This page has only limited features, please log in for full access.
Source attribution of airborne particulate matter (PM) relies on a host of different chemical species. Organic molecular markers are a set of particularly useful marker compounds for estimating source contributions to the fine PM fraction (i.e., PM2.5). Although there are many source apportionment studies based on organic markers, these studies heavily rely on the few studies that report region-specific emission profiles. Source attribution efforts, particularly those conducted in countries with emerging economies, benefit from ad hoc information to conduct the corresponding analyses. In this study, we report organic molecular marker source profiles for PM2.5 emitted from 12 major sources types from five general source categories (meat cooking operations, vehicle exhausts, industries, biomass and trash burning, and urban background) for the Monterrey Metropolitan Area (Mexico). Source emission samples were obtained from a ground-based source-dominated sampling approach. Filter-based instruments were utilized, and the loaded filters were chemically characterized for organic markers by GC-MS. Levoglucosan and cholesterol dominate charbroiled-cooking operation sources while methoxyphenols, PAHs and hopanes dominate open-waste burning, vehicle exhaust and industrial emissions, respectively. A statistical analysis showed values of the Pearson distance < 0.4 and the similarity identity distance > 0.8 in all cases, indicating dissimilar source profiles. This was supported by the coefficient of divergence average values that ranged from 0.62 to 0.72. These profiles could further be utilized in receptor models to conduct source apportionment in regions with similar characteristics and can also be used to develop air pollution abatement strategies.
Yasmany Mancilla; Gerardo Medina; Lucy González; Pierre Herckes; Matthew Fraser; Alberto Mendoza. Determination and Similarity Analysis of PM2.5 Emission Source Profiles Based on Organic Markers for Monterrey, Mexico. Atmosphere 2021, 12, 554 .
AMA StyleYasmany Mancilla, Gerardo Medina, Lucy González, Pierre Herckes, Matthew Fraser, Alberto Mendoza. Determination and Similarity Analysis of PM2.5 Emission Source Profiles Based on Organic Markers for Monterrey, Mexico. Atmosphere. 2021; 12 (5):554.
Chicago/Turabian StyleYasmany Mancilla; Gerardo Medina; Lucy González; Pierre Herckes; Matthew Fraser; Alberto Mendoza. 2021. "Determination and Similarity Analysis of PM2.5 Emission Source Profiles Based on Organic Markers for Monterrey, Mexico." Atmosphere 12, no. 5: 554.
1H and 13C NMR can inform on the impurities in commercial polyDADMAC solutions and enable mechanistic NDMA formation studies.
Samantha Donovan; Ariel Jasmine Atkinson; Natalia Fischer; Amelia E. Taylor; Johann Kieffer; Jean-Philippe Croue; Paul Westerhoff; Pierre Herckes. Nuclear magnetic resonance enables understanding of polydiallyldimethylammonium chloride composition and N-nitrosodimethylamine formation during chloramination. Environmental Science: Water Research & Technology 2021, 7, 1050 -1059.
AMA StyleSamantha Donovan, Ariel Jasmine Atkinson, Natalia Fischer, Amelia E. Taylor, Johann Kieffer, Jean-Philippe Croue, Paul Westerhoff, Pierre Herckes. Nuclear magnetic resonance enables understanding of polydiallyldimethylammonium chloride composition and N-nitrosodimethylamine formation during chloramination. Environmental Science: Water Research & Technology. 2021; 7 (6):1050-1059.
Chicago/Turabian StyleSamantha Donovan; Ariel Jasmine Atkinson; Natalia Fischer; Amelia E. Taylor; Johann Kieffer; Jean-Philippe Croue; Paul Westerhoff; Pierre Herckes. 2021. "Nuclear magnetic resonance enables understanding of polydiallyldimethylammonium chloride composition and N-nitrosodimethylamine formation during chloramination." Environmental Science: Water Research & Technology 7, no. 6: 1050-1059.
The recent discovery of magnetic nanoparticles (NPs) in human brain tissue has raised concerns regarding their source and neurotoxicity. As previous studies have suggested that magnetite in urban dust may be the source, we collected and thoroughly characterized the nature of ambient urban magnetic dust particles prior to investigating their neurotoxic potential. In addition to magnetite NPs, magnetic dust contained an abundance (~40%) of elemental iron (Fe0) in inhalable (<10 µm) and nanoscale (<200 nm) size ranges with these particles small enough to enter the human brain via the respiratory tract and olfactory bulbs. The magnetic dust also contained non-ferrous water-soluble metals (particularly Cu) that can induce formation of reactive oxygen species (ROS). Previous studies used engineered pure-magnetite for in vitro ROS studies. However, while magnetite was present in all magnetic dust particles collected, engineered pure-magnatite was relatively unreactive and contributed minimally to the generation of ROS. We fill a critical knowledge gap between exposure to heterogeneous ambient iron-particles and in vitro experiments with engineered versus ambient, incidental iron-bearing nano-scale minerals. Our work points to the need to further investigate the presence and properties of magnetic NPs in respirable dust with respect to their potential role in neurodegeneration.
Xiangxing Long; Yi-Hao Luo; Zhaobo Zhang; Chenwei Zheng; Chao Zeng; Yuqiang Bi; Chen Zhou; Bruce E. Rittmann; T. David Waite; Pierre Herckes; Paul Westerhoff. Nature and Oxidative Reactivity of Urban Magnetic Nanoparticle Dust Provide New Insights into Potential Neurotoxicity Studies. Environmental Science & Technology 2020, 54, 1 .
