Publications by authors named "Beidou Xi"

160 Publications

Fate of antibiotic resistance genes in industrial-scale rapid composting of pharmaceutical fermentation residue: The role implications of microbial community structure and mobile genetic elements.

Environ Pollut 2021 Sep 13;291:118155. Epub 2021 Sep 13.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Innovation Base of Ground Water & Environmental System Engineering, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

Composting is an effective technology to recycle organic solid waste as a green resource. However, pharmaceutical fermentation residue (PFR) contains a variety of pollutants, such as residual drug and antibiotic resistance genes (ARGs), which limits the green cycle of using PFR as a resource. To promote the green recycling of PFR, this study evaluated the characteristics of abundance and the response relationship of ARGs during the process of rapid composting. Different rapid composting samples were collected, and DNA was extracted from each sample. The absolute abundance of ARGs was quantified using quantitative PCR, and the microbial community structure was identified using high-throughput sequencing. The results showed that ermB, ermF, tetM and tetQ were reduced by 89.55%, 15.10%, 89.55%, and 82.30% respectively, and only sul2 increased by approximately 5-fold. Mobile genetic elements (MGEs) directly affected the changes in abundance of ARGs. As typical MGEs, intl1 and intl2 decreased by 3.40% and 54.32%, respectively. Potential host microorganisms important factors that affected ARGs and MGEs. A network analysis indicated that the potential host microorganisms were primarily distributed in Firmicutes and Proteobacteria at the phylum level. The pH and content of water-extractable sulfur were physicochemical parameters that substantially affected the abundance of potential host microorganisms through redundancy analysis. Industrial-scale rapid composting could reduce the number of ARGs and shorten the composting cycle, which merits its popularization and application.
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http://dx.doi.org/10.1016/j.envpol.2021.118155DOI Listing
September 2021

Efficient mineralization of TBBPA via an integrated photocatalytic reduction/oxidation process mediated by MoS/SnInS photocatalyst.

Chemosphere 2021 Jul 13;285:131542. Epub 2021 Jul 13.

Indoor Environment Engineering Research Center of Fujian Province, Fujian University of Technology, Fuzhou, 350118, China. Electronic address:

Currently, Tetrabromobisphenol A (TBBPA) has been regarded as an emerging organic pollutant and efficient TBBPA elimination technology has been attracting increasing attention. In this work, a novel photocatalyst, MoS/SnInS, was synthesized through hydrothermal method by introducing few-layer MoS nanosheets and then employed to establish an integrated photocatalytic reduction/oxidation system for the remediation of TBBPA under visible light. The characterization results demonstrated that the few-layer MoS nanosheets were well combined with SnInS and significantly lowered the recombination rate of the photo-induced electron and holes, leading to outstanding photocatalytic performance of MoS/SnInS composite. Besides, the MoS/SnInS composite also exhibited excellent reusability (over 10 runs) and stability. The TBBPA degradation experiments showed that the integrated photocatalytic reduction/oxidation system was able to completely degrade TBBPA and mineralize its byproducts (60.2 ± 2.9%). In the photocatalytic reduction, due to the cleavage of C-Br bonds by photo-induced electrons, TBBPA underwent stepwise debromination and finally transferred into BPA in 6 h. In the following photocatalytic oxidation, under the attack of reactive oxygen species (O, h,OH and O), BPA was first decomposed into aromatic products (such as phenol, benzoic acid, p-hydroxybenzyl alcohol and so on) via C-C bond cracking and hydroxylation, and then further oxidized into organic acids like maleic acid and muconic acid through ring-opening, and finally mineralized into CO and HO. What was noteworthy was that the final effluent from the photocatalytic reduction/oxidation system showed no toxicity to the luminescent bacteria.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131542DOI Listing
July 2021

Release, transformation, and risk factors of polybrominated diphenyl ethers from landfills to the surrounding environments: A review.

Environ Int 2021 Jul 24;157:106780. Epub 2021 Jul 24.

State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

Polybrominated diphenyl ethers (PBDEs) serve as brominated flame retardants when added to various products. When these products reach their end of life, a large amount of domestic waste containing PBDEs enters the landfills. Given their weak chemical bonds, they are easily affected by physical, chemical, and biological processes. These processes result in their release and the subsequent contamination of the surrounding soil, groundwater, and atmosphere, causing harm to humans and ecosystems. However, despite the progress made in the research of PBDEs over the years, understanding of the environmental behavior and fate of pollutants is still limited. With the development of cities, the release of PBDEs in old landfills will gradually increase the risk to the surrounding environment. Here we review the biological and nonbiological transformation of PBDEs and their derivatives in landfills and surrounding areas, as well as their distribution in soil, groundwater, and atmosphere. Specifically, this review aims to provide insights into the following aspects: 1) the biological (plant, animal, and microbial) and nonbiological (metal catalysis and photodegradation) conversion of PBDEs and their derivatives in landfills and surrounding areas; 2) the distribution of landfill-sourced PBDEs in the soil, groundwater, atmosphere and cross-media migration; and 3) suggestions and future research directions for the management and control of PBDEs in landfills.
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http://dx.doi.org/10.1016/j.envint.2021.106780DOI Listing
July 2021

Anaerobic digestion of chicken manure: Sequences of chemical structures in dissolved organic matter and its effect on acetic acid production.

