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Iron (hydr)oxides as a kind of natural mineral actively participate in the transformation of organic pollutants, but there is a large knowledge gap in their impacts on photochemical processes of microplastics (MPs). This study is the first to examine the degradation of two ordinary plastic materials, polyethylene (PE) and polypropylene (PP), mediated by iron (hydr)oxides (goethite and hematite) under simulated solar light irradiation. Both iron (hydr)oxides significantly promoted the degradation of MPs (particularly PP) with a greater effect by goethite than hematite, related to hydroxyl radical (

Microplastics (MPs) have attracted a significant concern due to persistence and their adverse effects on organisms. In this review, we summarize the recent literature regarding the natural and artificial aging process of MPs, also discuss the associated aging characteristics and mechanisms of MPs. The aged MPs showed different morphological and chemical properties from the pristine MPs. Furthermore, to evaluate associated aging effects, the corresponding release of aging process of MPs were systematically revealed, including the additives and intermediates. Different types of organic pollutants and heavy metals additives are listed. In addition, the release of MPs is affected by environmental factors (i.e., Illumination, salinity, temperature and pH). Aged MPs are more easily absorbed by organisms and have different toxic effects from the pristine MPs. The potential risks of aging MPs and the release of MPs during aging are discussed in detail. Based on the current deficiency of published literatures, the prospects are proposed. Therefore, this review provides a direction for further study on the behaviors and the toxic effects of MPs in the environment.

The atmospheric microplastics (MPs) in indoor environment have attracted great attention in recent years. In the study, we selected five indoor study cases with students of different as the research objects, including kindergartens, primary schools, middle schools, high schools and university. The atmospheric MPs fallouts were continuously collected in the different study rooms. Simultaneously, the morphological characteristics and composition of MPs were also investigated. The level of MPs pollution greatly varied due to different characteristics of indoor environments. The highest and lowest abundance of MPs appeared in senior high school and kindergarten classroom, respectively. Fibers were the main form of MPs, since fibers were easily detached from the textile products. Besides, the abundance of MPs was significantly related to indoor population density and duration of human activity. This study provides the first evidence of atmospheric MPs in different study rooms, which could be helpful for understanding environmental behavior of MPs and providing further information to assess potential risks of exposure to indoor airborne MPs.

The widespread presence of microplastics (MPs) in the environment has led to the rise of the study on the interaction between MPs and microorganisms. The variety and characteristics of MPs in the environment make their interaction with microorganisms more complex. Recent studies have found that MPs can also serve as an important carrier for microorganisms to form fully developed biofilms on the substrates. The emergence of new ecological sites will also affect the ecosystem of water and soil. We present the latest knowledge of MPs' interactions with microorganisms and summarize their respective potential impacts on the environment. It was found that the main factors affecting microbial colonization on MPs were the characteristics of MPs, exposure time and environmental factors. Furthermore, microbial colonization on MPs can affect the composition and distribution of the microbial community in the environment, as well as the migration and transformation of other contaminants which also occur in the animal guts. When it come to the toxicity of MPs to microorganisms, it has been found that the main effects of MPs on microorganisms are the effect on microbial growth, photosynthesis of microorganisms and some single cells. In addition, the combined effects of MPs with heavy metals and organic compounds on microorganisms can be divided into antagonistic effects, synergistic toxicity, promoting effects and non-effects. In turn, microbes will have impacts on MPs in terms of degradation, absorption, transfer and deposition. In practical application, MPs will affect the biological treatment stage of sewage treatment. This review discusses the interaction mechanism and influencing factors between microorganisms and MPs. It also called for active exploration of methods for treating MPs with microorganisms in the actual environment, providing a theoretical basis for the treatment of microorganisms, and a better understanding of the environmental behavior and ecological risk assessment of MPs.

Microplastics (MPs) pollution is becoming a global environmental problem due to the ubiquity. Knowledge about transformation process of MPs under ultraviolet (UV) irradiation was critical to understanding the environmental fate of these particles. In this study, the photo-aging characteristics and mechanisms of polyvinyl chloride (PVC) under different UV irradiations in the air or water condition were comprehensively investigated. When the PVC was exposed to the UVA, UVB and UVC irradiation, the surface morphology, functional group, crystal structure, and elemental composition of PVC were systematically characterized. With the increasing of aging time, the PVC was identified as more oxygen-containing functional groups, higher carbonyl index, and higher crystallinity, especially under the UVC irradiation. Based on the Two-dimensional correlation Fourier transform infrared spectroscopy (2D-FTIR-COS), the active sites and aging sequence of functional groups were confirmed under UVA, UVB and UVC irradiation. The reactive oxygen species (ROS) were produced and increased with the aging time as the whole. Corresponding to the aging results, the intensity of ROS and toxicity from leaching under UVC irradiation was greater than that under UVA or UVB. These findings provide direct evidences of photo-aging processes of MPs and the potential ecological risks resulting from aging in the aquatic environments.

