1
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Kozerski GE, Kim J, Durham JA, Townsend B. Batch equilibrium experiments and modeling reveal weak temperature dependence of cyclic volatile methylsiloxane sorption in soil/sediment organic carbon-water systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 942:173541. [PMID: 38802002 DOI: 10.1016/j.scitotenv.2024.173541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/16/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
The organic carbon normalized partition coefficient, KOC, describes the equilibrium distribution of a chemical between water and organic carbon in soil or sediment. It is a key parameter in evaluating chemical persistence, mass distribution, and transport using multimedia fate and transport models. Considerable uncertainty remains about the KOC values of cyclic volatile methylsiloxane (cVMS) compounds, and in particular the dependence of KOC on temperature. In this study, we used a batch equilibrium (BE) method to measure KOC values and their temperature dependence between ∼5 and 25 °C for octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) with soil and sediments. Approximate log KOC values at 25 °C were 4.5-5.0 for D4 and 5.5-6.1 for D5 with different sorbents, and decreased by 0.3 log units or less at 4-5 °C. Enthalpies of sorption, ΔHOC, obtained for the different sorbents ranged from +7.2 to +16 kJ mol-1, with average values of +7.9 and +13 kJ mol-1 for D4 and D5, respectively. These values differ in magnitude and direction from those reported elsewhere based on KOC values determined by a novel dynamic purge-and-trap (PnT) method, but are consistent with predictions based on their solvation properties. A new fugacity-based multimedia model incorporating sorption/desorption kinetics was developed and used to predict concentrations in the phases of BE and PnT systems during desorption of cVMS under different experimental and ideal conditions. Model simulations suggested that KOC values for cVMS compounds derived from the PnT systems could be influenced by sorption disequilibrium between water and solids controlled by desorption rates from the particle phase to water, and subsequent losses due to volatilization and degradation. This has the potential to result in overestimation of KOC values when fitting the experimental data of cVMS mass remaining in a PnT system over time, which could explain the observed differences between the methods.
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Affiliation(s)
- Gary E Kozerski
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI, USA.
| | - Jaeshin Kim
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI, USA
| | - Jeremy A Durham
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI, USA
| | - Brent Townsend
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI, USA
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2
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Cantu MA, Durham JA, McClymont EL, Vogel AH, Gobas FAPC. Low Dietary Uptake Efficiencies and Biotransformation Prevent Biomagnification of Octamethylcyclotetrasiloxane (D4) and Decamethylcyclopentasiloxane (D5) in Rainbow Trout. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10252-10261. [PMID: 38811014 PMCID: PMC11171459 DOI: 10.1021/acs.est.4c00457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/31/2024]
Abstract
With octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) being considered for evaluation under the UN Stockholm Convention on Persistent Organic Pollutants, which specifically acknowledges risks of biomagnification of persistent organic pollutants in traditional foods, a study into the mechanism of the biomagnification process of D4 and D5 in Rainbow trout was conducted by combining the absorption-distribution-metabolism-excretion for bioaccumulation (ADME-B) approach to determine intestinal and somatic biotransformation rates and radiochemical analyses to identify metabolite formation. High rates of intestinal biotransformation of D4 and D5 (i.e., 2.1 (0.70 SE) and 0.88 (0.67 SE) day-1, respectively) and metabolite formation [i.e., 52.0 (17 SD)% of D4 and 56.5% (8.2 SD)% of D5 were metabolized] were observed that caused low dietary uptake efficiencies of D4 and D5 in fish of 15.5 (2.9 SE)% and 21.0 (6.5 SE)% and biomagnification factors of 0.44 (0.08 SE) for D4 and 0.78 (0.24 SE) kg-lipid·kg-lipid-1 for D5. Bioaccumulation profiles indicated little effect of growth dilution on the bioaccumulation of D4 and D5 in fish and were substantially different from those of PCB153. The study highlights the importance of intestinal biotransformation in negating biomagnification of substances in organisms and explains differences between laboratory tests and field observations of bioaccumulation of D4 and D5.
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Affiliation(s)
- Mark A. Cantu
- School
of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jeremy A. Durham
- Toxicology
and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - E. Lynn McClymont
- Toxicology
and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Annette H. Vogel
- Toxicology
and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Frank A. P. C. Gobas
- School
of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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3
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Yang PF, Ma WL, Xiao H, Hansen KM, Wang L, Sun JJ, Liu LY, Zhang ZF, Jia HL, Li YF. Temperature dependence of the rain-gas and snow-gas partition coefficients for nearly a thousand chemicals. CHEMOSPHERE 2024; 362:142565. [PMID: 38871187 DOI: 10.1016/j.chemosphere.2024.142565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 05/31/2024] [Accepted: 06/06/2024] [Indexed: 06/15/2024]
Abstract
Compared to the particle-gas partition coefficients (KPG), the rain-gas (KRG) and snow-gas (KSG) partition coefficients are also essential in studying the environmental behavior and fate of chemicals in the atmosphere. While the temperature dependence for the KPG have been extensively studied, the study for KRG and KSG are still lacking. Adsorption coefficients between water surface-air (KIA) and snow surface-air (KJA), as well as partition coefficients between water-air (KWA) and octanol-air (KOA) are vital in calculating KRG and KSG. These four basic adsorption and partition coefficients are also temperature-dependent, given by the well-known two-parameters Antoine equation logKXY = AXY + BXY/T, where KXY is the adsorption or partition coefficients, AXY and BXY are Antoine parameters (XY stand for IA, JA, WA, and OA), and T is the temperature in Kelvin. In this study, the parameters AXY and BXY are calculated for 943 chemicals, and logKXY can be estimated at any ambient temperature for these chemicals using these Antoine parameters. The results are evaluated by comparing these data with published experimental and modeled data, and the results show reasonable accuracy. Based on these coefficients, temperature-dependence of logKRG and logKSG is studied. It is found that both logKRG and logKSG are linearly related to 1/T, and Antoine parameters for logKRG and logKSG are also estimated. Distributions of the 943 chemicals in the atmospheric phases (gas, particle, and rain/snow), are illustrated in a Chemical Space Map. The findings reveal that, at environmental temperatures and precipitation days, the dominant state for the majority of chemicals is the gaseous phase. All the AXY and BXY values for logKSG, logKRG, and basic adsorption and partition coefficients, both modeled by this study and collected from published work, are systematically organized into an accessible dataset for public utilization.
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Affiliation(s)
- Pu-Fei Yang
- International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, China; Heilongjiang Provincial Key Laboratory of Polar Environment and Ecosystem (HPKL-PEE), Harbin, 150090, China; Department of Environmental Science, Aarhus University, Roskilde, 4000, Denmark
| | - Wan-Li Ma
- International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, China; Heilongjiang Provincial Key Laboratory of Polar Environment and Ecosystem (HPKL-PEE), Harbin, 150090, China
| | - Hang Xiao
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo, 315800, China
| | - Kaj M Hansen
- Department of Environmental Science, Aarhus University, Roskilde, 4000, Denmark
| | - Liang Wang
- Laboratory of Marine Ecological Environment Early Warning and Monitoring, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Jing-Jing Sun
- International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Li-Yan Liu
- International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, China; Heilongjiang Provincial Key Laboratory of Polar Environment and Ecosystem (HPKL-PEE), Harbin, 150090, China
| | - Zi-Feng Zhang
- International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, China; Heilongjiang Provincial Key Laboratory of Polar Environment and Ecosystem (HPKL-PEE), Harbin, 150090, China
| | - Hong-Liang Jia
- International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Yi-Fan Li
- International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology (PA-HIT), Harbin, 150090, China; Heilongjiang Provincial Key Laboratory of Polar Environment and Ecosystem (HPKL-PEE), Harbin, 150090, China; IJRC-PTS-NA, Toronto, ON, M2J 3N8, Canada.
