26
Mar
Pesticide User’s “Take-Home,” Other Nonoccupational Residues Raise Household Exposure Alarm
(Beyond Pesticides, March 26, 2026) 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 current 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.
Building on a 2019 study, researchers consider data from additional studies published between 2019 and 2024, “providing support that all three pathways contribute to pesticide exposure.” More importantly, the updated estimates of nontarget exposure to chlorpyrifos and atrazine are overall strengthened by the incorporation of new data, highlighting the pervasive nature of pesticides in the environment.
The secondary “take-home” exposure pattern highlighted in this study is not typically addressed in policy governing pesticide registration and the underlying risk assessments conducted under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and Federal Food, Drug, and Cosmetic Act (FFDCA). While FFDCA, in setting tolerances or allowable residues in food, requires a cumulative risk assessment for dietary and nondietary exposure to pesticides that have a common mechanism of toxicity (e.g., nervous system effects initiated by the inhibition of the enzyme acetylcholinesterase), take-home exposure is not included in the exposure calculus.
Methodology and Results
The goal of the original study, according to the authors (which include one of the lead authors, Nicole Deziel, PhD, of Yale School of Public Health, across both studies), was to develop “a data-driven algorithm for AHS spouses to estimate nonoccupational, active ingredient-specific, cumulative exposure in units of intensity-weighted days from multiple pathways.” The researchers use the same search terms to identify relevant peer-reviewed literature and systematic reviews from March 2015 to December 2024 to expand their review. They evaluate pesticide exposure measurement data based on indoor dust samples across the three pathways.
The algorithm was designed to assess relative differences (RDs) in the ratios of pesticide concentrations across different exposure scenarios. For example, RDs for agricultural drift exposure assess the ratio of pesticide concentrations between homes with or without occupational exposure to a spouse or household member. For more details, please see the Methods section, including the subsection on “Exposure database” starting on the second page of the study. The authors adjusted the algorithm in six ways to strengthen the relative weight of multiple exposure pathways for non-occupational exposure:
- The relative weights of each pathway are redefined as incremental exposure above background levels of pollution, as this is more in alignment with the unfortunate reality that we live in a polluted world at its baseline;
- Exposure inside the home environment is considered as a factor across the three exposure pathways, adding a more realistic representation of relative exposure intensity;
- Exposure estimates are more accurate and specific now that the researchers use pesticide-specific median application days rather than generic numbers;
- The increase in background data from nine to nineteen studies led to changes in the relative weight of each pathway in terms of exposure;
- Information on known-use confirms specific uses of pesticides and assists in developing more accurate weights among exposure pathways; and
- Pathways equations for take-home and agricultural drift now include frequency of use and years of exposure, with residential pathway adjusted similarly in terms of baseline level of pollution and time weighting.
“In summary, our updated literature review and meta-analyses allowed us to refine the non-occupational pesticide algorithm based on additional findings from the past decade to better characterize relative exposure rankings of cumulative exposure for our study population,” the authors write in concluding the article. They continue: “The resulting metrics will help us advance our knowledge of the health risks, including female-specific cancer outcomes, that non-occupational pesticide exposures pose to AHS spouses.”
In terms of take-home exposure results from this study, researchers find that there are 3.7 x higher pesticide levels in exposed households compared to the 2.6 x higher levels initially determined in 2019. In other words, this pathway is the most substantial contributor to nonoccupational exposure across the three pathways when applying chlorpyrifos-specific data to the algorithm. For agricultural exposure results, RDs increased as the distance from the field to the household increased, with 4.2 x higher pesticide levels when a specific pesticide is confirmed. In other words, the further the distance from fields, the lower the pesticide levels. For residential use exposure results, specific pesticide use data contributes to increased levels by a factor of 3.1. However, residential use exposure is generally less than agricultural use exposure pathways, although the authors note that the effect size depends heavily on which pesticide is used. Please see Tables 2-4 for additional information on the relative differences in exposure pathways based on the results of this study.
Previous Coverage
There are significant additional studies relying on AHS data that continue to sound the alarm on the widespread adverse health outcomes faced by communities exposed to pesticides.
For example, research study results “show greater diabetes risk” from exposure to organochlorine, organophosphate, and carbamate insecticides, phenoxy and other herbicides, and the fumigant carbon tetrachloride/disulfide exposure. A study, published in Environment International, evaluates nearly 4,000 diabetes cases drawn from AHS follow-up surveys between 1999 and 2021. Researchers find evidence of an association between 18 pesticide active ingredients and diabetes. These include two phenoxy herbicides, 2,4,5-T and 2,4,5-TP, and seven organochlorine insecticides (DDT, aldrin, dieldrin, chlordane, heptachlor, toxaphene, and lindane). (See Daily News here.) A novel study, published in Arthritis & Rheumatology in 2025, is the largest investigation of rheumatoid arthritis (RA) in women to date, finding evidence of heightened risks when exposed to insecticides through AHS data collected from over 400 eligible women. “With nearly 10 additional years of follow-up and more than 3-times as many cases than previous AHS reports on RA in spouses, this study of incident RA provides robust evidence that some insecticides may increase RA risk among women,” the study authors say. (See Daily News here.)
- Exposure to weed killer glyphosate induces oxidative stress in the body, a key biomarker known to heighten an individual’s risk of cancer, according to research published in the Journal of the National Cancer Institute by a team of scientists from the National Institutes of Health. The findings, which track study participants’ past use of glyphosate and exposure levels through urine, are particularly concerning in light of recent data showing that four out of five (81.6%) U.S. residents have detectable levels of glyphosate in their bodies. To better understand the risk borne by farmers, applicators, and the general public, researchers studied a cohort of individuals enrolled in the Biomarkers of Exposure and Effect in Agriculture (BEEA) study, part of the long-running AHS, which tracks how agricultural, lifestyle, and genetic factors affect the health of farming communities. A total of 369 BEEA participants took part, and four subgroups were established, determined by their reported glyphosate use. (See Daily News here.) In 2019, a different team of U.S. scientists based at University of California, Berkeley, University of Washington, Seattle, and the Icahn School of Medicine at Mount Sinai, New York, published a meta-analysis of studies on glyphosate-based herbicides (GBH), concluding that the evidence “suggests a compelling link between exposures to GBH and increased risk of NHL [non-Hodgkin lymphoma],” corroborating findings by the International Agency for Research on Cancer (IARC). (See Daily News here and here.)
There are additional studies beyond AHS data that also raise concerns. Researchers at the University of Caxias do Sul (Brazil) identify 29 peer-reviewed scientific studies with statistically significant findings that tie pesticide use to cancer diagnoses. The literature review is published in Saúde Debate. This collection and analysis of clinical trials, as well as epidemiologic, case-control, and experimental studies—from the United States, Brazil, India, France, Egypt, Colombia, Ecuador, Mexico, Italy, and Spain—add to the hundreds of peer-reviewed independent analyses connecting synthetic chemical dependency in food production and land management with mounting public health concerns. (See Daily News here.) Use of the herbicide dicamba increases humans’ risk of various acute and chronic cancers, according to research published in the International Journal of Epidemiology by the National Institutes of Health (NIH) in 2020. (See Daily News here.)
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All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Environmental Advances
