Job description
Topic: Occurrence of PFAS in the aquatic environment and their impact on the hygienic quality of wild fish
Supervisor – Prof. Tomáš Randák
Contact: trandak@frov.jcu.cz, +420 721 855 763
Annotation
Perfluorinated and polyfluorinated alkyl substances (PFAS) include thousands of synthetic chemicals that are highly stable and accumulate in the environment and in the bodies of organisms. Due to their properties, PFAS are used in various industrial processes, in households, and as components of pesticides. Because these compounds are resistant, they enter the environment with treated municipal or industrial wastewater. Due to their stability and also proven toxic effects, some PFAS have been included in the updated list of persistent organic pollutants of the Stockholm Convention (Stockholm Convention, 2024). In 2022, Commission Regulation (EU) 2022/2388 came into force, subsequently being incorporated into Commission Regulation (EU) 2023/915, which establishes maximum levels of specific contaminants in food. This regulation sets limit concentrations for four individual PFAS and their sum. These are perfulorooctanesulfonic acid (PFOS), perfluoroocatanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfulorohexanesulfonic acid (PFHxS). The value of the tolerable weekly intake (TWI) of the sum of limited PFAS for humans is set in Commission Regulation (EU) 2022/2388 at a level of 4.4 ng kg-1 of body weight. Humans primarily intake PFAS through food and water. In this regard, the consumption of fish, especially wild fish, is also problematic.
The main hypothesis
- PFAS concentrations in the muscle of market fish cultured in major production ponds will usually be below the hygienic limit. In fishing grounds, exceeding the hygienic limit values will be frequent in older individuals and in fish living in locations located in the lower reaches of major rivers.
- The level of PFOS contamination in the aquatic environment is increasing.
- Significant sources of PFAS contamination in the Lipno Reservoir include tributaries affected by wastewater, preparations used to treat sports equipment, ports, and shipping activities.
- PFAS concentrations in the bodies of aquatic organisms will increase with increasing level of their position in the food chain. The spectrum of contaminants will vary between individual species.
Aim(s) of the Ph.D. thesis
- To assess the load of selected sites of the aquatic environment in the Czech Republic with PFAS in terms of the presence of these substances in the muscle of various species of wild fish
- Based on the obtained results, specify sites, species, or size categories of fish that may pose a risk to fish consumers in terms of PFAS load levels.
- Based on the database results of analyses of juvenile fish, which are used as a bioindicator within the national monitoring program of aquatic environment contamination, to assess the development of PFOS contamination levels at regularly monitored sites within the Czech Republic.
- To identify the main sources of pollution of the Lipno Reservoir – a key recreational area of South Bohemia – by PFAS and analyse the distribution of these compounds in various components of the aquatic environment and in the food chain.
Possible approaches to reach the aims / to verify the hypotheses
- Sampling of fish from selected locations in the Czech Republic. Preparation of samples for analysis, analysis of samples using liquid chromatography with mass spectrometry (LC/MS).
- Historical data analyses on PFOS contamination of juvenile fish in long-term monitored locations of the Czech Republic.
- Sampling of various matrices (biota, passive samplers) of the aquatic environment of the Lipno Reservoir, and analysis of samples using LC/MS.
- Statistical analysis of data, preparation of scientific publications
References
· Buchtíková, S., Šimková, A., Rohlenová, K., Flajšhans, M., Lojek, A., Lilius, E.M., Hyršl, P., 2011. The seasonal changes in innate immunity of the common carp (Cyprinus carpio). Aquaculture 318: 169-175. doi:10.1016/j.aquaculture.2011.05.013
· Kocour, M., Gela, D., Rodina, M., & Linhart, O., 2005. Testing of performance in common carp Cyprinus carpio L. under pond husbandry conditions I: top-crossing with Northern mirror carp. Aquaculture Research 36(12): 1207–1215. doi:10.1111/j.1365-2109.2005.01340.x
· Omori, R., Adams, B., 2011. Disrupting seasonality to control disease outbreaks: The case of koi herpes virus. Journal of Theoretical Biology 271: 159-165. doi:10.1016/j.jtbi.2010.12.004
· Prchal, M., Bugeon, J., Vandeputte, M., Kause, A., Vergnet, A. Zhao, J. Gela, D., Genestout, L. Bestin, A., Haffray, P., Kocour, M., 2018. Potential for genetic improvement of the main slaughter yields in common carp with in vivo morphological predictors. Front. Genet. 9:283. doi: 10.3389/fgene.2018.00283
CENAKVA Research program
RP2 “New” pollutants in the environment and their effect on freshwater ecosystems
Activities
· Daily Ph.D. study in the discipline of Protection of Aquatic Ecosystems
· Working on student’s own Ph.D. thesis topic
· Publishing manuscripts in Q1-Q3 journals
· Presenting results at international conferences and faculty seminars, completing research internships abroad
· Teaching or assisting with courses, consulting or supervising bachelor’s or master’s students
· Supervising summer school projects
· Other activities within the given research unit
Requirements on applicants:
· Successfully completed master’s degree study in environmental chemistry, toxicology, ecology, biology, protection of environment, fishery, biology, agriculture, veterinary medicine or related fields
· Admission into the Protection of Aquatic Ecosystems Ph.D. study program at USB FFPW, full-time form of study
· General knowledge of biology, aquatic ecology and chemistry
· English language knowledge at the B1 level or higher
· User-level computer skills, particularly the MS Office suite (Word, Excel, PowerPoint, Outlook)
· Communicativeness, responsibility, conscientiousness, organizational ability, willingness to learn new things, stress resistance
We offer:
· Nice working environment in new faculty facilities
· Study and work in an international team
· Opportunities for personal and professional development
· Other benefits (5 weeks of paid leave, 4 days of sick leave, MS Office for private use)
Starting date: September 2026
Working hours: equivalent to a full-time workload (40 hours per week)
Duration of the position: 4 years (standard duration of the Ph.D. study program)
Net monthly income: from CZK 25,000 (depending on the study results)
Place of work: depending on the supervisor’s location (Vodňany)
Get in contact with the supervisor listed under the selected topic. If you reach a mutual agreement, complete the e-application to study. Applicants should submit e-application to the Ph.D. study program by May 5, 2026.
More information at:
https://www.frov.jcu.cz/en/admissions/admission-procedures
Areas of Research
- Environmental Chemistry
- Aquatic Ecology
- Fisheries & Aquaculture
