24
Sep
Human Health Disregarded with Obsolete Regulations and Risk Management, Researchers Find
(Beyond Pesticides, September 24, 2024) Recent commentary in Frontiers in Toxicology by two researchers, Maricel Maffini, PhD and Laura Vandenberg, PhD, highlights the pitfalls in the current regulatory systems in the United States (U.S.) for chemicals that threaten human health. Despite many advancements in science over the past few decades, and the wealth of studies that tie chemical exposure to negative health effects, risk assessments, and subsequent risk management, remain “static†and “outdated,†according to the authors.
“There is increasing concern amongst public health professionals, environmental health scientists, and medical organizations about exposures to synthetic chemicals,†the researchers say. “These organizations’ concerns are based on the overwhelming evidence showing associations between chemical exposures and adverse health outcomes in human populations.†Such concerns have sparked a debate on current regulatory methods for chemicals that are present in highly used products, such as pesticides, plastic containers, and food.  Â
The authors continue, “There are now thousands of studies showing associations between these chemicals and adverse health effects in humans including neurological disorders and learning disabilities, metabolic outcomes, infertility, thyroid dysfunction, and cancers.†Additional health effects can be seen in the Pesticide-Induced Diseases Database.
Of the many harmful chemicals, per- and polyfluoroalkyl substances (PFAS), and more specifically perfluorooctanoic acid (PFOA), have become increasingly scrutinized. Present in widely used products, these chemicals have high exposure, and “studies have revealed associations between PFOA exposures and human health effects including cardiometabolic issues, thyroid disorders, kidney and testicular cancer, and ulcerative colitis,†the authors point out. See more on PFAS here. With PFAS contamination in the spotlight, advocates are asking for protections from these compounds.
According to the researchers, some of the strongest evidence for the dangers that come with exposure to toxic chemicals is from persistent organic pollutants, such as PFAS, that bioaccumulate in animals, humans, and the environment and become biomagnified throughout the food chain. Bioaccumulation and biomagnification threaten entire ecosystems and biodiversity through cascading impacts.
The growing body of scientific evidence linking “chemical exposures to chronic diseases has led experts to deem the testing approaches recommended by regulatory agencies for risk assessment insufficient to protect human health,†the authors write. Current assessments do not utilize appropriate assays to assess endpoints such as developmental neurotoxicity, immunotoxicity, endocrine disruption, and non-genotoxic carcinogenicity, which leaves these serious impacts on human health unknown. The authors call for more sensitive and health-relevant endpoints to mitigate exposure to hazardous chemicals before they even enter the marketplace.
“Although the exact number of chemicals remains unknown, scientists estimate there are 140,000–300,000 chemicals on the global market,†the researchers report. The U.S. Environmental Protection Agency (EPA) alone has more than 42,000 chemicals listed on the Toxic Substances Control Act (TSCA) inventory that are available for use in consumer products or utilized in industrial processes. While pesticide product labels are required to list their active ingredients, there are many others (known as inert or other ingredients) that are not listed or tested in the same manner. This adds to the gaps in data for adverse effects of individual compounds as well as synergistic effects between compounds.Â
“Current approaches also rely on the assumption that testing chemicals one at a time is appropriate to understand how chemicals act under real-world conditions. Numerous mixture studies, including ones that demonstrated cumulative effects, have disproven this assumption,†the authors note. The synergy between substances within a single product or between multiple products used in tangent represents an area that can have exponentially worse impacts than the individual components alone, but synergistic effects are not considered during product registration. For example, a study “combining chemicals at concentrations that were 80-fold lower than their individual lowest-observed-adverse-effect-levels can act together to induce malformations of the male reproductive tract,†the researchers share. Additional studies on synergistic effects can be found here.
Proper pre-market testing needs to occur to protect the health of humans and the environment, but, as the authors state, “often the hazards of these chemicals are revealed years after they enter commerce, and in the U.S., there are very few options to restrict the use of chemicals once they have been allowed in products.†While suspensions and bans are within EPA’s power, they are not utilized often enough, safety advocates say. The “dacthal standard,†as Beyond Pesticides calls it, should be regularly implemented for handling the many chemicals that have been shown, through peer-reviewed scientific studies, to cause unnecessary risk to humans and other vital organisms.
Many of the current standard assays for risk assessment focus on acute toxicity in organisms such as fish, frogs, mice, or rats. These studies do not inform chronic effects that are increasing in human populations. There is also a need for more early-life exposure tests to “focus on health-related outcomes rather than overt signs of toxicity,†the researchers say. Previous early-life exposures from epidemiology studies include dichlorodiphenyltrichloroethane (DDT) being linked to later-life breast cancer risk, perchlorate and diminished IQ levels in children, and bisphenol A (BPA) and increased risk of asthma in children. See studies here, here, and here.
Risk assessments relying on outdated principles and expectations put human health at risk. “[C]ommon testing approaches assume that chemicals are quickly eliminated from the body, something that many PFAS and other persistent organic pollutants have disproven, even considering species-specific differences in their half-lives. In fact, this assumption continues to create problems in the testing (and risk management) of shorter-chain PFAS, which were assumed to be less bioaccumulative, and thus less hazardous, than the long-chain PFAS,†the authors relay. They continue, “Unfortunately, this was revealed to be untrue. Another long-held assumption is that chemical metabolites are less hazardous than the parent compounds. Phthalates, which have several metabolites that are more biologically active than the parent compounds, have disproven this assumption as well.†More extensive testing for all chemicals and their degradation products would create clarity for health effects and environmental fate.