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4
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Jyoti D, Sinha R. Physiological impact of personal care product constituents on non-target aquatic organisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167229. [PMID: 37741406 DOI: 10.1016/j.scitotenv.2023.167229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023]
Abstract
Personal care products (PCPs) are products used in cleaning, beautification, grooming, and personal hygiene. The rise in diversity, usage, and availability of PCPs has resulted in their higher accumulation in the environment. Thus, these constitute an emerging category of environmental contaminants due to the potential of its constituents (chemical and non-chemical) to induce various physiological effects even at lower concentrations (ng/L). For analyzing the impact of the PCPs constituents on the non-target organism about 300 article including research articles, review articles and guidelines were studied from 2000 to 2023. This review aims to firstly discuss the fate and accumulation of PCPs in the aquatic environment and organisms; secondly provides overview of environmental risks that are linked to PCPs; thirdly review the trends, current status of regulations and risks associated with PCPs and finally discuss the knowledge gaps and future perspectives for future research. The article discusses important constituents of PCPs such as antimicrobials, cleansing agents and disinfectants, fragrances, insect repellent, moisturizers, plasticizers, preservatives, surfactants, UV filters, and UV stabilizers. Each of them has been found to display certain toxic impact on the aquatic organisms especially the plasticizers and UV filters. These continuously and persistently release biologically active and inactive components which interferes with the physiological system of the non-target organism such as fish, corals, shrimps, bivalves, algae, etc. With a rise in the number of toxicity reports, concerns are being raised over the potential impacts of these contaminant on aquatic organism and humans. The rate of adoption of nanotechnology in PCPs is greater than the evaluation of the safety risk associated with the nano-additives. Hence, this review article presents the current state of knowledge on PCPs in aquatic ecosystems.
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Affiliation(s)
- Divya Jyoti
- School of Biological and Environmental Sciences, Shoolini University of Biotechnology and Management Science, Solan, India
| | - Reshma Sinha
- Department of Animal Sciences, School of Life Sciences, Central University of Himachal Pradesh, India.
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5
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Fremlin KM, Elliott JE, Letcher RJ, Harner T, Gobas FA. Developing Methods for Assessing Trophic Magnification of Perfluoroalkyl Substances within an Urban Terrestrial Avian Food Web. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:12806-12818. [PMID: 37590934 PMCID: PMC10469464 DOI: 10.1021/acs.est.3c02361] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/19/2023]
Abstract
We investigated the trophic magnification potential of perfluoroalkyl substances (PFAS) in a terrestrial food web by using a chemical activity-based approach, which involved normalizing concentrations of PFAS in biota to their relative biochemical composition in order to provide a thermodynamically accurate basis for comparing concentrations of PFAS in biota. Samples of hawk eggs, songbird tissues, and invertebrates were collected and analyzed for concentrations of 18 perfluoroalkyl acids (PFAAs) and for polar lipid, neutral lipid, total protein, albumin, and water content. Estimated mass fractions of PFCA C8-C11 and PFSA C4-C8 predominantly occurred in albumin within biota samples from the food web with smaller estimated fractions in polar lipids > structural proteins > neutral lipids and insignificant amounts in water. Estimated mass fractions of longer-chained PFAS (i.e., C12-C16) mainly occurred in polar lipids with smaller estimated fractions in albumin > structural proteins > neutral lipids > and water. Chemical activity-based TMFs indicated that PFNA, PFDA, PFUdA, PFDoA, PFTrDA, PFTeDA, PFOS, and PFDS biomagnified in the food web; PFOA, PFHxDA, and PFHxS did not appear to biomagnify; and PFBS biodiluted. Chemical activity-based TMFs for PFCA C8-C11 and PFSA C4-C8 were in good agreement with corresponding TMFs derived with concentrations normalized to only total protein in biota, suggesting that concentrations normalized to total protein may be appropriate proxies of chemical activity-based TMFs for PFAS, which predominantly partition to albumin. Similarly, TMFs derived with concentrations normalized to albumin may be suitable proxies of chemical activity-based TMFs for longer-chained PFAS, which predominantly partition to polar lipids.
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Affiliation(s)
- Katharine M. Fremlin
- Department
of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A
1S6, Canada
- Ecotoxicology
and Wildlife Health Division, Environment
and Climate Change Canada, 5421 Robertson Road, Delta, BC V4K 3N2, Canada
| | - John E. Elliott
- Department
of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A
1S6, Canada
- Ecotoxicology
and Wildlife Health Division, Environment
and Climate Change Canada, 5421 Robertson Road, Delta, BC V4K 3N2, Canada
| | - Robert J. Letcher
- Ecotoxicology
and Wildlife Health Division, National Wildlife Research Centre, Environment and Climate Change Canada, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1A
0H3, Canada
| | - Tom Harner
- Air
Quality Research Division, Environment and
Climate Change Canada, 4905 Dufferin Street, Toronto, ON M3H 5T4, Canada
| | - Frank A.P.C. Gobas
- Department
of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A
1S6, Canada
- School
of Resource and Environmental Management, Faculty of the Environment, Simon Fraser University, Burnaby, BC V5A
1S6, Canada
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6
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Wang WL, Zhang Y, Sun DM, Chen ZY, Qian M, Zhou Y, Feng XS, Zhang XY. Volatile Methylsiloxanes in Complex Samples: Recent Updates on Pretreatment and Analysis Methods. Crit Rev Anal Chem 2023:1-21. [PMID: 37603425 DOI: 10.1080/10408347.2023.2245050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Volatile methylsiloxanes (VMSs) are massively produced chemicals having applications in industry and home because of their physical and chemical characteristics. They are used in personal care products such as cosmetics, household coatings, cleaners, skin care products, and others. Resultantly, large number of VMSs are discharged into air where they can be subjected to atmospheric migrations over long distances causing toxic and estrogenic effects, persistence, and bioaccumulations. Many institutions have taken measures to control VMSs. They require accurate, rapid, and sensitive pretreatment and analysis methods for diverse samples. Herein, the pretreatment and determination methods of VMSs as reported in recent years are reviewed and summarized. Pretreatments include commonly methods such as membrane-assisted solvent extraction, liquid-liquid extraction, and others, while novel methods are solid phase extraction, solid phase microextraction, diverse liquid phase microextraction and others. Analyses are made through gas chromatography-based methods. In addition, the advantages, and disadvantages of techniques are compared, and the prospects of pretreatment and analysis methods are discussed.
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Affiliation(s)
- Wei-Lai Wang
- School of Pharmacy, China Medical University, Shenyang, China
| | - Yuan Zhang
- School of Pharmacy, China Medical University, Shenyang, China
| | - De-Mei Sun
- School of Pharmacy, China Medical University, Shenyang, China
| | - Zu-Yi Chen
- School of Pharmacy, China Medical University, Shenyang, China
| | - Min Qian
- School of Pharmacy, China Medical University, Shenyang, China
| | - Yu Zhou
- Department of Pharmacy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Song Feng
- School of Pharmacy, China Medical University, Shenyang, China
| | - Xin-Yuan Zhang
- School of Forensic Medicine, China Medical University, Shenyang, China
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7
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Galdi SM, Szczuka A, Shin C, Mitch WA, Luthy RG. Dissolved Methane Recovery and Trace Contaminant Fate Following Mainstream Anaerobic Treatment of Municipal Wastewater. ACS ES&T ENGINEERING 2023; 3:121-130. [PMID: 36660091 PMCID: PMC9841518 DOI: 10.1021/acsestengg.2c00256] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 06/01/2023]
Abstract
Anaerobic treatment of municipal wastewater with the staged anaerobic fluidized bed membrane bioreactor (SAF-MBR) shows promise to transform secondary wastewater treatment into an energy-positive process. However, the dissolved methane in SAF-MBR effluent needs to be recovered to reach net energy positive. To recover this methane for energy generation, an air stripping system was constructed downstream of a pilot-scale SAF-MBR facility and operated for over 80 days. The process removed 98% of effluent dissolved methane, and with the addition of intermittent disinfection recovered an average of 90% of the dissolved methane. The exit gas from air-stripping comprised 1.5-2.5% methane and could be utilized by blending with biogas produced from primary solids digestion and the SAF-MBR in an on-site combustion process. The direct energy costs for air stripping methane are <1% of the energy recoverable from the dissolved methane, not accounting for siloxane or sulfide scrubbing. Only siloxanes were observed at levels impacting combustion in this study, with 1.6 mg Si/m3 present in the blended biogas and air stripping mixture. The fate of a subset of trace organic contaminants was examined across the air stripping unit to check for aerobic degradation by methanotrophs or other opportunistic aerobes. Only 1,4-dioxane and benzotriazole showed statistically significant removal among 17 compounds screened, with 0.53 ± 0.13 and 0.34 ± 0.15 fraction removal, respectively. Our results indicate that air stripping is an energy efficient and robust technology for dissolved methane removal and onsite utilization for heat and electricity generation from anaerobic treatment of municipal wastewater.
