The Tire-Derived Chemical 6PPD-quinone Is Lethally Toxic to the White-Spotted Char <i>Salvelinus leucomaenis pluvius</i> but Not to Two Other Salmonid Species

Hiki, Kyoshiro; Yamamoto, Hiroshi

doi:10.1021/acs.estlett.2c00683

Cited by 56 publications

(78 citation statements)

References 38 publications

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“…Five other 6PPD‐Q studies have reported species LC50 values that were greater than the highest test concentration in the present study (Table 1); however, all authors noted that at the highest concentration, no mortalities were observed. In our study, the Chinook LC5 is estimated at 12 614 ng/L (CI: 7293–17 934 ng/L) suggesting that Chinook is more sensitive to 6PPD‐Q than Arctic char, white sturgeon (both no mortality at 12 700 ng/L; Brinkmann et al, 2022), southern Asian dolly varden, masu salmon (both no mortality at 10 000 ng/L; Hiki & Yamamoto, 2022), Japanese medaka (no mortality at 34 000 ng/L), and zebrafish (no mortality at 54 000 ng/L; Hiki et al, 2021). Varshney et al (2022) reported a zebrafish 96‐h LC50 of 309 000 ng/L; however, measured 6PPD‐Q concentrations were not reported.…”

Section: Resultsmentioning

confidence: 56%

Acute Toxicity of 6PPD‐Quinone to Early Life Stage Juvenile Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) Salmon

Marlatt

Liu

et al. 2023

Enviro Toxic and Chemistry

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The breakdown product of the rubber tire antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD)-6-PPD-quinone has been strongly implicated in toxic injury and death in coho salmon (Oncorhynchus kisutch) in urban waterways. Whereas recent studies have reported a wide range of sensitivity to 6PPD-quinone in several fish species, little is known about the risks to Chinook salmon (Oncorhynchus tshawytscha), the primary prey of endangered Southern Resident killer whales (Orcinus orca) and the subject of much concern. Chinook face numerous conservation threats in Canada and the United States, with many populations assessed as either endangered or threatened. We evaluated the acute toxicity of 6PPD-quinone to newly feeding (~3 weeks post swim-up) juvenile Chinook and coho. Juvenile Chinook and coho were exposed for 24 h under static conditions to five concentrations of 6PPD-quinone. Juvenile coho were 3 orders of magnitude more sensitive to 6PPDquinone compared with juvenile Chinook, with 24-h median lethal concentration (LC50) estimates of 41.0 and more than 67 307 ng/L, respectively. The coho LC50 was 2.3-fold lower than what was previously reported for 1+-year-old coho (95 ng/L), highlighting the value of evaluating age-related differences in sensitivity to this toxic tire-related chemical. Both fish species exhibited typical 6PPD-quinone symptomology (gasping, increased ventilation, loss of equilibrium, erratic swimming), with fish that were symptomatic generally exhibiting mortality. The LC50 values derived from our study for coho are below concentrations that have been measured in salmon-bearing waterways, suggesting the potential for population-level consequences in urban waters. The higher relative LC50 values for Chinook compared with coho merits further investigation, including for the potential for population-relevant sublethal effects.

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Section: Resultsmentioning

confidence: 56%

Acute Toxicity of 6PPD‐Quinone to Early Life Stage Juvenile Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) Salmon

Marlatt

Liu

et al. 2023

Enviro Toxic and Chemistry

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“…Recently, our group identified 6PPD-quinone (6PPDQ), a highly toxic (LC 50 for coho salmon, white-spotted char, and brook and rainbow trout: 95–1000 ng/L) ozone (O 3 )-derived transformation product of 6PPD ( N -(1,3-dimethylbutyl)- N ′-phenyl- p -phenylenediamine); − 6PPDQ has now been detected globally in water, − dust, − and air samples. − 6PPD is ubiquitously used in tire rubbers as an antioxidant at 0.4–2% by weight, where it is designed to quickly react with ground-level O 3 to protect rubber elastomers. , Such reactions inevitably form other transformation products (TPs) beyond 6PPDQ during the tire rubber lifetime. , For example, early studies on the antioxidant efficacy of 6PPD (e.g., Lattimer et al) proposed several ozonation TPs based on low-resolution mass spectrometry and associated data . Recently, using high-resolution mass spectrometry (HRMS), Klöckner et al identified 6PPD-related chemical features as markers of tire and road wear particles, and Hu et al used gas-phase ozonation experiments to generate candidate feature lists for 6PPD TPs .…”

Section: Introductionmentioning

confidence: 99%

Transformation Products of Tire Rubber Antioxidant 6PPD in Heterogeneous Gas-Phase Ozonation: Identification and Environmental Occurrence

Zhao

Tian

et al. 2023

Environ. Sci. Technol.

