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Leite LDS, dos Santos DV, Paschoalato CFPR, Bond T, Daniel LA. Disinfection By-Products Formation from Chlor( am)ination of Algal Organic Matter of Chlorella sorokiniana. TOXICS 2023; 11:690. [PMID: 37624194 PMCID: PMC10459932 DOI: 10.3390/toxics11080690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/06/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023]
Abstract
Eutrophication in water reservoirs releases algal organic matter (AOM), which is an important precursor of disinfection by-products (DBPs) formed during water treatment. Chlorella sorokiniana is a microalgae which flourishes under conditions of high light intensity and temperature, thus its prevalence in algal blooms is expected to increase with climate change. However, Chlorella sorokiniana AOM has not been previously investigated as a DBP precursor. In this context, this study evaluated the effect of AOM concentration, humic acid (HA), and pH on DBP formation from chlor(am)ination of AOM Chlorella sorokiniana. DBP yields determined by linear regression for trichloromethane (TCM) and chloral hydrate (CH) were 57.9 and 46.0 µg·mg DOC-1 in chlorination, while the TCM, CH, dichloroacetonitrile (DCAN), 1,1,1-trichloropropanone (1,1,1-TCP), and chloropicrin (CPN) concentrations were 33.6, 29.8, 16.7, 2.1, and 1.2 µg·mg DOC-1 in chloramination. Chloramination reduced the formation of TCM and CH but increased CPN, DCAN, and 1,1,1-TCP yields. AOM Chlorella sorokiniana showed a higher DBP formation than 9 of 11 algae species previously investigated in the literature. At basic pH, the concentration of TCM increased while the concentration of other DBP classes decreased. Bromide was effectively incorporated into the AOM structure and high values of bromine incorporation factor were found for THM (1.81-1.89) and HAN (1.32) at 1.5 mg Br·L-1. Empirical models predicted successfully the formation of THM and HAN (R2 > 0.86). The bromide concentration had more impact in the model on the DBP formation than AOM and HA. These results provide the first insights into the DBP formation from AOM chlor(am)ination of Chlorella sorokiniana.
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Affiliation(s)
- Luan de Souza Leite
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos 13566-59, São Paulo, Brazil
- School of Sustainability and Civil Engineering, University of Surrey, Guildford GU2 7XH, UK
| | | | | | - Tom Bond
- School of Sustainability and Civil Engineering, University of Surrey, Guildford GU2 7XH, UK
| | - Luiz Antonio Daniel
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos 13566-59, São Paulo, Brazil
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Ma L, Peng F, Dong Q, Li H, Yang Z. Identification of the key biochemical component contributing to disinfection byproducts in chlorinating algogenic organic matter. CHEMOSPHERE 2022; 296:133998. [PMID: 35181429 DOI: 10.1016/j.chemosphere.2022.133998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 02/12/2022] [Accepted: 02/13/2022] [Indexed: 06/14/2023]
Abstract
Disinfection byproducts (DBPs) remains an ongoing issue because of their widespread occurrence and toxicity. Various organic substances in Algogenic organic matter (AOM) can produce DBPs in the chlorination process. To provide specific suggestions for the targeted removal of DBP precursors in AOM, the main biochemical components in AOM were qualitatively and quantitatively analyzed. An accurate model for predicting the DBP formation potentials (DBPFPs) of AOM was herein developed based on the dissolved organic carbon of the five main biochemical components in AOM and the DBPFPs of their corresponding surrogates. The contributions of each biochemical component to the three DBP species were evaluated, and the key components were identified. The results showed that lipids, proteins, carbohydrates, humic acid-like substances, and fulvic acid-like substances were the main biochemical components in AOM. Thereof, proteins (71.2 ± 2.1%) and carbohydrates (53.1 ± 2.1%) were the major contributor to the carbon content in intracellular organic matter and extracellular organic matter, respectively. The contribution results of biochemical components to the formation of DBPs showed that proteins were the key contributor to DBPs, suggesting that the targeted removal of proteins before the chlorination process would effectively reduce DBPs from AOM.
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Affiliation(s)
- Lingfei Ma
- Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Changsha, 410083, PR China
| | - Fangyuan Peng
- Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Changsha, 410083, PR China
| | - Qingqing Dong
- Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Changsha, 410083, PR China
| | - Haipu Li
- Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Changsha, 410083, PR China.
| | - Zhaoguang Yang
- Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Changsha, 410083, PR China.