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Affiliation(s)
- Stephen M. Galdi
- Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
| | - Aleksandra Szczuka
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
- University
of Michigan, 1351 Beal Avenue, Ann Arbor, Michigan48019, United
States
| | - Chungheon Shin
- Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
| | - William A. Mitch
- Civil
and Environmental Engineering, Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
| | - Richard G. Luthy
- Civil
and Environmental Engineering, Stanford
University, Stanford, California94305, United States
- NSF
Engineering Research Center for Re-inventing the Nation’s Urban
Water Infrastructure (ReNUWIt), https://www.renuwit.org/contact/
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8
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Gerhards R, Seston RM, Kozerski GE, McNett DA, Boehmer T, Durham JA, Xu S. Basic considerations to minimize bias in collection and analysis of volatile methyl siloxanes in environmental samples. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158275. [PMID: 36030859 DOI: 10.1016/j.scitotenv.2022.158275] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
Monitoring studies that aim to quantify volatile methyl siloxanes (VMS) in environmental matrices may encounter a multitude of issues, most of which relate to the unique combination of physical-chemical characteristics of VMS that distinguish them from other classes of organic compounds. These properties, which are critical to their function in various applications, also control their fate and distribution in the environment, as well as the analytical chemistry of their measurement. Polycondensation and rearrangement reactions of VMS oligomers are possible during sample storage and analysis. Thus, care should be exercised to suppress these types of reactions by avoiding any catalytic substances or surfaces in sample collection and analysis equipment. Another factor complicating sample integrity in the analysis of trace levels of VMS, is their ubiquitous presence in many common products and components of instrumentation in the laboratory. For example, some gas chromatography columns and inlet septa have been identified as sources of VMS due to surface-catalyzed transformation of silicones to VMS promoted by moisture under high temperature in some silicone-based GC columns. Possible chemical transformation of the analytes, contamination from other sources, and potential loss of analytes need to be assessed throughout all aspects of the study, from sample collection through analysis, by establishing a rigorous quality assurance and quality control program. The implementation of such a robust QA/QC program facilitates the identification and minimization of potential analytical biases and ensures the validity and usability of data generated from environmental monitoring campaigns for VMS. The objective of this paper is to focus on aspects of collection, processing, and analysis of environmental samples that may influence the quality of the VMS analytical results. This information should then be employed in the design and implementation of future monitoring studies and can used to assess the validity of analytical results from VMS monitoring studies.
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Affiliation(s)
| | - Rita M Seston
- Hyla Environmental Consulting, LLC, Midland, MI 48640, USA.
| | - Gary E Kozerski
- Toxicology & Environment Research and Consulting (TERC), The Dow Chemical Company, Midland, MI 48674, USA
| | - Debra A McNett
- Toxicology & Environment Research and Consulting (TERC), The Dow Chemical Company, Midland, MI 48674, USA
| | - Thomas Boehmer
- Evonik Operations GmbH, Analytical Laboratory, 45127 Essen, Germany
| | - Jeremy A Durham
- Toxicology & Environment Research and Consulting (TERC), The Dow Chemical Company, Midland, MI 48674, USA
| | - Shihe Xu
- Toxicology & Environment Research and Consulting (TERC), The Dow Chemical Company, Midland, MI 48674, USA
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9
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Eldos HI, Zouari N, Saeed S, Al-Ghouti MA. Recent advances in the treatment of PAHs in the environment: Application of nanomaterial-based technologies. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.103918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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10
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Bernardo F, Alves A, Homem V. A review of bioaccumulation of volatile methylsiloxanes in aquatic ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 824:153821. [PMID: 35167889 DOI: 10.1016/j.scitotenv.2022.153821] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Volatile methylsiloxanes (VMSs) are found in a broad range of industrial and consumer products. They are categorized as "high production volume chemicals" by the U.S. Environmental Protection Agency and listed as candidates of substances of very high concern in 2018, by the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Industrial wastewater and treated effluents may contain VMSs in different amounts, which can be discharged in the receptor media and may lead to environmental contamination. This can result in direct exposure to aquatic receptors in the water column or to benthic invertebrates from contact and/or ingestion of sediments, and indirect exposures through the aquatic food chain. The possible toxicological effects of VMSs for the aquatic biota and human ecology are not very well known since published information regarding this topic is scarce. VMSs have been subjected to regulatory scrutiny for environmental concerns and have already been screened to determine their environmental risk and ecological harm. This paper aims to assess VMSs bioaccumulation and potential biomagnification on food webs, using several bioaccumulation metrics. The result is a high-level overview of all the collected data, comparing the findings and the experimental conditions applied during the assessments. Several studies present conflicting results regarding the bioaccumulation categorization. Some aquatic organisms demonstrated a high bioconcentration and bioaccumulation of these contaminants. Trophic magnification factors (TMFs) have been suggested as the most reliable tool to assess a chemical behaviour in food webs. However, bioaccumulation studies in food webs provided mixed information, with some studies indicating trophic dilution and others presenting a potential of trophic biomagnification of VMSs. Efforts should be directed to obtain field-based levels of VMSs at different trophic levels and a wider range of linear VMSs should be analysed, since most studies focused on D4, D5 and D6.
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Affiliation(s)
- Fábio Bernardo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Arminda Alves
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Vera Homem
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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11
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Alton MW, Browne EC. Atmospheric Degradation of Cyclic Volatile Methyl Siloxanes: Radical Chemistry and Oxidation Products. ACS ENVIRONMENTAL AU 2022; 2:263-274. [PMID: 37102141 PMCID: PMC10114625 DOI: 10.1021/acsenvironau.1c00043] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cyclic volatile methyl siloxanes (cVMS) are anthropogenic chemicals that have come under scrutiny due to their widespread use and environmental persistence. Significant data on environmental concentrations and persistence of these chemicals exists, but their oxidation mechanism is poorly understood, preventing a comprehensive understanding of the environmental fate and impact of cVMS. We performed experiments in an environmental chamber to characterize the first-generation oxidation products of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5) under different peroxy radical fates (unimolecular reaction or bimolecular reaction with either NO or HO2) that approximate a range of atmospheric compositions. While the identity of the oxidation products from D3 changed as a function of the peroxy radical fate, the identity and yield of D4 and D5 oxidation products remained largely constant. We compare our results against the output from a kinetic model of cVMS oxidation chemistry. The reaction mechanism used in the model is developed using a combination of previously proposed cVMS oxidation reactions and standard atmospheric oxidation radical chemistry. We find that the model is unable to reproduce our measurements, particularly in the case of D4 and D5. The products that are poorly represented in the model help to identify possible branching points in the mechanism, which require further investigation. Additionally, we estimated the physical properties of the cVMS oxidation products using structure-activity relationships and found that they should not be significantly partitioned to organic or aqueous aerosol. The results suggest that cVMS first-generation oxidation products are also long-lived in the atmosphere and that environmental monitoring of these compounds is necessary to understand the environmental chemistry and loading of cVMS.