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6PPD, a tire rubber antioxidant, poses substantial ecological risks because it can form a highly toxic quinone transformation product (TP), 6PPD-quinone (6PPDQ), during exposure to gas-phase ozone. Important data gaps exist regarding the structures, reaction mechanisms, and environmental occurrence of TPs from 6PPD ozonation. To address these data gaps, gas-phase ozonation of 6PPD was conducted over 24–168 h and ozonation TPs were characterized using high-resolution mass spectrometry. The probable structures were proposed for 23 TPs with 5 subsequently standard-verified. Consistent with prior findings, 6PPDQ (C18H22N2O2) was one of the major TPs in 6PPD ozonation (∼1 to 19% yield). Notably, 6PPDQ was not observed during ozonation of 6QDI (N-(1,3-dimethylbutyl)-N′-phenyl-p-quinonediimine), indicating that 6PPDQ formation does not proceed through 6QDI or associated 6QDI TPs. Other major 6PPD TPs included multiple C18H22N2O and C18H22N2O2 isomers, with presumptive N-oxide, N,N′-dioxide, and orthoquinone structures. Standard-verified TPs were quantified in roadway-impacted environmental samples, with total concentrations of 130 ± 3.2 μg/g in methanol extracts of tire tread wear particles (TWPs), 34 ± 4 μg/g-TWP in aqueous TWP leachates, 2700 ± 1500 ng/L in roadway runoff, and 1900 ± 1200 ng/L in roadway-impacted creeks. These data demonstrate that 6PPD TPs are likely an important and ubiquitous class of contaminants in roadway-impacted environments.

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“…13−17 Confoundingly, many other Salmoninae species are not sensitive, and overall species sensitivity does not appear to have a discernible pattern with established species phylogenies. 15,16,18 Within the sensitive species, coho salmon are approximately five times more sensitive (24 h LC 50 95 ng/L) to mortality than any other species that have been evaluated. 19,20 The presence of PPDs and quinone transformation products in the water, air, and soils also presents an opportunity for exposure in terrestrial animals including humans.…”

Section: ■ Introductionmentioning

confidence: 99%

Establishing an In Vitro Model to Assess the Toxicity of 6PPD-Quinone and Other Tire Wear Transformation Products

Greer

Dalsky

Lane

et al. 2023

Environ. Sci. Technol. Lett.

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The tire wear transformation product 6PPD-quinone (6PPDQ) has been implicated as the causative factor for broad scale mortality events for coho salmon in the Pacific Northwest. Highly variable sensitivity to 6PPDQ in closely related salmonids complicates efforts to evaluate the broader toxicological impacts to aquatic ecosystems. Our goals were to (1) validate the large range of in vivo species sensitivities reported for coho, Chinook, and sockeye salmon and (2) develop an in vitro platform for assessing 6PPDQ toxicity. In vivo studies confirmed the acute sensitivity of juvenile coho (12 h LC50 = 80.4 ng/L) and demonstrated that sockeye salmon were not vulnerable to mortality. Chinook salmon were sensitive to 6PPDQ mortality at initial concentrations >25 μg/L, ∼10-fold greater than reported environmental measurements. In vitro, the coho salmon cell line CSE-119 was acutely sensitive to 6PPDQ (metabolic EC50 = 7.9 μg/L, cytotoxicity EC50 = 6.1 μg/L). Analogous Chinook (CHSE-214) and sockeye salmon (SSE-5) cell lines were nonresponsive in both assays, and rainbow trout RTG-2 cells began showing metabolic effects at 68 μg/L (EC5). Recreation of species-specific 6PPDQ sensitivity in vitro implicates conserved modes of action in CSE-119 that could be utilized for mechanistic studies of 6PPDQ toxicity and screening of other PPD transformation products.

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The Tire-Derived Chemical 6PPD-quinone Is Lethally Toxic to the White-Spotted Char Salvelinus leucomaenis pluvius but Not to Two Other Salmonid Species

Cited by 56 publications

References 38 publications

Acute Toxicity of 6PPD‐Quinone to Early Life Stage Juvenile Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) Salmon

Acute Toxicity of 6PPD‐Quinone to Early Life Stage Juvenile Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) Salmon

Transformation Products of Tire Rubber Antioxidant 6PPD in Heterogeneous Gas-Phase Ozonation: Identification and Environmental Occurrence

Establishing an In Vitro Model to Assess the Toxicity of 6PPD-Quinone and Other Tire Wear Transformation Products

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