Widespread N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine Quinone in Size-Fractioned Atmospheric Particles and Dust of Different Indoor Environments

Our previous work demonstrated that massive emissions of hindered phenol antioxidants and sulfur-containing antioxidants from e-waste recycling; however, it remains unclear whether e-waste recycling also results in the emission of substantial quantities of amine antioxidants (AAs) and organophosphite antioxidants (OPAs), another two major classes of under-researched antioxidants. In this study, we continued to screen the previously studied e-waste dusts for a broad range of 21 AAs, two p-phenylenediamine-derived quinones, and 15 OPAs. All 21 AAs and 12 out of the 15 OPAs were detected in the samples, with the total concentrations ranging from 511 to 10,600 ng/g for AAs and from 155 to 33,200 ng/g for OPAs. Among the detected chemicals, nine were identified for the first time in the environment. More importantly, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-quinone), the causal toxicant of acute mortality in coho salmon, was pervasively detected with greater environmental abundance (median: 375 ng/g) than its parent chemical 6PPD (median: 113 ng/g), demonstrating that e-waste as another source of ubiquitous 6PPD-quinone in addition to tire rubber. Waste wires, cables, and electronic plastics were identified as the main sources for e-waste-derived AAs and OPAs. Our work highlights a large group of antioxidant chemicals, including their transformation products, as emerging e-waste pollutants that require more attention.

Section: Introductionmentioning

confidence: 99%

E-Waste Recycling Emits Large Quantities of Emerging Aromatic Amines and Organophosphites: A Poorly Recognized Source for Another Two Classes of Synthetic Antioxidants

Liang

et al. 2022

“…However, to the best of our knowledge, the detailed toxicity mechanism of 6PPD-Q is still unknown. Zhang et al investigated human exposure to 6PPD-Q via inhalation using simulations and demonstrated an accumulation of the contaminant in the upper respiratory tract . Recently, our study has revealed a series of other PM 2.5 -bonded PPD-quinones in addition to 6PPD-Q, which also ubiquitously occurred in urban runoff and roadside soil .…”

Section: Introductionmentioning

confidence: 51%

“…Zhang et al investigated human exposure to 6PPD-Q via inhalation using simulations and demonstrated an accumulation of the contaminant in the upper respiratory tract. 21 Recently, our study has revealed a series of other PM 2.5 -bonded PPDquinones in addition to 6PPD-Q, which also ubiquitously occurred in urban runoff and roadside soil. 20 Given that atmospheric quinones are an important redox-active component that would cause oxidative stress in living organisms, it is highly possible that these emerging quinones could contribute to a certain amount of OP caused by PM 2.5 .…”

Section: ■ Introductionmentioning

confidence: 79%

“…Emerging evidence has indicated the occurrence of tire rubber-added p -phenylenediamine-derived quinones (PPD-quinones) in PM 2.5 . − One of these PPD-quinones, N -(1,3-dimethylbutyl)- N ′-phenyl- p -phenylenediamine quinone (6PPD-Q), which originates from the oxidation of a tire rubber antioxidant, was proven to be highly toxic to aquatic organisms, including coho salmon, rainbow trout, and brook trout. , In addition, a toxicological study indicated that exposure to 6PPD-Q can cause reddening in the lumen of the intestine of zebrafish, a typical symptom of inflammation . However, to the best of our knowledge, the detailed toxicity mechanism of 6PPD-Q is still unknown.…”

Section: Introductionmentioning

confidence: 99%

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p-Phenylenediamine-Derived Quinones as New Contributors to the Oxidative Potential of Fine Particulate Matter

Wang

Cao

Zhang

et al. 2022

Atmospheric fine particulate matter (PM 2.5 ) has been linked to multiple adverse outcomes, where redox-active species-induced oxidative stress is recognized as an important driver of its biotoxicity. Previous studies have proven that the oxidative potential (OP) is a relevant metric for specific acute PM 2.5 health effects and is associated with various toxicants, especially organic quinones. However, discrepancies between OP induced by the known components and its total levels caused by PM 2.5 remain. Here, we investigated the OP values of a suite of emerging contaminants, five p-phenylenediamine-derived quinones (PPD-quinones), in PM 2.5 using the acellular dithiothreitol (DTT) assay and evaluated their contributions to the total PM 2.5 -induced OP in five megacities in China. N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-Q), a highly toxic quinone responsible for "urban runoff mortality syndrome", was found to exhibit moderate OP with a DTT consumption rate of 1.70 μM min −1 μM −1 . Meanwhile, it is noteworthy that the estimated OP contribution of the five PPD-quinones was 2.9 ± 2.7% of the total PM 2.5 -induced OP. This is the first study that reveals a considerable OP induced by the emerging PPD-quinones in urban PM 2.5 . The data improve our understanding of the toxicity of both PM 2.5 and PPD-quinones, which is illuminating for further assessment of the environmental risk they pose.

“…For example, an environmental transformation product of a phenyldiamine-based tire rubber antioxidant additive (6PPD quinone) was recently linked to mass mortalities of salmon returning to spawn in the U.S. Pacific Northwest . It and precursors have also been detected in indoor dust, especially within vehicles . Another example of unintentionally produced contaminants, PFAS residuals, arose from treatment of high-density polyethylene pesticide storage containers with fluorine gas (to reduce their permeability)…”

Section: Trends In Global Chemical Production and Environmental Conta...mentioning

confidence: 99%

Durable Plastic Goods: A Source of Microplastics and Chemical Additives in the Built and Natural Environments

Hale¹,

King²,

Ramirez³

et al. 2022

Marine plastic pollution by single-use packaging is an emerging concern. However, more than half of all plastics manufactured are designed and utilized for longer-term uses (e.g., as indoor furnishings, insulation, electrical devices, conduits, and textiles). Such durable plastics are more likely to contain persistent, bioaccumulative, and toxic chemical additives (PBTs). Considerable additives and polymer fragments are released into enclosed indoor spaces over the service lives of these plastic products, with resultant human exposure, and then pass to wastewater treatment plants. However, globally only approximately half of all wastewaters receive any treatment. For affluent nations, efficiencies of removal of microplastics and PBTs of ≥90% are commonly quoted for effluents, but some wastewaters therein receive primary or less treatment. Regardless, PBTs and microplastics largely survive even sophisticated treatment, and most are deposited into settled solids. Such “biosolids” may then be repurposed to enrich soils due to their nutrient content. Associated contaminants may affect soil communities and later be dispersed via hydrologic and aeolian processes. To date, regulatory efforts have been insufficient to stem microplastic and additive emissions to air, water, and soils. Upgrading wastewater treatment to tertiary and excluding floating or primary settled solids from land-applied biosolids would substantially reduce releases of these contaminants.