixtures are identified as a class of substances to be considered separately and controlled (e.g. organochlorine compounds in bleachery effluents). For these reasons, the black and grey list approach cannot be considered to be a properly developed scientifically based environmental management and protections system because it ignores particular circumstances that influence the risk the substances actually pose in a real situation. Nevertheless, the underlying idea that persistence, bioaccumulation and toxicity are important indicators of the likely hazard posed by a substance is scientifically sound.
The Precautionary Principle At the Second North Sea Conference, a new approach to environmental protection was adopted by acceptance of the precautionary principle (North Sea Conference, 1987). The precautionary principle is based on an earlier German initiative (Anon. 1986) but is a much simplified version of the original, which was a scientifically sound and logical document, (see Bewers (1989) for a review). The precautionary principle applies to substances that are persistent, toxic or bioaccumulatable but, in a highly significant departure from previous 433
Marine PollutionBulletin approaches, states that precautionary action should be taken, even without scientific evidence of cause and effect relationships, if the substance is suspected of having detrimental effects on the marine environment. In scientific terms, acceptance of this principle, especially defined in the terms used above, poses a number of fundamental problems (Gray, 1990). Firstly, the terms persistent, toxic and bioaccumulatable are not defined. At its most extreme all elements should be banned from discharge since they are persistent. Likewise, does toxic mean toxic to all marine species, and at what concentration or dose is a substance defined as 'toxic', as all chemicals will become toxic at sufficiently high levels? Some chemicals bioaccumulate naturally and yet pose no stress symptoms in the accumulating organism nor do they present health risks for other species consuming them. It is obvious that there is a strong case for both qualitative and quantitative definitions of these terms that will allow proper management of the marine environment and yet maintain the spirit of the precautionary principle. A second major criticism of the precautionary principle is the acceptance of suspicion of effects rather the scientific evidence as sufficient to introduce discharge controls. Providing that there are sufficient data available to make a thorough Hazard Assessment (see below) and providing that a sound monitoring strategy is in operation to test the predictions made, then only objective scientific evidence should be used for environmental protection and management purposes. As it stands, the precautionary principle can be invoked by simply arguing that at some future date a given chemical is likely to have an effect and discharge to sea therefore should be banned. Since the introduction of most substances to the marine environment will cause at least local disturbances and because effect is not defined, this argument can and is being invoked in relation to most sources of direct inputs to the marine environment. With a sound monitoring programme and with agreed limits for the discharge there should be little or no danger to the environment resulting from using only objective scientific criteria to judge whether or not limits have been exceeded. The precautionary principle does, however, have a role to play in cases where little is known about the chemical concerned or where the biogeochemical cycle and risks for the chemical in the environment are so poorly understood that a reasonably complete hazard assessment cannot be made and the critical load and monitoring targets cannot be identified. The precautionary principle has a further role in the introduction of environmental management in that it would argue against discharges where concentrations are approaching environmental quality standards and/or critical loads at all times and particularly in the early stages prior to the accuracy and predictions being proven.
Best Available Technology Whilst it may seem logical that one should employ the best available technology to minimize discharges of toxic 434
chemicals in order to protect the environment, there are problems with adopting this approach. In some circumstances the use of the best available technology may prove to be overprotective (e.g. a small discharge of a substance with limited persistence and toxicity made to a large receiving environment) or alternatively in other situations it may prove to be totally inadequate (e.g. discharge of a highly persistent and toxic substance made in large quantity to a small receiving environment or in smaller amounts but from several different sources to the same area). Whether or not the adoption of the best available technology should include an assessment of economic costs and/or the consequences for other environmental sectors is a controversial and much debated point. For example, Britain argues strongly for using the best available technology which does not entail excessive economic costs (BATNEEC), (see p. 138 of Anon. 1990). The use of the best available technology does, however, have a role to play in a fully developed environmental management and protection strategy, provided that comparison is made to the available alternatives and proper costings are done. This is because sound environmental management principles would advocate that inputs to the marine environment be kept as low as practicable, due account being taken of the consequences for other sectors of the environment.
The Montreal Guidelines The Montreal guidelines (UNEE 1985) are a set of recommendations to governments to assist them in development of legislation for the protection of the marine environment against pollution from land-based sources. The guidelines have taken common elements and principles from existing agreements such as the Oslo, Paris and Helsinki Conventions, the Athens protocol and the U N convention on the Law of the Sea. In annex 1 to the guidelines a section on strategies for protecting, preserving and enhancing the quality of the marine environment is presented. Firstly, there are control strategies such as those based on marine quality standards, emission standards and environmental planning. The marine quality guidelines consider standards based on water, sediment, fish or their tissues, health or community composition, but do not give a framework for deciding how the set of standards should be derived. It is suggested that no change over ambient concentration of a given substance should be used, but this does not take into account the fact that a given ambient concentration may not have any deleterious effects. Dilution and loads are also mentioned, but other important components of hazard assessment are not considered (see below). Under emission standards, technology standards are considered, and it is suggested that these should be applied on a sector by sector basis. A distinction is drawn between best practicable technology which takes into account costs and best available technology which does not, but which it is suggested should apply to the most noxious substances. Under planning strategies the guidelines recommend
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that certain activities are incompatible with the particular values or uses of the environment; that uses of the environment will have different quality standards and the standards should be defined for the specific uses; that environmental impact assessments are necessary for any activity affecting the environment; that regional management is needed for such areas as the coastal zone, drainage basins and specially sensitive areas. Thus, the guidelines give a useful checklist of factors that have to be considered but they do not provide a logical scientific framework for protection and management of the marine environment. It is this framework that will be developed in the following section.
Towards an integrated strategy The overall conclusions of this analysis indicate that an integrated framework for environmental protection and management is called for, (see also Calamari & Vighi, 1990). The fundamental idea that persistence, toxicity and bioaccumulation potential are key indicators of the potential hazard posed by a substance to the marine environment is scientifically sound. The same can be said of the concept of environmental capacity or critical environmental loads. What the currently adopted environmental protection strategies fail to provide for are variations in local circumstances and the biogeochemical behaviour of the substance once it is released into the environment. It is now clear that the latter, in particular, plays a vital role in determining both the actual impact of the substance and where that impact occurs.
precludes anything other than local scale effects still merit implementation of proper environmental management strategies. However, by the very nature of their effects, in most cases recovery of impacted environments will usually be rapid, e.g. within a few years in the case of most oil spills (Clark, 1982), as recolonization occurs from the surrounding unaffected area. During the seventies, when a shift from control to prevention took place, it was realized that control of conventional pollutants alone was an inadequate strategy. Three additional reasons emphasize the need for a different strategy in pollution control: 1. the need to protect the whole environment and not just one of the compartments (water, air, land) or a single identified target species; 2. the huge quantity of information necessary to formulate quality criteria for any environmental compartment, and 3. the great number of chemical substances actually used by man as well as the variety of chemical groups to which these substances belong, (OECD, 1986). It is clear from the preceding discussion that many of the old approaches to marine environmental protection and management must be augmented by new ones which taken into account our improved understanding of natural aquatic systems. The following sections describe several essential components of an integrated framework for the protection and management of the marine environment that integrate new scientific developments with past experience. Figure 1 shows a diagrammatic outline of the new strategy which is directed towards the prediction of impacts of chemicals in the marine environment.