J Environ Manage 2021 Oct 12;296:113245. Epub 2021 Jul 12.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address:

The use of chicken manure (CM) leads to serious environmental pollution due to the existence of bacteria and insect pests. Anaerobic digestion (AD) is one of the important technologies of CM treatment. However, methane production is limited by the accumulation of short-chain fatty acids (SCFAs) from AD. Therefore, the study explored the possible formation mechanism of acetic acid by understanding the effect of sequences of chemical structure variation in DOM on acetic acid production. The chemical structures of DOM were observed. The tyrosine-like substances (C1, 53.53-29.99%) and humic-like substances (C3, 18.38-5.96%) showed a tendency to decrease. Tryptophan-like substances (C2, 28.09-64.04%) showed the increasing trend. The results indicated that C2 was unwilling to biodegrade. In DOM, the order of biodegradability was C2< C1< C3. AD resulted in the enrichment of N-H in-plane (0-22.75%) and COO- stretch (7.53-18.57%) and the loss of O-H stretch (19.39-13.72%), C-H stretch (4.56%-0), CC stretch (12.04-9.61%) and C-O stretch (10.02-5.03%). Two-dimensional correlation spectroscopy is applied to investigate the sequences of chemical structures in DOM, the order is as follows: CC stretch > COO- stretch > N-H in-plane > C-O stretch. The result confirmed that protein was rapidly decomposed and utilized, which would result in the increase of microorganism metabolism and hydrolysis rate, polysaccharide was hydrolyzed to form phenol and carboxylic acid. Four possible pathways were identified in AD by the structural equation model. C1and hydroxyl can promote propionic and butyric acid formation by the pathway of valeric or iso-butyric acid production and further effected acetic acid production. This study proposed the possible formative mechanisms of acetic acid according to sequences of chemical structures variation in DOM during AD, which can provide the theoretical basis for directional regulating the conversion of different chemical structures of DOM into acetic acid in AD.
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http://dx.doi.org/10.1016/j.jenvman.2021.113245DOI Listing
October 2021

Effects of microplastics on soil organic carbon and greenhouse gas emissions in the context of straw incorporation: A comparison with different types of soil.

Environ Pollut 2021 Jul 8;288:117733. Epub 2021 Jul 8.

State Key Laboratory of Environmental Criteria and Risk Assessment, And State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

Plastic mulching and straw incorporation are common agricultural practices in China. Plastic mulching is suspected to be a significant source of microplastics in terrestrial environments. Straw incorporation has many effects on the storage of soil organic carbon (SOC) and greenhouse gas emissions, but these effects have not been studied in the presence of microplastic pollution. In this study, 365-day soil incubation experiments were conducted to assess the effects of maize straw and polyethylene microplastics on SOC fractions and carbon dioxide (CO) and nitrous oxide (NO) emissions in two different soils (fluvo-aquic and latosol). Against the background of straw incorporation, microplastics reduced the mineralization and decomposition of SOC, resulting in a microbially available SOC content decrease by 18.9%. In addition, microplastics were carbon-rich, but relatively stable and difficult to be used by microorganisms, thus increasing the mineral-associated SOC content by 52.5%. This indicated that microplastics had adverse effects on microbially available SOC and positive effects on mineral-associated SOC. Microplastics also decreased coarse particulate SOC (>250 μm), and increased non-aggregated silt and clay aggregated SOC (<53 μm). Furthermore, microplastics changed microbial community compositions, thereby reducing the CO and NO emissions of straw incorporation by 26.5%-33.9% and 35.4%-39.7%, respectively. These results showed that microplastics partially offset the increase of CO and NO emissions induced by straw incorporation. Additionally, the inhibitory effect of microplastics on CO emissions in fluvo-aquic soil was lower than that in latosol soil, whereas the inhibitory effect on NO emissions had the opposite trend.
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http://dx.doi.org/10.1016/j.envpol.2021.117733DOI Listing
July 2021

Key factors driving the fate of antibiotic resistance genes and controlling strategies during aerobic composting of animal manure: A review.

Sci Total Environ 2021 Oct 8;791:148372. Epub 2021 Jun 8.

School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address:

Occurrence of antibiotic resistance genes (ARGs) in animal manure impedes the reutilization of manure resources. Aerobic composting is potentially effective method for resource disposal of animal manure, but the fate of ARGs during composting is complicated due to the various material sources and different operating conditions. This review concentrates on the biotic and abiotic factors influencing the variation of ARGs in composting and their potential mechanisms. The dynamic variations of biotic factors, including bacterial community, mobile genetic elements (MGEs) and existence forms of ARGs, are the direct driving factors of the fate of ARGs during composting. However, most key abiotic indicators, including pH, moisture content, antibiotics and heavy metals, interfere with the richness of ARGs indirectly by influencing the succession of bacterial community and abundance of MGEs. The effect of temperature on ARGs depends on whether the ARGs are intracellular or extracellular, which should be paid more attention. The emergence of various controlling strategies renders the composting products safer. Four potential removal mechanisms of ARGs in different controlling strategies have been concluded, encompassing the attenuation of selective/co-selective pressure on ARGs, killing the potential host bacteria of ARGs, reshaping the structure of bacterial community and reducing the cell-to-cell contact of bacteria. With the effective control of ARGs, aerobic composting is suggested to be a sustainable and promising approach to treat animal manure.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148372DOI Listing
October 2021

Effects of sulfur-rich biochar amendment on microbial methylation of mercury in rhizosphere paddy soil and methylmercury accumulation in rice.

Environ Pollut 2021 Oct 3;286:117290. Epub 2021 May 3.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

Biochar amendment has the potential to reduce methylmercury (MeHg) uptake by rice grains in soil-rice ecosystem. Considering that sulfur can strongly bind Hg and thus reduce its bioavailability, S-modified biochar has been used to immobilize Hg in soils. However, whether natural S-enriched biochar can further reduce Hg and MeHg phytoavailability remains unknown. Moreover, the rhizosphere is one of the most important microbial hotspots regulating the pollutant dynamics in terrestrial ecosystems. Therefore, it is of greater practical significance to examine the impact of biochar amendment on MeHg production and phytoavailability in the rhizosphere versus nonrhizosphere. Here, by conducting a pot experiment, we evaluated the efficacy of biochar derived from sulfur-enriched oilseed rape straw to reduce MeHg accumulation in rice. The results demonstrated that: (1) biochar-induced enhancement of chloride ion and sulfate levels in the overlying water and pore water facilitate microbial methylation of Hg and thus MeHg production in rhizosphere soil. (2) biochar amendment increased rhizosphere soil sulfur content and humic acid-like substances, strengthening MeHg binding to soil, and thus reducing grain MeHg levels by 47%-75%. Our results highlight the necessity to applying natural sulfur-rich biochar accompanied with exogenous sulfur to further reduce MeHg phytoavailability.
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http://dx.doi.org/10.1016/j.envpol.2021.117290DOI Listing
October 2021

Classification technology of domestic waste from 2000 to 2019: a bibliometrics-based review.

