Phytotoxicity and degradation of antibiotic ofloxacin in duckweed (Spirodela polyrhiza) system

Ofloxacin weakened treatment performance of rural domestic sewage in an aerobic biofilm system by affecting biofilm resistance, bacterial community, and functional genes

Ofloxacin (OFL) is a typical fluoroquinolone antibiotic widely detected in rural domestic sewage, however, its effects on the performance of aerobic biofilm systems during sewage treatment process remain poorly understood. We carried out an aerobic biofilm experiment to explore how the OFL with different concentrations affects the pollutant removal efficiency of rural domestic sewage. Results demonstrated that the OFL negatively affected pollutant removal in aerobic biofilm systems. High OFL levels resulted in a decrease in removal efficiency: 9.33% for chemical oxygen demand (COD), 18.57% for ammonium (NH4+-N), and 8.49% for total phosphorus (TP) after 35 days. The findings related to the chemical and biological properties of the biofilm revealed that the OFL exposure triggered oxidative stress and SOS responses, decreased the live cell number and extracellular polymeric substance content of biofilm, and altered bacterial community composition. More specifically, the relative abundance of key genera linked to COD (e.g., Rhodobacter), NH4+-N (e.g., Nitrosomonas), and TP (e.g., Dechlorimonas) removal was decreased. Such the OFL-induced decrease of these genera might result in the down-regulation of carbon degradation (amyA), ammonia oxidation (hao), and phosphorus adsorption (ppx) functional genes. The conventional pollutants (COD, NH4+-N, and TP) removal was directly affected by biofilm resistance, functional genes, and bacterial community under OFL exposure, and the bacterial community played a more dominant role based on partial least-squares path model analysis. These findings will provide valuable insights into understanding how antibiotics impact the performance of aerobic biofilm systems during rural domestic sewage treatment.

Futuristic advancements in phytoremediation of endocrine disruptor Bisphenol A: A step towards sustainable pollutant degradation for rehabilitated environment

Bisphenol A (BPA) accumulates in the environment at lethal concentrations because of its high production rate and utilization. BPA, originating from industrial effluent, plastic production, and consumer products, poses serious risks to both the environment and human health. The widespread aggregation of BPA leads to endocrine disruption, reactive oxygen species-mediated DNA damage, epigenetic modifications and carcinogenicity, which can disturb the normal homeostasis of the body. The living being in a population is subjected to BPA exposure via air, water and food. Globally, urinary analysis reports have shown higher BPA concentrations in all age groups, with children being particularly susceptible due to its occurrence in items such as milk bottles. The conventional methods are costly with a low removal rate. Since there is no proper eco-friendly and cost-effective degradation of BPA reported so far. The phytoremediation, green-biotechnology based method which is a cost-effective and renewable resource can be used to sequestrate BPA. Phytoremediation is observed in numerous plant species with different mechanisms to remove harmful contaminants. Plants normally undergo several improvements in genetic and molecular levels to withstand stress and lower levels of toxicants. But such natural adaptation requires more time and also higher concentration of contaminants may disrupt the normal growth, survival and yield of the plants. Therefore, natural or synthetic amendments and genetic modifications can improve the xenobiotics removal rate by the plants. Also, constructed wetlands technique utilizes the plant's phytoremediation mechanisms to remove industrial effluents and medical residues. In this review, we have discussed the limitations and futuristic advancement strategies for degrading BPA using phytoremediation-associated mechanisms.

Antibiotics soil-solution chemistry: A review of environmental behavior and uptake and transformation by plants

The increased use of antibiotics by humans for various purposes has left the environment polluted. Antibiotic pollution remediation is challenging because antibiotics exist in trace amounts and only highly sensitive detection techniques could be used to quantify them. Nevertheless, their trace quantity is not a hindrance to their transfer along the food chain, causing sensitization and the development of antibiotic resistance. Despite an increase in the literature on antibiotic pollution and the development and transfer of antibiotic-resistant genes (ARGs), little attention has been given to the behavior of antibiotics at the soil-solution interface and how this affects antibiotic adsorption-desorption interactions and subsequent uptake and transformation by plants. Thus, this review critically examines the interactions and possible degradation mechanisms of antibiotics in soil and the link between antibiotic soil-solution chemistry and uptake by plants. Also, different factors influencing antibiotic mobility in soil and the transfer of ARGs from one organism to another were considered. The mechanistic and critical analyses revealed that: (a) the charge characteristics of antibiotics at the soil-root interface determine whether they are adsorbed to soil or taken up by plants; (b) antibiotics that avoid soil colloids and reach soil pore water can be absorbed by plant roots, but their translocation to the stem and leaves depends on the ionic state of the molecule; (c) few studies have explored how plants adapt to antibiotic pollution and the transformation of antibiotics in plants; and (d) the persistence of antibiotics in cropland soils can be influenced by the content of soil organic matter, coexisting ions, and fertilization practices. Future research should focus on the soil/solution-antibiotic-plant interactions to reveal detailed mechanisms of antibiotic transformation by plants and whether plant-transformed antibiotics could be of environmental risk.

The interactions between aquatic plants and antibiotics: Progress and prospects

Antibiotics have emerged as a widespread pollutant in the aquatic environment. Aquatic phytoremediation to remove antibiotic pollution in water has aroused increasing research. Due to complex interaction between aquatic plants and antibiotics in the aquatic environment, it is essential to summarize the present research progress and point out the shortcomings to better use aquatic plants to remediate antibiotic pollution. A growing body of evidence indicates roots are the most important tissues for aquatic plants to absorb and accumulate antibiotics and antibiotics can be transferred in aquatic plants. LogKow value is an important factor to affecting the antibiotic absorption by aquatic plant. The study showed that antibiotics have toxic effects on aquatic plants, including metabolic interference, oxidative damage, damage to photosynthetic system, and inhibition of growth. However, the species sensitivity distribution model indicated that the general environmental concentrations of antibiotics pose no risk to aquatic plant growth. Aquatic plants can significantly reduce the antibiotics concentration in water and the removal efficiency is affected by many factors, such as the type of aquatic plants and antibiotics. Macrolide antibiotics are most easily removed by plants. This study reviewed the current research progress and provides valuable scientific recommendations for further research.

Effects of dissolved organic matter, pH and nutrient on ciprofloxacin bioaccumulation and toxicity in duckweed

Water pollution induced by antibiotics has garnered considerable concern, necessitating urgent and effective removal methods. This study focused on exploring ciprofloxacin (CIP) removal by duckweed and assessing CIP bioaccumulation and toxic effects within duckweed under varying dissolved organic matter categories, pH levels, and nutrient (nitrogen (N) and phosphorus (P)) levels. The results revealed the proficient and rapid elimination of CIP from water by duckweed, resulting in 86.17 % to 92.82 % removal efficiency at the end of the 7-day experiment. Across all exposure groups, varying degrees of CIP bioaccumulation in duckweed were evident, with uptake established as a primary pathway for CIP elimination within this plant. Additionally, five CIP metabolites were identified in duckweed tissues. Interestingly, the presence of humic acid (HA) and fulvic acid (FA) reduced CIP absorption by duckweed, with FA yielding a more pronounced impact. Optimal CIP removal was recorded at a pH of 7.5, while duckweed displayed heightened physiological stress induced by CIP at pH 8.5. Although the influence of N and P concentrations on CIP removal by duckweed was modest, excessive N and P levels intensified the physiological strain of CIP on duckweed.