Thus, whilst problems may be caused at a local level by excess inputs of virtually any chemical substance, the Hazard Assessment extent to which they occur at a regional level depends At the conclusion of a symposium of the American upon the degree to which a chemical remains in the Society for Testing and Materials on Estimating the water column or is transported away from the source of Hazard of Chemical Substances to Aquatic Life, Cairns et input via sediment mobilization mechanisms. Examples al. (1978) stated that: "a hazard assessment to measure of such problem-causing substances are certain metals, the risk must ultimately be based upon sound scientific nutrients and oils. A few substances, through their judgement applied to knowledge of expected environextreme volatility or persistence, may be capable of mental concentration of the material and the material's causing effects on a global scale even though the source toxicological properties". This simple concept highlights of their introduction is limited to particular areas. the importance of exposure and the fact that a toxicoExamples of such substances and problems are PCBs, logical criterion is only part of the pollution control the greenhouse gases and acid rain. Chemicals that have strategy. Furthermore, it highlights the difference a potential to cause effects on a regional scale also merit between the hazard potential of a substance and the early attention since recovery of the environment on a actual risk of a problem being caused as a consequence regional scale is likely to take years and will usually of exposure to the hazard. involve development of mechanisms for coordinating In the last ten years, the capability for environmental action on a multi-national level. management of chemicals has greatly increased due to The substances most urgently meriting control are the the availability of conceptual approaches and technical latter group, since by the very scale of their potential tools developed by the scientific community. The two effects control will be difficult and recovery slow. One of most relevant conceptual frameworks, not yet fully the difficulties to be faced is likely to be a conflict of explored and exploited, are the assimilative capacity, interest between the developed and developing nations. which is defined as "the ability of a receiving system or The former group are most likely to seek desired ecosystem to cope with certain concentrations or levels environmental improvements whereas the latter group of waste discharges without suffering any significant may attach more importance to the benefit, in the deleterious effects" and the hazard assessment approach economic, agricultural or human health protection (previously defined) both orginally proposed by Cairns terms, provided by continued use and release of the 1977) and Cairns et al. (1978). These two approaches chemical. have been successively developed by several authors; Those chemicals whose biogeochemical behaviour see for example in relation to assimilative capacity the 435
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[ PRODUCTION, USES, DISCHARGE PAqTERNS, LOADS, SOURCES I PHYSICO-CHEMICAL ~ . . , ~ PROPERTIES
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ASSESSMENT I OF LIKELY EFFECTS
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PREDICTION OF LIMITS OF EFFECT OR CONCEN. ~1 MONITOR I I ARE PREDICTION LIMITS EXCEEDED ]
Fig. 1 An integrated approach for the study of marine pollution (The hazard assessment procedure).
GESAMP report on Environmental capacity. An approach to marine pollution prevention (GESAMP, 1986) and for hazard assessment the Scandinavian experience extensively described by Lander (1988). It should be noted that far from seeking to use the environments' resilience to the full, the environmental capacity approach in effect seeks, first to define the critical load; then, in its application seeks, not just to avoid exceeding the defined limits, but to keep actual inputs as far as practicable below this. Any kind of evaluation for a potentially harmful chemical substance must taken into account two types of factors, the first intrinsic with the substance, the second 436
related to the extrinsic conditions and their reciprocal interactions (Wells & Cot6, 1988; Vighi & Bacci, 1989). Basically, the necessary parameters belong to seven classes: • quantity: production, uses, discharge patterns, loads, sources; • distribution: physico-chemical characteristics, affinity for environmental compartments, sinks; • persistence: kinetics of hydrolysis, photolysis, biodegradation; • bioaccumulation: n-octanol/water partition coefficient, metabolic pathways in different organisms;
Volume22/Number9/September1991 • toxicity: measures of biological activity of the substance (ideally from cells to ecosystems); • ecosystem typologies: biotic and abiotic characteristics and structure and functions of ecosystems. • targets of exposure: considerations about the vulnerability and stability of (a) potential target communities and (b) life cycle stages of potential target species. Obviously consideration must also be given to the time scale of the events. Up to now, great importance has only been attributed to three of these parameters (toxicity, bioaccumulation, persistence) e.g. the North Sea Declaration (1987) and although limited attention has recently been given to the loads (particularly from land-based sources) these have rarely been correctly quantified. The seven classes listed above incorporate many new research findings concerning physico-chemical and biological properties, mass balance models, etc. Physico-chemical Properties There is growing recognition of the importance of atmospheric inputs of chemicals to the marine environment. Recent calculations reveal that global input from the atmosphere dominates riverine input for the metals lead, cadmium and zinc as well as for most high molecular weight chlorinated hydrocarbons, whereas atmospheric and riverine inputs are similar for copper, nickel, arsenic, iron, nitrogen and phosphorus (GESAMP, 1990). There have been marked improvements in the laboratory determination of Henry's Law Constants and gas exchange coefficients necessary to model the air/sea exchange of gaseous pollutants, (Mackay et al. 1986; Bidleman, 1988; Buat-Menard, 1986). Through knowledge of the kinetics of hydrolysis, photolysis and data on biodegradation rates of chemicals it is possible to predict their persistence in the environment (Hutzinger, 1982 a,b). Likewise the soil sorption partition coefficient can provide substantial information on physical movements of hydrophobic chemicals (Karichoff et al., 1979) and have been used to rank chemicals for ground water contamination (Rao et al., 1985) and should have relevance in the marine environment. Studies of biogeochemical cycles of estuarine and continental shelf systems during the past two decades have greatly increased our understanding of how processes within these systems affect the fate and flux of contaminants delivered to the marine environment. If one assumes that these systems along with continental slopes constitute the ocean margin, it has been estimated that more than 95% of the nitrogen delivered by rivers accumulates in this region. Thus, increased mobilization of nitrogen on land may have major impacts in ocean margins. Yet the processes are complex in some areas. Although nitrate levels have increased in rivers the same has not occurred in coastal areas due to biological removal and loss by denitrification and ammonia production. Because of the particle reactivity of most pollutants, the ocean margin, not the deep ocean, is the ultimate sink for most river-transported contaminants. In fact,
recent evidence suggests that ocean margins may als0 be a major sink for materials from the open ocean. For example, plutonium, which is delivered to the ocean primarily through the atmosphere, accumulates disproportionately in ocean margins. Lead and other anthropogenically mobilized substances, primarily transported by the atmosphere, may behave similarly. Having obtained data on quantities of material discharged, on physico-chemical properties, and on the environment one can proceed to an evaluative model. The role of mass-balance models and other components The next phase is the construction of a mass balance model since this will serve to confirm that all sources and sinks have been accounted for. One of the most effective and simplest of these has been the VoUenweider model for treatment of lake eutrophication (Vollenweider, 1975, and more recent modifications Reckhow & Chapman, 1983). The model has been successfully applied in many different geographical areas. Yet in some cases the model predictions have not been borne out. It is now realized that different biological structures in lake ecosystems have important consequences for phosphorus cycling. Thus, to obtain more exact management tools it is necessary to understand phosphorus cycling under systems with different biological structures. There are few other models that have been as successful as the Vollenweider model. One goal of future research, therefore, should be to find other models which can be used in a marine context, (see e.g. Tateya et aL, 1988). There is an urgent need for models for nitrogen and phosphorus in relation to marine eutrophication problems but it is unlikely that the simplicity of the Vollenweider approach can be as successful in the complexity of the marine environment. Biological properties The prediction of effects has been made possible by means of studies on quantitative structure activity relationships (QSAR) in ecotoxicology, (Calamari & Vighi, 1989; Hermens, 1989). QSARs have been developed for several classes of chemicals and allow within these classes, good estimates of the toxicity of chemicals. However, QSARs have been applied to a limited number of chemicals and some expert judgement is still required to determine the boundaries of toxicological predictability when using the QSAR approach. Nevertheless if experimental toxicological data are unavailable, QSARs can be applied within heterogeneous groups of chemicals and do offer a basis for some predictability, certainly in respect to selecting priority substances. Toxicity testing has also advanced greatly in recent years with development of new and more standardized tests (Blaise et al., 1988). The n-octanol/water partition coefficient has been demonstrated to be a useful parameter to predict the potential for bioaccumulation of chemical substances in several organisms (Veith et al., 1979; Bacci et al., 1989) and should be further studied in marine organisms. Advances in biological effects monitoring techniques 437
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using, for example, physiological techniques such as 'scope for growth' of bivalve mussels, mixed function oxygenase (MFO) enzyme systems in fish, metallothionein detoxification systems in fish and new multivariate analysis techniques for benthic communities have been shown to distinguish fine gradients of pollution effects that were not detectable a decade ago (Bayne et aL, 1988).
