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EPA Proposal for Endocrine Disruption Testing of Pesticides Is Too Narrow in Scope
After failing to comply with the 1996 Congressional mandate to determine whether pesticides disrupt the endocrine system of humans and other organisms, the U.S. Environmental Protection Agency (EPA) is revisiting its approach to the implementation of the Endocrine Disruptor Screening Program (EDSP) with a new proposal that falls short of what is required to protect people and ecosystems. The proposal is open for public comment by February 26, 2024.
A detailed examination can be found in draft comments by Beyond Pesticides.
Because of its limited scope, the EPA's proposed framework for review of endocrine disrupting properties of pesticides is an abrogation of its responsibilities under the 1996 Food Quality Protection Act/Federal Food, Drug, and Cosmetic Act (FQPA/FFDCA) as well as the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and Safe Drinking Water Act (SDWA). The limitations in EPA's proposal, which do not comply with Congressional intent and statutory mandates, include: (i) applying EDSP to humans only; (ii) focusing on certain pesticide active ingredients only, and; (iii) restricting the types of data used to assess endocrine disruption (ED). The proposal reverses the advice of EPA's Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) and the agency's original EDSP implementation policy and science decisions.
Under FIFRA, a pesticide is presumed to pose an unreasonable risk until reliable data demonstrate otherwise. Moreover, if the agency lacks the data and/or resources to fully evaluate endocrine risks to human health and wildlife, then the agency is obliged to suspend or deny any pesticide registration until it has sufficient data to demonstrate that the pesticide's registration is in compliance with the statutory standard, which is no “unreasonable adverse risk” of endocrine disruption.
EPA cannot develop a strategy for evaluating pesticides without understanding the history and status of endocrine disruption research, which are summarized in Beyond Pesticides' draft comments. Evidence that synthetic chemicals can mimic or otherwise interfere with natural hormones has existed for over half a century. Although early attention was given to estrogen mimics, it soon became apparent that the homeostatic (stable) function of the endocrine system—which regulates and balances physiological functions—can be disrupted at many sites and hormone systems.
Endocrine disruption as a phenomenon affecting humans and other species has been critically reviewed by several authors. A common thread across these reviews is the notion that chemicals that may disrupt the endocrine systems of humans and wildlife may be pervasive in contaminating their habitats. A pandemic of endocrine-related disorders can be connected with endocrine-disrupting chemicals (EDCs), including attention deficit and hyperactivity disorder (ADHD), autism, diabetes, obesity, childhood cancers, testicular cancer in young men, infertility, male dysgenesis syndrome, hypospadias, low sperm count, loss of semen volume and sperm quality, and increased risk of testicular and prostate cancer. All these disorders have been increasing in incidence and can be traced back to prenatal exposure to EDCs.
Endocrine pathways are largely conserved (identical or similar) across species and, thus, are not species—or taxa—specific. It is well known that thyroid endocrinology in particular is well conserved across vertebrate taxa. This includes aspects of thyroid hormone synthesis, metabolism, and mechanisms of action. Thyroid hormones are derived from the thyroid gland through regulation of the hypothalamic-pituitary-thyroid (HPT) axis, which is controlled through a complex mechanism of positive and negative feedback regulation. Multiple pathways contribute to the synthesis of thyroid-releasing hormone, including thyroid hormone signaling through feedback mechanisms; leptin and melanocortin signaling; body temperature regulation; and cardiovascular physiology. Each pathway directly targets thyroid-releasing hormone neurons. Based on the similarities sensitivity and requirements of endocrine pathways across vertebrate species, it is well understood that the ecological assays (the frog assay in particular) are often more sensitive and equally relevant to mammalian assays in informing risk assessors of whether a chemical can perturb and cause adverse endocrine outcomes in the human population and vice versa.
FQPA essentially amends FIFRA to ensure potential endocrine-disrupting effects are considered in agency risk assessments to fulfill the FIFRA mandate that a pesticide registration will not cause unreasonable adverse effects. This applies to humans and wildlife and to all pesticide chemicals as defined in FIFRA, including “all active and pesticide inert ingredients of such pesticide” (21 U.S.C. 231(q)(1)). SDWA adds drinking water contaminants as well.
