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A study published in Environmental Science and Technology finds that there are 47 current-use pesticides — products with active ingredients that are currently registered with the U.S. Environmental Protection Agency (EPA) — detected in samples of indoor dust, drinking water and urine from households in Indiana.
This study builds on existing scientific literature documenting the public health threat of nonoccupational, indoor pesticide exposure. (See previous Daily News here, here and here.)
The study is a reminder that pesticides move into the indoor environment through the air and on clothing, making exposure more widespread than the assumptions used in regulatory reviews.
Background and methodology
“In this study, we collected matched samples of indoor dust, drinking water, and urine from 81 households in Indiana, United States, and analyzed these samples for 82 CUPs [current use pesticides], including 48 insecticides, 25 herbicides, and 9 fungicides,” said the authors.
They continue:
“Of these, 47 CUPs were identified across samples of indoor dust, drinking water, and urine with median total CUP (∑CUP) concentrations of 18 300 ng/g, 101 ng/L [nanograms per liter], and 2.93 ng/mL, respectively.”
The 13 herbicides detected include 2,4-D (2,4-dichlorophenoxyacetic acid), Alachlor, Atrazine, CIAT (Desethyl-atrazine), Diuron, Metolachlor, Metolachlor OA (Oxanilic acid), OIAT (2-Hydroxy-4-isopropylamino-6-amino-s-triazine), OIET (2-Hydroxyatrazine), Prometon, Simazine, Acetochlor and Acetochlor OA.
The 20 insecticides include neonicotinoids (Acetamiprid, Clothianidin, Dinotefuran, Imidacloprid, Thiacloprid, Thiamethoxam, NDMA [N-desmethyl-acetamiprid], and 6-CNA [6-Chloronicotinic acid]), organophosphates (Diazinon, Ethoprophos, Malathion, IMPY [2-isopropyl-4-methyl-6-hydroxypyrimidine], PNP [p-nitrophenol] and TCPγ [3,5,6-trichloro-2-pyridinol]), pyrethroids (3-PBA [3-Phenoxybenzoic acid], 4-F-3-BA [4-Fluoro-3-phenoxybenzoic acid] and Fenpropathrin) and phenylpyrazoles (Fipronil, Fipronil sulfone and Desulfinyl fipronil).
The nine fungicides detected include azoles (Myclobutanil, Propiconazole, Tebuconazole, and Metconazole), strobilurins (Azoxystrobin and Pyraclostrobin), amides (Boscalid and Metalaxyl) and the benzimidazole Carbendazim.
The participants were recruited through the Person-to-Person (P2P) Health Interview study cohort at Indiana University, which was approved by the university’s Institutional Review Board.
The dust, drinking water and urine samples were all collected on the same day for each study participant, with three samples per participant amounting to 243 total samples.
Samples were gathered between August and December 2020 and stored at negative 20 degrees Celsius before instrumental analysis. (For more information, see the “Instrumental Analysis” subsection on page “B.”)
The authors are researchers based at Emory University, as well as the Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks and the College of Chemistry and Environmental Engineering at Shenzhen University (China).
The authors declared that there is “no competing financial interest” in conducting this study.
In the acknowledgements, “[t]he authors thank Indiana University, the Indiana Clinical and Translational Sciences Institute, the Shenzhen Science and Technology Program (KQTD20240729102048052), the National Natural Science Foundation of China (22206071), the Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks (ZDSYS20220606100604008), and High Level of Special Funds (G03050K001) for funding this project.”
Results
“Our results show that indoor dust is a significant exposure pathway for most insecticides and fungicides, while herbicides are mainly consumed through drinking water,” said the authors.
“In addition, the toxicity equivalent factor model, incorporated with data retrieved from the ToxCast database, indicated that imidacloprid poses the greatest health risk based on its high exposure levels and toxicity.”
The authors also cite some additional findings of note below.
Thirty-seven CUPs were detected in indoor dust samples:
- Neonicotinoids and their “breakdown products” were the most abundant group of insecticides found in indoor dust, “contributing more than 70% to the total insecticide concentrations.”
- “Overall, the median total [neonicotinoid] concentration in indoor dust was 4,100 ng/g [nanograms], approximately 3 orders of magnitude higher than that reported in urban settings.
- “The most abundant herbicide detected in indoor dust was 2,4-dichorophenoxyacetic acid (2,4-D), which constituted more than 85% of the total herbicide concentrations.” Considering that 2,4-D has a short half-life of one and a half days, the authors believe that this “may indicate a recent application in the vicinity of the sampling area.”
- “Azole, strobilurin and amide fungicides were found in all indoor dust samples.”
