The algal toxin microcystin-LR has been identified in source and treated drinking
waters in the US (Carmichael, 2001; Karner et al., 2001). Chlorination has been shown
to inactivate microcystin-LR in several cases (Nicholson et al., 1994; Tsuji et al., 1997;
Hart et al., 1998; Bruchet et al., 1998). Since chlorination is extensively used in medium
and large water utilities in the US it is important to establish CT (contact time chlorine
concentration) values for the chlorination of microcystin-LR. The objective of this project
was to conduct an evaluation of the inactivation kinetics of extracellular microcystin-LR
by free chlorine. The analysis provided estimation of inactivation rate constants and CT
values needed for inactivation of the toxin.
Twenty-seven batch chlorine inactivation experiments of extracellular
microcystin-LR were performed. The chlorination experiments were run with three
different initial toxin concentrations (1, 3, and 10 ug/L), three different chlorine doses (1,
3, and 10 mg/L), and three different pH values (6.0, 7.5, and 9.0), at a temperature of
11C. All experiments were performed at five chlorination contact times, up to 100
minutes. Ascorbic acid was added as the chlorine quenching agent at the end of the
chlorination time. Microcystin-LR was quantified with enzyme linked immunosorbent
assay. For 19% of the samples, microcystin-LR was also quantified with high
performance liquid chromatography to provide additional confidence in the laboratory
results. The results of the two methods were correlated with an R2 of 0.904. Includes 6 references.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 220 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 3 |
| Published : | 11/02/2003 |
