21
Aug
Review of Pesticide Residues in Human Urine, Lower Concentrations with Organic Diet
(Beyond Pesticides, August 21, 2024) A literature review, published this month in the Journal of Agricultural and Food Chemistry, explores levels of pesticide residues found in samples of human urine with environmental exposure and dietary intake and confirms prior findings about the benefits of an organic diet. Similar to past findings, lower concentrations of chemicals are detected in the urine of participants who report eating an organic diet. By analyzing 72 scientific research studies published between 2001 to 2023, the review assesses routes of exposure and “explores urinary concentrations and detection frequency of metabolites of organophosphates and pyrethroids, as well as herbicides such as 2,4-D and glyphosate,†the authors say.
While “exposure to pesticide residues is influenced by a variety of demographic factors, including occupation, agricultural practices, seasonal variations, residence, diet, age, and gender,†the authors say, the concentrations of pesticides and their metabolites in human urine highlights the disproportionate risk to certain groups as well as the overall threat to the health of humans and the environment. Pesticide exposure can occur from dermal/skin contact or inhalation, through residence or work, and with dietary intake.
“Pesticides in urine can be detected as parent compounds, specific metabolites corresponding to a specific pesticide, and nonspecific metabolites corresponding to pesticides chemical class, e.g., organophosphates,†the authors state. They continue, “Nonspecific metabolites are often targeted, as the aim in some cases is not solely to check exposure to a single pesticide but rather a range of pesticides. Parent pesticides may not always be observed due to metabolization.†The research that the authors review use levels of pesticides or their metabolites as biomarkers detected in urine samples, as it is minimally invasive and easy to collect, to gauge human exposure. Other biomarkers have been utilized to detect pesticides in hair.
While this review covers studies as far back as 2001, the authors highlight that from “2020 onward, there has been a significant increase in research output, with a total of 38 research papers [out of the 72 analyzed] published during the period 2020−2023.†The studies that were reviewed originate mostly from the United States, Spain, China, Thailand, and various European countries. The majority of studies focused on 50−200 participants (22 studies) or 200−1000 participants (24 studies) and targeted a range of ages (children only, adults only, and both adults and children).
Analyzing the results of the 72 studies reveals that 3-Phenoxybenzoid acid (3-PBA) is the primary metabolite detected in urine samples, as it is included in 34% of the studies. 3-PBA is a nonspecific metabolite of pyrethroid insecticides like deltamethrin, cypermethrin, and permethrin. A specific metabolite for the pyrethroid cypermethrin, known as DCCA (cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid), was also commonly detected. Pyrethroids have been associated with cancer, endocrine disruption, reproductive effects, neurotoxicity, skin irritation, kidney and liver damage, and birth/developmental effects.
Diethyl phosphate and dimethyl phosphates, nonspecific metabolites of organophosphate insecticides, are detected in 32% of the studies. 3,5,6-Trichloro-2-pyridinol (TCPy), a specific metabolite of the organophosphate chlorpyrifos and chlorpyrifos-methyl, is included in 31% of the studies. Chlorpyrifos, and many other pesticides within the organophosphate class, are also linked to cancer, endocrine disruption, reproductive effects, neurotoxicity, skin irritation, kidney and liver damage, and birth/developmental effects. Studies highlight the impact of chlorpyrifos exposure to brain function damage, respiratory diseases and diabetes, and depression and suicide.
A study conducted in the Czech Republic finds that elevated levels of metabolites in urine, particularly DCCA and TCPy, have been linked to increased oxidative stress. The effect of pesticide residues on oxidative stress is also demonstrated by a study conducted in Thailand where organophosphate metabolites were proven to cause oxidative stress. Oxidative stress can play a role in many conditions like cancer, Alzheimer’s disease, and heart disease.
Glyphosate and its metabolite aminomethylphosphonic acid (AMPA), as well as 2,4-D, are additionally included in several studies. These chemicals are also well-documented for causing oxidative stress and cancer, as well as many other detrimental effects. Beyond Pesticides has reported on these health impacts extensively here and here.
Higher concentrations of metabolites, such as 2-Isopropyl-6-methyl-4-pyrimidol (IMPy), TCPy, and ethylene thiourea (ETU), “were significantly associated with a higher incidence of behavioral issues, such as social difficulties, thought-related problems, and rule-breaking symptoms,†the authors share. “These findings suggest a potential relationship between pesticide exposure and epigenetic changes, as well as behavioral and neurobiological impacts.†See more studies on these health effects here and here.
Much of the scientific research that is included “analyzed occupational exposure in farmworkers, farmworkers and their families, spray applicants, and florists’ exposure to pesticides,†the authors state, who are shown to be “vulnerable group[s] due to their direct contact and their routine respiratory exposure to pesticides.†While farmworkers generally have higher pesticide exposure, many of the studies within this literature review find that adopting organic farming practices can reduce the levels of pesticides detected in their urine. It should be noted that the requirement In the Food Quality Protection Act (amendments to the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and the Federal Food, Drug, and Cosmetic Act) does not require occupational exposure to be included in a cumulative risk analysis for exposure through food, air, water, and land. As a result, when calculating the effect(s) of exposures that have a common mechanism of toxicity, the body burden of overall exposure, including dietary exposure, is not calculated by the U.S. Environmental Protection Agency (EPA).
Organic agricultural practices and eating an organic diet reveals evidence of reduced concentrations of metabolites, notably with 3-PBA, in urine samples. In comparing conventional and organic diets, the authors find, “a noticeable decrease in concentration is observed for phenols and phosphonate herbicides, with a 41−100% decrease, pyrethroid metabolites (16−100%), organophosphate metabolites (41−75%), and quaternary ammonium growth regulators (74−93%).†They continue, saying, “Detection frequencies of pesticides/metabolites significantly dropped from 10−100% to 0−50% when switching to an organic diet.â€
The path forward to protect human health, for not only disproportionately affected groups like farmworkers and their families, is organic. Under the Organic Foods Production Act (OFPA), organic agriculture embodies an ecological approach to farming that does not rely on or permit toxic pesticides, chemical fertilizers, genetically modified organisms, antibiotics, sewage sludge, or irradiation. Beyond Pesticides supports organic agriculture because it implements good land stewardship and achieves reductions in hazardous chemical exposures.
Choose organic to protect health and the environment by buying organic products or growing your own organic food. Beyond Pesticides suggests a complete switch from chemical-intensive agriculture to regenerative organic agriculture to sustain human, animal, and environmental health. Become a member to add your voice to the movement and take action each week to be part of the organic solution.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Hakme, E., Poulsen, M. and Lassen, A. (2024) A Comprehensive Review on Pesticide Residues in Human Urine, Journal of Agricultural and Food Chemistry. Available at: https://pubs.acs.org/doi/abs/10.1021/acs.jafc.4c02705.