AMA StyleXiangxing Long, Yi-Hao Luo, Zhaobo Zhang, Chenwei Zheng, Chao Zeng, Yuqiang Bi, Chen Zhou, Bruce E. Rittmann, T. David Waite, Pierre Herckes, Paul Westerhoff. Nature and Oxidative Reactivity of Urban Magnetic Nanoparticle Dust Provide New Insights into Potential Neurotoxicity Studies. Environmental Science & Technology. 2020; 54 (17):1.
Chicago/Turabian StyleXiangxing Long; Yi-Hao Luo; Zhaobo Zhang; Chenwei Zheng; Chao Zeng; Yuqiang Bi; Chen Zhou; Bruce E. Rittmann; T. David Waite; Pierre Herckes; Paul Westerhoff. 2020. "Nature and Oxidative Reactivity of Urban Magnetic Nanoparticle Dust Provide New Insights into Potential Neurotoxicity Studies." Environmental Science & Technology 54, no. 17: 1.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an elusive and highly pathogenic agent, has resulted in the ongoing COVID-19 pandemic affecting numerous populations worldwide. New studies investigating the tenacity of SARS-CoV-2 have highlighted its ability to persist on a myriad of surfaces for several days, including gowns and shoes. As a result, there is a global need for sterilization of a variety of potentially-contaminated items, ranging from clothing to personal protective equipment like face coverings. To this end, we have designed and constructed a cost-effective, scalable, and sustainable sterilization system that uses ozone gas to inactivate viral particles. We sought to determine the efficacy of the system in the sterilization of viral particles as well as its ability to sterilize N95 respirators for reuse. N95 respirators inoculated with P22 bacteriophage and sterilized in the ozone system showed a 6-log10 reduction in viral load when treated at 25 ppm for 150 minutes. Further, N95 respirators treated with five 150-minute cycles at 35 ppm for a total concentration-time product (CT) of 26,250 ppm min in the ozone system showed comparable filtration efficiency to untreated N95 respirators in a 50 to 200 nmr particulate challenge filtration test. Interestingly, the surgical N95 respirators tested showed complete inactivation of fluid resistance and degradation of the elasticity of polyisoprene straps after five cycles in the sterilization system. Taken together, these data suggest that while our ozone system may negatively affect certain protective aspects of surgical N95 respirators, it does effectively sterilize viral particles and can be utilized for a multitude of other use cases, including sterilizing polypropylene face coverings after potential SARS-CoV-2 contamination. In addition to providing long-term environmental benefits, deployment of this system during the ongoing pandemic reduces the risk of COVID-19 community transmission while conserving monetary resources otherwise spent on the continuous purchase of disposable face coverings.
Nikhil Dave; Katie Sue Pascavis; John M Patterson; Michael Kozicki; David W Wallace; Abhik Chowdhury; Morteza Abbaszadegan; Absar Alum; Pierre Herckes; Zhaobo Zhang; Josh Chang; Clinton Ewell; Tyler Smith; Mark Naufel. Characterization of a novel, low-cost, scalable ozone gas system for sterilization of N95 respirators and other COVID-19 related use cases. 2020, 1 .
AMA StyleNikhil Dave, Katie Sue Pascavis, John M Patterson, Michael Kozicki, David W Wallace, Abhik Chowdhury, Morteza Abbaszadegan, Absar Alum, Pierre Herckes, Zhaobo Zhang, Josh Chang, Clinton Ewell, Tyler Smith, Mark Naufel. Characterization of a novel, low-cost, scalable ozone gas system for sterilization of N95 respirators and other COVID-19 related use cases. . 2020; ():1.
Chicago/Turabian StyleNikhil Dave; Katie Sue Pascavis; John M Patterson; Michael Kozicki; David W Wallace; Abhik Chowdhury; Morteza Abbaszadegan; Absar Alum; Pierre Herckes; Zhaobo Zhang; Josh Chang; Clinton Ewell; Tyler Smith; Mark Naufel. 2020. "Characterization of a novel, low-cost, scalable ozone gas system for sterilization of N95 respirators and other COVID-19 related use cases." , no. : 1.
Due to the virulence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen responsible for the respiratory disease termed COVID-19, there has been a significant increase in demand for surgical masks and N95 respirators in medical clinics as well as within communities operating during the COVID-19 epidemic. Thus, community members, business owners, and even medical personnel have resorted to alternative methods for sterilizing face coverings and N95 respirators for reuse. While significant work has shown that vaporized hydrogen peroxide (VHP) can be used to sterilize N95 respirators, the cost and installation time for these sterilization systems limit their accessibility. To this end, we have designed and constructed a novel, cost-effective, and scalable VHP system that can be used to sterilize N95 respirators and other face coverings for clinical and community applications. N95 respirators inoculated with P22 bacteriophage showed a greater than 6-log10 reduction in viral load when sterilized in the VHP system for one 60-minute cycle. Further, N95 respirators treated with 20 cycles in this VHP system showed comparable filtration efficiency to untreated N95 respirators in a 50 to 200 nanometer particulate challenge filtration test. While a 23% average increase in water droplet roll-off time was observed for N95 respirators treated with 5 cycles in the sterilization, no breakdown in fluid resistance was detected. These data suggest that our VHP system is effective in sterilizing N95 respirators and other polypropylene masks for reuse. Relating to the present epidemic, deployment of this system reduces the risk of COVID-19 community transmission while conserving monetary resources otherwise spent on the continuous purchase of disposable N95 respirators and other face coverings. In summary, this novel, scientifically validated sterilization system can be easily built at a low cost and implemented in a wide range of settings.
