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This paper is aimed at assessing the occurrence, fate, transport and ecological risk of ten organic UV filters in the aquatic environment of Romania. In influents, the highest concentration levels were determined for benzophenone-1 and 2,3,4-trihydroxybenzophenone with values of thousands of ng L−1 (up to 2787 and 1108 ng L−1, respectively). In the sewage sludge samples, the predominant contaminants were those with high hydrophobicity, namely benzyl salicylate, homosalate and ethylhexyl salicylate (up to 1395, 1035 and 688 ng g−1 dw, respectively). Although the removal efficiency of these organic micropollutants in the WWTPs proved to be quite high, over 60% of the UV filters monitored, some of them were also detected in effluents, in relatively high concentrations. Thus, the effluents were dominated by ethylhexyl salicylate and benzophenone-1 with concentrations up to 219 and 181 ng L−1, respectively. In surface waters, the most abundant compounds were found to be benzophenone-1, benzophenone-8 and 4-hydroxybenzophenone, with values up to 206, 108 and 159 ng L−1 respectively. On calculating the risk coefficient of the organic UV filters investigated on various aquatic species, it was observed that for fish, benzophenone-2 presents a medium risk both in effluents and in samples taken downstream of the WWTPs, while benzophenone-1 presents a high risk also in effluents as well as in surface waters taken upstream and downstream of the WWTPs. Among the salicylate derivatives, homosalate was found to present a medium risk for Daphnia magna in both effluents and samples taken downstream of the WWTPs, while ethylhexyl salicylate posed a high risk for freshwater algae in all three types of analyzed samples.

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.

The cationic surfactants have various applications being found in personal care products, detergents, cleaning products, disinfectants, hair conditioners, etc. Cationic surfactants are presented in domestic or industrial wastewater, being very resistant pollutants to biodegradation during conventional wastewater treatment (WT) methods, which generated the need to develop new efficient alternative methods. One of the alternative to conventional WT methods involves the utilization of the adsorbent nanomaterials, which are highly efficient, easy to operate, environmental friendly and cost effective. In this study, it was investigated the adsorption process of a cationic surfactant, benzyldodecyldimethylammonium bromide (benzalkonium bromide) from wastewater on magnetite nanomaterial. The adsorption investigation of benzalkonium bromide was analyzed by TOC analysis and the maximum adsorption efficiency obtained was 91.4 %. The experimental data fitted very well with Langmuir model, the correlation coefficient (R2) being 0.9792.

In this study, a new LC-MS/MS method was developed and optimized in order to detect two omnipresent additives, Bisphenol A (BPA) and Butylhydroxyanisole (BHA), in WWTP sewage sludge. Both analytes are synthetic phenolic compounds known for their endocrine disruptive and toxic properties. BPA and BHA were isolated from sludge samples using ultrasonic assisted liquid-solid extraction followed by silicagel clean-up to remove interferences, and evaporation to dryness and extract re-dissolution with 1 mL methanol prior to LC-MS analysis. All LC-MS parameters were optimized in order to obtain high sensitivity and selectivity. MS detector response was linear in the range 1 � 200 �g/L with correlation coefficient R2 ] 0.999 for both analytes. Intra-day and inter-day precision expressed as RSD values were 4.7% and 10.3% for BPA, whereas for BHA 7.8% and 13.8% RSD values were obtained. Recovery values after ultrasonic assisted extraction were 85.5% for BPA and 79.3% BHA with internal standard correction. Overall method LOQs were established at 1.97 ng/g (BPA) and 1.86 ng/g (BHA) on dry weight. Optimized chromatographic parameters allowed separation and detection of the two additives in less than 10 minutes. Both BPA and BHA were detected in all tested sludge samples with higher levels for BPA (34.6 - 132.6 ng/g), whereas BHA was found at lower levels in the range 3.16 - 5.64 ng/g.

