Volume 2 (2009): Issue 2 (June 2009)

Cyanobacterial blooms in freshwaters represent a major ecological and human health problem worldwide. This paper briefly summarizes information on major cyanobacterial toxins (hepatotoxins, neurotoxins etc.) with special attention to microcystins - cyclic heptapeptides with high acute and chronic toxicities. Besides discussion of human health risks, microcystin ecotoxicology and consequent ecological risks are also highlighted. Although significant research attention has been paid to microcystins, cyanobacteria produce a wide range of currently unknown toxins, which will require research attention. Further research should also address possible additive, synergistic or antagonistic effects among different classes of cyanobacterial metabolites, as well as interactions with other toxic stressors such as metals or persistent organic pollutants.

An outline of the new European policy in the management of chemicals is given. This new system is known under the acronym REACH which stands for Registration, Evaluation and Authorisation of Chemicals. The background, objectives, requirements and the operation of REACH are briefly explained.

The meaning of alternative biotests is described and discussed. The paper also deals with the possible application of the developmental studies of the sea Artemia franciscana nauplinus. Five-day biotests including the validation criteria are described. The possibilities of the biotests are very wide. Additionally to the standard applications in ecotoxicology, there is a possibility of modelling pharmacological experiments or monitoring the effects of ionizing radiation and the interaction with other chemicals.

This article reports the most frequent cases of poisoning in farm animals, horses, cats, dogs, wild animals, fish and honey-bees in the Czech Republic. At present, there are fewer cases of acute poisoning caused by high doses of toxic substances but there are more and more cases of chronic poisoning as a consequence of environmental pollution.

Biosensors are analytical devices being approachable for multiple analytes assay. Here, biosensors with intercepted acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) are presented as tool for assay of anticholinergic compounds such as pesticides, nerve agents and some natural toxins. Principle of assay is based on evaluation of cholinesterase activity and its pertinent decrease in presence of analyte. Nerve agents, pesticides, anticholinergic drugs useable for treatment of Alzheimer's disease as well as myasthenia gravis and aflatoxins are enlisted as compounds simply analyzable by cholinesterase biosensors.

From the toxicological point of view, in the last two years melamine and cyanuric acid have become matters of great interest. These substances, especially melamine, have been abused during food and feed adulteration by increasing the content of nitrogen compounds in these products. Melamine and cyanuric acid as individual substances do not pose any serious risk in terms of toxicology. From the point of view of toxicology, it is especially the complex of melamine with cyanuric acid that is important. This complex, also known as the melamine-cyanurate complex, is a cause of human and animal health problems. In this work we present two examples of the incidence of melamine and cyanuric acid in two feed products originating from China. They were rice and the pea concentrates intended for animal nutrition. Protein concentrates can be the main risk factor for food chain contamination with melamine and cyanuric acid, especially those of unknown origin. Feed with a high content of nitrogen compounds and low content of aminoacids can be regarded as particularly suspicious. A comparison of results for determining nitrogen compounds and amines can be used as proof of adulteration of protein feeds. These feeds must be subjected to further analysis to determine melamine and cyanuric acid.