Thirty-three CUPs were detected in drinking water samples:
- “[Organophosphates ] were more frequently detected compared to [neonicotinoids] and found at higher concentrations.”
- “Sixteen herbicides were found in drinking water samples. Herbicides were the predominant group of CUPs in drinking water samples and contributed 55% to the ∑CUP concentrations.”
- Atrazine and its breakdown products made up “over 50% of the total herbicide concentrations” accounted for in this study.
- Seven fungicides were detected in water samples, with Tebuconazole the only one to be detected in over half of the samples, while the other detected compounds were detected in less than 44% of the samples.
Nineteen CUPs were detected in urine samples:
- The most abundant concentrations of pesticides (in decreasing order) in urine came from insecticides, herbicides and fungicides.
- The top five highest concentrations of pesticides in urine samples included imidacloprid, dinotefuran, 2,4-D, Metolachlor OA, and 3-PBA.
- “Herbicides were detected in 93% of urine samples.”
- “Individual fungicides were detected in less than 50% of the samples.”
Additional noteworthy points raised by study authors include:
- Insecticides contributed 80% to average CUP concentrations in indoor dust, herbicides made up 55% (“the most abundant group”) of total samples for drinking water, and insecticides also made up the vast majority of concentrations in urine samples (82%).
- The average CUP concentrations in private water wells “were significantly lower” than municipal government-managed water sources, which “may be related to the local municipal water infrastructure.”
- “The EDIs [estimated daily intake] of individual CUPs were below the tolerable daily intake thresholds established by the U.S. EPA,” which is the risk assessment-based approach for calculating cumulative health risk, despite the peer-reviewed scientific literature.
Previous daily news
Other peer-reviewed studies document the presence of pesticide residues in indoor dust samples. A large European study of house dust contaminants, published in Science of the Total Environment, finds more than 1,200 anthropogenic compounds, including numerous organophosphates, the phthalate DEHP, PCBs, pharmaceuticals and personal care products, in indoor dust samples.
Additionally, an Argentine study centered around households with nonagricultural workers found that all dust samples contained mixtures, averaging 19 pesticides per sample and with a maximum of 32 per sample. Twelve pesticides were detected in more than 75% of the samples.
Imidacloprid, carbaryl, glyphosate and atrazine were detected in all samples. Seven of the 49 are used as both agricultural and veterinary or household pest compounds. (See Daily News here.)
The toxicity and pervasiveness of certain pesticides in this study, including the herbicide 2,4-D, have been documented in various reports and studies, as covered in previous Daily News.
A study published in Environmental Health Perspectives in 2024 was one of the first to indicate a link between exposure to the herbicides 2,4-D and glyphosate to the impairment of behavioral performance (i.e., attention/inhibitory control, memory/learning, language, visuospatial processing and social perception). (See Daily News here.)
2,4-D has also been found in all pregnant participants of a biomonitoring study published in Agrochemicals in 2024 in the Midwest region of the U.S. (Illinois, Indiana and Ohio).
“Cases were selected as participants in which any of the following occurred: hypertensive disorders of pregnancy, spontaneous preterm birth, gestational diabetes, stillbirth, or fetal demise < 20 weeks,” according to the researchers. (See Daily News here.)
Similarly, safe drinking water has been a key concern in terms of pesticide residues emerging in groundwater samples, water well samples and other areas that signal their pervasiveness and potential threat to human health.
Approximately 4 in 10 private wells in the state of Wisconsin contain toxic pesticides and pesticide metabolites, according to findings released earlier this year from a 2023 survey, entitled Wisconsin Agricultural Chemicals in Wisconsin Groundwater, conducted by the Wisconsin Department of Agriculture, Trade, and Consumer Protection in partnership with the U.S. Department of Agriculture’s National Agricultural Statistics Service. (See Daily News here.)
A report published by University of Connecticut researchers found that 46% of Connecticut waterway samples are contaminated with levels of the neonicotinoid insecticide, imidacloprid — one of the most widely used insecticides in the U.S. on lawn and golf courses. (See Daily News here.)
Studies on imidacloprid have linked the active ingredient to reproductive effects and a potential leacher, a possible contributor to various cancers, kidney/liver damage and a likely contributor to endocrine disruption and birth and developmental effects. Imidacloprid has been proven toxic to fish and aquatic organisms, as well as bees.
Call to action
Communities across the nation remain committed to moving beyond chemical dependence to address the issue of pesticide drift into our homes, where our loved ones may be inadvertently exposed to toxic pesticide residues that undermine immune systems and potentially contribute to deadly and chronic diseases.
You can take action today (see here) by telling the EPA to meet its obligations under federal pesticide and wildlife laws to facilitate a transition to organic practices.
Originally published by Beyond Pesticides.