Environ Sci Pollut Res Int 2021 Jun 5;28(21):26313-26324. Epub 2021 Apr 5.

State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.

Waste classification is to reduce solid waste and its associated environmental pollution. This paper applied bibliometrics to assess publications related to classification technology of domestic waste from 2000 to 2019. A total of 466 publications were retrieved. The results showed the number of citations and papers increased rapidly. The major publication type regarding waste classification technology is article and English is the primary language for academic communication. The research is multidisciplinary and interdisciplinary, and its research directions are mainly divided into "Engineering," "Environmental Sciences Economics," and "Chemistry." It was identified that Waste Management (85) published most of papers in this topic. Meanwhile, China (93) contributed the most of publications, followed by the USA (42), France (40), Japan (36), and Italy (28). European countries are in the leading position in the study of garbage classification technology. Plastics and waste metals were the existing focus of waste classification technology, and waste identification and classification has become an important classification method. In addition, we also summarized the current mainstream technology progress and possible research challenges.
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http://dx.doi.org/10.1007/s11356-021-12816-xDOI Listing
June 2021

Untangling the response of fungal community structure, composition and function in soil aggregate fractions to food waste compost addition.

Sci Total Environ 2021 May 20;769:145248. Epub 2021 Jan 20.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address:

Soil fungi are key drivers in regulating the ecosystem function, playing a vital role in protecting the plant from phytopathogens and other biotic and abiotic pressures. However, the potential impact of compost addition and soil aggregate size on the fungal community and functional ecological guild remains uncertain. This study investigated the structure, composition, and function of soil fungal communities across aggregate fractions under food waste compost addition using Miseq sequencing and FUNGuild. Compost addition exerted a negative impact on fungal α-diversity, and shifted the structure and changed the composition of fungal community. Compost addition rates exhibited more contributions to fungal α-diversity variations (R = 0.609, 0.895, and 0.501 for Sobs, Shannon, and Chao indices, respectively, P = 0.001) and the separation of community structure than soil aggregate size (R = 0.952, P = 0.001). Biomarkers, including Chaetomiaceae, Ascobolaceae, and Sordariomycete, displayed significant superiority in compost-added soils, whereas the populations of Nectriaceae and Clavicipitaceae were significantly decreased. The relative abundances of animal and plant pathogens were significantly decreased, whereas that of saprotrophs were increased. The abundances of pathogens correlated positively with pH and negatively with nutrients (soil organic matter, dissolved organic carbon, total nitrigen, NH, and NO), whereas those of saprotrophs showed an opposite trend. The dose of compost was the major driver for fungal functional guild variation, whereas carbon and nitrogen source exhibited more contributions to function variation than pH value. These results provide a reference for sustainable ecological agriculture by applying compost rationally under the conditions of soil health and agricultural performance.
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http://dx.doi.org/10.1016/j.scitotenv.2021.145248DOI Listing
May 2021

Perdisulfate-assisted advanced oxidation of 2,4-dichlorophenol by bio-inspired iron encapsulated biochar catalyst.

J Colloid Interface Sci 2021 Jun 20;592:358-370. Epub 2021 Feb 20.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.

To improve advanced oxidation processes (AOPs), bio-inspired iron-encapsulated biochar (bio-inspired Fe⨀BC) catalysts with superior performance were prepared from iron-rich biomass of Iris sibirica L. using a pyrolysis method under anaerobic condition. The obtained compounds were used as catalysts to activate perdisulfate (PDS) and then degradate 2,4-dichlorophenol (2,4-DCP), and synthetic iron-laden biochar (synthetic Fe-BC) was used for comparison. The highest removal rate of 2,4-DCP was 98.35%, with 37.03% of this being distinguished as the contribution of micro-electrolysis, greater than the contribution of adsorption (32.81%) or advanced oxidation (28.51%). The high performance of micro-electrolysis could be attributable to the formation of Fe (Iron, syn) and austenite (CFe) with strong electron carrier at 700 °C. During micro-electrolysis, Fe and electrons were gradually released and then used as essential active components to enhance the AOPs. The slow-releasing Fe (K = 0.0048) also inhibited the overconsumption of PDS (K = -0.00056). Furthermore, the electrons donated from Fe⨀BC-4 were able to activate PDS directly. The electrons were enriched by the porous structure of Fe⨀BC-4, and the formation of the COFe bond in the π-electron system could also accelerate the electron transfer to activate PDS. Similar reactive oxygen species (ROS) were identified during the micro-electrolysis and AOPs, leading to similar degradation pathways. The higher does concentration of O generated during micro-electrolysis than during the AOPs also led to a greater dechlorination effect.
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http://dx.doi.org/10.1016/j.jcis.2021.02.056DOI Listing
June 2021

Divergent response of heavy metal bioavailability in soil rhizosphere to agricultural land use change from paddy fields to various drylands.

Environ Sci Process Impacts 2021 Mar 2;23(3):417-428. Epub 2021 Mar 2.

State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

The heavy metal pollution induced by agricultural land use change has attracted great attention. In this study, the divergent response of the bioavailability of heavy metals in rhizosphere soil to different agricultural land uses was analyzed using sequential extraction, and possible influence paths were constructed. The results show that land use change can affect the heavy metal bioavailability by influencing the soil organic matter and redox potential (Eh). The average concentrations of N, P, K, Ca, Mg, S, and Fe in the soil showed no significant differences. However, the conversion direction and extent of chemical speciation of heavy metals were different across land use changes from paddy fields to various drylands. After conversion from paddy to wheat field, the bioavailability of heavy metals decreased due to an increase in permanganate oxidizable carbon (KMnO-C) and a decrease in Eh. The transformation from paddy to celery soil is accompanied by a change in the soil's KMnO-C content, increasing the proportion of the bioavailable states of heavy metals. However, the response of bioavailability to changes in the soil KMnO-C varied among heavy metals. In contrast, when land use changed to grapevine culture, the bioavailability of heavy metals increased due to a change in the KMnO-C content. Moreover, the dissolved organic carbon (DOC) content increased, which positively affected the Eh and, in turn, increased the bioavailability of heavy metals. This research is of great significance for understanding the impact of land use change on the heavy metal migration and activity in the rhizosphere microenvironment of soil.
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http://dx.doi.org/10.1039/d0em00501kDOI Listing
March 2021

Transport and retention of porous silicon-coated zero-valent iron in saturated porous media.

