Occurrence, Fate, Bioaccumulation and Toxic Effects of 6PPDQ

A special issue of Toxics (ISSN 2305-6304). This special issue belongs to the section "Emerging Contaminants".

Deadline for manuscript submissions: 10 July 2026 | Viewed by 3824

Special Issue Editors


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School of Environment, South China Normal University, Guangzhou 510006, China
Interests: emerging organic pollutants; marine pollution; marine environmental geochemistry; ecological risk assessment
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Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
Interests: emerging organic pollutants; bioaccumulation; trophic magnification; biotransformation; human exposure
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Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, China
Interests: environmental toxicology; nanotoxicology; microplastics; emerging contaminants; mechanism-specific toxicity; pharmacology
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Special Issue Information

Dear Colleagues,

6PPD-quinone (6PPDQ) is a transformation product of the tire rubber antioxidant 6PPD (N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine) that has gained significant attention due to its extreme toxicity to certain aquatic species, particularly coho salmon (Oncorhynchus kisutch). Its presence in municipal stormwater has caused the acute mortality of coho salmon when they migrate to urban creeks to reproduce. Studying its occurrence and toxicity in the environment is of global significance. The many unanswered questions about 6PPDQ necessitate further research.

This Special Issue of Toxics is dedicated to advancing knowledge on the occurrence, fate, bioaccumulation, and toxic effects of 6PPDQ. We invite original research articles, reviews, and case studies that address critical aspects of this field.

Prof. Dr. Yuxin Sun
Prof. Dr. Xiaojun Luo
Prof. Dr. Dayong Wang
Guest Editors

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Keywords

  • 6PPDQ
  • environmental behavior
  • bioaccumulation
  • toxicity
  • human exposure
  • transformation product
  • risk assessment

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Published Papers (2 papers)

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Research

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17 pages, 2481 KB  
Article
6-PPD Quinone Inhibits Phosphatidic Acid Synthesis Associated with an Increase in Intestinal Barrier Permeability in C. elegans
by Jingwei Wu, Qian Bian and Dayong Wang
Toxics 2026, 14(3), 254; https://doi.org/10.3390/toxics14030254 - 12 Mar 2026
Viewed by 724
Abstract
6-PPD quinine (6-PPDQ) affects intestinal barrier function; however, its underlying mechanisms remain largely unknown. In the current study, we examined the role of reduction in phosphatidic acid synthesis in mediating the toxicity of 6-PPDQ in affecting intestinal barrier function. In Caenorhabditis elegans, [...] Read more.
6-PPD quinine (6-PPDQ) affects intestinal barrier function; however, its underlying mechanisms remain largely unknown. In the current study, we examined the role of reduction in phosphatidic acid synthesis in mediating the toxicity of 6-PPDQ in affecting intestinal barrier function. In Caenorhabditis elegans, 6-PPDQ exposure reduced the phosphatidic acid content, which was accompanied by the decreased expression of acl-5 and acl-6 encoding glycerol-3-phosphate acyltransferase. The RNAi of acl-5 and acl-6 lowered the phosphatidic acid content, enhanced intestinal permeability, and resulted in the increased accumulation of 6-PPDQ. Meanwhile, acl-5 and acl-6 RNAi caused susceptibility to 6-PPDQ toxicity by upregulating the expressions of insulin ligands and receptor genes and downregulating the expressions of daf-16 and its target genes. Moreover, the RNAi of acl-5 and acl-6 elevated the expression of let-363, and the RNAi of let-363 could reduce the expressions of insulin ligand genes and confer resistance to 6-PPDQ toxicity. The double RNAi of acl-5 and acl-6 caused more severe enhanced intestinal permeability and 6-PPDQ toxicity. Therefore, 6-PPDQ exposure potentially disrupts phosphatidic acid synthesis to affect intestinal barrier function by downregulating acl-5 and acl-6 expressions. Full article
(This article belongs to the Special Issue Occurrence, Fate, Bioaccumulation and Toxic Effects of 6PPDQ)
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Review

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23 pages, 795 KB  
Review
Environmental Occurrence, Influencing Factors, and Toxic Effects of 6PPD-Q
by Tengwen Yin, Ying Liang, Yanju Liu, Jia Liu and Xuedong Wang
Toxics 2025, 13(11), 906; https://doi.org/10.3390/toxics13110906 - 22 Oct 2025
Cited by 4 | Viewed by 2617
Abstract
The antioxidant N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) is widely incorporated into tires to extend their service life. However, in the presence of ozone, it is readily transformed into N-(1,3-dimethylbutyl)-N′-phenyl-p-benzoquinone (6PPD-Q). Owing to the large-scale production and [...] Read more.
The antioxidant N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) is widely incorporated into tires to extend their service life. However, in the presence of ozone, it is readily transformed into N-(1,3-dimethylbutyl)-N′-phenyl-p-benzoquinone (6PPD-Q). Owing to the large-scale production and widespread utilization of rubber-related products, 6PPD-Q is continuously released into the environment with tire and road wear particles, becoming ubiquitous across multiple environmental compartments. It possesses bioaccumulation potential and exhibits significant toxicity, while multiple exposure pathways enable it to enter human body, posing risks to public health. This review summarizes the environmental distribution of 6PPD-Q in atmospheric, aquatic, and terrestrial systems, and examines key factors influencing its occurrence, including precipitation patterns, traffic characteristics, sunlight, and particle size. The toxicological effects of 6PPD-Q are also discussed. Based on these findings, a comprehensive management framework encompassing “source reduction—process regulation—end-of-pipe treatment” is proposed. Finally, current knowledge gaps are identified and future research directions are highlighted. Full article
(This article belongs to the Special Issue Occurrence, Fate, Bioaccumulation and Toxic Effects of 6PPDQ)
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