Ecotoxicological analysis of cyanotoxins and antibiotics as a threat to environmental health and exploration of statistical methods for the analysis
Year: 2021
Type: dissertation
Abstract: Environmental pollution is linked mainly to human activities as well as natural processes, therefore it is an inevitable problem that is causing a massive burden on biodiversity, ecosystems, and human health.To track and investigate contaminants that are invading the aquatic environment, "ecotoxicology" or "toxicity assessment" is a useful tool for such aims.However, ecotoxicological studies require interdisciplinary knowledge, such as ecology, toxicity, biochemistry, statistic, and so forth, thus many gaps can be mined and addressed which we can depart from fundamental studies.Considering our laboratory conditions, we first perform the ecotoxicological research to identify the detrimental abilities of emerged contaminants cyanotoxins, and emerging contaminants antibiotics to sensitive organisms zooplanktonic species which play important roles in freshwater trophic levels.Besides, to exploit efficiently obtained data as well as to encourage the essential improvements of ecotoxicological data analysis, we apply powerful and rigorous statistical methods to interpret analyzed outputs.First, I provide general information and the importance of my academic field and its connection with environmental pollution.Besides, I also declare the motivation of Ph.D. research.Second, I provide intensive reviews with a huge meta-analysis of targeted contaminants antibiotics, and cyanotoxins, such as effect mechanisms, environmental pathways, and occurrences in aquatic environments.Third, the subchronic effects of the cyanobacterial crude extracts from microcystinproducing and microcystin-free cyanobacteria, with different microcystin concentrations (1, 10, and 50 µg L -1 ) on Daphnia magna.The life-history trait responses of D. magna to cyanobacterial crude extracts were determined based on survival, reproduction, and somatic growth.In addition, the physiological response represented by the feeding rate of D. magna on green algae (Scenedesmus sp.) after exposure to both types of crude extracts was also estimated.Fourth, in the ecotoxicological context of 48-hour acute exposures, we investigate Simocephalus vetulus responses of mortality and thoracic limb rate to four fluoroquinolone antibiotics, tetracycline, and the antibiotic cocktail of those antibiotics at the concentrations of 0, 0.625, 1.25, 2.5, 5, 10, 20, and 40 mg L -1 .Fifth, the chronic toxicity test for D. magna was performed during 42 days under exposure to fluoroquinolone antibiotic ciprofloxacin and ofloxacin concentrations of 50, 500, and 5000 µg L -1 .The assessment endpoints were survival, maturity, fertility, and offspring degradations.Briefly, our studies in the PhD dissertation contribute the first and interesting results to the understanding of the toxicity of cyanotoxins and high-consumed antibiotics to sensitive organisms in aquatic environments.Besides, I am also successful in suggesting the application of rigorous statistics based on Frequentist methods for ecotoxicology.
Author: Nguyen, Tan Duc
Institution: Nagasaki University
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7146418907