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Ge C, Huang M, Huang D, Dang F, Huang Y, Ahmad HA, Zhu C, Chen N, Wu S, Zhou D. Effect of metal cations on antimicrobial activity and compartmentalization of silver in Shewanella oneidensis MR-1 upon exposure to silver ions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156401. [PMID: 35654200 DOI: 10.1016/j.scitotenv.2022.156401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/28/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Silver is an antimicrobial agent that is used extensively in consumer products, such as fabrics and humidifiers. Silver ion (Ag+) uptake in bacteria represents a crucial phase of antimicrobial activity. However, the uptake mechanism of Ag+ in bacteria remains largely unknown. The genus Shewanella drives many geochemical processes of nutrients and pollutants in soils. In the present study, Ag+ uptake by Shewanella oneidensis MR-1 was first investigated in a laboratory in defined anaerobic, oligotrophic, and inorganic media with or without cations (potassium ions [K+], magnesium ions [Mg2+], and zinc ions [Zn2+]). Our results revealed variations in antimicrobial activity of Ag+ in the presence of Mg2+ and Zn2+. First, Mg2+ significantly decreased antimicrobial activity of Ag+ in S. oneidensis MR-1 by inhibiting cellular Ag+ uptake when compared with K+. The results were consistent with that of Co2+ (Mg2+ channel blocker) decreased Ag+ uptake by S. oneidensis MR-1. Moreover, Mg2+ promoted riboflavin secretion and facilitated the formation of metallic Ag nanoparticles on bacterial surfaces, which was beneficial for extracellular electron transfer and consequently reduced antibacterial activity of Ag+. Second, Zn2+ increased the antimicrobial activity of Ag+ in S. oneidensis MR-1, although the effect on Ag+ uptake was minimal. A synergistic interaction between Zn2+ and Ag+ led to an increase in dead cells and decreased ferrihydrite reduction capacity. The findings suggest that Mg2+ could reduce the environmental risk of Ag+ to soil bacteria, while Zn2+ should be of particular concern due to its synergistic antimicrobial effect on bacteria.
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Affiliation(s)
- Chenghao Ge
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Mingquan Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Danyu Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, PR China
| | - Yingnan Huang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Hafiz Adeel Ahmad
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China
| | - Changyin Zhu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Ning Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Song Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Dongmei Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
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2
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Huang Z, Zeng Z, Song Z, Chen A, Zeng G, Xiao R, He K, Yuan L, Li H, Chen G. Antimicrobial efficacy and mechanisms of silver nanoparticles against Phanerochaete chrysosporium in the presence of common electrolytes and humic acid. JOURNAL OF HAZARDOUS MATERIALS 2020; 383:121153. [PMID: 31518805 DOI: 10.1016/j.jhazmat.2019.121153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 09/02/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
In this study, influences of cations (Na+, K+, Ca2+, and Mg2+), anions (NO3-, Cl-, and SO42-), and humic acid (HA) on the antimicrobial efficacy of silver nanoparticles (AgNPs)/Ag+ against Phanerochaete chrysosporium were investigated by observing cell viability and total Ag uptake. K+ enhanced the antimicrobial toxicity of AgNPs on P. chrysosporium, while divalent cations decreased the toxicity considerably, with preference of Ca2+ over Mg2+. Impact caused by a combination of monovalent and divalent electrolytes was mainly controlled by divalent cations. Compared to AgNPs, however, Ag+ with the same total Ag content exhibited stronger antimicrobial efficacy towards P. chrysosporium, regardless of the type of electrolytes. Furthermore, HA addition induced greater microbial activity under AgNP stress, possibly originating from stronger affinity of AgNPs over Ag+ to organic matters. The obtained results suggested that antimicrobial efficacy of AgNPs was closely related to water chemistry: addition of divalent electrolytes and HA reduced the opportunities directly for AgNP contact and interaction with cells through formation of aggregates, complexes, and surface coatings, leading to significant toxicity reduction; however, in monovalent electrolytes, the dominating mode of action of AgNPs could be toxic effects of the released Ag+ on microorganisms due to nanoparticle dissolution.