Environ Pollut 2021 May 9;276:116700. Epub 2021 Feb 9.

Key Lab of Groundwater Resources and Environment Ministry of Education, Jilin University, Changchun, 130026, PR China.

Porous silicon-coated zero-valent iron ([email protected]) is a promising material for in-situ contaminated groundwater remediation. However, investigations of factors that affect the transport of [email protected] remain incomplete. In the present study, [email protected] composites were prepared by a SiO-coated technology, and a series of column experiments were conducted to examine the effects of media size, ionic strength, and injection velocity and concentration on retention and transport in saturated porous media. Results showed that the obtained [email protected] is a core-shell composite with zero-valent iron as the core and porous silicon as the shell. Media size, injection velocity, Fe concentration, and ionic strength had a significant impact on the transport of [email protected] [email protected] effluent concentrations decreased with a smaller media size. Increasing initial particle concentration and ionic strength led to a decrease in particle transport. High particle retention was observed near the middle of the column, especially with high injection concentration. That was also observable in the condition of lower injection velocity or finer media. The results indicated that two transport behaviors during particles transport, which were "agglomeration-straining" and "detachment-re-migration". Moreover, the dominated mechanisms for [email protected] transport and retention in saturated porous media are hydrodynamic dispersion and interception. Given the results, in practical engineering applications, proper injection velocity and concentration should be selected depending on the pollution status of groundwater and the geochemical environment to ensure an effective in-situ reaction zone.
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http://dx.doi.org/10.1016/j.envpol.2021.116700DOI Listing
May 2021

Effect of water-level fluctuation on the removal of benzene from soil by SVE.

Chemosphere 2021 Jul 28;274:129796. Epub 2021 Jan 28.

State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

In areas that experience frequent fluctuations in groundwater levels, changes in soil void space caused by fluctuations in groundwater levels directly affect the efficacy of soil vapor extraction (SVE). Most studies of SVE technology of oil-contaminated soil remediation do not consider fluctuations in groundwater levels. Here, we constructed an experimental device to study the removal of benzene by SVE under fluctuating groundwater levels. Key parameters affecting the remediation effect of SVE, such as the extraction flow, extraction time, extraction method, initial soil moisture content and initial pollutant content, were studied to characterize their effects on the efficacy of benzene removal by SVE under stable and fluctuating groundwater levels. The removal rate of benzene by SVE was approximately 10% higher under fluctuating water levels than under stable water levels. Extraction flow can directly change the removal rate under fluctuating groundwater levels. Under fluctuating groundwater levels, the removal effect of SVE on benzene in different soils of the "stabilization zone - fluctuation zone - saturation zone" also significantly differed; specifically, the removal effect of SVE in the fluctuation zone and stabilization zone was superior to that in the saturation zone. Given the fluctuation in groundwater levels at the study site, the remediation.
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http://dx.doi.org/10.1016/j.chemosphere.2021.129796DOI Listing
July 2021

Comparing the long-term responses of soil microbial structures and diversities to polyethylene microplastics in different aggregate fractions.

Environ Int 2021 04 24;149:106398. Epub 2021 Jan 24.

State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.

Microplastics (MPs) alter soil aggregation stability. However, studies have yet to determine whether these alterations further affect microbial community structures and diversities within different soil aggregates and whether they influence the responses of soil microbial structures and diversities to MPs in different aggregate fractions. In this study, long-term soil incubation experiments and soil fractionation were combined to investigate the effects of polyethylene microplastics (PE-MPs) on soil aggregate properties and microbial communities in soil aggregates with different particle sizes. Results showed that the existence of PE-MPs significantly reduced the physicochemical properties of soil aggregates, inhibited the activities of soil enzymes, and changed the richness and diversity of bacterial and fungal communities. Such variations exerted notable differences in soil aggregate levels. The response sensitivity of bacteria in the silt and clay fraction was higher than that in the macroaggregate fraction, but the response sensitivity of fungi in the macroaggregate fraction was higher than that in the silt and clay fraction. Relationships and path analysis between soil aggregate properties and microbial communities after PE-MPs addition were proposed. PE-MPs affected microbial community structures by directly and indirectly influencing soil microenvironmental conditions. The relative abundances of Acidobacteria, Gemmatimonadetes, Bacteroides, Basidiomycota, Chtridiomyota, and Glomeromycota were significantly correlated with physicochemical properties and soil enzyme activities. Enzyme activities were direct factors influencing soil microbial community structures, and physicochemical properties (i.e., dissolved organic carbon, soil available phosphorus) could indirectly affect these structures by acting on soil enzyme activities. Our findings helped improve our understanding of the responses of soil microbial structures and diversities to MPs through the perspective of different soil aggregates.
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http://dx.doi.org/10.1016/j.envint.2021.106398DOI Listing
April 2021

Heavy metal pollution, ecological risk, spatial distribution, and source identification in sediments of the Lijiang River, China.

Environ Pollut 2021 Jan 30;269:116189. Epub 2020 Nov 30.

College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541004, PR China.

