Persistent environmental toxins accumulate in tissues already in the fetal stage
University of Oulu, Finland
Persistent organic pollutants (POPs) begin to accumulate in the tissues of mammals already during the foetal stage, according to new research from the University of Oulu, Finland. The animal-model study found that environmental toxins had built up in the tissues of sheep raised in clean organic production, and that the same substances were transferred in notable amounts to the developing foetuses’ adipose tissue.
Persistent environmental toxins, such as PCBs and DDT, remain in nature for long periods without breaking down. They can accumulate in the fatty tissues of organisms and bioaccumulate through the food chain. These substances were previously used in industry and as insecticides, and although their use is now strictly regulated, they remain widespread in the environment.
The study analysed tissue samples from 15 organic ewes and their lambs shortly after birth, searching for the most common POPs. Almost all of the substances investigated were detected in both adult sheep and lamb tissues. All the compounds identified were able to cross the placenta, and the transfer was so effective that concentrations in the lambs’ tissues averaged 30–103 per cent of those measured in the mothers.
Previous research in humans has shown that environmental toxins present in maternal circulation can pass through the placenta. What this study newly demonstrates is that, in sheep, compounds accumulated in the mother’s adipose tissue are transferred to the developing foetus in almost the same proportion.
Because placental structure in sheep differs from that in humans, no direct conclusions can be drawn regarding human exposure. However, concentrations of POPs in adult human adipose tissue are on average higher than in sheep, underscoring the need for further research.
‘The results illustrate the widespread distribution of persistent environmental toxins and the ways in which they infiltrate every part of our surroundings. In epidemiological studies, POP concentrations measured from umbilical cord blood after birth have been linked to obesity, metabolic syndrome and lower IQ. What remains for future research to determine is the extent of the health effects that POPs accumulated in adipose tissue may have on the foetus and on the child’s later health,’ summarises doctoral researcher Ella Vuoti.
Original article: Ella Vuoti, Jerry Nguyen, Panu Rantakokko, Heikki Huhta, Panu Kiviranta, Juha Räsänen, Sanna Palosaari, Petri Lehenkari. Adipose tissue deposition and placental transfer of persistent organic pollutants in ewes. Environmental Research, Volume 287, 2025.
Journal
Environmental Research
DOI
Enantioselective maternal transfer of pesticide metabolite and its thyroid effects
image:
HOW THE TWO MIRROR-IMAGE FORMS OF O,P'-DDD DIFFER IN THEIR TRANSFER TO OFFSPRING AND THEIR EFFECTS ON THE THYROID SYSTEM IN ZEBRAFISH.
view moreCredit: Lili Niu, et al
A new study published in Environmental Chemistry and Ecotoxicology has revealed that two mirror-image forms of a persistent pesticide metabolite behave differently when they move from mother fish to their offspring — demonstrating their environmental risks. Chiralmolecules that are mirror images of each other, like left and right hands.
“We were motivated by a simple question,” says lead author Lili Niu. “Many pesticides exist in two mirror-image forms, but environmental assessments usually treat them as if they're the same. We wanted to know whether that assumption is actually safe, especially across generations.”
To answer this, the researchers fed adult zebrafish diets containing each form of o,p'-DDD for four weeks. They then measured how much of the chemical accumulated in the adults and how much was passed to their developing embryos, as well as tracked hatching success, deformities, survival, and changes in thyroid hormones, which are essential for healthy growth.
“We found that offspring consistently carried even higher chemical levels than their parents, showing that maternal transfer was highly efficient,” shares Niu. “The S-enantiomer accumulated 134-176% more in adults and over 100% more in their larvae than its mirror-image R-form. This led to more severe outcomes in the next generation, including increased mortality, malformations, and reduced hatching success in the S-DDD exposed groups.”
To understand why, the team used computer-based modeling to simulate how each form of the chemical interacts with key proteins involved in producing and regulating thyroid hormones. “These simulations showed that S-DDD binds more strongly to several of these proteins, helping explain its greater biological impact,” says Niu. “What surprised us most was how consistently the S-form caused stronger effects at every level we tested.”
Notably, a small structural difference in the molecule led to very large differences in how much accumulated in the fish, how it affected their hormone system, and how their offspring developed.
The team emphasised that understanding enantiomer-specific effects will help improve ecological risk predictions for long-lasting pollutants and support the development of more accurate environmental standards.
“If we ignore these differences, we risk underestimating long-term harm to wildlife,” adds Niu. “Our work shows that even very low exposure in parents can create meaningful risks for the next generation.”
###
Contact the author: Lili Niu, Interdisciplinary Research Academy (IRA), College of Biological and Environmental Engineering, Zhejiang Shuren University, China, niulili@zjsru.edu.cn
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Journal
Environmental Chemistry and Ecotoxicology
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Enantioselective maternal transfer of chiral pesticide metabolite o,p’-DDD in zebrafish (Danio rerio): Implications for intergenerational thyroid disruption.
COI Statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
No comments:
Post a Comment