Phytoremediation for antibiotics removal from aqueous solutions: A meta-analysis

Antibiotics are widely used as drugs and enter water bodies through various routes, leading to environmental pollution. As a green in-situ remediation technology, phytoremediation has been proven to be highly effective in removing antibiotics present in the aqueous phase. However, these data are distributed in various studies and lack systematic analysis, which could provide a more comprehensive understanding of the current status and trends in the research field. Based on this, a meta-analysis was conducted from three perspectives in this study: the factors influencing antibiotics removal by phytoremediation, the effect of antibiotics on plant physiological indexes, and the accumulation and translocation of antibiotics in plants. The results showed that plants have a significant effect on antibiotics removal, which is influenced by plant species, running time, biomass, antibiotic types and antibiotic concentration. Although some physiological indexes of plants changed under stress from high antibiotic concentrations, most plant species demonstrated resistance to antibiotic concentrations below 100 μgL-1. Additionally, the amount of antibiotics accumulated in plants was extremely little, so the risk of secondary pollution was minimal during phytoremediation. The results of this study reveal the main factors influencing antibiotics removal by phytoremediation and plant physiological responses to antibiotics, providing a reference for improving the rational application of phytoremediation for antibiotics removal. In addition, it will provide concepts and directions for improving the efficiency of sustainable and environmentally friendly remediation methods for treating antibiotic pollution.

Impact of pharmaceutical industry wastewater on stress physiological responses of Spirodela polyrhiza (L.) Schleiden

Impact of pharmaceutical wastewater collected from aeration tank on aquatic macrophyte Spirodela polyrhiza (L.) Schleiden was studied in the present study. Various plant parameters such as chlorophyll, protein, and proline content of wastewater-exposed plants were examined to determine the toxic impacts of pharmaceutical wastewater. In addition to these parameters, electrolyte leakage (EL) and catalase (CAT) activities in S. polyrhiza were assessed for each day of exposure to the wastewater. S. polyrhiza was exposed to four different wastewater concentrations (25%, 50%, 75%, and 100%) under laboratory conditions for 7 days. The plants experienced severe toxicity as revealed by the reduction in photosynthetic pigments, increase in electrolyte leakage, and enhancement of antioxidant enzyme (CAT) activity in S. polyrhiza with an increase in concentration and time of exposure to pharmaceutical effluent.

Occurrence, Bioaccumulation, Metabolism and Ecotoxicity of Fluoroquinolones in the Aquatic Environment: A Review

In recent years, there has been growing concern about antibiotic contamination in water bodies, particularly the widespread presence of fluoroquinolones (FQs), which pose a serious threat to ecosystems due to their extensive use and the phenomenon of "pseudo-persistence". This article provides a comprehensive review of the literature on FQs in water bodies, summarizing and analyzing contamination levels of FQs in global surface water over the past three years, as well as the bioaccumulation and metabolism patterns of FQs in aquatic organisms, their ecological toxicity, and the influencing factors. The results show that FQs contamination is widespread in surface water across the surveyed 32 countries, with ciprofloxacin and norfloxacin being the most heavy contaminants. Furthermore, contamination levels are generally higher in developing and developed countries. It has been observed that compound types, species, and environmental factors influence the bioaccumulation, metabolism, and toxicity of FQs in aquatic organisms. FQs tend to accumulate more in organisms with higher lipid content, and toxicity experiments have shown that FQs exhibit the highest toxicity to bacteria and the weakest toxicity to mollusk. This article summarizes and analyzes the current research status and shortcomings of FQs, providing guidance and theoretical support for future research directions.

Four antibiotics and copper interactive effects on the growth and physiological characteristics of Hydrilla verticillata (L.f.) Royle

Co-pollution of antibiotics and heavy metal copper (Cu) is common in freshwater environments because of their wide use as antimicrobial agents, especially in aquaculture. However, the toxic effects of coexisting antibiotics and heavy metals on aquatic plants remain unclear. This study investigated the effect of four antibiotics (i.e., enrofloxacin, ENR; tetracycline, TC; sulfamethoxazole, SMX; erythromycin, ERY), Cu, and their mixture on the growth and physiological responses of Hydrilla verticillata (L.f.) Royle. Results showed that the four antibiotics exhibited toxic effects on the growth and physiological indicators of H. verticillata, and root elongation was the most sensitive endpoint of the phytotoxicity test. The median effect concentration (EC50) of root elongation indicated that TC (EC50 = 10.05 mg/L) has the highest level of growth toxicity, and the toxicity of ENR to aquatic plants was close to TC (EC50 = 10.44 mg/L), followed by SMX (EC50 = 20.08 mg/L). However, there was no significant toxic effect of 20 mg/L ERY on the root elongation. Hydrophobicity may be a key factor affecting the phytotoxicity of antibiotics. Moreover, antagonistic toxic effects were observed under ENR + Cu, TC + Cu, SMX + Cu, and ERY + Cu co-exposures at all the experimental concentrations (0.01-20 mg/L). Due to the concentrations of antibiotics in natural waters usually with ng/L levels, our results suggested that environmental antibiotic concentrations probably pose low ecological risk to aquatic plants and indicated the H. verticillata could be used as phytoremediation candidate to remove antibiotic or antibiotic-Cu pollutions in general nature water.

Effect of Fenton process as a pretreatment in the phytoremediation of metronidazole by Scirpus lacustris

AbstractThe present study evaluated the effect of the Fenton process as pretreatment for metronidazole (MNZ) removal coupled with a phytoremediation system using Scirpus lacustris as macrophyte. Initial concentrations of 0.5, 5, 10, 15, and 20 mg MNZ/L were studied in batch cultures. Results obtained in the MNZ removal by phytoremediation showed efficiencies of 93 ± 2%, 81 ± 4%, 85 ± 1%, 84 ± 2%, and 87 ± 6%, respectively. The metronidazole pretreated by the Fenton process and subsequently fed to the phytoremediation system increased the removal efficiencies up to 93 ± 3%, 99 ± 1%, 99 ± 4%, 94 ± 2%, and 94 ± 3%, respectively. Individual studies with Scirpus lacustris in touch with metronidazole displayed relative growth rates of 0.02-0.04 d^-1, showing the not toxic effect of the antibiotic on the macrophyte growth. On the other hand, the BMG kinetic model best describes the removal of MNZ by phytoremediation. Finally, applying the Fenton process as a pretreatment makes the MNZ more assimilable for the phytoremediation system, converting the integration of Fenton with the phytoremediation like other attractive technology to be considered in removing emerging compounds.

