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The significantly increasing levels of Rare Earth Elements (REEs) in seawater are largely due to multiple anthropogenic activities. Their effects on marine primary producers such as Phaeodactylum tricornutum have not been fully assessed. This study focused on examining the long-term impacts of these two commonly occurring REEs, cerium (Ce) and gadolinium (Gd), on marine diatoms by 28 d of exposure. The 72 h effective concentrations that inhibited the growth of 20% (EC20) and 50% (EC50) of the exposed population were used for long-term exposures. The growth, oxidative stress level, photosynthetic pigments, and chlorophyll fluorescence were assessed in the diatoms, after 7, 14, 21, and 28 d of REEs exposure. Results display a difference in the toxicity induced by the two elements. Exposure to 2.39 mg/L (EC20) and 3.13 mg/L (EC50) of Ce, and to 4.52 mg/L (EC20) and 6.02 mg/L (EC50) of Gd displayed a lower effect on the growth of algae cells, as the response remained below 20% for inhibition or stimulation. Except for GD, the ROS and the activities of SOD, and LPO showed, during the exposure, comparable levels respect to control cells. A change in chlorophyll levels was also observed especially under Ce exposure. Both elements showed changes in photosynthetic performance. This study provides new insights into the different effects of Ce and Gd on P. tricornutum, demonstrating their diverse modes of action on this important primary producer. The findings provide further evidence of the adverse effects of anthropogenic REEs pollution on marine ecosystems.

In recent years, sewage treatment plants did not effectively remove emerging water pollutants, leaving potential threats to human health and the environment. Advanced oxidation processes (AOPs) have emerged as a promising technology for the treatment of contaminated wastewater, and the addition of catalysts such as heavy metals has been shown to enhance their effectiveness. This review focuses on the use of rare earth elements (REEs) as catalysts in the AOP process for the degradation of organic pollutants. Cerium and La are the most studied REEs, and their mechanism of action is based on the oxygen vacancies and REE ion concentration in the catalysts. Metal oxide surfaces improve the decomposition of hydrogen peroxide to form hydroxide species, which degrade the organics. The review discusses the targets of AOPs, including pharmaceuticals, dyes, and other molecules such as alkaloids, herbicides, and phenols. The current state-of-the-art advances of REEs-based AOPs, including Fenton-like oxidation and photocatalytic oxidation, are also discussed, with an emphasis on their catalytic performance and mechanism. Additionally, factors affecting water chemistry, such as pH, temperature, dissolved oxygen, inorganic species, and natural organic matter, are analyzed. REEs have great potential for enhancing the removal of dangerous organics from aqueous solutions, and further research is needed to explore the photoFenton-like activity of REEs and their ideal implementation for wastewater treatment.

Irbesartan belongs to the Sartan family, whose members are used in the treatment of arterial hypertension and kidney disease among patients with hypertension and type 2 diabetes mellitus as part of a treatment based on antihypertensive drugs. This drug has reached surface waters, accumulating to the extent of being considered an emerging pollutant, along with other substances from the same class. Wastewater treatment plants, which constitute the main environmental source of this compound, fail to completely reduce its presence in wastewater and generate additional toxic byproducts through the chlorine-based disinfection process. This study provides a comprehensive investigation into the chlorination mechanisms of irbesartan, revealing the identity of twelve new byproducts, which were characterized using NMR and mass spectrometry (MS-TOF). The other six byproducts were published in a previous study, allowing for the confirmation of some aspects of the supposed mechanisms of degradation, along with the identification of those that had only been hypothesized. An ecotoxicological assessment of a mixture and isolated byproducts was performed using Raphidocelis subcapitata for algal growth inhibition, Daphnia magna for immobility, and Aliivibrio fischeri for luminescence inhibition. The results revealed the variable toxicity of irbesartan and its byproducts. Different organisms exhibited varying sensitivities to the byproducts, with Aliivibrio fischeri being the most sensitive. The coexistence of multiple byproducts in the environment, their high toxicity, and their potential interactions highlight the significant environmental risks associated with chlorination and its derivates. Our study highlights the ongoing debate surrounding the generation of disinfection byproducts.

The increasing use and demand of rare earth elements in many emerging technologies is leading to a potentially higher input to the marine environment. This study compared for the first time the effect of lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), dysprosium (Dy), and erbium (Er) to the microalga Phaeodactylum tricornutum Bohlin. The algal growth inhibition was investigated after 72 h of exposure. The median effect concentrations (EC50) ranged from 0.98 mg/L to 13.21 mg/L and elements were ranked as follows: Gd > Ce > Er > La > Eu > Nd > Dy > Sm. The comparison of predicted no effect concentrations (PNEC) for hazard and risk assessment with measured environmental concentrations showed that ecological risks deriving from REEs could be present, but limited to specific environments like estuarine waters. The results support evidence of actions to manage the REE impact in seawater environments, looking to improve the monitoring tailored to the different and dynamic nature of ecosystems.

