The retracted review concerned a class of pollutants with genuine toxicological importance. Polycyclic aromatic hydrocarbons, often abbreviated PAHs, are a large family of organic compounds composed of fused aromatic rings. They form whenever organic material is incompletely burned, which means that the dominant human exposure routes include tobacco smoke, charred and grilled food, wood and coal combustion, vehicle exhaust, and a wide range of occupational settings such as asphalt paving, coking, and aluminum smelting. Because many PAHs are lipophilic and are metabolized in the liver, the organ is both the principal site of their biotransformation and a plausible target for their toxic effects. Enzymes of the cytochrome P450 family convert parent PAHs into reactive metabolites, some of which form DNA adducts and protein adducts, generate oxidative stress, and can disturb hepatocellular function. Serum markers such as alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase are therefore commonly used in environmental epidemiology as indirect indicators of liver injury in populations exposed to air pollution.

Against that background, a systematic review of observational studies examining PAH exposure and liver function would have been a useful contribution, since observational evidence in this field is scattered across occupational cohorts, general-population surveys, and studies using biomarkers of internal dose such as urinary hydroxylated PAH metabolites. The retraction does not establish that the underlying hypothesis is wrong; rather, it removes this particular synthesis from the citable literature because the journal can no longer vouch for its integrity. That distinction matters for readers who encounter the paper through search engines or reference managers: the retraction notice is now attached to the article record, and the canonical digital object identifier for the notice itself is 10.1007/s11869-026-02101-6, while the original article was published under a different identifier in 2023.

The first ground for retraction, substantial overlap with a previously published article, points to one of the most closely watched problems in contemporary scholarly publishing. Textual and data overlap between papers can range from redundant publication, in which the same work is submitted to multiple journals, to outright plagiarism, in which text or findings are reused without attribution. In this case, the journal identified the overlapping publication as a paper that itself has since been retracted: a systematic review on the association between prenatal exposure to polycyclic aromatic hydrocarbons and childhood intelligence, published in Environmental Science and Pollution Research in 2023, which the notice explicitly labels as a retracted article. Two authors were common to both papers. The fact that the companion article was also retracted suggests a broader pattern in which a cluster of related manuscripts, produced by large and geographically dispersed author teams, came under editorial scrutiny at more than one journal.

The second ground, that multiple references appeared to be irrelevant, is a hallmark that research-integrity specialists associate with certain forms of coordinated manuscript production. Citation manipulation, whether intended to inflate the metrics of particular journals or authors, or simply the byproduct of template-driven writing, undermines the scholarly function of a reference list, which is supposed to document the evidentiary basis of a review’s claims. In a systematic review, where the entire contribution depends on the transparent identification, screening, and synthesis of primary studies, irrelevant citations are not a cosmetic flaw. They make it impossible for readers to verify which studies were actually considered, how inclusion and exclusion criteria were applied, and whether the pooled conclusions follow from the evidence. When such problems surface and authors decline to engage with the journal, editors are left with little alternative to retraction.

The authorship pattern of the retracted paper is itself noteworthy. The article listed authors affiliated with institutions in Indonesia, Saudi Arabia, Russia, Iraq, India, Colombia, Poland, Yemen, Uzbekistan, and Iran, a span of countries that would be unusual for a review of environmental health data focused on any single population. Large, internationally scattered author lists with limited apparent connection to the study subject have become a recognized red flag in the wave of retractions that has swept through the scientific literature in recent years, particularly among papers produced by commercial paper mills. Publication ethics watchdogs and major publishers have documented tens of thousands of retractions in recent years, a substantial fraction of them linked to systematic manipulation of the publishing pipeline rather than to honest error. While the retraction notice in this case does not allege paper-mill involvement, the combination of overlapping text, irrelevant references, and non-response from a dozen or more authors fits a familiar profile.

The non-response of the authors is a significant procedural element. Journals typically follow a due-process protocol when integrity concerns arise: they contact the corresponding authors, describe the concerns, and invite an explanation or rebuttal, sometimes allowing weeks or months for a reply. When authors engage, the outcome may be a correction, an expression of concern, or, if the explanation is unsatisfactory, retraction. When authors do not respond at all, editors must weigh the harm of leaving a flawed paper in the literature against the fairness of acting without the authors’ side of the story. In this instance the Editor-in-Chief concluded that the evidence of overlap and citation problems, combined with the authors’ silence, justified withdrawal of the article and a public statement that confidence in the work could no longer be maintained. The notice also records that none of the authors responded to the publisher’s correspondence about the retraction itself.

For the environmental health community, the retraction carries practical consequences. Systematic reviews are frequently cited in risk assessments, in the design of subsequent studies, and in policy documents that summarize the state of the evidence on pollutant-health associations. A retracted review on PAHs and liver function cannot be used as a summary of that evidence, and researchers citing the field should rely on the primary observational studies and on reviews that have survived editorial scrutiny. At the same time, the underlying scientific question remains open and legitimate. Epidemiologists continue to investigate whether chronic low-level PAH exposure, as measured by urinary metabolites or by proxies such as traffic-related air pollution, is associated with altered liver enzymes, non-alcoholic fatty liver disease, or other hepatic outcomes. Well-conducted reviews that document their search strategies, register their protocols, and report their screening decisions transparently remain the right tool for answering that question.

The episode also illustrates the machinery of post-publication correction that major publishers now deploy. The retraction notice is linked to the article record through the CrossMark service, which allows readers checking a document to verify whether they are viewing the current, authoritative version. The notice identifies the journal, the volume and article number, the publication date, and the relationship to the original paper, and it cites the retracted companion article explicitly so that readers can trace the overlap. This apparatus does not erase the flawed paper from databases, since retracted articles remain online with their notices attached; that permanence is deliberate, preserving the scholarly record while warning readers away from relying on the content. It also creates a public trail that institutions can consult when evaluating the output of researchers involved in retractions.

Ultimately, the case is a reminder that the credibility of environmental health science depends as much on the integrity of synthesis as on the quality of the underlying measurements. Air pollution research has produced some of the most consequential public health findings of the past decades, linking fine particulate matter, nitrogen dioxide, and combustion byproducts to cardiovascular, respiratory, and metabolic disease, and PAHs remain a plausible contributor to hepatic toxicity given their metabolism in the liver and their capacity to form reactive adducts. But every meta-analytic claim inherits the weaknesses of the papers it aggregates, and a review built on irrelevant citations and duplicated material cannot support confident conclusions. The retraction of this systematic review removes a compromised summary from the literature, flags a cluster of related concerns across at least two journals, and underscores the growing vigilance of editors and integrity researchers toward the patterns of overlap, citation manipulation, and authorial silence that have come to define the current era of scholarly self-correction.

Subject of Research: Retraction of a systematic review on polycyclic aromatic hydrocarbon exposure and liver function due to article overlap and citation integrity concerns

Article Title: Retraction Note: Exposure to polycyclic aromatic hydrocarbons and liver function: a systematic review of observational studies

Article References: Retraction Note: Exposure to polycyclic aromatic hydrocarbons and liver function: a systematic review of observational studies. (n.d.). https://doi.org/10.1007/s11869-026-02101-6

Image Credits: AI Generated

DOI: 10.1007/s11869-026-02101-6

Keywords: retraction, polycyclic aromatic hydrocarbons, liver function, systematic review, research integrity, Air Quality Atmosphere & Health, citation manipulation, environmental health, hepatotoxicity, air pollution, Springer Nature, publishing ethics