The first report of human deaths from exposure to cyanotoxins in Brazil occurred in Caruaru
(Pernambuco) in 1996, when during a hemodialysis procedure, 76 patients died from the
syndrome now known as "Caruaru Syndrome". Microcystins were found on the dialysis
clinic's carbon filter and in the patient's blood and liver.
On 29 December 2000, the Brazilian Health Minister published the 1469th Decree, including
guidelines for cyanobacteria and cyanotoxins in raw and treated water based on the World
Health Organization recommendations. The decree was then modified to the 518th Decree on
25 March 2004 and despite minor revisions, the cyanobacteria and cyanotoxin guidelines
were kept. The monitoring of cyanobacteria at Guandu Water Treatment Plant (ETA Guandu)
began in October 2001. ETA Guandu produces 43.000 cubic meters per second of treated
water and supplies nine million people in the Rio de Janeiro metropolitan region. During the
monitoring, a flood plain lake (Lake Guandu) was identified as the main cyanobacterial
source in the raw water. The cyanobacteria have been monitored monthly in Lake Guandu and
three times a week (or daily) in the raw water. Microcystins have been analyzed weekly by
tube kit, ELISA kit and/or HPLC in treated water. The monthly average cyanobacterial
concentrations in raw water was more than 10.000 cells mL-1 in five periods between 2002
and 2004. Aphanocapsa holsatica (Lemmermann) Cronberg & Komrek and Chroococcus
cronbergae Komrek & Novelo were the main species. Rainy days and the position of the
water intake were identified as factors that influence cyanobacterial plant entrance. Analysis
on raw and treated water during the blooms indicated cyanotoxins concentrations below the
guideline values (1µg L-1). Changes in the position of the water intake have been made during
the periods of bloom to reduce the entrance of cyanobacteria in the treatment plant and a
project to by pass the Lake Guandu's water from ETA Guandu intake has just been approved. Includes 20 references, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 550 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 06/17/2005 |