To clarify the function of the nitrogen-containing structures on the adsorption of heavy metals, nitrogen-enriched biochars (NBCs) mainly composed of pyrrolic, pyridinic, and graphitic nitrogen were prepared to investigate the interaction mechanism with Cd(II). The results of batch experiments revealed that the saturated Cd(II) adsorption capacities of Pr-NBC, Pd-NBC, and Gp-NBC were 12.68, 24.04, and 35.95 mg g−1 respectively. The strongest adsorption ability was found for the Gp-NBC and was ascribed to the enhancement of graphitic nitrogen. The results from SEM-EDS and XRD, and the zeta potentials for the materials revealed that carbonate precipitation, cation exchange, and electrostatic interactions contributed to the adsorption of Cd(II). XPS and FTIR demonstrated that nitrogen in the carbon framework might have promoted the adsorption by forming cation–π interactions between graphitic nitrogen and Cd(II). The electrostatic potential distribution of the nitrogen with different configurations fully confirmed this. The theoretical calculations also proved that graphitic nitrogen had the lowest interaction energy to Cd(II), which further verified the strong contribution of graphitic nitrogen to the adsorption of heavy metal. Nitrogen-enriched biochar effectively adsorbs, changes the migration process of heavy metals in the natural environment, and thus alleviates the current situation of heavy metal pollution.

Microplastics (MPs), known to cause environmental pollution, is attracting a growing attention worldwide owing to their extensive existence and potential risks to biota. The marginal sea areas are suspected to be especially susceptible to MPs pollution. Unfortunately, data on MPs in the surface water and sediments ecosystems are still limited, particularly in the southern coastal areas of China. The study was successfully utilized to explore the distribution and characteristics of MPs below 5 mm collected from 14 sites in the seas around Shenzhen, a typical special economic zone of China. MPs were detected in both surface water and sediments with concentrations ranging from 3.8 to 7.8 items per liter and 2.6 × 10

Tetracycline (TC) and Mn(II) is a common antibiotic and metal ion respectively. Nevertheless, literatures involving in the effects of Mn(II) on TC transformation are still insufficient. In this study, the kinetic experiment, spectral analysis, complexation experiment and electrochemical analysis, theoretical calculation and products detection were carried out to probe into oxidation and photolysis of TC with Mn(II). Mn(II) greatly accelerated TC oxidation, preferably tending to complex with TC at O10 - O12 or O2 - O3 site. There were a TC-Mn(II)/TC-Mn(III) redox couple and electron transfer process. Conversely, Mn(II) inhibited photolysis of TC. The photolysis of excited TC could compete with energy dissipation reactions. The electron transfer and complexation reaction easily made excited TC energy transfer, thus slowing down photolysis process. During the TC transformation, the intensity of functional groups was significantly decreased. Simultaneously, the degradation pathways mainly included eight reactions. It is a very interesting and probably overlooked phenomenon, which identifies new transformation of TC with Mn(II). This study helps to further understand fate and environmental behavior of antibiotics and metal ion.

It is well known that microplastics (MPs) may experience weathering and aging under ultraviolet light (UV) irradiation, but it remains unclear if these processes are impacted by natural components, such as clay minerals. In this study, we systematically investigated the photodegradation behaviors of polyvinyl chloride (PVC) and poly (ethylene terephthalate) (PET), two utmost used plastics, in the presence of clay minerals (kaolinite and montmorillonite). The results demonstrated that the clay minerals, particularly kaolinite, significantly promoted the MPs photodegradation, and the aging of PET was more prominent. The photodegradation was the most distinct at pH 7.0, regardless of the presence or absence of the clay minerals. The results of electron paramagnetic resonance and inhibition experiments of reactive oxygen species indicated that the minerals, particularly kaolinite, remarkably facilitated production of •OH, which was the key species contributing to the photodegradation of MPs. Specifically, UV irradiation facilitated the photo-ionization of MPs, producing hydrated electrons and MP radical cations (MP+). The Lewis base sites prevalent on the clay siloxane surfaces could stabilize the MP radical cations and prevent their recombination with hydrated electrons, which promoted the generation of •OH under aerobic conditions, and facilitated the degradation of MP. Two-dimensional (2D) Fourier transformation infrared (FTIR) correlation spectroscopy (COS) analysis and ultra-high-performance liquid chromatography coupled to a Q Exactive Orbitrap HF mass spectrometer were used to identify the sequential changes of functional groups, and the degradation products of the MPs. This study improves our understanding on the aging of MPs in the complex natural environment.