Joint toxicity mechanisms of perfluorooctanoic acid and sulfadiazine on submerged macrophytes and periphytic biofilms

Hazardous chemicals, such as perfluoroalkyl substances (PFASs) and antibiotics, coexist in aquatic environments and pose a severe threat to aquatic organisms. However, research into the toxicity of these pollutants on submerged macrophytes and their periphyton is still limited. To assess their combined toxicity, Vallisneria natans (V. natans) was exposed to perfluorooctanoic acid (PFOA) and sulfadiazine (SD) at environmental concentrations. Photosynthetic parameters such as chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids were lower in the SD exposure group, indicating that SD had a significant effect on the photosynthesis of aquatic plants. Single and combined exposures effectively induced antioxidant responses, with increases in superoxide dismutase, peroxidase activities, and ribulose-1,5-bisphosphate carboxylase concentrations, as well as malondialdehyde content. Accordingly, antagonistic toxicity was assessed between PFOA and SD. Furthermore, metabolomics revealed that V. natans improved stress tolerance through changes in enoic acid, palmitic acid, and palmitoleoyloxymyristic acid related to the fatty acid metabolism pathway responding to the coexisting pollutants. Additionally, PFOA and SD in combination induced more effects on the microbial community of biofilm. The alternation of α- and β-D-glucopyranose polysaccharides and the increased content of autoinducer peptides and N-acylated homoserine lactones indicated that PFOA and SD changed the structure and function of biofilm. These investigations provide a broader perspective and comprehensive analysis of the responses of aquatic plants and periphyton biofilms to PFAS and antibiotics in the environment.

Investigating the Transformation Products of Selected Antibiotics and 17 α-Ethinylestradiol under Three In Vitro Biotransformation Models for Anticipating Their Relevance in Bioaugmented Constructed Wetlands

The degradation of three antibiotics (sulfamethoxazole, trimethoprim, and ofloxacin) and one synthetic hormone (17 α-ethinylestradiol) was investigated in three in-vitro biotransformation models (i.e., pure enzymes, hairy root, and Trichoderma asperellum cultures) for anticipating the relevance of the formation of transformation products (TPs) in constructed wetlands (CWs) bioaugmented with T. asperellum fungus. The identification of TPs was carried out employing high-resolution mass spectrometry, using databases, or by interpreting MS/MS spectra. An enzymatic reaction with β-glucosidase was also used to confirm the presence of glycosyl-conjugates. The results showed synergies in the transformation mechanisms between these three models. Phase II conjugation reactions and overall glycosylation reactions predominated in hairy root cultures, while phase I metabolization reactions (e.g., hydroxylation and N-dealkylation) predominated in T. asperellum cultures. Following their accumulation/degradation kinetic profiles helped in determining the most relevant TPs. Identified TPs contributed to the overall residual antimicrobial activity because phase I metabolites can be more reactive and glucose-conjugated TPs can be transformed back into parent compounds. Similar to other biological treatments, the formation of TPs in CWs is of concern and deserves to be investigated with simple in vitro models to avoid the complexity of field-scale studies. This paper brings new findings on the emerging pollutants metabolic pathways established between T. asperellum and model plants, including extracellular enzymes.

Assessing phytotoxicity of microplastics on aquatic plants using fluorescent microplastics

Although studies on microplastics are increasing every year, still very little is known about their toxicity. Especially for plant species, even studies of uptake of microplastics are only few, not to mention phytotoxicity of microplastics. Therefore, we conducted a pilot study on the phytotoxicity of 1-μm-sized fluorescent microplastics (FMPs) on the free-floating aquatic plants Spirodela polyrhiza and Salvinia natans and the emergent aquatic plant Phragmites australis using 0.1% and 0.01% FMP treatment. Furthermore, uptake of FMPs by plants was verified by detecting fluorescence of FMPs by laser. A free-floating aquatic plant S. polyrhiza and emergent aquatic plant P. australis showed significantly decreased harvested biomass after 3 weeks indicating phytotoxicity of FMPs, but S. natans did not show any differences of harvested biomass or chlorophyll contents among treatments. Detection of fluorescence from plant leaves provided evidence of active FMPs uptake by plants. The emission spectra of plant leaves in 0.1% FMP treatment showed similar peaks to those of free fluorescent microplastics, providing a firm evidence of FMPs uptake by plants. This study is one of the pioneering studies to explore fluorescent microplastic uptake and toxicity in aquatic plants and therefore provides a baseline for further studies.

Study effect and mechanism of ofloxacin and levofloxacin on development of Rana nigromaculata tadpoles based on the hypothalamus-pituitary-thyroid axis

Excessive antibiotics transferred into the aquatic environment may affect the development of amphibians. Previous studies on the aquatic ecological risk of ofloxacin generally ignored its enantiomers. The purpose of this study was to compare the effects and mechanisms of ofloxacin (OFL) and levofloxacin (LEV) on the early development of Rana nigromaculata. After 28-day exposure at environmental levels, we found that LEV exerted more severe inhibitory effects on the development of tadpoles than OFL. According to the enrichment results of differentially expressed genes in the LEV and OFL treatments, LEV and OFL had different effects on the thyroid development of tadpoles. dio2 and trh were affected by the regulation of dexofloxacin instead of LEV. At the protein level, LEV was the main component that affected thyroid development-related protein, while dexofloxacin in OFL had little effect on thyroid development. Furthermore, molecular docking results further confirmed that LEV was a major component affecting thyroid development-related proteins, including DIO and TSH. In summary, OFL and LEV regulated the thyroid axis by differential binding to DIO and TSH proteins, thereby exerting differential effects on the thyroid development of tadpoles. Our research is of great significance for comprehensive assessment of chiral antibiotics aquatic ecological risk.

Response of submerged macrophytes and biofilms to coexisting azithromycin and tetracycline: Antibiotic resistance genes removal, toxicity assessment and microbial properties

Antibiotics, such as azithromycin (AZ), tetracycline (TC), and their related antibiotic resistance genes (ARGs), create serious ecological risks to aquatic organisms. This study examined the response mechanisms of submerged macrophytes and periphytic biofilms to a mixture of AZ and TC pollution and determined the antibiotic removal efficiencies and fate of ARGs. The results showed that the plant-biofilm system had a significant capacity for removing both single and combined antibiotics with removal efficiencies of 93.06% ∼99.80% for AZ and 73.35% ∼97.74% for TC. Higher ARG (tetA, tetC, tetW, ermF, ermX, and ermB) abundances were observed in the biofilm, and subsequent exposure to the antibiotic mixture increased the abundances of these genes. Both single and combined antibiotics triggered antioxidant stress, but antagonistic effects were induced only with mixed AZ and TC exposure. Furthermore, the antibiotics changed the structural characteristics of extracellular polysaccharides and induced alterations in the structure of the biofilm microbial community. Increased N-acylated-l-homoserine lactone confirmed alternations in microbial quorum-sensing. The results extend the understanding of the fate of antibiotics and ARGs when aquatic plants and biofilms are exposed to antibiotic mixtures, as well as the organism's response mechanisms.