Prediction of impacts The hazard assessment process should yield clear predictions of: • the transport pathways and rates, • the likely environmental compartment (water, sediment and/or biota) where the substance/material is likely to accumulate, • the chemical composition and concentration of the substance, and • the likely impact of the substance/material at a given target site or on a given organism or set of organisms. For example, one could predict from its biogeochemical characteristics that the concentration of a chemical is not likely to increase in a given compartment by more than a certain percentage over background levels (it is assumed that the given percentage increase over background is detectable by the sampling and analysis procedures available and would not induce detrimental effects on biological system). The background levels together with natural sampling and analysis variability would be given. Any statistically significant increase by more than the given percentage over background would trigger a feedback loop on the discharge concession. Predictions should not only be made of chemical concentrations but also of any expected biological effects. Clearly stated limits to changes in either a stress response of a given species and/or a community response should be made. If statistically significant changes over the prediction are found then again this should trigger the feed-back loop on the discharge concession with the questions: are the effects observed acceptable or why were they not predicted? Such a priori predictions require that monitoring is done with the best available techniques and is targeted specifically at sites and/or organisms that can be expected to show effects. In setting discharge limits it is important to specify statistical limits above which a given fraction of samples is allowed to exceed the limit value. This can be done as monthly or yearly averages. Monitoring and surveillance Monitoring programmes should include both chemical and biological aspects so that where possible measured biological responses can be related to specific chemical exposures. The success of chemical monitoring depends on the implementation of a strong quality assurance programme. This is particularly true when several laboratories are involved. There are two basic components of a quality assurance programme. The first, quality control, includes activities designed to ensure that the sampling and analytical techniques are adequate for the intended purpose. This forms the basis 438
for deciding if a chemical monitoring programme is adequate to significantly detect predicted changes. The second component, quality assessment, provides an ongoing basis by which quality of data is maintained at the required level. This is accomplished through the use of standardized procedures, analysis of reference materials (certified and in-house) and interlaboratory comparisons. Chemical monitoring should not simply record total concentrations of substances but try to assess the bioavailable fraction. Recent advances in metal speciation studies (Lander, 1989) have considerably improved our knowledge of which metal species are bioavailable. For example by means of sampling and analysis of fish bile it is possible to assess the exposure of fish to chemicals with a medium water solubility, such as resin acids, chlorinated phenolics, vanillins etc., since such chemicals have a low tendency to accumulate in the lipid tissues of fish. If the results of the monitoring programme show that the agreed limits have been exceeded then the feed-back loop to the discharge limit should be enacted. It is essential in this strategy that the course of action in respect to the discharge limits is agreed in advance of discharge occurring. Too often in the past, there has been dispute as to whether or not discharge concessions have been broken as the limits were either not defined or not detectable with the monitoring programme. Alternatively there was no agreed course of action if limits were exceeded so that protracted litigation resulted during which time the environment was damaged. With the suggested strategy of setting clear limits based on hazard assessment predictions and on an a priori agreed course of action, if the limits are exceeded, better protection of the environment should result. It follows from the foregoing that the presence of a substance which has been subjected to a hazard assessment and the inputs of which are being effectively controlled according to sound scientifically based marine environmental protection strategies does not constitute cause for concern. The same cannot necessarily be said for substances that have not been subjected to such assessments. Not all chemicals discharged to the marine enviroment have been subjected to screening techniques such as those suggested above. For some, the QSAR approach would not have predicted severe environmental effects (e.g. tributyl tin). There is, therefore, need for programmes of surveillance to be set up to ensure that harmful effects are discovered. Thus, where a substance is unexpectedly detected or is found to be present at concentrations clearly above those that can be considered normal this should be considered as a warning signal. Accordingly, an assessment should be conducted of the sources and potential impact with a view to introduction of environmental management and protection measures if necessary. Surveillance differs from monitoring in that predictions are not tested but target sites or organisms are surveyed to ascertain whether or not there are detectable differences between the surveyed site and control sites. If a significant difference is observed then a response or feed-back loop should be initiated. In such cases there
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are different loops dependent on whether chemical or biological changes are recorded. If a significant difference in concentration of a chemical is found then a search is made for biological effects. There are a number of newly developed and effective biological effects monitoring techniques (see Bayne et al., 1988), which can be routinely applied to detect such biological effects. If no biological effects are found the sources, distribution and load should be investigated and routinely monitored for the chemical. If biological effects are found then the likely chemical initiating the response should be studied, (some biological effects techniques are specific to certain chemical stressors e.g. metallothionein induction) and the feed-back loop to sources, distribution and loads of the chemical found. Discharge limits should then be reexamined and new lower levels of discharge imposed. Thus monitoring and surveillance are important parts of the strategy but in the context of feed-back loops initiating a priori agreed sequences of action. Figure 2 shows diagrammatically how surveillance is perceived.
Conclusions and Recommendations The need for improving environmental protection on local, regional and global scales requires management strategies that take account of all alternatives and options for waste disposal (e.g. land, air and sea), and therefore the marine environment must not be considered in isolation from all others. However, having evaluated the currently applied approaches it is clear
that new strategies for purely marine environmental protection and management must also be developed. The new strategies should integrate relevant aspects of past approaches (toxicity, bioaccumulation, persistence), improved understanding of biogeochemical cycles, mass balance and other factors related to potential exposure. There is an important role to be played by holistic marine ecosystems modelling in marine environmental impact assessment. Most attempts to date have been oversimplistic in neglecting important processes such as sedimentation rates and associated chemical scavenging and cannot be reliably used for diagnostic purposes (models of this type can never sensuo stricto be truly predictive). Emphasis should be placed on a truly holistic approach where important physical, chemical and biogeochemical processes are \,integrated in such models. A model of this type is being developed for the North Sea as part of the work of the North Sea Task Force. Based on recent advances in various fields of science, described in this paper, we are of the opinion that it is now possible to develop comprehensive strategies for marine environmental protection and management. The basic components of such strategies have been briefly outlined in the present paper.
