The topic of this work was based on the assessment of aquatic systems quality related to the persistent metal pollution. The use of aquatic organisms as bioindicators of metal pollution allowed the obtaining of valuable information about the acute and chronic toxicity on common Romanian aquatic species and the estimation of the environment quality. Laboratory toxicity results showed that Cd, "s, Cu, Zn, Pb, Ni, Zr, and Ti have toxic to very toxic efects on Cyprinus carpio, and this observation could raise concerns because of its importance as a ishery resource. The benthic invertebrates' analysis showed that bioaccumulation level depends on species, type of metals, and sampling sites. The metal analysis from the shells of three mollusk species showed that the metals involved in the metabolic processes (Fe, Mn, Zn, Cu, and Mg) were more accumulated than the toxic ones (Pb, Cd). The bioaccumulation factors of metals in benthic invertebrates were subunitary, which indicated a slow bioaccumulation process in the studied aquatic ecosystems. The preliminary aquatic risk assessment of Ni, Cd, Cr, Cu, Pb, "s, and Zn on C. carpio revealed insigniicant to moderate risk considering the measured environmental concentrations, acute and long-term efects and environmental compartment.Keywords: metals, ish, crustaceans, benthic invertebrates, toxicity, LC 0, M"TC, bioaccumulation, risk © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. . IntroductionMetals are constantly released in aquatic systems from natural and anthropic sources such as industrial and domestic sewage discharges, mining, farming, electronic waste, anthropic accidents, navigation traic as well as climate change events like loods (Figure ) [1, 2]. Moreover, metals are easily dissolved in water and are subsequently absorbed by aquatic organisms such as ish and invertebrates inducing a wide range of biological efects, from being essential for living organisms to being lethal, respectively. In spite of the fact that some metals are essential at low concentrations for living organisms, such as (i) micronutrients (Cu, Zn, Fe, Mn, Co, Mo, Cr, and Se) and (ii) macronutrients (Ca, Mg, Na, P, and S) at higher concentrations, they could induce toxic efects disturbing organisms' growth, metabolism, or reproduction with consequences to the entire trophic chain, including on humans [3]. In addition, the nonessential metals such as Pb, Cd, Ni, "s, and Hg enhance the overall toxic efect on organisms even at very low concentrations. ...

The aquatic environment is under increased pressure by pharmaceutically active compounds (PhACs) due to anthropogenic activities. In spite of being found at very low concentrations (ng/L to μg/L) in the environment, PhACs represent a real danger to aquatic ecosystems due to their bioaccumulation and long-term effects. In this study, the presence in the aquatic environment of six non-steroidal anti-inflammatory drugs (ibuprofen, diclofenac, acetaminophen, naproxen, indomethacin, and ketoprofen), caffeine, and carbamazepine were monitored. Moreover, their aquatic risk and ecotoxicity by three biological models were evaluated. The monitoring studies performed in Romania showed that all studied PhACs were naturally present at concentrations >0.01 μg/L, pointing out the necessity to perform further toxicity tests for environmental risk assessment. The toxicity studies were carried out on aquatic organisms or bacteria and they indicated, for most of the tested PhACs, an insignificant or low toxicity effects: lethal concentrations (LC50) on fish Cyprinus carpio ranged from 42.60 mg/L to more than 100 mg/L; effective concentrations (EC50) on planktonic crustacean Daphnia magna ranged from 11.02 mg/L to more than 100 mg/L; inhibitory concentrations (IC50)/microbial toxic concentrations (MTC) on Vibrio fischeri and other bacterial strains ranged from 7.02 mg/L to more than 100 mg/L. The PhAC aquatic risk was assessed by using the ratio between measured environmental concentration (MEC) and predicted no effect concentration (PNEC) calculated for each type of organism. The average of quotient risks (RQs) revealed that the presence of these compounds in Romania's aquatic environment induced a lower or moderate aquatic risk.

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This study, analyzes the benthic macroinvertebrates community structure and composition in order to assess the ecological status as required by the Water Framework Directive (WFD). Macroinvertebrates are the appropriate indicators to describe habitat heterogenity and the water bodies ecological status by turning the allochtone material into biomass, which is then transferred to the upper trophic levels. Moreover, the macroinvertebrates have the capacity to integrate in their structure the effects of environmental pressure at a temporal and spatial scale. In this particular case, the spatial scale is represented by the Danube Delta, Saint (St) Gheorghe Branch with a length of 112 km, carrying 22% of the Danube flow. The samples include all the organisms life cycle and were collected each month from July to October 2012. The structure and composition of macroinvertebrates were the main target of this study. Furthermore, the structural response of macroinvertebrates to environmental pressure was characterized by quantitative and qualitative analysis. Also, the ecological status was assessed by a surface water bodies methodology in accordance with WFD. This present study brings new information of the benthic community structure and dynamics, reflects the long-term effect of environmental pressure, and it is an effective tool for evaluating integrative ecological status of lotic aquatic systems.