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Liang H, Huang X, Wang H, Xu W, Shi B. The role of extracellular organic matter on the cyanobacteria ultrafiltration process. J Environ Sci (China) 2021; 110:12-20. [PMID: 34593183 DOI: 10.1016/j.jes.2021.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 05/09/2023]
Abstract
The membrane fouling caused by extracellular organic matter (EOM) and algal cells and organic matter removal of two typical cyanobacteria (M. aeruginosa and Pseudoanabaena sp.) during ultrafiltration (UF) process were studied in this work. The results showed that EOM had a broad molecular weight (Mw) distribution and the irreversible membrane fouling was basically caused by EOM. Moreover, humic acid and microbial metabolites were major components of EOM of two typical cyanobacteria. Since EOM could fill the voids of cake layers formed by the algal cells, EOM and algal cells played synergistic roles in membrane fouling. Fourier transform infrared spectroscopy analysis indicated that the CH2 and CH3 chemical bonds may play an important role in membrane fouling caused by EOM. Interestingly, the cake layer formed by the algal cells could trap the organic matter produced by algae and alleviate some irreversible membrane fouling. The results also showed that although the cake layer formed by the algal cells cause severe permeate flux decline, it could play a double interception role with UF membrane and increase organic matter removal efficiency. Therefore, when using UF to treat algae-laden water, the balance of membrane fouling and organic matter removal should be considered to meet the needs of practical applications.
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Affiliation(s)
- Huikai Liang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing 100085, China; School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China
| | - Xin Huang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing 100085, China.
| | - Han Wang
- School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China
| | - Weiying Xu
- School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Ma B, Qi J, Wang X, Ma M, Miao S, Li W, Liu R, Liu H, Qu J. Moderate KMnO 4-Fe(II) pre-oxidation for alleviating ultrafiltration membrane fouling by algae during drinking water treatment. WATER RESEARCH 2018; 142:96-104. [PMID: 29864651 DOI: 10.1016/j.watres.2018.05.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 06/08/2023]
Abstract
Although ultrafiltration (UF) membranes are highly beneficial for removing algae, the removal process causes serious UF membrane fouling. To avoid the unfavorable effects of algal cells that have been damaged by oxidants, our previous study reported a novel, moderate pre-oxidation method (KMnO4-Fe(II) process) that aimed to achieve a balance between the release of intracellular organic matter and enhanced algae removal. This study further investigated the performance of a UF membrane with KMnO4-Fe(II) pretreatment in the presence of algae-laden reservoir water after a long running time. We found that algae could be completely removed, membrane fouling was significantly alleviated, and the overall performance was much better than that of Fe(III) coagulation alone. The transmembrane pressure (TMP) during Fe(III) coagulation increased to 42.8 kPa, however, that of the KMnO4-Fe(II) process only increased to 25.1 kPa for after running for 90 d. The slower transmembrane pressure was attributed to the larger floc size, higher surface activity, and inactivation of algae. Although there was little effect on microorganism development, lower microorganism abundance (20.7%) was observed during the KMnO4-Fe(II) process than during coagulation alone (44.9%) due to the release of extracellular polymeric substances. We also found that the floc cake layer was easily removed by washing, and many of the original membrane pores were clearly observed. Further analysis demonstrated that the effluent quality was excellent, especially its turbidity, chromaticity, and Mn and Fe concentrations. Based on the outstanding UF membrane performance, it may be concluded that the KMnO4-Fe(II) process exhibits considerable potential for application in the treatment of algae-laden water.
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Affiliation(s)
- Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jing Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xing Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Ma
- Technology Institute of Beijing Waterworks Group Co., Ltd., Beijing 100012, China; Beijing Engineering Research Center for Drinking Water Quality, Beijing 100012, China
| | - Shiyu Miao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjiang Li
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ruiping Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Huijuan Liu
- University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Lodhi A, Hashmi I, Nasir H, Khan R. Effect of trihalomethanes (chloroform and bromoform) on human haematological count. JOURNAL OF WATER AND HEALTH 2017; 15:367-373. [PMID: 28598341 DOI: 10.2166/wh.2017.207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
With the increasing concerns about the harmful effects of disinfection products, the process of chlorination is becoming questionable. Bromoform and chloroform are among the most frequently occurring disinfection by-products. Haematological parameters are an important indicator of human well-being which is why the prime objective of the current study was to conduct a dose-response assessment to investigate the effects of trihalomethanes on human haematological count. Blood samples of healthy subjects were exposed to different concentrations (10, 30 and 50 μg/mL) of chloroform and bromoform in vitro to analyse how these compounds affected the haematological count with increasing dose concentrations. Headspace gas chromatography analysis was also conducted on samples to assess the difference between measured and spiked values of doses. The results indicated that the damage caused by bromoform was statistically more significant as compared to chloroform. Haemoglobin (HGB) and mean corpuscular haemoglobin concentration levels lowered as they were significantly affected (p < 0.05) by bromoform at all administered doses. It also significantly damaged platelet level at doses of 30 (p < 0.05) and 50 μg/mL (p < 0.01). Conversely, the damage caused by chloroform was statistically less significant (p > 0.05).