Duckweeds for Phytoremediation of Polluted Water

Tiny aquatic plants from the Lemnaceae family, commonly known as duckweeds, are often regarded as detrimental to the environment because of their ability to quickly populate and cover the surfaces of bodies of water. Due to their rapid vegetative propagation, duckweeds have one of the fastest growth rates among flowering plants and can accumulate large amounts of biomass in relatively short time periods. Due to the high yield of valuable biomass and ease of harvest, duckweeds can be used as feedstock for biofuels, animal feed, and other applications. Thanks to their efficient absorption of nitrogen- and phosphate-containing pollutants, duckweeds play an important role in the restorative ecology of water reservoirs. Moreover, compared to other species, duckweed species and ecotypes demonstrate exceptionally high adaptivity to a variety of environmental factors; indeed, duckweeds remove and convert many contaminants, such as nitrogen, into plant biomass. The global distribution of duckweeds and their tolerance of ammonia, heavy metals, other pollutants, and stresses are the major factors highlighting their potential for use in purifying agricultural, municipal, and some industrial wastewater. In summary, duckweeds are a powerful tool for bioremediation that can reduce anthropogenic pollution in aquatic ecosystems and prevent water eutrophication in a simple, inexpensive ecologically friendly way. Here we review the potential for using duckweeds in phytoremediation of several major water pollutants: mineral nitrogen and phosphorus, various organic chemicals, and heavy metals.

Removal of pharmaceutical active compounds in wastewater by constructed wetlands: Performance and mechanisms

The occurrence of pharmaceutical active compounds (PhACs) in aquatic environments is a cause for concern due to potential adverse effects on human and ecosystem health. Constructed wetlands (CWs) are cost-efficient and sustainable wastewater treatment systems for the removal of these PhACs. The removal processes and mechanisms comprise a complex interplay of photodegradation, biodegradation, phytoremediation, and sorption. This review synthesized the current knowledge on CWs for the removal of 20 widely detected PhACs in wastewater. In addition, the major removal mechanisms and influencing factors are discussed, enabling comprehensive and critical understanding for optimizing the removal of PhACs in CWs. Consequently, potential strategies for intensifying CWs system performance for PhACs removal are discussed. Overall, the results of this review showed that CWs performance in the elimination of some pharmaceuticals was on a par with conventional wastewater treatment plants (WWTPs) and, for others, it was above par. Furthermore, the findings indicated that system design, operational, and environmental factors played important but highly variable roles in the removal of pharmaceuticals. Nonetheless, although CWs were proven to be a more cost-efficient and sustainable technology for pharmaceuticals removal than other engineered treatment systems, there were still several research gaps to be addressed, mainly including the fate of a broad range of emerging contaminants in CWs, identification of specific functional microorganisms, transformation pathways of specific pharmaceuticals, assessment of transformation products and the ecotoxicity evaluation of CWs effluents.

Physiological responses and antibiotic-degradation capacity of duckweed (Lemna aequinoctialis) exposed to streptomycin

Aquatic plants are constantly exposed to various water environmental pollutants. Few data on how antibiotics affect duckweed health and its removal ability. The aim of this study was to investigate the impact of streptomycin on the physiological change and uptake capability in duckweed (Lemna aequinoctialis) after exposure at different time points (0, 5, 10, 15 and 20 days). Duckweeds were exposed to streptomycin at a range of concentrations (0.1-10 mM). Results indicated that the high streptomycin concentrations (≥1 mM) resulted in a lower duckweed biomass (21.5-41.5%), RGR (0.258-0.336 g d^-1), decrease in total Chl and increase in carotenoids. Antioxidative enzymes, including CAT (18-42.88 U mg protein^-1), APX (0.41-0.76 U mg protein^-1), and SOD (0.52-0.71 U mg protein^-1) were found to accumulate in the streptomycin groups in comparison to the control group. The significant reduction (72-82%) in streptomycin content at 20 d compared to the control (40-55%) suggested that duckweed has a high ability in removing streptomycin. Transcriptome analysis showed that the secondary metabolic pathways including phenylpropanoid biosynthesis and flavonoid biosynthesis were significantly upregulated in the streptomycin setup compared to the control. Therefore, our findings suggested that duckweed can contribute to the streptomycin degradation, which should be highly recommended to the treatment of aquaculture wastewater and domestic sewage.

Natural detoxification of antibiotics in the environment: A one health perspective

The extended concept of one health integrates biological, geological, and chemical (bio-geo-chemical) components. Anthropogenic antibiotics are constantly and increasingly released into the soil and water environments. The fate of these drugs in the thin Earth space ("critical zone") where the biosphere is placed determines the effect of antimicrobial agents on the microbiosphere, which can potentially alter the composition of the ecosystem and lead to the selection of antibiotic-resistant microorganisms including animal and human pathogens. However, soil and water environments are highly heterogeneous in their local composition; thus the permanence and activity of antibiotics. This is a case of "molecular ecology": antibiotic molecules are adsorbed and eventually inactivated by interacting with biotic and abiotic molecules that are present at different concentrations in different places. There are poorly explored aspects of the pharmacodynamics (PD, biological action) and pharmacokinetics (PK, rates of decay) of antibiotics in water and soil environments. In this review, we explore the various biotic and abiotic factors contributing to antibiotic detoxification in the environment. These factors range from spontaneous degradation to the detoxifying effects produced by clay minerals (forming geochemical platforms with degradative reactions influenced by light, metals, or pH), charcoal, natural organic matter (including cellulose and chitin), biodegradation by bacterial populations and complex bacterial consortia (including "bacterial subsistence"; in other words, microbes taking antibiotics as nutrients), by planktonic microalgae, fungi, plant removal and degradation, or sequestration by living and dead cells (necrobiome detoxification). Many of these processes occur in particulated material where bacteria from various origins (microbiota coalescence) might also attach (microbiotic particles), thereby determining the antibiotic environmental PK/PD and influencing the local selection of antibiotic resistant bacteria. The exploration of this complex field requires a multidisciplinary effort in developing the molecular ecology of antibiotics, but could result in a much more precise determination of the one health hazards of antibiotic production and release.

