Department of Environmental and Occupational Health, Milken Institute School of Public Health, The George Washington University, 950 New Hampshire Ave NW Suite 400, Washington, DC, 20052, USA.
Heartland Health Research Alliance, Ltd., Brookfield, WI, USA.
Environ Health. 2022 Feb 10;21(1):23. doi: 10.1186/s12940-021-00815-x.
2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most extensively used herbicides in the United States. In 2012, 2,4-D was the most widely used herbicide in non-agricultural settings and the fifth most heavily applied pesticide in the US agricultural sector. The objective of this study was to examine trends in 2,4-D urinary biomarker concentrations to determine whether increases in 2,4-D application in agriculture are associated with increases in biomonitoring levels of urine 2,4-D.
Data from the National Health and Nutrition Examination Survey (NHANES) with available urine 2,4-D biomarker measurements from survey cycles between 2001 and 2014 were utilized. Urine 2,4-D values were dichotomized using the highest limit of detection (LOD) across all cycles (0.40 μg/L or 0.4 ppb). Agricultural use of 2,4-D was estimated by compiling publicly available federal and private pesticide application data. Logistic regression models adjusted for confounders were fitted to evaluate the association between agricultural use of 2,4-D and urine 2,4-D level above the dichotomization threshold.
Of the 14,395 participants included in the study, 4681 (32.5%) had urine 2,4-D levels above the dichotomization threshold. The frequency of participants with high 2,4-D levels increased significantly (p < .0001), from a low of 17.1% in 2001-2002 to a high of 39.6% in 2011-2012. The adjusted odds of high urinary 2,4-D concentrations associated with 2,4-D agricultural use (per ten million pounds applied) was 2.268 (95% CI: 1.709, 3.009). Children ages 6-11 years (n = 2288) had 2.1 times higher odds of having high 2,4-D urinary concentrations compared to participants aged 20-59 years. Women of childbearing age (age 20-44 years) (n = 2172) had 1.85 times higher odds than men of the same age.
Agricultural use of 2,4-D has increased substantially from a low point in 2002 and it is predicted to increase further in the coming decade. Because increasing use is likely to increase population level exposures, the associations seen here between 2,4-D crop application and biomonitoring levels require focused biomonitoring and epidemiological evaluation to determine the extent to which rising use and exposures cause adverse health outcomes among vulnerable populations (particularly children and women of childbearing age) and highly exposed individuals (farmers, other herbicide applicators, and their families).
2,4-二氯苯氧乙酸（2,4-D）是美国使用最广泛的除草剂之一。2012 年，2,4-D 是在非农业环境中使用最广泛的除草剂，也是美国农业部门第五大使用最广泛的农药。本研究的目的是检验 2,4-D 尿生物标志物浓度的趋势，以确定农业中 2,4-D 应用的增加是否与尿液 2,4-D 生物监测水平的增加有关。
利用 2001 年至 2014 年调查周期中具有可用尿液 2,4-D 生物标志物测量值的国家健康和营养检查调查（NHANES）的数据。使用所有周期中最高检测限（LOD）（0.40μg/L 或 0.4ppb）将尿液 2,4-D 值分为两类。通过编译公开的联邦和私人农药施用数据来估算 2,4-D 的农业使用情况。使用调整混杂因素的逻辑回归模型评估 2,4-D 农业使用与高于二分位数阈值的尿液 2,4-D 水平之间的关联。
在纳入研究的 14395 名参与者中，有 4681 名（32.5%）的尿液 2,4-D 水平高于二分位数阈值。尿液 2,4-D 水平高的参与者的频率显著增加（p<0.0001），从 2001-2002 年的最低点 17.1%增加到 2011-2012 年的最高点 39.6%。与 2,4-D 农业使用（每百万磅施用）相关的高尿液 2,4-D 浓度的调整后比值比为 2.268（95%CI：1.709，3.009）。6-11 岁儿童（n=2288）与 20-59 岁参与者相比，尿液 2,4-D 浓度高的可能性高 2.1 倍。生育年龄（20-44 岁）的妇女（n=2172）与同年龄的男性相比，高 2,4-D 尿液浓度的可能性高 1.85 倍。
2,4-D 的农业使用量从 2002 年的最低点大幅增加，预计未来十年还会进一步增加。由于使用量的增加可能会增加人群的暴露量，因此这里观察到的 2,4-D 作物施用与生物监测水平之间的关联需要进行重点生物监测和流行病学评估，以确定不断上升的使用和暴露量对脆弱人群（特别是儿童和生育年龄妇女）和高度暴露人群（农民、其他除草剂施药者及其家属）造成不良健康后果的程度。
