Is 6PPD a toxic oxidant?

To enhance tire durability, the antioxidant N- (1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) is used in rubber, but it converts into the toxic 6PPD quinone (6PPD-Q) when exposed to oxidants like ozone (O 3), causing ecological concerns.

What causes 6ppd-q in soil & tire rubber wear particles (trwps)?

There is a linkage between 6PPD-Q in soil and tire rubber wear particles (TRWPs), indicating its origin from sources associated with vehicular activities (Klockner et al., 2019). Approximately 50% of TRWPs can infiltrate the soil, releasing bound chemicals like 6PPD (Klockner et al., 2019).

Why is 6PPD important?

Globally the increasing demand for rubber tires leads to the extensive consumption of 6PPD up to millions of tons resulting in significant release of this compound from tire rubber to the environment (Rossomme et al., 2023).

Is 6ppd-q bioavailable?

The bioavailability of these chemicals, particularly the transformation of 6PPD to 6PPD-Q, poses significant ecological risks. 6PPD-Q is highly bioavailable in aquatic environments, indicating its potential for widespread ecological harm.

What is the difference between 6ppd-q and 6ppd-q?

6PPD-Q exhibits greater stability compared to 6PPD. Hiki et al. (2021) demonstrated this by observing that, at room temperature, the half-life of 6PPD-Q was significantly longer at 33 h compared to 6PPD's half-life of 5 h. Additionally, when exposed to ozone, the unstable 6PPD transforms into the more stable 6PPD-Q.

Why is 6ppd-q present in soil?

The presence of 6PPD-Q in soil predominantly arises from the deposition of atmospheric particles or dust that carry 6PPD-Q. Soil samples collected from Hongkong's New Territories and Kowloon roadside showed varied concentrations of 6PPD-Q like 9.50–936 ng/g (Cao et al., 2022).