Active substances detected in surface water in Hungary today include pain and anti-inflammatory agents and antiepileptics, as wastewater treatment mechanisms cannot remove these micropollutants. The aim of our research is to detect residues of four pain-killer drugs—naproxen, nimesulide, diclofenac, and ibuprofen—and an anti-epileptic drug—carbamazepine—in water samples we collected (n = 8) from the Danube. Our samples were concentrated using solid-phase extraction and then detected with HPLC. During the evaluation, we looked for a significant difference in the concentration of the active substances. Naproxen was detectable in the largest amount in one sampling point, with an average concentration of 12,029.337 ± 1772.957 ng/L, while ibuprofen was present in the second highest concentration in another sampling site, which reached an average concentration of 4048.112 ± 2086.789 ng/L. We examined water samples taken from the same sampling sites but at different distances from the riverbank, and we found a significant difference regarding the active substance naproxen at the sampling site in Budapest District XX. The analytes were detected in varying amounts in all the water samples, so the contamination in the examined section is significant. Examining the turnover data on medicines and our results, we concluded that pharmaceutical consumption significantly contributes to the pollution of the Danube. In order to protect water quality, further research would be advisable in the field of mechanisms for wastewater treatment in order to achieve the complete removal of drug residues from wastewater.

Sweet potato (Ipomoea batatas (L.) Lam.) is increasingly recognized as a functional crop due to its rich content of health-promoting phytochemicals. This study compared the phenolic compound profiles of four sweet potato varieties differing in flesh colour (purple, orange, white, and pale yellow) cultivated in three distinct regions of Hungary. The objective was to evaluate the relative effects of pigmentation and growing location on antioxidant capacity. Tubers were collected in triplicate and analyzed spectrophotometrically (UV–Vis) for vitamin C, total flavonoids, and total polyphenols. Statistical analysis using two-way ANOVA and Tukey’s HSD revealed that flesh colour had a significant effect on all antioxidant parameters (p < 0.05), whereas geographic origin did not. Purple-fleshed tubers exhibited markedly higher levels of vitamin C (21.6 mg/100 mL), flavonoids (378.7 mg/100 mL), and polyphenols (37.0 mg/100 mL) compared with the other colour groups. These findings indicate that pigmentation is a stronger determinant of antioxidant potential than cultivation region. The results highlight the promising nutritional value of Hungarian purple-fleshed sweet potato varieties, supporting their use in functional food development and sustainable agricultural diversification strategies.