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Milstead RP, Berg SM, Kelly BM, Knellwolf CD, Larson CJ, Wammer KH, Remucal CK. Limitations of conventional approaches to identify photochemically produced reactive intermediates involved in contaminant indirect photodegradation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:1694-1707. [PMID: 37728410 PMCID: PMC10591881 DOI: 10.1039/d3em00304c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Dissolved organic matter (DOM) mediated indirect photodegradation can play an important role in the degradation of aquatic contaminants. Predicting the rate of this process requires knowledge of the photochemically produced reactive intermediates (PPRI) that react with the compound of interest, as well as the ability of individual DOM samples to produce PPRI. Key PPRI are typically identified using quencher studies, yet this approach often leads to results that are difficult to interpret. In this work, we analyze the indirect photodegradation of atorvastatin, carbamazepine, sulfadiazine, and benzotriazole using a diverse set of 48 waters from natural and engineered aquatic systems. We use this large data set to evaluate relationships between PPRI formation and indirect photodegradation rate constants, which are directly compared to results using standard quenching experiments. These data demonstrate that triplet state DOM (3DOM) and singlet oxygen (1O2) are critical PPRI for atorvastatin, carbamazepine, and sulfadiazine, while hydroxyl radical (˙OH) contributes to the indirect photodegradation of benzotriazole. We caution against relying on quenching studies because quenching of 3DOM limits the formation of 1O2 and all studied quenchers react with ˙OH. Furthermore, we show that DOM composition directly influences indirect photodegradation and that low molecular weight, microbial-like DOM is positively correlated with the indirect photodegradation rates of carbamazepine, sulfadiazine, and benzotriazole.
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Affiliation(s)
- Reid P Milstead
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park St., Madison, Wisconsin 53706, USA.
| | - Stephanie M Berg
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park St., Madison, Wisconsin 53706, USA.
| | - Bella M Kelly
- Department of Chemistry, University of St. Thomas, St. Paul, Minnesota 55105, USA
| | | | - Cooper J Larson
- Department of Chemistry, University of St. Thomas, St. Paul, Minnesota 55105, USA
| | - Kristine H Wammer
- Department of Chemistry, University of St. Thomas, St. Paul, Minnesota 55105, USA
| | - Christina K Remucal
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park St., Madison, Wisconsin 53706, USA.
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, USA
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Maizel AC, Remucal CK. Molecular Composition and Photochemical Reactivity of Size-Fractionated Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2113-2123. [PMID: 28121132 PMCID: PMC5889133 DOI: 10.1021/acs.est.6b05140] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The photochemical production of reactive species, such as triplet dissolved organic matter (3DOM) and singlet oxygen (1O2), contributes to the degradation of aquatic contaminants and is related to an array of DOM structural characteristics, notably molecular weight. In order to relate DOM molecular weight, optical properties, and reactive species production, Suwannee River (SRFA) and Pony Lake fulvic acid (PLFA) isolates are fractionated by sequential ultrafiltration, and the resultant fractions are evaluated in terms of molecular composition and photochemical reactivity. UV-visible measurements of aromaticity increase with molecular weight in both fulvic acids, while PLFA molecular weight fractions are shown to be structurally similar by Fourier-transform ion cyclotron resonance mass spectrometry. In addition, Bray-Curtis dissimilarity analysis of formulas identified in the isolates and their size fractions reveal that SRFA and PLFA have distinct molecular compositions. Quantum yields of 3DOM, measured by electron and energy transfer probes, and 1O2 decreased with molecular weight. Decreasing [3DOM]ss with molecular weight is shown to derive from elevated quenching in high molecular weight fractions, rather than increased 3DOM formation. This work has implications for the photochemistry of waters undergoing natural or engineered treatment processes that alter DOM molecular weight, such as photooxidation and biological degradation.
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Affiliation(s)
- Andrew C. Maizel
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - Christina K. Remucal
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
- Environmental Chemistry and Technology Program, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
- Corresponding Author: ; telephone: (608) 262-1820; fax: (608) 262-0454; Twitter: @remucal
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Yin Y, Shen M, Zhou X, Yu S, Chao J, Liu J, Jiang G. Photoreduction and stabilization capability of molecular weight fractionated natural organic matter in transformation of silver ion to metallic nanoparticle. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9366-9373. [PMID: 25050868 DOI: 10.1021/es502025e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Photoinduced reduction of silver ion (Ag(+)) to silver nanoparticles (AgNPs) by dissolved organic matter (DOM) plays a crucial role in the transformation and transport of engineered AgNPs and Ag(+) in aquatic environments. DOM is a mixture of natural polymers with wide molecular weight (MW) distribution, and the roles of specific components of DOM in the photoreduction of Ag(+) to AgNPs are still not understood. In this study, MW fractionated natural organic matter (Mf-NOM) were investigated for their roles on the photoreduction process and stabilization of the formed AgNPs. This photoinduced reduction process depends highly on pH, concentration of Ag(+) and NOM, light quality, and the MW of Mf-NOM. Monochromatic radiation and light attenuation correction suggested that the difference of Mf-NOM on reduction was mainly ascribed to the differential light attenuation of Mf-NOM rather than the "real" reductive ability. More importantly, compared with low MW fractions, the high MW Mf-NOMs exhibit drastically higher capability in stabilizing the photosynthesized AgNPs against Ca(2+)-induced aggregation. This finding is important for a better understanding of the differential roles of Mf-NOM in the transformation and transport of Ag(+) and engineered AgNPs in DOM-rich surface water.
