Photodegradation of ciprofloxacin, clarithromycin and trimethoprim: influence of pH and humic acids

In view of the rising relevance of emerging pollutants in the environment, this work studies the photodegradation of three antibiotics, evaluating the effects of the pH of the medium and the concentration of dissolved organic matter. Simulated light (with a spectrum similar to that of natural sunlight) was applied to the antibiotics Ciprofloxacin (Cip), Clarithromycin (Cla) and Trimethoprim (Tri), at three different pH, and in the presence of different concentrations of humic acids. The sensitivity to light followed the sequence: Cip > Cla > Tri, which was inverse for the half-life (Tri > Cla > Cip). As the pH increased, the half-life generally decreased, except for Cla. Regarding the kinetic constant k, in the case of Cip and Tri it increased with the rise of pH, while decreased for Cla. The results corresponding to total organic carbon (TOC) indicate that the complete mineralization of the antibiotics was not achieved. The effect of humic acids was not marked, slightly increasing the degradation of Cip, and slightly decreasing it for Tri, while no effect was detected for Cla. These results may be relevant in terms of understanding the evolution of these antibiotics, especially when they reach different environmental compartments and receive sunlight radiation.Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-099574-B-C21Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-099574-B-C2

SARS-CoV-2 and other main pathogenic microorganisms in the environment: situation in Galicia and Spain

In the context of the current COVID-19 pandemic, and mostly taking a broad perspective, it is clearly relevant to study environmental factors that could affect eventual future outbreaks due to coronaviruses and/or other pathogenic microorganisms. In view of that, the authors of this manuscript review the situation of SARS-CoV-2 and other main pathogenic microorganisms in the environment, focusing on Galicia and Spain. Overall, in addition to showing local data, it is put in evidence that, summed to all efforts being carried out to treat/control this and any other eventual future epidemic diseases, both at local and global levels, a deep attention should be paid to ecological/environmental aspects that have effects on the planet, its ecosystems and their relations/associations with the probability of spreading of eventual future pandemicsThis work was supported by the Spanish Ministry of science, innovation and universities [grant numbers RTI2018-099574-B-C21 and RTI2018-099574-B-C22]. It also received funds from the European Regional Development Fund (ERDF) (FEDER in Spain), being a complement to the previous grants, without additional grant numberS

Comparison of by-products as adsorbents for the removal of the antibiotics ciprofloxacin, trimethoprim and clarithromycin

Antibiotics in the environment are considered emerging pollutants, with special relevance and concern due to the proliferation of antibiotic-resistant bacteria and genes. Therefore, finding ways to remediate antibiotics-contaminated soil and water through the use of bio-adsorbents is imperative. In this research, we investigate three by-products (hemp waste, oak ash, and mussel shell) as potential low-cost bio-adsorbents for the antibiotics Ciprofloxacin (CIP), Clarithromycin (CLA), and Trimethoprim (TRI), using batch-type and stirred flow chamber experiments to study their retention and release. The results indicate that hemp waste has higher sorption capacity for CIP and TRI (20891.8 and 2481.6 μmol L−1, respectively), while oak ash yields the highest retention for CLA (3078.4 μmol L−1). In addition, it was shown that the pH value significantly influences the sorption of these pollutants onto hemp waste. Among the three antibiotics, CLA was the most mobile, given the release experiments (903.9–1758.9 μmol kg−1), while ciprofloxacin (440.3–542.4 μmol kg−1) and trimethoprim (639.4–1652.1 μmol kg−1) are released less. Overall, the results of this research (the first of this kind including these antibiotics and sorbents simultaneously) suggest that while the individual antibiotics retention on each of the three by-products may not be entirely satisfactory, its potential combination (among them and/or with other low-cost sorbents) could significantly contribute to addressing antibiotics environmental pollution, favouring recycling and promoting a circular economy, which is a matter of global relevance.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C22Xunta de Galicia | Ref. ED431C2021/46-GCRMinisterio de Universidades | Ref. FPU19/03758Xunta de Galicia | Ref. ED481B-2022-081Agencia Estatal de Investigación | Ref. IJC2020-044197-IUniversidade de Vigo/CISU

