title: Recreational exposure to low concentrations of microcystins during an algal bloom in a small lake.
abstract: We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-microg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses), but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 microg/L to 5 microg/L) in the water and (<0.1 ng/m(3)) in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147 microg/L). Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins.
authors: National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Chamblee, Georgia 30341, USA. lbacker@cdc.gov
authors: Lorraine C
authors: LC
authors: Backer
authors: Wayne
authors: W
authors: Carmichael
authors: Barbara
authors: B
authors: Kirkpatrick
authors: Christopher
authors: C
authors: Williams
authors: Mitch
authors: M
authors: Irvin
authors: Yue
authors: Y
authors: Zhou
authors: Trisha B
authors: TB
authors: Johnson
authors: Kate
authors: K
authors: Nierenberg
authors: Vincent R
authors: VR
authors: Hill
authors: Stephanie M
authors: SM
authors: Kieszak
authors: Yung-Sung
authors: YS
authors: Cheng
mesh_terms: D000293:Adolescent; D000328:Adult; D000336:Aerosols; D000368:Aged; D002648:Child; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D005068:Eutrophication; D005260:Female; D005618:Fresh Water / Q000382:microbiology*; D006801:Humans; D008297:Male; D052998:Microcystins / Q000008:administration & dosage / Q000097:blood / Q000633:toxicity*; D046931:Microcystis / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D008875:Middle Aged; D011634:Public Health; D011998:Recreation; D014481:United States; D014919:Wind; D055815:Young Adult
chemical_list: D000336:Aerosols; D052998:Microcystins