The Tire Wear Compounds 6PPD-Quinone and 1,3-Diphenylguanidine in an Urban Watershed

Abstract

Prompted by a recent report that 6PPD-quinone (6PPD-q), a by-product of a common tire manufacturing additive that is present in road runoff, is toxic to coho salmon ( Oncorhynchus kisutch ), extracts of water samples collected from an urban river were re-analyzed to determine if this compound was present in stormwater-influenced flows. In addition, extracts were analyzed for 1,3-diphenylguanidine (DPG), which is also used in tire manufacturing. Samples were originally collected in the fall of 2019 and winter of 2020 in the Greater Toronto Area of Canada from the Don River, a highly urbanized watershed in close proximity to several major multi-lane highways. These target compounds were analyzed using ultra-high pressure liquid chromatography with high resolution mass spectrometric detection with parallel reaction monitoring. Both 6PPD-q and DPG were detected above limits of quantification (i.e., 0.0098 µg/L) in all extracts. Maximum concentrations for 6PPD-quinone of 2.30 ± 0.05 µg/L observed in the river during storm events exceeded the LC 50 for this compound for coho salmon (i.e., > 0.8 µg/L). In composite samples collected at intervals throughout one rain event, both compounds reached peak concentrations a few hours after initiation of the event (i.e., 0.52 µg/L for DPG and 2.85 µg/L for 6PPD-q), but the concentrations of 6PPD-q remained elevated above 2 µg/L for over 10-h in the middle of the event. Estimates of cumulative loads of these compounds in composite samples indicated that kg amounts of these compounds entered the Don River during each hydrological event, and the loads were proportional to the amounts of precipitation. This study contributes to the growing literature indicating that potentially toxic tire-wear compounds are present at elevated levels and are transported via road runoff into urban surface waters during rain events. Supplementary Information The online version contains supplementary material available at 10.1007/s00244-021-00878-4.

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

“…Recently, a quinone derivative of the tire rubber antioxidant N -(1,3-dimethylbutyl)- N ′-phenyl-PPD (6PPD) formed by oxidative transformation, termed 6PPD-quinone, has attracted considerable international attention on PPDs because 6PPD-quinone was identified as the toxicant responsible for acute mortality in the Pacific Northwest coho salmon . Subsequent studies have confirmed the ubiquitous occurrence of 6PPD and 6PPD-quinone in stormwater runoff, surface waters, air particles, and dust. − The same pathway may also produce quinones from other PPDs. A more recent study provided new evidence of multiple PPD-derived quinones in environmental media .…”

Urban Roadway Runoff Is Lethal to Juvenile Coho, Steelhead, and Chinook Salmonids, But Not Congeneric Sockeye

“… 1 , 2 Many are essentially unknown to ecotoxicology despite an apparent prevalence in the environment 3 , 4 and rapid mobilization in stormwater runoff. 5 − 7 One such CEC is N -(1,3-dimethylbutyl)- N ′-phenyl- p -phenylenediamine (6PPD), an antiozonant added during the manufacture of tires to help prevent tread degradation. Ozone abiotically converts 6PPD into 6PPD-quinone, as well as other transformation products.…”

Environmental Fate and Effects of Road Run-Off

“…Significant differences in toxicity between de-icing products were reported, as well as increased toxicity to mayfly larvae at higher temperatures (15 °C) compared to lower temperatures (4–7 °C). Regarding toxicity of tire wear compounds and particles, Johannessen et al ( 2022b ) reported that the maximum levels of 6PPD-quinone in an urban river during storm events exceeded the previously reported LC50 for this compound for Coho salmon (Tian et al 2021 ). However, Navarro et al ( 2022 ) found that microplastics derived from tire rubber were not harmful to sediment-dwelling oligochaetes and insect larvae.…”

“…Johannessen et al ( 2022a ) demonstrated that hexamethoxymethyl-melamine (HMMM), a compound which is used in the manufacture of tires and is included in the US Environmental Protection Agencies “High Production Volume Challenge Program” is discharged during rain events into urban watersheds in the Greater Toronto Area in Canada. In addition, in another contribution, Johannessen et al ( 2022b ) reported that two other tire wear compounds, 6PPD-quinone and 1,3-diphenylguanidine, are also present at µg/L concentrations in these urban watersheds and these authors predicted that for each hydrological event, the cumulative loads of these compounds entering urban surface water are in kg amounts. This is alarming as Tian et al ( 2021 ) recently reported that 6PPD-quinone is toxic to Coho salmon at concentrations < 1 µg/L.…”