Occurrence and distribution of antibiotics in coastal water of the Taizhou Bay, China: impacts of industrial activities and marine aquaculture

The occurrence, spatial distribution, and source analysis of antibiotics in global coastal waters and estuaries are not well documented or understood. Therefore, the distribution of 14 antibiotics in inflowing river and bay water of Taizhou Bay, East China Sea, was studied. Thirteen antibiotics, excluding roxithromycin (ROM), were all detected in inflowing river and bay water. The total antibiotic concentrations in bay water ranged from 3126.62 to 26,531.48 ng/L, which were significantly higher than those in the inflowing river (17.20-25,090.25 ng/L). Macrolides (MAs) and sulfonamides (SAs) were dominant in inflowing river (accounting for 24.40% and 74.9% of the total antibiotic concentrations, respectively), while SAs in bay water (93.6% of the total concentrations). Among them, clindamycin (CLI) (concentration range: ND-8414 ng/L, mean 1437.59 ng/L) and sulfadimidine (SMX) (ND-25,184.00 ng/L, mean concentrations: 9107.88 ng/L) were the highest in those surface water samples. Source analysis showed that MAs and SAs in the inflowing river mainly came from the wastewater discharge of the surrounding residents and pharmaceutical companies, while SAs in the bay water mainly came from surrounding industrial activities and mariculture. However, the contribution of the inflowing river to the bay water cannot be ignored. The risk assessment showed that SMX and ofloxacin (OFX) have potential ecological risks. These data will support the various sectors of the environment in developing management strategies and to prevent antibiotic pollution.

Long-term chemically protected sodium butyrate supplementation in broilers as an antibiotic alternative to dynamically modulate gut microbiota

Chemically protected sodium butyrate (CSB) is a new kind of sodium butyrate. Our previous study found that 1,000 mg/kg of CSB had the potential capacity of improving growth performance and promoting early development of small intestine in broilers. This study aimed to investigate the effect of long-term antibiotics or CSB supplementation for intestinal microflora dynamical regulation in broilers. One hundred ninety-two 1-day-old Arbor Acres male broilers were randomly allocated into 3 dietary treatment (8 replicates per treatment) and fed with a basal diet (CON), a diet supplemented with the antibiotics (enramycin, 8 mg/kg and aureomycin, 100 mg/kg) (ANT), or a diet supplemented with 1,000 mg/kg of CSB, respectively. Results showed that dietary supplementation of CSB or ANT treatment elevated the weight gain and feed conversion ratio (FCR; P < 0.05), as compared with control (CON) group. Additionally, CON, CSB, or ANT administration dynamically altered the gut microbiota composition as time goes on. The increased presence of potential pathogens, such as Romboutsia and Shuttleworthia, and decreased beneficial bacteria such as Alistipes, Akkermansia, and Bacteroides were verified in new gut homeostasis reshaped by long-term antibiotics treatment, which has adverse effects on intestinal development and health of broilers. Conversely, CSB supplementation could dynamically enhance the relative abundance of Bacteroides, and decrease Romboutsia and Shuttleworthia in new microflora, which has positive effects on intestinal bacteria of broilers compared with CON group. Meanwhile, CSB supplementation was significantly increased the concentration of propionic acid and total short chain fatty acids (total SCFA; P < 0.05) in comparison with CON and ANT groups. Moreover, CSB treatment significantly increased anti-inflammatory and antioxidative capacities (P < 0.05) of broilers compared with ANT group. Taken together, we revealed characteristic structural changes of gut microbiota throughout long-term CSB or ANT supplementation in broilers, which provided a basic data for evaluating the mechanism of action affecting intestinal health by CSB or ANT administration and CSB as an alternative to antibiotics in the broilers industry.

Reproductive toxicities of ofloxacin and norfloxacin on Caenorhabditis elegans with multi-generational oscillatory effects and trans-generational residual influences

The reproductive toxicities over generations are essential to assess the long-term impacts environmental fluoroquinolone antibiotics (FQs). In the present study, the multi-generational effects of ofloxacin (OFL) and norfloxacin (NOR) on reproduction were studied on Caenorhabditis elegans from 9 successive generations (F1-F9). Results showed that OFL showed no effects in F1, stimulation in F2 to F4, and inhibition F5 to F9. The effects of NOR also showed oscillation between stimulation and inhibition across generations. Further biochemical analysis demonstrated that the reproductive toxicities of OFL and NOR were more closely connected with total cholesterol (TCHO), progesterone (P) and testosterone (T), than major sperm protein (MSP) and vitellogenin (Vn). Moreover, OFL and NOR also showed significant trans-generational reproductive toxicities in T4 and T4', the great-grand-daughter of F1 and F9. Differences between T4 and T4' and between OFL and NOR, indicated influences of multi-generational exposure and urged more exploration on different mechanisms between FQs.

Application of duckweed (Lemna sp.) and water fern (Azolla sp.) in the removal of pharmaceutical residues in water: State of art focus on antibiotics

In recent decades, antibiotic residues in the environment have increased, affecting components of biological communities, from bacteria to plants and animals. Different methods have been used to remove these compounds, including phytoremediation with floating aquatic species such as duckweed and aquatic fern, with positive results. This study analyses information about the removal efficiency of drugs, with a focus on antibiotics, using Lemna and Azolla, which will allow a better understanding of phytoremediation processes from the perspective of plant physiology. The physiological processes of macrophytes in an environment with this type of pollutant and the phytotoxic effects on plants at high concentrations are also analysed. The metabolization of toxic compounds occurs in three phases: phase I begins with the absorption of antibiotics and the secretion of reactive oxygen species (ROS); in phase II, the effects of ROS are neutralized and minimized by conjugation with enzymes such as glutathione transferase or metabolites such as glutathione; and phase III culminates with the storage of the assimilated compounds in the vacuoles, apoplast and cell wall. In this way, plants contribute to the removal of toxic compounds. In summary, there is sufficient scientific evidence on the efficiency of the elimination of pharmaceutical compounds by these floating macrophytes at the laboratory scale, which indicates that their application under real conditions can have good results.

Phytotoxicity of environmental norfloxacin concentrations on the aquatic plant Spirodela polyrrhiza: Evaluation of growth parameters, photosynthetic toxicity and biochemical traits

As an emerging pollutant, the increasing use of antibiotics in wastewater posed a serious threat to non-target organisms in the environment. Duckweed (Spirodela polyrrhiza) is a common higher aquatic plant broadly used in phytotoxicity tests for xenobiotic substances. The aim of this study was to evaluate the chronic toxicity of norfloxacin (NOR) on Spirodela polyrrhiza during 18 days of exposure. Our study investigated the addition of NOR into the medium with environment-related concentrations (0, 0.1, 10, and 1000 μg L^-1). Subsequently, biomarkers of toxicity such as growth, pigment, chlorophyll fluorescence parameters, indicators of oxidative stress, and osmotic regulatory substances content were analyzed in duckweed. In response to NOR exposure, obvious chlorosis, declines in growth and photosynthetic pigment, and photosystem II inhibition were noted in a concentration dependent manner. Reactive oxygen species (ROS) and antioxidant activity content increased in the treated fronds, which indicated that oxidative stress was specifically affected by NOR exposure. A slight increase in osmotic regulatory substances in NOR treated setups than in the control represented the increasing stress resistance. These results suggest NOR exerts its toxic effects on the aquatic plant Spirodela polyrrhiza.

