AdvertisementPoisonous Algae Blooms Threaten People, Ecosystems Across U.S.August 29, 2016Lesley McClurgfacebookEmailOfficials found the toxin microcystin in the blue-green algae present at Discovery Bay, Calif. For people exposed to the toxin, symptoms include dizziness, rashes, fever, vomiting and in more unusual cases, numbness. (KQED)