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Akutní a chronické působení neonikotinoidových látek na vodní organismy
STROUHOVÁ, Alžběta
Neonicotinoids, synthetic substances derived from the natural alkaloid nicotine, are one of the newest class of pesticides. Neonicotinoids are selective for invertebrate nicotinic acetylcholine receptors (nAChRs) and are widely used to treat crops around the word. The aim of this study was to evaluate acute and chronic toxicity of neonicotinoid substance acetamiprid and neonicotinoid product Mospilan 20 SP, which contains 20 % of acetamiprid, to aquatic organisms. Chronic effects to the biochemical profile of haemolymph, oxidative stress biomarker and antioxidant biomarkers have been evaluated too. Marbled crayfish (Procambarus virginalis) was used as a model organism to provide the toxicity. The acute toxicity (96hLC50) of the pure neonicotinoid substance acetamiprid to marbled crayfish is 0.8 mg.l-1, of Mospilan it is 2.71 mg.l-1. The theoretical acute toxicity of Mospilan is 4.0 mg.l-1. It was calculated based on the acute toxicity of pure acetamiprid as the active substance of Mospilan. Additives in the preparation probably contributes its toxicity more than the active substance itself. Acetamiprid and Mospilan impact on changes in the levels of biomarkers of the biochemical profile of haemolymph, biomarker of oxidative stress and antioxidant biomarkers. Changes in the levels of biomarkers are already manifested at concentrations corresponding to 0,1 % and 1 % of 96hLC50. These changes include increases in GLU, AST, ALT and LDH levels, decreases in CAT and GST activity and changes in LPO level.
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Neonikotinoidy ve vodních ekosystémech a jejich vliv na necílové organismy
STROUHOVÁ, Alžběta
Neonicotinoids are one of the newesst class of pesticides, used in agriculture like insecticides. The first neonicotinoids has been used since the early 1990s, they become very popular and widely used worldwile for their low toxicity for vertebrates. Neonicotinoids were considered to be less toxic to aquatic organisms due to their low toxicity to standard test organisms Daphnia magna and Rainbow trout (Onchorhynchus mykiss), but recent studies have shown the opposite of this assumption. Partial aim of this study was, among summary of existing knowledges of the neonicotinoids in aquatic ecosystem and their impact on non-target organisms, also evidence toxicity of neonicotinoid preparation CALYPSO 480 SC, which contains 48 % of thiacloprid. Three species of crayfish were used to provide the toxicity Red swamp crayfish (Procambarus clarkii), Marbled crayfish (Procambarus fallax) and Yabby (Cherax destructor). To asses the toxiciy of Calypso, the acute toxicity tests on crayfish and acute immobilisation test on daphnia were used. The exposure time of tests were 96 and 48 hours. Juvenile crayfish were the most sensitive, their 96hLC50 ranged between 0.52 and 1.6 mg/l, 96hLC50 for older crayfish were between 1.94 and 27.3 mg/l. The 48hEC50 value for daphnia was 32.7 mg/l. During the acute toxicity test on crayfish, out of the mortality, changes in behavior of orgaisms were observed, the most frequent changes were the reduction of aggressiveness, slowing of motion of limbs, gills and breathing. Crayfish turned on their back, individuals were apathetic and died.
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