The present study investigated the distribution and environmental fate of Bisphenol A (BPA), the 4-hydroxyacetophenone (4-HAP) metabolite, and 5 other bisphenol congeners in 2 municipal wastewater treatment plants (WWTPs) and their receiving rivers in Romania. Accordingly, a new, highly sensitive and accurate solid-phase extraction-liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed and validated. This technique generated low limit of quantitation values: below 2.3 ng/L for surface water and less than 2.4 and 2.7 ng/L for WWTP effluent and influent water. The sum of detected analytes in wastewater was between 1337 and 16 118 ng/L for influent samples and between 15 and 96 ng/L for effluent samples. In surface water, the total of all compounds was somewhere between 34 and 240 ng/L. The highest concentration observed was for BPA in all 3 types of analyzed water (up to 9140 ng/L for influent, as high as 75 ng/L for effluent, and a maximum of 135 ng/L in surface waters). All analyzed samples were free of bisphenols B, C, and F. For all analytes detected in surface water, the concentration values were higher than those determined in the effluent samples, which may be caused by intrinsic contamination of the 2 rivers (Danube and Jiu Rivers). Values of environmental risk coefficients, calculated for both effluents and surface waters, indicated a low ecological risk or no ecological risk for 3 types of organisms (algae, daphnia, and fish). Human risk assessment calculation suggests no risk to human health as a result of the presence of BPA in either of the 2 rivers. Environ Toxicol Chem 2021;40:435-446. © 2020 SETAC.

A fast and sensitive SPE-LC-MS/MS method for the determination of acrolein in environmental water samples using activated charcoal as SPE adsorbent was developed. The novelty of this study consists in acrolein extraction, separation and detection without the need of a derivatization process. Physicochemical properties of acrolein, such as low molecular weight and high polarity represent real challenges for extraction, separation, and detection of this pollutant using SPE-LC-MS/MS. These were addressed by choosing a suitable chromatographic column which ensures a good peak symmetry and retention for the analyte, as well as the choice of SPE adsorbent suitable for retaining very polar compounds like acrolein from the aqueous matrix. The chromatographic column was a Synergi Fusion RP (150 × 2.0 mm, 4.0 μm) with a C18 stationary phase modified with polar embedded amide groups. Activated charcoal adsorbent used as SPE extraction media was able to extract efficiently highly polar molecules such as acrolein and 13C3-acrylamide (internal standard) from water samples. Using this method, the obtained extraction recovery for acrolein was 88% at a 50 ng/L concentration level. Overall method quantitation limit (LOQ) for acrolein in water was established at 3.8 ng/L. The newly developed SPE-LC-MS/MS method was successfully applied to detect acrolein occurrence in wastewater and drinking water samples. Acrolein level in these samples ranged from LOQ to 122 ng/L.

The study aims to assess the trophic state of Danube River and the main tributaries in the Southern part of Romania through chlorophyll „a” (Chl a) dynamics during 2015. The samples were collected with a seasonally frequency. Several environmental variables such as water temperature, pH, salinity, dissolved oxygen, nutrients were considered. In addition, the qualitative analysis of phytoplankton community was performed. The integrative approach, which included both in-situ and laboratory analysis, highlighted positive correlation between abiotic and biotic parameters. The chlorophyll „a” dynamics showed a close dependence with the sampling sites characteristics, the point sources of pollution, phytoplankton community and specific changes of chemical parameters.

The presence of acrylamide, a potential human carcinogen, in treated drinking water has been a long-time concern for public health agencies. Due to this, acrylamide is included among the substances to be monitored in drinking water with a stated maximum admissible level of 0.1 �g/L in Europe. The necessity for ultra-trace level detection of acrylamide has led to development of an Offline-SPE-LC-MS method that involves SPE extraction of acrylamide using a strong adsorbent like activated charcoal followed by concentration. Simultaneously, a simple and rapid large volume Direct Injection LC-MS method was optimized from the previous method to detect acrylamide without the resource and time-consuming SPE step. A comprehensive comparison between the efficiency and sensitivity of the two methods is made. Optimization of LC-MS parameters (column temperature, mobile phase composition and flow, collision energy, fragmentor voltage, capillary voltage or MRM transitions) allowed high detection sensitivity. Due to Acrylamide high polarity, a Synergi Fusion-RP column with amide polar embedded groups was chosen to achieve reasonable retention and peak shape for acrylamide with a short run-time of only 3 min. The two methods provided excellent sensitivity, with reasonably low LOQ values of 2 ng/L for the Offline-SPE-LC-MS method and 30 ng/L for the Direct Injection LC-MS method. Intra-day and inter-day precision (RSD%) were 7.3 and 10.3%, for the Offline-SPE-LC-MS method and 2.4% and 6.2%, respectively for the Direct Injection LC-MS method. The analysis of acrylamide was successfully performed in drinking water from different location consumers and water treatment plants in Romania. Acrylamide was found in drinking water samples with levels between 5.2 and 35.7 ng/L using the Offline-SPE-LC-MS method. The direct injection method can only be used for acrylamide levels higher than its LOQ value (30 ng/L).