Opinion: Get high-risk pesticides out of our bodies
But this is not a new phenomenon. In the 1970s and 1980s researchers clearly established that feeding pigs and chickens low-levels of antibiotics to promote faster growth was creating new antibiotic-resistant bacteria. Despite significant investment of public research dollars over decades to highlight this problem, large-scale animal feeding operations did little to curtail antibiotic use. Today feedlots remain a primary source of newly resistant bacteria complicating treatment of human infections.
Science heals only when heeded. Many of the problems plaguing our food and agricultural system persist because politicians, regulators and business leaders routinely ignore, twist, and undermine science. Willful disregard of science is often good for business. Few examples show this as clearly as the Environmental Protection Agency's checkered history in protecting the public from adverse health and environmental impacts triggered by EPA-approved uses of pesticides.
Chlorpyrifos exposure warnings
Take for example the efforts by the EPA to curtail risks arising from exposures to chlorpyrifos.
But first, some background is helpful explaining the unique role this insecticide has played in stress-testing the EPA's pesticide regulatory process over the last 30 years.
In 1987 we helped start a National Academy of Sciences project that led to the release six years later, in 1993, of a seminal report, Pesticides in the Diets of Infants and Children. Charles Benbrook was the staff director of the unit of the NAS carrying out this EPA-funded study; Phil Landrigan was the chair of the NAS study committee.
The 1993 report and its recommendations were widely embraced by the industry, environmentalists and the scientific community. Three years later, in a rare, unanimous vote in both the House and Senate, Congress passed the Food Quality Protection Act (FQPA). This historic legislation moved most of the recommendations in the 1993 NAS report into federal law. It gave EPA the mandate and new tools needed—or so we hoped—to finally deal with pesticides capable of damaging children's brains and disrupting a child's normal development.
High-risk pesticides, altered brain development
In the NAS report, chlorpyrifos was the "poster child" of high-risk pesticides known to increase the risk of neurodevelopment harm. As the debate over our recommendations matured in Congress, the impact of the FQPA on chlorpyrifos was front and center. From FQPA passage in 1996 through the four-year process of developing the detailed science policies and risk assessment procedures needed to implement the new law's mandates, potential impacts on chlorpyrifos was always a focus and flash point.
In 2000 EPA announced a deal with Dow AgroSciences, the major manufacturer—and defender—of chlorpyrifos. Dow agreed to not contest EPA cancellation of nearly all home and residential uses, and the EPA agreed to preserve most of the agricultural uses of chlorpyrifos. As a result, the deal ended sometimes high exposures impacting relatively few pregnant women and children living in treated homes and apartments, but allowed widespread farm use to continue, along with routine, daily exposures to essentially all consumers via food and drinking water.
Controversy in the wake of this outcome intensified scientific focus on chlorpyrifos. In the next two decades hundreds more animal studies would confirm the link between low-level, prenatal exposures to chlorpyrifos and altered brain development in young animals. Dozens of papers traced the mechanisms of such disruption to their biochemical, neurophysiological and genetic roots in many different organisms, including people.
At risk: Children's brains, behavior
Controversy in the wake of this outcome intensified scientific focus on chlorpyrifos. In the next two decades hundreds more animal studies would confirm the link between low-level, prenatal exposures to chlorpyrifos and altered brain development in young animals. Dozens of papers traced the mechanisms of such disruption to their biochemical, neurophysiological and genetic roots in many different organisms, including people.
But the new science that most dramatically altered the EPA's assessment of chlorpyrifos neurodevelopmental risk came from three epidemiologic studies published by teams from the University of California-Berkeley, Columbia University and the Mount Sinai School of Medicine. Especially taken together—as EPA does in forming "weight of the evidence" science judgements—these studies provided compelling, consistent evidence that chlorpyrifos exposures during pregnancy disrupt brain and nervous system development.
The impacts can include lasting impairment of children's cognitive abilities, IQ and behavior. Such exposures can also lead to attention deficit/hyperactivity disorder and autism, and other developmental and chronic health problems. And paradoxically, scientists came to realize some adverse impacts can be brought about at low doses, but not at higher ones, an unexpected but surprisingly common feature of many chemicals known as endocrine disruptors.
New science was also prominently featured in litigation pursued by a coalition of environmental, farmworker and health organizations. It began in 2007, and its 14-year journey through the courts has culminated in a series of Ninth Circuit U.S. Court of Appeals rulings in favor of the coalition.
'Your science doesn't matter'
The most recent Ninth Circuit order gives the EPA two options. The agency must determine, and explain, the science justifying its decision—that current and retained chlorpyrifos tolerances are safe—as required by the FQPA. Or, the EPA must move ahead with the process required to revoke all tolerances supporting unsafe residues of chlorpyrifos in food and drinking water.