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Affiliation(s)
- Zhenzhen Huang
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Zhuotong Zeng
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Zhongxian Song
- Faculty of Environmental and Municipal Engineering, Henan Key Laboratory of Water Pollution Control and Rehabilitation Technology, Henan University of Urban Construction, Pingdingshan 467036, China
| | - Anwei Chen
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China.
| | - Rong Xiao
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, China.
| | - Kai He
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Lei Yuan
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Hui Li
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Guiqiu Chen
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
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3
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Zheng X, Yang L, Shen Q, Zhou C. Evaluation of Zinc Oxide Nanoparticles-Induced Effects on Nitrogen and Phosphorus Removal from Real and Synthetic Municipal Wastewater. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00641] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Avenue, Tempe, Arizona 85287-5701, United States
| | - Lan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Qiuting Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Chen Zhou
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Avenue, Tempe, Arizona 85287-5701, United States
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4
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Liu X, Dumitrescu E, Kumar A, Austin D, Goia D, Wallace KN, Andreescu S. Differential lethal and sublethal effects in embryonic zebrafish exposed to different sizes of silver nanoparticles. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 248:627-634. [PMID: 30844699 DOI: 10.1016/j.envpol.2019.02.085] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 02/20/2019] [Accepted: 02/24/2019] [Indexed: 06/09/2023]
Abstract
Various parameters can influence the toxic response to silver nanoparticles (Ag NPs), including the size and surface properties, as well as the exposure environment and the biological site of action. Herein, we assess the intestinal toxicity of three different sizes (10, 40, and 100 nm) of Ag NPs in embryonic zebrafish, and describe the relationship between the properties and behavior of Ag NPs in the exposure medium, and induction of lethal and sublethal effects. We find that the composition of the medium and the size contribute to differential NPs agglomeration, release of Ag ions, and subsequent effects during exposure. The exposure medium causes dramatic reduction in silver dissolution due to the presence of salts and divalent cations, which limits the lethal potential of silver ions. Lethality is observed primarily for embryos exposed to medium sized Ag NPs (40 nm), but not to the supernatant originated from particles, which suggests that the exposure to particulate silver is the main cause of mortality. On the other hand, the exposure to 10 nm and 100 nm NPs, as well as Ag ions, only causes sublethal developmental defects in skeletal muscles and intestine, and induces a nitric oxide imbalance.
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Affiliation(s)
- Xiaobo Liu
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA
| | - Eduard Dumitrescu
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA
| | - Ajeet Kumar
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA
| | - Daniel Austin
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA
| | - Dan Goia
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA
| | - Kenneth N Wallace
- Department of Biology, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5805, USA
| | - Silvana Andreescu
- Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA.
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Wu S, Wu H, Button M, Konnerup D, Brix H. Impact of engineered nanoparticles on microbial transformations of carbon, nitrogen, and phosphorus in wastewater treatment processes - A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 660:1144-1154. [PMID: 30743910 DOI: 10.1016/j.scitotenv.2019.01.106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Concern regarding the potential negative impacts of released engineered nanoparticles (ENPs) on pollutant removal performance of wastewater treatment systems has received booming attention in recent years. However, the conclusions drawn from different studies often lead to fragmented overall knowledge, some of which are even contradictory. This scenario shows the necessity for a comprehensive review of the interactions of ENPs in wastewater treatment systems, particularly on the impacts of ENPs on microbial processes of carbon (C), nitrogen (N), and phosphorus (P) removal in water treatment systems. This review introduced the impact of 6 often reported ENPs in 5 types of treatment systems. We found that exposure to most of the investigated ENPs at low concentrations doesn't adversely influence the growth of the heterotrophic microbes, which are responsible for organic matter removal. The impacts of ENPs on various microbial nitrogen transformation processes have been investigated. Dosing of ENPs often causes acute microbial nitrogen removal inhibition at various concentrations, but does not influence long-term operation due to microbial adaption. No significant negative effects on biological phosphorus removal in different wastewater treatment processes have been reported after both short-term and long-term exposure (except copper nanoparticles). Environmentally relevant concentrations of ENPs have been reported to enhance the photosynthetic capacity of wetland plants, whereas chronic inhibition to photosynthesis was found in exposure to high concentrations of ENPs. Inhibition effects are often overestimated in pure cultivated toxicity test assays compared to testing with artificially prepared wastewater containing various ingredients or with real wastewater. Potential ligands in real wastewater can bind with ENPs and lower their dissolution. Some challenges exist regarding detection and quantification techniques of ENPs at environmental concentrations, modeling of engineered nanomaterial release on a worldwide scale, and inhibitory mechanisms to microbial transformations.