The Lijiang River is of great ecological and environmental importance for Guilin City, which is located in the karst area of southeast China. Given its importance, a detailed evaluation of the heavy metals (HMs) in the river sediment is required. For the first time, 61 sediment samples were collected along the entire Lijiang River to determine pollution level and ecological risk posed by 10 HMs (Co, Cr, Cu, Mn, Ni, Pb, Zn, As, Hg, and Cd). These were assessed using the geo-accumulation index, potential ecological risk index, and modified degree of contamination. The results showed that the mean concentrations of the majority of HMs exceeded their corresponding background values and followed the trend: midstream > downstream > upstream. Based on the spatial distributions and pollution indices of the 10 HMs, the Lijiang River was found to have a high accumulation of Cd, Hg, Zn, and Pb in the sediments. The midstream area was the most polluted with respect to Cd and Hg, and also posed a relatively higher potential ecological risk than the downstream and upstream areas. The sources of the assessed HMs were inferred based on a correlation analysis and principal component analysis, which identified both natural and anthropogenic sources. A higher pollution potential was associated with Cd, Hg, Pb, and Zn in the midstream and downstream areas due to higher organic and carbonate content, urbanization, agricultural activities, and leisure activities (e.g., boating and cruises). In contrast, natural erosion and weathering processes were responsible for the HM concentrations in the upstream area. The findings of this study will help the local authorities to protect the important water resource of the Lijiang River.
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http://dx.doi.org/10.1016/j.envpol.2020.116189DOI Listing
January 2021

Insights into the effects of heavy metal pressure driven by long-term treated wastewater irrigation on bacterial communities and nitrogen-transforming genes along vertical soil profiles.

J Hazard Mater 2021 02 2;403:123853. Epub 2020 Sep 2.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

Irrigation with treated wastewater (TWW) influences soil ecological function due to the accumulation of heavy metals (HMs) and nutrients in soils. However, the interaction between HMs and microbial processes in TWW-irrigated soil has not been fully explored. We investigated the effect of HMs on bacterial communities and nitrogen-transforming (N-transforming) genes along vertical soil profiles irrigated with domestic TWW (DTWW) and industrial TWW (ITWW) for more than 30 years. Results indicate that long-term TWW irrigation reshaped bacterial community structure and composition. Irrigation with ITWW led to increased accumulation of Cd, Cr, Cu, Pb, Zn, and Ni in soils than DTWW. Accumulation of inorganic N, soil organic carbon, and HMs in topsoil irrigated with ITWW contributed to the activities of Micrococcaceae. The effect of the activation of nutrient factors on Bacillus, which was the dominant species in DTWW-irrigated soils, was greater than that of HMs. HM pressure driven by ITWW irrigation changed the vertical distribution of N-transforming functional genes, increasing the abundance of amoA gene and decreasing that of nifH through soil depth. ITWW irrigation enhanced the denitrification capacity in topsoil; ammonia-oxidizing capacity in deeper soil was increased after long-term irrigation with DTWW and ITWW, suggesting a potential risk of nitrogen loss.
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http://dx.doi.org/10.1016/j.jhazmat.2020.123853DOI Listing
February 2021

The cotreatment of old landfill leachate and domestic sewage in rural areas by deep subsurface wastewater infiltration system (SWIS): Performance and bacterial community.

Environ Pollut 2021 Apr 12;274:115800. Epub 2020 Oct 12.

State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

In this work, two deep subsurface wastewater infiltration systems (SWISs) were constructed and fed with domestic sewage (control system, S1) and mixed wastewater consisting of old landfill leachate and domestic sewage (experimental system, S2). S1 and S2 exhibited favorable removal efficiencies, with TP (98.8%, 98.7%), COD (87.6%, 86.9%), NH-N (99.8%, 99.9%) and TN (99.2%, 98.9%). Even when increasing the pollutant load in S2 by adding old landfill leachate, the almost complete removal performance could be maintained in terms of low effluent concentrations and even increased in terms of load removal capabilities, which included COD (19.4, 25.9 g∙m·d), NH-N (8.2, 19.9 g∙m·d), TN (8.9, 20.6 g∙m·d). To investigate the transformation of dissolved organic matter along depth, Three-Dimensional Excitation Emission Matrix fluorescence spectroscopy combined with Fluorescence Regional Integration analysis was applied. The results showed that P and P (the proportions of biodegradable fractions) increased gradually from 6.59% to 21.8% at S2_20 to 10.8% and 27.7% at S2_110, but P and P (the proportions of refractory organics) declined from 23.1% to 27.8% at S2_20 to 21.1% and 16.4% at S2_110, respectively. In addition, high-throughput sequencing technology was employed to observe the bacterial community at different depths, and the predicted functional potential of the bacterial community was analyzed by PICRUSt. The results showed that the genera Flavobacterium, Pseudomonas, Vogesella, Acinetobacter and Aquabacterium might be responsible for refractory organic degradation and that their products might serve as the carbon source for denitrifiers to achieve simultaneous nitrate and refractory organic removal. PICRUSt further demonstrated that there was a mutual response between refractory organic degradation and denitrification. Overall, the combined treatment of domestic sewage and old leachate in rural areas by SWIS is a promising approach to achieve comprehensive treatment.
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http://dx.doi.org/10.1016/j.envpol.2020.115800DOI Listing
April 2021

Characterization of hydrogen production and microbial community shifts in microbial electrolysis cells with L-cysteine.

Sci Total Environ 2021 Mar 29;760:143353. Epub 2020 Oct 29.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

L-cysteine is used to improve efficiency in anaerobic biological systems as an oxygen scavenger, electron shuttle and substrate source. The performance of MEC by addition of L-cysteine was investigated during start-up and operation phases, respectively. Results showed that the maximum current density of 6.36 ± 0.14 A/m, hydrogen yield of 1.08 ± 0.05 m/m and energy efficiency of 130% were achieved with L-cysteine adding during operation phase. By contrast, the addition of L-cysteine during the start-up phase reduced the energy efficiency by more than 30%. The microbial community analysis revealed that a higher microbial community richness and diversity were achieved, the enrichment of Sulfuricurvum, Sulfurospirillum, Desulfovibrio and other electroactive microorganisms indicated their relative abundance could be regulated by L-cysteine during start-up phase when L-cysteine was added. This study provided an alternative method to enhanced hydrogen production and a better understanding of the mechanism of L-cysteine action in MEC performance.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143353DOI Listing
March 2021

The maturity period is the main stage of antibiotic resistance genes reduction in aerobic composting process of swine manure in sub-scale farms.

