My Bloom changed from Blum (likely closer to the Cyrillic transliteration) in Cleveland in the early 20th C. Best I can tell, the family is from Bauska, Latvia, although there are mentions of Kuldiga, Goldengen, Riga, and Broush (can't find this one anywhere). The only pre-immigration ancestor I can find anything about is Avraham Dov Blum (b. approx 1820, d. 1897).
David Bloom
Mt Vernon, WA