Removal of Dinotefuran, Thiacloprid, and Imidaclothiz Neonicotinoids in Water Using a Novel Pseudomonas monteilii FC02-Duckweed (Lemna aequinoctialis) Partnership

Neonicotinoids (NEOs) are the most widely used insecticides in the world and pose a serious threat to aquatic ecosystems. The combined use of free-floating aquatic plants and associated microorganisms has a tremendous potential for remediating water contaminated by pesticides. The aim of this study was to determine whether plant growth-promoting bacteria (PGPB) could enhance the phytoremediation efficiency of duckweed (Lemna aequinoctialis) in NEO-contaminated water. A total of 18 different bacteria were isolated from pesticide-stressed agricultural soil. One of the isolates, Pseudomonas monteilii FC02, exhibited an excellent ability to promote duckweed growth and was selected for the NEO removal experiment. The influence of strain FC02 inoculation on the accumulation of three typical NEOs (dinotefuran, thiacloprid, and imidaclothiz) in plant tissues, the removal efficiency in water, and plant growth parameters were evaluated during the 14-day experimental period. The results showed that strain FC02 inoculation significantly (p < 0.05) increased plant biomass production and NEO accumulation in plant tissues. The maximum NEO removal efficiencies were observed in the inoculated duckweed treatment after 14 days, with 92.23, 87.75, and 96.42% for dinotefuran, thiacloprid, and imidaclothiz, respectively. This study offers a novel view on the bioremediation of NEOs in aquatic environments by a PGPB–duckweed partnership.

Phytoremediation by ornamental plants: a beautiful and ecological alternative

Phytoremediation is an eco-friendly and economical technology in which plants are used for the removal of contaminants presents in the urban and rural environment. One of the challenges of the technique is the proper destination of the biomass of plants. In this context, the use of ornamental plants in areas under contamination treatment improves landscape, serving as a tourist option and source of income with high added value. In addition to their high stress tolerance, rapid growth, high biomass production, and good root development, ornamental species are not intended for animal and human food consumption, avoiding the introduction of contaminants into the food web in addition to improving the environments with aesthetic value. Furthermore, ornamental plants provide multiple ecosystem services, and promote human well-being, while contributing to the conservation of biodiversity. In this review, we summarized the main uses of ornamental plants in phytoremediation of contaminated soil, air, and water. We discuss the potential use of ornamental plants in constructed buffer strips aiming to mitigate the contamination of agricultural lands occurring in the vicinity of sources of contaminants. Moreover, we underlie the ecological and health benefits of the use of ornamental plants in urban and rural landscape projects. This study is expected to draw attention to a promising decontamination technology combined with the beautification of urban and rural areas as well as a possible alternative source of income and diversification in horticultural production.

The fate of sulfonamides in the process of phytoremediation in hydroponics

Phytoremediation has been proven to be an alternative in-situ treatment technique for sulfonamide polluted wastewater. However, the fate of sulfonamides in the phytoremediation process of multiple sulfonamides coexistence is unclear. Therefore, the possibility and mechanism of phytoremediation of ten sulfonamides by different wetland plants through hydroponics were investigated in this study. The phytoremediation rates of Σsulfonamides by different wetland plants were from 44.5% to 56.9%. Mass balance analysis showed that rhizosphere biodegradation (90.2% - 92.2%) dominated the phytoremediation of Σsulfonamides, while hydrolysis (7.63% - 8.95%) and plant uptake (0.05% - 0.17%) accounted for a small proportion. It is worth mentioning that the dissipation of the target sulfonamides in the hydroponic system followed the first-order reaction kinetic model, with half-lives of 13.3 d to 53.3 d, which are close to or even lower than that of aerobic biodegradation in river water, sediment, and piggery wastewater. Six of the ten spiked sulfonamides were detected in plant samples demonstrated that the selective uptake of plants under the coexistence of multiple sulfonamides. The distribution of sulfonamides (concentrations and uptake amounts) in plant tissues followed the sequence of root > stem > leaf in this study, but the distribution in stems and leaves needs further study. The uptake and rhizosphere biodegradation of Cyperus papyrus to sulfonamides are optimally resulting that its phytoremediation rate is significantly higher than other plants (p < 0.05), which indicates that plant species is one of the key factors affecting the phytoremediation efficiency of sulfonamides. These findings verify the feasibility of phytoremediation of sulfonamides, and provide new insights into the fate of sulfonamides in the process of phytoremediation.

Acetaminophen Induces an Antioxidative Response in Lettuce Plants

Contaminants of environmental concern, like pharmaceuticals, are being detected in increasing amounts in soils and irrigation waters and can thus be taken up by plants. In this work, the uptake of acetaminophen (ACT) by lettuce plants was evaluated through a hydroponic experiment at different concentrations (0, 0.1, 1 and 5 mg L⁻¹ ACT). The pathways related to oxidative stress induced by ACT were studied in lettuce leaves and roots at 1, 8 and 15 days after exposure. Stress indicators such as hydrogen peroxide and malondialdehyde (MDA) contents were analyzed, revealing increases in plants contaminated with ACT in comparison to control, confirming the occurrence of oxidative stress, with the exception of MDA in leaves. The enzymatic activities of catalase, superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase and glutathione peroxidase, directly involved in the antioxidative system, showed significant differences when compared to control plants, and, depending on the enzyme and the tissue, different trends were observed. Glutathione reductase revealed a decrease in contaminated leaves, which may imply a specific impact of ACT in the glutathione cycle. Significant increases were found in the anthocyanin content of leaves, both with exposure time and ACT concentration, indicating an antioxidative response induced by ACT contamination.

Irrigation with secondary municipal-treated wastewater: Potential effects, accumulation of typical antibiotics and grain quality responses in rice (Oryza sativa L.)

Using secondary treated wastewater to irrigate paddies presents an exposure pathway for antibiotics to enter the terrestrial food chain. To date, there has been no information on the biochemical reactions and antibiotic uptake in rice plants irrigated with secondary treated wastewater. The present study investigated antibiotic uptake and concentration-response trends in rice tissues and evaluated the effects of typical antibiotics (tetracycline, roxithromycin, ofloxacin, and sulfamethoxazole) on rice growth, grain yield and quality, and rice physiobiochemical characters via irrigation using treated wastewater augmented with varying concentrations (0-500 µg/L) in paddies. The results showed that the antibiotic accumulation in rice plants irrigated with treated wastewater was limited, and the studied antibiotics were not detected in rice grains (edible parts). The ability of rice to withstand certain antibiotics and grow in a healthy manner is attributed to the capacity to maintain reasonably normal photosynthesis activity and to elevate antioxidative defenses. The highest antibiotic concentration (500 µg/L) did not reduce the processing quality of the rice grain, but it enhanced the cooking and eating quality. From the obtained results, it can be concluded that secondary treated wastewater for paddy irrigation is an alternative water resource securing protection from the environment and rice grain quality.