Nikhil Dave; Katie Sue Pascavis; John M Patterson; David W Wallace; Abhik Chowdhury; Morteza Abbaszadegan; Absar Alum; Pierre Herckes; Zhaobo Zhang; Michael Kozicki; Erica Forzani; Sabrina Jimena Mora; Josh Chang; Clinton Ewell; Tyler Smith; Mark Naufel. Characterization of a novel, low-cost, scalable vaporized hydrogen peroxide system for sterilization of N95 respirators and other COVID-19 related personal protective equipment. 2020, 1 .
AMA StyleNikhil Dave, Katie Sue Pascavis, John M Patterson, David W Wallace, Abhik Chowdhury, Morteza Abbaszadegan, Absar Alum, Pierre Herckes, Zhaobo Zhang, Michael Kozicki, Erica Forzani, Sabrina Jimena Mora, Josh Chang, Clinton Ewell, Tyler Smith, Mark Naufel. Characterization of a novel, low-cost, scalable vaporized hydrogen peroxide system for sterilization of N95 respirators and other COVID-19 related personal protective equipment. . 2020; ():1.
Chicago/Turabian StyleNikhil Dave; Katie Sue Pascavis; John M Patterson; David W Wallace; Abhik Chowdhury; Morteza Abbaszadegan; Absar Alum; Pierre Herckes; Zhaobo Zhang; Michael Kozicki; Erica Forzani; Sabrina Jimena Mora; Josh Chang; Clinton Ewell; Tyler Smith; Mark Naufel. 2020. "Characterization of a novel, low-cost, scalable vaporized hydrogen peroxide system for sterilization of N95 respirators and other COVID-19 related personal protective equipment." , no. : 1.
The COVID-19 pandemic is increasing the need for personal protective equipment (PPE) worldwide, including the demand for facial masks used by healthcare workers. Disinfecting and reusing these masks may offer benefits in the short term to meet urgent demand. Germicidal ultraviolet light provides a nonchemical, easily deployable technology capable of achieving inactivation of H1N1 virus on masks. Working with N95-rated masks and nonrated surgical masks, we demonstrated that neither 254 nor 265 nm UV-C irradiation at 1 and 10 J/cm2 had adverse effects on the masks’ ability to remove aerosolized virus-sized particles. Additional testing showed no change in polymer structure, morphology, or surface hydrophobicity for multiple layers in the masks and no change in pressure drop or tensile strength of the mask materials. Results were similar when applying 254 nm low-pressure UV lamps and 265 nm light-emitting diodes. On the basis of the input from healthcare workers and our findings, a treatment system and operational manual were prepared to enable treatment and reuse of N95 facial masks. Knowledge gained during this study can inform techno-economic analyses for treating and reusing masks or lifecycle assessments of options to reduce the enormous waste production of single-use PPE used in the healthcare system, especially during pandemics.
Zhe Zhao; Zhaobo Zhang; Mariana Lanzarini-Lopes; Shahnawaz Sinha; Hojung Rho; Pierre Herckes; Paul Westerhoff. Germicidal Ultraviolet Light Does Not Damage or Impede Performance of N95 Masks Upon Multiple Uses. Environmental Science & Technology Letters 2020, 7, 600 -605.
AMA StyleZhe Zhao, Zhaobo Zhang, Mariana Lanzarini-Lopes, Shahnawaz Sinha, Hojung Rho, Pierre Herckes, Paul Westerhoff. Germicidal Ultraviolet Light Does Not Damage or Impede Performance of N95 Masks Upon Multiple Uses. Environmental Science & Technology Letters. 2020; 7 (8):600-605.
Chicago/Turabian StyleZhe Zhao; Zhaobo Zhang; Mariana Lanzarini-Lopes; Shahnawaz Sinha; Hojung Rho; Pierre Herckes; Paul Westerhoff. 2020. "Germicidal Ultraviolet Light Does Not Damage or Impede Performance of N95 Masks Upon Multiple Uses." Environmental Science & Technology Letters 7, no. 8: 600-605.
Inorganic carbonate can be an important component of atmospheric particulate matter in arid environments where mineral dust components contribute significantly to air particulate matter. Carbonate carbon (CC) is only rarely quantified in atmospheric studies and methods to quantify carbonate in atmospheric samples are rare. In this manuscript, we present a novel protocol for quantifying carbonate carbon in atmospheric particulate matter samples, through the acidification of aerosol filters at ambient pressure and temperature and subsequent measurement of carbon dioxide (CO2) released upon acidification. This method is applicable to a variety of filter media used in air pollution studies, such as Teflon, cellulose, or glass fiber filters. The method allows the customization of the filter area used for analysis (up to 24 cm2) so that sufficient CO2 can be detected when released and to assure that the sample aliquot is representative of the whole filter. The resulting detection limits can be as low as 0.12 µg/cm2. The analysis of a known amount of sodium bicarbonate applied to a filter resulted in a relative error within 15% of the known mass of bicarbonate when measured 20 min after acidification. A particulate matter sample with aerodynamic diameter larger than 2.5 µm (PM>2.5) collected via cascade impaction on a high-volume aerosol sampler yielded good precision, with a CC concentration of 4.4 ± 0.3 µgC/cm2 for six replicates. The precision, accuracy, and reproducibility of this method of CC measurement make it a good alternative to existing quantification methods.
