Určení vlivu volby zkušebního organismu na výsledek stanovení toxických účinků. Porovnání výsledků stanovení akutní toxicity mikrometodou při použití 5 různých druhů sladkovodních řas (podle TNV 75 7741), vyhodnocení rozdílů v citlivosti použitých druhů, optimalizace metodických postupů.

This diploma thesis deals with a use of algal test in ecotoxicology. A freshwater algae, Desmodesmus subspicatus, was used to asses the ecotoxicity of selected chemical substances. A spectrophotometry method, of VIS spectrum, was used in evaluation of the EC50. A correlation, between a number of algal cells and the wavelength absorbance at 683 nm, has been determined for this purpose. Following chemicals were tested, 2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetic acid, (RS)-2-[4-(2-methylpropyl)phenyl]propanoic acid and N-(4-hydro-xyphenyl)acetamide. An EC50 value was determined for all these substances and also their ecotoxicity has been evaluated.

Polymers or their modifiers may become parts of a wide range of products. After the end of life cycle useful parts of the products are recycled but significant parts still become household waste. It´s therefore desirable not only by law on chemicals and chemical products, but also according to the requirements of European directive REACH, to assess the impact not only chemical but also the additives of all products or products themselves in terms of their impact on the environment. For these purposes it serves ecotoxicity tests, which allow prediction of the influence test compounds in the environment. In this diploma thesis were evaluated polypropylene modifiers, which are commercially produced. Use of ecotoxicity tests were evaluated maleic anhydride and itaconic anhydride effects on the environment. Alternative tests have been used for toxicity and namely Thamnotoxkit FTM the organism Thamnocephalus platyurus and Daphnotokit FTM the organism Daphnia magna. The phytotoxicity test groups were selected toxicity tests: Sinapis alba root growth inhibition toxicity test, Allium cepa L root growth inhibition toxicity test and Semi-chronic toxicity test on Lemna minor L. From marine toxicity tests was performed Acute inhibition test of brine shrimps Artemia salina.

This diploma thesis deals with the determination and ecotoxicological assessment of artificial sweeteners. The diploma was focused on monitoring the most commonly used sweeteners, which includes acesulfam-K, cyclamate, saccharin and sucralose. These sweeteners were analyzed by liquid chromatography with mass spectrometry, using solid phase extraction for their concentration. The samples for their determination were taken from wastewater treatment plant in Modrice. Artificial sweeteners are synthetically produced substances, which is the main reason for their occurrence in waste water. Some of them are not efficiently removed from the wastewater treatment plant and penetrate into the environment. Analysis of the samples was found, that sucralose penetrates into the environment. The ecotoxicological effect of the sweeteners was evaluated via aquatic organisms, namely on the freshwater crustaceans Thamnocephalus platyurus and Daphnia magna, on the water plant Lemna minor, and the battery of tests was supplemented by a representative of the destructors Vibrio fischeri. For all sweeteners, LC20, EC20 and IC20 values were determined. For some sweeteners, LC50, EC50 and IC50 values were also determined. During testing, saccharin represented the highest toxicity.

