Biotransformation and antioxidant response in Ceratophyllum demersum experimentally exposed to 1,2- and 1,4-dichlorobenzene

We report the effects of 1,2- and 1,4-dichlorobenzene (1,2-DCB and 1,4-DCB) on the aquatic macrophyte Ceratophyllum demersum. We evaluated the response of the antioxidant system through the assay of glutathione reductase (GR), guaiacol peroxidase (POD) and glutathione peroxidase (GPx). Additionally, the effect of DCBs on the detoxication system by measuring the activity of glutathione-S-transferase (GST) was evaluated.

C. demersum showed elevated GST activities when exposed to 10 and 20 mg l⁻¹ 1,2-DCB, and at 10 mg l⁻¹ for 1,4-DCB. These results show that glutathione conjugation take place at relatively high concentrations of both isomers. Significantly increased activities of POD were also detected in C. demersum exposed to concentrations above 5 mg l⁻¹ of the corresponding isomer.

The GR activity was enhanced in plants exposed to 1,2-DCB (5 mg l⁻¹) and 1,4-DCB (10 mg l⁻¹). GPx was also significantly increased in exposures to the corresponding isomer, each at a concentration of 10 mg l⁻¹. However, plants exposed to low doses of 1,4-DCB (1 mg l⁻¹) showed significantly decreased activities of both enzymes GR and GPx.

Consequently, it is clear that the exposure of the aquatic macrophyte C. demersum to DCBs is able to cause an activation of the antioxidant system, showing an isomer specific pattern, which suggests that the defence system of this plant is playing an important role in scavenging ROS, helping to protect the organism against adverse oxidative effects generated by the prooxidant action of the tested xenobiotics. Furthermore, increased GST activities give indirect evidence on the conjugation of either DCBs or the corresponding metabolites during phase II of detoxication, which supports the elimination process of toxic metabolites from cells of C. demersum.     

A system coupling hybrid biological method with UV/O<Subscript>3</Subscript> oxidation and membrane separation for treatment and reuse of industrial laundry wastewater

The possibilities of application of a three-step system combining hybrid biological treatment followed by advanced UV/O₃ oxidation with in situ generated O₃ and membrane separation (ultrafiltration (UF) and nanofiltration (NF)) to treat and reuse the wastewater from an industrial laundry are presented. By the application of a hybrid moving bed biofilm reactor (HMBBR), the total organic carbon concentration was reduced for about 90 %. However, since the HMBBR effluent still contained organic contaminants as well as high concentrations of inorganic ions and exhibited significant turbidity (8.2 NTU), its further treatment before a possible reuse in the laundry was necessary. The UV/O₃ pretreatment prior to UF was found to be an efficient method of the membrane fouling alleviation. During UF, the turbidity of wastewater was reduced below 0.3 NTU. To remove the inorganic salts, the UF permeate was further treated during NF. The NF permeate exhibited very low conductivity (27–75 μS/cm) and contained only small amounts of Ca²⁺ and Mg²⁺; thus ,it could be reused at any stage of the laundry process.     

Comparison of different modifications on QuEChERS sample preparation method for PAHs determination in black, green, red and white tea

The aim of this work was the evaluation of QuEChERS extraction method for polycyclic aromatic hydrocarbon (PAH) determination in various types of tea. In the experiment, different kinds of extraction solvents, sorbents and a final method of sample preparation were compared. The final extracts were analysed by gas chromatography-selected ion monitoring-mass spectrometry. The results suggest that acetonitrile extraction, clean up with SAX and final liquid–liquid extraction was the best combination giving the most purified extracts and acceptable compound recoveries for different types of teas. In the study of real samples, compounds belonging to light PAHs were mostly detected, and heavy polycyclic aromatic hydrocarbons, including benzo[a]pyrene, were not identified in any of samples.     

