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Study on the Effect Factors of Microcystins、 Allelopathic Inhibition and Microcystins Prediction Model

Author: WuRong
Tutor: CuiLiFeng
School: Beijing Technology and Business University
Course: Environmental Engineering
Keywords: Microcystins effect factors allelopathic inhibition rough set MC prediction model
CLC: X52
Type: Master's thesis
Year: 2010
Downloads: 66
Quote: 0
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Abstract


Eutrophication due to produce cyanotoxin have been posed a serious hazard to drinking water. Microcystins is the most popular algae toxin. MC toxicity due to liver cancer has a role in promoting a direct impact on the safety of fish and livestock, which has caused widespread concern. Therefore it is great significance to study the impact factors of microcystin, suppression and try to put cyanotoxin predictive models for the control of pollution, to mitigate their harm to human.First, the high performance liquid chromatography (HPLC) detection and the solid phase extraction (SPE) of MC were optimized. Compared the separation, peak shape, extraction rate under different conditions, and then an highly effective and sensitive SPE-HPLC method was established. This method saves the use of drugs trifluoroacetic acid and greatly reducing the cost of MC detection because it can shorten the running time. So the method significantly reduce the cost of MC detection when it is compared with the water method of MC determination of national standards. The method also have good reproducibility、accuracy and precision.The accuracy and precision of MC-LR and MC-RR were 1.06%, 2.75% and 1.35%, 0.42% respectively. This test method is suitable for the determination of MC in the real water samples, according to the actual Yuanmingyuan water sample result of MC determination. The recoveries of MC-LR and MC-RR were 90.10% and 91.31%.The research was carried on the impact of MC produced by environmental factors (including temperature, light, initial concentration of nitrogen and phosphorus). Comparison of the number of algal density and cell relative growth rate under different settings conditions, the results showed that the optimum conditions growth of Microcystis aeruginosa are as follows: temperature of 28℃, light 3000lx, initial nitrogen and phosphorus concentrations were 1.45mg / L, 0.15mg / L(when Nitrogen and phosphorus ratio is 16:1 ). Thus, we can see the temperature, light, nitrogen and phosphorus are affected the algal growth and MC production. And higher temperature, lower light intensity is more conducive to production of MC. Nitrogen and phosphorus ratio of 16:1 is suitable for the growth of algae and MC production.Because microcystin serious harm to human health, and therefore consider the use of plant allelopathy inhibit MC generation. In this paper, the research on the use of plant Ceratophyllum demersum , Myriophyllum and the extracts from the plant culture with allelopathic. Study its allelopathy on algal growth and the impact of MC production. Determination of the process of algal density, water content of nitrogen and phosphorus content and algal toxins, after adding the plants and plant extracts. Ceratophyllum demersum, Myriophyllum live and extracts can also effectively inhibit the growth of algae and MC produced through the release of allelochemicals. The extracts from Myriophyllum had a higher allelopathic suppression. The allelopathic inhibition sensitive index RI of the algal growth and MC production is -0.844, -0.542 respectively. Algal cell structure has been damaged observed through the microscope because of inhibition by allelopathic. In addition this paper also launched the study on using the extracts from Myriophyllum to inhibite the algal growth and MC production in Yuanmingyuan actual water samples. The results showed that the Myriophyllum allelochemicals can effectively inhibit the growth of algae and MC production in Yuanmingyuan actual water samples. N-phenyl -1– Naphthylamine and Dehydroabietylamine acid acetate which is Ceratophyllum demersum may contain substances, Hydroxybenzoic acid、Catechol、3,4,5 - 3-hydroxy acid which is Myriophyllum may contain substances have some literature on algal growth apparent allelopathic inhibition by using GC-MS analysis.We can use other indicators to predict the content of MC, in view of the complexity and necessity in the actual determination. Determination of each indicator parameters and algal toxin content in the process of develop pure Microcystis. The data analyse for single-factor correlation analysis and rough set theory. We can see that the algal cells、chlorophyll-a(Chl-a)、dissolved oxygen(DO) and total nitrogen content in water(TN) have good correlation with MC. The R~2 were all more than 0.75. In the same time, the rough set analysis showed that the algal cells、Chl-a、DO and TN are the important impact of MC, the important degree are all more than 70%. In conclusion the algal cells、Chl-a、DO and TN are the main factors of MC produced.The establishment of MC predictive model is based on the comprehensive analysis of the environmental factors and the main factors of MC produced. The MC predictive model is , which combined the relationship between the algal growth and MC production as well as the algal growth model. The model is mainly suitable for MC forecast during the algae growth period. We verified the accuracy of this model by simulating the eutrophication process in the target parameters with Yuanmingyuan actual water sample. The average relative error is 10.3%, so the model is basically reasonable.

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > Water pollution and its control
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