Background: Use of pharmaceuticals can lead to unchanged or metabolite residues in surface water that may result in negative environmental effects. Sweden has adopted the Generational goal defining direction and changes needed to become a sustainable nation, these align with the UN Sustainable Development Goals (SDGs). Sweden collects and analyzes samples for pharmaceuticals and other contaminants in surface water. Aim: To estimate risks connected to pharmaceuticals in complex mixtures, exemplified by nonsteroidal anti-inflammatory drugs (NSAIDs), and discuss how this can be used to influence the actions needed to reach the Generational goal and the SDGs of Agenda 2030. Methods: Here, measured environmental concentrations (MECs) of the NSAIDs diclofenac, ibuprofen, ketoprofen, and naproxen in Swedish surface waters and in Uppsala’s Fyris River were accessed from a database and used in conjunction with predicted no-effect concentrations (PNECs) from the literature to derive risk quotients(RQ=MEC/PNEC). For all drugs a standardized PNEC derived from OECD guideline base-set tests were found, and for diclofenac and ibuprofen also non-traditional guideline PNECs were identified. Risk cups applied by summation of MEC/PNEC-risk quotients are considered safe if the sum of RQ <1, and as proposed inSOU 2019:45, if one chemical adds more risk than 0.1 to the risk cup it would be better to substitute it for another, if possible. Results and Discussion: Standardized PNECs derived from OECD guideline base-set tests were more than 60-fold greater than non-traditional PNECs for diclofenac and ibuprofen, affecting their individual RQ contribution and total sum of RQ. Based on the non-traditional PNECs, the sum of RQ were more than or near 1 in some cases in Fyris River and elsewhere, thus indicating risk to biota especially in 2010. Diclofenac and ibuprofen typically contributed more to Risk cups than did ketoprofen and naproxen. Especially diclofenac should be considered for substitution, if possible. Swedish sales data indicate at least one more NSAID compound suitable for analysis. In addition, more than 70 pharmaceuticals were identified in Fyris River, adding to pressure on environment from NSAIDs. Risk cups are conservative and require sparse data relative to other methods, and thus can be used to prioritize further efforts. A difficulty is to find relevant ecotoxicological data for pharmaceuticals and therefore an open access database would be of value, preferably complemented with sales data for APIs. However, since a default RQ-value of 0.1 was suggested in SOU 2019:45, a lack of data would not hinder action. Use of risk cups makes it possible to work toward e.g., sustainable production practices benefiting SDG 12. Inaction after identifying a problem conflicts with SDGs 6 and 12, since it would lead to less clean water and more sanitation issues and non-sustainable consumption and production. Conclusion: Risk cups as applied here are suitable as a first tier of pharmaceutical mixture risk estimation since they are quick to perform and demand less data than other methods. Because of their dependence on PNECs, it is important to use a relevant effect test, with results preferably published in an open access database. Diclofenac’s non-traditional risk quotient indicate that the ecological status of the Fyris River is at risk, supporting the official moderate ecological status classification. This thesis suggests an additional NSAID, etoricoxib, as a possible candidate for future studies, based on the number of other NSAIDs on the market and sales numbers, pointing at the usefulness of sales data for a better understanding of risk. In addition to the NSAID group, other pharmaceuticals, active metabolites, and non-pharmaceutical chemicals add to the pressure on the environment. Data on the risk cups and risk quotients can be used as a basis for improvements at sewage treatment plants and factories as well as for launching informative campaigns to physicians and the general public, actions which all may lead to a more sustainable future.

We study the extraction of nonlinear data models in high-dimensional spaces with modified self-organizing maps. We present a general algorithm which maps low-dimensional lattices into high-dimensional data manifolds without violation of topology. The approach is based on a new principle exploiting the specific dynamical properties of the first order phase transition induced by the noise of the data. Moreover we present a second algorithm for the extraction of generalized principal curves comprising disconnected and branching manifolds. The performance of the algorithm is demonstrated for both one- and two-dimensional principal manifolds and also for the case of sparse data sets. As an application we reveal cluster structures in a set of real world data from the domain of ecotoxicology.

Microplastic particles (MPs) are widely distributed in aquatic environments and present a potential risk to marine life. This thesis considers several issues relating to methodologies for sampling and analyzing MPs and the sources and fate of these particles in the marine environment, wild and farmed shellfish, and food webs of southern coastal British Columbia, Canada. Chapter 1 introduces MPs as a contaminant, methodologies for studying them, and reviews what is known about their source, fates, and ecotoxicology in marine environments. Chapter 1 also outlines the goals of this thesis. Chapter 2 compares the potential MP concentration estimates provided by two different seawater sampling methods. Jar samples filtered to 8-µm yielded MP concentrations averaging approximately 8.5 times higher than bucket samples filtered to 63 µm, per L of water (at the site level), driven largely by differences in the number of microfibres. An analysis of MP concentrations and mesh sizes reported in the literature suggests that using a 300–350-µm mesh may underestimate total MP concentrations by one to four orders of magnitude compared with samples filtered through much smaller mesh sizes (e.g., less than 100 µm), and despite the effect of sample volume. Particles less than 300 µm in diameter make up a large component of MPs commonly found in fish and invertebrates. As such, common sampling practices fail to adequately measure a biologically relevant class of MPs, thereby undermining the ability to quantify ecological risk. Chapter 3 determines the influence of shellfish aquaculture activity, and its use of plastic equipment, on MPs in bivalves and their environment by comparing MP concentrations in Manila clams (Venerupis philippinarum) and Pacific oysters (Crassostrea gigas) grown on commercial shellfish beaches with those grown on non-aquaculture beaches from six areas. MP concentrations in water and sediment were also determined in four of the areas. MP concentrations did not differ between shellfish aquaculture and non-aquaculture sites for either bivalve species or for sediment and water samples. Beach sediment type had a minor effect, with more gravelly or sandier beaches associated with higher MP concentrations in oysters or clams, respectively. Oysters on sites using many synthetic anti-predator nets had more MPs than those on sites without any plastic, but analysis of particles using Fourier-transform infrared spectroscopy suggested a predominance of textile fibres including nylon and polyester, which are not typically used in shellfish aquaculture. Chapter 4 uses stable isotope food web analysis and hierarchical Bayesian generalized linear mixed models to explore whether bioaccumulation and biomagnification are occurring in coastal marine food webs at three locations. Bioaccumulation was higher for smaller-bodied suspension feeding animals such as bivalves. However, biomagnification was not occurring in animal digestive tracts, and trophic dilution was demonstrated in fish livers. Trophic transfer was shown to occur between prey and predator for rockfish, but higher concentrations in full stomachs compared with empty ones suggested rapid excretion of ingested MPs. Chapter 5 supplies some general conclusions on the status of MPs in the British Columbian environment, as well as risks to seafood consumers. It also explores future work that will be needed to understand the complex ecotoxicology of MPs. / Graduate / 2022-04-12

