Identification and quantification of microcystins from a Nostoc muscorum bloom occurring in Ouka meden River (High-Atlas mountains of Marrakech, Morocco)

• Tipo: Artigo em Revista Científica Internacional
• Data: 2009

Autores

Oudra, B (Autor) Outra; Dadi El E Andaloussi (Autor) Outra; Vasconcelos, VM (Autor) FCUP

Revista

Título: Environmental Monitoring and Assessment

Vol. 149

Páginas: 437-444

ISSN: 0167-6369

Editora: Springer Nature

Indexação

ISI Web of Knowledge - 37 Citações

Scopus - 42 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Ciências da terra e ciências do ambiente

Outras Informações

ID Authenticus: P-003-NDP

DOI: 10.1007/s10661-008-0220-y

Abstract (EN): Health risks generated by cyanobacterial toxins in drinking and recreational waters are clearly recognised. During the monitoring programme on the distribution of toxic freshwater cyanobacteria in various water bodies including reservoirs, ponds and rivers of Morocco, many toxigenic cyanobacteria bloom-forming species have been identified. Particular attention was given to the investigation of the toxicology of a benthic Nostoc species-Nostoc muscorum Ag. (cyanobacteria, Nostocales, Nostocaceae)-that was found dominant in Ouka meden river located at 2,600 m of altitude in High-Atlas mountains of Marrakech. The massive growth of the matforming N. muscorum occurred yearly during the period of March-October, when the water temperature was above 10 C. During 1997-1999, samples were collected from either floating or benthic mats. Hepatotoxicity associated to gastrointestinal (diarrhoea) intoxication symptoms was confirmed by intraperitoneal (i.p.) injection in mice of N. muscorum thallus extract. The survival time was estimated to be from 2-5 h, and the calculated i.p. LD(50) in mice ranged from 15 to 125 mg kg(-1) body weight. The application of the high performance liquid chromatography with photodiode array detection confirmed the occurrence of microcystin-LR (MC-LR) and three others microcystin variants from the methanolic Nostoc extract. The MC-LR represented a proportion of 39% of the total microcystin content however, the total concentration equivalents-eq-of MC-LR was estimated to be 139 mu g MC-LR eq per gram dry weight. The existence of a benthic microcystin-producing N. muscorum strain under the particular environmental conditions of Ouka meden region may be a potential human health hazard and the ecological harmful effects of these cyanobacterial toxins need to be assessed. This paper constitutes the first report of the occurrence of a toxic benthic Nostoc in Morocco. So, the benthic species should be considered during monitoring of toxic Cyanobacteria particularly for river used for source of drinking water.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8