Sorption of antibiotics in agricultural soils as a function of pH

This study aims to understand the adsorption/desorption process in six agricultural soils of two antibiotics, Ciprofloxacin (CIP) and Trimethoprim (TRI), widely used today and the influence of pH on this process. Antibiotics can reach the soil through the application of sludge and effluents from wastewater treatment plants and are directly influenced by changes in pH, once in the soil. Therefore, this study with batch experiments allows us to know the adsorption process in a pH range between 2 and 12, in six soils with different organic carbon content, between 1% and 7.7%. The results obtained show that the adsorption of CIP has its maximum at pH between 5 and 7; above and below this range, the adsorption decreases. The soils with the highest organic carbon content (between 4.4% and 7.7%) are those with the highest adsorption. The values for each forms in which the CIP molecule is found are: for K d CIP +, between 0.887 and 8.289 L kg −1 ; for K d CIP − , between 0.670 and 5.440 L kg −1 , while for K d CIP 0 , the values do not differ from 0, except soils 1 and 3, whose values are 0.206 and 0.615 L kg −1 , respectively. Regarding TRI, the maximum adsorption takes place at acidic pHs, below 6 for all soils. Above these values, desorption decreases. The K d values for each of the species vary between 0.085 and 0.218 L kg −1 for K d TRI + , between 0.011 and 0.056 L kg −1 for K d TRI 0 , and between 0.092 and 0.189 L kg −1 for K d TRI − . For both antibiotics, the highest adsorption was achieved in the soil with the highest organic carbon content (7.7%). Comparing both antibiotics, we see that CIP presents the highest adsorption, and in the case of desorption, for CIP, it varies between 3.7% and 75.8%, with the maximum desorption at basic pHs. In the case of TRI, desorption is higher, varying between 9.4% and 99.1%, with the maximum around neutrality, except for two soils, whose maximums are at pH of 4.3 and 9.5. These results should be taken into account, as once they reach the soil, pH will be a determining factor in their behaviour and fate.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C22Xunta de Galicia | Ref. ED431C2021/46-GCRXunta de Galicia | Ref. ED481B-2022-081Ministerio de Universidades | Ref. FPU19/03758Agencia Estatal de Investigación | Ref. IJC 2020-044197-

Clarithromycin as soil and environmental pollutant: Adsorption-desorption processes and influence of pH

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGAntibiotics pollution is a growing environmental issue, as high amounts of these compounds are found in soil, water and sediments. This work studies the adsorption/desorption of the macrolide antibiotic clarithromycin (CLA) for 17 agricultural soils with different edaphic characteristics. The research was carried out using batch-type experiments, with an additional assessment of the specific influence of pH for 6 of the soils. The results show that CLA adsorption reaches between 26 and 95%. In addition, the fit of the experimental data to adsorption models provided values between 1.9 and 19.7 Ln μmol1−n kg−1 for the KF, Freundlich affinity coefficient, and between 2.5 and 10.5 L kg−1 for Kd, distribution constant of Linear model. Regarding the linearity index, n, it varied between 0.56 and 1.34. Desorption showed lower scores than adsorption, with an average of 20%, and with values of 3.1 and 93.0 Ln μmol1−n kg−1 for KF(des) and 4.4 and 95.0 L kg−1 for Kd(des). The edaphic characteristics with the highest influence on adsorption were the silt fraction content and the exchangeable Ca content, while in the case of desorption, they were the total nitrogen, organic carbon, and exchangeable Ca and Mg contents. Regarding the pH, within the range studied (between 3 and 10), its value did not decisively affect the adsorption/desorption process. Overall, the set of these results could be of help to program appropriate measures leading to the retention/elimination of this antibiotic when it reaches the environment as a pollutant.Ministerio de Ciencia, Innovacción y Universidades | Ref. RTI2018-099574-B-C21Xunta de Galicia | Ref. ED431C2021/46-GCRMinisterio de Universidades | Ref. FPU19/03758Xunta de Galicia | Ref. ED481B-2022-081Ministerio de Ciencia e Innovación. | Ref. IJC2020- 044197-IUniversidade de Vigo/CISUGMinisterio de Ciencia, Innovacción y Universidades | Ref. RTI2018-099574-B-C2

