Impact of municipal waste water pollution on endangered aquatic invertebrates - model group of freshwater bivalve molluscs and sertraline

Bc. Shuran Zhao

Master's thesis

Abstract:

Many concerns have been raised around pharmaceuticals due to their increasing number and concentration in the aquatic environment. Inadequately purified waste water effluent in nature reservoirs with medicine substances can directly threaten organisms living in downstream. In this work, an approach with full factorial design of non/exposed organisms based on the quantification of behavior response (the intensity of parasite attachment, spatial position of glochidia on host body, and encapsulation success) of glochidia and fish was used to investigate the effect of water-borne human pharmaceutical sertraline on early stage of freshwater mussel Unio tumidus Philipsson, 1788 (Unionida) - glochidium. We have included fish Squalius cephalus Linnaeus, 1758 (Cypriniformes) into our research for monitoring of host-parasite interaction as glochidium is an obligatory parasite on fish during larval stage. Sertraline is the most prescribed antidepressant worldwide, it belongs to Selective serotonin reuptake inhibitors (SSRIs), which are used to treat conditions such as depression or anxiety disorders. An asymmetrical exposure design was used for fish hosts and glochidia parasites at three concentrations sertraline: CONTROL (0 µg L-1) and EXPOSED (0.2 µg L-1) for fish and CONTROL (0 µg L-1), LOW-EXPOSED (0.2 µg L-1) and HIGH-EXPOSED (4 µg L-1 ) for glochidia. The results pointed that sertraline was able to affect the highly sensitive life stage of freshwater mussels and their fish host as well as their interaction. Glochidia and fish were impacted by sertraline mainly in terms of the intensity of parasite attachment to fish and resulted in more encysting on gills in comparison to the remaining body parts. The result shows the influence of chemical exposure on the whole host-parasite relationship and it was also possible to identify the effects on individual partners. On the other hand, the proved significance in both fish and glochidia cases was detected with the level of contamination moderately exceeding nature relevant concentration. The approach used in this experiment is able to identify the affected parameters and distinguish the effect of host-exposure from parasite exposure or the influence of interaction and provide a more complete result about the host-parasite interaction. Also the results indicate that the early life-stage toxicity testing is a promising and sensitive approach for testing the toxicity of pharmaceuticals or other chemicals. Glochidia and their hosts can be recommended for future studies as bioassay organisms as well as they can be used as model groups for the identification of pharmaceutical multi-species impacts in the natural water bodies.

Keywords

sertraline, SSRI, Unio tumidus, freshwater mussel, glochidium, Squalius cephalus, environmentally relevant concentrations, attachment rate, gills, fins, infestation

Language used: English

Date on which the thesis was submitted / produced: 12. 4. 2019

Thesis defence

• Supervisor: Ing. Karel Douda, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / field:
Waste Technology / Technology, Processing and Utilization of Waste