About 520 sq km (200 sq mi) of reclaimed coastal land is protected from the sea by concrete dikes. As of 2000, Belgium's most significant environmental problems were air, land and water pollution due to the heavy concentration of industrial facilities in the country. The sources of pollution range from nuclear radiation to mercury from industry and pesticides from agricultural activity. The country's water supply is threatened by hazardous levels of heavy metals, mercury, and phosphorous. It has a renewable water supply of 12 cu km. Pollution of rivers and canals was considered the worst in Europe as of 1970, when strict water-protection laws were enacted. Air pollution reaches dangerous levels due to high concentrations of lead and hydrocarbons. Belgium is also among the 50 nations that emit the highest levels of carbon dioxide from industrial sources. In 1996 its emission level was 106 million metric tons. Belgium's problems with air pollution have also affected neighboring countries by contributing to the conditions which cause acid rain. The Ministry of Public Health and Environment is Belgium's principal environmental agency, and there is also a Secretary of State for Public Health and Environment. The Belgian government has created several environmental policies to eliminate the country's pollution problems: the 1990–95 plan on Mature Development, an Environmental Policy Plan, and the Waste Plan.
As of 2001, there were six species of mammals and three species of birds that were endangered. The Mediterranean mouflon, the Atlantic sturgeon, and the black right whale are listed as endangered.