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Affiliation(s)
- Shubiao Wu
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus 8000C, Denmark; Department of Bioscience, Aarhus University, Aarhus 8000C, Denmark.
| | - Haiming Wu
- College of Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Mark Button
- Department of Earth and Environmental Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Dennis Konnerup
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus 8000C, Denmark; Department of Bioscience, Aarhus University, Aarhus 8000C, Denmark
| | - Hans Brix
- Department of Bioscience, Aarhus University, Aarhus 8000C, Denmark
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6
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Barker LK, Giska JR, Radniecki TS, Semprini L. Effects of short- and long-term exposure of silver nanoparticles and silver ions to Nitrosomonas europaea biofilms and planktonic cells. CHEMOSPHERE 2018; 206:606-614. [PMID: 29778938 DOI: 10.1016/j.chemosphere.2018.05.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 04/27/2018] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
The increasing use of silver nanoparticles (AgNPs) in consumer products, and their resulting influx into wastewater, may pose a threat to biological nutrient removal in wastewater treatment plants. Planktonic ammonia-oxidizing bacteria (AOB), which convert ammonia to nitrite in the first step of nitrification, are highly sensitive to AgNPs and their released silver ions (Ag+), but the sensitivity of AOB biofilms to AgNPs and Ag+ is less clear. This study demonstrated that biofilms of Nitrosomonas europaea, a model AOB, were more resistant to both short-term and long-term exposure to AgNP and Ag+ than planktonic cells. The increased resistance of N. europaea biofilms was attributed primarily to the increased biomass and slower growth rates present in the biofilm. Similar inhibition mechanisms were observed for AgNPs and Ag+ in both planktonic cells and biofilms with enzymatic inhibition observed at lower concentrations and cell lysis observed at higher concentrations. Long-term continuous exposure to AgNPs lowered the inhibitory concentration by 1-2 orders of magnitude below that required by short-term exposures. Although the total AgNP load was similar between the short and long-term exposure scenarios, the long-term exposure resulted in an order of magnitude more silver being associated in the biofilms and is the primary reason for the increased sensitivity observed. This suggests that short-term batch toxicity assays may greatly underestimate the sensitivity of biofilm treatment systems to long-term exposures of low concentrations of AgNPs and Ag+.
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Affiliation(s)
- L K Barker
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - J R Giska
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - T S Radniecki
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
| | - L Semprini
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
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7
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Sheng Z, Van Nostrand JD, Zhou J, Liu Y. Contradictory effects of silver nanoparticles on activated sludge wastewater treatment. JOURNAL OF HAZARDOUS MATERIALS 2018; 341:448-456. [PMID: 28830010 DOI: 10.1016/j.jhazmat.2017.07.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/22/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
Increased amount of nano-silver will be released into domestic and industrial waste streams due to its extensive application. However, great controversy still exists on the effects of silver nanoparticle (Ag-NP) on biological wastewater treatment processes and a toxicology model has not been built yet. Four sequencing batch reactors with activated sludge has been run for over three months with different silver species at a concentration of 1mg Ag/L in influent. Both freshly prepared Ag-NPs and aged Ag-NPs were tested with released silver ion as control. Results in this study showed that Ag-NPs, especially freshly prepared Ag-NPs, can help to maintain or even increase the diversity of microbial community in activated sludge and the biomass concentration even under long-term treatment. It indicates that the hormesis model need to be considered for the toxicology of Ag-NPs.
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Affiliation(s)
- Zhiya Sheng
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2W2, Canada
| | - Joy D Van Nostrand
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2W2, Canada.
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8
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Sheng Z, Liu Y. Potential impacts of silver nanoparticles on bacteria in the aquatic environment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 191:290-296. [PMID: 28129561 DOI: 10.1016/j.jenvman.2017.01.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 12/12/2016] [Accepted: 01/14/2017] [Indexed: 06/06/2023]
Abstract
It is inevitable that nano-silver will be released into the environment. Therefore, there is an urgent need to better understand the effects of silver nanoparticles (Ag-NPs) on microbes in natural and engineered environments. The most remarkable gap in our knowledge on this lies on the low Ag-NPs dose side. This review summarized studies on the effects of Ag-NPs on bacteria from simple to complicated aquatic systems. A hormetic model with a narrow stimulatory zone has been proposed based on both experimental phenomenon and the potential mechanisms of the observed effects. Spectrum of the stimulating zone depends on Ag-NP properties, bacterial types and environmental conditions tested. This may become a concern in terms of Ag-NP disposal, and further research is required to build a sophisticated toxicity model for Ag-NPs.
