Publication Abstract

Marine Pollution 1990

J.E. Portmann

The ICES Advisory Committee on Marine Pollution (ACMP) is responsible for the provision of advice to the ICES Council and, on behalf of Council, to outside organizations or to individual countries at their request. The ACMP produces a report each year in which it publishes its advice both on the various questions put to it and on topics it feels its audience will, or should, find of interest. The 1990 report was published late in September 1990 by ICES, in its Cooperative Research Report Series (No. 172) and is available from the Council's Offices in Copenhagen (2-4 Palaegade, Copenhagen K). This short article gives brief information on some but by no means all of the main topics covered in the 1990 report.

As with previous ACMP reports the range of topics covered in the 1990 report is substantial. Most of the text relates to issues raised by the pollution regulatory Commissions of the Helsinki, Oslo and Paris Conventions, either updating earlier advice or providing a detailed response to specific questions. As in previous years the ACMP has drawn heavily upon the expertise available through the ICES Working Group system and the 22 Sections of the report (and 10 Annexes) contain advice drawn from almost as many working groups.

One of the main pollution related activities undertaken in the last decade was the conduct of studies designed to establish the baseline level of contaminants in the North Atlantic and adjacent seas. A report on the 1985 Baseline study of contaminants in fish and shellfish, carried out jointly with the Oslo, Paris and Helsinki Commissions, was published in January 1988 (CRR No. 151). During the three year period, 1985, 1987, a similar study was conducted of the levels of trace metals in sea water. The results of the series of surveys were assessed during 1990 and a full report will be published later in 1991. Section 7 of the 1990 ACMP report describes how the results were assessed and gives a summary of the main findings, in relation to cadmium, copper, lead, mercury and zinc. The results show that the levels of all five metals are, outside the immediate influence of land run-off i.e. where salinity exceeds 30, remarkably uniform throughout the area studied. A gratifyingly large number of laboratories are now clearly capable of producing good quality, reliable data on metals in sea water, but some clearly still need to improve their techniques. As with the contaminants in biota study, ACMP notes that several participants failed to follow the agreed protocols and stresses the importance of adhering to agreed procedures in any future studies.

The 1990 ACMP report also contains a summary of another more detailed report on contaminant levels to be published in 1991. This relates to contaminants in sediments in the Baltic Sea area and represents the culmination of a major review of available data, some of it not previously published. In the light of the review it is recommended that a coordinated study be carried out in 1993 and, that to ensure comparable data, all the work should be carried out from a single research vessel using identical sampling, storage and analytical methods.

In response to a question raised by the Helsinki Commission, and recognizing the considerable concerns expressed by the popular press and North Sea Ministers, Section 12 of the report addresses the question of algal blooms and their causes. The report points out that algae bloom and die in the natural course of events and that really what causes concern is the unusual or exceptional event. Often these are not the result of blooms in the true scientific sense but, as with the case of the Chrysochromulina polylepis bloom in the Kattegat/Skagerrak in 1988, merely reflect an unusual aspect of a natural event-in that particular case normal occurrence, natural biomass but, unusually a toxin was formed. The ACMP warns that the continued input of unnaturally high quantities of nutrients to the marine environment is liable to stimulate growth of phytoplankton species generally, including those which are both toxic or noxious. Although, as is demonstrated by analogy to a terrestrial field, prediction of which species will become dominant is not yet entirely reliable there is reason for optimism in the sense that certain factors associated with problem bloom events are now clearly recognizable and predictable. Accordingly it should soon be possible to offer advice, with reasonable assurance of success, on what remedial or preventative action is advisable.

A further substantial section of the 1990 ACMP report provides a comprehensive review of the progress of the 1988 epidemic mortality among seals in the north east Atlantic. This affected seals around the North Sea, the Kattegat and SkAgerrak and the Irish Sea with 40-60% fatality. Only the seals around Scotland were relatively lightly affected. Most surviving seals appeared to have developed resistance to the viral cause of the disease by 1989 and comparatively few seal deaths were attributed to this cause during that year. Despite claims at the time, it is now apparent that contaminant burdens, accumulated in their bodies by the seals, played only a limited role in the severity of the epidemic, although there is an increasing body of evidence that suggests PCBs in particular pose a threat to seal well-being in some areas. The ACMP therefore notes in its 1990 report that in order to prevent further input to the sea there is a real need for the development and use of safe disposal and/or destruction methods for the PCBs that currently remain in use.

In some of its previous reports the ACMP has published what are described as overviews of contaminants. These are intended to summarize present

knowledge of sources, concentrations, fate and effects of the contaminants in question, and they are updated from time to time. The 1990 report contains such an update for hexachlorocyclohexane and hexachlorobenzene. It is concluded that neither compound at present poses a threat to aquatic wildlife. However, the different physical and chemical characteristics of the two compounds makes them particularly suitable as models for the likely behaviour of other trace organic compounds, which may otherwise present unrecognized threats to the well-being of aquatic organisms.

ICES has for a number of years engaged in a series of analytical intercomparison exercises. 1989-90 was no exception and brief details are provided in the 1990 ACMP report of the final results of an intercomparison exercise for nutrients in sea water and of progress with intercomparison exercises for polynuclear aromatic hydrocarbons and chlorobiphenyls. The nutrients exercise produced the predictable but nevertheless salutary proof that many laboratories cannot produce routinely reliable data on nutrient levels in sea water. This is an important finding given the present interest in, and importance of, trends in levels of nutrients in sea water over time.

ICES has also continued its work assessing data from monitoring of contaminant levels in biological tissues over a number of years. A report on the results of analysis of such data relative to contaminants in fish liver and in mussel tissue will be published in 1991. The

experience gained in this review is summarized in the 1990 ACMP report and its application to revision of the earlier ICES guidelines on the use of data on contaminants in biological and in various monitoring contexts is summarized. This is particularly pertinent in that several organizations have expressed interest in using a single sampling and analysis technique for several monitoring objectives. Unfortunately it appears this is only likely to be feasible if the most complex and time-consuming protocol is used. This is unlikely to provide good return for effort in most situations.

The ACMP has for a number of years been anxious to promote the application of biological effects techniques in routine monitoring studies. The 1990 report draws attention to the conduct, early in 1990, of a major workshop to apply simultaneously a wide variety of such techniques along transects that had previously been found to demonstrate gradients in pollutant levels. It is hoped that when the results are all available and assessed in 1991 it will be possible to recommend a number of the tested techniques, and to publish details of the successfully tested method in the ICES Techniques in Marine Sciences series. The first leaflet detailing a biological effects technique is due out early in 1991 and describes the procedure for the oyster embryo bioassay. This technique is currently being applied by the countries participating in studies organized under the North Sea Task Force.

Reference:

J.E. Portmann, 1991. Marine Pollution 1990. Marine Pollution Bulletin, 22: 152-153.