Environmentally Persistent Free Radicals (EPFRs). 3. Free versus Bound Hydroxyl Radicals in EPFR Aqueous Solutions

Khachatryan, Lavrent; McFerrin, Cheri A.; Hall, Randall W.; Dellinger, Barry

doi:10.1021/es501158r

Cited by 74 publications

(30 citation statements)

References 56 publications

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“…An ˙OH free radical was shown to react with the phosphoric group resulting in the degradation of TCEP by the loss of one oxygen‐ethyl‐chlorine group . Environmentally persistent free radicals have been described to generate reactive oxygen species and ˙OH free radicals in aqueous solutions . In natural waters ˙OH free radicals are generated by sunlight‐dependent reactions of dissolved organic matter with anions and transition metal complexes and by sunlight‐independent oxidation reactions of reduced dissolved organic matter and iron .…”

Section: Resultsmentioning

confidence: 99%

“…62 Environmentally persistent free radicals have been described to generate reactive oxygen species and˙OH free radicals in aqueous solutions. [63][64][65][66] In natural waters˙OH free radicals are generated by sunlight-dependent reactions of dissolved organic matter with anions and transition metal complexes and by sunlight-independent oxidation reactions of reduced dissolved organic matter and iron. [67][68][69][70] The˙OH reactions are also expected to be key to assessing the transformation of OPFRs in aquatic environments and to designing advanced oxidation processes for their removal.…”

Section: Environmental and Public Health Implicationsmentioning

confidence: 99%

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Mass defect filtering for suspect screening of halogenated environmental chemicals: A case study of chlorinated organophosphate flame retardants

Dolios

Patel

Arora

et al. 2019

Rapid Comm Mass Spectrometry

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Rationale Organophosphate flame retardants (OPFRs) are a class of flame retardants widely found in environmental and biological matrices that have been extensively studied due to their adverse health effects in humans. OPFRs are loosely bound chemicals that can detach from treated products and be released into indoor and outdoor environments, where they have the potential to further undergo transformation and degradation processes, in particular the chlorinated OPFRs (Cl‐PFRs). Their detection remains a moving target for analysts, and traditional targeted mass spectrometry methods are suitable only for those compounds with authentic standards. Methods Mass defect filter (MDF) is a strategy to filter molecular features using thresholds applied to the mass defect value of a target ion or molecular feature of interest. We have developed an MDF strategy for the detection and tentative identification of twelve potential Cl‐PFR transformation products in a study mixture of six known Cl‐PFRs using MS/MS data acquired on a high‐resolution mass spectrometer. Most compounds in the Cl‐PFRs family share a ClO4P group as a core structure, of which modification results in a significant shift in the exact masses of the resulting compounds but show only a minimal shift in their mass defects. Subsequently, the MDF strategy was employed to tentatively identify Cl‐PFRs retrospectively in six human urine samples that had previously been analyzed. Results MDF in combination with product ion filtering for the characteristic [H2O3P]+ and [H4O4P]+ ions and neutral loss filtering for the characteristic CnH2n‐xClx group resulted in revealing suspects and homologues in the Cl‐PFRs family. Furthermore, the MDF of the product ions detected additional Cl‐PFR‐related compounds that differed significantly in the exact masses of both precursor and product ions but had minimal shift in the mass defects of product ions. The mass defect of one or more common product ions helped to detect a few Cl‐PFR analogs that had not been identified by MDF of the core structure precursor ion. Conclusions MDF helped to detect some Cl‐PFRs present in lower concentrations, which went undetected without data filters. MDF also helped to detect chromatographic peaks for Cl‐PFR homologues that are likely structural analogs that resulted from impurities and/or derivatives and transformation products. The methodology was applied to demonstrate and tentatively detect known and suspect Cl‐PFRs in human urine samples retrospectively.