Bioresour Technol 2021 Jan 17;319:124139. Epub 2020 Sep 17.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

This study was focused on the changes of antibiotic resistance genes (ARGs) and their potential host bacteria during the swine manure composting on sub-scale farms. Eight target ARGs increased 427% on average, with a trend of increase at early stage and decrease at later stage, and the main reduction stage appeared in maturity stage. The abundance of ARGs was mainly affected by the community succession of potential host bacteria. Composting could reduce the abundance of potential host bacteria of ARGs as well as pathogens such as Pseudomonas, and reduce the environmental risks of swine manure. N/C and S levels had a positive effect on the potential host of most ARGs. Prolonging the maturity period would inhibit the growth of potential host bacteria of ARGs during composting, therefore inhibiting the transmission of ARGs.
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http://dx.doi.org/10.1016/j.biortech.2020.124139DOI Listing
January 2021

Inhibitory effect of microplastics on soil extracellular enzymatic activities by changing soil properties and direct adsorption: An investigation at the aggregate-fraction level.

Environ Pollut 2020 Dec 28;267:115544. Epub 2020 Aug 28.

State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

Microplastics (MPs), as a new type of environmental pollutant, pose a serious threat to soil ecosystems. The activities of soil extracellular enzymes produced by microorganisms are the potential sensitive indicators of soil quality. However, little is known about the response mechanism of enzyme activities toward MPs on a long-term scale. Moreover, information on differences in enzyme activities across different soil aggregates is lacking. In this study, 150 days of incubation experiments and soil aggregate fractionation were combined to investigate the influence of MPs on extracellular enzyme activities in soil. 28% concentration of polyethylene with size 100 μm was adopted in the treatments added with MPs. The results show that MPs inhibited enzyme activities through changing soil nutritional substrates and physicochemical properties or through adsorption. Moreover, MPs competed with soil microorganisms for physicochemical niches to reduce microbial activity and eventually, extracellular enzyme activity. Enzyme activities in different aggregate-size fractions responded differently to the MPs exposure. The catalase in the coarse particulate fraction and phenol oxidase and β-glucosidase in the micro-aggregate fraction exerted the greatest response. With comparison, urease, manganese peroxidase, and laccase activities showed the greatest responses in the non-aggregated silt and clay fraction. These observations are believed to stem from differences in the key factors determining the enzyme activities in different aggregate-size fractions. The inhibitory pathway of microplastics on activities of extracellular enzymes in soil varies significantly across different aggregate fractions.
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http://dx.doi.org/10.1016/j.envpol.2020.115544DOI Listing
December 2020

Metal type and aggregate microenvironment govern the response sequence of speciation transformation of different heavy metals to microplastics in soil.

Sci Total Environ 2021 Jan 25;752:141956. Epub 2020 Aug 25.

State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

Microplastics change the physical, chemical, and biological processes in soil, and these changes further affect the transformations of heavy metal speciation in soil. Whether this influence mechanism differs between heavy metals is unknown on the soil aggregates level. In this study, 5 months incubation experiments and soil fractionation were conducted to evaluate the effect of microplastic addition on the chemical speciation of seven heavy metals (Zn, Cu, Ni, Cd, Cr, As, and Pb) in the three soil aggregate fractions. The results show that 28% concentration of polyethylene microplastics with size 100 μm reduces and increases the heavy metal content in the bioavailable and organic-bound fractions, respectively, indicating that microplastics promote the transformation from bioavailable to organic-bound species. The transformation in the larger-sized aggregate fractions is more dramatic than that of smaller-sized aggregate fractions within the incubation period. This indicates that the extent of the response of the different heavy metals to microplastics is significantly different in the three aggregate-size fractions. Soil physicochemical factors affected different heavy metals in different pathways, and microplastics have different adsorption or complexation effects on different heavy metals. These processes result in heterogeneous responses of different heavy metals to microplastic addition. In addition, the microplastics have different extents of influence on the different chemical speciation of the heavy metals, having the greatest influence on the exchangeable and carbonate-bound of Cu and Zn, FeMn oxide-bound of As, and organic-bound of Cr, Ni, Cd, and Pb. This phenomenon is relatively consistent among the three aggregate-size fractions. Our findings provide more accurate management information for soil environmental quality management with different heavy metal pollution and different soil types.
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http://dx.doi.org/10.1016/j.scitotenv.2020.141956DOI Listing
January 2021

Tracing bacterial and fungal necromass dynamics of municipal sludge in landfill bioreactors using biomarker amino sugars.

Sci Total Environ 2020 Nov 24;741:140513. Epub 2020 Jun 24.

State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address:

The dynamics of microbial necromass of municipal solid waste over long-term landfill remain unknown. This study presents the first investigation on the dynamics of bacterial and fungal necromass of municipal sludge in non-aeration versus alternating aeration landfill bioreactors by using amino sugar biomarkers. Results showed that under non-aeration treatment, the decomposition rate of muramic acid derived from bacteria is higher than that of fungal-derived glucosamine. The relative change in glucosamine and muramic acid in the early period of landfills under the alternating aeration treatment is consistent with that under non-aeration treatment. However, with the increase in alternating aeration cycles, bacterial necromass muramic acid exerts a lower decomposition rate than fungal necromass glucosamine. Throughout the entire landfill period, galactosamine is the amino sugar with the slowest decomposition rate under non-aeration mode but the amino sugar with the fastest decomposition rate under alternating aeration mode. The present work fills the knowledge gap of microbial necromass dynamics of municipal solid waste in landfills.
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http://dx.doi.org/10.1016/j.scitotenv.2020.140513DOI Listing
November 2020

Dissolved Silicate Enhances the Oxidation of Chlorophenols by Permanganate: Important Role of Silicate-Stabilized MnO Colloids.