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Affiliation(s)
- Mitchell W. Alton
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Eleanor C. Browne
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
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12
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Whelan MJ, Kim J. Application of multimedia models for understanding the environmental behavior of volatile methylsiloxanes: Fate, transport, and bioaccumulation. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2022; 18:599-621. [PMID: 34375022 PMCID: PMC9293016 DOI: 10.1002/ieam.4507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/11/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Multimedia fate and transport models (MFTMs) describe how chemicals behave in the environment based on their inherent properties and the characteristics of receiving systems. We critically review the use of MFTMs for understanding the behavior of volatile methylsiloxanes (VMS). MFTMs have been used to predict the fate of VMS in wastewater treatment, rivers, lakes, marine systems, and the atmosphere, and to assess bioaccumulation and trophic transfers. More widely, they have been used to assess the overall persistence, long-range transport potential (LRTP), and the propensity for atmosphere-surface exchange. The application of MFTMs for VMS requires particularly careful selection of model inputs because the properties of VMS differ from those of most organic compounds. For example, although n-octanol/water partition coefficient (KOW ) values are high, air:water partition coefficient (KAW ) values are also high and n-octanol/air partition coefficient (KOA ) values are relatively low. In addition, organic carbon/water partition coefficient (KOC ) values are substantially lower than expectations based on KOW . This means that most empirical relationships between KOC and KOW are not appropriate. Good agreement between modeled and measured concentrations in air, sediment, and biota indicates that our understanding of environmental fate is reasonable. VMS compounds are "fliers" that principally partition to the atmosphere, implying high LRTP, although they have low redeposition potential. They are degraded in air (half-lives 3-10 days) and, thus, have low overall persistence. In water, exposure can be limited by hydrolysis, volatilization, and partitioning to sediments (where degradation half-lives are likely to be high). In food webs, they are influenced by metabolism in biota, which tends to drive trophic dilution (i.e., trophic magnification factors are often but not always <1). Key remaining uncertainties include the following: (i) the strength and direction of the temperature dependence for KOC ; (ii) the fate of atmospheric reaction products; and (iii) the magnitude of emissions to wastewater. Integr Environ Assess Manag 2022;18:599-621. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Michael J. Whelan
- Centre for Landscape and Climate Research, School of Geography, Geology and the EnvironmentUniversity of LeicesterLeicesterUK
| | - Jaeshin Kim
- Toxicology and Environmental Research and ConsultingThe Dow Chemical CompanyMidlandMichiganUSA
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13
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Delbecque N, Mascrez S, Psillakis E, Purcaro G. Sub-ambient temperature sampling of fish volatiles using vacuum-assisted headspace solid phase microextraction: Theoretical considerations and proof of concept. Anal Chim Acta 2022; 1192:339365. [DOI: 10.1016/j.aca.2021.339365] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 11/01/2022]
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14
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Salthammer T, Grimme S, Stahn M, Hohm U, Palm WU. Quantum Chemical Calculation and Evaluation of Partition Coefficients for Classical and Emerging Environmentally Relevant Organic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:379-391. [PMID: 34931808 DOI: 10.1021/acs.est.1c06935] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Octanol/water (KOW), octanol/air (KOA), and hexadecane/air (KHdA) partition coefficients are calculated for 67 organic compounds of environmental concern using computational chemistry. The extended CRENSO workflow applied here includes the calculation of extensive conformer ensembles with semiempirical methods and refinement through density functional theory, taking into account solvation models, especially COSMO-RS, and thermostatistical contributions. This approach is particularly advantageous for describing large and nonrigid molecules. With regard to KOW and KHdA, one can refer to many experimental data from direct and indirect measurement methods, and very good matches with results from our quantum chemical workflow are evident. In the case of the KOA values, however, good matches are only obtained for the experimentally determined values. Larger systematic deviations between data computed here and available, nonexperimental quantitative structure-activity relationship literature data occur in particular for phthalic acid esters and organophosphate esters. From a critical analysis of the coefficients calculated in this work and comparison with available literature data, we conclude that the presented quantum chemical composite approach is the most powerful so far for calculating reliable partition coefficients because all physical contributions to the conformational free energy are considered and the structure ensembles for the two phases are generated independently and consistently.
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Affiliation(s)
- Tunga Salthammer
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, 38108 Braunschweig, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany
| | - Marcel Stahn
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, 53115 Bonn, Germany
| | - Uwe Hohm
- Institute of Physical and Theoretical Chemistry, University of Braunschweig─Institute of Technology, 38106 Braunschweig, Germany
| | - Wolf-Ulrich Palm
- Institute of Sustainable and Environmental Chemistry, Leuphana University Lüneburg, 21335 Lüneburg, Germany
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15
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Xu S, Vogel A. Measuring snow scavenging of two airborne cyclic volatile methylsiloxanes under controlled conditions. CHEMOSPHERE 2021; 285:131291. [PMID: 34252803 DOI: 10.1016/j.chemosphere.2021.131291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
The objective of this study was to determine snow scavenging of cVMS and its potential effect on the cVMS concentrations in snowmelt water and surrounding soil. Snow scavenging of two cVMS, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5), was examined in two steps. First, sorption and desorption of D4 and D5 on snowflakes, including snow sorption coefficients (KiA), were measured against a benchmark compound, cyclopentanone, at different temperatures from 0 to -20 °C. Measurements were made using a custom-made snow chamber and 14C-labeled D4 and D5. In addition, the transfer of snow-bound cVMS to snowmelt water and surrounding soil was studied with 14C-D4 and 14C-D5-spiked snowpack placed both in a closed snow chamber and on top of a layer of frozen soil in an open chemical hood. KiA values measured in both sorption and desorption processes were very small (<10-2 m). They increased with decreasing temperature and were higher for the D5 compared to D4. The calculated gas scavenging of D4 and D5 was small because of the small KiA values, while particle scavenging of cVMS is predicted to be negligible due to their low octanol/air partition coefficients (KOA). Most importantly, almost all 14C-D4 and 14C-D5 sorbed by a snowpack was lost during the snow melting process through re-volatilization and hydrolysis and became non-detectable in snowmelt water. In short, the experimental measurements demonstrated that snow scavenging could not be a valid deposition mechanism for these volatile hydrophobic compounds.
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Affiliation(s)
- Shihe Xu
- Toxicology and Environmental Research and Consulting (TERC), Dow Chemical Company, Midland, MI, 48674, USA.
| | - Annette Vogel
- Toxicology and Environmental Research and Consulting (TERC), Dow Chemical Company, Midland, MI, 48674, USA
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16
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Tran DN, Park SM, Jung EM, Jeung EB. Prenatal Octamethylcyclotetrasiloxane Exposure Impaired Proliferation of Neuronal Progenitor, Leading to Motor, Cognition, Social and Behavioral Functions. Int J Mol Sci 2021; 22:12949. [PMID: 34884750 PMCID: PMC8657511 DOI: 10.3390/ijms222312949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/27/2021] [Accepted: 11/27/2021] [Indexed: 02/03/2023] Open
Abstract
Cyclic siloxane octamethylcyclotetrasiloxane (D4) has raised concerns as an endocrine-disrupting chemical (EDC). D4 is widely used in detergent products, cosmetics, and personal care products. Recently, robust toxicological data for D4 has been reported, but the adverse effects of D4 on brain development are unknown. Here, pregnant mice on gestational day 9.5 were treated daily with D4 to postnatal day 28, and the offspring mice were studied. The prenatal D4-treated mice exhibited cognitive dysfunction, limited memory, and motor learning defect. Moreover, prenatal D4 exposure reduced the proliferation of neuronal progenitors in the offspring mouse brain. Next, the mechanisms through which D4 regulated the cell cycle were investigated. Aberrant gene expression, such as cyclin-dependent kinases CDK6 and cyclin-dependent kinase inhibitor p27, were found in the prenatal D4-treated mice. Furthermore, the estrogen receptors ERa and ERb were increased in the brain of prenatal D4-treated mice. Overall, these findings suggest that D4 exerts estrogen activity that affects the cell cycle progression of neuronal progenitor cells during neurodevelopment, which may be associated with cognitive deficits in offspring.
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Affiliation(s)
- Dinh Nam Tran
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Korea; (D.N.T.); (S.-M.P.)
| | - Seon-Mi Park
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Korea; (D.N.T.); (S.-M.P.)
| | - Eui-Man Jung
- Laboratory of Molecular Developmental Biology, Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busandaehang-ro, 63beon-gil 2, Geumjeong-gu, Busan 46241, Korea;
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Korea; (D.N.T.); (S.-M.P.)