SARS-CoV-2 and other main pathogenic microorganisms in the environment: situation in Galicia and Spain

In the context of the current COVID-19 pandemic, and mostly taking a broad perspective, it is clearly relevant to study environmental factors that could affect eventual future outbreaks due to coronaviruses and/or other pathogenic microorganisms. In view of that, the authors of this manuscript review the situation of SARS-CoV-2 and other main pathogenic microorganisms in the environment, focusing on Galicia and Spain. Overall, in addition to showing local data, it is put in evidence that, summed to all efforts being carried out to treat/control this and any other eventual future epidemic diseases, both at local and global levels, a deep attention should be paid to ecological/environmental aspects that have effects on the planet, its ecosystems and their relations/associations with the probability of spreading of eventual future pandemics.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C2

Efficacy of different waste and by-products from forest and food industries in the removal/retention of the antibiotic cefuroxime

Environmental pollution due to antibiotics is a serious problem. In this work, the adsorption and desorption of the antibiotic cefuroxime (CFX) were studied in four by-products/residues from the forestry and food industries. For this, batch-type experiments were carried out, adding increasing concentrations of CFX (from 0 to 50 µmol L−1) to 0.5 g of adsorbent. The materials with a pH higher than 9 (mussel shell and wood ash) were those that presented the highest adsorption percentages, from 71.2% (23.1 µmol kg−1) to 98.6% (928.0 µmol kg−1). For the rest of the adsorbents, the adsorption was also around 100% when the lowest concentrations of CFX were added, but the percentage dropped sharply when the highest dose of the antibiotic was incorporated. Adsorption data fitted well to the Langmuir and Freundlich models, with R2 greater than 0.9. Regarding desorption, the materials that presented the lowest values when the highest concentration of CFX was added were wood ash (0%) and mussel shell (2.1%), while pine bark and eucalyptus leaves presented the highest desorption (26.6% and 28.6%, respectively). Therefore, wood ash and mussel shell could be considered adsorbents with a high potential to be used in problems of environmental contamination by CFX.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C2

Sulfadiazine, sulfamethazine and sulfachloropyridazine removal using three different porous materials: pine bark, “oak ash” and mussel shell

This work focuses on studying the efficacy of three different by-products to adsorb three antibiotics (sulfadiazine, SDZ; sulfamethazine, SMT; sulfachloropyridazine, SCP). These antibiotics can be considered pollutants of the environment when they reach water, as well as in cases where they are spread on soils through irrigation or contained in sewage sludge or livestock manure. In this study, batch-type adsorption/desorption experiments were performed for each of the three sulfonamides, adding 7 different concentrations of the antibiotics, going from 1 to 50 μmol L−1, and with contact time of 24 h. The results indicate that pine bark is the most efficient bioadsorbent among those studied, as it adsorbs up to 95% of the antibiotics added, while desorption is always less than 11%. However, for “oak ash” and mussel shell the adsorption is always lower than 45 and 15%, respectively, and desorption is high, reaching up to 49% from “oak ash” and up to 81% from mussel shell. Adsorption data showed good fitting to the Linear and Freundlich models, with R2 values between 0.98 and 1.00 in both cases. Kd and KF adsorption parameters showed similar values for the same sorbent materials but were much higher for pine bark than for the other two bioadsorbents. The Freundlich's n parameter showed values in the range 0.81–1.28. The highest KF values (and therefore the highest adsorption capacities) were obtained for the antibiotic SCP in pine bark. Pine bark showed the highest capacity to adsorb each of the antibiotics, increasing as a function of the concentration added. When the concentration of sulfonamide added was 50 μM, the amounts adsorbed were 780 μmol kg−1 for SDZ, 890 μmol kg−1 for SMT, and 870 μmol kg−1 for SCP. “Oak ash” and mussel shell have low adsorption capacity for all three sulfonamides, showing values always lower than 150 μmol kg−1 (oak ash) and 20 μmol kg−1 (mussel shell) when a concentration of 50 μmol L−1 of antibiotic is added. The results of this study could aid to make an appropriate management of the by-products studied, in order to facilitate their valorization and recycling in the treatment of environmental compartments polluted with sulfonamide antibioticsThis work was supported by the Spanish Ministry of science, innovation and universities [grant numbers RTI2018-099574-B-C21 and RTI2018-099574-B-C22]. It also received funds from the European Regional Development Fund (ERDF) (FEDER in Spain), being a complement to the previous grants, without additional grant number. M. Conde-Cid holds a pre-doctoral contract (FPU15/0280, Spanish Government). The research of Dr. Gustavo F. Coelho was also supported by the Improving Coordination of Senior Staff (CAPES), Post-Doctoral Program Abroad (PDE) Process number {88881.172297/2018-01} of the Brazilian Government. The sponsors had not involvement in study design; in the collection, analyses and interpretation of data; in the writing of the report, and in the decision to submit the article for publicationS

