Copper(II) influence on flumequine retention in soils: Macroscopic and molecular investigations

Metformin and lamotrigine sorption on a digestate amended soil in presence of trace metal contamination

The antidiabetic drug metformin and antiepileptic drug lamotrigine are contaminants of emerging concern that have been detected in biowaste-derived amendments and in the environment, and their fate must be carefully studied. This work aimed to evaluate their sorption behaviour on soil upon digestate application. Experiments were conducted on soil and digestate-amended soil as a function of time to study kinetic processes, and at equilibrium also regarding the influence of trace metals (Pb, Ni, Cr, Co, Cu, Zn) at ratio pharmaceutical/metal 1/1, 1/10, and 1/100. Pharmaceutical desorption experiments were also conducted to assess their potential mobility to groundwater. Results revealed that digestate amendment increased metformin and lamotrigine adsorbed amounts by 210% and 240%, respectively, increasing organic matter content. Metformin adsorption kinetics were best described by Langmuir model and those of lamotrigine by Elovich and intraparticle diffusion models. Trace metals did not significantly affect the adsorption of metformin in amended soil while significantly decreased that of lamotrigine by 12-39%, with exception for Cu2+ that increased both pharmaceuticals adsorbed amounts by 5 - 8%. This study highlighted the influence of digestate amendment on pharmaceutical adsorption and fate in soil, which must be considered in the circular economy scenario of waste-to-resource.

The use of copper as plant protection product contributes to environmental contamination and resulting impacts on terrestrial and aquatic biodiversity and ecosystem functions

Copper-based plant protection products (PPPs) are widely used in both conventional and organic farming, and to a lesser extent for non-agricultural maintenance of gardens, greenspaces, and infrastructures. The use of copper PPPs adds to environmental contamination by this trace element. This paper aims to review the contribution of these PPPs to the contamination of soils and waters by copper in the context of France (which can be extrapolated to most of the European countries), and the resulting impacts on terrestrial and aquatic biodiversity, as well as on ecosystem functions. It was produced in the framework of a collective scientific assessment on the impacts of PPPs on biodiversity and ecosystem services in France. Current science shows that copper, which persists in soils, can partially transfer to adjacent aquatic environments (surface water and sediment) and ultimately to the marine environment. This widespread contamination impacts biodiversity and ecosystem functions, chiefly through its effects on phototrophic and heterotrophic microbial communities, and terrestrial and aquatic invertebrates. Its effects on other biological groups and biotic interactions remain relatively under-documented.

Structure, mechanism, and toxicity in antibiotics metal complexation: Recent advances and perspectives

Antibiotic-metal complexes (AMCs) formed by antibiotics and metal ions have attracted considerable attentions in recent years. Although different removal methods for AMCs have been reported in the literature, very few investigations have focused on the mechanisms and toxic effects of antibiotic-metal coordination. This review briefly describes the structural characteristics of various commonly used antibiotics and the coordination mechanisms with metal ions. Considering the complexity of the real environment, various environmental factors affecting AMC formation are highlighted. The effects of AMCs on microbial community structure and the role of metal ions in influencing resistant genes from the molecular perspective are of interest within this work. The toxicities and mechanisms of AMCs on different species of biota are also discussed. These findings underline the need for more targeted detection and analysis methods and more suitable toxicity markers to verify the combination of antibiotics with metal ions and reveal environmental toxicities in future. This review presents an innovative idea that antibiotics combined with metal ions will change the toxicity and environmental behavior of antibiotics.

Adsorption of Individual and Mixtures of β-Blockers and Copper in Soils and Sediments

The (bio)availability of pharmaceuticals at solid/water interfaces is governed by their sorption, which determines their concentrations in groundwaters and surface waters in contact with biota, and can be affected by the presence of other contaminants such as metallic trace elements likely to compete for adsorption sites and form complexes with pharmaceuticals. We studied the adsorption of the pharmaceuticals propranolol and sotalol-two β-blockers-on one soil and one sediment using batch experiments to assess their (bio)availability. The influence of contact time, pH, and concentration was studied. As in the real environment these contaminants are not alone but in mixtures, and they were studied alone, simultaneously added, and in the presence of Cu²⁺ , which is known to form coordination complexes with propranolol and sotalol, but their presence in mixtures did not alter their adsorption properties. Sotalol was more mobile in water and thus more bioavailable for organisms than propranolol. The mobility in surface waters of both β-blockers and thus their bioavailabity for organisms is more important than their risk of transfer to groundwater during rainwater infiltration and to surface water due to runoff. Environ Toxicol Chem 2022;41:2700-2707. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Water-sediment partitioning of flumequine and florfenicol, two antibiotics used in salmon aquaculture in Chile

