Heterogeneous OH Oxidation, Shielding Effects, and Implications for the Atmospheric Fate of Terbuthylazine and Other Pesticides

Socorro, Joanna; Lakey, Pascale S. J.; Han, Lei; Berkemeier, Thomas; Lammel, Gerhard; Zetzsch, Cornelius; Pöschl, Ulrich; Shiraiwa, Manabu

doi:10.1021/acs.est.7b04307

Cited by 25 publications

(19 citation statements)

References 64 publications

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“…We are not aware of previous reports of unsaturated surfactants being protected from attack by atmospheric oxidants at the air-water interface via chain-chain interactions induced by ions in the subphase. This is a particularly interesting finding, since it is very likely that in atmospheric conditions a range of ions will be present in the aerosol droplets; therefore this process may provide an alternative explanation [22,51,52] for extended atmospheric residence times that have been found for reactive species and may have important health implications [53].…”

Section: Discussionmentioning

confidence: 86%

Night-Time Oxidation of a Monolayer Model for the Air–Water Interface of Marine Aerosols—A Study by Simultaneous Neutron Reflectometry and in Situ Infra-Red Reflection Absorption Spectroscopy (IRRAS)

et al. 2018

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This paper describes experiments on the ageing of a monolayer model for the air–water interface of marine aerosols composed of a typical glycolipid, galactocerebroside (GCB). Lipopolysaccharides have been observed in marine aerosols, and GCB is used as a proxy for these more complex lipopolysaccharides. GCB monolayers are investigated as pure films, as mixed films with palmitic acid, which is abundant in marine aerosols and forms a stable attractively mixed film with GCB, particularly with divalent salts present in the subphase, and as mixed films with palmitoleic acid, an unsaturated analogue of palmitic acid. Such mixed films are more realistic models of atmospheric aerosols than simpler single-component systems. Neutron reflectometry (NR) has been combined in situ with Fourier transform infra-red reflection absorption spectroscopy (IRRAS) in a pioneering analysis and reaction setup designed by us specifically to study mixed organic monolayers at the air–water interface. The two techniques in combination allow for more sophisticated observation of multi-component monolayers than has previously been possible. The structure at the air–water interface was also investigated by complementary Brewster angle microscopy (BAM). This study looks specifically at the oxidation of the organic films by nitrate radicals (NO3•), the key atmospheric oxidant present at night. We conclude that NO3• oxidation cannot fully remove a cerebroside monolayer from the surface on atmospherically relevant timescales, leaving its saturated tail at the interface. This is true for pure and salt water subphases, as well as for single- and two-component films. The behaviour of the unsaturated tail section of the molecule is more variable and is affected by interactions with co-deposited species. Most surprisingly, we found that the presence of CaCl2 in the subphase extends the lifetime of the unsaturated tail substantially—a new explanation for longer residence times of materials in the atmosphere compared to lifetimes based on laboratory studies of simplified model systems. It is thus likely that aerosols produced from the sea-surface microlayer at night will remain covered in surfactant molecules on atmospherically relevant timescales with impact on the droplet’s surface tension and on the transport of chemical species across the air–water interface.

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Section: Discussionmentioning

confidence: 86%

Night-Time Oxidation of a Monolayer Model for the Air–Water Interface of Marine Aerosols—A Study by Simultaneous Neutron Reflectometry and in Situ Infra-Red Reflection Absorption Spectroscopy (IRRAS)

et al. 2018

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“…Kinetic constants were two orders of magnitude higher on hydrophobic silica (Pflieger et al, 2013) than on hydrophilic silica (Palm et al, 1997). The difference could be attributed to mass transport and shielding effect induced by different experimental techniques and conditions (Socorro et al, 2017).…”

Section: Comparison With Other Studiesmentioning

confidence: 91%

Heterogeneous degradation of pesticides by OH radicals in the atmosphere: Influence of humidity and particle type on the kinetics