In summary, the agency cannot limit EDSP to only humans and conventional pesticide active ingredients without violating the statutory requirements enumerated in FIFRA, FQPA, and SDWA. EPA should make use of all available scientifically relevant endocrine disruption research findings and also be wary of deviating from established international efforts for screening/testing endocrine disruptors that incorporate human and wildlife relevant studies. Recognizing that mammalian data inform potential endocrine disruption in other vertebrate taxa (avian, amphibian, fish) and vice versa, the agency should not decouple the mammalian from other vertebrate assays in EDSP screening. There are more than 50 different ecological and mammalian assays included in the Organization of Economic Cooperation and Development (OECD) Conceptual Framework for screening/testing endocrine disrupting effects, and there are additional assays being developed for consideration as well. So, the agency should not limit the range or types of data to be used, but, as FQPA prescribes, use “appropriate validated test systems and other scientifically relevant information.” While currently required data may meet the needs of human risk assessment, it is inadequate to evaluate endocrine effects on wildlife species. It should also be understood that under FIFRA, a pesticide is presumed to pose an unreasonable risk until reliable data demonstrate otherwise. If the agency lacks the data and/or resources to fully evaluate endocrine risks to human health and wildlife, then the agency is obliged to suspend or deny any pesticide registration until the agency has sufficient data to demonstrate no unreasonable adverse endocrine risk per the mandate in FIFRA. Further, it is not the agency but pesticide registrants (manufacturers) that have the burden to demonstrate with adequate data that their products will not pose unreasonable adverse effects, including the inherently presumed endocrine-disrupting effects.
The target for this Action is the U.S. Environmental Protection Agency via Regulations.gov.
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Suggested comments to EPA:
EPA’s proposed endocrine disruptor strategy (EDSP) abrogates its responsibilities under the Food Quality Protection Act/Federal Food, Drug, and Cosmetic Act (FQPA/FFDCA), the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and Safe Drinking Water Act (SDWA). Limiting the scope of the EDSP to humans, certain pesticide active ingredients only, and limiting the types of data to assess endocrine disruption (ED) effects is contrary to the Congressional intent and requirements in these statutes. It is also a reversal of the Endocrine Disruptor Screening and Testing Advisory Committee advice and EPA’s original EDSP implementation policy and science decisions.
EPA’s strategy for evaluating pesticides requires understanding the history and status of endocrine disruption research. Evidence that synthetic chemicals can interfere with natural hormones has existed for over half a century. Although early attention was given to estrogen mimics, it was soon apparent that the homeostatic function of the endocrine system can be disrupted at many sites and hormone systems.
Many authors have documented that endocrine-disrupting chemicals (EDCs) may be pervasive in contaminating the ecosphere. A pandemic of endocrine-related disorders—attention deficit and hyperactivity disorder (ADHD), autism, diabetes, obesity, childhood cancers, testicular cancer in young men, infertility, male dysgenesis syndrome, hypospadias, low sperm count, loss of semen volume and sperm quality, and increased risk of testicular and prostate cancer—may be related to EDCs.
Endocrine pathways are largely conserved across species and thus are not species—or taxa—specific. Therefore, it is well understood that the ecological assays (the frog assay in particular) are often more sensitive and equally relevant to mammalian assays in determining whether a chemical can perturb and cause adverse endocrine outcomes in the human population and vice versa.
In summary, EPA cannot limit EDSP to only humans and conventional pesticide active ingredients without violating the statutory requirements of FIFRA, FQPA, and SDWA. EPA must use all available scientifically relevant endocrine disruption research findings and avoid deviating from established international efforts that incorporate human and wildlife studies. Recognizing that mammalian data inform potential endocrine disruption in other vertebrates (avian, amphibian, fish) and vice versa, the agency should not decouple the mammalian from other vertebrate assays in EDSP screening. With more than 50 different ecological and mammalian assays included in the Organization of Economic Cooperation and Development Conceptual Framework for screening/testing endocrine disrupting effects and additional assays in development, EPA must not limit the range or types of data to be used, but as FQPA prescribes, use “appropriate validated test systems and other scientifically relevant information.” Currently required data may meet the needs of human risk assessment but is inadequate to evaluate endocrine effects on wildlife species.
FQPA amends FIFRA to ensure potential endocrine-disrupting effects are considered in risk assessments to fulfill the FIFRA mandate that pesticide use will not cause unreasonable adverse effects. This applies to humans and wildlife and to all pesticide chemicals as defined in FIFRA, including all active and inert ingredients. Under FIFRA, a pesticide is presumed to pose an unreasonable risk until reliable data demonstrate otherwise. If EPA lacks the data and/or resources to fully evaluate endocrine risks to human health and wildlife, then the agency is obliged to suspend or deny any pesticide registration until the agency has sufficient data to demonstrate no unreasonable adverse endocrine risk.
Thank you.