17
Apr
Research Identifies Pollution Effects on Organic Agriculture at Lower Levels
(Beyond Pesticides, April 17, 2026) A comparative analysis published in The Lancet Planetary Health highlights the pervasiveness of pesticide pollution in organic and non-organic farms in Latin America (Costa Rica) and Africa (Uganda). While pesticides were detected in nearly all participating farmers, there is a significant relationship between lower biomarker concentrations (often correlating with less contamination) in urine samples of organic farmers relative to non-organic farmers. The researchers also identified that older farmers held higher herbicide and insecticide concentrations.
This research builds on the preponderance of scientific evidence and lived experiences of agricultural communities across the globe, including the U.S., which documents nontarget contamination of food systems through air, water, and soil. In this context, Beyond Pesticides continues to advocate for a transition to organic land management practices.
Methodology and Results
“We collected urine samples from 601 conventional and organic smallholder farmers in Zarcero County, Costa Rica, and Wakiso District, Uganda, on two occasions during the primary spraying season,†the authors write in introducing their methodology. The researchers tested urine samples of small-scale farmers in Costa Rica and Uganda for a mix of pesticides that include a fungicide, herbicide and insecticides—mancozeb (ETU), 2,4-D, glyphosate, pyrethroid metabolites (3-PBA, DCCA), diazinon (IMPy), and chlorpyrifos (TCPy). Participant data were gathered across two visits, including height, weight, sociodemographic (age, sex, literacy, income), farm-related (drinking water source, farming practice, job role), and pesticide-related information (pesticide poisoning, pesticide training, glove use, and application of parent pesticides). For more details on the statistical analysis, please see page four of the study PDF.
The researchers received funding support from the Swiss National Science Foundation, Swedish Research Council, Swiss Network for International Studies, Universidad Nacional in Costa Rica, and State Secretariat for Education, Research and Innovation. This research is a continuation of the Pesticide Use in Tropical Settings (PESTROP) Study project, “an interdisciplinary and transdisciplinary research project studying environmental, health, and institutional dimensions of pesticide use in tropical settings.â€
In the introduction of their study, researchers point to existing data sets and evidence in Costa Rica (PESTROP study, see here and here) and Uganda (Improving exposure assessment methodologies for epidemiological studies on pesticides [IMPRESS] project), identifying pesticide safety training and organic farming as viable approaches to lower pesticide biomarkers in the human body. This study builds on the conclusions of previous research by comparing the relative reduction ranges of both approaches. “Lower biomarker concentrations were significantly associated with organic and mixed farming practices (24–68%) and with previous training on pesticide safety (17–27%),†according to the authors.
In other words, organic farming is more effective at reducing pesticide levels in the body relative to safety training that permits the continuous use of substances with known adverse effects.
The researchers conclude with some additional notable findings from the study:
- “In Costa Rica, 30 (11 percent) of 279 lived below the global poverty line, whereas in Uganda, 233 (78 percent) of 297 participants lived below the poverty line.â€
- “All seven biomarkers were detected in nearly all participants in both countries, confirming widespread pesticide exposure of smallholder farmers in tropical LMICs [lower- and middle-income countries].â€
- “Although Costa Rica had a higher number of applicators overall and more participants reporting pesticide application within the past week—suggesting a potentially higher application frequency—biomarker concentrations were not consistently elevated, probably due to lower pesticide quantities used per application, increased training, and greater PPE use.â€
- “Higher biomarker concentrations with increasing age could be due to slower metabolism and differences in fat distribution and body water compared with younger patients, as these factors alter the distribution and elimination of lipophilic compounds [defined as the ability ‘to dissolve, be disolved in, or absorb lipids (fats)’ according to the National Cancer Institute], such as pyrethroids.â€
- “An unexpected finding was the positive relationship between IMPy [diazinon] concentrations and glove use. During data collection, we observed that many farmers used gloves inconsistently and did not wash their gloves or hands after handling pesticides.â€
- “Given the consistent associations across countries, our findings are likely generalizable to similar populations; however, they might not be applicable in environmental or non-tropical settings with different exposure routes and pest pressures, and they should not be interpreted as representative of the entire countries, as our use of Costa Rica and Uganda refer only to the respective study areas.â€
- “There were approximately twice as many fungicide and herbicide applicators in Costa Rica as in Uganda, and a higher percentage of Costa Rican farmers reported applications within the last week, indicating a higher application frequency (Table 2). The percentage of insecticide applicators was similar in both countries; however, the percentage of applications within the last week appeared to be almost twice as high in Costa Rica as in Uganda.â€
Previous Coverage
The consequences of pesticide exposure cannot be understated, as evidenced by peer-reviewed scientific literature.
“The routine use of common pesticides in agriculture is no longer an ethically viable option for sustainable food production,†according to a new review in Reproduction & Fertility by livestock researcher Whitney Payne, Ph.D. candidate, and Kelsey R. Pool, PhD, of the School of Agriculture and Environment at The University of Western Australia. They base their position on the endocrine-disrupting qualities of many pesticides. (See Daily News here.)
Researchers at the U.S. Geological Survey (USGS) assessed pesticide and PFAS (per- and polyfluoroalkyl substances) contamination in ten agricultural streams in the San Joaquin and Sacramento Valleys (Central Valley) in 2024, detecting 60 pesticides, synergists, and associated transformation products, including 12 fluorinated pesticides (Dithiopyr, Trifluralin, Fluridone, Oxyfluorfen, Penoxsulam, Flubendiamide, Bifenthrin, Flonicam, Indoxacarb, Cyhalothrin, Fluopyram, and Penthiopyrad) that meet the Organisation for Economic Cooperation and Development (OECD) definition of qualifying as PFAS. “[T]he OECD fluorinated pesticides were generally detected more frequently and at higher concentrations†says the authors relative to the 48 other compounds. Relatedly, research finds products containing three of the detected pesticides (Methoxyfenozide, Imidacloprid, and Piperonyl Butoxide) associated with various PFAS, and according to the authors, there are a handful of active ingredients, such as the insecticide Methoxyfenozide and the fungicide Azoxystrobin, detected in 100 percent of collected samples. Their entire findings were published in Environmental Science & Technology Letters in March 2026. (See Daily News here.)