The water-sediment partitioning of flumequine and florfenicol, two antibiotics used in salmon aquaculture is a critical driver of their fate and environmental impact. Batch experiments, were carried out using pure water or seawater, with or without sediment, and at summer and winter temperatures of Chilean fjords. Log K_d (partition between water and sediment) of florfenicol in seawater varied from 0.62 ± 0.69 to 0.67 ± 0.13, and Log K_OC (partition between water and organic fraction of sediment) from 2.15± 0.29 to 2.19 ± 0.13. Difference between K_OC and the octanol-water partition constant (K_OW) showed that for florfenicol, adsorption onto the surface of particles was more significant than the absorption driven by hydrophobicity whilst hydrophobic absorption was a major driver of flumequine sorption. Flumequine Log K_d (0.92 ± 0.25 to 1.36 ± 0.10) and Log K_OC (from 2.44 ± 0.25 to 2.89 ± 0.10) demonstrated its greater affinity than florfenicol to particles and potential accumulation into marine sediments.

The impacts of Cu(II) complexation on gatifloxacin adsorption onto goethite and hematite

Gatifloxacin (GAT) is a new generation fluoroquinolone antibiotic and its adsorption onto iron minerals influenced by coexisting trace elements [e.g., Cu(II)] has not been well investigated. To evaluate the adsorption behavior of GAT and Cu(II) onto goethite and hematite, the complexation constants of GAT with Cu(II) were determined using potentiometric titration, and the effects of Cu(II) concentration and solution pH on GAT adsorption were investigated using batch experiments. It was observed that GAT adsorption was negatively correlated with molar concentration ratio of Cu(II) to GAT. In our experimental pH range (i.e., 3.0-10.8), the calculated main species involved in GAT adsorption were Cu(GAT^± )²⁺ and Cu(GAT^± )₂ ²⁺ under acidic to neutral conditions, and formation of Cu(GAT^- )₂ (s) facilitated the removal of GAT from solution under alkaline condition. The adsorption data were well fitted by the Freundlich model and showed high nonlinearity. In adsorption onto goethite, the primary interactions shifted from electrostatic repulsion to formation of goethite-Cu(II)-GAT ternary surface complexes with increase of GAT concentration. For hematite, electrostatic repulsion was the main inhibiting mechanism and became stronger with increase of Cu(II) concentration. Our findings suggest that it is necessary to consider the complexation between GAT and coexisting metal cations in evaluating its transport in soils rich in different iron minerals.

Influence of metal ions on sulfonamide antibiotics biochemical behavior in fiber coexisting system

Metal ions and fiber are common compounds in the livestock and poultry manure, which will affect the fate of organic compounds in aqueous environment. However, limited research has addressed the effect of coexisting metal ions and fiber on the biodegradation of sulfonamide antibiotics. Accordingly, a compositing study was performed to assess the effect of metal ions (Fe³⁺ and Cu²⁺) on the biodegradation of sulfadimethoxine sodium salt (SDM) in the presence of fiber. The enhanced adsorption of SDM onto fiber in the presence of metal ions can be attributed to the π⁺-π electron donor acceptor (EDA) interaction. The microbial (Phanerochaete chrysosprium) could easily attach onto fiber forming attached microbial, and the degradation rates of SDM of immobilized bacteria in the presence of Fe³⁺ were 100%, which were significantly higher than those of free bacteria (45%). This study indicates that Fe³⁺ and fiber could enhance the biodegradation of SDM. Fiber acts as adsorbent, carrier, and substrate which enhanced the removal of SDM.

Adsorption of Quinolone Antibiotics to Goethite under Seawater Conditions: Application of a Surface Complexation Model

The assessment of antibiotics mobility under seawater conditions has been rarely studied, as an accurate description of such multicomponent systems is quite challenging. In this study, the adsorption of a widely used quinolone antibiotic in aquaculture, Oxolinic acid (OA), to a synthetic goethite (α-FeOOH) was examined in the presence of major (e.g., Mg²⁺, SO₄^2-) and trace (e.g., Cu²⁺) ions naturally occurring in seawater. The OA adsorption can be successfully predicted using a charge distribution multisite complexation model (CD-MUSIC) coupled with the three plane model (TPM). This modeling approach allowed a quantification of the competitive and synergetic effects of different ions in seawater over a large range of environmentally relevant conditions. In addition, the transport of OA in flow-through columns can be well predicted through coupling hydrodynamic parameters and surface complexation constants obtained under seawater conditions. These results may have strong implications for assessment and prediction of the fate of quinolones in sediment-seawater interface systems.