Denise C. Napolitano; Hilairy E. Hartnett; Pierre Herckes. A Novel Method for Carbonate Quantification in Atmospheric Particulate Matter. Atmosphere 2020, 11, 661 .
AMA StyleDenise C. Napolitano, Hilairy E. Hartnett, Pierre Herckes. A Novel Method for Carbonate Quantification in Atmospheric Particulate Matter. Atmosphere. 2020; 11 (6):661.
Chicago/Turabian StyleDenise C. Napolitano; Hilairy E. Hartnett; Pierre Herckes. 2020. "A Novel Method for Carbonate Quantification in Atmospheric Particulate Matter." Atmosphere 11, no. 6: 661.
There is significant iron deposition in the oceans, approximately 14–16 Tg annually from mineral dust aerosols, but only a small percentage (approx. 3%) of it is soluble and, thus, bioavailable. In this work, we examine the effect of mineralogy, particle size, and surface area on iron solubility in pure mineral phases to simulate atmospheric processing of mineral dust aerosols during transport. Pure iron-bearing minerals common to Saharan dust were partitioned into four size fractions (10–2.5, 2.5–1, 1–0.5, and 0.5–0.25 µm) and extracted into moderately acidic (pH 4.3) and acidic (pH 1.7) leaching media to simulate mineral processing during atmospheric transport. Results show that, in general, pure iron-bearing clay materials present an iron solubility (% dissolved Fe/total Fe in the mineral) an order of magnitude higher than pure iron oxide minerals. The relative solubility of iron in clay particles does not depend on particle size for the ranges examined (0.25–10 μm), while iron in hematite and magnetite shows a trend of increasing solubility with decreasing particle size in the acidic leaching medium. Our results indicate that while mineralogy and aerosol pH have an effect on the solubilization of iron from simulated mineral dust particles, surface processes of the aerosol might also have a role in iron solubilization during transport. The surface area of clay minerals does not change significantly as a function of particle size (10–0.25 µm), while the surface area of iron oxides is strongly size dependent. Overall, these results show how mineralogy and particle size can influence iron solubility in atmospheric dust.
Aurelie R. Marcotte; Ariel D. Anbar; Brian J. Majestic; Pierre Herckes. Mineral Dust and Iron Solubility: Effects of Composition, Particle Size, and Surface Area. Atmosphere 2020, 11, 533 .
AMA StyleAurelie R. Marcotte, Ariel D. Anbar, Brian J. Majestic, Pierre Herckes. Mineral Dust and Iron Solubility: Effects of Composition, Particle Size, and Surface Area. Atmosphere. 2020; 11 (5):533.
Chicago/Turabian StyleAurelie R. Marcotte; Ariel D. Anbar; Brian J. Majestic; Pierre Herckes. 2020. "Mineral Dust and Iron Solubility: Effects of Composition, Particle Size, and Surface Area." Atmosphere 11, no. 5: 533.
Residual organics in cationic polymer contribute disproportionately to NDMA formation, but can be removed through polymer purification.
Ariel J. Atkinson; Natalia Fischer; Samantha Donovan; Justin Bartlett; Omar Alrehaili; Shahnawaz Sinha; Sunil Kommineni; Pierre Herckes; Paul Westerhoff. Purification and removal of the low molecular weight fraction of polyDADMAC reduces N-nitrosodimethylamine formation during water treatment. Environmental Science: Water Research & Technology 2020, 6, 2492 -2498.
AMA StyleAriel J. Atkinson, Natalia Fischer, Samantha Donovan, Justin Bartlett, Omar Alrehaili, Shahnawaz Sinha, Sunil Kommineni, Pierre Herckes, Paul Westerhoff. Purification and removal of the low molecular weight fraction of polyDADMAC reduces N-nitrosodimethylamine formation during water treatment. Environmental Science: Water Research & Technology. 2020; 6 (9):2492-2498.
Chicago/Turabian StyleAriel J. Atkinson; Natalia Fischer; Samantha Donovan; Justin Bartlett; Omar Alrehaili; Shahnawaz Sinha; Sunil Kommineni; Pierre Herckes; Paul Westerhoff. 2020. "Purification and removal of the low molecular weight fraction of polyDADMAC reduces N-nitrosodimethylamine formation during water treatment." Environmental Science: Water Research & Technology 6, no. 9: 2492-2498.
This study focused on nitrate leaching through soil during growth of romaine lettuce where 2-D graphite (CNPs) were combined with fertilizer and applied to soil to test the CNP effect on yield, nitrate leaching, and plant nutrient uptake.
Madelyn Pandorf; Leila Pourzahedi; Leanne M Gilbertson; Gregory V. Lowry; Pierre Herckes; Paul Westerhoff. Graphite nanoparticle addition to fertilizers reduces nitrate leaching in growth of lettuce (Lactuca sativa). Environmental Science: Nano 2019, 7, 127 -138.
