While the open oceans remain relatively unpolluted, many coastal areas are suffering from oil, sewage, industrial wastes, and agricultural run-off. This document presents some of the key facts related to these kinds of water pollution. It focuses on the major sources of contamination in the world's seas, and provides an overview of how these pollutants reach the oceans. A major portion of the brief summarizes what the United Nations Environment Programme (UNEP) is doing, beginning with the UN Conference on the Human Environment in 1972, and focusing on the development of regional action plans. It discusses the ocean monitoring activities of several international organizations and describes some of the actions taken to protect marine mammals. The document also provides a status report of the ten regional seas programs now in existence through UNEP. These programs focus upon: (1) the Mediterranean; (2) the Kuwait region; (3) the Wider Caribbean; (4) West and Central Africa; (5) Eastern Africa; (6) East Asia; (7) the Red Sea and the Gulf of Aden; (8) the South Pacific; (9) the South-east Pacific; and (10) South Asia. (TW)