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 ha (8.6 million ac) of agricultural land and 1.5 million ha (3.7 million ac) 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. In 1996, the total had dropped significantly to 397 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 2001, only 1.6% of Ukraine's total land area is protected, including 22 Wetlands of International Importance. Fifteen mammal species, 10 bird species, and 20 plant species are threatened, including the European bison, the Russian desman, and the Dalmatian pelican.