Solidarity trade union founder Lech Walesa will be placed on trial for challenging the official voter turnout figures in Polish parliamentary elections last October, government spokesman Jerzy Urban said. Walesa, 42, winner of the 1983 Nobel Peace Prize, is formally charged with slander. If convicted, he could be jailed for as long as two years. A prosecutor in December questioned Walesa about allegations that he challenged turnout figures released by the government after the elections. Walesa contended that the turnout was 60%, not the official figure of 79%. Walesa based his turnout figures on union monitoring.