AWWA ACE61826

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 thesyndrome now known as "Caruaru Syndrome". Microcystins were found on the dialysisclinic's carbon filter and in the patient's blood and liver.On 29 December 2000, the Brazilian Health Minister published the 1469th Decree, includingguidelines for cyanobacteria and cyanotoxins in raw and treated water based on the WorldHealth Organization recommendations. The decree was then modified to the 518th Decree on25 March 2004 and despite minor revisions, the cyanobacteria and cyanotoxin guidelineswere 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 treatedwater and supplies nine million people in the Rio de Janeiro metropolitan region. During themonitoring, a flood plain lake (Lake Guandu) was identified as the main cyanobacterialsource in the raw water. The cyanobacteria have been monitored monthly in Lake Guandu andthree times a week (or daily) in the raw water. Microcystins have been analyzed weekly bytube kit, ELISA kit and/or HPLC in treated water. The monthly average cyanobacterialconcentrations in raw water was more than 10.000 cells mL-1 in five periods between 2002and 2004. Aphanocapsa holsatica (Lemmermann) Cronberg & Komrek and Chroococcuscronbergae Komrek & Novelo were the main species. Rainy days and the position of thewater intake were identified as factors that influence cyanobacterial plant entrance. Analysison raw and treated water during the blooms indicated cyanotoxins concentrations below theguideline values (1µg L-1). Changes in the position of the water intake have been made duringthe periods of bloom to reduce the entrance of cyanobacteria in the treatment plant and aproject to by pass the Lake Guandu's water from ETA Guandu intake has just been approved. Includes 20 references, figures.

Product Details

Edition:

Vol. - No.

Published:

06/17/2005

Number of Pages:

10

File Size:

1 file , 550 KB