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Affiliation(s)
- Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
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Remucal CK. The role of indirect photochemical degradation in the environmental fate of pesticides: a review. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:628-53. [PMID: 24419250 DOI: 10.1039/c3em00549f] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Photochemical degradation contributes to the environmental fate of many pesticides in surface waters. A better understanding of the role of direct and indirect photochemical degradation of pesticides is necessary in order to predict their environmental fate and persistence. This review includes all major pesticide classes and focuses on the importance of dissolved organic matter (DOM) as a sensitizer in indirect photodegradation within aquatic systems. Photochemical studies conducted under environmentally relevant conditions (i.e., aqueous solutions with irradiation wavelengths >290 nm) are included. Comparisons are made between observed photodegradation rates in pure or buffered water and in water containing DOM to assess the extent of pesticide susceptibility to DOM-sensitized indirect photolysis. When data is available, the role of specific reactive species in indirect photodegradation is described. While it is possible to assess the relative importance of direct and indirect photodegradation on a pesticide-by-pesticide basis in many cases, it is often difficult to make generalizations based on compound class. Knowledge gaps and inconstancies in the current body of literature are discussed and areas that require additional research are described.
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Affiliation(s)
- Christina K Remucal
- University of Wisconsin-Madison, Department of Civil and Environmental Engineering, 660 N. Park St., Madison, WI, USA.
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Chen SY, Huang SW, Chiang PN, Liu JC, Kuan WH, Huang JH, Hung JT, Tzou YM, Chen CC, Wang MK. Influence of chemical compositions and molecular weights of humic acids on Cr(VI) photo-reduction. JOURNAL OF HAZARDOUS MATERIALS 2011; 197:337-344. [PMID: 22001571 DOI: 10.1016/j.jhazmat.2011.09.091] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/26/2011] [Accepted: 09/26/2011] [Indexed: 05/31/2023]
Abstract
Humic acids (HA) strongly affect the fate of trace metals in soils and aquatic environments. One of the remarkable properties of HA is its ability to reduce Cr(VI), an extremely toxic anion. However, it is unclear which HA components are involved in Cr(VI) reduction and possess the photo-induced properties. In this study, an ultrafiltration technique was used to fractionate HAs into four fractions of different nominal molecular weights (M(w)): >100, 50-100, 10-50 and <10 kDa. Each HA fraction was characterized by spectroscopic analyses followed by examining Cr(VI) removal on each fraction of HA at pH 1-5. Spectroscopic results indicated that low-M(w) HA was enriched with polar and aromatic domains. These polar, including polar C in aliphatic region, and aromatic groups were the major sites for Cr(VI) reduction because they disappeared rapidly upon interaction with Cr(VI). As a result, low M(w) of HA exhibited greater efficiency of Cr(VI) reduction. Light induced the rapid transfer of electrons between chromate-phenol/carboxyl ester, or the formation of peroxide radicals or H(2)O(2) through the ready decay of peroxy radicals associated with polar substituents, explained the rapid scavenging of Cr(VI) on polar and aromatic groups of HAs under illumination.
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Affiliation(s)
- S Y Chen
- Department of Soil & Environmental Sciences, National Chung Hsing University, Taichung, Taiwan, ROC
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González MC, San Román E. Environmental Photochemistry in Heterogeneous Media. THE HANDBOOK OF ENVIRONMENTAL CHEMISTRY 2005. [DOI: 10.1007/b138179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Cavani L, Ciavatta C, Trubetskaya OE, Reznikova OI, Afanas'eva GV, Trubetskoj OA. Capillary zone electrophoresis of soil humic acid fractions obtained by coupling size-exclusion chromatography and polyacrylamide gel electrophoresis. J Chromatogr A 2003; 983:263-70. [PMID: 12568389 DOI: 10.1016/s0021-9673(02)01737-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Capillary zone electrophoresis (CZE) was used for characterisation of soil humic acid (HA) fractions obtained by coupling size-exclusion chromatography with polyacrylamide gel electrophoresis, on the basis of their molecular size and electrophoretic mobility. CZE was conducted using several low alkaline buffers as background electrolyte (BGE): 50 mM carbonate, pH 9.0; 50 mM phosphate, pH 8.5; 50 mM borate, pH 8.3; 50 mM Tris-borate+1 mM EDTA+7 M urea+0.1% sodium dodecyl sulphate (SDS), pH 8.3. Independently of BGE conditions, the effective electrophoretic mobility of HA fractions were in good agreement with their molecular size. The better resolution of HA were obtained in Tris-borate-EDTA buffer with urea and SDS. This results indicated that CZE, mostly with BGE-contained disaggregating agents, is useful for separating HAs in fractions with different molecular sizes.
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Affiliation(s)
- Luciano Cavani
- Department of Agroenvironmental Sciences and Technologies, University of Bologna, 40127 Bologna, Italy.
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Aguer JP, Richard C, Trubetskaya O, Trubetskoj O, Lévèque J, Andreux F. Photoinductive efficiency of soil extracted humic and fulvic acids. CHEMOSPHERE 2002; 49:259-262. [PMID: 12363303 DOI: 10.1016/s0045-6535(02)00282-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Humic and fulvic acids extracted from soils of different genesis were investigated for their ability to photoinduce the transformation of fenuron (2 x 10(-4) mol(-1)) at 365 nm. The ratio of the initial rate of fenuron consumption over the rate of light absorption by humic substances was found to be higher for fulvic acids (range 2.0 x 10(-3) to 9.0 x 10(-5)) than for humic acids (range 1.7 x 10(-4) to - 3.6 x 10(-5)). Within the FAs population, this ratio decreased as the specific absorption coefficient at 365 nm increased. It seems therefore that most of 365-nm absorbing components have no photoinductive activity and even reduce that of photoinductive chromophores.
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Affiliation(s)
- J P Aguer
- Laboratoire de Photochimie Moléculaire et Macromoléculaire, UMR CNRS-Université Blaise Pascal no. 6505, Ensemble Universitaire des Cézeaux, Aubière, France
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