Mattei

Wortham

Quivet

2019

Science of The Total Environment

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Pesticides can be adsorbed on the surface of atmospheric aerosol, depending on their physicochemical properties. They can be degraded by atmospheric oxidants such as OH radicals but the influence of some environmental parameters on the degradation kinetics, especially relative humidity and particle surface type, is not well understood. Heterogeneous degradation by OH radicals of eight commonly used pesticides (i.e., difenoconazole, tetraconazole, cyprodinil, fipronil, oxadiazon, pendimethalin, deltamethrin, and permethrin) adsorbed on hydrophobic and hydrophilic silicas at a relative humidity ranging from 0% to 70% was studied. Under experimental conditions, only cyprodinil, deltamethrin, permethrin, and pendimethalin were degraded by OH radical in atmospheric relevant concentration. Second-order kinetic constants calculated for the pesticides degraded by OH radicals ranged from (1.93 ± 0.61) x 10-13 cm 3 molecule-1 s-1 (permethrin, hydrophobic silica, 30% RH) to (4.08 ± 0.27) x 10-12 cm 3 molecule-1 s-1 (pendimethalin, hydrophilic silica, 0% RH). Results obtained can contribute to improve the understanding of the atmospheric fate of pesticides and other semi-volatile organic compounds in the particulate phase and they highlight the importance of taking humidity and particle type into account for the determination of pesticides atmospheric half-lives.

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“…Of importance, Sauret et al (2008) outlined that pesticides recently placed on the market are less volatile than the older ones (e.g., organochlorine compounds) and are mainly associated to the atmospheric particulate phase. Atmospheric sinks of pesticides include wet or dry deposition (Majewski et al, 2014), and direct (Borras et al, 2017) or indirect (Socorro et al, 2017) photochemical degradation.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous atmospheric degradation of pesticides by ozone: Influence of relative humidity and particle type

Mattei

Wortham

Quivet

2018

Science of The Total Environment

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In the atmosphere pesticides can be adsorbed on the surface of particles, depending on their physico-chemical properties. They can react with atmospheric oxidants such as ozone but parameters influencing the degradation kinetics are not clear enough. In this study the heterogeneous ozonolysis of eight commonly used pesticides (i.e., difenoconazole, tetraconazole, cyprodinil, fipronil, oxadiazon, pendimethalin, deltamethrin, and permethrin) adsorbed on hydrophobic and hydrophilic silicas, and Arizona dust at relative humidity ranging from 0% to 80% was investigated. Under experimental conditions, only cyprodinil, deltamethrin, permethrin and pendimethalin were degraded by ozone. Second-order kinetic constants calculated for the pesticides degraded by ozone ranged from (4.7 ± 0.4) × 10 cm molecule s (pendimethalin, hydrophobic silica, 55% RH) to (2.3 ± 0.4) × 10 cm molecule s (cyprodinil, Arizona dust, 0% RH). Results obtained can contribute to a better understanding of the atmospheric fate of pesticides in the particulate phase and show the importance of taking humidity and particle type into account for the determination of pesticides atmospheric half-lives.

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Heterogeneous OH Oxidation, Shielding Effects, and Implications for the Atmospheric Fate of Terbuthylazine and Other Pesticides

Cited by 25 publications

References 64 publications

Night-Time Oxidation of a Monolayer Model for the Air–Water Interface of Marine Aerosols—A Study by Simultaneous Neutron Reflectometry and in Situ Infra-Red Reflection Absorption Spectroscopy (IRRAS)

Night-Time Oxidation of a Monolayer Model for the Air–Water Interface of Marine Aerosols—A Study by Simultaneous Neutron Reflectometry and in Situ Infra-Red Reflection Absorption Spectroscopy (IRRAS)

Heterogeneous degradation of pesticides by OH radicals in the atmosphere: Influence of humidity and particle type on the kinetics

Heterogeneous atmospheric degradation of pesticides by ozone: Influence of relative humidity and particle type

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