(Micro)plastics pollution has raised global concern because of its potential threat to the biota. The review on recent developments of photocatalytic degradation of (micro)plastics is still insufficient. In this study, we have discussed various bare and composites photocatalysts involved in the photocatalytic degradation of (micro)plastics. The photocatalytic mechanisms and factors affecting the degradation were also discussed. To improve the performance of photocatalysts, their surface is modified with metal or non-metal dopants. These doped photocatalysts are then compounded with a variety of environmentally friendly and nontoxic polymers to prepare multifunctional composites. The generation of reactive oxygen species (ROS) plays an important role in the photocatalytic degradation of (micro)plastics, and superoxide ions (O

The increasing presence of pesticides, pharmaceuticals and plasticizers in environmental media is threatening public health and ecosystems. Remediation of contaminated waters by Fenton-like photoreactions to degrade pollutants is considered as sustainable because this method mimics natural attenuation and involves safe iron oxides and oxalate. However, knowledge about the degradation efficiency of organic pollutants is scarce, notably in the presence of minerals. Here, we tested the degradation of the tetracycline antibiotic, the diethyl phthalate plasticizer, and the glyphosate herbicide using combinations of visible light, goethite (FeO(OH)), and oxalate. Pollutant residues were also extracted from the precipitate at the end of a reaction. Results show that pollutant removal, including adsorption and degradation, reached 99.7% for tetracycline, 87.1% for diethyl phthalate, and 83.3% for glyphosate using a goethite/oxalate/visible light system. The corresponding degradability was 99.5% for tetracycline, 87.1% for diethyl phthalate, and only 39.7% for glyphosate. These findings show that, whereas tetracycline and diethyl phthalate are well degraded, a major proportion of glyphosate remains adsorbed on goethite. As a consequence, glyphosate levels and toxicity may have been underestimated in previous investigations since glyphosate and glyphosate residues may be further desorbed from minerals and reenter aquatic and biological media.

To understand the content, composition and other pollution states of dissolved PCBs in the waters of coal mining subsidence area, the research object is determined as the water of Yangzhuang mining subsidence area. Seven point locations are selected there and three layers of water samples are collected in each of the point locations so as to detect and analyze PCBs with GC-MS and make sources recognition and analysis of relative factors. Results show that other PCB congeners all have been detected except PCB138 congener among the 14 detected PCBs congeners. PCBs mainly consist of trichlorodiphenyl and pentachlorodiphenyl. These two substances in each site occupy 59 to 79% of total PCBs. The pollution sources are primarily two sorts: the atmospheric transmission source and the unintended source. PCBs content has a moderate linear positive correlation with DOC and water temperature and a moderate linear negative correlation with DO. PCBs concentration is in a lower-middle level.

A large number of plastic products are used in the process of agricultural production, and the recycling efficiency is low, which leads to the production of a large number of microplastics. Therefore, the microplastic contamination in agricultural areas requires being investigated urgently. In addition, the occurrence characteristics of microplastics are also different in agricultural areas with various land use modes. In this study, the main agricultural areas in Xinjiang are taken as the research object. The abundance of microplastics in the main agricultural areas in Xinjiang ranges from 288 to 1452 items/kg. The shape of microplastics is mainly bulks, and white microplastics account for the highest proportion, and the majority of their sizes are less than 0.5 mm. The risk assessment results show that the contamination risk index of microplastics in this area is 108.92 and the risk level is grade III. The research shows that there is little difference in the abundance of microplastics between paddy field and garden land, which may be because there are few sources of microplastics in the land of these two utilization modes, and the potential pollution sources are similar, such as the atmospheric deposition of microplastics, the falling of fibers on people's clothes during farming, and the agricultural use of sludge. This study can provide a reference for further study on the existing circumstances of microplastics in agricultural areas.