AMA StyleMadelyn Pandorf, Leila Pourzahedi, Leanne M Gilbertson, Gregory V. Lowry, Pierre Herckes, Paul Westerhoff. Graphite nanoparticle addition to fertilizers reduces nitrate leaching in growth of lettuce (Lactuca sativa). Environmental Science: Nano. 2019; 7 (1):127-138.
Chicago/Turabian StyleMadelyn Pandorf; Leila Pourzahedi; Leanne M Gilbertson; Gregory V. Lowry; Pierre Herckes; Paul Westerhoff. 2019. "Graphite nanoparticle addition to fertilizers reduces nitrate leaching in growth of lettuce (Lactuca sativa)." Environmental Science: Nano 7, no. 1: 127-138.
Cookstoves emit many pollutants that are harmful to human health and the environment. However, most of the existing scientific literature focuses on fine particulate matter (PM2.5) and carbon monoxide (CO). We present an extensive dataset of speciated air pollution emissions from wood, charcoal, kerosene, and liquefied petroleum gas (LPG) cookstoves. One-hundred and twenty gas- and particle-phase constituents—including organic carbon, elemental carbon, ultrafine particles (10-100 nm), inorganic ions, carbohydrates, and volatile/semi-volatile organic compounds (e.g., alkanes, alkenes, alkynes, aromatics, carbonyls, and polycyclic aromatic hydrocarbons [PAHs])—were measured in the exhaust from 26 stove/fuel combinations. We find that improved biomass stoves tend to reduce PM2.5 emissions, however, certain design features (e.g., insulation or a fan) tend to increase relative levels of other co-emitted pollutants (e.g., elemental carbon, ultrafine particles, formaldehyde, or PAHs depending on stove type). In contrast, the pressurized kerosene and LPG stoves reduced all pollutants relative to a traditional three-stone fire (≥93% and ≥79%, respectively). Finally, we find that PM2.5 and CO are not strong predictors of co-emitted pollutants, which is problematic because these pollutants may not be indicators of other cookstove smoke constituents (such as formaldehyde and acetaldehyde) that may be emitted at concentrations that are harmful to human health.
Kelsey R. Bilsback; Jordyn Dahlke; Kristen M. Fedak; Nicholas Good; Arsineh Hecobian; Pierre Herckes; Christian L’Orange; John Mehaffy; Amy Sullivan; Jessica Tryner; Lizette Van Zyl; Ethan Walker; Yong Zhou; Jeffrey R. Pierce; Ander Wilson; Jennifer L. Peel; John Volckens. A Laboratory Assessment of 120 Air Pollutant Emissions from Biomass and Fossil Fuel Cookstoves. Environmental Science & Technology 2019, 53, 7114 -7125.
AMA StyleKelsey R. Bilsback, Jordyn Dahlke, Kristen M. Fedak, Nicholas Good, Arsineh Hecobian, Pierre Herckes, Christian L’Orange, John Mehaffy, Amy Sullivan, Jessica Tryner, Lizette Van Zyl, Ethan Walker, Yong Zhou, Jeffrey R. Pierce, Ander Wilson, Jennifer L. Peel, John Volckens. A Laboratory Assessment of 120 Air Pollutant Emissions from Biomass and Fossil Fuel Cookstoves. Environmental Science & Technology. 2019; 53 (12):7114-7125.
Chicago/Turabian StyleKelsey R. Bilsback; Jordyn Dahlke; Kristen M. Fedak; Nicholas Good; Arsineh Hecobian; Pierre Herckes; Christian L’Orange; John Mehaffy; Amy Sullivan; Jessica Tryner; Lizette Van Zyl; Ethan Walker; Yong Zhou; Jeffrey R. Pierce; Ander Wilson; Jennifer L. Peel; John Volckens. 2019. "A Laboratory Assessment of 120 Air Pollutant Emissions from Biomass and Fossil Fuel Cookstoves." Environmental Science & Technology 53, no. 12: 7114-7125.
Many analytical techniques have limited sensitivity to quantify multi-walled carbon nanotubes (MWCNTs) at environmentally relevant exposure concentrations in wastewaters. We found that trace metals (e.g., Y, Co, Fe) used in MWCNT synthesis correlated with MWCNT concentrations. Because of low background yttrium (Y) concentrations in wastewater, Y was used to track MWCNT removal by wastewater biomass. Transmission electron microscopy (TEM) imaging and dissolution studies indicated that the residual trace metals were strongly embedded within the MWCNTs. For our specific MWCNT, Y concentration in MWCNTs was 76 µg g−1, and single particle mode inductively coupled plasma mass spectrometry (spICP-MS) was shown viable to detect Y-associated MWCNTs. The detection limit of the specific MWCNTs was 0.82 µg L−1 using Y as a surrogate, compared with >100 µg L−1 for other techniques applied for MWCNT quantification in wastewater biomass. MWCNT removal at wastewater treatment plants (WWTPs) was assessed by dosing MWCNTs (100 µg L−1) in water containing a range of biomass concentrations obtained from wastewater return activated sludge (RAS) collected from a local WWTP. Using high volume to surface area reactors (to limit artifacts of MWCNT loss due to adsorption to vessel walls) and adding 5 g L−1 of total suspended solids (TSS) of RAS (3-h mixing) reduced the MWCNT concentrations from 100 µg L−1 to 2 µg L−1. The results provide an environmentally relevant insight into the fate of MWCNTs across their end of life cycle and aid in regulatory permits that require estimates of engineered nanomaterial removal at WWTPs upon accidental release into sewers from manufacturing facilities.