Treatment of high-ammonium anaerobic digester supernatant by aerobic granular sludge and ultrafiltration processes

Anaerobic sludge digester supernatant characterized by 569 mg TKN L^?1, high color and a COD/N ratio of 1.4 was treated in granular sequencing batch reactors (GSBRs) followed by post-denitrification (P-D) and ultrafiltration (UF) steps. The use of granular sludge allowed for the oxidation of ammonium in anaerobic digester supernatant at all investigated GSBR cycle lengths of 6, 8 and 12 h. The highest ammonium removal rate (15 mg N g^?1 VSS h^?1) with removal efficiency of 99% was noted at 8 h.Since the GSBR effluent was characterized by a high concentration of nitrites, slowly-degradable substances and biomass, additional purification steps were applied. In P-D stage, the microbial activity of granular biomass in the GSBR effluent was implemented. The P-D was supported by external carbon source addition and the most advantageous variant comprised dosing of half of the theoretical acetate dose for nitrite reduction in the 3-h intervals. The use of the system consisting of the GSBR with 8 h, an optimal P-D variant and a UF for the treatment of anaerobic digester supernatant allowed for the 99%, 71% and 97% reductions of TKN, COD and color, respectively.     

Strengthening the role of science and technology in disaster risk reduction: the Chilean strategy

This paper presents an integrative case study of Chile's national strategy of research, development, and innovation (R&D+i) for disaster resilience and progress towards developing the institutional conditions necessary for its successful implementation. The paper covers the period between 2016 and 2021, concentrating on the work of the Chilean Commission of R&D+i for Resilience to Disasters of Natural Origin (CREDEN). Through an analysis of the official records of the initiative at all of its stages, and 29 semi-structured interviews with CREDEN members and stakeholders, we aim to present a successful example of strengthening the role of science and technology in disaster risk reduction. Chile's experience is particularly interesting because its strategy focused on R&D+i and proposed developing an industry of scientific-based technological solutions for disaster resilience. The study also illustrates how strategic interaction between academia, state, and industry can be a key factor in aligning knowledge production to tackle current socio-technical challenges.     

Effects of soil amendment with PCB-contaminated sediment on the growth of two cucurbit species

Environmental Science and Pollution Research - The aim of the study was to evaluate the influence of the application of increasing proportions (0%, 10%, 25%, 50%, 75%, and 100%) of an admixture of...     

Performance change during long-term ozonation aimed at augmenting denitrification and decreasing waste activated sludge

Partial ozonation of return activated sludge for waste sludge minimization and soluble COD production was examined. Two nitrifying sequencing batch reactors, one control and one ozonated, were operated under alternating anoxic/aerobic conditions. During the first steady-state period of 95-136 d of ozonation, the amount of wasted solids decreased with the ozone dose up to 25%, generating soluble COD by cell lysis. However, during a subsequent period of 190-232 d of continuous ozonation, the effect of solids destruction and COD production decreased by 50%. The investigations of extracellular polymers content and floc shape analyses showed that, after prolonged daily ozone treatment, sludge floc structure becomes stronger, denser, and more ozone-resistant. The findings suggest that, for prolonged operation of partial sludge ozonation, an increase in ozone doses may be required to continuously maintain the expected solids destruction level. This in turn will increase the operational costs of the treatment.     

Characteristics and distribution of analyzed metals in soil profiles in the vicinity of a postflotation waste site in the Bukowno region, Poland

The lead–zinc industry in the Bukowno region of southern Poland has polluted the surface layer of the surrounding soils mainly with lead (Pb), cadmium (Cd), zinc (Zn), arsenic (As), and thallium (Tl). Analysis of six soil profiles, taken on the east side of the postflotation waste site of the Mining and Metallurgical Plants ZGH "Boles?aw" in Bukowno, showed that they were podzol soils, taking form of loose sands with neutral pH and reducing conditions. Concentration of organic matter in the horizons ranged from 2 to 80 %. The main components of the mineral soil were quartz, carbonates, K-feldspars, plagioclases, and micas (sericite). The highest total concentrations of metals were found in the O, A, and B horizons. Over 90 % of the Cd content, 80 % of the Pb content, 60 % of the Zn content, ～60 % of the Tl content, and 20 % of the As content occurred as mobile forms. The corresponding total concentrations were 10 mg/kg Cd, 922 mg/kg Pb, 694 mg/kg Zn, <1 mg/kg Tl, and <5 mg/kg As. This can potentially be taken up from the soil and transported in the trophic chain. Comparing the total metal content with the legal limits in Poland, it is observed, that the investigated soils exceeded the permissible levels of Cd, Pb, and Zn for agricultural soils. Arsenic and Tl are not reflected in the chemical quality of soil classifications.