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17
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Baskaran S, Lei YD, Wania F. Reliable Prediction of the Octanol-Air Partition Ratio. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:3166-3180. [PMID: 34473856 PMCID: PMC9292506 DOI: 10.1002/etc.5201] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/29/2021] [Accepted: 08/29/2021] [Indexed: 05/12/2023]
Abstract
The octanol-air equilibrium partition ratio (KOA ) is frequently used to describe the volatility of organic chemicals, whereby n-octanol serves as a substitute for a variety of organic phases ranging from organic matter in atmospheric particles and soils, to biological tissues such as plant foliage, fat, blood, and milk, and to polymeric sorbents. Because measured KOA values exist for just over 500 compounds, most of which are nonpolar halogenated aromatics, there is a need for tools that can reliably predict this parameter for a wide range of organic molecules, ideally at different temperatures. The ability of five techniques, specifically polyparameter linear free energy relationships (ppLFERs) with either experimental or predicted solute descriptors, EPISuite's KOAWIN, COSMOtherm, and OPERA, to predict the KOA of organic substances, either at 25 °C or at any temperature, was assessed by comparison with all KOA values measured to date. In addition, three different ppLFER equations for KOA were evaluated, and a new modified equation is proposed. A technique's performance was quantified with the mean absolute error (MAE), the root mean square error (RMSE), and the estimated uncertainty of future predicted values, that is, the prediction interval. We also considered each model's applicability domain and accessibility. With an RMSE of 0.37 and a MAE of 0.23 for predictions of log KOA at 25 °C and RMSE of 0.32 and MAE of 0.21 for predictions made at any temperature, the ppLFER equation using experimental solute descriptors predicted the KOA the best. Even if solute descriptors must be predicted in the absence of experimental values, ppLFERs are the preferred method, also because they are easy to use and freely available. Environ Toxicol Chem 2021;40:3166-3180. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Sivani Baskaran
- Department of Physical and Environmental Sciences and Department of ChemistryUniversity of Toronto Scarborough, TorontoOntarioCanada
| | - Ying Duan Lei
- Department of Physical and Environmental Sciences and Department of ChemistryUniversity of Toronto Scarborough, TorontoOntarioCanada
| | - Frank Wania
- Department of Physical and Environmental Sciences and Department of ChemistryUniversity of Toronto Scarborough, TorontoOntarioCanada
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18
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Fremlin KM, Elliott JE, Martin PA, Harner T, Saini A, Gobas FAPC. Fugacity-Based Trophic Magnification Factors Characterize Bioaccumulation of Cyclic Methyl Siloxanes within an Urban Terrestrial Avian Food Web: Importance of Organism Body Temperature and Composition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13932-13941. [PMID: 34590828 DOI: 10.1021/acs.est.1c04269] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Trophic magnification of cyclic volatile methyl siloxanes (cVMS) in a terrestrial food web was investigated by measuring concentrations of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) and two reference chemicals within air and biota samples from an avian food web located in a mixed urban-agricultural landscape. Terrestrial trophic magnification factors derived from lipid normalized concentrations (TMFLs) for D5 and D6 were 0.94 (0.17 SE) and 1.1 (0.23 SE) and not statistically different from 1 (p > 0.05); however, the TMFL of D4 was 0.62 (0.11 SE) and statistically less than 1 (p < 0.001). TMFLs of PCB-153 and p,p'-DDE were 5.6 (2.2 SE) and 6.1 (2.8 SE) and statistically greater than 1 (p < 0.001). TMFLs of cVMS in this terrestrial system were similar to those reported in aquatic systems. However, trophic magnification factors derived on a fugacity basis (TMFFs), which recognize differences in body temperature and lipid composition between organisms, were greater than corresponding TMFLs primarily because a temperature-induced thermodynamic biomagnification of hydrophobic chemicals occurs when endothermic organisms consume poikilothermic organisms. Therefore, we recommend that biomagnification studies of food webs including endothermic and poikilothermic organisms incorporate differences in body temperature and tissue composition to accurately characterize the biomagnification potential of chemicals.
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Affiliation(s)
- Katharine M Fremlin
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada
| | - John E Elliott
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada
- Environment and Climate Change Canada, Pacific Wildlife Research Centre, 5421 Robertson Rd., R.R. #1, Delta, BC V4K 3N2, Canada
| | - Pamela A Martin
- Environment and Climate Change Canada, Canada Centre for Inland Waters, 867 Lakeshore Rd., Burlington, ON L7S 1A1, Canada
| | - Tom Harner
- Environment and Climate Change Canada, Air Quality Processes Research Section, 4905 Dufferin Street, Toronto, ON M3H 5T4, Canada
| | - Amandeep Saini
- Environment and Climate Change Canada, Air Quality Processes Research Section, 4905 Dufferin Street, Toronto, ON M3H 5T4, Canada
| | - Frank A P C Gobas
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada
- School of Resource and Environmental Management, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada
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19
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Xiang X, Liu N, Xu L, Cai Y. Review of recent findings on occurrence and fates of siloxanes in environmental compartments. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 224:112631. [PMID: 34416634 DOI: 10.1016/j.ecoenv.2021.112631] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/08/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
In view of their vast global usage in both consumer products and industrial processes, environmental emission and fates of siloxanes have become concerned issue. This review summarized the research progress, especially in the last decade, on production/consumption data, toxicities, analysis methods, environmental distribution, migration and degradation/transformation of both dimethylsiloxanes and modified siloxanes in atmospheric, aquatic and terrestrial compartments from various areas (especially in China). In spite of their fast degradation (hydrolysis and hydroxylation, etc) in various matrices (except sediment), dimethylsiloxane oligomers have been found in various environmental matrices from many countries due to their constant usage and emission. Moreover, recent literatures have paid attention to behaviors of dimethylsiloxanes in industrial areas, e.g., their higher residual levels compared with residential areas and unique transformed products (such as halogenated products) arose from special industrial production scenarios. Meanwhile, although most prior studies focused on dimethylsiloxanes, identification of modified-siloxanes with other functional groups in environment have been beginning to attract the attention of scientists. Furthermore, related literatures indicated that compared with dimethylsiloxanes, both halogenated-dimethylsiloxanes and modified methylsiloxanes (phenylsiloxanes and trifluoropropylsiloxanes) could have stronger persistence due to their weaker volatilization and degradation, especially in terrestrial matrices.
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Affiliation(s)
- Xiaoling Xiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Nannan Liu
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Lin Xu
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China
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20
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Li Q, Lv X, Wang X, Hu J, Wang X, Ma J. Typical indoor concentrations and mass flow of cyclic volatile methylsiloxanes (cVMSs) in Dalian, China. CHEMOSPHERE 2020; 248:126020. [PMID: 32041064 DOI: 10.1016/j.chemosphere.2020.126020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 01/16/2020] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Cyclic volatile methylsiloxaes (cVMSs), namely hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), were studied for a typical indoor environment of male and female dormitories in the campus of Dalian Maritime University (DMU) in China. An empty, frit-fitted SPE cartridge was placed on top of an Isolute ENV + cartridge, sampling cVMSs in particulate and gas phases, respectively. The highest concentration of D3, D4, D5, and D6 was 190, 460, 37,000, and 670 ng m-3, respectively. All cVMSs, especially D5, were higher in female dormitories than that in male dormitories. Emission rate from different sources of cVMSs in dormitories was calculated from a survey of the use of personal care products (PCPs) by students living in the dormitory during the sampling period. The mean emission rate (ER, mg·d-1) of D4 and D5 in male dormitories was 0.12 ± 0.01 and 0.49 ± 0.03 mg d-1, respectively, and that in female dormitories was 0.21 ± 0.05 and 46 ± 17 mg d-1, respectively. Then, we modified an existing mass balance model to predict the indoor air levels of D4 and D5 in both male and female dormitories based on the usage of PCPs. There was a good agreement for D4 and D5 concentrations in female dormitories between modeled and measured concentrations with the ratio of predicted to measured values to be 1.5 and 1.2, respectively, which indicated that use of PCPs was the main source of cVMSs in university dormitories.
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Affiliation(s)
- Qingbo Li
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Xiaoning Lv
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Xiaofeng Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Jiaochan Hu
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Xianyu Wang
- Queensland Alliance for Environmental Health Sciences, The University of Queensland, 20 Cornwall Street, Woolloongabba, Queensland, 4102, Australia
| | - Jianmin Ma
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
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21
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Panagopoulos Abrahamsson D, Warner NA, Jantunen L, Jahnke A, Wong F, MacLeod M. Investigating the presence and persistence of volatile methylsiloxanes in Arctic sediments. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:908-917. [PMID: 32048673 DOI: 10.1039/c9em00455f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Volatile methylsiloxanes (VMS) have been identified as contaminants of emerging concern in aquatic systems. Here, we report on the presence of VMS in sediment and wastewater from Arctic regions in 2014 to 2016 and model their persistence in Adventfjorden in Longyearbyen, Svalbard. Total concentrations of VMS in sediment were dominated by D4 and D5 and ranged from 0.0024 to 1.7 ng g-1 at Svalbard (Longyearbyen), from 4.0 to 43 ng g-1 in Greenland (Nuuk) and from 0.19 to 21 ng g-1 in the Canadian Archipelago. Concentrations in wastewater samples from Svalbard ranged from 12 to 156 ng L-1. Large variability in reported values of the partition ratio between organic carbon and water (KOC) and enthalpy of sorption (ΔHOC; often estimated from enthalpy of phase change between octanol and water, ΔHOW) of VMS has resulted in high uncertainty in evaluating persistence in aquatic systems. We evaluated previously reported KOC and ΔHOC values from the literature in predicting measured VMS concentrations in sediment and wastewater in scenarios using a fugacity-based multimedia model for VMS concentrations in Svalbard. We tested two different model scenarios: (1) KOC and ΔHOW measurements for three cyclic VMS previously reported by Kozerski et al. (Environ. Toxicol. Chem., 2014, 33, 1937-1945) and Xu and Kropscott (Environ. Chem., 2014, 33, 2702-2710) and (2) the KOC and ΔHOC measurements from Panagopoulos et al. (Environ. Sci. Technol., 2015, 49, 12161-12168 and Environ. Sci. Technol. Lett., 2017, 4(6), 240-245). Concentrations of VMS in sediment predicted from concentrations in wastewater in scenario 2 were in good agreement with measured concentrations, whereas in scenario 1, predicted concentrations were 2 to 4 orders of magnitude lower. Such large discrepancies indicate that the differences in the predicted concentrations are more likely to be attributed to KOC and ΔHOC than to uncertainty in environmental parameters or emission rates.
