Suchergebnisse

The worldwide population rise corroborated with the raise of the health-care standards have generated an escalation of the antibiotic production and uncontrolled usage. The subsequent effects of this escalation have led to an increase of the antibiotic resistance rates, Romania is in the top of the EU countries regarding the antibiotic resistance rates, and to a continuous presence in the environment, including the aquatic environment. Unfortunately, the present design of the classical WWTPs is not optimized for the efficient removal of antibiotics since these compounds may have highly soluble and polar molecular structures. Instead, antibiotics removal using microorganisms could be an ecofriendly solution to this environmental issue, as long as their antibiotic degradation structures are not more toxic than the antibiotic itself. In the present review, we focus on the environmental presence and biodegradation of the most commonly used antibiotics as well as on their biodegradation, based on bacterial model, monitored by mass-spectrometric methods.

A direct ion chromatographic method for the determination of chlorite, chlorate, and bromate in the presence of fluoride, chloride, nitrate, nitrite, and bromide in treated drinking waters was described. Separation of target analytes was achieved using an AS19-HC analytical column (250 mm x 4 mm), AG 19- HC guard column (50 mm x 4 mm), and KOH 25 mmol/L as mobile phase. Inorganic analytes were eluted using a flow rate of 1 mL/min. The column temperature was set up and maintained at 300C. The analyte ions
were quantified using a suppressed conductivity detector.

This study investigated the spatial and temporal distribution of nitrate and nitrite concentration in groundwater from different geographical regions, in Romania. A special emphasis was put on a descriptive statistical analysis of data, namely on the determination of seasonal indices during dry and wet seasons. Nitrate and nitrite concentrations were monitored in 24 groundwater sources situated in different areas,
between January 2016 and February 2020. The obtained data showed that the values of nitrate concentrations were situated between 8.03 mg/L in the North-Eastern part of Romania, 6.37 mg/L in the South-Eastern part of the country, and 3.55 mg/L in the
Western part towards the center of the country. Nitrite concentration values were situated under the national maximum admitted limit, 0.5 mg/L, in all the investigated areas. The obtained data shows small changes in water quality during the monitoring period, which leads to the conclusion that, in this long interval of time, there were no significant groundwater contaminations with nitrate and nitrite. For adequate control of water pollution and rigorous management of groundwater sources, seasonal indices were calculated.

Synthetic solutions of flutamide were subject to degradation using three advanced oxidation systems, namely UV/TiO2, UV/H2O2 and UV/H2O2/TiO2. Optimum conditions and degradation kinetics has been established for all three systems. The experimental results showed that all three systems can be successfully used for flutamide degradation with efficiencies higher than 99% and that advanced oxidation processes are showing
good potential for degradation of organic pollutants that cannot be suitable removed/degraded using conventional wastewater treatment processes.

Surface water contamination by synthetic dyes generates human and wildlife adverse health effects and causes photosynthesis decrease due to intense sun-light absorption of these pollutants. 50% of total discharged industrial effluents contain azo dyes. Congo Red is a benzidine based anionic azo dye that is usually employed in rubber, paper and plastic industries. Congo Red can cause eye and skin irritation and is potentially carcinogenic in nature. This study explores the development of a new HPLC method to detect synthetic dyes in residual waters coming from wastewater treatment technologies based on magnetic material adsorption. Cobalt ferrite (CoFe2O4) and chitosan-coated cobalt ferrite (CoFe2O4-Chit) prepared by a simple co-precipitation method were tested as adsorbents for Congo Red (CR). Effect of contact time, solution pH, and initial dye concentration were studied with respect to Congo Red adsorption efficiency. The adsorption experiments were performed at pH = 4.5 and 10.8. The highest value for the removal efficiency using the magnetic material of cobalt ferrite coated with chitosan (CoFe2O4-Chit) was obtained at pH 10.8.

Emerging contaminants are a heterogeneous group of chemicals that include daily personal care products and pharmaceuticals (PPCPs), flame retardants, endocrine-disrupting chemicals (EDCs) and nanoparticles (NPs) present in environment which are unregulated. In this review, we present the methods of analysis conducted by INCD-ECOIND regarding some classes of emerging contaminants (neonicotinoid pesticides, beta-blocker drugs) that are not regulated by the legislation, in different types of environmental samples (wastewater, surface water). The present review presents the selective solid-phase extraction (SPE) methods used for isolation of the targeted
compounds from aqueous matrices and also the main instrumental parameters of the separation and detection process. After extraction, the compounds were subjected to liquid phase chromatographic separation with mass spectrometric detection (UHPLC-MS/MS). Finally, the methods were applied in the determination of compounds from different categories of water, carrying out studies on the efficiency of elimination of compounds in several municipal wastewater treatment plants (WWTPs). In addition, the impact of the treatment plants on some receiving surface water used to obtain drinking water was studied.

The presence of pharmaceuticals in the aquatic ecosystem has received great attention from the scientific community in the last decades, due to their potential impact on living organisms. This paper presents a short review of the results of investigations performed by INCD-ECOIND concerning the occurrence of 32 pharmaceutical compounds belonging to important therapeutic classes and 2 disinfectants along the Danube River and its tributaries. Grab water samples were collected from multiple points along the River (10 sites) and from 2 locations for each of the tributaries Jiu, Olt and Argeș, upstream and downstream of large cities. All samples were quantified via solid phase extraction, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results of these studies show that various pharmaceutical compounds are present in the dissolved water phase of the Danube River and its tributaries in low to moderate amounts with variation due to season and location.

Injections of high volumes of samples containing hydrophobic diluents are possible in reversed-phase liquid chromatography, and in some cases an effect of peak compression can be observed. Three classes of organic compounds were studied as target compounds for peak compression: pharmaceuticals (pentoxifylline; salicylic acid; caffeine, ethylparaben); pollutants (simazine, atrazine), and natural compounds from tabacoo provenience (nicotine). Five aliphatic alcohols from butanol to octanol as hydrophobic solvents were used as sample diluent in the view of influencing the peak efficiency for the studied analytes. Among them, only pentanol, hexanol and heptanol were observed to produce peak compression resulting in a very high chromatographic efficiency for the studied compounds, while butanol and octanol allowed large volume injection with gradual decrease of the retention time of the dissolved analytes, but without their peak compression. Pentoxifylline, salicilic acid, simasine, are some examples of analytes that are characterized by sharp chromatographic peaks (high chromatographic efficiency, with over 10,000 plates/column), when high volumes of pentanol or hexanol (50 – 100 L) solutions are injected. Chromatogram monitoring was performed by UV-spectrometry detection or refractive index detection.

The retention behavior of six benzodiazepines (alprazolam, bromazepam, diazepam, flunitrazepam, medazepam, and nitrazepam) was studied using four different stationary phases, under reversed-phase mechanism in high-performance liquid chromatography. Four stationary phases were used for evaluating the retention of these compounds at fixed temperature. Functional dependences of the retention factor on the content of the organic modifier (methanol, or acetonitrile) in the composition of mobile phase were calculated. The extrapolated values of the retention factor for zero content of the organic modifier in mobile phase were higher for acetonitrile than for methanol for all studied compounds and for the four types of stationary phases.