Microplastics (MPs), as newly emerging pollutants, may interact with dissolved organic matter (DOM) widely present in the environment after entering the environment, thereby influencing the migration and transformation of MPs. The interaction characteristics and mechanism between DOM and MPs are restricted by many factors, and the current mechanism remains unclear. Thus, we explored the combination of MP with different types and compositions of DOM (fulvic acid (FA) and humic acid (HA)). Adsorption experiments revealed that MP has high adsorption affinity for all four DOMs, particularly FA. Meanwhile, the affinity of MP-DOM was also examined using excitation-emission matrix (EEM) analyses and fluorescence quenching method (excitation emission matrix-parallel factor analysis (EEM-PARAFAC)). Aromatic substances and hydrophobic substances dominate all DOM samples. For all DOM types tested, the quenching curve varies considerably with the type and compositions of DOM. In addition, three fluorescent components exhibited significant fluorescence quenching over time. The interaction mechanism of MPs and DOM at the molecular level was further elucidated by utilizing two-dimensional (2D) Fourier transformation infrared (FTIR) correlation spectroscopy (COS) analysis, which revealed that the oxygen-containing functional group in MPs was the most preferred DOM binding structure. This work was facilitated to explore the environmental behavior of MPs and formation of secondary MPs under natural conditions.

There are a large number of microplastic (MPs) in the sea or on land, most of which undergo physical, chemical or biological processes leading to the release of dissolved organic matter (DOM). In this study, we analyzed the change of Polyurethane microplastic (PU-MPs) valence bond under different aging conditions thanks to Fourier transform infrared spectroscopy (FTIR) and its surface characteristics using scanning electron microscopy (SEM) and also described the characteristics of DOM dissolved from PU (PU-DOM) under UV aging process in two different medium (water and air), based on Dissolved organic carbon (DOC) measurements, UV-visible spectrometer and Three-dimensional excitation emission matrices (3D-EEMs). The DOC data both showed that Under UV aging of different systems, PU-DOM concentration increases with the extension of aging time, and correspondingly, its toxicity to human colon adenocarcinoma cells also increases, but the release amount of PU-DOM under air aging is higher than that of PU-DOM in water. We speculate that it may be the refraction and scattering of water, which leads to the reduction of the intensity of UV radiation. 3D-EEMs identified tryptophan-like fluorescent component and tyrosine-like component, meanwhile, the liquid chromatography-mass spectrometer (LC-MS) data further confirmed the formation of acid substances. The results further confirmed that the composition of PU-DOM in different systems is the same, but the release amount is different. The contents of the produced conjugated carbonyls and Reactive oxygen species (ROS) because of light irradiation increased likewise. The cytotoxicity of PU-DOM was consistent with the changing trend of ROS level in PU-MPs, suggesting that the produced ROS induced the in vitro toxicities. The results not only highlight the adverse health effects of photoaged PU-MPs, but also provide new perspectives for the environmental risks of MPs.

Tetracycline (TC), a widely used antibiotic, is frequently detected in soil environments. It has a strong tendency to form complexes with metals, including iron (oxyhydr)oxide. In this study, ferrihydrite (Fh), a representative iron oxyhydroxide of the iron plaques on the surface of plant roots, was chosen to study the contributions of iron oxyhydroxide on the environmental fate of TC in the rhizosphere environment. Fh adsorption isotherm of TC showed good fitting to the Freundlich model, and the Fh adsorption capacity of TC was found much larger than the other iron oxyhydroxide of high crystallinity. The adsorption mechanisms mainly included electrostatic interaction, H-bonding, and complexation. The results of FTIR and XPS spectra revealed that tricarbonylamide, dimethylamino, and the hydroxyl in the B ring of TC were mainly responsible for the complexation with Fh surface hydroxyl groups. Furthermore, it should be noted that the adsorbed TC on Fh could be degraded and the degradation kinetics of TC better fitted to the pseudo-second-order model. Fh could promote electron transfer from TC to Fe(III) on the Fh surface, which led to the degradation of TC and the formation of Fe(II) ions. The degradation pathways of TC mainly involved three reactions: hydroxylation, dealkylation, and deamination. This study provides mechanistic insights on TC-Fh interaction, which improves the understanding of TC fate in the rhizosphere environment.

Nanoplastics (NPs), which are often detected in the natural environment, are regarded as a group of emerging pollutants. Hematite is a substance that exists widely in the surface environment and has an important impact on the environmental behavior of pollutants. Clarifying the migration of NPs requires an in-depth understanding of intrinsic interaction mechanisms of NPs with iron-containing minerals. The interaction process of polystyrene nanoplastics (PSNPs) on the hematite exposed facets was systematically studied by experiments under different conditions, adsorption isotherm curves, Fourier Transform infrared (FTIR) spectroscopy and two-dimensional correlation spectroscopy (2D-COS) analyses. We found that PSNPs were adsorbed on the three exposed faces of hematite ({001}, {012}, and {100}) by electrostatic interaction, respectively, but the capacities for PSNPs were different. Adsorption models were established to explore the preferred interaction surface dependent on the exposed facets, and it was found that {012} surfaces were more favorable for PSNPs adsorption, while {001} surface has better adsorption capacity for PSNPs than {100} surface, which is due to the different density and proportion of hydroxyl groups on the exposed facets of hematite. These findings elucidated the dependence of PSNPs adsorption on the hematite facets, and illustrated t the effect of hematite on the migration of PSNPs in the environment.