Justin Kidd; Yuqiang Bi; David Hanigan; Pierre Herckes; Paul Westerhoff. Yttrium Residues in MWCNT Enable Assessment of MWCNT Removal during Wastewater Treatment. Nanomaterials 2019, 9, 670 .
AMA StyleJustin Kidd, Yuqiang Bi, David Hanigan, Pierre Herckes, Paul Westerhoff. Yttrium Residues in MWCNT Enable Assessment of MWCNT Removal during Wastewater Treatment. Nanomaterials. 2019; 9 (5):670.
Chicago/Turabian StyleJustin Kidd; Yuqiang Bi; David Hanigan; Pierre Herckes; Paul Westerhoff. 2019. "Yttrium Residues in MWCNT Enable Assessment of MWCNT Removal during Wastewater Treatment." Nanomaterials 9, no. 5: 670.
A field study on fog chemistry and aqueous-phase processing of aerosol particles was conducted in Fresno, California’s San Joaquin Valley (SJV) during wintertime. Fog droplets were collected while interstitial submicron aerosol was characterized in real time using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS). The fog samples were later analyzed using HR-AMS, ion chromatography (IC), and total organic carbon analyzer (TOC). Compared to interstitial aerosols, dissolved solutes in fog waters were composed of higher fractions of ammonium, nitrate, sulfate, methanesulfonic acid, and oxygenated organic compounds, likely due to aqueous formation of secondary species as well as enhanced gas-to-particle partitioning of water-soluble gases under humid conditions. The low-volatility dissolved organic matter in fog water (F-OA) was moderately oxidized with an average oxygen-to-carbon (O/C) ratio of 0.42. The chemical composition of F-OA appeared to be overall similar to that of oxygenated organic component in interstitial aerosol (OOA) and the HR-AMS mass spectra of F-OA and OOA are highly similar (r2 > 0.95). However, there are also significant chemical differences as F-OA appeared to contain a larger fraction of carboxylic functional groups than OOA, indicating enhanced organic acid formation through aqueous-phase reactions. In addition, F-OA was composed of substantially more nitrogen-containing compounds, with an average N/C ratio ∼ 4 times that of OOA. Most strikingly was that the F-OA spectra showed substantial enhancements of the CxHyN2+ (x ≥ 0; y ≥ 0) ions, which were likely contributed by imidazole- and/or pyrazine-based compounds formed from the aqueous reactions of aldehydes with amino compounds. The results of this study demonstrated that aqueous reactions in atmospheric droplets can significantly modify aerosol composition and contribute to the formation of oxygenated and nitrogen-containing organic compounds in atmospheric aerosol particles. This finding is important for understanding aerosol’s effects on human health, air quality, and climate.
Hwajin Kim; Sonya Collier; Xinlei Ge; Jianzhong Xu; Yele Sun; Wenqing Jiang; Youliang Wang; Pierre Herckes; Qi Zhang. Chemical processing of water-soluble species and formation of secondary organic aerosol in fogs. Atmospheric Environment 2018, 200, 158 -166.
AMA StyleHwajin Kim, Sonya Collier, Xinlei Ge, Jianzhong Xu, Yele Sun, Wenqing Jiang, Youliang Wang, Pierre Herckes, Qi Zhang. Chemical processing of water-soluble species and formation of secondary organic aerosol in fogs. Atmospheric Environment. 2018; 200 ():158-166.
Chicago/Turabian StyleHwajin Kim; Sonya Collier; Xinlei Ge; Jianzhong Xu; Yele Sun; Wenqing Jiang; Youliang Wang; Pierre Herckes; Qi Zhang. 2018. "Chemical processing of water-soluble species and formation of secondary organic aerosol in fogs." Atmospheric Environment 200, no. : 158-166.
This study provides the feasibility of using a single-particle ICP-MS technique for convenient and routine monitoring of engineered nanomaterials in tap water.
Arjun K. Venkatesan; Blanca Rodriguez; Aurelie R. Marcotte; Xiangyu Bi; Jared Schoepf; James F. Ranville; Pierre Herckes; Paul Westerhoff. Using single-particle ICP-MS for monitoring metal-containing particles in tap water. Environmental Science: Water Research & Technology 2018, 4, 1923 -1932.
AMA StyleArjun K. Venkatesan, Blanca Rodriguez, Aurelie R. Marcotte, Xiangyu Bi, Jared Schoepf, James F. Ranville, Pierre Herckes, Paul Westerhoff. Using single-particle ICP-MS for monitoring metal-containing particles in tap water. Environmental Science: Water Research & Technology. 2018; 4 (12):1923-1932.
Chicago/Turabian StyleArjun K. Venkatesan; Blanca Rodriguez; Aurelie R. Marcotte; Xiangyu Bi; Jared Schoepf; James F. Ranville; Pierre Herckes; Paul Westerhoff. 2018. "Using single-particle ICP-MS for monitoring metal-containing particles in tap water." Environmental Science: Water Research & Technology 4, no. 12: 1923-1932.
