Before Donald Trump was elected, the Environmental Protection Agency (EPA) seemed destined to ban the pesticide chlorpyrifos. Young children exposed to the chemical showed pronounced attention problems, attention deficit hyperactivity disorder, autism spectrum disorder (previously referred to as pervasive development disorder or PDD), psychomotor delay, and mental delay.
Results from numerous studies and petitioning from the Pesticide Action Network North America (PANNA), along with the Natural Resources Defense Council (NRDC), led the EPA to prioritize the review of chlorpyrifos. The increased attention within various stakeholder communities culminated in a 2016 EPA report⁽¹⁾, which reads as if a chlorpyrifos ban were imminent.
However, the fate of chlorpyrifos was changed when Trump appointed Scott Pruitt to head the EPA. More on his reputation as a climate change denier and connections to the oil and gas industry later.
Chlorpyrifos Defined, Some Compare to Sarin Gas
Chlorpyrifos is an organophosphate pesticide which acts in humans as an acetylcholinesterase and butyrylcholinesterase inhibitor. There are many infamous chemicals belonging to this class, including sarin (military nerve gas) and malathion (pesticide).
The enzyme acetylcholinesterase degrades the chemical messenger acetylcholine in nerve junctions. Organophosphates bind strongly to the serine residue of acetylcholinesterase, incapacitating it and leading to an acetylcholine buildup in the nerves. Increased acetylcholine levels can lead to overexcitation and paralysis.
Under pressure to address the science against chlorpyrifos from PANNA and NRDC, the EPA revisited its earlier 2006 evaluation of chlorpyrifos. That was followed by release of the Revised Human Health Risk Assessment for Registration Review in November, 2016.
Here is a quote from that EPA paper:
The EPA’s assessment is that the Columbia Center for Children’s Environmental Health study, with supporting results from .. 2 U.S. cohort studies and the seven additional epidemiological studies reviewed in 2015, provides sufficient evidence that there are neurodevelopmental effects occurring at chlorpyrifos exposure levels below that required for AChE inhibition.
Real Effects From Chlorpyrifos Exposure
The Columbia Studies (eight total) followed over 300 women from Manhattan Island through pregnancy and beyond. They first used gas chromatography⁽²⁾ to detect for exposure to 22 different pesticides.
The effects on mothers exposed to chlorpyrifos stood out the most. Researchers measured their children’s IQ scores and parameters at three years old.⁽³⁾
The results were remarkable and featured adverse effects in the double digits:
Attention Problems: 11.26
PDD (autism spectrum disorder): 5.39
Psychomotor Delay: 4.52
Mental Delay: 2.37
These odds ratios were achieved with chlorpyrifos exposure at lower amounts than the traditional cut-off used by the EPA for acceptable pesticide dose levels.
Another excerpt from EPA’s 2016 report:
Historically, the EPA has used AChE inhibition as the critical effect for deriving risk assessment .. for OP [organophosphate] pesticides, including chlorpyrifos. However, there is a breadth of information available on the potential adverse neurodevelopmental effects in infants and children as a result of prenatal exposure to chlorpyrifos.
With that, chlorpyrifos, the most commonly used pesticide in terms of total mass per annum, seemed to have been marked for obscurity.
All that changed with one political appointment.
Should Head of the Environmental Protection Agency Know Science?
In a party-line vote, Oklahoma Attorney General Scott Pruitt was confirmed by the U.S. Senate to be Environmental Protection Agency Administrator on February 17, 2017. This is notable for a few reasons.
Scott Pruitt is a lawyer by trade. He has a degree in political science and a Juris Doctor. Whereas the previous four heads of the EPA were scientists:
- Catherine McCabe, BA Environmental Science
- Gina McCarthy, MS Environmental Health
- Bob Perciasepe, BS Natural Resources
- Lisa Jackson, BS Chemical Engineering
Furthermore, Scott Pruitt has sued the EPA 13 times and has received $300,000 in campaign contributions from the oil and gas industry over the years. He is well-considered to be a climate change denier.⁽⁴⁾
Dow Chemical Convinces Trump EPA Chlorpyrifos Isn’t Unsafe At All
His appointment seems to have caused a sea change at the EPA.
In response to a petition by the aforementioned environmentalist groups to prohibit chlorpyrifos, the EPA released a new report⁽⁵⁾ dated March 29, 2017. It varied considerably in content and tone from their pre-Pruitt determination.
The agency revises upward their prior safety levels, based on a study conducted by chlorpyrifos’ own manufacturer.
In the 2006 organophosphate cumulative risk assessment (OP CRA), each OP was assigned a 1OX Food Quality Protection Act of 1996 (FQPA) safety factor unless chemical-specific AChE data on young animals were available to generate a data derived safety factor. To best match the relative potency factor (RPF)s and Patient Oriented Discharge Summary (PODs) based on repeated dosing, the Agency used repeated dosing data in juveniles for developing the FQPA safety factors. For chlorpyrifos, at the time of the 2006 OP CRA, the only such data available were from the Zheng et al. literature study.[…]
Dow AgroSciences submitted a comparative cholinesterase study (CCA) for chlorpyrifos. CCA studies are specially designed studies to compare the dose-response relationship in juvenile and adult rats. […] The CCA study for chlorpyrifos is considered by EPA to be high quality and well-designed. […] As such, petitioners’ claims regarding the CRA and FQPA safety factor is denied.
So in one year, a favorable toxicology study from Dow Chemical materializes and the newly-appointed EPA head – with no science background – saves chlorpyrifos.
How to Find Chlorpyrifos in Food, Critical Warning for Parents
In view of all the known data, it is recommended that pregnant and nursing mothers avoid chemically-grown food if they can.
To learn the Chlorpyrifos levels on common fruits, check the USDA’s pesticide data reports.⁽⁶⁾