The authors wish to thank their sponsoring agencies, FAO, UN, Unesco/ IOC, UNEP, WMO for funding the working group and in particular FAO for its secretariat function.
SURVEILLANCE Compare sites/organisms with control
CHEMICAL Present at concentrations higher than control?
[ Is there an effect on the biological system?
l
BIOLOGICAL Are there changes in effects on biological systems?
[Identify cause ]
Proceed to HAZARD ASSESSMENT Fig. 2 An integrated approach for the study of marine pollution. Strategy for investigations indicating the path for haza~ assessment.
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Marine Pollution Bulletin Alabaster, J. & Lloyd, R. (1982). Water Quality Criteria for Freshwater Fish. Butterworths, London. Anon. (1986). Umweltpolifik:Guidelines on anticipatory environmental protection. Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. Anon. (1990). This Common Inheritance. Britain's Environmental Strategy. HMSO. Bacci, E., Calamari, D., Gaggi, C. & Vighi, M. (1989). Bioconcentration of organic chemical vapours in plant leaves: experimental measurements and predictions. Env. Sci. Technol. Baudo, R., Giesy, J. & Mantau, H. (1990). Sediments: Chemistry and Toxicity ofln Place Pollutants. Lewis Pub. Inc. Ann. Arbor. Bayne, B. L., Clarke, K. L. & Gray, J. S. (1988). Biological effects of pollutants: Results of a practical workshop. Mar. Ecol. Progr. Ser. 46, 1-278. Bewers, J. M. (1989). Marine Environmental protection initiatives in europe: Steps to emulate and steps to avoid. Proceedings of the Gulf of Maine Conference, December, 1989. (In press). Bidleman, T. E. (1988). Atmospheric processes. Wet and dry deposition of organic compounds are controlled by their vapor-particle partitioning. Env. Sci. Technol. 22, 361-367. Blaise, C., Sergy, G., Wells, P., Bermingham, N. & Van Collie (1988). Biological testing-development, application and trends in Canadian EnvironmentalProtection Laboratories. Tox. Assess. 3, 385-406. Buat-Menard, P. (1986). The Role of Air-Sea Exchange in Geochemical Cycling. NATO-ASI Series, 185 Reidel, Boston. Cairns, J. Jr. (1977). Aquatic ecosystem assimilative capacity. Fisheries 2, 1-4. Cairns, J. Jr., Dickson, K. L. & Maki, A. W. (1978). Summary and conclusions. In Estimating the Hazard of Chemical Substances to Aquatic Life. ASTM STP 657. (J. Cairns Jr., K. L. Dickson & A. W. Maki, eds), pp. 191-197. ASTM, Philadelphia. Calamari, D. & Vighi, M. (1989). Quantitative structure activity relationships in ecotoxicology. Re~. Env. Toxicol. 4. Calamari, D. & Vighi, M. (1990). The role of ecotoxicology in environmental protection. In Basic Science ~in Toxicology (G. N. Volans, J. Sims, E M. Sullivan & E Turner, eds), pp. 193-205. Taylor & Francis, London. Clark, R. B. (1982). The impact of oil pollution on marine populations, communities and ecosystems: a summing up. Phil. Trans. Roy. Soc. Lond. B. 297,433-443. Cttt, R. E (1989). The many dimensions of marine environmental quality. Discussion paper. Science, Council of Canada, Ottawa. C6tt, R. E, Vanderzwaag, D. & Townsend Gault, I. (1988). Social, economic, institutional and legal considerations in the management of land-based sources of marine pollution. In Proceedings of the Canadian Conference on Marine Environmental Quality. (P. G. Wells & G. Gratwick, eds), pp. 59-74. The International Institute for Transportation and Ocean Policy Studies, Halifax, N.S., Canada. GESAMP, (1986). Environmental capacity. An approach to marine pollution prevention. Reports and Studies GESAMP, 30. GESAMP, (1990). Interchange of pollutants between the atmosphere and the oceans. Reports and Studies. Gray, J. S. (1990). Statistics and the Precautionary Principle. Mar. Pollut. Bull. 21, 174-176.
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Hermens, J. (1989). Quantitative structure activity for environmental pollutants. In Handbook of environmental chemicals (O. Hutzinger, ed.), pp. • Springer-Verlag, Berlin. Hutzinger, O. (lEd.) (1982). Handbook of Environmental Chemicals, Vol. 2, Part A. Reactions and Processes. Springer Verlag, Berlin. Hutzinger, O. (lEd.) (1982). Handbook of Environmental Chemicals, Vol. 2, Part B. Reactions and Processes. Springer-Verlag, Berlin. Karickoff, S. W., Brown, D. S. & Scott, T. A. (1979). Sorption of hydrophobic pollutants on natural sediments. Water Res. 13, 241-248. Lander, L. (1988). Hazardous chemicals in the environment. Some new approaches to advanced assessment. Ambio 17, 360-366. Lander, L. (Ed.) (1989) Speciation of Metals in Water, Sediment and Soil Systems. Springer-Verlag, Berlin. Lander, L. (Ed.) (1989). Chemicals in the Aquatic Environment. Advanced Hazard Assessment. Springer-Verlag, Berlin. Mackay, D., Paterson, S. & Schroeder, W. H. (1986). Model describing the rates of transfer processes of organic chemicals between atmosphere and water. Env. Sci. Technol. 20, 810-816. North Sea Conference (1987). Ministerial Declaration. Her Majesty's Stationery Office, London, April 1988. OECD (1986). Existing Chemicals Systematic Investigation. OECD, Paris. Rao, E C. S., Hornsby, A. G. & Jessup, R. E. (1985). Indices for ranking the potential for pesticide contamination of groundwater. Soil Crop Sci. Soc. 44, 1-8. Reckhow, K. H. & Chapra, S. C. (1983). Engineering Applications for Lake Management, Vol. 1. Data analysis and empirical modelling. Butterworth, London. Tateya, S., Tanake, S. & Tasukawa, R. (1988). PCB on the globe: Possible trend of future levels in the open ocean environment. In Toxic Contamination in Large Lakes (N. W. Schmidke, ed.), pp. 237-281. Lewis Pub. Inc., Ann Arbor. UNEP. (1985). Protection of the marine environment against pollution from land-based sources. Montreal Guidelines. Environmental Policy and Law, 14/2/3: 77-83. Veith, G. D., De Foe, D. L. & Bergsted, B. V. (1979). Measuring and estimating the bioconcentrationfactor in fish. J. Fish Res. Bd. Can. 36, 1040-1046. Vighi, M. & Bacci, E. (1989). The Mediterranean sea-environmental impact of chemicals. In First European Conference on Ecotoxicology (H. l_~kke & E Bro Rasmussen, eds). The Technical University of Denmark, Lyngby. Vollenwieder, R. A. (1975). Input-output models with special reference to the phosphorus loading concept in linmology. Scweizerische Zeitschri~ fiir Hydrologic. 37, 1040-1046. Wells, P. G. & Cott, R. P. (1988). Protecting marine environmental quality from land-based sources of pollutants. The strategic role of ecotoxicology. Mar. Pol. 12, 9-21. Wells, G. P. & Gratwick, J. (Eds.). (1988). Proceedings of the Canadian Conference on Marine Environmental Quality, The International Institute for Transportation and Ocean Policy Studies, Halifax, N.S., Canada. World Commission on Environment and Development (1987). Our Common Future. Oxford University Press, Oxford.