Advances and Applications of Water Phytoremediation: A Potential Biotechnological Approach for the Treatment of Heavy Metals from Contaminated Water

Potable and good-quality drinking water availability is a serious global concern, since several pollution sources significantly contribute to low water quality. Amongst these pollution sources, several are releasing an array of hazardous agents into various environmental and water matrices. Unfortunately, there are not very many ecologically friendly systems available to treat the contaminated environment exclusively. Consequently, heavy metal water contamination leads to many diseases in humans, such as cardiopulmonary diseases and cytotoxicity, among others. To solve this problem, there are a plethora of emerging technologies that play an important role in defining treatment strategies. Phytoremediation, the usage of plants to remove contaminants, is a technology that has been widely used to remediate pollution in soils, with particular reference to toxic elements. Thus, hydroponic systems coupled with bioremediation for the removal of water contaminants have shown great relevance. In this review, we addressed several studies that support the development of phytoremediation systems in water. We cover the importance of applied science and environmental engineering to generate sustainable strategies to improve water quality. In this context, the phytoremediation capabilities of different plant species and possible obstacles that phytoremediation systems may encounter are discussed with suitable examples by comparing different mechanistic processes. According to the presented data, there are a wide range of plant species with water phytoremediation potential that need to be studied from a multidisciplinary perspective to make water phytoremediation a viable method.

The Potential of Chaetoceros muelleri in Bioremediation of Antibiotics: Performance and Optimization

Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, most consumed antibiotics are excreted into wastewater as metabolites or in their original form. Therefore, removal of antibiotics from aquatic environments is of high research interest. In this study, we investigated the removal of sulfamethoxazole (SMX) and ofloxacin (OFX) with Chaetoceros muelleri, a marine diatom. The optimization process was conducted using response surface methodology (RSM) with two independent parameters, i.e., the initial concentration of antibiotics and contact time. The optimum removal of SMX and OFX were 39.8% (0.19 mg L⁻¹) and 42.5% (0.21 mg L⁻¹) at the initial concentration (0.5 mg L⁻¹) and contact time (6.3 days). Apart from that, the toxicity effect of antibiotics on the diatom was monitored in different SMX and OFX concentrations (0 to 50 mg L⁻¹). The protein (mg L⁻¹) and carotenoid (μg L⁻¹) content increased when the antibiotic concentration increased up to 20 mg L⁻¹, while cell viability was not significantly affected up to 20 mg L⁻¹ of antibiotic concentration. Protein content, carotenoid, and cell viability decreased during high antibiotic concentrations (more than 20 to 30 mg L⁻¹). This study revealed that the use of Chaetoceros muelleri is an appealing solution to remove certain antibiotics from wastewater.

Occurrence of typical antibiotics, representative antibiotic-resistant bacteria, and genes in fresh and stored source-separated human urine

Human urine is a source of fertilizer and, with proper management, it can be reused in agriculture. Determining the contamination issue of antibiotics in source-separated urine is important because the majority of antibiotics are excreted with urine. In this study, source-separated urine samples were randomly collected from a male toilet in a university building and analyzed in terms of 30 typical antibiotics (including 14 sulfonamides, 4 tetracyclines, and 12 fluoroquinolones) and tetracycline-resistant Escherichia coli, as well as its antibiotic-resistant genes to determine the contamination characteristics of antibiotic-related pollution in fresh and stored urine. Results showed that 18 out of 30 typical antibiotics were detected in fresh source-separated human urine. The dominant antibiotic was oxytetracycline with a frequency of 100%, followed by tetracycline, sparfloxacin, enrofloxacin, and ofloxacin, which demonstrated a detection frequency of 55%. Among the detected values, sulfonamides (2 antibiotics), tetracyclines (4 antibiotics), and fluoroquinolones (12 antibiotics) had a concentration range of 0.25-2.94, 0.94-41.2, and 0.06-163.16 ng/mL, respectively. Furthermore, tetracycline-resistant Escherichia coli, which was measured using plate count method, and its related gene, tet M, exhibited a maximum cell density of (200,000 ± 5000) CFU/100 mL and (2.73 ± 0.261) × 10⁷ copies/mL, respectively. When the fresh urine was stored in an ambient environment for 30 days to simulate the real circumstances of urine management, a significant reduction in antibiotics and antibiotic-resistant bacteria was observed, while the change in antibiotic-resistant genes was insignificant. The results of this study suggest that risks associated with antibiotics and their antibiotic-resistant bacteria and genes are retained during collection and storage. Hence, these kinds of microcontaminants must be considered in further urine utilization.

Microalgal and duckweed based constructed wetlands for swine wastewater treatment: A review

Constructed wetlands for swine wastewater treatment have been one of the most exciting research topics. Usually hydrophytes based constructed wetlands could not adapt well to high concentration of ammonia nitrogen in swine wastewater, while microalgal and duckweed based constructed wetlands are promising for the nutrient removal. In this critical review, the important roles of microalgae and duckweeds played in wastewater treatment in constructed wetlands were first summarized. Performances including biomass growth, nutrient removal capacities and mechanisms of microalgal and duckweed based constructed wetlands were reviewed for swine wastewater treatment. Challenges for the applications of constructed wetlands including microalgal and duckweed based ones were discussed which includes a better understanding and utilization of synergistic effects among microalgae and duckweeds, difficulty and costs in harvesting biomass, applications in various field conditions including low temperatures, and selections of various types of microalgal and duckweed species. Future research needs were also proposed accordingly.

Ti-pillared montmorillonite clay for adsorptive removal of amoxicillin, imipramine, diclofenac-sodium, and paracetamol from water

The adsorptive removal of natural montmorillonite (MMT) clay pillared with titanium oxide (Ti-PILC) was examined in this study to see the adsorptive remove of pharmaceutical compounds (PCs): amoxicillin (AMOX), imipramine (IMP), Diclofenac-Sodium (DIF-S), and paracetamol (PCM) from water under a batch-scale study. The post-intercalation changes in clay were investigated with various surface and structural analysis techniques. The results confirm an increase in the surface area, microporosity, and acidic sites (lewis acid) which improved and regulates Ti-PILC interactions with electron-rich PPCPs molecules. The FTIR bands for Si-OH and Al-OH show a shift in MMT, after pillaring, indicates the intercalation of Ti pillared in its interlayer space. The isotherms studies suggested the best fitting of Redlich Peterson models for all pharmaceutical adsorption data. The Langmuir adsorption (maximum) was recorded for Ti-PILC in the order: 82.68 (IMP) > 23.05 (DIF-S) > 20.83 (PCM) > 4.26 (AMOX) mg.g^-1 at a fixed adsorbent dose i.e. 0.1 g·L^-1. The PCs adsorption kinetics was also evaluated by Pseudo-first-, and second-order model and results showed the best curve fitting for all PCs. Results of regeneration studies showed that modified Ti-PILC could be a low-cost cleaner material for adsorption of pharmaceuticals from water.

