Many things can impact the endocrine system—stress, food, exercise, pollution. ACC is engaged with the scientific community and regulatory agencies to enhance the scientific understanding of chemicals that may interact with the endocrine system and to promote sound decisions to effectively manage risks that may exist from exposure to them.
An endocrine disruptor is a substance that alters the function of the endocrine system and consequently causes adverse health effects in an intact organism. It is generally understood that the definition of endocrine disruption encompasses both the endocrine mechanism of action and adverse health effects. Natural variations in hormone levels and reversible or transient changes are commonly observed. However, since these changes are not considered adverse, they do not qualify as endocrine disruption.
In 1996, Congress directed the U.S. Environmental Protection Agency (EPA) to develop ways to measure the effects certain substances may have on the human endocrine system, including evaluating the risk they may pose and, if necessary, taking action to protect human health and the environment. EPA’s subsequent Endocrine Disruptor Screening Program (EDSP) has two tiers: screen substances for endocrine related activity, then determine if that activity can cause adverse effects at specific levels of exposure.
EPA recently formed an internal government work group to investigate the low dose hypothesis and non-monotonic dose response curves for endocrine disruptors. The Agency has published a dedicated web page for tracking the work group’s progress, including the development of a state of the science paper, which will be submitted for independent scientific peer review later this year.
ACC has encouraged EPA to use consistent and objective criteria for evaluating such studies, a transparent framework for evaluating the overall weight of the scientific evidence, and best practices for obtaining and responding to public review and comments. ACC continues to support EPA’s extensive research and development program to develop, standardize and validate methods to study substances and their potential effect on the endocrine system.
ACC’s Policy Position
Regulatory decisions about chemicals that may affect the endocrine system need to be based on several factors—whether a chemical causes endocrine-related activity, how this activity relates to realistic levels and means of exposure to the chemical, whether it produces adverse effects, and what steps may be needed to manage possible risks.
When screening substances for endocrine-related activities, especially when using emerging technologies, EPA must use validated methods so the results can be relied upon and trusted by all stakeholders.
An indication of endocrine-related activity must be viewed in the appropriate context—it should not be interpreted on its own as evidence of adverse effects.
When conducting safety assessments, EPA must use a “weight of evidence” approach, meaning the agency should consider all relevant safety data and not rely simply on one piece of information.
New methods and technologies for rapid screening of chemical substances are now emerging, such as EPA’s ToxCast program™ and EDSP21. ACC supports the evaluation, validation and implementation of such technologies that are relevant to endocrine effects.
EPA’s EDSP Tier 1 screening is an ambitious testing program that utilizes a suite of new, costly test methods. The Agency should continue to focus on completing EDSP List 1 screening, then evaluate the performance of each Tier 1 assays and the Tier 1 battery, and make adjustments as warranted, before moving on to EDSP List 2.
EPA must also communicate that the inclusion of a chemical or substance on either EDSP List 1 or List 2 in no way reflects a determination by EPA that the chemical is an endocrine disruptor.
EPA must be transparent regarding its plans for evaluating the low-dose hypothesis and non-monotonic dose responses. The Agency’s review and analysis should be firmly based on up-to-date scientific knowledge, meet the highest standards of scientific inquiry and be evaluated in accordance with acceptable scientific approaches.