0025-326X/91 $3.00+0.00 O 1991 Pergamon Press plc
Viewpoint is a column which allows authors to express their own opinions about current events.
Scientifically Based Strategies for Marine Environmental Protection and Management JOHN S. GRAY*, D. CALAMARI, R. DUCE, J. E. PORTMANN, P. G. WELLS and H. L. WINDOM
The authors are all members of the UN Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP). This paper is the result of a GESAMP Working Group.
During the last decades, mankind has faced a wide range of environmental degradations: changes in climatic conditions and biogeochemical cycles, a number of ecoaccidents, the appearance of xenobiotics in remote areas and a general world-wide deterioration in environmental quality. The results in the aquatic environment were dramatic with effects such as massive fish kills and large areas of sea bed devoid of oxygen. Measures taken to protect the aquatic environment from such effects thus far have been based on strategies such as the Water Quality Standards, Black and Grey Lists and the Precautionary Principle. Recently, the so-called Brundtland report (World Commission on Environment and Development, 1987) postulated that a state of sustainable development was the ultimate goal to be reached by development and environment protection measures. The following are among the principles and responsibilities proposed by the Commission: • Conservation and Sustainable Use: States shall maintain ecosystems and ecological processes essential to the functioning of the biosphere, shall preserve biological diversity, and shall observe the principle of optimum sustainable yield in the use of living natural resources and ecosystems. • Environmental Standards and Monitoring: States shall establish adequate environmental protection standards and monitor changes in and publish relevant data on environmental quality and resource use. • Prior Environmental Assessments: States shall make *To whom correspondence should be addressed at Department of Marine Zoology, University of Oslo, P.O. Box 1064, 0316 Blindern, Oslo 3, Norway.
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or require prior environmental assessments of proposed activities which may significantly affect the environment or use of a natural resource. These new tasks and challenges, as well as new developments in science, make it necessary to re-consider existing strategies for the protection of the marine environment, and to propose new ones. It is, however, clear that in view of a number of global changes in the environment, e.g. climatic changes, measures to protect the marine environment cannot be taken in isolation but will also have to take into account other environmental compartments, e.g. land and air. As a first response to these challenges, this paper attempts to analyse current marine environmental protection strategies, identifying both their drawbacks and limitations and those elements of the scientific principles and management approaches that could be combined to provide a more comprehensive and effective framework for the protection of the marine environment, including its resources and amenities. The paper also provides an outline of such an overall framework that would provide an opportunity for the application of developments in scientific understanding to marine environmental protection and management.
Analysis o f existing aquatic environmental protection and m a n a g e m e n t strategies
Water Quality Standards Probably the earliest approach to environmental protection and management of aquatic systems involved the use of water quality standards or criteria. These continue to be widely used. However, many of these
Volume22/Number9/September1991 standards were first established decades ago, albeit on a scientific basis considered to be the best at the time (Alabaster & Lloyd, 1982). AS a result of the use of water quality standards in environmental management, most monitoring and surveillance programmes in aquatic systems have focused on the analysis of the concentration of potentially harmful substances in the water column. Because it is often not in the water column where the impact occurs, these programmes often lead to misperceptions of the problem or, even worse, failure to notice a problem until it is quite serious. Experience in the analysis of potentially harmful substances in the water column has shown that this is often difficult to perform precisely and accurately. As a consequence, past results of monitoring programmes, especially those involving several laboratories, have often either failed to detect changes when they have occurred or have indicated that water quality standards have been exceeded when they have not. These analytical difficulties have been generally overcome in developed countries by the introduction of new techniques and instruments, and by the implementation of quality assurance programmes. In developing countries, however, such improvements have not generally occurred, although many of these countries in principle use water quality standards in their aquatic environmental protection and management programmes. Existing water quality standards are mainly based on short-term bioassays of acute or lethal effects on test organisms that reside in the water column. The implied assumption is that the major compartment of the aquatic system in which the substance will accumulate, or at least have its impact, is the water column. The use of water quality standards usually does not take into account which species is the most sensitive to the substance. Furthermore, their use does not allow for the major impact that might arise due to the accumulation of the substance in one species which, although itself is unaffected, is fed upon another (e.g. man) which is affected. Another criticism of the past and present use of water quality standards in aquatic environmental protection and monitoring is that they are often applied ubiquitously to drastically different systems (e.g. freshwater and marine). This clearly does not take into consideration biogeochemical and ecological differences in aquatic systems, nor does it take into account the impact of multiple sources, i.e. overall load, nor does it take into account the impact of the substances in the areas of medium and long-term residence. In the past few years, however, considerably more has been learned about the biogeochemical behaviour of potentially harmful substances in aquatic systems and their toxicity to aquatic organisms. Current understanding of the biogeochemical behaviour of many potentially harmful substances (e.g. heavy metals, synthetic organics), however, indicates that they accumulate primarily in aquatic sediments. Thus there has been a change of emphasis way from simply defining water quality criteria to setting criteria for sediments (e.g. Baudo et al., 1990).
Black and Grey Lists The black and grey list approach divides substances into two groups. The first consists of substances that are regarded as so dangerous that they should not be allowed to enter the aquatic environment. The second group is considered less dangerous and such substances can be allowed to enter the aquatic environment, subject to certain precautions. The first group was intended to consist of substances that are highly persistent, highly toxic to one or more groups of organisms and strongly bioaccumulatable. The second group was expected to be characterized by low persistence, low toxicity and low bioaccumulation potential. Application of the concept has proved difficult for two main reasons: firstly, there is no clear dividing line between the groups. Secondly, when the lists were drawn up, substances were grouped together in one or other list according to the worst characteristics of some members of the group, however atypical of the whole group. It is now clear that the concept of two lists is in any event seriously flawed because the degree or persistence depends on environmental conditions which affect the behaviour of the substance .and the significance of both toxicity and bioaccumulation differs according to the target organisms. Thus, if status on a list is the sole criterion for decision-making, local conditions and biogeochemical behaviour a r e not taken into account. Furthermore, in its application little or no attention was paid to sources of the substances other than those involving direct discharge to the marine environment or to the cumulative effect of different sources at a local, regional or global level. Another weakness of the black and grey list approach is that they do not include the vast majority of organochlorines and other organics that are poorly or not described and yet are being discharged daily in industrial effluents. The black and grey list does not include chemicals that are released as complex mixtures, unless such mixtures are identified as a class of substances to be considered separately and controlled (e.g. organochlorine compounds in bleachery effluents). For these reasons, the black and grey list approach cannot be considered to be a properly developed scientifically based environmental management and protections system because it ignores particular circumstances that influence the risk the substances actually pose in a real situation. Nevertheless, the underlying idea that persistence, bioaccumulation and toxicity are important indicators of the likely hazard posed by a substance is scientifically sound.
