Simultaneous determination and toxicological assessment of penicillins in different water matrices

Rapid and sensitive analytical method for the determination of amoxicillin and related compounds in water meeting the requirements of the European union watch list

The presence of antibiotics in the aquatic environment is becoming one of the main research focus of scientists and policy makers. Proof of that is the inclusion of four antibiotics, amongst which is amoxicillin, in the EU Watch List (WL) (Decision 2020/1161/EU)) of substances for water monitoring. The accurate quantification of amoxicillin in water at the sub-ppb levels required by the WL is troublesome due to its physicochemical properties. In this work, the analytical challenges related to the determination of amoxicillin, and six related penicillins (ampicillin, cloxacillin, dicloxacillin, penicillin G, penicillin V and oxacillin), have been carefully addressed, including sample treatment, sample stability, chromatographic analysis and mass spectrometric detection by triple quadrupole. Given the low recoveries obtained using different solid-phase extraction cartridges, we applied the direct injection of water samples using a reversed-phase chromatographic column that allowed working with 100% aqueous mobile phase. Matrix effects were evaluated and corrected using the isotopically labelled internal standard or correction factors based on signal suppression observed in the analysis of spiked samples. The methodology developed was satisfactorily validated at 50 and 500 ng L ^- 1 for the seven penicillins studied, and it was applied to different types of water matrices, revealing the presence of ampicillin in one surface water sample and cloxacillin in three effluent wastewater samples.

Occurrence, fate and environmental risk assessment of the organic microcontaminants included in the Watch Lists set by EU Decisions 2015/495 and 2018/840 in the groundwater of Spain

This paper aims to review the existing occurrence data in Spanish groundwater (GW) for the emerging organic contaminants (EOCs) defined in the surface water Watch Lists of Decisions 2015/495/EU and 2018/840/EU since these contaminants are likely to reach GW bodies because surface waters show close interaction with GW. These two lists include 20 substances: 9 pesticides (5 neonicotinoids, 2 carbamates, 1 oxadiazole and 1 semicarbazone), 6 pharmaceuticals (diclofenac and 5 antibiotics), 3 estrogens, 1 UV filter (2-ethylhexyl-4-methoxycinnamate, EHMC) and 1 antioxidant (2,6-di-tert-butyl-4-methylphenol, BHT). Most of these substances are usually detected at low ng/L concentration range or not detected in the GW bodies of Spain. However, eventually they are reported at concentrations>100ng/L (e.g., imidacloprid, methiocarb, diclofenac, macrolide antibiotics, ciprofloxacin, EHMC and BHT). Consequently, it is required to set up drinking water standards, and/or GW threshold quality values because GW is a valuable water resource worldwide. Overall, GW is less contaminated than other water bodies, such as rivers, suggesting that aquifers possess a natural attenuation capacity and/or are less vulnerable than rivers to contamination. Nevertheless, the natural hydrogeochemical processes that control the fate and transformation of these substances during infiltration and in the aquifer have been barely investigated so far. The concentrations of the target EOCs are used to calculate hazard quotients (HQs) in the Spanish GW bodies as an estimation of their ecotoxicity and in order to compare somehow their chemical quality with respect to those of surface water. Due to the limited ecotoxicity data for most EOCs, HQs can only be calculated for few substances. The results pointed out the risk posed by the anti-inflammatory diclofenac towards Ceriodaphnia dubia (HQ=21) and the medium risk associated to the antibiotic erythromycin for Brachionus calyciflorus (HQ=0.46).

Global development of the studies focused on antibiotics in aquatic systems from 1945 to 2017

Antibiotics are used to fight diseases in humans and farm animals. Their residues, however, can enter aquatic environments and affect the resistance of non-target microbial strains, and the prevalence of antibiotic resistance genes (ARGs) potentially poses negative impacts on human health. In order to better understand how the studies of antibiotics have been conducted, we analyzed the publications on antibiotics in aquatic systems for the period of 1945-2017. We applied a bibliometric analysis method by coupling cluster analysis and network analysis. Results indicated that early research on antibiotics in water was mostly performed in America and Europe, while, in recent years, publications for the same subject were dominated by China and the USA. The majority of the articles were published in journal Chemosphere and the most representative subject categories of the seven sections were "Environmental science and ecology," "Chemistry," "Engineering," "Biochemistry and molecular biology," "Water resources," "Agriculture," and "Pharmacology and pharmacy." The most studied class of antibiotics was tetracyclines in wastewater. Antibiotic resistance, ARGs, Escherichia coli, and some mechanistic studies such as adsorption, toxicity, degradation, and kinetics were common topics in this field. ARGs present a major public health concern and much attention should be directed at the problems with antibiotics in the future studies of water.