Abstract

We hypothesized that unusual deaths and illnesses in wild and domestic animals in lake areas of the Rift Valley south of Addis Ababa were caused by toxic cyanobacteria. In the first cyanotoxic analyses conducted in samples from Ethiopia, we found lakes Chamo, Abaya, Awassa, Chitu, Langano, Ziway, and Koka all had concentrations of microcystins (MC) ranging from trace to hazardous, whereas only traces less than limits of detection (LOD) of cylindrospermopsin (CYN) were found. In the December 2006 dry season we sampled the lakes for analyses of MC, CYN, species structures, and calculations of cyanobacteria biomass. We used the Utermol technique to analyse cyanobacterial biomass and monitored MC toxins using HPLC-DAD, LC-ESI-MS-MRM, and ELISA-test and CYN with HPLC-DAD and ELISA. The various toxicity tests coincided well. In 4 of the lakes (Chamo, Langano, Ziway, and Koka), the inter-lake range of total MC concentration was 1.3-48 mu g L-1; in 3 (Abaya, Awassa, and Chitu), we found only traces of MC. Microcystis aeruginosa was the dominant species, with Microcystis panniformis, Anabaena spiroides, and Cylindrospermopsis spp. as subdominants. The MC concentration, especially in Lake Koka, exceeded levels for serious health hazards for humans, cattle, and wildlife.

Keywords

CyanoHAB; cylindrospermosin; ELISA; Ethiopian Rift Valley lakes; HPLC; mass spectrometry; microcystins; Microcystis

Published in

Inland Waters
2011, Volume: 1, number: 2, pages: 81-91
Publisher: FRESHWATER BIOLOGICAL ASSOC

SLU Authors

• Willén, Eva

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Fish and Aquacultural Science
Environmental Sciences related to Agriculture and Land-use


Publication identifier

DOI: https://doi.org/10.5268/IW-1.2.391

Permanent link to this page (URI)

https://res.slu.se/id/publ/57421