The researchers highlight many areas that are currently lacking in the regulation of chemicals that humans are exposed to every day. Pesticide exposure can occur through inhalation, skin absorption, or ingestion from contaminated air, water, soil, or food. Even within the home, it is estimated that 75% of U.S. households used at least one pesticide product indoors in the past year. Other groups are at an increased disproportionate risk, such as people who live near agricultural fields and farmworkers/their children. According to previous EPA estimates, 13,000 to 15,000 farmworkers become ill from pesticide exposure each year, but that number could be as high as 300,000 if undiagnosed workers are included.
“Risk assessment involves the combination of hazard, exposure, and dose response data to quantify the probability of an adverse effect at a specific level of exposure. After a risk assessment is performed, the next step is to decide whether the risk to health is substantial enough that it must be managed,†the authors state. “Risk management is defined as ‘the process of weighing policy alternatives and selecting the most appropriate regulatory action, integrating the results of risk assessment with engineering data and with social, economic, and political concerns to reach a decision.’â€
With these established processes, advocates are enraged at the lack of emphasis on health and how slow federal and state agencies are to act in the face of protecting the public from these risks. “For example, repeated lawsuits against manufacturers of herbicides containing glyphosate have been successful because of strong evidence these products increase the risk of Non-Hodgkin Lymphoma, even though the EPA maintains that glyphosate does not cause cancer,†the researchers share. Despite these lawsuits and a wealth of scientific evidence, many products on the market still contain glyphosate.
As the authors say, “To address these problems collectively, we need reliable assays that can be used for risk assessment and regulatory purposes… [T]here needs to be evidence-based periodic post-market reevaluations and updated risk management decisions to remove the bad actors without introducing regrettable replacements.†This highlights the current pesticide treadmill in which any bans or restrictions result in the use of other harmful chemicals, that are often more toxic, as alternatives.
The researchers propose that risk assessments and regulations should rely on “modern scientific principles of toxicology including mixture toxicology, endocrinology, physiology, and immunology. Testing needs to be nimbler to account for the growth in knowledge of these fields over the last three decades and the new knowledge that is yet to come as well as the complexity of chemical exposures and new chemistries.†As science and our knowledge base evolve, so should the systems for assessments that are meant to inform decisions that have a wide impact on human and ecosystem health.
“[R]isk assessment informs risk management which may also consider the economic cost to the regulated industry, availability of safer substitutes, societal values, political will, and the precautionary principle. In an ideal world, risk assessment and risk management should be performed by different groups of experts to ensure that the risk assessment is solely based on scientific evidence and is not influenced by the ‘costs’ of taking action,†the authors postulate. This type of approach is in place in Europe regarding food and food packaging where the European Food Safety Authority and European Commission both play a role. The European Union (EU), however, still fails to accurately or reliably predict pesticide exposure rates, sometimes by several orders of magnitude, during the risk assessment process required for registration, as shown in a recent study covered by Beyond Pesticides.
“The problems we describe here illustrate a common paradox in U.S. regulatory agencies: they are mandated to make safety decisions based on science that is constantly evolving while the risk management is commonly static,†the authors conclude. “Better testing, and better use of testing data, can protect the public’s health.†Improvements in the risk assessments for chemicals within commonly used products will inform not only agencies like EPA but also consumers about the potential impacts that exposure to these compounds can have.
With more extensive testing, decisions regarding approving or reregistering products can be better informed and would result in less harmful products on the market. Any reforms to the current practices within EPA would face stiff resistance from the chemical industry and those aligned with their positions in Congress. The strategies currently in place in the U.S. and around the world leave all organisms, including humans, vulnerable to adverse health effects from chemical exposure and creates a pressing need for the public to call for change. By taking action, your voice can be heard on governmental actions that are harmful to health and the environment. You can also call for EPA action and promote safer options through strong organic values.
Organic alternatives to toxic chemicals found in pesticides would mitigate these harmful effects without the drawn-out process of reform. By promoting organic systems, the reliance on petrochemical pesticides and synthetic fertilizers is removed. This eliminates exposure to many products that can damage DNA, cause cancer, and even increase infant mortality.
Organic land management, whether in agriculture or on lawns/gardens, focuses on soil health and the health of all organisms within the ecosystem. By starting at the foundation, organic methods create a sustainable system in which all organisms that rely on each other are supported and biodiversity can flourish. This creates a healthy system with healthier food production without endangering the environment or any organisms within it.
Be part of the organic solution by becoming a member of Beyond Pesticides today. You can also participate as a Parks Advocate to transition your community towards organic land management, grow your own organic food, or support local organic farmers. Stay up to date on the latest science and policy with the Daily News and sign up for Action of the Week and Weekly News Updates to be delivered straight to your inbox to remain informed.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Maffini, M. and Vandenberg, L. (2024) Science evolves but outdated testing and static risk management in the US delay protection to human health, Frontiers. Available at: https://www.frontiersin.org/journals/toxicology/articles/10.3389/ftox.2024.1444024/full.