Adverse health effects of numerous pesticides have been identified in the literature. For example, in the International Journal of Molecular Sciences, a study of gestational (during pregnancy) exposure to the neonicotinoid insecticide thiacloprid shows epigenetic effects (alterations in genes without altering underlying DNA) within prostate tissues. To analyze the role of gene expression in subsequent generations after initial thiacloprid exposure, the authors exposed pregnant outbred Swiss mice to the insecticide in order to assess the offspring for multiple generations. As a result, the researchers from the Université de Rennes in France state, “Our study revealed that exposure to thiacloprid induces [cell] proliferation and is associated with epigenetic alterations in the sperm of genes important for prostate development.†Increased cell proliferation in the prostate can cause the development of conditions such as benign prostatic hyperplasia (BPH) and prostatic intraepithelial neoplasia (PIN), and lead to prostate cancer. (See Daily News here.) A literature review published in Chemico-Biological Interactions links pyrethroid insecticide exposure to cardiac dysfunction. Through a systematic review and meta-analysis of previous research through July 2025, the authors find emerging evidence that indicates pyrethroids induce adverse cardiovascular effects through pathways of inflammation, oxidative stress, and myocardial injury (damage to the heart muscle). (See Daily News here.)
In a study of birth outcomes in Arizona, published in the Journal of Exposure Science & Environmental Epidemiology, researchers find that preconception and prenatal exposure to certain carbamates, organophosphates, and pyrethroids increases the risk of lower Apgar scores, a metric used to assess neonatal health at one minute and ï¬ve minutes after birth. (See Daily News here.) A review of pesticide exposure from a family member working in agriculture (“take-home†residues) finds that pesticide levels in the home are elevated between 2.6- and 3.7-times. This and other nonoccupational exposure data from homes are drawn from the Agricultural Health Study (AHS), a National Cancer Institute (NCI) and National Institute of Environmental Health Sciences (NIEHS) prospective study of cancer and other health outcomes in a cohort of licensed pesticide applicators and their spouses from Iowa and North Carolina. Between 1993 and 1997, with follow-up between 1999 and 2021, AHS tracks occupational and nonoccupational exposure and subsequent health effects from pesticide exposure. The study, published in Environmental Advances, reexamines a quantitative analysis on nontarget, “active-ingredient-specific†exposure to pesticides from multiple pathways—applying new criteria to AHS spousal exposure to the insecticide chlorpyrifos and the herbicide atrazine. The three pesticide exposure pathways include take-home, agricultural drift, and residential use. (See Daily News here.)
Meanwhile, there is the continued emergence of evidence of organic agriculture’s benefits to public health, biodiversity, and climate resilience. Researchers in Germany and Brazil investigated the biodiversity of agricultural landscapes in “bee hotels†in organic and non-organic areas, finding a positive correlation between organically managed fields and numerous indicators of improved pollinator health, including an “increase in bee abundance, species richness, and diversity.†To analyze differing landscapes across eight conventional and nine organic nesting sites, the researchers identified ‘foraging zones’ around each site based on units of circular areas within a 500-meter radius. “Our study demonstrates positive effects of organic farming for solitary bees of the genera Heriades, Chelostoma, Hylaeus, Megachile, Osmia, Hoplites, and Coelioxys. Both brood cells and species abundance increased with a higher proportion of organic farming in the conventional agricultural landscape,†say the authors. (See Daily News here.) Another study published in Scientific Reports highlights the benefits of organic agriculture in comparison to different farming systems over five years on four crops (maize, tomato, faba bean, and potato). “Soil carbon sequestration is a long-time storage of carbon in soil which represents 70% of the carbon in land,†the authors note. “Therefore, the main aim of this study is to investigate the effect of the agricultural practice systems on the soil carbon sequestration and properties, productivity, water consumption, soil carbon sequestration, CO2 emission and cost of some agricultural crops.†As a result, the experiment reveals that, compared to chemical-intensive farming, organic methods enhance soil properties, reduce water consumption, provide higher yields and higher soil carbon sequestration, reduce CO2 emissions, and achieve the highest total net profit for all four crops after five years. (See Daily News here.) In a study published in Agriculture, Ecosystems & Environment, researchers from France find pesticide-free fields promote carabid beetles and spiders, generalist arthropod predators that consume slugs, aphids, and mites, that in turn support healthy, organic systems. (See Daily News here.)
Call to Action
You can sign up for Action of the Week and Weekly News Update to stay notified on ways you can take action to support public investments and programs that expand organic land management, in agricultural contexts and on public green spaces, parks, and playing fields, to ultimately move beyond a reliance on synthetic materials.
A recent action calls on Congress to reject the Farm Bill as passed out of the House Agriculture Committee and vote to extend the current law to protect health and the environment.
Additionally, as an individual, you can also sign a petition asking major food processors and mills to reject the use of genetically modified organism (GMO) wheat, which is grown with the highly toxic weed killer glufosinate. The petition, being distributed in collaboration with Friends of the Earth and a coalition of like-minded organizations, asks companies to reject the inclusion of glufosinate-tolerant HB4 wheat in the marketplace, transition away from GMO commodities, and shift to support organic agricultural products to protect farmers, farmworkers, consumers, and the environment.Â
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: The Lancet Planetary Health
