The School of Population Health, The University of Queensland undertook a study of the Recreational Exposure to Freshwater Cyanobacteria. The aim of this project was to enhance the understanding of public health issues relating to recreational exposure to cyanobacteria by conducting epidemiological and laboratory-based toxicology studies. The study produced 418 pages of detailed information.
A prospective cohort study of 1,331 recreational water users was conducted at various sites in southern Queensland, the Myall Lakes area of New South Wales, and central Florida. The study design sought to make improvements over previously published epidemiological studies, in that an unexposed group was recruited from cyanobacteria-free waters, cyanobacterial toxins were measured in site water samples, and respondents were asked to rate the severity of reported symptoms. This study has shown an increased likelihood of symptom reporting amongst bathers exposed to high cyanobacterial cell density (measured by total cell surface area) compared to those exposed to low cyanobacteria-affected waters. Mild respiratory symptoms appear to be the predominant symptom category.
This is a very comprehensive study you can review the entire document at http://espace.library.uq.edu.au/eserv/UQ:9880/is_thesis_mar06.pdf