# What research exists on the presence of 6PPD-Q in different environmental media? A systematic map protocol

## TL;DR

This paper outlines a systematic map protocol to identify and catalog research on the presence of 6PPD-Q, a toxic tire chemical, in various environmental media such as water, soil, sediment, and air.

## Contribution

The study introduces a systematic map protocol to comprehensively catalog emerging research on 6PPD-Q in different environmental media.

## Key findings

- A systematic map will be created to track research on 6PPD-Q in environmental media like water, soil, sediment, and air.
- The results will include an open-access database and a global map of study locations and findings.
- The systematic map will follow standardized guidelines and include narrative synthesis and descriptive statistics.

## Abstract

Automobiles are ubiquitous in the modern world, and chemicals leaching from car tires and from the tire wear particles produced during driving can be toxic to the environment, particularly in aquatic ecosystems. 6PPD-Quinone (6PPD-Q), a recently identified tire and tire wear particle leachate, has been identified as highly toxic to coho salmon and other aquatic species. Research on the distribution and impacts of 6PPD-Q in aquatic ecosystems is rapidly developing, while research on 6PPD-Q in other environmental media is just beginning. With research efforts developing on many fronts, there is a need to better map emerging knowledge about this toxin. To do that, we ask the question: “What research exists on the presence of the 6PPD-Q in different environmental media (water (freshwater), soil, sediment, and air, including dust)?” The ultimate purpose of this systematic map is to generate a literature catalog that serves as a searchable database about 6PPD-Q in different environmental media.

The systematic map will follow the Collaboration for Environmental Evidence guidelines and conform to the Reporting Standards for Systematic Evidence Syntheses (ROSES). Relevant English language only literature searches will use a search string using the specified Boolean description of our PECO elements (Population: Environmental media water, soil, sediment, air: including dust; Exposure: N/A; Comparator: N/A; Outcome: The presence of 6PPD-Q/ The concentration of 6PPD-Q). Two bibliographic databases, Web of Science (WOS) Core Collection and ScienceDirect, will be searched. Additional literature will be located through searches of targeted search engines and specialist websites. Screening of titles, abstracts, and full texts will be completed in series using established eligibility criteria. The results of the systematic map will contain a searchable open-access database formatted in Microsoft Excel. Furthermore, the outcome will be presented in a global map of the geographical distribution of included studies and their PICO/PECO elements, including a narrative synthesis, descriptive statistics, tables, and figures.

The online version contains supplementary material available at 10.1186/s13750-026-00380-1.