The present paper aims to evaluate the toxic effects generated by conventional treated mine water as well as freshwater samples (Macris river) on primary producers (green algae, Selenastrum capricornutum) and primary consumers (planktonic crustaceans, Daphnia magna). Those organisms could be very realiable biological models to assess the toxic effect of mine waters on the environment. The green algae growth inhibition test (performed according to OECD201) and the acute immobilization test of freshwater crustaceans (Daphnia magna) (performed according to OECD 202) showed no growth inhibition or Daphnia magna immobilization / mortality during 72h and 48h incubation in presence of surface water samples from Macris river. The aqueous system with 1.89 g/L sulphate ion (SO4 2-) concentration, containing treated mine water mixed with freshwater sample (ratio 2.4:1), generated 100% toxic effect on crustaceans (Daphnia magna) after 48h incubation.

During the past few decades, the anthropogenic activities induced worldwide changes in the ecological systems, including the aquatic systems. This work analysed the contamination level of groundwater resources from a rural agglomeration (Central-Western part of Prahova County) by biological and physico-chemical approaches. The study was performed during the autumn of 2016 on several sampling sites (four drilling wells, depth higher than 100 m supplying three villages; two wells lower than 10 m depth and one spring). The water quality was evaluated by comparison with the limit values of the drinking water quality legislation (Law no.458/2002) and the Order 621/2014 (applicable to all groundwater bodies of Romania). The results showed that phenols and metals (iron and manganese) exceeded the threshold values in all sampling sites. Moreover, the anthropogenic factors including agriculture, use of fertilizers, manures, animal husbandry led to an increase of the bacterial load, particularly at wells sites.

Background Romania is one of the European countries reporting very high antimicrobial resistance (AMR) rates and consumption of antimicrobials. We aimed to characterize the AMR profiles and clonality of 304 multi-drug resistant (MDR) Acinetobacter baumannii (Ab) and Pseudomonas aeruginosa (Pa) strains isolated during two consecutive years (2018 and 2019) from hospital settings, hospital collecting sewage tanks and the receiving wastewater treatment plants (WWTPs) located in the main geographical regions of Romania. Methods The strains were isolated on chromogenic media and identified by MALDI-TOF-MS. Antibiotic susceptibility testing and confirmation of ESBL- and CP- producing phenotypes and genotypes were performed. The genetic characterization also included horizontal gene transfer experiments, whole-genome sequencing (WGS), assembling, annotation and characterization. Results Both clinical and aquatic isolates exhibited high MDR rates, especially the Ab strains isolated from nosocomial infections and hospital effluents. The phenotypic resistance profiles and MDR rates have largely varied by sampling point and geographic location. The highest MDR rates in the aquatic isolates were recorded in Galați WWTP, followed by Bucharest. The Ab strains harbored mostly blaOXA-23, blaOXA-24, blaSHV, blaTEM and blaGES, while Pa strains blaIMP, blaVIM, blaNDM, blaVEB, blaGES and blaTEM, with high variations depending on the geographical zone and the sampling point. The WGS analysis revealed the presence of antibiotic resistance genes (ARGs) to other antibiotic classes, such as aminoglycosides, tetracyclines, sulphonamides, fosfomycin, phenicols, trimethoprim-sulfamethoxazole as well as class 1 integrons. The molecular analyses highlighted: (i) The presence of epidemic clones such as ST2 for Ab and ST233 and ST357 for Pa; (ii) The relatedness between clinical and hospital wastewater strains and (iii) The possible dissemination of clinical Ab belonging to ST2 (also proved in the conjugation assays for blaOXA-23 or blaOXA-72 genes), ST79 and ST492 and of Pa strains belonging to ST357, ST640 and ST621 in the wastewaters. Conclusion Our study reveals the presence of CP-producing Ab and Pa in all sampling points and the clonal dissemination of clinical Ab ST2 strains in the wastewaters. The prevalent clones were correlated with the presence of class 1 integrons, suggesting that these isolates could be a significant reservoir of ARGs, being able to persist in the environment.

Benzenthonium chloride (BEC, Hyamine 1622) is a quaternary ammonium surfactant with cationic properties widely used in cleaning, sanitation, and medical products that can become harmful to humans and also to the environment. This study aimed to evaluate its acute effects on Cyprinus carpio fish in terms of oxidative stress and morphological changes on hepatic tissue in order to show the sub-lethal toxicity of BEC. Fish were exposed to 1 mg/L BEC for 24, 48, and 96 h, and the liver samples were collected. The most significant changes were noticed after 96 h of exposure when the entire antioxidant enzyme system was affected. The activities of catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase decreased by 44%, 31%, 30%, and 45%, respectively, compared to control. Glucose-6-phosphate dehydrogenase activity decreased by 29% after 96 h of control, inducing a reduction of NADPH formation which decreased by half the level of reduced glutathione, the main non-enzymatic antioxidant. These effects correlated with the raised value of lipid peroxidation after 96 h and the morphology changes on hepatic tissue, such as cytoplasmic vacuolization and nuclear hypertrophy that could affect the normal function of the liver. All of these results showed acute toxicity of BEC on C. carpio after 96 h of exposure, causing oxidative stress response at the hepatic level.