The first option boils down to the Biden EPA endorsing the Trump EPA rejection of the detailed chlorpyrifos human-health risk assessment completed by the agency in 2015. That EPA chlorpyrifos assessment is the culmination of arguably the most sophisticated risk assessment ever conducted on a pesticide anywhere in the world. It concluded that prenatal chlorpyrifos exposures were likely disrupting children's neurodevelopment at extraordinarily low levels of exposure -- more than 1,000-fold lower than the levels of chlorpyrifos exposure that the EPA previously thought were safe.
Upholding the Trump Administration's rejection of that health assessment will be a slap in the face of the dozens of EPA staff scientists who had contended with and responded to a near-endless flurry of Dow challenges, regurgitation of flawed industry studies and other well-financed diversionary tactics. This choice by EPA would also send a regrettable message to the hundreds of independent scientists and research institutions that stepped up and helped the EPA address the chlorpyrifos-science challenges standing in the way of completing the 2015 chlorpyrifos risk assessment.
A default to the Trump EPA position ignores nearly two decades of new science and sends a chilling message to the research community: "Your science doesn't matter."
Pesticide regulation: Systemic reform
The capacity of chlorpyrifos to dodge the consequences of new science is not an isolated incident in the world of pesticide regulation. This is why we joined seven other scientists in publishing a commentary exposing systemic problems with pesticide use, risk assessment, and regulation in the journal Environmental Health.
Better decisions depend on severing the roots of these problems.
The same patterns evident in the history of chlorpyrifos regulation are evident in the case of other pesticides. Routine registrant tactics include manipulation of study designs, questionable statistical analyses, and bogus explanations of why adverse impacts observed in animal studies are "not treatment related."
Four solutions for EPA reform
This is why our first recommendation in the commentary may be the most important—we call for a shift away from registrant-commissioned and -controlled studies to mostly independent science in fulfilling core EPA study requirements. Such EPA-funded studies can and should be paid for by the registration fees imposed by EPA when asked to register a new pesticide use, or reregister existing uses.
Second, we must redirect existing resources to more accurate and timely measurements of pesticide levels in people. Today, the EPA depends almost solely on expensive, indirect methods like testing for pesticides in food, water and air. Such levels are just one of several parameters driving pesticide exposures. Our recommended shift to heavier reliance on direct measures of pesticides in people is especially crucial when, like today, overall pesticide reliance is rising and big changes are occurring quickly in the mix of pesticides people are exposed to.
Third, pesticide regulators should place greater weight on new scientific tools that are rapidly uncovering the mechanisms through which pesticides can cause adverse human health and environmental outcomes. The deep-set EPA bias against reliance on new science must end.
Fourth, we see a pressing need for pesticide risk-assessment science to integrate scientific information and tools from multiple disciplines. Science is moving fast, but regulatory test requirements and EPA risk assessment methods are stuck with test protocols and data requirements that were not even cutting-edge in the 1980s.
Pesticides and inert ingredients
Our commentary focuses on one other consequential problem with pesticide regulation: In a rewrite of federal pesticide law in 1972, Congress classified the chemical details of pesticide formulas as "Confidential Business Information" not subject to public disclosure. In the 50 years since, farmers, doctors treating people exposed to pesticides and scientists not working for the EPA or a pesticide registrant have tried to understand and prevent harm, and treat poisoning victims, without knowing the chemicals to which people are exposed. This is like searching for a needle in a haystack with leather gloves on.
The "other ingredients" listed on pesticide labels are mixed into the products sold to farmers and other pest managers to enhance pesticide performance. These co-formulants promote ease of use and stability in various mixtures with other pesticides and fertilizers. But some "other ingredients" are toxic, and some are even more toxic than the active ingredients in formulated products. Yet the EPA conducts very little testing on these other ingredients, and almost none on the environmental fate, metabolism and toxicity of the formulated products as sold and applied.
This is why our commentary calls for a simple fix -- Congress needs to amend federal law to direct the EPA to accurately and fully disclose on pesticide labels and in chemical safety data sheets all the chemicals and their concentrations in the pesticides people apply and to which the public is exposed.
Pesticide use and exposures are already high, and are rising worldwide. Regulators need better data, new tools and more accurate risk assessments based on real-world conditions to reliably identify and avoid high-risk pesticide uses.
The pragmatic steps and policy changes in our commentary are necessary in building the capacity of the scientific community and regulators to mitigate high-risk pesticide uses harming people. The need is most pressing, as stated nearly 30-years ago in the 1993 NAS report, in preventing harm to pregnant women, infants and children, as well as those most heavily exposed because they apply pesticides or live near farm fields or other places that are heavily sprayed.
Views presented here do not necessarily represent those of Environmental Health News, The Daily Climate, or publisher, Environmental Health Sciences.
Top photo of salad greens courtesy of Louis Hansel - Restaurant Photographer via Unsplash