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Affiliation(s)
- Dimitri Panagopoulos Abrahamsson
- Department of Environmental Science and Analytical Chemistry, ACES, Stockholm University, Svante Arrhenius väg 8, SE-114 18 Stockholm, Sweden.
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Sakurai T, Imaizumi Y, Kuroda K, Hayashi TI, Suzuki N. Georeferenced multimedia environmental fate of volatile methylsiloxanes modeled in the populous Tokyo Bay catchment basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:843-853. [PMID: 31280166 DOI: 10.1016/j.scitotenv.2019.06.462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 06/09/2023]
Abstract
We investigated the multimedia fate of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in the densely populated catchment basin of Tokyo Bay, Japan, by using a georeferenced multimedia model. We estimated the daily per person consumption rate of these compounds in Japan according to literature. Emissions to the atmosphere accounted for almost all of the emissions of these compounds to the environment. The majority of these compounds was predicted to be distributed in the atmosphere (about 60%) and sediment (about 40%). The advective flows in and out of the atmosphere over the Tokyo Bay catchment basin dominated the flows of these compounds. The sewerage systems contributed considerably to the transport and fate of D5 and D6 in water. They transported these compounds from households to discharge outlets of sewage treatment plants (STPs), which in turn accounted for approximately one quarter of the emission of these compounds to rivers and to Tokyo Bay. The wastewater treatment plants also effectively removed these compounds from the wastewater. The overall persistence of D5 and D6 in the catchment basin was estimated to be 3.8-9.5 days. The horizontal distributions of these compounds were similar among environmental compartments; high concentrations were generally observed in populated areas. A sensitivity analysis demonstrated that the D5 discharge rate to Tokyo Bay excluding the direct discharge from STPs and the D5 mass in the river compartment were sensitive to changes of the organic-carbon-water partition coefficient. Comparison with the concentrations in rivers measured recently in the target area showed that the model captured overall trends of low to high concentrations in rivers. However, there was some variability and a bias toward underprediction. The model provided a better fit to measurements for D5 than for D6. One potential factor contributing to the bias toward underprediction was underestimation of the consumption rates.
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Affiliation(s)
- Takeo Sakurai
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
| | - Yoshitaka Imaizumi
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Keisuke Kuroda
- Fukushima Branch, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Tamura, Fukushima 963-7700, Japan; Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Takehiko I Hayashi
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Noriyuki Suzuki
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
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David V, Moldoveanu SC. Variation with temperature of octanol/water partition coefficient for the homologous series from benzene to propylbenzene. SEPARATION SCIENCE PLUS 2019. [DOI: 10.1002/sscp.201900033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Victor David
- University of Bucharest, Faculty of ChemistryDepartment of Analytical Chemistry Romania
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24
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Xu S. Extraction and quantitative analysis of water by GC/MS for trace-level dimethylsilanediol (DMSD). J Chromatogr A 2019; 1600:1-8. [PMID: 31036359 DOI: 10.1016/j.chroma.2019.04.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
Dimethylsilanediol (DMSD) is related to the most important bifunctional building block for silicone oligomers and polymers, although DMSD itself is not used in any commercial applications. The environmental release of DMSD is linked to the hydrolytic degradation of other silicone materials in soil and water as DMSD is usually one of the major products. Most common extraction and quantification methods are not suitable for the analysis of trace- and ultratrace-levels of DMSD in water. This is because DMSD is highly water soluble and can readily undergo self-condensation when concentrated. In addition, DMSD may also coexist with DMSD precusors such methylsiloxanes in water. In the present study, solid-phase extraction (SPE) in combination with gas chromatography-mass spectrometry (GC/MS) without pre-column derivatization was tested for analyzing water samples for DMSD. It was found that direct analysis by GC/MS can be used for a wide range of concentrations if DMSD was extracted into a dry organic solvent. Isolute® ENV + may be used for such extraction at higher DMSD concentrations, while Supelclean™ ENVI-Carb™ Plus was found to be better for trace and ultratrace analysis. Increased salt content in water can increase its DMSD extraction efficiency, while polarity of the eluting solvents is a determining factor for eluting efficiency. Moisture in the final extract is a detrimental factor for direct GC/MS analysis. With a proper moisture removal procedure and a suitable internal standard, coupling of SPE and direct GC/MS analysis reduces the method detection limits for DMSD to lower ppb levels. Based on field sample analysis, solvent and instrumental background, not instrumental sensitivity, was found to be the limiting factor in lowering the detection limits for this analysis.
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Affiliation(s)
- Shihe Xu
- Toxicology and Environmental Research and Consulting (TERC), Dow Chemical Company, Midland, MI, 48674, USA.
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25
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Xu S, Warner N, Bohlin-Nizzetto P, Durham J, McNett D. Long-range transport potential and atmospheric persistence of cyclic volatile methylsiloxanes based on global measurements. CHEMOSPHERE 2019; 228:460-468. [PMID: 31051348 DOI: 10.1016/j.chemosphere.2019.04.130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/11/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
This study investigates persistence (P) and long-range transport potential (LRTP) of cyclic volatile methylsiloxanes (cVMS) based on the field measurements in the Northern Hemisphere. The field data consisted of published outdoor air concentrations of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) at urban, suburban, rural and remote locations excluding the point sources. Three major trends were observed. First, D4 and D6 concentrations were correlated with measured concentrations for D5 at the same times and locations in the majority of the datasets, reflecting the common sources and similar removal mechanism(s) for these compounds. Second, as the sampling sites changed from the source to remote locations along a south-to-north transect, average cVMS concentrations in air decreased in an exponential manner. The empirical characteristic travel distances (eCTD) extracted from these spatial patterns were smaller than model estimated values and differed in order among individual compounds (D4 ∼ D5 < D6). Finally, D5/D6 concentration ratios were also found to decrease exponentially along the same spatial gradient, contrary to model predictions of an increase based on current knowledge of mechanisms controlling atmospheric cVMS degradation. These findings suggest that there may be additional removal process(es) for airborne cVMS, currently not accounted for, that requires further elucidation.
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Affiliation(s)
- Shihe Xu
- Toxicology and Environmental Research and Consulting (TERC), Dow Chemical Company, Midland, MI, 48674, USA.
| | - Nicholas Warner
- NILU-Norwegian Institute for Air Research, Fram Centre, Tromsø, N-9296, Norway
| | | | - Jeremy Durham
- Toxicology and Environmental Research and Consulting (TERC), Dow Chemical Company, Midland, MI, 48674, USA
| | - Debra McNett
- Toxicology and Environmental Research and Consulting (TERC), Dow Chemical Company, Midland, MI, 48674, USA
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26
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Whelan MJ, Kim J, Suganuma N, Mackay D. Uncertainty and equifinality in environmental modelling of organic pollutants with specific focus on cyclic volatile methyl siloxanes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1085-1098. [PMID: 31165835 DOI: 10.1039/c9em00099b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Multi-media fate and transport models (MFTMs) are invaluable tools in understanding and predicting the likely behaviour of organic pollutants in the environment. However, some parameters describing the properties of both the environmental system and the chemical pollutant under consideration are uncertain and or variable in space and time. Furthermore, model performance is often evaluated using sparse data sets on chemical concentrations in different media. This can result in equifinality - the phenomenon in which several different combinations of model parameters can result in similar predictions of environmental concentrations. We explore this idea for MFTMs for the first time using, as examples, three cyclic volatile methyl siloxanes (cVMS: D4, D5 and D6) and the QWASI lake model applied to Tokyo Bay. Monte Carlo simulation was employed with parameters selected from probability distributions representing estimated uncertainty in a large number of iterations. This generated distributions of predicted chemical concentrations in water (CW) and sediment (CS) which represent the aleatory uncertainty envelope but which also demonstrate significant equifinality. For all three compounds, the uncertainty implied in the CW was lower (coefficient of variation, CV, of the order of 20%) than for CS (CV ca. 45%), reflecting the propensity of cVMS compounds to sorb to sediment and the sensitivity of the model to KOC. Confidence intervals were particularly high for the persistence of D5 and D6 in sediment which both ranged between approximately 1.7 years and approximately 26 years for Tokyo Bay. Predicted concentration distributions matched observations well for D5 and D6 not for D4. Equifinality could be reduced by better constraining acceptable parameter sets using additional measured data from different environmental compartments.