Combining sorption experiments and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to study the adsorption of propranolol onto environmental solid matrices - Influence of copper(II)

The bioavailability of pharmaceuticals is governed by their sorption in soils/sediments, as the retention processes determine their concentration in surface- and ground-water. The adsorption of these contaminants can involve various solid components such as organic matter, clays and metallic oxides, and their distribution among these solid components depends on contaminant and solid properties. In this paper we studied the adsorption of the pharmaceutical propranolol - a beta-blocker - on eight different solids (six soils, one sediment and one kaolinite-based sample) by batch experiments. The influence of contact time, propranolol concentration and pH was considered, as well as the presence of copper(II). The investigated solids displayed a wide variability in terms of CEC (cationic exchange capacity) and organic carbon and carbonates contents. The influence of pH was negligible in the pH range from 5.5 to 8.6. The adsorbed amounts were greatly dependent on the solid and two groups of solids were evidenced: three soils of high CEC and organic carbon contents which retained high amounts of propranolol, and three soils, the sediment and the kaolinite-based sample (low CEC and organic carbon content) displaying a low adsorption capacity for the beta-blocker. A linear model enabling the determination of the sorption parameters K_d and K_oc was pertinent to describe the adsorption isotherms but the K_oc values showed a great variability. It was shown that organic carbon content alone could not explain propranolol adsorption. The CEC value was identified as influent parameter and a simple empirical model was proposed to describe propranolol adsorption. At microscopic and molecular scales, ToF-SIMS experiments indicated (i) a decrease of potassium on the surface upon propranolol adsorption with a distribution of the beta-blocker similarly to alumino-silicates, iron and organic carbon on the surface confirming a cation exchange mechanism and (ii) the absence of degradation products and copper-propranolol complexes.

Dissipation of antibiotics in three different agricultural soils after repeated application of biosolids

Application of biosolids to agricultural soils is one of the pathways by which antibiotics can be introduced into agricultural ecosystems. A pot experiment was conducted with repeated soil amendment with biosolids to examine the concentrations of four classes of antibiotics (tetracyclines, sulfonamides, fluoroquinolones, and macrolides) and their dissipation in three different soil types in wheat-rice rotations. Antibiotics accumulate in the soils after repeated application of biosolids. Fluoroquinolones showed stronger accumulation and persistence in the test soils than the other three classes of antibiotics. The maximum residual antibiotic concentration was that of norfloxacin at 155 ± 16 μg kg^-1 in the Typic Hapli-Stagnic Anthrosols (paddy soil). Predicted half-lives were up to 3.69 years, a much longer period than that between biosolid applications (twice each year on average). Antibiotic accumulation followed the rough order fluoroquinolones > tetracyclines > macrolides > sulfonamides, and the sulfonamides were seldom encountered. When biosolid application was suspended, the dissipation rate accelerated. Antibiotic dissipation was slightly slower when biosolids with high heavy metal concentrations were applied and microbial degradation may have been the main mechanism of dissipation. Norfloxacin persistence was positively correlated with its soil adsorption capacity. Cation exchange capacity and soil organic matter content may have vital roles in the soil adsorption of fluoroquinolones. Because of their persistence, the fluoroquinolones must be taken into account in the planning of biosolid applications in agricultural practice.

Adsorption and co-adsorption of diclofenac and Cu(II) on calcareous soils

Pharmaceuticals are emerging contaminants and their presence in different compartments of the environment has been detected in many countries. In this study, laboratory batch experiments were conducted to characterize the adsorption of diclofenac, a widely used non-steroidal anti-inflammatory drug, on six calcareous soils. The adsorption of diclofenac was relatively low, which may lead to a risk of groundwater contamination and plant uptake. A correlation between the soil-water distribution coefficient Kd and soil characteristics has been highlighted. Indeed, diclofenac adsorption as a function of soil organic matter content (% OM) and Rt=% CaCO3/% OM was successfully described through a simple empirical model, indicating the importance of considering the inhibiting effect of CaCO3 on OM retention properties for a better assessment of diclofenac fate in the specific case of calcareous soils. The simultaneous co-adsorption of diclofenac and copper - a ubiquitous pollutant in the environment - at the water/soil interface, was also investigated. It appeared quite unexpectedly that copper did not have a significant influence on diclofenac retention.

