Prospective study of acute health effects in relation to exposure to cyanobacteria

• Published in: The Science of the total environment 2014-01, Vol.466-467, p.397-403
• Main Authors: Lévesque, Benoît, Gervais, Marie-Christine, Chevalier, Pierre, Gauvin, Denis, Anassour-Laouan-Sidi, Elhadji, Gingras, Suzanne, Fortin, Nathalie, Brisson, Geneviève, Greer, Charles, Bird, David
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Bathing; Child; Cyanobacteria; Cyanobacteria - isolation & purification; Cyanobacteria - physiology; Drinking water; Drinking Water - microbiology; Environmental Exposure; Environmental Monitoring; Female; Humans; Male; Microcystin; Microcystins - toxicity; Middle Aged; Prospective Studies; Public Health; Quebec; Recreational water; Risk Assessment; Water Pollutants, Chemical - toxicity; Young Adult
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2013.07.045

We conducted a study to investigate the relationship between exposure to cyanobacteria and microcystins and the incidence of symptoms in humans living in close proximity to lakes affected by cyanobacteria. The design was a prospective study of residents living around three lakes (Canada), one of which has a water treatment plant supplying potable water to local residents. Participants had to keep a daily journal of symptoms and record contact (full or limited) with the water body. Samples were collected to document cyanobacteria and microcystin concentrations. Symptoms potentially associated with cyanobacteria (gastrointestinal: 2 indices (GI1: diarrhea or abdominal pain or nausea or vomiting; GI2: diarrhea or vomiting or [nausea and fever] or [abdominal cramps and fever]); upper and lower respiratory tract; eye; ear; skin; muscle pain; headaches; mouth ulcers) were examined in relation with exposure to cyanobacteria and microcystin by using Poisson regression. Only gastrointestinal symptoms were associated with recreational contact. Globally, there was a significant increase in adjusted relative risk (RR) with higher cyanobacterial cell counts for GI2 (100,000cells/mL: RR=3.28, 95% CI=1.69–6.37, p-trend=0.001). In participants who received their drinking water supply from a plant whose source was contaminated by cyanobacteria, an increase in muscle pain (RR=5.16; 95% CI=2.93–9.07) and gastrointestinal (GI1: RR=3.87; 95% CI=1.62–9.21; GI2: RR=2.84; 95% CI=0.82–9.79), skin (RR=2.65; 95% CI=1.09–6.44) and ear symptoms (RR=6.10; 95% CI=2.48–15.03) was observed. The population should be made aware of the risks of gastrointestinal symptoms associated with contact (full or limited) with cyanobacteria. A risk management plan is needed for water treatment plants that draw their water from a source contaminated with cyanobacteria. •The relationship between exposure to cyanobacteria and health symptoms was examined.•Limited water contact with cyanobacteria was linked to gastrointestinal symptoms.•Drinking water contaminated by cyanobacteria was associated with health symptoms.•The public should be informed of symptoms associated with exposure to cyanobacteria.•A management plan is needed for plants treating cyanobacteria-contaminated water.