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Environmental discharge of wastewater represents a source of chemical and biological pollutants. This study firstly evaluates the microbiological and physicochemical quality of treated wastewaters collected from two wastewater treatment plants (WWTPs) located in two different Tunisian cities namely Sidi Bouzid (SB) and Gafsa (G). Then, the capacity of three raw and acid/base-activated local clays to enhance the quality of wastewaters was assessed. The results indicate that the quantities of enteric bacteria (oscillating from 1.381 × 10 3 to 1.4 × 10 8  CFU/100 mL), fungi (between 1.331 × 10 3 and 1.781 × 10 4  CFU/100 mL), as well as SARS-CoV-2 (between 4.25 × 10 3 and 5.05 × 10 5  CFU/100 mL) and Hepatitis A virus RNA (form 4.25 × 10 3 to 7.4 × 10 4  CFU/100 mL) detected in effluent wastewaters were not in compliance with the Tunisian standards for both studied WWTPs. Likewise for other indicators such as electrical conductivity (ranging 4.9-5.4 mS/cm), suspended matter (145-160 g l -1 ), chemical oxygen demand (123-160 mg l -1 ), biological oxygen demand 5 (172-195 mg l -1 ), chloride, Total Kjeldahl nitrogen (TKN) and phosphorus contents (710, 58-66 and 9.47-10.83 mg l -1 respectively), the registered values do not agree with the set standards established for wastewater treatment. On the other hand, the pH values fitted (oscillating from 6.86 (at G) to 7.24 (at SB) with the Tunisian standards for both WWTPs. After treatment, wastewaters showed better values for the microbiological parameters, especially for the clays designed as AM and HJ1, which eliminated 100% of viruses. In addition, when acid-activated AM clays were applied, a marked improvement in the quality of physicochemical parameters was obtained, especially for suspended matter (2 and 4 g l -1 for SB and G, respectively), TKN (5.2 (SB) and 6.40 (G) mg/l), phosphorus (1.01 (SB) and 0.81 (G) mg/l). Our results open perspectives for the possibility of efficiently using these specific clays in the enhancement of the quality of treated wastewaters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The primers HAV2 and HAV3 differed by a single nucleotide, representing a deletion carried by some HAV strains and were used to amplify 5′ non-coding region (5′ NCR)., (Copyright © 2023. Published by Elsevier Inc.)

The presence of pharmaceuticals in agricultural soils, like amoxicillin (AMX) and ciprofloxacin (CIP), poses a significant environmental challenge with potential implications for ecosystems and human well-being. This study explores the simultaneous adsorption of AMX and CIP on crop soils and bio-adsorbents, focusing on competitive adsorption dynamics. Tests were conducted with varying pharmaceutical concentrations in six soils and three bio-adsorbents. CIP consistently exhibited higher adsorption than AMX, particularly at higher concentrations. In the binary system, AMX's adsorption exceeded the individual system at higher concentrations, implying a synergistic effect. Bio-adsorbents, especially pine bark and oak ash, displayed superior adsorption capacities compared to soils. Some soils exhibited enhanced adsorption and retention of both antibiotics simultaneously, aligning with the cooperative adsorption model. Freundlich's adsorption model described the competitive adsorption systems well. These findings have implications for addressing antibiotic contamination in agricultural ecosystems, offering insights into complex interactions in soil environments amid rising pharmaceutical concerns., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Antibiotic consumption at high levels in both human and veterinary populations pose a risk to their eventual entry into the food chain and/or water bodies, which will adversely affect the health of living organisms. In this work, three materials from forestry and agro-food industries (pine bark, oak ash and mussel shell) were investigated as regards their potential use as bio-adsorbents in the retention of the antibiotics amoxicillin (AMX), ciprofloxacin (CIP) and trimethoprim (TMP). Batch adsorption/desorption tests were conducted, adding increasing concentrations of the pharmaceuticals individually (from 25 to 600 μmol L -1 ), reaching maximum adsorption capacities of ≈ 12000 μmol kg -1 for the three antibiotics, with removal percentages of ≈ 100% for CIP, 98-99% adsorption for TMP onto pine bark, and 98-100% adsorption for AMX onto oak ash. The presence of high calcium contents and alkaline conditions in the ash favored the formation of cationic bridges with AMX, whereas the predominance of hydrogen bonds between pine bark and TMP and CIP functional groups explain the strong affinity and retention of these antibiotics. The Freundlich's model provided the best prediction for AMX adsorption onto oak ash and mussel shell (heterogeneous adsorption), whereas the Langmuir's model described well AMX adsorption onto pine bark, as well as CIP adsorption onto oak ash (homogeneous and monolayer adsorption), while all three models provided satisfactory results for TMP. In the present study, the results obtained were crucial in terms of valorization of these adsorbents and their subsequent use to improve the retention of antibiotics of emerging concern in soils, thereby preventing contamination of waters and preserving environment quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

