The objective of this study was to evaluate the quality of raw and treated water from six
treatment plants in Quebec whose water supply is affected by cyanobacterial blooms. High levels of
cyanobacteria were identified in raw water samples collected from all six plants from July to
November 2001-2004. At least one cyanotoxin was detected in 43% of the samples, with up to 5.3
µg/L of microcystins and 2.3 µg/L of anatoxin-a. Given the threat to human health posed by the
ingestion and inhalation of cyanotoxins and cyanobacteria, their levels in raw water demonstrate the
need for effective treatments to remove them. Samples from the six plants showed that, in general,
treated water contained very low levels of cyanobacteria (around 200 cells/mL), and low turbidity
levels (<0.5 NTU). Moreover, only 5% of the treated water samples had detectable concentrations of
cyanotoxins, with a maximum value of 0.1 µg/L for microcystin-LR (10 to 15 times lower than
recommended maximum available concentrations). While confirming the safety of the drinking water
produced by the six treatment plants currently affected in Quebec, the study also showed that the plants
are vulnerable to the impacts of pollution, and pointed to the need to further protect and restore lakes
and rivers that serve as drinking water sources. Includes 15 references, tables, figure.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 220 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 7 |
| Published : | 11/01/2005 |