Environ Sci Technol 2020 08 10;54(16):10279-10288. Epub 2020 Aug 10.

School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, China.

Dissolved silicate is an important background constituent of natural waters, but there is little clarity regarding the effect of silicate on the oxidizing capability of permanganate (Mn(VII)) and on its efficiency for remediation applications. In the present study, we found that dissolved silicate, metasilicate or disilicate (DS), could significantly promote the oxidation of 2,4-dichlorophenol (2,4-DCP) by Mn(VII), and the extent of the promoting effect was even more evident than that of pyrophosphate (PP). The experiments showed that, unlike PP, DS was not capable of coordinating with Mn(III) ions, and the promoting effect of DS was not due to the oxidizing capability of complexed Mn(III). Instead, DS ions, as a weak base, could combine with the hydroxyl groups of MnO via hydrogen bonding to limit the growth of colloidal MnO particles. The DS-stabilized colloidal MnO particles, with hydrodynamic diameters less than 100 nm, could act as catalysts to enhance the oxidation of 2,4-DCP by Mn(VII). The best promoting effect of DS on the performance of Mn(VII) oxidant was achieved at the initial solution pH of 7, and the coexisting bicarbonate ions further improved the oxidation of 2,4-DCP in the Mn(VII)/DS system. Sand column experiments showed that the combined use of Mn(VII) and DS additive could mitigate the problem of permeability reduction of sand associated with the retention of MnO particles. This study not only deepens our understanding on the role of dissolved silicate in a Mn(VII) oxidation process but also provides an effective and green method to enhance the oxidizing capacity of Mn(VII)-based treatment systems.
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http://dx.doi.org/10.1021/acs.est.0c00826DOI Listing
August 2020

A comparative study on the treatment of 2,4-dinitrotoluene contaminated groundwater in the combined system: efficiencies, intermediates and mechanisms.

Sci Total Environ 2020 Sep 4;735:139161. Epub 2020 May 4.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China. Electronic address:

In this study, scrap irons (SI)/granular activated carbons (GAC) micro-electrolysis treatment and persulfate-releasing materials (PRM) treatment were employed to construct the combination reduction and oxidation system to treat 2,4-dinitrotoluene (2,4-DNT) contaminated groundwater. The 2,4-DNT treatment efficiencies in the PRM pre-treatment before SI/GAC micro-electrolysis treatment (FM-1 = PRM + SI/GAC) and SI/GAC micro-electrolysis pre-treatment before the PRM treatment (FM-3 = SI/GAC + PRM) were investigated in two separated columns. As control groups, the separated SI and GAC instead of the SI/GAC mixture were used in another two separated columns (FM-2 = PRM + SI + GAC; FM-4 = SI + GAC + PRM). The highest treatment efficiencies of 2,4-DNT in the FM-1 and FM-3 systems reached 79% and 93% during 5 PV, respectively. We found that the filling position of SI, GAC and PRM significantly affected the variations of pH, oxidation-reduction potential, Fe and SO concentrations in the combined systems. These results indicated that the SI/GAC micro-electrolysis pre-treatment of 2,4-DNT before the PRM treatment (FM-3) is more beneficial. The fifteen main intermediates in the combined system were identified by the detection of liquid chromatograph mass spectrometer. Furthermore, the possible treatment pathways of 2.4-DNT were proposed on the basis of identified intermediates. The treatment mechanisms in the FM-1 and FM-3 systems were proposed with the reduction mechanism in the SI/GAC micro-electrolysis system and the oxidation mechanism in the PRM treatment. Therefore, the combination of the reduction pre-treatment with the SI/GAC micro-electrolysis system and the oxidation post-treatment with persulfate can effectively treat the nitroaromatic compounds contaminated groundwater.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139161DOI Listing
September 2020

Biogas slurry as an activator for the remediation of petroleum contaminated soils through composting mediated by humic acid.

Sci Total Environ 2020 Aug 1;730:139117. Epub 2020 May 1.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, China; The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, China. Electronic address:

Soil pollution caused by petroleum hydrocarbons is a widespread environmental problem. Composting is one of the cost-effective solutions for petroleum hydrocarbons removal but limited by low efficiency of bioremediation, leading to high phytotoxicity. Given that biogas slurry as nutrients can alter the microbial activity, the aim of this study was to investigate the role of biogas slurry on the remediation of petroleum contaminated soils in composting. Herein, we added biogas slurry into the composting of hydrocarbon contaminated soil to investigate its effect on the biodegradation of petroleum hydrocarbons, humic acid (HA) transformation and the safety of product. The results showed that biogas slurry addition improved the degradation of organic matter and total petroleum hydrocarbons (TPH) (especially C > 16), but also increased 18.0% of germination index and the humification degree of HA. The estrone from biogas slurry was removed during composting and did not affect the phytotoxicity level of compost. Redundancy analysis and structural equation modeling indicated that TPH degradation was significantly related to the humification of HA components and total nitrogen from biogas slurry, which contributed to composting safety. Therefore, biogas slurry could be a possible activator for the remediation of petroleum contaminated soils through composting mediated by HA transformation, which is beneficial to obtain the composts with a lower phytotoxicity and higher maturity for soil application.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139117DOI Listing
August 2020

Insights into the removal efficiencies of aged polycyclic aromatic hydrocarbons in humic acids of different soil aggregate fractions by various oxidants.

Environ Pollut 2020 Sep 27;264:114678. Epub 2020 Apr 27.