The Precautionary Principle At the Second North Sea Conference, a new approach to environmental protection was adopted by acceptance of the precautionary principle (North Sea Conference, 1987). The precautionary principle is based on an earlier German initiative (Anon. 1986) but is a much simplified version of the original, which was a scientifically sound and logical document, (see Bewers (1989) for a review). The precautionary principle applies to substances that are persistent, toxic or bioaccumulatable but, in a highly significant departure from previous 433
Marine PollutionBulletin approaches, states that precautionary action should be taken, even without scientific evidence of cause and effect relationships, if the substance is suspected of having detrimental effects on the marine environment. In scientific terms, acceptance of this principle, especially defined in the terms used above, poses a number of fundamental problems (Gray, 1990). Firstly, the terms persistent, toxic and bioaccumulatable are not defined. At its most extreme all elements should be banned from discharge since they are persistent. Likewise, does toxic mean toxic to all marine species, and at what concentration or dose is a substance defined as 'toxic', as all chemicals will become toxic at sufficiently high levels? Some chemicals bioaccumulate naturally and yet pose no stress symptoms in the accumulating organism nor do they present health risks for other species consuming them. It is obvious that there is a strong case for both qualitative and quantitative definitions of these terms that will allow proper management of the marine environment and yet maintain the spirit of the precautionary principle. A second major criticism of the precautionary principle is the acceptance of suspicion of effects rather the scientific evidence as sufficient to introduce discharge controls. Providing that there are sufficient data available to make a thorough Hazard Assessment (see below) and providing that a sound monitoring strategy is in operation to test the predictions made, then only objective scientific evidence should be used for environmental protection and management purposes. As it stands, the precautionary principle can be invoked by simply arguing that at some future date a given chemical is likely to have an effect and discharge to sea therefore should be banned. Since the introduction of most substances to the marine environment will cause at least local disturbances and because effect is not defined, this argument can and is being invoked in relation to most sources of direct inputs to the marine environment. With a sound monitoring programme and with agreed limits for the discharge there should be little or no danger to the environment resulting from using only objective scientific criteria to judge whether or not limits have been exceeded. The precautionary principle does, however, have a role to play in cases where little is known about the chemical concerned or where the biogeochemical cycle and risks for the chemical in the environment are so poorly understood that a reasonably complete hazard assessment cannot be made and the critical load and monitoring targets cannot be identified. The precautionary principle has a further role in the introduction of environmental management in that it would argue against discharges where concentrations are approaching environmental quality standards and/or critical loads at all times and particularly in the early stages prior to the accuracy and predictions being proven.
Best Available Technology Whilst it may seem logical that one should employ the best available technology to minimize discharges of toxic 434
chemicals in order to protect the environment, there are problems with adopting this approach. In some circumstances the use of the best available technology may prove to be overprotective (e.g. a small discharge of a substance with limited persistence and toxicity made to a large receiving environment) or alternatively in other situations it may prove to be totally inadequate (e.g. discharge of a highly persistent and toxic substance made in large quantity to a small receiving environment or in smaller amounts but from several different sources to the same area). Whether or not the adoption of the best available technology should include an assessment of economic costs and/or the consequences for other environmental sectors is a controversial and much debated point. For example, Britain argues strongly for using the best available technology which does not entail excessive economic costs (BATNEEC), (see p. 138 of Anon. 1990). The use of the best available technology does, however, have a role to play in a fully developed environmental management and protection strategy, provided that comparison is made to the available alternatives and proper costings are done. This is because sound environmental management principles would advocate that inputs to the marine environment be kept as low as practicable, due account being taken of the consequences for other sectors of the environment.
The Montreal Guidelines The Montreal guidelines (UNEE 1985) are a set of recommendations to governments to assist them in development of legislation for the protection of the marine environment against pollution from land-based sources. The guidelines have taken common elements and principles from existing agreements such as the Oslo, Paris and Helsinki Conventions, the Athens protocol and the U N convention on the Law of the Sea. In annex 1 to the guidelines a section on strategies for protecting, preserving and enhancing the quality of the marine environment is presented. Firstly, there are control strategies such as those based on marine quality standards, emission standards and environmental planning. The marine quality guidelines consider standards based on water, sediment, fish or their tissues, health or community composition, but do not give a framework for deciding how the set of standards should be derived. It is suggested that no change over ambient concentration of a given substance should be used, but this does not take into account the fact that a given ambient concentration may not have any deleterious effects. Dilution and loads are also mentioned, but other important components of hazard assessment are not considered (see below). Under emission standards, technology standards are considered, and it is suggested that these should be applied on a sector by sector basis. A distinction is drawn between best practicable technology which takes into account costs and best available technology which does not, but which it is suggested should apply to the most noxious substances. Under planning strategies the guidelines recommend
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that certain activities are incompatible with the particular values or uses of the environment; that uses of the environment will have different quality standards and the standards should be defined for the specific uses; that environmental impact assessments are necessary for any activity affecting the environment; that regional management is needed for such areas as the coastal zone, drainage basins and specially sensitive areas. Thus, the guidelines give a useful checklist of factors that have to be considered but they do not provide a logical scientific framework for protection and management of the marine environment. It is this framework that will be developed in the following section.
Towards an integrated strategy The overall conclusions of this analysis indicate that an integrated framework for environmental protection and management is called for, (see also Calamari & Vighi, 1990). The fundamental idea that persistence, toxicity and bioaccumulation potential are key indicators of the potential hazard posed by a substance to the marine environment is scientifically sound. The same can be said of the concept of environmental capacity or critical environmental loads. What the currently adopted environmental protection strategies fail to provide for are variations in local circumstances and the biogeochemical behaviour of the substance once it is released into the environment. It is now clear that the latter, in particular, plays a vital role in determining both the actual impact of the substance and where that impact occurs.
precludes anything other than local scale effects still merit implementation of proper environmental management strategies. However, by the very nature of their effects, in most cases recovery of impacted environments will usually be rapid, e.g. within a few years in the case of most oil spills (Clark, 1982), as recolonization occurs from the surrounding unaffected area. During the seventies, when a shift from control to prevention took place, it was realized that control of conventional pollutants alone was an inadequate strategy. Three additional reasons emphasize the need for a different strategy in pollution control: 1. the need to protect the whole environment and not just one of the compartments (water, air, land) or a single identified target species; 2. the huge quantity of information necessary to formulate quality criteria for any environmental compartment, and 3. the great number of chemical substances actually used by man as well as the variety of chemical groups to which these substances belong, (OECD, 1986). It is clear from the preceding discussion that many of the old approaches to marine environmental protection and management must be augmented by new ones which taken into account our improved understanding of natural aquatic systems. The following sections describe several essential components of an integrated framework for the protection and management of the marine environment that integrate new scientific developments with past experience. Figure 1 shows a diagrammatic outline of the new strategy which is directed towards the prediction of impacts of chemicals in the marine environment.
