1
|
Hao W, Gao B, Liang B, Chen J, Dong L, Wang Z, Tian M. Distinct seasonal variability of source-dependent health risks from PM 2.5-bound PAHs and related derivatives in a megacity, southwest China: Implications for the significance of secondary formation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 885:163742. [PMID: 37116800 DOI: 10.1016/j.scitotenv.2023.163742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/10/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023]
Abstract
In contrast to polycyclic aromatic hydrocarbons (PAHs) which have been regularly monitored, the source-dependent health risk of their derivatives in ambient environment has not been well understood, especially regarding seasonal variability. In this study, oxygenated and nitrated PAHs (OPAHs and NPAHs) in PM2.5 samples from different seasons in urban Chongqing were analyzed and compared with PAHs from a human health perspective. Benzo[a]pyrene equivalent concentrations (BaPeq) were annually averaged at 6.13 ± 8.97 ng/m3 (n = 118) in the present study, with highest levels in winter followed by spring, autumn, and summer. The BaPeq values of OPAHs were higher than PAHs in spring and summer with seasonal averaged value up to 3.7 times of that for PAHs, manifesting significant underestimation of the health impact if only PAHs were considered. Incremental lifetime cancer risk (ILCR) model results suggested that the potential cancer risks were accumulated mostly from inhalation exposure during infancy and adulthood. Furthermore, in comparison with PAHs, OPAHs, mainly 6H-Benzo[c,d]pyren-6-one, had significant contribution to cancer risks (annually averaged at 58.3 %). Source-dependent cancer risks based on positive matrix factorization model denoted secondary formed PAH derivatives as a critical contributor to cancer risk, particularly in spring and summer (attributed to about 61 % of ILCR). The enhanced secondary formation of PAH derivatives during spring and summer was partially justified by diagnostic ratios and further analysis revealed that higher temperature, higher O3 level, and lower relative humidity besides stronger solar intensity during these two seasons as the most likely causes of this seasonal variation. Results in this study emphasizes that more knowledge on the formation and toxicity of OPAHs is imperative, especially in the context of complex PM2.5-ozone pollution in China.
Collapse
Affiliation(s)
- Weiwei Hao
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Bo Gao
- Guangdong Provincial Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510535, China
| | - Bo Liang
- Materials Quality Supervision & Inspection Research Center, Chongqing Academy of Metrology and Quality Inspection, Chongqing 401123, China
| | - Jing Chen
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Lingchi Dong
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Ziqian Wang
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Mi Tian
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China; Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
| |
Collapse
|
2
|
Rodríguez-Córdoba W, Gutiérrez-Arzaluz L, Cortés-Guzmán F, Peon J. Excited state dynamics and photochemistry of nitroaromatic compounds. Chem Commun (Camb) 2021; 57:12218-12235. [PMID: 34735557 DOI: 10.1039/d1cc04999b] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nitrated aromatic molecules have unique photoinduced channels. Due to the presence of oxygen-centered non-bonding orbitals, they can undergo sub-picosecond intersystem crossing showing one of the strongest couplings between the singlet and triplet manifolds among organic molecules. Several nitroaromatic compounds also have a distinctive nitric oxide photodissociation channel which occurs through a complex sequence of atom rearrangements and state changes. These remarkable processes have stimulated the attention of several research groups over the last few years who have applied modern femtosecond spectroscopies and new computational methods to these topics. Nitroaromatic molecules also have demonstrated their value as case-studies, where they can serve to understand the influence of torsional motions between the nitro substituent and the aromatic system in the conversions between states. In this contribution we highlight several of the recent results in this area. Due to the importance of the atmospheric photochemistry of nitrated compounds and their accumulating applications as nitric oxide release agents, continued research about the effects of the different state orderings, substitution patterns, and solvent effects is central to the development of future applications and for a better understanding of their environmental pathways. From this analysis, several pending issues are highlighted, which include the nature of the dominant singlet state involved in intersystem crossing, the role of the formation of charge-transfer states, the yield of the internal conversion channel to the electronic ground state, and a more generalized understanding of the sequence of steps which lead to nitric oxide dissociation.