Buffelgrass (Cenchrus ciliaris L.) is an invasive C4 perennial grass species that substantially reduces native plant diversity of the Sonoran Desert through fire promotion and resource competition. Broad-spectrum herbicides are essentially used for its control, but they have a negative environmental and ecological impact. Recently, phytotoxicity on C. ciliaris has been discovered for two metabolites produced in vitro by the phytopathogenic fungi Cochliobolus australiensis and Pyricularia grisea. They were identified as (10S,11S)-(—)-epi-pyriculol and radicinin and resulted in being potential candidates for the development of bioherbicides for buffelgrass biocontrol. They have already shown promising results, but their ecotoxicological profiles and degradability have been poorly investigated. In this study, ecotoxicological tests against representative organisms from aquatic ecosystems (Aliivibrio fischeri bacterium, Raphidocelis subcapitata alga, and Daphnia magna crustacean) revealed relatively low toxicity for these compounds, supporting further studies for their practical application. The stability of these metabolites in International Organization for Standardization (ISO) 8692:2012 culture medium under different temperatures and light conditions was also evaluated, revealing that 98.90% of radicinin degraded after 3 days in sunlight. Significant degradation percentages (59.51–73.82%) were also obtained at room temperature, 30 °C or under ultraviolet (254 nm) light exposure. On the other hand, (10S,11S)-epi-pyriculol showed more stability under all the aforementioned conditions (49.26–65.32%). The sunlight treatment was also shown to be most effective for the degradation of this metabolite. These results suggest that radicinin could provide rapid degradability when used in agrochemical formulations, whereas (10S,11S)-epi-pyriculol stands as a notably more stable compound.

Octocrylene is an organic sunscreen whose main action is to absorb UVB radiation and short UVA wavelengths; it is used in various cosmetic products in order to provide an adequate sun-protection factor or to protect the cosmetic formulations themselves from UV radiation. This filter is believed to be a possible endocrine disruptor and is also questioned due to its allergic and/or photoallergic potential. However, it continues to be widely used, and it has been found in various environments, not least those of swimming pools, where it is evidently released by consumers, to the point that it is now considered an emerging micropollutant. The present investigation presents the possible chemical fate of octocrylene in the typical chlorination conditions of wastewater or swimming pools. A total of 11 disinfection byproducts were identified, and 6 were identified for the first time, and separated by HPLC. These products were identified through careful mass spectrometry studies and 1D and 2D NMR experiments. A formation mechanism has been proposed that justifies the chemical structures of all of the compounds identified. The ecotoxicological assessment of octocrylene and their products was carried out by employing Phaeodactylum tricornutum, Brachionus plicatilis and Aliivibrio fischeri as bioindicators. The ecotoxicity results reveal that toxic byproducts might be generated during the oxidation process, increasing the potential risk to the marine environment.

In recent years, many studies have reported the frequent detection of antihypertensive agents such as sartans (olmesartan, valsartan, irbesartan and candesartan) in the influents and effluents of wastewater treatment plants (WWTPs) and in the superficial waters of rivers and lakes in both Europe and North America. In this paper, the degradation pathway for candesartan (CAN) was investigated by simulating the chlorination process that is normally used to reduce microbial contamination in a WWTP. Twelve isolated degradation byproducts (DPs), four of which were isolated for the first time, were separated on a C-18 column by employing a gradient HPLC method, and their structures were identified by combining nuclear magnetic resonance and mass spectrometry and comparing the results with commercial standards. On the basis of these results, a mechanism of formation starting from the parent drug is proposed. The ecotoxicity of CAN and its DPs was studied by conducting a battery of ecotoxicity tests; bioassays were performed using Aliivibrio fischeri (bacterium), Daphnia magna (planktonic crustacean) and Raphidocelis subcapitata (alga). The ecotoxicity results shed new light on the increased toxicity of DPs compared with the parent compound.

Antihypertensive drugs are among the most prescribed drugs. Olmesartan acid, of the sartan class, belongs to a relatively new generation of antihypertensive drugs called angiotensin II receptor blockers. There are very few studies on the presence and fate of sartans in the environment, despite them being marketed in huge quantities, metabolized in low percentages, and detected in wastewater and water bodies. This paper presents a study on the less abundant and more polar fractions that have been neglected in previous studies, which led to the isolation by chromatographic methods of thirteen degradation byproducts (DPs), six of which are new, identified by nuclear magnetic resonance and mass spectrometry. A mechanism of degradation from the parent drug was proposed. The ecotoxicity of olmesartan acid and identified compounds was evaluated in Aliivibrio fischeri bacteria and Raphidocelis subcapitata algae to assess acute and chronic toxicity. For 75% of the DPs, acute and chronic exposure to the compounds, at concentrations of 5 mg/L, inhibited population growth in the algae and decreased bioluminescence in the bacteria.

The discovery of various sartans, which are among the most used antihypertensive drugs in the world, is increasingly frequent not only in wastewater but also in surface water and, in some cases, even in drinking or groundwater. In this paper, the degradation pathway of olmesartan acid, one of the most used sartans, was investigated by simulating the chlorination process normally used in a wastewater treatment plant to reduce similar emerging pollutants. The structures of nine isolated degradation byproducts (DPs), eight of which were isolated for the first time, were separated via chromatography column and HPLC methods, identified by combining nuclear magnetic resonance and mass spectrometry, and justified by a proposed mechanism of formation beginning from the parent drug. Ecotoxicity tests on olmesartan acid and its nine DPs showed that 50% of the investigated byproducts inhibited the target species Aliivibrio fischeri and Raphidocelis subcapitata, causing functional decreases of 18% and 53%, respectively.

In recent years, many studies have highlighted the consistent finding of amoxicillin in waters destined for wastewater treatment plants, in addition to superficial waters of rivers and lakes in both Europe and North America. In this paper, the amoxicillin degradation pathway was investigated by simulating the chlorination process normally used in a wastewater treatment plant to reduce similar emerging pollutants at three different pH values. The structures of 16 isolated degradation byproducts (DPs), one of which was isolated for the first time, were separated on a C-18 column via a gradient HPLC method. Combining mass spectrometry and nuclear magnetic resonance, we then compared commercial standards and justified a proposed formation mechanism beginning from the parent drug. Microbial growth inhibition bioassays with Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were performed to determine the potential loss of antibacterial activity in isolated degradation byproducts. An increase of antibacterial activity in the DPs was observed compared to the parent compound.