Wastewater treatment plants (WWTP) are the important source of microplastics (MPs) in the environment, but the distribution and property of MPs in WWTPs are not fully understood. The study systematically investigated the transportation, characteristics and fate of MPs in both sewage and sludge of WWTP in Xi'an, a western region of China to complement the research on the fate of MPs in WWTP in inland China. The consequence was abundance, size, shape, color and type of MPs in sewage and sludge of different treatment processes were analyzed and compared by the metallurgical microscope and Fourier Transform Infrared (FTIR) spectrometer. Results showed that the MP abundance decreased from 288.5 n/L of the influent to 22.9 n/L of the effluent, corresponding to the removal rate of 92.1%. Among them, the secondary treatment has the best removal effect, with a removal rate of 72.1%. With the treatment process, the distribution of MPs with different characteristics is constantly changing, which leads to differences in the distribution of MPs in sludge and sewage. It is speculated from the characteristics of MPs that domestic sewage is still the main source of microplastics in Beishiqiao WWTP. Restricting the use of plastic products in daily life or finding alternatives is of great significance to the construction of MPs pollution.

Microplastic (MPs) is a new type of environmental pollutant that has been widely detected in recent years. It is one of the main environmental problems faced by the global ecosystem and has attracted widespread attention. However, few studies have focused on the occurrence and distribution of MPs in agroecosystems. Therefore, Qinghai Province, a typical northwest region of China, was selected as the research area to study the distribution characteristics of MPs in agricultural soils in the low-altitude areas. The results indicated that MPs were detected in all soil samples. The abundance of MPs in agricultural soils in Qinghai Province ranged from 240 to 3660 items·kg

As an emerging pollutant, microplastics widely exist in rivers all over the world. Due to the differences of economic development, economic structure and population in different regions, the abundance of microplastics in rivers is different. In those areas where agriculture is developed, the content of film microplastics is more, while in densely populated areas, the content of fibrous microplastics is more. Taking Renhuai Basin of Chishui River as the research object, the pollution characteristics and current situation of microplastics in the basin were analyzed, and the contamination risk of microplastics was evaluated. The abundance of microplastics in Renhuai basin of Chishui River ranges from 1.77 to 14.33 items/L. The main forms of microplastics were fibrous (59.4%), white (including transparent) (41.3%) and polychromatic (44.1%). The particle size of microplastics was mainly 500– 1000 μm (63.9%). According to the assessment, the risk of microplastics in the basin is 111.79, which is a secondary risk area. This study can provide a further reference for understanding the pollution characteristics of microplastics in rivers.

Microplastics are ubiquitous in the environment, sediments in the water body are considered as the sink of microplastics, but its accumulation and change trend have received little attention. We assessed the concentrations of microplastics in sediment samples collected in Wuliangsuhai Lake. The abundance of microplastics (0–6 cm) in surface sediment ranged from 16.5 to 72.4 particles 100 g−1 dry weight. The results show that the abundance, type and size of microplastics in surface sediment of different functional areas are different. Four sampling points were selected to investigate the vertical distribution of microplastics. The abundance of microplastics exhibited a clear decreasing trend with increased sediment depth, the abundance of microplastics in deep sediments is much less. This result shows that when estimating the storage of microplastics in sediments, if only considered the surface sediments, the assessment of microplastic storage worldwide might be underestimated.

Microplastic (MP) pollution in terrestrial ecosystems has aroused great concern. However, little is known regarding the distribution of MPs in Sand Land soils and their associated destinies. We investigated the MPs pollution in different areas, different vegetation cover and restoration years in Mu Us Sand Land soils. The results clearly showed that the soils of Mu Us Sand Land contain a relatively higher MPs abundance. The significant differences of MPs abundance were demonstrated among soil from sand, grassland and woodland, which the total MP abundance of sand soil was higher than that of grassland and woodland. The distribution of MP size in the woodland area primarily from 0 to 0.50 mm, which is significantly higher than that other areas. In addition, the highest concentration of MP collected was found at Salix tree (ST), followed by Poplar tree (PT) and Chinese pine (CP), while the lowest concentration was at Pinus sylvestris (PSs) and Jujube tree (JT). It is worth noting that the abundance of MPs decreases with restoration years increased, whether it is PT or PSs. We speculate that the tree disturbance in the sampling area might affect the distribution of microplastics and then be conducive to plastic fragmentation.