Adsorption of enrofloxacin in presence of Zn(II) on a calcareous soil

As a result of their consumption, excretion, disposal and persistence, antibiotics enter the soil environment and may be transported to surface and ground waters. During their transfer through soils, retention processes play a key role in their mobility. Antibiotics often coexist with heavy metals in soils due to agricultural practices and other sources of inputs. In this context, this study deals with the co-adsorption of Zn(II) and enrofloxacin (ENR), a widely-used veterinary antibiotic, on a calcareous soil using batch retention experiments and X-ray Absorption Near Edge Structure (XANES) spectroscopy. To improve our understanding of the interaction of this emerging organic contaminant with metal cations at the water-soil interface, the ternary system containing ENR, Zn(II) and a selected calcareous soil was investigated over a pH range between 7 and 10, at different solid-solution contact times and ENR concentrations. The presence of Zn(II) slightly influenced the retention of the antibiotic, leading to an increase of the adsorbed ENR amounts. The distribution coefficient Kd value increased from 0.66 Lg(-1) for single ENR adsorption to 1.04 Lg(-1) in presence of Zn(II) at a 1/2 ENR/Zn(II) ratio. The combination of adsorption isotherm data, solution speciation diagrams and XANES spectra evidenced a small proportion of Zn(II)-ENR complexes at soil pH leading to the slight increase of ENR adsorption in presence of zinc. These results suggest that it is necessary to consider the interaction between ENR and metal cations when assessing the mobility of ENR in soils.

Effects of metal cations and fulvic acid on the adsorption of ciprofloxacin onto goethite

Ciprofloxacin (CIP) can be strongly adsorbed by ferric oxides, but some influencing factors, such as multivalent cations and soil organic matter, have not been evaluated extensively. In this study, the interaction between CIP and four divalent metals (Ca, Cd, Cu, and Pb) was investigated using potentiometric titration and the results indicated that CIP can bind to the divalent metals in the following affinity order: Cu(II) > Pb(II) > Cd(II) > Ca(II). The effects of metals and fulvic acid (FA) on the adsorption behavior of CIP onto goethite surfaces were also examined using batch experiments. It was found that metal cations enhanced the CIP retention on goethite surfaces in the same order as the affinity order with CIP, indicating that metals likely increased CIP retention through cation bridging. FA was found to promote CIP sorption rather than compete with it, and the coexistence of FA and Cu(II) in the system exhibited an addictive effect with CIP sorption, indicating that they might influence the sorption separately under the studied loading condition. Taken together, our results suggested that the coexistence of divalent cations or soil organic matter will enhance CIP sorption on goethite surfaces, hence reducing its mobility and bioavailability in the environment.

Identification of soil contamination hotspots with veterinary antibiotics using heavy metal concentrations and leaching data--a field study in China

In regions with high livestock densities, the usage of antibiotics and metals for veterinary purposes or as growth promoters poses a risk in manured soils. We investigated to which degree the concentrations and depth distributions of Cu, Zn, Cr and As could be used as a tracer to discover contaminations with sulfonamides, tetracyclines and fluoroquinolones. Besides, we estimated the potential vertical translocation of antibiotics and compared the results to measured data. In the peri-urban region of Beijing, China, soil was sampled from agricultural fields and a dry riverbed contaminated by organic waste disposal. The antibiotic concentrations reached 110 μg kg(-1) sulfamethazine, 111 μg kg(-1) chlortetracycline and 62 μg kg(-1) enrofloxacin in the topsoil of agricultural fields. Intriguingly, total concentrations of Cu, Zn, Cr and As were smaller than 65, 130, 36 and 10 mg kg(-1) in surface soil, respectively, therewith fulfilling Chinese quality standards. Correlations between sulfamethazine concentrations and Cu or Zn suggest that in regions with high manure applications, one might use the frequently existing monitoring data for metals to identify potential pollution hotspots for antibiotics in topsoils. In the subsoils, we found sulfamethazine down to ≥2 m depth on agricultural sites and down to ≥4 m depth in the riverbed. As no translocation of metals was observed, subsoil antibiotic contamination could not be predicted from metal data. Nevertheless, sulfonamide stocks in the subsoil could be estimated with an accuracy of 35-200 % from fertilisation data and potential leaching rates. While this may not be sufficient for precise prediction of antibiotic exposure, it may very well be useful for the pre-identification of risk hotspots for subsequent in-depth assessment studies.