State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address:

Chemically oxidative removal of polycyclic aromatic hydrocarbons (PAHs) in soil is related to their occurrence state. Whether the heterogeneity of natural organic matter has an effect on the occurrence of PAHs in soil and, if there is an effect, on the oxidative removal efficiency of PAHs remains unknown. In this study, the removal efficiencies of 16 priority PAHs aged in humic acids (HAs) of different soil aggregate fractions by various oxidants were investigated by combining soil fractionation and microreaction experiments. Results showed that the accumulations of PAHs in particulate HA (P-HA) and microaggregate occluded HA (MO-HA) mainly occurred in the early period of the aging time frame. In contrast, PAH accumulation in non-aggregated silt and clay associated HA (NASCA-HA) was relatively slow and tended to saturate in the late period of the aging time frame. The cumulative contents of PAHs throughout the entire aging period in MO-HA and NASCA-HA were significantly greater than that in P-HA. The aged PAHs in P-HA and NASCA-HA exhibited the highest and lowest removal efficiencies, respectively. This ranking was mainly governed by the molecular size and polarity of HAs. Sodium persulfate and potassium permanganate had the highest removal efficiencies in total PAHs in HAs, with average efficiencies of 85.8% and 79.1%, respectively, in P-HA. Hydrogen peroxide had the lowest degradation efficiency in PAHs. In particular, the degradation efficiency of total PAHs in NASCA-HA was lowered to 31.0%. PAH congeners in HAs showed a large difference in oxidative removal efficiency. Low-ring PAH was more easily degraded than medium- and high-ring PAHs, and in most treatments, fluoranthene and pyrene in the medium ring and benzo[a]pyrene in the high ring demonstrated higher efficiencies than other PAHs with the same number of rings. Our findings are useful in promoting the accurate and green remediation of PAH-contaminated soils.
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http://dx.doi.org/10.1016/j.envpol.2020.114678DOI Listing
September 2020

Decrease in bioavailability of soil heavy metals caused by the presence of microplastics varies across aggregate levels.

J Hazard Mater 2020 08 13;395:122690. Epub 2020 Apr 13.

State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

Microplastics can alter the physicochemical and biogeochemical processes in soil, but whether these alterations have further the effects on the transformation of soil heavy metal speciation, and if so, whether these effects vary across soil aggregate levels remain unknown. Herein, long-term soil culture experiments and soil fractionation are combined to investigate the effects of microplastics on chemical speciation of Cu, Cr, and Ni with different particle-size soil aggregates. Results show that microplastics in soil decrease the exchangeable, carbonate-bound, and Fe-Mn oxide-bound fractions of metals but increase their organic-bound fractions via direct adsorption and indirect effects on the soil microenvironment conditions. The findings suggest that microplastics can promote the transformation of heavy metal speciation from bioavailable to organic bound. Such promotion exerts notable differences across soil aggregate levels. The transformation of soil heavy metal speciation is greater in larger aggregates than in smaller aggregates in the early incubation period with microplastics but shows the opposite trend in the later incubation period. Therefore, this process is more sensitive to long-term microplastic pollution in smaller aggregates than in larger aggregates, most likely owing to the lag in the influence of microplastics on metal speciation transformation in the smaller aggregates.
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http://dx.doi.org/10.1016/j.jhazmat.2020.122690DOI Listing
August 2020

A study of layered-unlayered extraction of benzene in soil by SVE.

Environ Pollut 2020 Aug 20;263(Pt B):114219. Epub 2020 Mar 20.

State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

With the aim to improve the pollution removal efficiency, a layered extraction simulation device for the removal of benzene-contaminated soil via soil vapor extraction was constructed. The removal of benzene from soils by both layered extraction and unlayered extraction was explored based on the factors of extraction flow, extraction time, initial contaminant content, initial soil moisture content, and extraction method. Under the same conditions, layered extraction improved the repair efficiency, shortened the repair time, and decreased the cost of repair. Different factors exerted different influences on the extraction effect, but overall, compared with unlayered extraction, the removal rate of layered extraction can be increased by 2-20%. In particular, when the content of benzene was high, layered and intermittent extraction could remove more than 90% of benzene from the soil. When layered extraction was adopted, the pressure loss in the lower part of the soil layer was small and the air flow into the soil was large, which can promote the volatilization of benzene and thus improve its removal rate.
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http://dx.doi.org/10.1016/j.envpol.2020.114219DOI Listing
August 2020

Accumulation characteristics and biological response of ginger to sulfamethoxazole and ofloxacin.

Environ Pollut 2020 Jul 5;262:114203. Epub 2020 Mar 5.

State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.

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 SMZ, 1 mg L OFL and 1 mg L (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, the contents of HO, O 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, the SMZ concentrations in rhizomes, roots, and leaves were 0.23, 0.15, and 0.05 mg kg, 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.
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http://dx.doi.org/10.1016/j.envpol.2020.114203DOI Listing
July 2020

Groundwater nitrate pollution risk assessment of the groundwater source field based on the integrated numerical simulations in the unsaturated zone and saturated aquifer.

Environ Int 2020 04 18;137:105532. Epub 2020 Feb 18.

State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address:

Groundwater pollution risk assessment in the groundwater source field (GSF) is crucial to ensure groundwater quality safety. A systematic method of assessing groundwater pollution in the GSF was established by combining the numerical models of groundwater flow and solute transport in the vadose zone and aquifer. It is featured by revealing the paramount fate of contaminant from the surface to receptor "well (wells)" via the pathway of vadose zone and aquifers. The method was verified in the phreatic and semi-confined aquifers of a vital GSF, Beijing-Tianjin-Hebei region (BTHR) in China. Nitrate was selected as the model pollutant. The results indicated that the groundwater pollution risk of the phreatic aquifer was dominated by the mediate level (45.27%), and that the second semi-confined aquifer was mainly ranked as relatively low (30.29%) and mediate (38.17%) levels. The groundwater pollution risk maps of the two aquifers were similar. The high and relatively high risk areas were affected by the high intensities of groundwater pollution sources (GPSIs) or short distances from the pollution sources to the pumping well. The low and relatively low risk areas were controlled by low GPSIs and adequate attenuation and denitrification of nitrate in the aquifer. The groundwater pollution risk in the semi-confined aquifer was lower than that in the phreatic aquifer. The groundwater pollution risk mapping provides a valuable scientific reference for the groundwater pollution prevention and control with the focus on the "pollution source" and "groundwater source field". The proposed method can be further applied to the protections of the GSFs in the BTHR.
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http://dx.doi.org/10.1016/j.envint.2020.105532DOI Listing
April 2020
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