The Uptake of Ivermectin and Its Effects in Roots, Leaves and Seeds of Soybean (Glycine max)

In recent years interest has grown in the occurrence and the effects of pharmaceuticals in the environment. The aim of this work is to evaluate the risk of fertilizing crops with manure from livestock treated with anthelmintics. The present study was designed to follow the fate of the commonly used anthelmintic drug, ivermectin (IVM) and its metabolites in soybeans (Glycine max (L.) Merr.), a plant that is grown and consumed world-wide for its high content of nutritional and health-beneficial substances. In vitro plantlets and soybean plants, cultivated in a greenhouse, were used for this purpose. Our results showed the uptake of IVM and its translocation to the leaves, but not in the pods and the beans. Four IVM metabolites were detected in the roots, and one in the leaves. IVM exposure decreased slightly the number and weight of the beans and induced changes in the activities of antioxidant enzymes. In addition, the presence of IVM affected the proportion of individual isoflavones and reduced the content of isoflavones aglycones, which might decrease the therapeutic value of soybeans. Fertilization of soybean fields with manure from IVM-treated animals appears to be safe for humans, due to the absence of IVM in beans, the food part of plants. On the other hand, it could negatively affect soybean plants and herbivorous invertebrates.

Accumulation characteristics and biological response of ginger to sulfamethoxazole and ofloxacin

The potential risk to human health of antibiotics that pass through the food chain has become an important global issue, but there are few reports on the response of ginger (Zingiber officinale) to antibiotic pollution. In this study, we investigated the enrichment characteristics and biological response of ginger to sulfamethoxazole (SMZ) and ofloxacin (OFL) residues, which are common in the environment. Lower levels of SMZ, OFL and their combined duplex treatment (SMZ+OFL) promoted the growth of ginger, but the critical doses necessary to stimulate growth differed among treatments: 10 mg L-1 SMZ, 1 mg L-1 OFL and 1 mg L-1 (SMZ+OFL) had the strongest stimulating effects. At higher dosages, the root growth and light energy utilization efficiency of ginger were impaired, and (SMZ+OFL) had the strongest inhibitory effect. Treatments with lower levels of antibiotics had no significant effect on reactive oxygen species and antioxidant enzyme activities. However, when SMZ, OFL and SMZ+OFL concentrations exceeded 10 mg L-1, the contents of H2O2, O2- and MDA continued to increase, while the activities of SOD, POD, CAT first increased and then decreased, especially in SMZ+OFL. Ginger accumulated more SMZ and OFL in rhizomes and less in leaves, and accumulation increased significantly as antibiotic concentration increased. When SMZ concentration was 1 mg L-1, the SMZ concentrations in rhizomes, roots, and leaves were 0.23, 0.15, and 0.05 mg kg-1, respectively, and the residual SMZ in the rhizome was 2.3 times higher than the maximum residue limit. The abundance of the resistance genes sul1, sul2, qnrS, and intI1 increased with increasing antibiotic concentrations, and intI1 abundance was the highest. OFL induced higher levels of intI1 expression than did SMZ.

Phytoremediation—From Environment Cleaning to Energy Generation—Current Status and Future Perspectives

Phytoremediation is a technology based on the use of green plants to remove, relocate, deactivate, or destroy harmful environmental pollutants such as heavy metals, radionuclides, hydrocarbons, and pharmaceuticals. Under the general term of phytoremediation, several processes with distinctively different mechanisms of action are hidden. In this paper, the most popular modes of phytoremediation are described and discussed. A broad but concise review of available literature research with respect to the dominant process mechanism is provided. Moreover, methods of plant biomass utilization after harvesting, with particular regard to possibilities of “bio-ore” processing for metal recovery, or using energy crops as a valuable source for bio-energy production (bio-gas, bio-ethanol, bio-oil) are analyzed. Additionally, obstacles hindering the commercialization of phytoremediation are presented and discussed together with an indication of future research trends.

Elucidating biotransformation pathways of ofloxacin in lettuce (Lactuca sativa L)

Antibiotics can be uptaken by plants from soil desorption or directly from irrigation water, but their metabolization pathways in plants are largely unknown. In this paper, an analytical workflow based on high-resolution mass spectrometry was applied for the systematic identification of biotransformation products of ofloxacin in lettuce. The targeted metabolites were selected by comparing the mass chromatograms of exposed with control samples using an advanced spectra-processing method (Fragment Ion Search). The innovative methodology presented allowed us to identify a total of 11 metabolites, including 5 ofloxacin metabolites that are being reported for the first time in plants. Accordingly, major transformation pathways were proposed revealing insight into how ofloxacin and related chemicals are metabolized in lettuce. Furthermore, the influence of biotransformation on potential residual antimicrobial activity of identified compounds was discussed. Human exposure to antibiotics at doses below the minimum inhibitory concentrations is crucial in human risk assessment, including food ingestion; however, in the case of ofloxacin presented results reveal that plant metabolites should also be considered so as not to underestimate their risk.

Benzothiadiazole functionalized Co-doped MIL-53-NH2 with electron deficient units for enhanced photocatalytic degradation of bisphenol A and ofloxacin under visible light

Nowadays, designing highly active photocatalysts for pollutant degradation under visible light still remains a challenging problem. Herein, a novel benzothiadiazole functionalized Co-doped MOF-based photocatalyst with electron deficient unit was first synthesized via a feasible step-by-step assembly strategy. Benzothiadiazole, as typical electron deficient group, could effectively promote the separation and transfer of photoinduced charge carriers. The implantation of Co ion could be served as an effective mediator to further facilitate the charge transfer through a Co³⁺/Co²⁺ redox pathway. Interestingly, the as-synthesized Co-MIL-53-NH-BT exhibited significantly enhanced photocatalytic degradation capacity for BPA and OFX under visible light irradiation, with removal efficiency as high as 99.9 % and 99.8 % within 120 min. TOC analysis suggested that majority of contaminants had been degraded into CO₂ and H₂O. The important parameters influencing the photocatalytic activity were investigated, and the kinetics study was also conducted. The possible degradation pathways and the possible photocatalytic mechanism were proposed. More importantly, the as-synthesized Co-MIL-53-NH-BT showed good reusability, stability as well as universal applicability. To sum up, current work not only developed an efficient and visible-light active photocatalyst for treating organic-contaminated wastewater, but also afforded some novel insight into the utilization of benzothiadiazole in MOF-based photocatalyst towards improving photocatalytic activity.