Early-life exposure to a common pollutant harms fish development across generations

(Press-News.org) A widely distributed environmental pollutant can leave lasting biological scars that persist long after direct exposure has ended, according to a new study that tracked its effects across multiple generations of fish.

Researchers found that brief exposure to benzo[a]pyrene, a toxic compound produced by fossil fuel combustion and industrial activity, disrupted normal development and skeletal health not only in directly exposed fish but also in their unexposed descendants. The study reveals that these long-term effects are driven by persistent changes in metabolism, shedding new light on how early-life pollution can shape health outcomes across generations.

Benzo[a]pyrene is a type of polycyclic aromatic hydrocarbon commonly detected in air, soil, and aquatic environments worldwide. While its toxic effects are well documented, most studies focus on immediate or single-generation impacts. This new research goes further by examining how early embryonic exposure influences offspring two generations later.

Using medaka fish, a well-established model for environmental and developmental research, scientists exposed embryos to environmentally relevant concentrations of benzo[a]pyrene for just the first eight days of development. The fish were then raised in clean water, and their offspring and grand-offspring were never directly exposed to the chemical.

Despite this, the effects persisted.

The researchers observed reduced survival and delayed hatching in the directly exposed generation. More strikingly, offspring across two generations showed altered body size, abnormal organ development, and a high frequency of skeletal deformities, including craniofacial abnormalities and spinal curvature.

“Our results show that a short window of exposure early in life can have consequences that echo across generations,” said Jiezhang Mo, the corresponding author of the study. “Even when later generations grow up in clean environments, they still carry hidden biological costs from their ancestors’ exposure.”

To understand why these effects persist, the team conducted untargeted metabolomic analyses, a technique that measures hundreds of small molecules involved in metabolism. This approach allowed them to link physical abnormalities with disruptions in core biological processes.

They identified widespread changes in pathways related to energy production, oxidative stress, cell signaling, and developmental programming. Key metabolic signals suggested that exposed fish embryos entered an energy crisis, forcing them to reallocate limited resources to support survival-critical organs at the expense of skeletal development.

“In the second generation, some physical traits appeared to recover, but our metabolic data tell a different story,” Mo explained. “This apparent recovery may reflect a survival trade-off, where energy is diverted away from bone formation to keep essential systems functioning.”

The study also identified specific metabolic signatures that could serve as early warning indicators of long-term toxicity. These biomarkers provide a mechanistic bridge between early chemical exposure and delayed health effects, helping explain why damage can remain hidden until later stages of development or even future generations.

The findings have important implications beyond fish. Benzo[a]pyrene is a ubiquitous contaminant, and early-life exposure occurs in many species, including humans. While direct extrapolation requires caution, the study highlights the potential for early environmental insults to influence health across generations through metabolic reprogramming.

“This work emphasizes that pollution is not just an immediate problem,” Mo said. “Its legacy can extend far into the future, affecting organisms that were never directly exposed.”

The researchers say their results underscore the need to consider multigenerational effects when assessing environmental risks and regulating persistent pollutants. By revealing the metabolic mechanisms underlying inherited toxicity, the study provides a deeper understanding of how environmental contamination can shape ecosystem health over the long term.

The study was published in New Contaminants.

 

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Journal reference: Chen Y, Lin H, Wang J, Li F, Amouri REL, et al. 2026. Multigenerational developmental and skeletal toxicity from benzo[a]pyrene exposure in F0 and F2 medaka: metabolic trade-offs and survival costs. New Contaminants 2: e002 doi: 10.48130/newcontam-0025-0022   

https://www.maxapress.com/article/doi/10.48130/newcontam-0025-0022  

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About the Journal:

New Contaminants (e-ISSN 3069-7603) is an open-access journal focusing on research related to emerging pollutants and their remediation.

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