Occurrence of microcystins in raw water sources and treated drinking water of Finnish waterworks

Abstract

Problems caused by cyanobacteria are common around the world and also in raw water sources of drinking water treatment plants. Strains belonging to genera Microcystis, Anabaena and Planktothrix produce potent hepatotoxins, the microcystins. Laboratory and pilot scale studies have shown that microcystins dissolved in water may pass the conventional surface water treatment processes. In 1998 the World Health Organization proposed a guide value of 1 microgram/L for microcystin-LR (MC-LR) in drinking water. The purpose of this research was to study the occurrence of microcystins in raw water sources of surface waterworks and in bank filtration plants and to evaluate the removal of microcystins in operating waterworks. Four bank filtration plants and nine surface waterworks using different processes for water treatment were monitored. Phytoplankton was identified and quantified, and microcystins analysed with sensitive immunoassay. Microcystin occurrence in selected water samples was verified with HPLC and a protein phosphatase inhibition method. Microcystins were detected sporadically in raw water sources of most of the waterworks. In two raw water supplies toxins were detected for several months. The highest microcystin concentrations in incoming raw water were approximately 10 micrograms/L MC-LR equivalents. In treated drinking water microcystins were detected occasionally but the concentrations were always below the guide value proposed by WHO.

Elimination of Botulinum Neurotoxin (BoNT) Type B from Drinking Water by Small-Scale (Personal-Use) Water Purification Devices and Detection of BoNT in Water Samples

“…c A mixture of seven toxic C. botulinum type B strains ( this most probably is strongly dependent on the thickness of the sand bed and properties of the sand used (21,25). In the present study, the 254-nm UV irradiation produced by the low-pressure lamp was not able to degrade BoNT in the water.…”

Influence of Cyanobacterial Bloom on Freshwater Biocoenosis. Use of Bioassays for Cyanobacterial Microcystins Toxicity Assessment

“…According to the Dockal and Soldan scale, the LC 50 result was evaluated as highly toxic, according to EPA moderately toxic, and according to EWG (ACE 89/BE 2/D3) as toxic (2 nd class of toxicity). The compared toxicity scales are taken from Łebkowska et al [26] The stimulation of heterotrophic bacteria growth (Pseudomonas putida) affected by extracts containing cyanobacterial hepatotoxins and neurotoxins was also observed by Lahti et al [22]. The inhibition or growth of four species of heterotrophic bacteria: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus was noted in the study of Ibraheem et al [15] for cyanobacterial supernatants of eight cyanobacteria species: six belonging to Nostoc sp., and two of Anabaena sp.…”

Cyanotoxins in Serbia and water treatment procedures for their elimination

“…Biologically active filtration, both slow and rapid filtration, have been reported to remove or to inactivate MCs in drinking water (Lahti, et al, 2001;Bourne, et al, 2006). Some studies have shown that direct rapid filtration was not effective in removing cyanobacterial cells, while slow sand filters can remove 99% of the cells (Lepisto, et al, 1994;Mouchet, Bonnelye, 1998;Grutzmacher, et al, 2002).…”