Increase in Agricultural Use of 2,4-Dichlorophenoxyacetic Acid

THURSDAY, Feb. 17, 2022 (HealthDay News) — Agricultural use of 2,4-dichlorophenoxyacetic acid (2,4-D) has increased since 2001, and is associated with high urine 2,4-D, according to a study published online Feb. 10 in Environmental Health.

Marlaina S. Freisthler, from the George Washington University in Washington, D.C., and colleagues used data from the U.S. National Health and Nutrition Examination Survey with available urine 2,4-D biomarker measurements from 2001 to 2014 to examine trends in urine concentrations. Urine values were dichotomized using the highest limit of detection (0.40 µg/L). By compiling publicly available federal and private pesticide application data, agricultural use of 2,4-D was estimated.

Data were included for 14,395 participants, of whom 32.5 percent had urine 2,4-D levels above the dichotomization threshold. The researchers observed a significant increase in the frequency of participants with high 2,4-D levels, from a low of 17.1 percent to a high of 39.6 percent in 2001-2002 and 2011-2012, respectively. The adjusted odds ratio was 2.268 for high urinary 2,4-D concentrations associated with 2,4-D agricultural use (per 10 million pounds applied). Compared with participants aged 20 to 59 years, children aged 6 to 11 years had 2.1 times higher odds of having high 2,4-D urinary concentrations. The odds were 1.85 times higher for women of childbearing age (20 to 44 years) than for men of the same age.

“Because herbicide use is rising, focused biomonitoring and epidemiological evaluation are needed to identify whether and how use and exposures are related to adverse health outcomes among vulnerable populations,” the authors write.

Two authors disclosed financial ties to the legal industry, including one who served as an expert witness in litigation involving herbicides.

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