The present paper investigated the potential of hydrodynamic cavitation (HC) as an effective tool for activating sodium percarbonate (SPC). The method's efficiency was demonstrated by effectively removing estrogens, which are pollutants that have adverse impacts on aquatic ecosystems. The effects of the SPC concentration, temperature of solution, and cavitation time were evaluated. After SPC/HC treatment, the removal of estrogens was monitored by liquid chromatography-tandem mass spectrometry (LC -MS/MS). Already after 4 s of treatment and 24 h of reaction time, more than 97% of estrogens (initial concentration of 300 ng/L) were removed. The effect of post-treatment time is not considered in several papers, even though it seems to be crucial and is discussed here. The results were supported by the values of degradation rate constants, which fit the pseudo-first-order kinetic model. We also verified that HC alone was not effective for estrogen removal under the selected conditions. The sustainability of the SPC/HC system was evaluated based on electric energy per order calculation. The combination of SPC and HC is a promising approach for rapidly degrading micropollutants such as estrogenic compounds without the need for additional technological steps, such as pH or temperature adjustment.

The production and use of manufactured chemicals have risen significantly in the last few decades. With interest in preserving and improving the state of the environment, there is also growing interested in new technologies for water purification and wastewater treatment. One frequently discussed technological group is advanced oxidation processes (AOPs). AOPs using sulphur-based radicals appear to reduce the volume of organic contaminants in wastewater significantly. The use of persulfate has excellent potential to successfully eliminate the number of emerging contaminants released into the environment. The main disadvantage of sulphur-based AOPs is the need for activation. We investigated an economically and environmentally friendly solution based on hydrodynamic cavitation, which does not require heating or additional activation of chemical substances. The method was evaluated for emerging contaminant removal research, specifically for the group of steroid estrogens. The mixture of estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2) was effectively eliminated and completely removed during a treatment that lasted just a few seconds. This novel method can be used in a broad spectrum of water treatment processes or as the intensification of reactions in chemical engineering technologies.

The fate of pharmaceuticals in the human body, from their absorption to excretion is well studied. However, medication often leaves the patient’s body in an unchanged or metabolised, yet still active, form. Diazepam and its metabolites, ranging up to 100 µg/L, have been detected in surface waters worldwide; therefore, the question of its influence on model aquatic plants, such as duckweed (Lemna minor), needs to be addressed. Lemna was cultivated in a Steinberg medium containing diazepam in three concentrations—0.2, 20, and 2000 µg/L. The activity of superoxide dismutase (SOD) and catalase (CAT), leaf count, mass, and the fluorescence quantum yield of photosynthesis were assessed. The medium was also analysed by LC-MS/MS to determine the concentration of diazepam metabolites. Our results show no negative impact of diazepam on Lemna minor, even in concentrations significantly higher than those that are ecotoxicologically relevant. On the contrary, the influence of diazepam on Lemna suggests growth stimulation and a similarity to the effect diazepam has on the human body. The comparison to the human body may be accurate because γ-Aminobutyric acid-like (GABA-like) receptors responsible for the effect in humans have also been recently described in plants. Therefore, our results can open an interesting scientific area, indicating that GABA receptors and interference with benzodiazepines are evolutionarily much older than previously anticipated. This could help to answer more questions related to the reaction of aquatic organisms to micropollutants such as psychopharmaceuticals.

Saxitoxins (STXs) are potent neurotoxins produced by marine dinoflagellates or freshwater cyanobacteria known to cause acute and eventually fatal human intoxications, which are classified as paralytic shellfish poisonings (PSPs). Rapid analysis of STXs in blood plasma can be used for a timely diagnosis and confirmation of PSPs. We developed a fast and simple method of STX extraction based on plasma sample acidification and precipitation by acetonitrile, followed by quantification using liquid chromatography-tandem mass spectrometry (LC–MS-MS). Our approach provides the results ≤30 min, with a limit of detection of 2.8 ng/mL and a lower limit of quantification of 5.0 ng/mL. Within-run and between-run precision experiments showed good reproducibility with ≤15% values. Standard curves for calibration were linear with correlation coefficients ≥0.98 across the assay calibration range (5–200 ng/mL). In an interlaboratory analytical exercise, the method was found to be 100% accurate in determining the presence or absence of STX in human plasma specimens, with recovery values of 86–99%. This simple method for STX determination in animal or human plasma can quickly and reliably diagnose STX exposures and confirm suspected PSP cases to facilitate patient treatment or expedite necessary public health or security actions.

Pharmaceutical contamination of surface water is a serious concern, posing a threat to the ecosystem stability. This study focuses on assessing the occurrence and environmental impact of diazepam and its active metabolites oxazepam, temazepam and nordazepam in two Czech rivers, identifying the main sources of pollution, and evaluating the effectiveness of root-zone wastewater treatment plant in removing these contaminants. Benzodiazepines were detected in 72% to 100% of the water samples, with oxazepam concentrations peaking at 67.50 ng/L, particularly at the conventional wastewater treatment plant effluent. While root-zone plants are often reported to be effective in removing organic pollutants, the investigated plant failed to effectively remove oxazepam, likely due to insufficient maintenance. Ecotoxicological assessments revealed that multiple sites exhibited hazard quotient values of moderate to high environmental risk, suggesting the persistence and bioaccumulative nature of these contaminants. The findings highlight the limitations of current wastewater treatment technologies in fully eliminating benzodiazepines, which continue to be detected even after treatment, leading to potential long-term ecological consequences. This research calls for the development and implementation of more effective, scalable, and cost-efficient wastewater treatment solutions to reduce pharmaceutical pollution, and for an ongoing monitoring of aquatic environments to protect freshwater resources and safeguard biodiversity.

Plastic/rubber materials used as fasteners in equipment for analyzing or removing organic pollutants in water treatment technologies form an essential part of the device. Micropollutants in water are typically present at very low concentrations (ng/L to µg/L). Therefore, when designing, for example, units for advanced oxidation processes (AOPs) or planning sample handling, it is necessary to assess whether the material is compatible with the usually hydrophobic nature of the pollutants. As a model example, the possible interactions of estrogens, namely, estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2) with six commonly used plastic and rubber materials were investigated at environmentally relevant concentrations (100–500 ng/L). In the first phase, we proved that polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and ethylene propylene diene monomer (EPDM) materials adsorbed only negligible amounts of estrogens, while significant amounts of E1, E2 and EE2 were adsorbed onto Tygon S3™ material. Another unsuitable material was styrene butadiene rubber (SBR), sorbing a considerable quantity of estrone. A detailed test of EPDM at higher concentrations (300 and 500 ng/L) and prolonged soaking time showed significant sorption of EE2 after 12 h of soaking in both deionized and tap water matrices. Thus, EPDM, PTFE and PVDF are suitable materials for sample handling or producing devices for AOP treatment due to their chemical inertness and mechanical flexibility. The results suggest that plastic materials that come into contact with contaminated water must be carefully selected, especially when working at environmentally relevant concentrations.