Thus, whilst problems may be caused at a local level by excess inputs of virtually any chemical substance, the Hazard Assessment extent to which they occur at a regional level depends At the conclusion of a symposium of the American upon the degree to which a chemical remains in the Society for Testing and Materials on Estimating the water column or is transported away from the source of Hazard of Chemical Substances to Aquatic Life, Cairns et input via sediment mobilization mechanisms. Examples al. (1978) stated that: "a hazard assessment to measure of such problem-causing substances are certain metals, the risk must ultimately be based upon sound scientific nutrients and oils. A few substances, through their judgement applied to knowledge of expected environextreme volatility or persistence, may be capable of mental concentration of the material and the material's causing effects on a global scale even though the source toxicological properties". This simple concept highlights of their introduction is limited to particular areas. the importance of exposure and the fact that a toxicoExamples of such substances and problems are PCBs, logical criterion is only part of the pollution control the greenhouse gases and acid rain. Chemicals that have strategy. Furthermore, it highlights the difference a potential to cause effects on a regional scale also merit between the hazard potential of a substance and the early attention since recovery of the environment on a actual risk of a problem being caused as a consequence regional scale is likely to take years and will usually of exposure to the hazard. involve development of mechanisms for coordinating In the last ten years, the capability for environmental action on a multi-national level. management of chemicals has greatly increased due to The substances most urgently meriting control are the the availability of conceptual approaches and technical latter group, since by the very scale of their potential tools developed by the scientific community. The two effects control will be difficult and recovery slow. One of most relevant conceptual frameworks, not yet fully the difficulties to be faced is likely to be a conflict of explored and exploited, are the assimilative capacity, interest between the developed and developing nations. which is defined as "the ability of a receiving system or The former group are most likely to seek desired ecosystem to cope with certain concentrations or levels environmental improvements whereas the latter group of waste discharges without suffering any significant may attach more importance to the benefit, in the deleterious effects" and the hazard assessment approach economic, agricultural or human health protection (previously defined) both orginally proposed by Cairns terms, provided by continued use and release of the 1977) and Cairns et al. (1978). These two approaches chemical. have been successively developed by several authors; Those chemicals whose biogeochemical behaviour see for example in relation to assimilative capacity the 435
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[ PRODUCTION, USES, DISCHARGE PAqTERNS, LOADS, SOURCES I PHYSICO-CHEMICAL ~ . . , ~ PROPERTIES
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ASSESSMENT I OF LIKELY EFFECTS
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Fig. 1 An integrated approach for the study of marine pollution (The hazard assessment procedure).
GESAMP report on Environmental capacity. An approach to marine pollution prevention (GESAMP, 1986) and for hazard assessment the Scandinavian experience extensively described by Lander (1988). It should be noted that far from seeking to use the environments' resilience to the full, the environmental capacity approach in effect seeks, first to define the critical load; then, in its application seeks, not just to avoid exceeding the defined limits, but to keep actual inputs as far as practicable below this. Any kind of evaluation for a potentially harmful chemical substance must taken into account two types of factors, the first intrinsic with the substance, the second 436
related to the extrinsic conditions and their reciprocal interactions (Wells & Cot6, 1988; Vighi & Bacci, 1989). Basically, the necessary parameters belong to seven classes: • quantity: production, uses, discharge patterns, loads, sources; • distribution: physico-chemical characteristics, affinity for environmental compartments, sinks; • persistence: kinetics of hydrolysis, photolysis, biodegradation; • bioaccumulation: n-octanol/water partition coefficient, metabolic pathways in different organisms;
Volume22/Number9/September1991 • toxicity: measures of biological activity of the substance (ideally from cells to ecosystems); • ecosystem typologies: biotic and abiotic characteristics and structure and functions of ecosystems. • targets of exposure: considerations about the vulnerability and stability of (a) potential target communities and (b) life cycle stages of potential target species. Obviously consideration must also be given to the time scale of the events. Up to now, great importance has only been attributed to three of these parameters (toxicity, bioaccumulation, persistence) e.g. the North Sea Declaration (1987) and although limited attention has recently been given to the loads (particularly from land-based sources) these have rarely been correctly quantified. The seven classes listed above incorporate many new research findings concerning physico-chemical and biological properties, mass balance models, etc. Physico-chemical Properties There is growing recognition of the importance of atmospheric inputs of chemicals to the marine environment. Recent calculations reveal that global input from the atmosphere dominates riverine input for the metals lead, cadmium and zinc as well as for most high molecular weight chlorinated hydrocarbons, whereas atmospheric and riverine inputs are similar for copper, nickel, arsenic, iron, nitrogen and phosphorus (GESAMP, 1990). There have been marked improvements in the laboratory determination of Henry's Law Constants and gas exchange coefficients necessary to model the air/sea exchange of gaseous pollutants, (Mackay et al. 1986; Bidleman, 1988; Buat-Menard, 1986). Through knowledge of the kinetics of hydrolysis, photolysis and data on biodegradation rates of chemicals it is possible to predict their persistence in the environment (Hutzinger, 1982 a,b). Likewise the soil sorption partition coefficient can provide substantial information on physical movements of hydrophobic chemicals (Karichoff et al., 1979) and have been used to rank chemicals for ground water contamination (Rao et al., 1985) and should have relevance in the marine environment. Studies of biogeochemical cycles of estuarine and continental shelf systems during the past two decades have greatly increased our understanding of how processes within these systems affect the fate and flux of contaminants delivered to the marine environment. If one assumes that these systems along with continental slopes constitute the ocean margin, it has been estimated that more than 95% of the nitrogen delivered by rivers accumulates in this region. Thus, increased mobilization of nitrogen on land may have major impacts in ocean margins. Yet the processes are complex in some areas. Although nitrate levels have increased in rivers the same has not occurred in coastal areas due to biological removal and loss by denitrification and ammonia production. Because of the particle reactivity of most pollutants, the ocean margin, not the deep ocean, is the ultimate sink for most river-transported contaminants. In fact,
recent evidence suggests that ocean margins may als0 be a major sink for materials from the open ocean. For example, plutonium, which is delivered to the ocean primarily through the atmosphere, accumulates disproportionately in ocean margins. Lead and other anthropogenically mobilized substances, primarily transported by the atmosphere, may behave similarly. Having obtained data on quantities of material discharged, on physico-chemical properties, and on the environment one can proceed to an evaluative model. The role of mass-balance models and other components The next phase is the construction of a mass balance model since this will serve to confirm that all sources and sinks have been accounted for. One of the most effective and simplest of these has been the VoUenweider model for treatment of lake eutrophication (Vollenweider, 1975, and more recent modifications Reckhow & Chapman, 1983). The model has been successfully applied in many different geographical areas. Yet in some cases the model predictions have not been borne out. It is now realized that different biological structures in lake ecosystems have important consequences for phosphorus cycling. Thus, to obtain more exact management tools it is necessary to understand phosphorus cycling under systems with different biological structures. There are few other models that have been as successful as the Vollenweider model. One goal of future research, therefore, should be to find other models which can be used in a marine context, (see e.g. Tateya et aL, 1988). There is an urgent need for models for nitrogen and phosphorus in relation to marine eutrophication problems but it is unlikely that the simplicity of the Vollenweider approach can be as successful in the complexity of the marine environment. Biological properties The prediction of effects has been made possible by means of studies on quantitative structure activity relationships (QSAR) in ecotoxicology, (Calamari & Vighi, 1989; Hermens, 1989). QSARs have been developed for several classes of chemicals and allow within these classes, good estimates of the toxicity of chemicals. However, QSARs have been applied to a limited number of chemicals and some expert judgement is still required to determine the boundaries of toxicological predictability when using the QSAR approach. Nevertheless if experimental toxicological data are unavailable, QSARs can be applied within heterogeneous groups of chemicals and do offer a basis for some predictability, certainly in respect to selecting priority substances. Toxicity testing has also advanced greatly in recent years with development of new and more standardized tests (Blaise et al., 1988). The n-octanol/water partition coefficient has been demonstrated to be a useful parameter to predict the potential for bioaccumulation of chemical substances in several organisms (Veith et al., 1979; Bacci et al., 1989) and should be further studied in marine organisms. Advances in biological effects monitoring techniques 437
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using, for example, physiological techniques such as 'scope for growth' of bivalve mussels, mixed function oxygenase (MFO) enzyme systems in fish, metallothionein detoxification systems in fish and new multivariate analysis techniques for benthic communities have been shown to distinguish fine gradients of pollution effects that were not detectable a decade ago (Bayne et aL, 1988).
