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Concentration of nickel in wastewater and its removal using a constructed wetland
KOUKLÍKOVÁ, Etela
This bachelor thesis is focused on the determination of the efficiency of the nickel removal from wastewater using constructed wetlands. During 2015, wastewater from the vegetation wastewater treatment plant in the villageSlavošovice was analyzed. Nickel concentration in wastewater was determined by atomic absorption spectrometry. Samples of wastewater were taken eight times from six different parts of the wetland. The obtained results of the wastewater analysis I evaluated the degree of the nickel removal in the profile of the vegetation wastewater treatment plant. The analysis was conducted using an atomic absorption spectrometer Thermo Scientific iCE 3500. The characteristics of the analytical method were as follows: accuracy (97.64%), precision (3.53%), sensitivity (9 x 10-3 s.l/g), limit of detection (LOD = 0.161 ?g /l), limit of quantification (LOQ = 0.537 ?g/l), linear dynamic range (0,537 - 10 ?g/l) and correlation coefficient (0.9992). The concentration of nickel obtained from samples from the inflow zone differed by several tenths or units of ?g/l compared to the inflow concentration value. The nickel of concentration at the outflow from the system was decreased by units of ?g/l compared to the inflow. The gradual decrease of the concentration of nickel was observed for the samples taken from the profile of the constructed wetland vegetated bed. The obtained results document the sufficient efficiency of the nickel removal from municipal wastewater in Slavošovice constructed wetland. The outflowing water, guided to a nearby stream, contains lower concentrations of nickel in comparison with the raw wastewater. With respect to aquatic organisms, it is very important to reduce the concentration of nickel in treated wastewater. Actually, the nickel toxicity for aquatic organisms is much higher than for humans.
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Determination of mercury in selected foods
HAVLOVÁ, Michaela
The thesis resolves problems about the contain of mercury in chosen articles of food. Mercury, hydrargyrum, is a heavy metal, which is an important pollutant of environment. Mercury was determined for comparision in all in nine common articles of food. In rice, mushrooms, fish, lentils, poppy seeds, soya, soya dehydrated slice and oat flakes. Mushrooms were collected in four different provinces of Czech republic. In Highlands, Central province, South Bohemia and in province of Liberec. For comparings were analyzed cultivated mushrooms, Agaricus bisporus, from supermarket. As a fish were analyzed lyofilized samples of catfish, Silurus glanis. The other articles of food were bought in supermarkets. On an atomic absorption spectometer AMA 254 (Altec, Prague, CR), was made validation of analytic method. Results: accuracy (97%), precision (3,33%), sensitivity (0,00251 l/kg), limit of detection ((LOD= 0,31 ?g/l), limit of quantification (LOQ= 1,04 ?g/l), linear dynamic range (LDR= 1,04 až 100 ?g/l) and correlation coefficient of linear part of calibration (0,9979). Measurement of all samples was done with spectometer AMA 254. By analysis of all materials was detected that increased concentration of total mercury in all occures especially in mushrooms. The highest measured value, 5,7 mg/kg, was found in a mushroom Xerocomellus chrysenteron from South Bohemia. Measured concentrations at lyofilized fish weren't important, it was only 0,04 mg/kg. In other articles of food weren't detected overlimited values. We obtained from acquired results, that the highest amount of mercury is contained in our conditions in mushrooms. According to World Health Organisation is determined that the highest tolerable concentration for articles of food is 0,5 mg/kg of mercury. In mushrooms was found after recalculation as a top limit 0,57 mg/kg of mercury. So, this result is overlimited.
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