Ondřej Adamovský


Bioaccumulation and effects of cyanotoxins in the aquatic environment


Masaryk University, Faculty of Science,

Research Centre for Toxic Compounds in the Environment (RECETOX)

Brno, Czech Republic, 2010



Abstract


Massive development of toxic cyanobacterial bloom in freshwater is an unwanted consequence of
nutrient pollution of aquatic ecosystems. Cyanobacterial blooms are common phenomena occurring
worldwide in recreational and drinking water reservoirs or fish ponds including Czech Republic.
Cyanobacterial toxins (cyanotoxins) belong among the problems connected with cyanobacteria. Their
production negatively influences the organisms in aquatic as well as terrestrial ecosystem. The
most studied and the most common group of cyanotoxins are hepatotoxic microcystins.


This work is focused on accumulation and elimination of microcystins in fish and birds and
evaluation of oxidative stress and toxic effects of cyanobacterial biomass containing cyanotoxins.
Results of our studies bring new information about kinetics of accumulation of microcystins in two
ecologically different fish species and demonstrate concentrations of microcystins in individual
fish organs such as muscle and hepatopancreas. Further, we have studied elimination of
microcystins, and the results showed relatively fast elimination of microcystins from
hepatopancreas and muscle of the fish.


This thesis also addressed the accumulation of microcystins and the influence of toxins on
oxidative stress in birds. Accumulation of microcystins in the muscle and liver of birds was
observed during feedings studies, and the impact of combined co-exposures of various stressors on
final microcystin concentrations in the tissues were evaluated.


            One of the chapters is also focused on the evaluation of the health risks for humans
resulting from the consumption of food (edible fish muscle) contaminated with microcystins. The
results from our experiments show relatively low risk. Specific part of the present work also
studied the effects of cyanobacterial biomass on fish including the quality of the fish muscles.
Interestingly, our studies showed only minor impact of cyanobacteria on the dietetic value of the
fish meat.