Investigation of a toxic water-bloom of Microcystis aeruginosa (Cyanophyceae) in Lake Akersvatn, Norway

Berg, Kjetil; Carmichael, Wayne W.; Skulberg, Olav M.; Benestad, Christel; Underdall, Bjarne

doi:10.1007/bf00014522

Cited by 50 publications

(18 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has generally been found that 50-75% of bloom isolates are capable of producing toxins, with often more than one toxin (e.g., MCs and anatoxin-a) and several MC congeners being simultaneously produced. Concentrations of more than 24,000 Ag MCs/l have been reported from the shores of the Havel River, Berlin, Germany (Fastner et al, 1999) and Lake Akersvatn, Norway (Berg et al, 1987). Germany could exemplify for the widespread occurrence of toxic cyanobacterial blooms as documented in the literature (Wiedner et al, 2001).…”

Section: Microcystin: Risk Assessment and Guidance Values For Variousmentioning

confidence: 90%

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

Dietrich

Hoeger

2005

Toxicology and Applied Pharmacology

325

185

View full text Add to dashboard Cite

This article reviews current scientific knowledge on the toxicity and carcinogenicity of microcystins and compares this to the guidance values proposed for microcystins in water by the World Health Organization, and for blue-green algal food supplements by the Oregon State Department of Health. The basis of the risk assessment underlying these guidance values is viewed as being critical due to overt deficiencies in the data used for its generation: (i) use of one microcystin congener only (microcystin-LR), while the other presently known nearly 80 congeners are largely disregarded, (ii) new knowledge regarding potential neuro and renal toxicity of microcystins in humans and (iii) the inadequacies of assessing realistic microcystin exposures in humans and especially in children via blue-green algal food supplements. In reiterating the state-of-the-art toxicology database on microcystins and in the light of new data on the high degree of toxin contamination of algal food supplements, this review clearly demonstrates the need for improved kinetic data of microcystins in humans and for discussion concerning uncertainty factors, which may result in a lowering of the present guidance values and an increased routine control of water bodies and food supplements for toxin contamination. Similar to the approach taken previously by authorities for dioxin or PCB risk assessment, the use of a toxin equivalent approach to the risk assessment of microcystins is proposed. D

show abstract

Section: Microcystin: Risk Assessment and Guidance Values For Variousmentioning

confidence: 90%

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

Dietrich

Hoeger

2005

Toxicology and Applied Pharmacology

325

185

View full text Add to dashboard Cite

show abstract

“…The freeze-dried algae was added once to the test aquaria at the beginning of each experiment. The initial concentrations of cells were calculated to approximate those encountered in water and in scum (~109-1012 cells/L) during M. aeruginosa blooms (Berg et al, 1987;Zohary and Madeira, 1990;Watanabe et al, 1992). The corresponding initial toxin concentrations (Table 1) were in the same range as those of oscillatoria toxin encountered during Oscillatoria agardhii blooms where fish mortality was reported Lindholm, 1990).…”

Section: Exposure To Waterborne Algaementioning

confidence: 99%

Toxicity of Microcystis aeruginosa peptide toxin to yearling rainbow trout (Oncorhynchus mykiss)

1994

View full text Add to dashboard Cite

The effects of the blue-green algae (cyanobacterial) toxin microcystin-LR on yearling rainbow trout were studied in a series of intraperitoneal injection tests, gavage trials and exposures to waterborne algae. Concentrations of the microcystin-producing algae Microcystis aeruginosa known to occur during algae blooms (8-16 mg freeze-dried algae/L, i.e. approximately 1-2 × 1011 cells/L) were shown to be non-toxic to trout when present in aquarium water. On the other hand, trout died within 96 h when gavaged with an amount of algae equivalent to that which passed through the gills within 18 h in the aqueous exposure tests (1440 mg freeze-dried algae/kg body weight, i.e. 6600/.tg microcystin/kg body weight). Oral uptake of approximately one tenth of this dose (110 mg freeze-dried algae/kg body weight, i.e. 550/lg microcystin/kg body weight) proved to be non-toxic in single gavaging studies, but toxic within 96 h when orally administered 8 times at 12-h intervals. This study shows that the main uptake route of microcystin in trout is the gastrointestinal tract and that toxicity is manifested as massive hepatic necrosis. These results indicate that massive fish deaths reported at cyanobacterial bloom sites can be explained by the ingestion of toxic blue-green algae.

show abstract

“…Blooms of cyanobacteria have been repeatedly associated with eutrophication processes (Berg et al 1987, Carmichael et al 1988, Druvietis 1997, Pinckney et al 1998, Codd 2000, Chorus 2005). Factors such as high water retention time in lakes and reservoirs, increased temperature, low N:P ratio, as well as surface radiation and wind conditions have been reported to influence bloom development (Carmichael 1996, Kononen et al 1996, Kawara et al 1998, Chorus & Bartram 1999.…”

Section: Introductionmentioning

confidence: 99%

Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective

Galvão¹,

Reis²,

Valério³

et al. 2008

Aquat. Microb. Ecol.

View full text Add to dashboard Cite

This synthesis of 3 studies from 2 regions of southern Portugal (Alentejo and Algarve) was part of a workshop focusing on cyanobacteria held at the SAME 10. The first study monitored impacts of the large Alqueva dam on the Guadiana estuary since 1996, revealing changes in sediment load, nutrient regime and phytoplankton succession. Prior to dam construction, dense cyanobacterial blooms occurred in the upper estuary during summer and fall. After dam construction, chlorophyll concentration, phytoplankton diversity and abundances of cyanobacteria decreased, contrary to predictions. Mycrocystins remained at low levels in the seston and undetectable in water samples, except during summer 2003 when the particulate fraction contained 1 µg l -1 , while chlorophyll concentrations and abundances of potentially toxic cyanobacteria remained low. Algarve reservoirs studied since 2001 revealed differences in phytoplankton dynamics. In the western mesotrophic reservoirs (Bravura and Funcho), 40 to 50% of surface samples contained cyanobacterial concentrations of ≥2000 cells ml -1 , while over 80% of samples from the eastern oligotrophic reservoirs (Odeleite and Beliche) exceeded this value. Spring blooms were dominated by Oscillatoriales in Odeleite and Beliche and by Chroococcales in Bravura and Funcho. Bloom composition seemed to depend on water temperature and management strategies, while toxin concentrations reflected the increased biomass of toxic species. Finally, phytoplankton communities and microcystin production in 5 Alentejo freshwater reservoirs were studied from May to December 2005 and April to July 2006. Cyanobacterial blooms occurred, with varying intensities, not only during summer but also occasionally in winter. Microcystins were detected in 23% of the samples (n = 51), but without correlation with cyanobacterial biomass. Although Microcystis aeruginosa seemed to be the major producer of microcystins, other potentially toxic species were found. In summary, the varying pattern of cyanobacterial bloom occurrence and toxicity requires a systematic approach to monitoring programs for adequate risk assessment.

show abstract

Investigation of a toxic water-bloom of Microcystis aeruginosa (Cyanophyceae) in Lake Akersvatn, Norway

Cited by 50 publications

References 8 publications

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

Toxicity of Microcystis aeruginosa peptide toxin to yearling rainbow trout (Oncorhynchus mykiss)

Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective

Contact Info

Product

Resources

About