Valorization of forest by-products as bio-adsorbents for emerging contaminants

The use of forest by-products as bio-adsorbents allows the recycling of these materials and could reduce the risks of environmental pollution due to different contaminants. This study focuses on the adsorption and release of three antibiotics (ciprofloxacin, clarithromycin and trimethoprim) on pine and oak bark materials and how pHinfluences in these processes. The results showed that the highest adsorption potential corresponds to pine bark, where the Freundlich affinity coefficient varies between 126.6 and 2979.1 Ln µmol1− n kg− 1, while, for oak bark, between 283.9 and 806.9 Ln µmol1− n kg− 1. Both bio-adsorbents show some influence of the pH affectingadsorption. Of the three antibiotics, clarithromycin was the most mobile. In general, both by-products gave satisfactory results as bio-adsorbents for the antibiotics tested. Therefore, their potential use as decontaminants could help to face environmental issues due to these emerging pollutants, reducing human and ecological risk, while contributing to a zero-waste economy.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018- 099574-B-C22Xunta de Galicia | Ref. ED431C2021/46-GCRXunta de Galicia | Ref. ED481B-2022-081Ministerio de Universidades | Ref. FPU19/03758Agencia Estatal de Investigación | Ref. IJC2020- 044426-IAgencia Estatal de Investigación | Ref. IJC2020-044197-IUniversidade de Vigo/CISU

Relevance of sorption in bio-reduction of amoxicillin taking place in forest and crop soils

The fate of antibiotics reaching soils is a matter of concern, given its potential repercussions on public health and the environment. In this work, the potential bio-reduction of the antibiotic amoxicillin (AMX), affected by sorption and desorption, is studied for 17 soils with clearly different characteristics. To carry out these studies, batch-type tests were performed, adding increasing concentrations of AMX (0, 2.5, 5, 10, 20, 30, 40, and 50 μmol L−1) to the soils. For the highest concentration added (50 μmol L−1), the adsorption values for forest soils ranged from 90.97 to 102.54 μmol kg−1 (74.21–82.41% of the amounts of antibiotic added), while the range was 69.96–94.87 μmol kg−1 (68.31–92.56%) for maize soils, and 52.72–85.40 μmol kg−1 (50.96–82.55%) for vineyard soils. When comparing the results for all soils, the highest adsorption corresponded to those more acidic and with high organic matter and non-crystalline minerals contents. The best adjustment to adsorption models corresponded to Freundlich's. AMX desorption was generally <10%; specifically, the maximum was 6.5% in forest soils, and 16.9% in agricultural soils. These results can be considered relevant since they cover agricultural and forest soils with a wide range of pH and organic matter contents, for an antibiotic that, reaching the environment as a contaminant, can pose a potential danger to human and environmental healthThis research was funded by Spanish Ministry of Science, Innovation and Universities, grant numbers RTI 2018-099574-B-C21 and RTI 2018-099574-B-C22S