Amphibians have been facing global declines over the last decades due to direct and indirect effects of anthropogenic activities. One of the leading causes is environmental contamination, particularly that of waterbodies which are used by many amphibian species for reproduction, development, and adult life. An important source of contamination comes from agricultural runoffs of pesticides such as neonicotinoids, which are known to alter anuran survival, behaviour, predation stress response, and development. However, few studies have investigated the possible interactions between neonicotinoids and natural environmental stressors which could alter the strength and direction of observed neonicotinoid effects. This study investigated how a concentration of imidacloprid (a neonicotinoid) measured in surface waters interacted with high population density, an important environmental stressor, to influence behaviour and development across metamorphosis in wood frogs (Lithobates sylvaticus) known to breed in agricultural landscapes. I reared tadpoles in a fully crossed design experiment, between two densities (0.33 and 1 tadpole/L) and clean vs contaminated water (10 µg/L imidacloprid). Behaviours were measured in the absence and presence of predation cues using open-field tests at three distinct developmental stages, up to the metamorph stage. I found that imidacloprid did not interact with population density or independently affect behaviours in the absence of predation cues. However, individuals raised at high density compared with low density were more active at an early developmental stage but less active at metamorphic climax. Furthermore, both density and imidacloprid independently decreased the natural behavioural response (i.e., “freezing”) of tadpoles to predation cues. Both treatments also slightly accelerated metamorphosis while only density altered final mass at metamorphosis. Finally, I found that distance travelled was weakly repeatable between aquatic stages but not repeatable across metamorphosis, a pattern that was not affected by treatments. This study provides novel insights on the ecotoxicology of imidacloprid in the presence of a natural stressor, highlighting the importance of including behavioural assays and stressors in studies of amphibian ecotoxicology.

No description available.

Microplastics are present in municipal wastewater treatment plant (WWTP) effluents; however, it is unclear whether these contaminants are ingested by biota living downstream of these outfalls. This study examined whether microplastic levels in caged biota, resident fish, and environmental samples were elevated near the Waterloo and Kitchener WWTP outfalls along the Grand River in the fall of 2019. Amphipods (Hyalella azteca), fluted-shell mussels (Lasmigona costata), and rainbow trout (Oncorhynchus mykiss) were caged at one upstream reference site and two impacted sites downstream of the Kitchener WWTP for 14 (amphipods and trout) or 28 (mussels) days. Rainbow darter (Etheostoma caeruleum) were collected using a backpack electrofisher from 10 sites up and downstream of both the Kitchener and Waterloo WWTPs, along with surface water and sediment samples. Whole body Hyalella, fish digestive tracts, and fluted-shell mussel tissues (hemolymph, digestive glands, and gills) were digested in 20% potassium hydroxide. Environmental samples were processed using filtration and density separation, then visual identification of microplastics was done. Elevated particle counts were found in rainbow trout digestive tracts at the Kitchener outfall site, compared to the upstream reference and downstream farfield sites. Additionally, particle concentrations in sediment were significantly higher at the Waterloo outfall, compared to all other sites (except for one upstream location). However, whole Hyalella, fluted-shell mussel tissues (hemolymph, digestive glands, and gills), digestive tracts of rainbow darter, and surface waters did not show elevated counts downstream of these discharges. Across all samples, fibers were the most common morphology, and blue and clear particles were prevalent in samples collected near WWTPs. Overall, these findings suggest that the Kitchener and Waterloo WWTPs could be important sources of particles to the Grand River, adding to our understanding of the fate of this contaminant in freshwater ecosystems. / Thesis / Master of Science (MSc)