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Affiliation(s)
- Asna Lodhi
- Institute of Environmental Sciences and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad, Pakistan E-mail:
| | - Imran Hashmi
- Institute of Environmental Sciences and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad, Pakistan E-mail:
| | - Habib Nasir
- School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad, Pakistan
| | - Romana Khan
- Institute of Environmental Sciences and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad, Pakistan E-mail:
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Tomlinson A, Drikas M, Brookes JD. The role of phytoplankton as pre-cursors for disinfection by-product formation upon chlorination. WATER RESEARCH 2016; 102:229-240. [PMID: 27348195 DOI: 10.1016/j.watres.2016.06.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 06/06/2023]
Abstract
Water quality remains one of the greatest concerns with regards to human health. Advances in science and technology have resulted in highly efficient water treatment plants, significantly reducing diseases related to waterborne pathogenic microorganisms. While disinfection is critical to mitigate pathogen risk to humans, the reactions between the disinfectant and dissolved organic compounds can lead to the formation of chemical contaminants called disinfection by-products (DBPs). DBPs have been related to numerous health issues including birth defects and cancer. The formation of disinfection by-products occurs due to the reaction of oxidants and natural organic matter. DBP precursors are derived from anthropogenic sources including pharmaceuticals and chemical waste, the breakdown of vegetation from external catchment sources (allochthonous) and internally derived sources including phytoplankton (autochthonous). Current literature focuses on the contribution of allochthonous sources towards the formation of DBPs, however, the recalcitrant nature of hydrophilic phytoplankton derived organic matter indicates that autochthonous derived organic carbon can significantly contribute to total DBP concentrations. The contribution of phytoplankton to the formation of DBPs is also influenced by cellular exudation rates, chemical composition, environmental conditions and the physical and chemical conditions of the solution upon disinfection. Formation of DBPs is further influenced by the presence of cyanobacteria phyla due to their notoriety for forming dense blooms. Management of DBP formation can potentially be improved by reducing cyanobacteria as well as DBP precursors derived from other phytoplankton.
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Affiliation(s)
- Adam Tomlinson
- Water Research Centre, Environment Institute, School of Biological Sciences, The University of Adelaide 5005, Australia.
| | - Mary Drikas
- Australian Water Quality Centre, South Australian Water Corporation, Victoria Square, Adelaide 5000, Australia
| | - Justin D Brookes
- Water Research Centre, Environment Institute, School of Biological Sciences, The University of Adelaide 5005, Australia
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Qi J, Lan H, Miao S, Xu Q, Liu R, Liu H, Qu J. KMnO4-Fe(II) pretreatment to enhance Microcystis aeruginosa removal by aluminum coagulation: Does it work after long distance transportation? WATER RESEARCH 2016; 88:127-134. [PMID: 26479785 DOI: 10.1016/j.watres.2015.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/27/2015] [Accepted: 10/02/2015] [Indexed: 06/05/2023]
Abstract
KMnO4-Fe(II) pretreatment was proposed to enhance Microcystis aeruginosa (M. aeruginosa) removal by aluminum (Al) coagulation in drinking water treatment plants (DWTPs) in our previous study. This study aims to optimize this process and evaluate the feasibility of using the process at water sources, which are usually far away from DWTPs. The optimum molar ratio of KMnO4 to Fe(II) [Formula: see text] is observed to be 1:3 with respect to algae removal and residual manganese (Mn) control. As indicated from flow cytometer analysis, KMnO4 at <20 μM promisingly maintains cell integrity, with damaged cell ratios of below 10%. KMnO4 at 30 and 60 μM damages M. aeruginosa cells more significantly and the damaged cell ratios increase to 21% and 34% after 480 min. The intracellular organic matter (IOM) release can be controlled by the subsequent introduction of Fe(II) to quench residual KMnO4. KMnO4-Fe(II) pretreatment at the KMnO4 dose of 10 μM dramatically enhances the algae removal by over 70% compared to that by Al coagulation, even if KMnO4 and Fe(II) are introduced 480 min prior to the addition of Al2(SO4)3. The Al doses can be reduced by more than half to achieve the same algae removal. Furthermore, the deposition of the tiny Fe-Mn precipitates formed rarely occurs, as indicated by a settleability evaluation prior to Al addition. The KMnO4-Fe(II) process can be sequentially dosed at intake points in water sources to achieve moderate inactivation of algae cells and to enhance algae removal in DWTPs thereafter.
