These include infertility and reproductive failure, birth defects, cancer, behavioral change, immune and nervous system dysfunction, damage to kidneys, liver and other organs, and alteration of hormone levels. The Context There are many uncertainties over the current and potential future effects of pollutants on marine mammals and their populations. The toxicity of the vast majority of chemicals now released into the environment is very poorly known, and is even less so for the interactive effects of complex mixtures, the typical environmen-tal scenario. Little is known about the cumulative effects of contaminants in conjunction with the variety of other stresses facing marine mammals, or on the effects of contaminant-induced foodweb changes. It is expected, however, that hitherto unrealised impacts will be uncov-ered as scientific knowledge increases.
Most POPs are also semivolatile which has meant their global spread via the atmosphere.
Negotiations towards an international and legally binding agreement are currently underway. Further Reading Boer, J. et al. Colborn,T. and Smolen, M.J. 1996. Epidemiological analysis of persistent organochlorine contaminants in cetaceans. Marine Mammal Commission.