Laboratory studies of dissolved radiolabelled microcystin-LR in lake water.
The fate of dissolved microcystin-LR was studied in laboratory experiments using surface water taken from a eutrophic lake. Based on initial range finding, a concentration of 50 microg l(-1) dissolved 14C-microcystin-LR was selected for subsequent time-course experiments. The first was performed in May before the cyanobacterial bloom season and low increases in the radioactivity of particulate fractions occurred with an approx. halving of the cyano-toxin during 4 days. The radioactivity of the dissolved fraction remained stable and there was no significant formation of radiolabelled inorganic carbon. A second time-course experiment was performed in September during the cyanobacterial bloom season. At the end of the four-day incubation period, the microcystin-LR concentration had decreased to an undetectable level and 24% of the added radiolabelled substance was found in different particulate fractions. The study demonstrated that biodegradation of dissolved microcystin-LR occurred in water collected at a lake surface with carbon dioxide as a major end-product.
Hyenstrand
Per
P
University of Dundee, School of Life Sciences, Division of Environmental and Applied Biology, DD1 4HN Dundee, UK.
Rohrlack
Thomas
T
Beattie
Kenneth A
KA
Metcalf
James S
JS
Codd
Geoffrey A
GA
Christoffersen
Kirsten
K
D001427:Bacterial Toxins / Q000032:analysis / Q000737:chemistry; D002250:Carbon Radioisotopes / Q000032:analysis; D000458:Cyanobacteria; D004784:Environmental Monitoring; D004791:Enzyme Inhibitors / Q000032:analysis* / Q000737:chemistry; D005068:Eutrophication; D008387:Marine Toxins / Q000032:analysis / Q000737:chemistry; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis* / Q000737:chemistry; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D012995:Solubility; D014881:Water Supply
D001427:Bacterial Toxins; D002250:Carbon Radioisotopes; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D010749:Phosphoprotein Phosphatases; C057862:cyanoginosin LR