Cyanobacterial toxins in Lake Baringo, Kenya

Abstract

This paper presents data on the first identification, characterization and quantification of hepatotoxic microcystins and neurotoxic anatoxin-a in water samples of Lake Baringo,Kenya. The shallow turbid Lake Baringo was investigated five times between June 2001 and May 2002. The phytoplankton community was mainly dominated by the cyanobacterium Microcystis aeruginosa. Due to the high turbidity the phytoplankton biomass was low, rang-ing between 1.5 and 8.2 mg L -1. High mean total phosphorus concentration (1.0 mg L -1) and mean total nitrogen concentration (2.8 mg L -1) typical for hypertrophic lakes were found.Using HPLC technique the hepatotoxins microcystin-LR, -RR and -YR and the neurotoxin anatoxin-a were detected in the water samples. The microcystin concentrations varied from 310 to 19800 gg microcystin-LR equivalents g-1 DW and the anatoxin-a concentration ranged from 270 to 1260 ~g g-~ DW. To our knowledge this is the first evidence of cyanobac-terial toxins in Lake Baringo.