Ukraine's environmental problems include the nuclear contamination which resulted from the 1986 Chernobyl accident. One-tenth of Ukraine's land area was affected by the radiation. According to UN reports, approximately one million people were exposed to unsafe levels of radiation through the consumption of food. Approximately 3.5 million hectare (8.6 million acre) of agricultural land and 1.5 million hectare (3.7 million acre) of forest were also contaminated.
Pollution from other sources also poses a threat to the environment. Ukraine releases polluted water, heavy metal, organic compounds, and oil-related pollutants into the Black Sea. The water supply in some areas of the country contains toxic industrial chemicals up to 10 times the concentration considered to be within safety limits.
Air pollution is also a significant environmental problem in the Ukraine. In 1992, Ukraine had the world's seventh-highest level of industrial carbon dioxide emissions, which totaled 611.3 million metric tons, a per capita level of 11.72. However, in 2000, the total of carbon dioxide emissions was at 342.8 million metric tons. The pollution of the nation's water has resulted in large-scale elimination of the fish population, particularly in the Sea of Azov.
As of 2003, only 3.9% of Ukraine's total land area was protected, including 33 Wetlands of International Importance. According to a 2006 report issued by the International Union for Conservation of Nature and Natural Resources (IUCN), threatened species included 14 types of mammals, 13 species of birds, 2 types of reptiles, 11 species of fish, 14 species of invertebrates, and 1 species of plant. Threatened species include the European bison, the Russian desman, and the Dalmatian pelican. The wild horse has become extinct.