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Affiliation(s)
- Zhiya Sheng
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2W2, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2W2, Canada.
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9
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Walden C, Zhang W. Biofilms Versus Activated Sludge: Considerations in Metal and Metal Oxide Nanoparticle Removal from Wastewater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8417-8431. [PMID: 27437755 DOI: 10.1021/acs.est.6b01282] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The increasing application of metal and metal oxide nanoparticles [Me(O)NPs] in consumer products has led to a growth in concentration of these nanoparticles in wastewater as emerging contaminants. This may pose a threat to ecological communities (e.g., biological nutrient removal units) within treatment plants and those subject to wastewater effluents. Here, the toxicity, fate, and process implications of Me(O)NPs within wastewater treatment, specifically during activated sludge processing and biofilm systems are reviewed and compared. Research showed activated sludge achieves high removal rate of Me(O)NPs by the formation of aggregates through adsorption. However, recent literature reveals evidence that inhibition is likely for nutrient removal capabilities such as nitrification. Biofilm systems were much less studied, but show potential to resist Me(O)NP inhibition and achieve removal through possible retention by sorption. Implicating factors during bacteria-Me(O)NP interactions such as aggregation, surface functionalization, and the presence of organics are summarized. At current modeled levels, neither activated sludge nor biofilm systems can achieve complete removal of Me(O)NPs, thus allowing for long-term environmental exposure of diverse biological communities to Me(O)NPs in streams receiving wastewater effluents. Future research directions are identified throughout in order to minimize the impact of these nanoparticles released.
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Affiliation(s)
- Connie Walden
- Graduate Research Assistant, Department of Civil Engineering, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Wen Zhang
- Assistant Professor, Department of Civil Engineering, University of Arkansas , Fayetteville, Arkansas 72701, United States
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10
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Du X, Wang X, You S, Wang Q, Gong X. A case study of aggregation behaviors of titanium dioxide nanoparticles in the presence of dodecylbenzene sulfonate in natural water. J Environ Sci (China) 2015; 36:84-92. [PMID: 26456610 DOI: 10.1016/j.jes.2015.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 06/05/2023]
Abstract
The present work aims to ascertain the mechanisms of surfactant (dodecylbenzene sulfonate; DBS) effects on the aggregation behaviors of TiO2 nanoparticles (TiO2-NPs) in natural water samples. Aggregation experiments were conducted at a TiO2-NPs concentration of 10mg/L in deionized water and in natural water samples via dynamic light scattering and Zeta potential determination. Average attachment efficiency was calculated to compare the aggregation behaviors of nanoparticles in the two aqueous media. Results showed that the effects of DBS on aggregation could be interpreted by both Derjaguin-Landau-Verwey-Overbeek (DLVO) and non-DLVO mechanisms. In natural water samples, aggregation did not occur rapidly and was able to develop slowly under all conditions, and the roles of DBS were obvious at high DBS concentration owing to the impacts of inherent components of natural water samples, such as colloids and natural organic compounds. Future aggregation studies should concentrate on multi-factor, multi-colloidal and dynamic aspects under similar environmental conditions.
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Affiliation(s)
- Xin Du
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Xiuheng Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Shijie You
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qiuru Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xiaobo Gong
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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11
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Loo SL, Krantz WB, Hu X, Fane AG, Lim TT. Impact of solution chemistry on the properties and bactericidal activity of silver nanoparticles decorated on superabsorbent cryogels. J Colloid Interface Sci 2015; 461:104-113. [PMID: 26397916 DOI: 10.1016/j.jcis.2015.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 11/17/2022]
Abstract
This study investigated the effects of dissolved organic matter (DOM) and various electrolytes commonly found in environmental aqueous matrices on the physicochemical properties and bactericidal efficacy of silver nanoparticles (AgNPs), which are immobilized on cryogels (or PSA/AgNP cryogel). The AgNPs in the PSA/AgNP cryogel that were exposed to different media underwent morphological transformation in terms of particle size and structure. In addition, the presence of DOM and electrolytes increased the release of dissolved Ag. The biological uptake of Ag species (determined as the total Ag in exposed cells) increased in the presence of DOM, but decreased in the presence of electrolytes. The presence of electrolytes did not result in any significant reduction in the bactericidal activity. Although an initial increase of the DOM to 2.5 mg-C L(-1) attenuated the bactericidal efficacy of the immobilized AgNPs, an increase in the DOM concentration beyond 5 mg-C L(-1) enhanced the bactericidal efficacy. This study found that the bactericidal activity of the immobilized AgNPs is less sensitive to the solution chemistry relative to the free AgNPs. This suggests that immobilizing the AgNPs in a supporting material is a good strategy to preserve their efficacy for disinfection in various aqueous matrices.
