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The Behaviour of Atrazine under Denitrification Conditions
Pániková, Kristína
Atrazine is one of the most persistent pesticides. This substance negatively affects the environment and the human body. It is a frequent contaminant of groundwater, in which ideal conditions for the denitrification process prevail. Using a methodology of long-term testing, atrazine was investigated under denitrification conditions, as well as its transformation behaviour and effect on the denitrification process itself. After 28 days, adsorption on poplar shavings was observed as the dominant process, 30.6%. A biotic loss of 9.8% was found, and, at a concentration of 0.1 mg/l, atrazine did not significantly affect the denitrification process. Stimulation reached the value of 6.9%.
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Hodnocení subchronického působení atrazinu na raka (Cherax destructor)
HLÁVKOVÁ, Markéta
The evaluation of the sub-chronic exposure to atrazine on crayfish The aim of this study is to evaluate the sub-chronic effect of atrazin on a behaviour, oxidative stress, antioxidant enzyme aktivities and biochemical profile of haemolymph in. These complex data should help to appraise the impact of this substance in the environment. The total test duration was 28 days and was divided into two periods. The first 14 days the crayfish were exposed to two concentrations of atrazine: 6.86 micrograms per liter (ATRenv = environmental concentration in the water in the Czech Republic) and 1.21 milligrams per liter (ATR10% = is coincident to 10% LC50). After the atrazine treatments the depuration 2 weeks phases in water without any chemicals followed. The results indicate that sub-chronic effect of atrazine influenced neither the behaviour of the crayfish nor the level of oxidative stress (measured by TBARS), whereas the changes of superoxiddismutase (SOD) were observed in all tissues (muscles, gills and hepatopancreas). The changes of enzyme activity were observed in catalase (CAT; hepatopancreas and the muscle tissue), glutathione S-transferase (hepatopancreas and the gills tissue), glutathione reductase (GR; the hepatopancreas tissue) and reduced glutathione (the muscle tissue). The influence of ATRenv on the biochemical profile of haemolymph at the following parameters was estimated only for lactate and alkaline, however phosphatase changes made by ATR10% were significant for glucose, ammonia, lactate and alkaline phosphatase measurements. The sub-chronical effect changed the activity of all antioxidant enzymes in hepatopancreas, muscles and the gills tissue of the observed crayfish. The presented results in this study are giving compact information of impact of atrazine on the crayfish and the whole water environment. The suggestion of using the crayfish for tests of toxicity looks like an ideal supplement for triazine herbicide estimations.
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Endocrine disruptors in reptiles
Semerád, Jaroslav ; Kratochvíl, Lukáš (advisor) ; Cajthaml, Tomáš (referee)
The ability of environmental contaminants to influence reproduction and development in vertebrates via disruption of the endocrine system is widespread. The mechanisms through which xenobiotics act can be complex and vary greatly among species. Reptiles are particularly good models for studying endocrine affecting compounds due to the fact that different species differ in modes of sex determination (genotypic sex determination or temperature-dependent sex determination) and parity (oviparity or viviparity). The sex of individual is often determined by egg incubation temperature, and exogenous application of steroid hormones and their analogs or steroidogenic enzyme inhibitors can reproduce effects of temperature. The lability of sex determination in some reptile species offers opportunity to use gonadal sex as a marker for effects of endocrine disrupting compounds (EDC), even for the effects of extremely low dosages of EDCs or EDC mixtures. The neonatal offsprings exposed to EDCs during embryogenesis provide yet another way to assess endocrine disruption, i.e., measurement of steroid hormone levels in their blood. In addition, many reptile species are highly aquatic, they use habitats near agricultural areas, where usage of pesticides is the most intense, and they are carnivores or scavengers. Therefore,...
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Establishment of method for determination of selected triazine pesticides in water using GC-MS/MS
OPEKAR, Jan
This bachelor thesis deals with the determination of triazine pesticides in water using GC-MS/MS. Firstly, the development and optimisation of an analytical method was performed. The following parameters of the analytical method were chosen for optimisation: carrier gas flow rate, temperature gradient, selection of SRM transitions and collision energy of SRM transitions. Then, several extraction parametres such as SPE column drying time, selection of elution solvent, sample pH and sample volume were optimised. Finally, the method was successfully validated and applied to the analysis of a real tap water sample.
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