In view of the environmental issues caused by antibiotics, this research studies competitive adsorption/desorption for tetracycline (TC) and sulfadiazine (SDZ) in agricultural soils. Competitive adsorption was studied in binary systems (adding equal concentrations of both antibiotics). In addition, it was compared with results from simple systems. In all cases, batch-type adsorption/desorption experiments were carried out. In the binary systems, for the highest antibiotic concentration added, adsorption percentages were always higher for TC (close to 100%) than for SDZ (10-90%). In these systems, TC desorption was lower than 5% for all soils, and generally <10% for SDZ. Comparing TC and SDZ adsorption for the different systems, SDZ was clearly affected by the presence of TC, with SDZ adsorption percentages being was much higher (with differences generally above 65%) in the binary than in the simple systems. On the contrary, comparing the results of TC adsorption in simple and binary systems, TC was not affected by the presence of SDZ, obtaining similar adsorption percentages in both systems. K d and K F values (in the Linear and Freundlich models), were higher in the simple systems in the case of TC, which could be due to competition with SDZ, while for SDZ K d and K F were higher in the binary systems, with a synergistic effect of TC favoring SDZ adsorption. Regarding desorption, it reached 100% for SDZ in some soils in simple systems, dropping to 10% in the presence of TC. TC desorption was <4%, not affected by SDZ. The results indicate that environmental risks would be higher for SDZ, showing differences when both antibiotics are present. This can be considered relevant as regards public health and environmental preservation, in view of direct toxicities and the promotion of resistance to antibiotics associated with the presence of these contaminants in the environment., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Sewage sludge as agricultural amendment is the main route of human-medicine antibiotics to enter soils. When reaching environmental compartments, these compounds can cause significant risks to human and ecological health. Specifically, the antibiotic amoxicillin (AMX) is highly used in medicine, and the fact that more than 80% of the total ingested is excreted increases the chances of causing serious environmental and public health problems. As the use of low-cost bio-adsorbents could help to solve these issues, this research focuses on the retention of AMX onto four by-products of the forestry industry (eucalyptus leaf, pine bark, pine needles, and wood ash) and one from food industry (mussel shell). To carry out this study, batch-type tests were performed, where increasing concentrations of the antibiotic (0, 2.5, 5, 10, 20, 30, 40 and 50 μmol L -1 ) were added to samples of 0.5 g of each bio-adsorbent. Eucalyptus leaf, pine needle and wood ash showed adsorption scores higher than 80%, while it was up to 39% and 48% for pine bark and mussel shell, respectively. For pine bark, wood ash and mussel shell, adsorption data showed good adjustment to the Freundlich and Linear models, while pine needles and eucalyptus leaf did not fit to any model. There was not desorption when the maximum concentration of AMX (50 μmol L -1 ) was added. Overall, eucalyptus leaf, pine needles and wood ash can be considered good bio-adsorbents with high potential to retain AMX, which has significant implications regarding their eventual use to reduce risks of environmental pollution by this antibiotic., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

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 health., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2021 Elsevier Inc. All rights reserved.)

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 R 2 values between 0.98 and 1.00 in both cases. K d and K F 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 K F 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 antibiotics., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The increase of concentrations of tetracycline antibiotics in agricultural soils worldwide is of special concern, due to its potential toxic effects on soil bacterial communities. In the present work, the reuse of two waste/by-product materials as soil amendments was tested as a preventive practice for reducing tetracycline antibiotics toxicity in soils. Pine bark (PB), with high percentage of organic carbon, and crushed mussel shell (CMS), a frequent natural liming material, were added to 4 soils in doses 0, 6, 12 and 48 g of by-product per kg -1 of soil (dry weight) of each one (separately). The soils and soil-waste mixtures were then spiked with tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC). After one day of incubation, the bacterial growth was estimated in soils and soil-mixtures using the leucine incorporation technique. The addition of PB to the soils showed two different behaviors, depending on the antibiotics. The toxicity of TC and OTC decreased with the addition of PB (toxicities going from 6 to 25% and from 5 to 36%, respectively). However, CTC toxicity did not change, or even increased in response to the PB amendment. Regarding soil amendment with CMS, it was not effective to prevent the toxicity of any of the three antibiotics studied., (Copyright © 2020. Published by Elsevier Inc.)

Batch-type experiments were used to study competitive adsorption/desorption for the antibiotics tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC), onto by-products from forest and food industries (oak ash, pine bark, and mussel shell). These antibiotics are frequently present in manures and slurries spread on agrosystems. Binary competitive systems were performed by setting the dose of one antibiotic to 200 μmol L -1 , and varying the concentration of a second antibiotic from 50 to 600 μmol L -1 . In the cases where a concentration of 200 μmol L -1 was used for each antibiotic, the results of the binary experiments were also compared with those obtained in parallel tests corresponding to simple and ternary systems using the same concentration. The results indicated that pine bark can adsorb most of the antibiotics added, with desorption being less than 5% in most cases. Oak ash showed high adsorption for all three antibiotics in the simple systems (100% of CTC, 90% of TC, and 80% of OTC), but clearly decreased in the binary systems (up to values below 40%), especially for higher antibiotics concentrations, although desorption was generally less than 5%. Mussel shell showed adsorption results lesser than 25% for OTC and CT in simple systems, while increased up to 65% in binary systems in which CTC was present at high concentrations, but desorption was generally very high. CTC was the antibiotic with the highest adsorption onto all three by-products, and the one showing less decrease for its adsorption in the binary systems. Overall, the smallest differences among the various competitive systems were obtained when the adsorbent used was pine bark, and especially for the CTC antibiotic. These results could aid to develop management practices, based on the use of low-cost bio-sorbents, which would decrease risks of pollution due to tetracycline antibiotics spread in agroecosystems and affecting the environment., (Copyright © 2020 Elsevier Inc. All rights reserved.)