Natural nanoparticles (NNPs) in rivers, lakes, oceans and ground water predate humans, but engineered nanoparticles (ENPs) are emerging as potential pollutants due to increasing regulatory and public perception concerns. This Review contrasts the sources, composition and potential occurrence of NNPs (for example, two-dimensional clays, multifunctional viruses and metal oxides) and ENPs in surface water, after centralized drinking water treatment, and in tap water. While analytical detection challenges exist, ENPs are currently orders of magnitude less common than NNPs in waters that flow into drinking water treatment plants. Because such plants are designed to remove small-sized NNPs, they are also very good at removing ENPs. Consequently, ENP concentrations in tap water are extremely low and pose low risk during ingestion. However, after leaving drinking water treatment plants, corrosion by-products released from distribution pipes or in-home premise plumbing can release incidental nanoparticles into tap water. The occurrence and toxicity of incidental nanoparticles, rather than ENPs, should therefore be the focus of future research.
Paul Westerhoff; Ariel Atkinson; John Fortner; Michael S. Wong; Julie Zimmerman; Jorge Gardea-Torresdey; James Ranville; Pierre Herckes. Low risk posed by engineered and incidental nanoparticles in drinking water. Nature Nanotechnology 2018, 13, 661 -669.
AMA StylePaul Westerhoff, Ariel Atkinson, John Fortner, Michael S. Wong, Julie Zimmerman, Jorge Gardea-Torresdey, James Ranville, Pierre Herckes. Low risk posed by engineered and incidental nanoparticles in drinking water. Nature Nanotechnology. 2018; 13 (8):661-669.
Chicago/Turabian StylePaul Westerhoff; Ariel Atkinson; John Fortner; Michael S. Wong; Julie Zimmerman; Jorge Gardea-Torresdey; James Ranville; Pierre Herckes. 2018. "Low risk posed by engineered and incidental nanoparticles in drinking water." Nature Nanotechnology 13, no. 8: 661-669.
Phosphorus (P) is an important and often limiting element in terrestrial and aquatic ecosystem. A lack of understanding of its distribution and structures in the environment limits the design of effective P mitigation and recovery approaches. Here we developed a robust method employing size exclusion chromatography (SEC) coupled to an ICP-MS to determine the molecular weight (MW) distribution of P in environmental samples. The most abundant fraction of P varied widely in different environmental samples: (i) orthophosphate was the dominant fraction (93-100%) in one lake, two aerosols and DOC isolate samples, (ii) species of 400-600 Da range were abundant (74-100%) in two surface waters, and (iii) species of 150-350 Da range were abundant in wastewater effluents. SEC-DOC of the aqueous samples using a similar SEC column showed overlapping peaks for the 400-600 Da species in two surface waters, and for >20 kDa species in the effluents, suggesting that these fractions are likely associated with organic matter. The MW resolution and performance of SEC-ICP-MS agreed well with the time integrated results obtained using conventional ultrafiltration method. Results show that SEC in combination with ICP-MS and DOC has the potential to be a powerful and easy-to-use method in identifying unknown fractions of P in the environment.
Arjun K. Venkatesan; Wenhui Gan; Harsh Ashani; Pierre Herckes; Paul Westerhoff. Size exclusion chromatography with online ICP-MS enables molecular weight fractionation of dissolved phosphorus species in water samples. Water Research 2018, 133, 264 -271.
AMA StyleArjun K. Venkatesan, Wenhui Gan, Harsh Ashani, Pierre Herckes, Paul Westerhoff. Size exclusion chromatography with online ICP-MS enables molecular weight fractionation of dissolved phosphorus species in water samples. Water Research. 2018; 133 ():264-271.
Chicago/Turabian StyleArjun K. Venkatesan; Wenhui Gan; Harsh Ashani; Pierre Herckes; Paul Westerhoff. 2018. "Size exclusion chromatography with online ICP-MS enables molecular weight fractionation of dissolved phosphorus species in water samples." Water Research 133, no. : 264-271.
2-Step extraction/detection method was developed for quantification of carbonaceous nanomaterials (CNMs) in polymer composites using Programmed Thermal Analysis (PTA).
Takayuki Nosaka; Ronald Lankone; Yuqiang Bi; D. H. Fairbrother; Paul Westerhoff; Pierre Herckes; Howard Fairbrother. Quantification of carbon nanotubes in polymer composites. Analytical Methods 2018, 10, 1032 -1037.
AMA StyleTakayuki Nosaka, Ronald Lankone, Yuqiang Bi, D. H. Fairbrother, Paul Westerhoff, Pierre Herckes, Howard Fairbrother. Quantification of carbon nanotubes in polymer composites. Analytical Methods. 2018; 10 (9):1032-1037.
Chicago/Turabian StyleTakayuki Nosaka; Ronald Lankone; Yuqiang Bi; D. H. Fairbrother; Paul Westerhoff; Pierre Herckes; Howard Fairbrother. 2018. "Quantification of carbon nanotubes in polymer composites." Analytical Methods 10, no. 9: 1032-1037.
Heather O’Neal Tugaoen; Pierre Herckes; Kiril Hristovski; Paul Westerhoff. Influence of ultraviolet wavelengths on kinetics and selectivity for N-gases during TiO2 photocatalytic reduction of nitrate. Applied Catalysis B: Environmental 2018, 220, 597 -606.