Insight into highly efficient coremoval of copper and p-nitrophenol by a newly synthesized polyamine chelating resin from aqueous media: competition and enhancement effect upon site recognition

Highly efficient coremoval of Cu(II) and p-nitrophenol (PNP) was accomplished using a newly synthesized polyamine chelating resin (CEAD) as compared to three other commercial resins. The mutual effects and inner mechanisms of their adsorption onto CEAD were systematically investigated by binary, preloading, thermodynamic, and dynamic adsorption procedures. PNP was adsorbed onto both hydrophobic and hydrophilic sites, while Cu(II) only interacted with hydrophilic amine group sites. In both preloading and binary systems, the adsorption of PNP was inhibited to the same degree by the presence of Cu(II) because of selective recognition and direct competition. On the other hand, the presence of PNP obviously enhanced the adsorption of Cu(II) by more than 7%, which was related to PNP loading on the hydrophobic surface. As proved by structural characterization, hydroxyl groups facing outward create new sites for coordination with Cu(II). Moreover, ionic strength exerted some positive influence on the properties of CEAD. Finally, more than 98% of PNP and 99% of Cu(II) could be sequentially recovered with dilute NaClO3 and HCl. These superior properties demonstrated with CEAD indicate that it could be applied to wastewaters containing both heavy metals and PNP, even for high saline aqueous media.

Macroscopic and molecular approaches of enrofloxacin retention in soils in presence of Cu(II)

The co-adsorption of copper and the fluoroquinolone antibiotic enrofloxacin (ENR) at the water-soil interface was studied by means of batch adsorption experiments, and extended X-ray absorption fine structure (EXAFS) spectroscopy. The system was investigated over a pH range between 6 and 10, at different contact times, ionic strengths, and ENR concentrations. Adsorption coefficient - Kd - was determined at relevant environmental concentrations and the value obtained in water at a ionic strength imposed by the soil and at soil natural pH was equal to 0.66Lg(-1). ENR adsorption onto the soil showed strong pH dependence illustrating the influence of the electrostatic interactions in the sorption processes. The simultaneous co-adsorption of ENR and Cu(II) on the soil was also investigated. The presence of Cu(II) strongly influenced the retention of the antibiotic, leading to an increase up to 35% of adsorbed ENR amount. The combined quantitative and spectroscopic results showed that Cu(II) and ENR directly interacted at the water-soil interface to form ternary surface complexes. Cu K-edge EXAFS data indicated a molecular structure where the carboxylate and carbonyl groups of ENR coordinate to Cu(II) to form a 6-membered chelate ring and where Cu(II) bridges between ENR and the soil surface sites. Cu(II) bonds bidentately to the surface in an inner-sphere mode. Thus, the spectroscopic data allowed us to propose the formation of ternary surface complexes with the molecular architecture soil-Cu(II)-ENR.

Effects of Cu and Ca cations and Fe/Al coating on ciprofloxacin sorption onto sand media

Emerging contaminant ciprofloxacin (CIP) has been frequently detected in soils. Its interactions with metals in soils remain largely unknown. We examined the effects of metal cations Cu and Ca and surface Fe/Al coating on CIP sorption by preloading Cu and Ca onto sand surface or mixing them with CIP in solution. Batch experiments with sand before and after removing Fe/Al coating on surface (coated and clean sand) were used. Based on Langmuir model and compared to clean sand, coated sand not only sorbed 10 times more CIP (50 mg kg(-1)) but also with 6 times stronger binding strength (1.95 L/μg). Though coated sand had limited Fe and Al on surface (157 and 904 mg kg(-1)), they were the major sites for CIP sorption probably via complexation with CIP's carboxyl group. Surface Fe/Al also played an important role in CIP sorption via Cu and Ca cation bridging as evidenced by increased CIP sorption with increasing Cu and Ca concentration preloaded onto sand surface. Different from Cu and Ca on the sand surface, Cu and Ca in solution decreased CIP sorption. Our results suggested that cations in soils could either facilitate or impede CIP sorption depending on they are on solid or solution phase.

The opposite impacts of Cu and Mg cations on dissolved organic matter-ofloxacin interaction

Dialysis equilibrium system was applied to investigate the roles of Cu(II) and Mg(II) on DOM-ofloxacin (OFL) interaction. The binding behavior of both cations and OFL were studied. The introduction of Cu(II) increased DOM-OFL interaction, while Mg(II) decreased DOM-OFL binding. Cu(II) binding to DOM was also increased by OFL, while Mg(II) binding was decreased by OFL. The change in OFL binding amount in the absence and presence of cations (ΔC(b)) was calculated and compared with cation binding (C(b)(m)). ΔC(b)/C(b)(m) was in the range of 1-3 for Cu(II) depending on the applied Cu concentration. Two ternary complexes of DOM-OFL-Cu and DOM-Cu-OFL were proposed. For Mg(II), ΔC(b)/C(b)(m) was around -1 at Mg(II) concentrations lower than 1 mM, but decreased up to -5 with increasing Mg(II) concentration. The competitive effect of Mg(II) to OFL was thus proposed. FTIR spectra were collected for mechanistic discussion.