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Affiliation(s)
- Jing Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Graduate School of Chinese Academy of Sciences, Beijing 100039, China
| | - Huachun Lan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Shiyu Miao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Qiang Xu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ruiping Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Huijuan Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Pu Y, Kong L, Huang X, Ding G, Gao N. Formation of THMs and HANs during bromination of Microcystis aeruginosa. J Environ Sci (China) 2013; 25:1795-1799. [PMID: 24520721 DOI: 10.1016/s1001-0742(12)60235-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Bromine-contained disinfectants and biocides are widely used in swimming pools, recreational waters and cooling towers. The objective of this study was to evaluate the formation of thrihalomethanes (THMs) and haloacetonitriles (HANs) and their cytotoxicity in algae solutions during free bromine disinfection. Disinfection by-products formation potential experiments were conducted using model solutions containing 7 mg/L (as total organic carbon) Microcystis aeruginosa cells. Effects of free bromine dosage, pH and ammonia were investigated. The results showed that brominated disinfection by-products were the major products when free bromine was applied. The total THMs formed during bromination was much as that formed during chlorination, whereas HANs were elevated by using bromination instead of chlorination. Dibromoacetonitrice (C2H2NBr2) and bromoform (CHBr3) were the only detected species during free bromine disinfection. The production of C2H2NBr2 and CHBr3 increased with disinfectant dosage but decreased with dosing ammonia. CHBr3 increased with the pH changing from 5 to 9. However, C2H2NBr2 achieved the highest production at neutral pH, which was due to a joint effect of variation in hydrolysis rate and free bromine reactivity. The hydrolysis of C2H2NBr2 was base-catalytic and nearly unaffected by disinfectant. Finally, estimation of cytotoxicity of the disinfected algae solutions showed that HANs formation was responsible for the majority of toxicity. Considering its highest toxicity among the measured disinfection by-products, the elevated C2H2NBr2 should be considered when using bromine-related algaecide.
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Affiliation(s)
- Yunzhu Pu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
| | - Lingzhao Kong
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
| | - Xin Huang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Guoji Ding
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Naiyun Gao
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200091, China
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Ma M, Liu R, Liu H, Qu J. Chlorination of Microcystis aeruginosa suspension: cell lysis, toxin release and degradation. JOURNAL OF HAZARDOUS MATERIALS 2012; 217-218:279-285. [PMID: 22483441 DOI: 10.1016/j.jhazmat.2012.03.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 02/15/2012] [Accepted: 03/10/2012] [Indexed: 05/31/2023]
Abstract
Although the release of intracellular toxins after chlorination has been reported, the relation between cell lysis and the release and degradation of toxins during chlorination has not been well illustrated. This study used Microcystis aeruginosa to investigate the release and degradation behaviors of toxins after its exposure to chlorine at different doses for prolonged contact time. Scanning electron microscopy (SEM) analysis indicates no considerable change in the morphology for most algae cells. However, the release of intracellular K(+) and intracellular organic matter (IOM) did occur, and the significant K(+) release of 63% was observed even at chlorine exposure as low as 0.8 mg/L min. The damage of cell membrane was faster than the release of intracellular MCLR at all chlorine doses. Extracellular MCLR accumulated as a result of the fact that intracellular MCLR released from damaged cells faster than it was degraded by chlorine, especially at low dose of chlorine (0.8 mg/L). A maximum level of extracellular toxin at a contact time of 60, 30 and 1 min was observed at chlorine doses of 1.2, 1.6 and 2.0mg/L, respectively. In addition, Cl(2) consumption (%), toxin release and degradation (%), and cells lysis (%) were well related.
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Affiliation(s)
- Min Ma
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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Physiologically Based Pharmacokinetic (PBPK) Modeling of Metabolic Pathways of Bromochloromethane in Rats. J Toxicol 2012; 2012:629781. [PMID: 22719758 PMCID: PMC3377357 DOI: 10.1155/2012/629781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/27/2012] [Accepted: 03/30/2012] [Indexed: 11/18/2022] Open
Abstract
Bromochloromethane (BCM) is a volatile compound and a by-product of disinfection of water by chlorination. Physiologically based pharmacokinetic (PBPK) models are used in risk assessment applications. An updated PBPK model for BCM is generated and applied to hypotheses testing calibrated using vapor uptake data. The two different metabolic hypotheses examined are (1) a two-pathway model using both CYP2E1 and glutathione transferase enzymes and (2) a two-binding site model where metabolism can occur on one enzyme, CYP2E1. Our computer simulations show that both hypotheses describe the experimental data in a similar manner. The two pathway results were comparable to previously reported values (Vmax = 3.8 mg/hour, Km = 0.35 mg/liter, and kGST = 4.7 /hour). The two binding site results were Vmax1 = 3.7 mg/hour, Km1 = 0.3 mg/hour, CL2 = 0.047 liter/hour. In addition, we explore the sensitivity of different parameters for each model using our obtained optimized values.
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