AMA StyleHeather O’Neal Tugaoen, Pierre Herckes, Kiril Hristovski, Paul Westerhoff. Influence of ultraviolet wavelengths on kinetics and selectivity for N-gases during TiO2 photocatalytic reduction of nitrate. Applied Catalysis B: Environmental. 2018; 220 ():597-606.
Chicago/Turabian StyleHeather O’Neal Tugaoen; Pierre Herckes; Kiril Hristovski; Paul Westerhoff. 2018. "Influence of ultraviolet wavelengths on kinetics and selectivity for N-gases during TiO2 photocatalytic reduction of nitrate." Applied Catalysis B: Environmental 220, no. : 597-606.
Single particle inductively coupled plasma mass spectrometry (spICP-MS) was used to detect Ti-containing particles in heavily-used bathing areas of a river (Salt River) and five swimming pools. Ti-containing particle concentrations in swimming pools ranged from 2.8 × 103 to 4.4 × 103 particles/mL and were an order of magnitude lower than those detected in the Salt River. Measurements from the Salt River showed an 80% increase in Ti-containing particle concentration over baseline concentration during peak recreational activity (at 16:00 h) in the river. Cloud point extraction followed by transmission electron microscopy with energy dispersive X-ray analysis confirmed presence of aggregated TiO2 particles in river samples, showing morphological similarity to particles present in an over-the-counter sunscreen product. The maximum particle mass concentration detected in a sample from the Salt River (659 ng/L) is only slightly lower than the predicted no effect concentration for TiO2 to aquatic organisms (< 1 μg/L).
Arjun K. Venkatesan; Robert B. Reed; SungYun Lee; Xiangyu Bi; David Hanigan; Yu Yang; James F. Ranville; Pierre Herckes; Paul Westerhoff. Detection and Sizing of Ti-Containing Particles in Recreational Waters Using Single Particle ICP-MS. Bulletin of Environmental Contamination and Toxicology 2017, 100, 120 -126.
AMA StyleArjun K. Venkatesan, Robert B. Reed, SungYun Lee, Xiangyu Bi, David Hanigan, Yu Yang, James F. Ranville, Pierre Herckes, Paul Westerhoff. Detection and Sizing of Ti-Containing Particles in Recreational Waters Using Single Particle ICP-MS. Bulletin of Environmental Contamination and Toxicology. 2017; 100 (1):120-126.
Chicago/Turabian StyleArjun K. Venkatesan; Robert B. Reed; SungYun Lee; Xiangyu Bi; David Hanigan; Yu Yang; James F. Ranville; Pierre Herckes; Paul Westerhoff. 2017. "Detection and Sizing of Ti-Containing Particles in Recreational Waters Using Single Particle ICP-MS." Bulletin of Environmental Contamination and Toxicology 100, no. 1: 120-126.
Engineered nanomaterials (ENM) have diverse applications in consumer products, but few studies weigh the improved product performance resulting from the inclusion of an ENM against the unintended consequences of released ENM. Engineered nanomaterials (ENM) have diverse applications in consumer products, but few studies weigh the improved product performance resulting from the inclusion of an ENM against the unintended consequences of released ENM. We developed and applied a framework to test a commercial floor coating that contains TiO 2 nanoparticles in a silicate/siliconate matrix for both efficacy and exposure risk. Extracted TiO 2 nanoparticles from the product were first characterized for particle size, morphology, mass concentration, and surface chemical composition prior to floor tile application. Porcelain tiles were coated with three TiO 2 concentrations to understand the effect of TiO 2 content on coating performance with respect to antimicrobial properties, abrasion resistance, and hydrophobicity. Coating porcelain tiles with the commercial product did not significantly enhance antimicrobial activity or scratch resistance compared to controls without TiO 2 nanoparticles. Particles released during accelerated abrasion were collected and analyzed by scanning electron microscopy (SEM) to inform exposure studies. During the abrasion test that simulated product use phase, TiO 2 nanoparticles clusters were effectively removed from tile surfaces and embedded in a micron-sized silicate matrix. Reactive oxygen species (ROS) generated in water by photocatalytic reactions using TiO 2 from the coating were an order of magnitude lower than by a TiO 2 nanoparticle standard. While the overall exposure risk to TiO 2 nanoparticles released from floor coatings is low, we did not observe increased efficacy from adding TiO 2 to the coating formulation. Product developers and policy makers may use the framework developed in this study to systematically assess the efficacy and product safety across a product's life cycle.
Yuqiang Bi; Tatiana Zaikova; Jared Schoepf; Pierre Herckes; James E. Hutchison; Paul Westerhoff. The efficacy and environmental implications of engineered TiO 2 nanoparticles in a commercial floor coating. Environmental Science: Nano 2017, 4, 2030 -2042.
AMA StyleYuqiang Bi, Tatiana Zaikova, Jared Schoepf, Pierre Herckes, James E. Hutchison, Paul Westerhoff. The efficacy and environmental implications of engineered TiO 2 nanoparticles in a commercial floor coating. Environmental Science: Nano. 2017; 4 (10):2030-2042.
Chicago/Turabian StyleYuqiang Bi; Tatiana Zaikova; Jared Schoepf; Pierre Herckes; James E. Hutchison; Paul Westerhoff. 2017. "The efficacy and environmental implications of engineered TiO 2 nanoparticles in a commercial floor coating." Environmental Science: Nano 4, no. 10: 2030-2042.