With the aim of obtaining information about the environmental fate and dynamics of the antibiotic doxycycline (DC) when it reaches soil, adsorption and desorption processes were studied for this compound in 20 agricultural soils, by means of batch-type and stirred-flow-chamber experiments. The results indicate that the studied soils adsorbed high amounts of DC, with adsorption percentages >91% in all cases. In addition, adsorption results were satisfactorily modeled, with good fittings to the Langmuir and Freundlich equations, with the values for Langmuir's maximum adsorption capacity (q max ) varying between 14,692 and 26,141 μmol kg -1 (average 17,816), and between 1,906 and 13,120 L n μmol 1-n kg -1 (average 6,969) for the Freundlich affinity coefficient, which are very high. The soil variables most related to the adsorption of the antibiotic were linked to organic matter (specifically, soil organic carbon-SOC- and soil nitrogen -N- contents), and to the clay fraction, as well as to cation exchange capacity, being the soils with a greater content in these variables those that presented a greater adsorption. FTIR results shown that DC adsorption mechanisms were based on interactions such as hydrogen bonds and π-π interactions between the antibiotic and soils. Desorption was very low, reaching values between 1 and 2% in batch experiments, and between 5 and 15% in stirred flow chamber experiments, which indicates a strong hysteresis affecting adsorption and desorption processes. This fact can be considered positively, as these soils could retain DC very strongly, thus reducing risks to human and ecological health., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Antibiotics spread into the environment can cause soil and water degradation. Specifically, tetracycline antibiotics (TCs) are among those most consumed in veterinary medicine, and near 90% of the doses administered to animals are excreted as original compounds, due to poor absorption. In this study we investigated competitive soil adsorption/desorption for three tetracycline antibiotics (tetracycline: TC, oxytetracycline: OTC, and chlortetracycline: CTC), usually spread on soils by slurry fertilization, affecting to soil degradation due to chemical pollution. The study was carried out on six soils selected according to their pH values (4.49-7.06), and organic matter contents (1.07-10.92%). The competitive experiments were performed in ternary systems (adding all three TCs simultaneously, using five equal and increasing concentrations, from 17 to 200 μmol L -1 ). The results were compared with those obtained in simple systems (adding individual antibiotics separately), for the same final concentration (in this case, 200 μmol L -1 ) and for different concentrations (200 μmol L -1 in the simple systems, versus 600 μmol L -1 in the ternary systems, resulting from the sum of 200 μmol L -1 of each of the three antibiotics). In all cases, batch-type adsorption/desorption experiments were carried out, with 24 h as contact time. Those soils with higher organic matter content adsorbed 100% of the TCs, with desorption being always lower than 3%. In soils with less organic matter, adsorption decreased as the dose of added antibiotic increased, due to competition for adsorption sites. CTC was the most retained among the three TCs (up to 20% more than the other when high doses of antibiotic were added). In the simple systems, percentage adsorption was always high (>85%) for the three TCs; however, percentage adsorption decreased in the ternary systems, reaching just 65% and 40% (for equal and different ionic strength, respectively) in soils with low organic matter contents. These results show the environmental and public health relevance of competition among the three TCs. In fact, the highest risk of entering the food chain takes place when these antibiotics are spread together on soils with low organic matter content, especially in the case of TC and CTC, which are the least adsorbed and the most desorbed molecules., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In this work, tetracycline (TC) adsorption and desorption were studied, and the soil properties that most influenced the process were identified. Batch experiments were carried out on 63 crop soil samples, which showed a wide range of values in their physicochemical characteristics. Adsorption curves fit well to the Freundlich equation, with K F values varying between 901 and 9202 L n μmol 1-n kg -1 . K d values ranged between 53 and 6899 L kg -1 for an initial concentration (C o ) of 400 μM, whereas the adsorption capacity (q a ) ranged from 8541 to 14,852 μmol kg -1 . TC retention on soils was high, with adsorption values always higher than 58%, and desorption values lower than 9%. Bivariate correlations and multiple linear regressions were performed to identify those soil variables having a greater influence on TC adsorption and desorption. The results indicate that organic carbon, clay, exchangeable aluminum, available phosphorus, effective cation exchange capacity content, and pH are the main characteristics affecting TC adsorption and desorption. The models, developed by means of multiple linear regression, gave satisfactory and robust predictions for TC adsorption and desorption, using easily determinable soil characteristics as input., (Copyright © 2019 Elsevier Inc. All rights reserved.)