16
Jan
Multitude of Studies Find Epigenetic Effects from PFAS and Other Endocrine Disrupting Pesticides
(Beyond Pesticides, January 16, 2025) In Ecotoxicology and Environmental Safety, researchers highlight a multitude of studies on endocrine disrupting chemicals (EDCs) and endocrine disrupting pesticides (EDPs) showing epigenetic effects from exposure. These EDCs imitate the action of endocrine hormones and lead to gene damage and multigenerational adverse effects to health.
“These chemicals can interfere with the normal functioning of target tissues by altering their response to hormonal signals, thereby affecting various physiological processes including reproduction, development, the nervous system, the immune system, and even the process of carcinogenesis [causing cancer],†according to the authors from Hebei Agricultural University and Chinese Academy of Agricultural Sciences. Â
In causing epigenetic modifications, the authors describe that EDCs can create changes “at the nuclear and mitochondrial DNA (nDNA and mtDNA) or RNA levels, without changing the underlying DNA sequence. These alterations modify the structure or conformation of DNA, influencing gene expression and, consequently, cellular function.†They continue, “The mechanisms of epigenetics include changes in DNA methylation, chromatin modifications and the involvement of certain noncoding RNAs.â€
In reviewing over 80 studies on EDCs, predominantly fluorinated compounds such as per- and polyfluoroalkyl substances (PFAS), the researchers provide a summary of linkages between pesticide exposure and the threats to health on a cellular level. The studies on EDCs “include typical pesticides such as organophosphorus, organochlorine, pyrethroid, carbamate, and triazole pesticides, which can induce estrogenic, androgenic, and thyroid hormone effects in the body,†the authors note.
They continue: “Their actions hinge on intricate hormone signaling pathways, which have the potential to disrupt various aspects of the endocrine system in humans and other animals, leading to abnormal effects within the organism. It is widely recognized that the action of EDPs is related to their structural similarity to natural hormones, which endows EDPs with the ability to mimic endogenous hormones [those produced inside a cell] by binding to target hormone receptors.â€
With the high sensitivity of organisms to epigenetic changes, exposure to EDPs at very low concentrations poses a threat. These chemicals are also prone to accumulating in human tissues and can lead to chronic impacts. (See more on body burden here.) The authors describe exposure methods and the resulting implications in saying: “EDPs enter organisms through various routes, including food ingestion, breathing, and skin contact. EDPs exert endocrine-disrupting effects with potentially wide-ranging effects on the reproductive system. They can impact the development and functionality of the gonads, resulting in imbalances in sex hormone levels that may cause reproductive issues, including infertility and gonadal tumors.â€
There is a wide body of science showcasing the connection of pesticides to endocrine disruption. Numerous studies document exposure to EDPs, including PFAS, leading to dysfunction of the body’s endocrine system as well as additional health effects such as cancer, brain and nervous system disorders, immune system disorders, diabetes, learning/developmental impacts, and sexual and reproductive dysfunction.
Within the review, studies document:
- “[E]nvironmentally relevant concentrations of flutolanil [fungicide] resulted in a significant increase in the level of DNA methylation in the ovaries of zebrafish leading to an endocrine-disrupting response and detrimental effects on the development of their offspring.†Flutolanil also alters the expression of estrogen-responsive genes.
- Sulfoxaflor (insecticide) impacts bees by reducing survival and interfering with intestinal metabolites and steroid hormone biosynthesis.
- Epoxiconazole (fungicide) influences fetal and maternal steroid hormone levels, disrupts critical enzymes related to steroid hormone synthesis, and affects fetal development and endocrinological processes.
- Fipronil (insecticide) exhibits toxicities in both animals and humans including neurotoxicity, hepatotoxicity, nephrotoxicity, reproductive toxicity, and endocrine disruption.
- Trifluralin (herbicide) reduces fertilization in zebrafish with “sex-specific reproductive toxicity and endocrine-disrupting effects in these fish.â€
- Lambda-cyhalothrin (insecticide) reduces spermatozoa, leads to reproductive disorders in male mice, and “exhibits neurotoxic properties, disrupting the hippocampal neurodevelopment in mice via the estrogen membrane receptor signaling pathway.â€
- “[L]ow concentrations of endosulfan [insecticide] caused an estrogen-disrupting effect on MCF-7 [a human breast cancer cell line], and endosulfan significantly increased the expression of histone deacetylase (HDAC) and DNA methyltransferase (DNMT) in MCF-7, suggesting that endosulfan has a modulating effect on cellular epigenetic regulators.â€
- Embryonic stem cells from mice exposed to imidacloprid (insecticide), metolachlor (herbicide), and dichlorodiphenyltrichloroethane (DDT) (insecticide) experience induced cellular DNA methylation.
- Cyfluthrin (insecticide) impacts estrogen-responsive genes and progesterone receptor genes that lead to estrogen disrupting effects.
- Hexachlorobenzene (fungicide), methoxychlor (insecticide), and glyphosate (herbicide) are linked to molecular mechanisms that promote breast and ovarian cancer.
- EDPs are linked to disruptions in “various pathways involved in thyroid hormone biosynthesis, metabolism, receptor activation, and function†and lead to thyroid disorders.
In summarizing these results, the researchers state, “As a class of particularly representative endocrine-disrupting chemicals, the accumulation of per- and polyfluoroalkyl substances potentially leads to adverse health effects, including hormonal disruptions, developmental issues, and cancer.†These effects are as a result of complex mechanisms that are not yet fully understood or assessed in pesticide registration processes through the U.S. Environmental Protection Agency (EPA).
The researchers further explain: “Due to the distinct structural features of EDPs, the mode of their toxic action varies with different dosages, influencing the molecular mechanisms of hormone secretion, targets, and even the toxic pathways that affect various hormones in various ways indeed at extremely low concentrations. Nonetheless, the biological mechanisms underlying their effects remain incompletely understood. Consequently, the complexity of cell models is essential for summarizing and investigating the mechanisms of action of these EDPs.â€
Without fully understanding these mechanisms, advocates say, as previously reported by Beyond Pesticides, that EPA falls far short in addressing the full range of endocrine disrupting effects of all pesticide ingredients, as is required to protect human health and the environment. EPA should not approve or reregister pesticides until the full scope of the potential harm from chemicals can be addressed. (See additional Daily News coverage here and here.)
The authors reinforce this in saying: “A comprehensive evaluation of the toxicity of pesticides and their metabolites is necessary to understand their potential risks and take appropriate measures… Combined exposure to multiple EDPs has been indicated to have a synergistic effect, i.e., the effects generated by interactions of the EDPs are higher than the comprehensive effect caused by the individuals. It makes assessing and predicting the risk of EDPs more complex and critical.â€
To mitigate the endocrine disrupting effects of these pesticides that display detrimental long-term health effects, even at low doses, and threaten the health of humans and wildlife, the holistic solution of organic land management is available. In eliminating the use of petrochemical pesticides and synthetic fertilizers, organic methods safeguard public health and biodiversity.
To learn more about the benefits of organic land management, see here and here. Take action by helping to transition your community to organic through the Parks for a Sustainable Future program as a Parks Advocate. Become a member of Beyond Pesticides to add your voice to the organic solution and stay informed by signing up for our Action of the Week and Weekly News Updates.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Liu, Y. et al. (2025) The potential endocrine-disrupting of fluorinated pesticides and molecular mechanism of EDPs in cell models, Ecotoxicology and Environmental Safety. Available at: https://www.sciencedirect.com/science/article/pii/S0147651324016919.