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Affiliation(s)
- M J Whelan
- School of Geography, Geology and the Environment, University of Leicester, Leicester, UK.
| | - J Kim
- The Dow Chemical Company, Midland, Michigan, USA
| | | | - D Mackay
- Centre for Environmental Modelling and Chemistry, Trent University, Canada
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27
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Numviyimana C, Chmiel T, Kot-Wasik A, Namieśnik J. Study of pH and temperature effect on lipophilicity of catechol-containing antioxidants by reversed phase liquid chromatography. Microchem J 2019. [DOI: 10.1016/j.microc.2018.10.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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28
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Kim J, Mackay D, Whelan MJ. Predicted persistence and response times of linear and cyclic volatile methylsiloxanes in global and local environments. CHEMOSPHERE 2018; 195:325-335. [PMID: 29272801 DOI: 10.1016/j.chemosphere.2017.12.071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 12/08/2017] [Accepted: 12/11/2017] [Indexed: 06/07/2023]
Abstract
We investigated the response times of eight volatile methylsiloxanes (VMSs) in environmental systems at different scales from local to global, with a particular focus on overall loss rates after cessation of emissions. In part, this is driven by proposals to restrict the use of some of these compounds in certain products in Europe. The GloboPOP model estimated low absolute Arctic Contamination Potentials for all VMSs and rapid response times in all media except sediment. VMSs are predicted to be distributed predominantly in air where they react with OH radicals, leading to short response times. After cessation of emissions VMSs concentrations in the environment are expected to decrease rapidly from current levels. Response times in specific water and sediment systems were evaluated using a dynamic QWASI model. Response times were sensitive to both physico-chemical properties and environmental characteristics. Degradation was predicted to play the most important role in determining response times in water and sediment. In the case of the lowest molecular weight VMSs such as L2 and D3, response times were essentially independent of environmental characteristics due to fast hydrolysis in water and sediment. However, response times for the other VMSs are system-specific. They are relatively short in shallow water bodies but increase with depth due to the diminishing role of volatilization on concentration change as volume to surface area ratio increases. In sediment, degradation and resuspension rates also contribute most to the response times. The estimated response times for local environments are useful for planning future monitoring programs.
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Affiliation(s)
- Jaeshin Kim
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI, USA.
| | - Donald Mackay
- Department of Chemistry, Trent University, Peterborough, ON, Canada
| | - Michael John Whelan
- School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, United Kingdom
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29
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Panagopoulos D, MacLeod M. A critical assessment of the environmental fate of linear and cyclic volatile methylsiloxanes using multimedia fugacity models. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:183-194. [PMID: 29300410 DOI: 10.1039/c7em00524e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We apply multimedia models to systematically evaluate the fate profile of cyclic volatile methyl siloxanes (VMS) D4, D5 and D6, and the linear VMS L4 and L5 using recently reported measurements of their partition ratios between organic carbon and water (KOC), their salting out constants (Ks), and their enthalpy of sorption to organic carbon (ΔHOC). Our assessment follows a multi-stage strategy where the environmental fate of the chemicals is explored in generic regional models with increasing fidelity to the real system and in a region-specific model. Modeled emissions of VMS to air remained in air and were degraded or advected out of the system with overall residence times ranging from 2.4 to 2.5 days, while emissions to water resulted in accumulation in sediment and longer residence times ranging from 29.5 to 1120 days. When emitted to water the modeled residence times of VMS in the sediment exceeded the REACH criterion for persistence in freshwater sediments. Reported KOC measurements for D5 differ by 1 log unit, which results in a 500-day difference in the overall residence times calculated in the generic regional modeling. In the specific-region modeling assessment for Adventfjorden, Svalbard in Norway, the different KOC measurements of D5 resulted in a 200-day difference in overall residence times. Model scenarios that examined combinations of previously published ΔHOC or enthalpy of phase change between octanol and water (ΔHOW) for D5 in combination with the range of the KOC measurements resulted in 1100-days difference in overall residence times. Our results demonstrate that residence times of VMS in aquatic systems are highly sensitive to their degree of sorption to organic carbon, and that residence times of VMS likely exceed several persistence criteria and therefore they cannot be considered as non-persistent.
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Affiliation(s)
- Dimitri Panagopoulos
- Department of Environmental Science and Analytical Chemistry, ACES, Stockholm University, Svante Arrhenius väg 8, SE-114 18 Stockholm, Sweden. and Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, LBNL, 1 Cyclotron Road, 94720 Berkeley, California, USA
| | - Matthew MacLeod
- Department of Environmental Science and Analytical Chemistry, ACES, Stockholm University, Svante Arrhenius väg 8, SE-114 18 Stockholm, Sweden.
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30
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Metabolism of 14 C-octamethylcyclotetrasiloxane ([ 14 C]D 4 ) or 14 C-decamethylcyclopentasiloxane ([ 14 C]D 5 ) orally gavaged in rainbow trout ( Oncorhynchus mykiss ). Toxicol Lett 2017; 279 Suppl 1:115-124. [DOI: 10.1016/j.toxlet.2017.03.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/23/2017] [Accepted: 03/26/2017] [Indexed: 11/18/2022]
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31
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Metabolism and disposition of [ 14 C]-methylcyclosiloxanes in rats. Toxicol Lett 2017; 279 Suppl 1:98-114. [DOI: 10.1016/j.toxlet.2017.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/31/2017] [Accepted: 05/02/2017] [Indexed: 11/18/2022]
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32
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Krogseth IS, Whelan MJ, Christensen GN, Breivik K, Evenset A, Warner NA. Understanding of Cyclic Volatile Methyl Siloxane Fate in a High Latitude Lake Is Constrained by Uncertainty in Organic Carbon-Water Partitioning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:401-409. [PMID: 27997187 DOI: 10.1021/acs.est.6b04828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Cyclic volatile methyl siloxanes (cVMS) are emitted to aquatic environments with wastewater effluents. Here, we evaluate the environmental behavior of three cVMS compounds (octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6)) in a high latitude lake (Storvannet, 70°N 23°E), experiencing intermittent wastewater emissions and high latitude environmental conditions (low temperatures and seasonal ice cover). Measured cVMS concentrations in lake water were below detection limits in both March and June 2014. However, mean concentrations in sediments were 207 ± 30, 3775 ± 973 and 848 ± 211 ng g-1 organic carbon for D4, D5 and D6, respectively. To rationalize measurements, a fugacity-based model for lakes (QWASI) was parametrized for Storvannet. The key removal process for cVMS from the lake was predicted to be advection due to the low hydraulic retention time of the lake, followed by volatilization. Predicted cVMS behavior was highly sensitive to the partition coefficient between organic carbon and water (KOC) and its temperature dependence. Predictions indicated lower overall persistence with decreasing temperature due to enhanced partitioning from sediments to water. Inverse modeling to predict steady-state emissions from cVMS concentrations in sediment provided unrealistically high emissions, when evaluated against measured concentrations in sewage. However, high concentrations of cVMS in sediment and low concentrations in water could be explained via a hypothetical dynamic emission scenario consistent with combined sewer overflows. The study illustrates the importance of considering compound-specific behavior of emerging contaminants that may differ from legacy organic contaminants.
