Bitterfeld (bĭˈtərfĕlt) [key], city (1994 pop. 17,030), Saxony-Anhalt district, E Germany, on the Mulde River. It is an industrial center and rail junction, but industrial development has led it to be one of the most polluted cities in Europe. Manufactures include chemicals, aluminum, machinery, and plastics. Lignite is mined in the region. Bitterfeld was founded in the mid-12th cent. and passed to Prussia in 1815.