Prediction of impacts The hazard assessment process should yield clear predictions of: • the transport pathways and rates, • the likely environmental compartment (water, sediment and/or biota) where the substance/material is likely to accumulate, • the chemical composition and concentration of the substance, and • the likely impact of the substance/material at a given target site or on a given organism or set of organisms. For example, one could predict from its biogeochemical characteristics that the concentration of a chemical is not likely to increase in a given compartment by more than a certain percentage over background levels (it is assumed that the given percentage increase over background is detectable by the sampling and analysis procedures available and would not induce detrimental effects on biological system). The background levels together with natural sampling and analysis variability would be given. Any statistically significant increase by more than the given percentage over background would trigger a feedback loop on the discharge concession. Predictions should not only be made of chemical concentrations but also of any expected biological effects. Clearly stated limits to changes in either a stress response of a given species and/or a community response should be made. If statistically significant changes over the prediction are found then again this should trigger the feed-back loop on the discharge concession with the questions: are the effects observed acceptable or why were they not predicted? Such a priori predictions require that monitoring is done with the best available techniques and is targeted specifically at sites and/or organisms that can be expected to show effects. In setting discharge limits it is important to specify statistical limits above which a given fraction of samples is allowed to exceed the limit value. This can be done as monthly or yearly averages. Monitoring and surveillance Monitoring programmes should include both chemical and biological aspects so that where possible measured biological responses can be related to specific chemical exposures. The success of chemical monitoring depends on the implementation of a strong quality assurance programme. This is particularly true when several laboratories are involved. There are two basic components of a quality assurance programme. The first, quality control, includes activities designed to ensure that the sampling and analytical techniques are adequate for the intended purpose. This forms the basis 438
for deciding if a chemical monitoring programme is adequate to significantly detect predicted changes. The second component, quality assessment, provides an ongoing basis by which quality of data is maintained at the required level. This is accomplished through the use of standardized procedures, analysis of reference materials (certified and in-house) and interlaboratory comparisons. Chemical monitoring should not simply record total concentrations of substances but try to assess the bioavailable fraction. Recent advances in metal speciation studies (Lander, 1989) have considerably improved our knowledge of which metal species are bioavailable. For example by means of sampling and analysis of fish bile it is possible to assess the exposure of fish to chemicals with a medium water solubility, such as resin acids, chlorinated phenolics, vanillins etc., since such chemicals have a low tendency to accumulate in the lipid tissues of fish. If the results of the monitoring programme show that the agreed limits have been exceeded then the feed-back loop to the discharge limit should be enacted. It is essential in this strategy that the course of action in respect to the discharge limits is agreed in advance of discharge occurring. Too often in the past, there has been dispute as to whether or not discharge concessions have been broken as the limits were either not defined or not detectable with the monitoring programme. Alternatively there was no agreed course of action if limits were exceeded so that protracted litigation resulted during which time the environment was damaged. With the suggested strategy of setting clear limits based on hazard assessment predictions and on an a priori agreed course of action, if the limits are exceeded, better protection of the environment should result. It follows from the foregoing that the presence of a substance which has been subjected to a hazard assessment and the inputs of which are being effectively controlled according to sound scientifically based marine environmental protection strategies does not constitute cause for concern. The same cannot necessarily be said for substances that have not been subjected to such assessments. Not all chemicals discharged to the marine enviroment have been subjected to screening techniques such as those suggested above. For some, the QSAR approach would not have predicted severe environmental effects (e.g. tributyl tin). There is, therefore, need for programmes of surveillance to be set up to ensure that harmful effects are discovered. Thus, where a substance is unexpectedly detected or is found to be present at concentrations clearly above those that can be considered normal this should be considered as a warning signal. Accordingly, an assessment should be conducted of the sources and potential impact with a view to introduction of environmental management and protection measures if necessary. Surveillance differs from monitoring in that predictions are not tested but target sites or organisms are surveyed to ascertain whether or not there are detectable differences between the surveyed site and control sites. If a significant difference is observed then a response or feed-back loop should be initiated. In such cases there
Volume 22/Number 9/September 1991
are different loops dependent on whether chemical or biological changes are recorded. If a significant difference in concentration of a chemical is found then a search is made for biological effects. There are a number of newly developed and effective biological effects monitoring techniques (see Bayne et al., 1988), which can be routinely applied to detect such biological effects. If no biological effects are found the sources, distribution and load should be investigated and routinely monitored for the chemical. If biological effects are found then the likely chemical initiating the response should be studied, (some biological effects techniques are specific to certain chemical stressors e.g. metallothionein induction) and the feed-back loop to sources, distribution and loads of the chemical found. Discharge limits should then be reexamined and new lower levels of discharge imposed. Thus monitoring and surveillance are important parts of the strategy but in the context of feed-back loops initiating a priori agreed sequences of action. Figure 2 shows diagrammatically how surveillance is perceived.
Conclusions and Recommendations The need for improving environmental protection on local, regional and global scales requires management strategies that take account of all alternatives and options for waste disposal (e.g. land, air and sea), and therefore the marine environment must not be considered in isolation from all others. However, having evaluated the currently applied approaches it is clear
that new strategies for purely marine environmental protection and management must also be developed. The new strategies should integrate relevant aspects of past approaches (toxicity, bioaccumulation, persistence), improved understanding of biogeochemical cycles, mass balance and other factors related to potential exposure. There is an important role to be played by holistic marine ecosystems modelling in marine environmental impact assessment. Most attempts to date have been oversimplistic in neglecting important processes such as sedimentation rates and associated chemical scavenging and cannot be reliably used for diagnostic purposes (models of this type can never sensuo stricto be truly predictive). Emphasis should be placed on a truly holistic approach where important physical, chemical and biogeochemical processes are \,integrated in such models. A model of this type is being developed for the North Sea as part of the work of the North Sea Task Force. Based on recent advances in various fields of science, described in this paper, we are of the opinion that it is now possible to develop comprehensive strategies for marine environmental protection and management. The basic components of such strategies have been briefly outlined in the present paper.
The authors wish to thank their sponsoring agencies, FAO, UN, Unesco/ IOC, UNEP, WMO for funding the working group and in particular FAO for its secretariat function.
SURVEILLANCE Compare sites/organisms with control
CHEMICAL Present at concentrations higher than control?
[ Is there an effect on the biological system?
l
BIOLOGICAL Are there changes in effects on biological systems?
[Identify cause ]
Proceed to HAZARD ASSESSMENT Fig. 2 An integrated approach for the study of marine pollution. Strategy for investigations indicating the path for haza~ assessment.
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