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Affiliation(s)
- Ingjerd Sunde Krogseth
- NILU - Norwegian Institute for Air Research, The Fram Centre , P.O. Box 6606 Langnes, 9296 Tromsø, Norway
| | - Michael John Whelan
- Department of Geography, University of Leicester , Leicester LE1 7RH, United Kingdom
| | | | - Knut Breivik
- NILU - Norwegian Institute for Air Research , P.O. Box 100, 2027 Kjeller, Norway
- Department of Chemistry, University of Oslo , P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Anita Evenset
- Akvaplan-niva AS, The Fram Centre , P.O. Box 6606 Langnes, 9296 Tromsø, Norway
| | - Nicholas Alexander Warner
- NILU - Norwegian Institute for Air Research, The Fram Centre , P.O. Box 6606 Langnes, 9296 Tromsø, Norway
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33
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Giesy JP, Solomon KR, Kacew S, Mackay D, Stobo G, Kennedy S. The case for establishing a board of review for resolving environmental issues: The science court in Canada. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2016; 12:572-579. [PMID: 26460810 DOI: 10.1002/ieam.1729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/30/2015] [Accepted: 10/09/2015] [Indexed: 06/05/2023]
Abstract
Technology and scientific advancements are accelerating changes in society at a pace that is challenging the abilities of government regulatory agencies and legal courts to understand the benefits and costs of these changes to humans, wildlife, and their environments. The social, economic, and political facets of concern, such as the potential effects of chemicals, complicate the preparation of regulatory standards and practices intended to safeguard the public. Court judges and attorneys and, in some cases, lay juries are tasked with interpreting the data and implications underlying these new advancements, often without the technical background necessary to understand complex subjects and subsequently make informed decisions. Here, we describe the scientific-quasi-judicial process adopted in Canada under the Canadian Environmental Protection Act, 1999, which could serve as a model for resolving conflicts between regulatory agencies and the regulated community. An example and process and lessons learned from the first Board of Review, which was for decamethylcyclopentasiloxane (D5; CAS# 541-02-06), are provided. Notable among these lessons are: 1) the need to apply state-of-the-science insights into the regulatory process, 2) to encourage agencies to continuously review and update their assessment processes, criteria, and models, and 3) provide these processes in guidance documents that are transparent and available to all stakeholders and generally foster closer cooperation between regulators, the academic community, industry, and nongovernment organizations (NGOs). Integr Environ Assess Manag 2016;12:572-579. © 2015 SETAC.
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Affiliation(s)
- John P Giesy
- Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Zoology, and Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
- Department of Biology and Chemistry and State Key Laboratory in Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, SAR, China
- School of Biological Sciences, University of Hong Kong, Hong Kong, SAR, China
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, People's Republic of China
| | - Keith R Solomon
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Sam Kacew
- McLauglin Centre for Health Risk Assessment, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Gerald Stobo
- Borden Ladner Gervais LLP, World Exchange Plaza, Ottawa, Ontario, Canada
| | - Steven Kennedy
- Cassels Brock and Blackwell LLP, Toronto, Ontario, Canada
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34
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Tansel B, Surita SC. Selectivity and limitations of carbon sorption tubes for capturing siloxanes in biogas during field sampling. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 52:122-129. [PMID: 27055363 DOI: 10.1016/j.wasman.2016.03.057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 03/30/2016] [Accepted: 03/30/2016] [Indexed: 06/05/2023]
Abstract
Siloxane levels in biogas can jeopardize the warranties of the engines used at the biogas to energy facilities. The chemical structure of siloxanes consists of silicon and oxygen atoms, alternating in position, with hydrocarbon groups attached to the silicon side chain. Siloxanes can be either in cyclic (D) or linear (L) configuration and referred with a letter corresponding to their structure followed by a number corresponding to the number of silicon atoms present. When siloxanes are burned, the hydrocarbon fraction is lost and silicon is converted to silicates. The purpose of this study was to evaluate the adequacy of activated carbon gas samplers for quantitative analysis of siloxanes in biogas samples. Biogas samples were collected from a landfill and an anaerobic digester using multiple carbon sorbent tubes assembled in series. One set of samples was collected for 30min (sampling 6-L gas), and the second set was collected for 60min (sampling 12-L gas). Carbon particles were thermally desorbed and analyzed by Gas Chromatography Mass Spectrometry (GC/MS). The results showed that biogas sampling using a single tube would not adequately capture octamethyltrisiloxane (L3), hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6). Even with 4 tubes were used in series, D5 was not captured effectively. The single sorbent tube sampling method was adequate only for capturing trimethylsilanol (TMS) and hexamethyldisiloxane (L2). Affinity of siloxanes for activated carbon decreased with increasing molecular weight. Using multiple carbon sorbent tubes in series can be an appropriate method for developing a standard procedure for determining siloxane levels for low molecular weight siloxanes (up to D3). Appropriate quality assurance and quality control procedures should be developed for adequately quantifying the levels of the higher molecular weight siloxanes in biogas with sorbent tubes.
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Affiliation(s)
- Berrin Tansel
- Department of Civil and Environmental Engineering, Florida International University, College of Engineering and Computing, 10155 West Flagler St, Miami, FL 33174, United States.
| | - Sharon C Surita
- Department of Civil and Environmental Engineering, Florida International University, College of Engineering and Computing, 10155 West Flagler St, Miami, FL 33174, United States
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Mackay D, Cowan-Ellsberry CE, Powell DE, Woodburn KB, Xu S, Kozerski GE, Kim J. Decamethylcyclopentasiloxane (D5) environmental sources, fate, transport, and routes of exposure. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2015. [PMID: 26213270 DOI: 10.1002/etc.2941] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The environmental sources, fate, transport, and routes of exposure of decamethylcyclopentasiloxane (D5; CAS no. 541-02-6) are reviewed in the present study, with the objective of contributing to effective risk evaluation and assessment of this and related substances. The present review, which is part of a series of studies discussing aspects of an effective risk evaluation and assessment, was prompted in part by the findings of a Board of Review undertaken to comment on a decision by Environment Canada made in 2008 to subject D5 to regulation as a toxic substance. The present review focuses on the early stages of the assessment process and how information on D5's physical-chemical properties, uses, and fate in the environment can be integrated to give a quantitative description of fate and exposure that is consistent with available monitoring data. Emphasis is placed on long-range atmospheric transport and fate in water bodies receiving effluents from wastewater treatment plants (along with associated sediments) and soils receiving biosolids. The resulting exposure estimates form the basis for assessments of the resulting risk presented in other studies in this series. Recommendations are made for developing an improved process by which D5 and related substances can be evaluated effectively for risk to humans and the environment.
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Affiliation(s)
| | | | | | | | - Shihe Xu
- Dow Corning, Midland, Michigan, USA
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36
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Mackay D, Powell DE, Woodburn KB. Bioconcentration and Aquatic Toxicity of Superhydrophobic Chemicals: A Modeling Case Study of Cyclic Volatile Methyl Siloxanes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:11913-11922. [PMID: 26352906 DOI: 10.1021/acs.est.5b03195] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Many chemicals in commerce are classified as "superhydrophobic", having log octanol-water partition coefficients (log KOW) approaching or exceeding 7. Examples include long-chain alkanes, halogenated aromatics, and cyclic volatile methylsiloxanes (cVMS). We show that superhydrophobic chemicals present unique assessment challenges because of their sparing solubility in water and difficulties in empirical determinations of bioconcentration factors (BCFs) and aquatic toxicity. Using cVMS as an example, BCFs are considerably lower than expected due to biotransformation. Reviewed aquatic toxicity test data for cVMS in a range of aquatic organisms show little or no toxic effects up to solubility limits in water and sediment. Explanations for this apparent lack of toxicity of cVMS, and by extension to other superhydrophobic chemicals, are explored using a conventional one-compartment uptake model to simulate bioconcentration and toxicity tests using an assumed baseline narcotic critical body residue (CBR) and a range of organism sizes. Because of the low aqueous concentrations, equilibration times are very long and BCFs are sensitive to even very slow rates of biotransformation. Most organisms fail to achieve the assumed CBR during feasible test durations even at the solubility limit. Regulatory evaluation of superhydrophobic substances requires specially designed test protocols addressing biotransformation and dietary uptake.
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Affiliation(s)
- Donald Mackay
- Centre for Environmental Modelling and Chemistry, Trent University , Peterborough, ON K9J 7B8, Canada
| | - David E Powell
- Dow Corning Corporation , Health and Environmental Sciences, Auburn, Michigan 48611, United States
| | - Kent B Woodburn
- Dow Corning Corporation , Health and Environmental Sciences, Auburn, Michigan 48611, United States
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