Microplastics (MPs), as a new type of pollutants, have attracted wide attention especially in recent years, but there was insufficient research on the distribution and characteristics of MPs in urban park water body. In this study, the pollution of MPs in water and sediment of Xi'an, the largest city in northwest China, was investigated. The MPs concentration in the surface water and sediment was 2900–6970 items/m3 and 940–3560 items/kg, respectively. According to the urban functions, the parks were divided into residential areas, commercial areas, tourism areas and industrial areas, and the highest abundance of MPs was observed in the tourism and residential areas, suggesting the impacts of human activities. MPs in these parks were mainly in four kinds of shapes, namely fiber, pellet, fragment and film, and dominated by fibers and fragments. Most of the extracted MPs were small in size, and 63–92% of them were smaller than 0.5 mm. Polypropylene and polyethylene terephthalate were the main polymer types in surface water and sediments, respectively. This study showed that the park water and sediment can be used as an important “sink” in MPs, which is of great significance for monitoring and alleviating the pollution of urban MPs. This study provided important reference for better understanding MPs levels in inland freshwaters.

Microplastics (MPs) experienced different aging processes in environment. Literatures about effect of artificially-accelerated aging on MPs behavior are still insufficient. The accelerated process induced by ultraviolet(UV)-activated persulfate (PS) is a promising technology for obtaining different aged MPs to understand long-term aging behavior. In the work, the aging behavior of polyvinyl chloride (PVC) accelerated by UV/PS system were investigated. It exhibited a dechlorination with 58.495 ± 6.090 mg/L Cl- release after 35 h UV-activated PS (0.01 M) process. The treatment led to significant alternations on surface morphology and chemical feature of PVC. The crystallinity was increased, and average size was reduced from 154.11 µm to 119.28 µm with aging time. Subsequently, many smaller size particles were produced. Furthermore, the process induced the breaking of backbone. Simultaneously, more oxygen-containing functional groups were identified. The oxidation reaction accelerated by sulfate radical (SO4•−) and reactive oxygen species (ROS) was predominant, which immensely promoted aging process. Sustained high levels of free radical contributed to production of alcohols and carboxylic acids short chain organics. The study explored aging behavior of PVC accelerated by UV/PS system, which could be helpful for understanding environmental behavior and providing further information to assess potential risks of MPs.

In recent years, microplastics (MPs) pollution, as a global environmental problem, has been widely concerned by countries all over the world. However, the research on the impact of MPs on human health is still limited. In this study, we studied the photo-transformation behavior of polystyrene microplastics (PS-MPs) under ultraviolet light and its toxicity to Caco-2 cells. Our results showed that the surface of PS-MPs was roughened by light, and cracks and pits appeared. UV–vis spectra showed that the opening of phenyl ring and the formation of carbonyl group might exist in this process. Based on FTIR and 2D-COS analysis, we observed the formation of carbonyl group and hydroxyl group, and preliminarily determined that the order of photo-transformation of PS-MPs was 698 (C H) > 752 (C H) > 1030 (C O) > 3645 (OH/OOH) > 1740 (C O). XPS showed that the photo-transformation of PS-MPs was a process in which carbon-containing functional groups were gradually partially transformed into oxygen-containing functional groups. Finally, the toxicity results showed that with the increase of PS-MPs concentration and the extension of light irradiation time, the survival rate of Caco-2 cells gradually decreased and the integrity of cell membrane was destroyed. The increased cytotoxicity can be explained at least in part by the fact that the toxicity of oxygen-containing functional groups is greater than that of carbon-containing functional groups, but how these functional groups affect the cytotoxicity of cells still needs sustained research in the future. This study can provide new insights for understanding the environmental behavior and ecological effects of PS-MPs in the environment.

Microplastics (MPs) have attracted considerable attention due to its worldwide distribution, environmental persistence, and ecological risks. In this work, the photodegradation of MPs mediated by five different types of soils were investigated. The results showed: after 20 d of xenon lamp irradiation, significant degradation of MP was observed on Harbin (S1), Huainan (S2), Jiangxi (S3), Shaanxi (S4) and Hainan (S5). The order of photodegradation rate of MP was S2 > S5 > S4 > S1 > S3. The components of the soil have some correlations with MPs photodegradation. The photodegradation of MP mediated by soil components (specifically, the clay, the iron oxides and MnO2) displayed positive effect, while the photodegradation of MPs mediated by organic carbon showed inhibition trend. It is worth noting that electrostatic interaction may be the dominant factor affecting the interaction between MPs photodegradation rate and different soils surfaces. This study is helpful to deepen the understanding of the photochemical behavior of MP in soil, and is of great significance to evaluate the environmental fate and mechanism mediated by MP in soil.