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Section: Resultsmentioning

confidence: 99%

Section: Environmental and Public Health Implicationsmentioning

confidence: 99%

Mass defect filtering for suspect screening of halogenated environmental chemicals: A case study of chlorinated organophosphate flame retardants

Dolios

Patel

Arora

et al. 2019

Rapid Comm Mass Spectrometry

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“…DMPO is a typical capture agent for ˙OH, which reacts with ˙OH to produce DMPO-˙OH, a stable paramagnetic adduct with a characteristic line of 1 : 2 : 2 : 1. 35 Four characteristic peaks with a 1 : 2 : 2 : 1 quarter pattern were obtained after irradiation of MTCS and NOM, indicating generation of ˙OH ( Fig. 4 ).…”

Section: Resultsmentioning

confidence: 98%

Inhibitory effects of natural organic matter on methyltriclosan photolysis kinetics

et al. 2018

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This study evaluated the effects and related mechanisms of natural organic matter (NOM) on the photolysis of methyltriclosan (MTCS), a metabolite of triclosan. Addition of two representative NOM isolates, Pony Lake fulvic acid (PLFA-microbial origin) and Suwannee River fulvic acid (SRFA-terrestrial origin), significantly inhibited the direct photolytic rate of MTCS by $70%. The MTCS photolytic rate in the presence of PLFA was greater than for SRFA. NOM not only suppressed photolysis by light-shielding, but also produced ROS to oxidatively degrade MTCS and/or triplet NOM (

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“…•− , hydrogen peroxide H 2 O 2 and hydroxyl radical •OH, which are known to induce toxicity to living organisms by oxidative stress (Dellinger et al 2001;Khachatryan et al 2011Khachatryan et al , 2014Jia et al 2016;Zhu et al 2019). Oxidative stress is usually caused by an imbalance of ROS in exposed cells or tissues (Paul et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Plant and algal toxicity of persistent free radicals and reactive oxygen species generated by heating anthracene-contaminated soils from 100 to 600 °C

et al. 2021

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Persistent free radicals (PFRs) are emerging contaminants of increasing concern, yet their formation, fate, toxicity and health risk are poorly known. Thermal treatment, a common remediation technique to clean industrial soils, induces the formation of PFRs, which could paradoxically increase soil toxicity, contrary to the original objective of remediation. Actually, there is little knowledge on the formation and toxicity of PFRs in soils contaminated by polycyclic aromatic hydrocarbons (PAHs). Here we studied the generation of PFRs of soils spiked with anthracene and heated 1 h from 100 to 600 °C, using electron paramagnetic resonance. We also investigated the formation of reactive oxygen species (ROS), e.g. superoxide radical (O 2•− ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (•OH), in the aqueous phase of thermal-treated soil, and the impact of heating on soil oxidative potential, wheat growth and green algae activity. Results showed that PFRs, ROS, soil oxidative potential, plant toxicity and algal toxicity show a similar trend with an increase from 100 to 300 °C, followed by a decrease to 600 °C. Scavenger trapping tests reveal that algal toxicity is mainly due to the generation of O 2•− , •OH and H 2 O 2 induced by anthracene-PFRs and that anthracene and anthracene-PFRs have negligible direct algal toxicity. Overall, our findings reveal the unintended formation of toxic compounds peaking at 300 °C during the thermal remediation of PAHcontaminated soils. These results should help to assess the environmental risk of thermally treated PAH-contaminated soils.

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Environmentally Persistent Free Radicals (EPFRs). 3. Free versus Bound Hydroxyl Radicals in EPFR Aqueous Solutions

Cited by 74 publications

References 56 publications

Mass defect filtering for suspect screening of halogenated environmental chemicals: A case study of chlorinated organophosphate flame retardants

Mass defect filtering for suspect screening of halogenated environmental chemicals: A case study of chlorinated organophosphate flame retardants

Inhibitory effects of natural organic matter on methyltriclosan photolysis kinetics

Plant and algal toxicity of persistent free radicals and reactive oxygen species generated by heating anthracene-contaminated soils from 100 to 600 °C

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