Collapse
Affiliation(s)
- William Rodríguez-Córdoba
- Facultad de ciencias, Escuela de Física, Laboratorio de Fotónica y Optoelectrónica, Universidad Nacional de Colombia - Sede Medellín, Calle 59 A No. 63-20, A.A. 3840, Medellín, Colombia.
| | - Luis Gutiérrez-Arzaluz
- Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
| | - Fernando Cortés-Guzmán
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 D.F., Mexico.
| | - Jorge Peon
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 D.F., Mexico.
| |
Collapse
|
3
|
Kang Q, Bao S, Chen B. Phototransformation of three polychlorinated naphthalenes on surface of atmospheric particulate matter. JOURNAL OF HAZARDOUS MATERIALS 2021; 409:124895. [PMID: 33418299 DOI: 10.1016/j.jhazmat.2020.124895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
Polychlorinated naphthalenes (PCNs) are a new class of persistent organic pollutants. Photoconversion is an important pathway for their transformation in the environment. In this work, silica gel was used to simulate atmospheric mineral particles, and the photochemical reaction of three PCNs 1-chloronaphthalene (CN-1), 2-chloronaphthalene (CN-2) and 2,3-dichloronaphthalene (CN-10)) on silica gel surface was studied under the irradiation of high-pressure mercury lamp, the phototransformation intermediates and pathways of PCNs were investigated, effects of reactive oxygen species (ROS, ·OH, 1O2 and O2-·) were proved by free radical scavenging method and the effects of co-existing components (water, inorganic ions and fulvic acid) were examined. The results showed that all the three PCNs could be photochemical degraded on silica gel surface. The order of the apparent rate constants was CN-2 ≈ CN-1 > CN-10. ROS accelerated the photochemical reaction. The three PCNs didn't produce completely identical photoproducts, but all underwent a series of reactions such as reductive dechlorination, hydroxylation, oxidation, decarboxylation and ring opening. In addition, for the photoconversion of CN-1, the presence of water, NO3- or fulvic acid all promoted the photochemical transformation, while the presence of Cu2+ had an inhibitory effect.
Collapse
Affiliation(s)
- Qiao Kang
- Northern Region Persistent Organic Pollution Control (NRPOP) Laboratory, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL A1B 3X5, Canada
| | - Siqi Bao
- College of New Energy and Environment, Jilin University, Changchun 130012, China; School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, China.
| | - Bing Chen
- Northern Region Persistent Organic Pollution Control (NRPOP) Laboratory, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL A1B 3X5, Canada.
| |
Collapse
|
4
|
Sun H, Wang M, Nan Y, Han M, Lu H. The Kinetics and Mechanisms for Photodegradation of Nitrated Polycyclic Aromatic Hydrocarbons on Lettuce Leaf Surfaces: An In Vivo Study. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:8452-8458. [PMID: 31294967 DOI: 10.1021/acs.jafc.9b02326] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Insights into the environmental fates of nitrated polycyclic aromatic hydrocarbons (NPAHs) in edible vegetables are of great significance for better evaluating human exposure to NPAHs through the dietary pathway. In this work, a fluorescence quenching method using graphene quantum dots as a fluorescent probe was first applied for the in vivo determination of 9-nitroanthracene (9-NAnt) and 1-nitropyrene (1-NPyr) adsorbed on the leaf surfaces of living lettuce (Lactuca sativa L.) seedlings. Moreover, the photolysis kinetics and mechanisms of the two adsorbed NPAHs were discussed. The photodegradation kinetics followed the pseudo-first-order equation, and the photodegradation half-life of 1-NPyr (7.4 ± 0.2 h) was greater than that of 9-NAnt (2.3 ± 0.1 h). Anthraquinone and pyrenediones were identified to be the main photolytic products of 9-NAnt and 1-NPyr, respectively. Intramolecular rearrangement was the most reasonable mechanism for the NPAH photolysis. The photolysis-driven degradation exhibited a key role in scavenging NPAHs from the vegetable leaf, indicating the reduction of NPAH transportation in the food chain.