The widespread use of glyphosate and the resulting environmental residues pose a serious threat to both crops and human health. The aim of this study was to investigate the adsorption process and removal mechanism of glyphosate by modified biochar (BC). Nano-zero-valent iron (NZVI) was loaded on the palm BC through liquid-phase chemical reduction. The composite material ((BC-NZVI)) was characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, revealing that it had a high specific surface area, rich oxygen-containing functional groups and complex ligands. Adsorption experiments were conducted with modified BC to study the effects of contact time (0–3750 min), initial concentration (5–40 mg/L), pH (2.00–7.00) and coexisting pollutants (0–20 mg/L). The adsorption data could be fitted well with the pseudo second-order kinetic model and Langmuir isotherm, indicating that the adsorption of glyphosate on the BC supported NZVI was a chemical and surface process. The maximum adsorption capacity was 80 mg/g at pH = 4, twice that of the original BC. At low concentrations, there was no influence on the adsorption of coexisting pollutants, sulfamethazine, cadmium ions, or phosphate; however, it had antagonistic effect (Rq

As a new pollutant, microplastics (MPs) exhibited more and more significant influence on the organisms in the environment. Especially, the effects on the growth and development of plants by MPs attracted wide attentions in recent period. In the review article, we summarized the important influences of MPs on terrestrial and aquatic plants. The properties, including type, size and oxygen-containing group of MPs on their physical injures toward plants were critically reviewed, which were significantly correlated to the toxicity to plants. The secondary risks of MPs including the additives and MP-derived organic products and the adsorbed environmental pollutants to plants were clearly revealed. The hydrophobic organic pollutants released from MPs showed significant chemical effects on the plants. We also outlined the effects of MPs to the various regions (e.g. the seed and rhizome) of plants and compared the toxic difference of MPs on terrestrial and aquatic plants. Generally, the seed and rhizome of plants were susceptible to MPs, and the effects of MPs on terrestrial and aquatic plants were different. The review paper improves the understanding of potential toxicity of MP themselves and the released and adsorbed chemicals to plants in the environment.

Plastics pollution in global soil systems is becoming a severely global issue and potential threat to terrestrial ecosystem serves and human health. Herein, in order to determine the degradability and ecological effects of polyethylene (PE) films, we measured the weight loss and characterization of PE films and analyzed variation in microbial community. The results of weight loss, SEM and FTIR spectra exhibited that PE films had unique degradation performance under different conditions. Simultaneously, we investigated the effects of PE films on the microbial community, and the microbiota colonizing on plastics. PE films may change the soil microbial community composition in soil, and hold the post of unique matrix for microbial colonization. These results indicate that the degradation of PE films and microbial community composition in soil can be affected by different conditions (soil layer, time and plants). By assessing the alteration of microbial community composition and PE films in soil, this work will contribute to enhance our understanding on the potential risks of plastics on soil ecosystems and provide a scientific basis for understanding the ecological effect of plastics on soil functions.

Microplastics are widespread in the environment and might transport readily by ocean currents, wind and atmospheric deposition. Simultaneously, antibiotics and heavy metals could often be detected in the environment. They are both positively charged, it is necessary to clarify the interactions of these pollutants with microplastics when they were coexist. In this study, the most commonly used polystyrene (PS) was selected as a representative microplastic. This study investigated the effect of Cd(II) on the sorption of TYL by PS in different coexistence systems. The results showed that: in the composite system, when TYL and Cd(II) coexist, the presence of Cd(II) could inhibit the sorption of TYL by PS, and the inhibitory effect increases with the increase of the concentration of Cd(II), indicating that competitive sorption dominates the sorption. When PS adsorbed Cd(II) first and then adsorbed TYL, the presence of Cd(II) was conducive to the sorption of TYL, and the sorption strengthened with the increase of Cd(II) concentration, indicating that the complexation between TYL and Cd(II) enhanced the sorption of TYL. In addition, initial pH values and ionic strength were essential in the sorption process. Therefore, this study could provide an important basis for evaluating the environmental behavior and ecological risk of microplastics in the process of compound pollution.

