Chronic marine contamination has a serious impact on creatures living in the sea, and is closely related to mass death, reproductive disorders, deformations and the declined immune function of living things. Investigations of Caspian seals that have died in large numbers several times in the past show surprising results that include the detection of dozens of times the concentration of organic chlorine-based chemical compounds in comparison with healthy Caspian seals. It is necessary to promote the reinforcement of an international monitoring system, and the establishment of an investigative research organization related to marine contamination.