The GESAMP evaluation of potentially harmful substances in fish and other seafood with special reference to carcinogenic substances

Abstract

The joint Group of Experts on the Scientific Aspects of Marine Pollution, GESAMP (IMO/FAO/UNESCO/WMO/WHO/IAEA/UN/UNEP), has evaluated two groups of metals, (1) cadmium, lead and tin, and (2) arsenic, mercury and selenium, and has preliminarily discussed risks for ear effects arising from pollutants. These evaluations are based on work carried out within the GESAMP Working Group 13 and cover hazards to living resources as well as to human health. In this presentation only the human health aspects are discussed. Only under exceptional circumstances will cadmium intake from fish constitute an important part of the total daily intake via food. High consumption of certain shellfish may considerably increase the intake. Lead in seafood does not greatly contribute to the daily intake of lead. The contribution of seafood to the daily intake of tin is low. However, more data are needed for trimethyltin. Exposure to arsenic via seafood may be substantial. Most of this arsenic is in the form of arsenobetaine, which is considered relatively atoxic. Extreme seafood consumption may give rise to an intake of several hundred micrograms of inorganic arsenic per day; an exposure level which over a lifetime may be related to a significant increase in skin cancer. Groups with high fish intake or intake of fish with a high methylmercury content can easily exceed the WHO/FAO provisional tolerable intake level. Pregnant women constitute a special risk group. A coordinated research approach on an international basis is needed to obtain the necessary data to establish valid guidelines. Selenium does not pose a toxicological problem. Its importance as related to different mercury compounds is discussed. Preliminary evaluations of the risks for carcinogenic effects have been carried out, partly in collaboration with the WHO International Agency for Research on Cancer. Taking all the evidence into account it was considered as a matter of urgency to mobilize the necessary support for the further development and acceleration of work on the impact of carcinogenic substances on marine organisms and the implications for public health.