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Affiliation(s)
- Siew-Leng Loo
- Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #05-05, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - William B Krantz
- School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, 50 Nanyang Avenue, Singapore 639798, Singapore; Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309-0424, USA
| | - Xiao Hu
- School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, 50 Nanyang Avenue, Singapore 639798, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Anthony G Fane
- Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #05-05, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, 50 Nanyang Avenue, Singapore 639798, Singapore.
| | - Teik-Thye Lim
- Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #05-05, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, 50 Nanyang Avenue, Singapore 639798, Singapore.
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12
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Abstract
Silver nanoparticles (Ag-NPs) have strong antibacterial properties, which may adversely affect biological wastewater treatment processes. To determine the overall effect, intact biofilm samples were collected from the rotating biological contactor at the local wastewater treatment plant and treated with 200 mg Ag/L Ag-NPs for 24 h. The biofilm uptake of Ag-NPs was monitored with transmission electron microscopy. Forty-five minutes after Ag-NP application, Ag-NPs were seen in the biofilm extracellular polymeric substances (EPS). After 24 h, Ag-NPs had entered certain microbial cells, while other cells contained no observable Ag-NPs. Some cells were dying after the uptake of Ag-NPs. However, there was no significant reduction in cultivable bacteria in the biofilms, based on heterotrophic plate counts (HPC). While this may indicate that wastewater biofilms are highly resistant to Ag-NPs, the HPC represents only a small portion of the total microbial population. To further investigate the effects of Ag-NPs, a GeoChip microarray was used to directly detect changes in the functional gene structure of the microbial community in the biofilm. A clear decrease (34.6% decreases in gene number) in gene diversity was evident in the GeoChip analysis. However, the complete loss of any specific gene was rare. Most gene families present in both treated and untreated biofilms. However, this doesn’t necessarily mean that there was no change in these families. Signal intensity decreased in certain variants in each family while other variants increased to compensate the effects of Ag-NPs. The results indicate that Ag-NP treatment decreased microbial community diversity but did not significantly affect the microbial community function. This provides direct evidence for the functional redundancy of microbial community in engineered ecosystems such as wastewater biofilms.
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Affiliation(s)
- Zhiya Sheng
- Department of Civil and Environmental Engineering, University of Alberta Edmonton, AB, Canada
| | - Joy D Van Nostrand
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, The University of Oklahoma Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, The University of Oklahoma Norman, OK, USA
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta Edmonton, AB, Canada
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13
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Westmeier D, Chen C, Stauber RH, Docter D. The bio-corona and its impact on nanomaterial toxicity. EUROPEAN JOURNAL OF NANOMEDICINE 2015. [DOI: 10.1515/ejnm-2015-0018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AbstractThe rapidly growing application of nano-sized materials and nano-scaled processes will result in increased exposure of humans and the environment. The small size of nanomaterials (NM) comparable with molecular building blocks of cells raises concerns that their toxic potential cannot be extrapolated from studies of larger particles due to their unique physico-chemical properties. These properties are also responsible that NM rapidly adsorb various (bio)molecules when introduced into complex physiological or natural environments. As the thus formed protein/biomolecule ‘corona’ seems to affect the NM’ in situ identity, an understanding of its toxicological relevance and the biophysical forces regulating corona formation is needed but not yet achieved. This review introduces our current concept of corona formation and evolution and present analytical methods for corona profiling. We discuss toxicity mechanisms potentially affected by the biomolecule corona, including NM cellular uptake and impact on components of the blood system. Further, we comment on pending knowledge gaps and challenges, which need to be resolved by the field. We conclude by presenting a tiered systems biology-driven approach recommended to mechanistically understand the coronas’ nanotoxicological relevance and predictive potential.
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