Login
A study published in Environment International demonstrates the importance of shifting away from pesticides linked to health consequences not only for those spraying or working around pesticides, but also for residential communities exposed as a result of off-target exposure through drift.
The researchers find that elevated exposure to pyrethroid and organophosphate insecticides within 500 meters of residences is associated with gestational diabetes mellitus (GDM) risk, both in preconception and third trimester exposure windows.
According to the Centers for Disease Control and Prevention (CDC):
“Gestational diabetes happens when your body can’t make enough insulin during your pregnancy. Insulin is a hormone made by your pancreas. It acts like a key to let blood sugar into the cells in your body for use as energy.”
This research is only possible because Arizona is one of the few states in the U.S. to require commercial and agricultural pesticide applicators to report the quantity, type and location (within a one-square-mile system) of their spraying.
Public health and environmental advocates cite research like this when asking their elected officials to mandate permanent funding of federal programs that track pesticide residues across different exposure pathways, not to mention the need to advance organic land management in agricultural and non-agricultural contexts.
Methodology and main findings
Researchers at the University of Arizona and Harvard University used a robust dataset from the Arizona Prenatal Environment and Reproductive Outcomes Study, isolating eligible participant data to those with “singleton” (one child during delivery) births born between 2014 and 2020 to mothers who had no reported history of diabetes.
Pesticide use records on a one-square-mile basis were mapped using the U.S. Geological Survey’s Public Land Survey Section system, with researchers cross-referencing the reported “crop target” against the U.S. Department of Agriculture CropScape to attribute specific applications on delineated fields to assess those within 500 meters of the residence.
Eighteen active ingredients were analyzed across three core classes “based upon their most common commercial applications in Arizona, adequate number of exposed cases, and evidence from toxicological studies linking them to disruption of glucose metabolism.”
The authors continued, “We excluded from our analysis five active ingredients (i.e., diazinon, phorate, formetanate hydrochloride, oxamyl, and propamocarb hydrochloride) due to insufficient number of exposed cases (less than < 5).”
That being said, the pesticide compounds include:
- Organophosphates: Acephate, bensulide, chlorpyrifos, dimethoate, ethephon, malathion, tribufos
- Pyrethroids: Beta-cyfluthrin, bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, fenpropathrin, lambda-cyhalothrin, permethrin, zeta-cypermethrin
- Carbamates: Carbaryl and methomyl
Researchers assessed associations of pesticide exposure and gestational diabetes in four key windows — preconception (T0), first trimester (T1), second trimester (T2) and third trimester (T3).
The main findings include:
- Organophosphate exposure (acephate and ethephon) in the third trimester is associated with a 34% and 89% higher risk of GDM among exposed mothers [respectively].”
- Researchers “observed higher risk ratios that ranged from 1.17 to 2.13 for several pyrethroids” (beta-cyfluthrin, bifenthrin, cypermethrin, and permethrin) in preconception or first trimester.
- Chlorpyrifos exposure among pregnant individuals was associated with a “35% increased risk of GDM compared to their never-exposed counterparts.”
- While specific pesticide classes and active ingredients are correlated with increased GDM risk, overall pesticide exposure did not yield statistically significant results between the exposed (8.1%) and unexposed groups (7.8%).
Previous coverage
The pesticide exposure implications for residential exposure through multiple pathways (ingestion, dermal, etc.) cannot be understated given the preponderance of scientific evidence with adverse health effects (acute and chronic).
Researchers in the Czech Republic tested indoor dust across 116 homes and found that 93 percent of homes across urban and rural areas contained residue of at least one current-use pesticide (CUP).
The study also found residues of hexachlorobenzene and pentachlorobenzene, the breakdown products or byproducts of certain banned organochlorine pesticides.
These compounds, as well as DDT metabolites DDE and DDD, were detected in more than half of the homes tested.
Results in this study and previous research confirm that pesticides used outdoors find their way indoors, resulting in an exposure pattern that is not calculated when pesticides are registered and allowed on the market. The findings are published in Indoor Environments. (See Daily News here.)
In another noteworthy example, a California-based population study published in BMC Public Health finds that “7.5 [percent] of all pregnant people in California who gave birth in 2021 lived within 1 km [kilometer] of agricultural fields where OP pesticides [organophosphates] had been used during their pregnancy.”
Despite a 54% decrease in overall use of the neurotoxic insecticide chlorpyrifos in the state between 2016 and 2021, after a statewide ban on the organophosphate insecticide in 2016, researchers found that in one California county, “more than 50 [percent] of pregnant people lived within 1 km of OP pesticide use.”
Significant disparities were found in terms of elevated exposure to pesticides, “with Hispanic/Latine, young people, and residents of the predominantly fruit and vegetable growing Central Coast region being most likely to live near OP pesticide applications during pregnancy.”
The authors suggested that “regulatory changes to limit use or restrict applications in close proximity to residential areas could have a substantial public health benefit on children’s brain development.” (See Daily News here.)
A review of pesticide exposure of 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 and National Institute of Environmental Health Sciences 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.
This study, published in Environmental Advances, reexamines a quantitative analysis of 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. (See Daily News here.)
A review in the International Journal of Cancer links pesticide exposure, particularly in areas with high agricultural crop density, to increased risks for childhood cancers.
The team of researchers from the University of Nebraska-Lincoln and University of Nebraska Medical Center, in analyzing epidemiologic studies published between January 1980 and September 2022, says that “this scoping review affirms that a robust body of epidemiology literature already informs how parental and childhood exposure to environmental chemical exposures can be associated with children’s incidence of pediatric leukemia and brain cancer.”
“Given the short latency period (time between exposure and symptoms of disease) inherent in pediatric cancer, carcinogenesis may be uniquely linked to high-intensity environmental exposure and/or highly susceptible individual genotypes,” the authors noted.
They continued:
“Residential or agricultural pesticide use in spaces where children spend most of their time poses a significant risk to their well-being and physical development. Different types of pediatric cancers have varying latency periods, with bone cancers tending to occur in older children.
“In contrast, blood and brain cancers typically occur in children below the age of 10. Heredity is expected to play a role, but geographic disparities suggest that pediatric cancer may be affected by something other than inherited genetics, and something is disproportionately affecting the young population.” (See Daily News here.)
In that same vein, a new study is the first to assess the effect of pesticide exposures on the survival of children with leukemia.
The study found a statistically significant link between residential rodenticide exposure and a higher risk in children of death from acute lymphoblastic leukemia (ALL), with about 10% of the exposed children dying within five years of diagnosis.
Crucially, pre- and post-natal periods were the most critical exposure windows — and the intervals when residents were most likely to use rodenticides.
With proper treatment, about 80% of children diagnosed after age 1 with ALL can survive. (See Daily News here.)
Originally published by Beyond Pesticides.