Sulfamethazine (SMT), taken as model compound, have been exposed to a photocatalytic system driven by ultraviolet light (UV) irradiation with Fe(III) and three carboxylic acids (citric, tartaric and malic acid). The kinetic experiments, quenching experiments, electron paramagnetic resonance (EPR), species model theoretical calculation, density functional theory (DFT) and intermediates analyses, were conducted to analyze the formation of reactive oxygen species (ROS) and underlying mechanism of Fe(III)-carboxylate complexes on photocatalytic degradation of SMT. The results indicated the complexes easily induced the degradation under UV irradiation. Enough hydroxyl radicals (·OH) were produced and the singlet oxygen (1O2) originated from the self-sensitized oxidation. An interaction among ROS, Fe(III)-carboxylate complexes and SMT was firstly proposed. The active sites and groups were characterized through Frontier electron densities (FEDs), Fourier Transform-Infrared (FTIR) and Two-dimensional correlation FTIR spectroscopy (2D-FTIR-CoS) analyses. The transformation pathway mainly included four reactions: hydroxylation, SO2 extrusion, Smiles-type rearrangement and S-N bond cleavage. The system also had an application potential for removing SMT from practical water.

To probe into the concentration, composition and other pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of coal mining subsidence water, Yangzhuang coal mining subsidence waters in Panyi Mine of China are determined as the object of this research, where 11 surface sediment samples are collected to detect and analyze PAHs with a Gas Chromatography-Mass Spectrometer (GC-MS) and make source apportionment with factor analysis and ecological risk assessment. The results show that 16 kinds of PAHs have all been detected, with the content level of ∑PAHs reaching 55 to 755 ng g−1 and the average content of that reaching 288 ng g−1. PAHs with three or four rings dominate. The pollution level of PAHs is quite low and mostly comes from combustion and oil. Most of these 16 kinds of PAHs have been proved to be of no potential ecological risk.

Tetracycline (TC) and chromate (Cr(VI)) are common organic or inorganic pollutants in the environment, and the interactions between them may mutually alter environmental behaviors and risks. However, the mutual effect between TC and Cr(VI) in aqueous solutions remains unclear. In this study, kinetic experiments, complexation and quenching experiments, electron spin resonance (ESR) analysis, density functional theory (DFT) calculation and identification of products, were performed to investigate the effects and underlying mechanism of Cr(VI) on oxidation and photolysis of TC. The results revealed that Cr(VI) could induce oxidation and photolysis of TC with or without light irradiation and the curve was well fitted by a pseudo first-order kinetic model. Moreover, the change of reaction conditions (such as initial concentration and pH) had great effect on oxidation or photolysis of TC. When Cr(VI) oxidized TC to form Cr(III) and TC radical, Cr(III) complexed with TC to accelerate the oxidation. In addition, oxidation still occurred under simulated irradiation. 1O2 which promoted photolysis of TC increased upon irradiation at higher pH or with the increase of Cr(VI). The participation of Cr(VI) affected self-sensitization and product formation of TC. Therefore, an electron-transfer interaction for photolysis among 1O2 arising from self-sensitization, Cr(VI)/Cr(III) and TC was first proposed. The transformation pathway of TC mainly included five reactions: hydrolysis, hydroxylation, deamination, dehydration and demethylation only for photolysis. This study identified new oxidation and photolysis of TC induced by Cr(VI), which will be helpful to further understand the fate of heavy metals and antibiotics in the natural aquatic environment.

The coal mining subsidence area in Huainan is a specific but common ecosystem in China. Not a lot of researches focusing on persistent organic pollutants like polycyclic aromatic hydrocarbons (PAHs) in this area have been done. In order to investigate the concentrations, sources, environmental fate of PAHs and its distribution factors, Yangzhuang and Xieqiao coal mining subsidence areas in Huainan, China were determined as the object of the research, where samples from different depths of soil and sediments were collected to detect and analyze PAHs with Gas Chromatography-Mass Spectrometry. The result showed that the 16 PAH compounds were all detected with a detection rate of 100%. The concentrations of PAHs at different depths of the soil and sediments of Yangzhuang were in the range of 42.1–22149.0 and 44.0–7644.2 ng/g, respectively, and in Xieqiao which were in the range of 17.8–1617.7 and 35.7–264.6 ng/g, respectively. Through comparing the results about spatial interpolation analyses of two subsidence areas, we found that PAHs pollution in soil was heavier than that in sediments of the subsidence areas with relatively small man-made interference. Man-made pollution had a great influence on the vertical distribution of PAHs in the subsidence areas. The PAHs with three or four rings dominated in the areas. Using diagnostic ratios, we found PAHs came from mixed pollutions including the combustion of coal and traffic pollution. As for the influence factors, based on regression analysis and Pearson correlation analysis, the increase of organic matters (OM) and total organic carbon (TOC) favored the deposition of PAHs and had a positive impact on the vertical distribution of PAHs.