No abstract

Mercury is one of the important pollutants of the environment. Therefore, it’s necessary to monitor quantity of mercury especially in aquatic ecosystems. The main goal of the presented study was to compare the content of total mercury in tissues of fish coming from the Czech Republic, an important carp exporter, with focus on comparison of mercury content between 3 different ponds, its comparison between different fish species and between different tissues of the same species, and estimation whether the mercury content in tissues meets the limit given in the Commission Regulation (EC) No. 1881/2006 or not. Total mercury concentration was measured in 90 fish specimen sampled from three ponds (Velky Kocelovicky, Mysliv and Zehunsky) in autumn 2018. The values of total mercury in fish tissues was measured by atomic absorption spectrometry. The content of total mercury in the tissues decreased as follows: muscle > liver > gonads > scales. The highest average content of total mercury in muscle was 0.1517 ± 0.0176 mg/kg coming from pike caught in Velky Kocelovicky pond. In contrast, the lowest average content of total mercury in muscle 0.0036 ± 0.0003 mg/kg was found in carp tissue coming from the locality of Zehunsky pond. We confirmed that the predatory fish are more exposed to mercury than non-predatory fish. None of the monitored localities exceeded the set regulatory limit. Thus, our study shows that fish coming from these ponds are safe in terms of total mercury content.

The growing consumption of pharmaceuticals in the human population and the insufficient efficiency of their elimination in waste water has a long-term negative impact on the environment of aquatic ecosystems, including the organisms that inhabit them. A significant contributor is the consumption of anti-depressants from the SSRI group, which corresponds to their increasing concentration in the environment. The aim of this work was to determine if antidepressant sertraline is able to be stored in fish organisms and to evaluate the content of residues in various body tissues. Rainbow trout (Oncorhynchuss mykkis) was selected as the test organism and was artificially exposed to the antidepressant for 1 month (concentrations 0; 4.2; 44 and 400 ng.g-1 sertraline in the feed). Liver, kidney, brain and muscle tissue biopsies samples were taken for analysis. Detection was performed using an Accela 1250 LC pump and an Accela autosampler coupled with a high-performance mass analyzer with a heated electrospray ionization source Q-Exactive Orbitrap, operating in positive ionization mode and in PRM mode (m/z 306.08108→275.03888 and 309.009991→275.03888 for sertraline and internal standard, respectively). The limit of quantification of the method was 0.1 ng.g-1 of sertraline and the calibration curve showed a good linearity up to 20 ng.g-1. From the collected data, amount of residues was found in the liver, kidney and brain. In contrast, the incidence of residues in muscle tissue was not detected in all groups, which is favorable from the point of view of fish meat consumption, by humans.

Over the past twenty years, the prescription of antidepressant drugs has increased all over the world. After their application, antidepressants, like other pharmaceuticals, are excreted and enter the aquatic environment. They are dispersed among surface waters mainly through waste water sources, typically at very low concentrations— from a tenth up to hundreds of ng/L. Frequently detected antidepressants include fluoxetine and citalopram—both selective serotonin reuptake inhibitors. The aim of our study was to assess the embryotoxicity of fluoxetine hydrochloride and citalopram hydrochloride on the early life stages of zebrafish (Danio rerio) and the African clawed frog (Xenopus laevis). The embryos were exposed to various concentrations of the individual antidepressants and of their mixtures for 96 h. The tested levels included both environmentally relevant and higher concentrations for the evaluation of dose-dependent effects. Our study demonstrated that even environmentally relevant concentrations of these psychiatric drugs influenced zebrafish embryos, which was proven by a significant increase (p < 0.01) in the embryos’ heart rates after fluoxetine hydrochloride exposure and in their hatching rate after exposure to a combination of both antidepressants, and thus revealed a potential risk to aquatic life. Despite these results, we can conclude that the African clawed frog is more sensitive, since exposure to the highest concentrations of fluoxetine hydrochloride (10,000 μg/L) and citalopram hydrochloride (100,000 μg/L) resulted in total mortality of the frog embryos.