(Beyond Pesticides, July 24, 2017) A new report by the National Academies of Sciences, Engineering, and Medicine (NAS) is recommending to the U.S. Environmental Protection Agency (EPA) a strategy to evaluate the evidence of adverse human health effects from low doses of exposure to chemicals that can disrupt the endocrine system. NAS believes that EPA’s current process, which utilizes traditional toxicity testing, would miss some effects that occur at doses lower then what EPA evaluates. EPA’s Endocrine Disruption Screening Program (EDSP) is currently screening chemicals for their potential to interact with the endocrine system, but the program is years behind schedule and has been criticized for using outdated methods.
Endocrine disruptors are substances that can cause a variation in normal hormone function. Even small alterations in hormone concentrations, particularly during embryonic development and developmental phases of life, can have lasting and significant effects. Mounting science is showing that disruptions to the hormone system can occur at very low doses that according to NAS, are lower than those used in traditional toxicity testing by EPA. This means that some effects may be missed. EPA’s methodologies have been criticized over the years for failing to adequately capture impacts at low doses.
EPA requested NAS develop at strategy to evaluate evidence of low-dose effects. A systematic review of human and animal data on select chemicals was conducted by a committee of scientists and medical researchers to demonstrate how low dose results can be integrated and assessed. The resulting report proposes a strategy to evaluate evidence of adverse human health effects from endocrine disrupting chemicals at low doses that is arranged in three broad steps:
- Surveillance– Surveillance can detect signals of possible health effects by actively monitoring new data, scientific literature, nontraditional information sources, and stakeholder input to ensure health effects are being identified and analyzed on a regular basis.
- Investigation and Analysis– To further investigate the signals, the agency should analyze existing data, generate new data to fill gaps, conduct a systematic review of evidence, or integrate evidence from human and animal studies. One or more of these options might be needed to answer questions about potential signals.
- Action– Possible actions the agency could take include updating chemical assessments, regularly monitoring for new data, requiring new data or models to reduce uncertainties, or updating toxicity-testing designs and practices. Additional considerations, such as the public health significance and available resources, would also factor into the decision making
According to the report, EPA is already conducting many activities consistent with the strategy proposed, but its efforts may not be aimed specifically at evaluating low-dose toxicity testing. EPA had previously defended its testing procedures saying its current system is adequate for evaluating low dose effects, but that low dose effects were not common. NAS notes that the conclusions of previous toxicity assessments done by EPA may need to be updated to reflect the new results from the recommended strategy, as well as toxicity-testing practices that may need to be updated as new data are generated.
“The systematic review examples demonstrate how these approaches could be used in a strategy to evaluate low-dose toxicity of [endocrine disrupting chemcials] and also to identify lessons learned that could help EPA employ these methods successfully,” said David Dorman, PhD, professor of toxicology at North Carolina State University and chair of the committee.
As recommended in the proposed strategy, systematic reviews can be an important component in investigating evidence on low-dose adverse effects, and NAS notes EPA can build on existing systematic reviews that are published in peer-reviewed literature, and recommends performing meta-analyses of the animal and human evidence when appropriate. This allows data from several studies to be combined and used to evaluate confidence in the body of evidence, and to characterize the relationship between exposure and effect.
Endocrine disruptors can be found in common household products such as detergents, disinfectants, furniture, plastics, and pesticides, interfere with the body’s hormone system either by mimicking naturally produced hormones, blocking hormone receptors in cells, or effecting the transport, synthesis, metabolism or excretion of hormones. These impacts can result in devastating effects on one’s health, including behavioral and learning disorders, such as Attention Deficit Hyperactivity Disorder (ADHD), birth defects, obesity, early puberty, infertility, cardiovascular disease, and childhood and adult cancers. In 2013, the United Nations Environment Programme (UNEP) and the World Health Organization (WHO) declared Endocrine Disrupting Chemicals a global health threat. A 2016 report concluded that exposures to endocrine disrupting chemicals costs the U.S. more than $340 billion annually in health care costs and lost wages.
For more information on the effects of pesticides on human health, including endocrine disruption, see Beyond Pesticides’ Pesticide Induced Diseases Database.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: NAS News Release