title: Laboratory studies of dissolved radiolabelled microcystin-LR in lake water.
abstract: 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.
authors.affiliation: University of Dundee, School of Life Sciences, Division of Environmental and Applied Biology, DD1 4HN Dundee, UK.
authors.forename: Per
authors.initials: P
authors.lastname: Hyenstrand
authors.forename: Thomas
authors.initials: T
authors.lastname: Rohrlack
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Beattie
authors.forename: James S
authors.initials: JS
authors.lastname: Metcalf
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Codd
authors.forename: Kirsten
authors.initials: K
authors.lastname: Christoffersen
mesh_terms: 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
chemical_list: D001427:Bacterial Toxins; D002250:Carbon Radioisotopes; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D010749:Phosphoprotein Phosphatases; C057862:cyanoginosin LR