Collapse
Affiliation(s)
- Haifeng Sun
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
- Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province , Taiyuan 030031 , P. R. China
| | - Meng Wang
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
| | - Yanli Nan
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
| | - Ming Han
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
| | - Haoliang Lu
- Key Laboratory of Ministry of Coastal and Wetland Ecosystem , Xiamen University , Xiamen 361102 , P. R. China
| |
Collapse
|
5
|
Brister MM, Piñero-Santiago LE, Morel M, Arce R, Crespo-Hernández CE. Photochemical Relaxation Pathways in Dinitropyrene Isomer Pollutants. J Phys Chem A 2017; 121:8197-8206. [PMID: 28984454 DOI: 10.1021/acs.jpca.7b04769] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Dinitropyrenes are polycyclic aromatic pollutants prevalent in the environment. While their transformations by sunlight in the environment have been documented, the effect that the nitro-group substitution pattern has on the relaxation pathways has not been extensively studied. In this contribution, the steady-state and femtosecond-to-microsecond excited-state dynamics of 1,3-dinitropyrene and 1,8-dinitropyrene isomers are investigated upon visible light excitation at 425 nm and compared with those recently reported for the 1,6-dinitropyrene isomer. The experimental results are complemented with ground- and excited-state density functional calculations. It is shown that excitation at 425 nm results in the ultrafast branching of the excited-state population in the S1 state to populate the triplet state in ca. 90% yield and to form a nitropyrenoxy radical in less than 10% yield. In addition, the position of the NO2 group does not affect significantly the excited-state relaxation mechanism, while it does influence the absorption and fluorescence spectra, the fluorescence, triplet, singlet oxygen, and photodegradation yields, as well as the relative yield of radical formation. Radical formation is implicated in the photodegradation of these pollutants, while in the presence of hydrogen donors, direct reactions from the triplet state are also observed.
Collapse
Affiliation(s)
- Matthew M Brister
- Department of Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Luis E Piñero-Santiago
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - María Morel
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - Rafael Arce
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - Carlos E Crespo-Hernández
- Department of Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| |
Collapse
|
6
|
Brister MM, Piñero-Santiago LE, Morel M, Arce R, Crespo-Hernández CE. The Photochemical Branching Ratio in 1,6-Dinitropyrene Depends on the Excitation Energy. J Phys Chem Lett 2016; 7:5086-5092. [PMID: 27973879 DOI: 10.1021/acs.jpclett.6b02549] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nitropolycyclic aromatic hydrocarbons constitute one of the most disconcerting classes of pollutants. Photochemical degradation is thought to be a primary mode of their natural removal from the environment, but the microscopic mechanism leading to product formation as a function of excitation wavelength is poorly understood. In this Letter, it is revealed that excitation of 1,6-dinitropyrene with 425, 415, or 340 nm radiation leads to an increasing amount of radical production through photodissociation at the expense of triplet-state population-the two primary reaction pathways in this class of pollutants. Radical formation requires overcoming an energy barrier in the excited singlet manifold. This activation energy explains the large fraction of the initial singlet-state population that intersystem crosses to a doorway triplet state, instead of leading overwhelmingly to photodissociation. The unforeseen excitation wavelength dependence of this branching process is expected to regulate the photochemistry of 1,6-dinitropyrene and possibly of other nitroaromatic pollutants in the environment.
Collapse
Affiliation(s)
- Matthew M Brister
- Department of Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Luis E Piñero-Santiago
- Department of Chemistry, University of Puerto Rico at Humacao , Humacao Campus, Humacao, Puerto Rico 00792
| | - María Morel
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931
| | - Rafael Arce
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931
| | - Carlos E Crespo-Hernández
- Department of Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| |
Collapse
|