Littleton Community Farm will sponsor a free screening of the documentary film “Marion Stoddart: The Work of 1000” at 6 p.m. Monday in the Reuben Hoar Library, 41 Shattuck St. The documentary, produced and directed by Pepperell resident Susan Edwards, relates the story of how Stoddart, a self-described ordinary woman from Groton, was able to accomplish the extraordinary in mobilizing a cleanup of the Nashua River. Beginning in 1962, Stoddart successfully lobbied for legislation, including the Massachusetts Clean Waters Act. She petitioned the federal government for millions of dollars of promised antipollution funds and won, and in 1969 she cofounded the Nashua River Watershed Association. Stoddart will be at the screening to discuss her work and answer questions, and will be joined by Jennifer Stach from Littleton Community Farm and David Outman from the town’s Open Space Committee.