Abstract

Overcoming challenges in measuring glyphosate exposure among pregnant women in rural Idaho

APHA 2022 Annual Meeting and Expo

Background: Like most contemporary pesticides, glyphosate is quickly metabolized with a biological half-life of ~15 hours. This rapid elimination, paired with potential for repeated but irregular exposures, suggests that within-individual excretion is likely highly variable. However, urinary biomonitoring studies often assess exposure using single spot samples, which may result in measurement error, misclassification and ultimately may obscure epidemiologic findings.
Objective: We aimed to characterize between- and within-individual variability in glyphosate exposure and to determine the number of spot samples required to provide a stable estimate of glyphosate exposure throughout pregnancy.
Methods: We recruited 40 women from southern and central Idaho during their first trimesters of pregnancy. Each participant provided weekly urine samples from enrollment until delivery. Samples were provided as the first morning void, and were analyzed for glyphosate concentration by the Centers for Disease Control and Prevention.
Results: We collected 864 weekly urine samples from 40 pregnant women between February 23 and December 20, 2021, representing an average of 22 samples per participant. Glyphosate was detected in 66% of the weekly samples, and the distribution of results was lognormal. The geometric mean glyphosate level in the entire dataset was 0.16 ug/L, with a standard deviation of 1.18 ug/L. Within- and between-individual variability will be presented, as well as the effects of season and residential location on participant exposure.
Conclusions: These data provide a roadmap for future researchers to determine the appropriate number of samples to collect to estimate long-term exposure to glyphosate and other pesticides with short biological half-lives.

Abstract

New insights from the Global Glyphosate Study on genotoxicity, reproductive outcomes and cancer

APHA 2022 Annual Meeting and Expo

Background
The Ramazzini Institute, together with an international group of independent Institutes and Universities, has launched in 2017 a pilot study and in 2019 started the most comprehensive, long-term integrated study ever on glyphosate-based herbicides (GBHs) – the world’s most heavily used weedkiller. The study has been named the Global Glyphosate Study. Results on the Pilot Phase of the Global Glyphosate Study showed adverse effects on reproduction-development, microbiome and genotoxicity at exposure levels that are currently considered safe and legally acceptable (US ADI 1.75mg/Kg/bw).
Objective
The aim of the integrated phase of the Global Glyphosate Study is to study the effects of GBHs on different outcomes on SD rats: genotoxicity, prenatal-developmental toxicity, neurotoxicity, multi-generational effects, endocrine disruption and microbiome effects, and long term-toxicity and carcinogenicity.
Methods
In the pilot study, pure glyphosate or Roundup Bioflow, were administered to SD rats in drinking water at 1.75 mg/kg bw/day to F0 dams starting from the gestational day (GD) 6 (in utero) up to postnatal day (PND) 120. In the long-term integrated study, animals were divided in ten study groups: control (drinking water), pure glyphosate (at 0.5, 5 and 50 mg/Kg/bw/day), Roundup Bioflow (0.5, 5 and 50 mg/Kg/bw/day glyphosate equivalent), and Ranger Pro (0.5, 5 and 50 mg/Kg/ bw/day glyphosate equivalent)
Results
The first results of the integrated study on microbiome, genotoxicity, reproduction, and pathology will be presented.
Conclusions
The long-term effects and the possible endocrine disruptive effects of GBHs are one of the main aspect of concern of the integrated study.

Abstract

Trends in exposure to 2,4-D and Glyphosate-based herbicides and associations with birth outcomes in a Midwest birth cohort

APHA 2022 Annual Meeting and Expo

Background: Preterm birth (PTB) affects 1 in 10 pregnancies overall and 1 in 7 pregnancies among Black pregnant persons in the US. Recent improvements in biomarker analysis have demonstrated near-ubiquitous global exposures to glyphosate and its persistent environmental degradate, AMPA, while exposure to other pesticides appears to be increasing as agricultural uses rise.
Methods: We evaluated exposure to glyphosate, glufosinate, AMPA, and MPPA and odds of spontaneous PTB (sPTB) in a nested case–control study within the Midwestern study sites of the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be (nuMoM2b) cohort study. Herbicide biomarkers were measured in stored first trimester urine samples. Associations were estimated between biomarker concentrations and sPTB using multivariable logistic regression.
Results: Out of 106 pregnancies (51 cases and 55 controls), there were glyphosate detections in 71.8%, AMPA detections in 79.3%, glufosinate detections in 0.0%, and MPPA detections in 12.3% of samples. Geometric means (95% CI) were 0.187 (0.154, 0.228) μg/L for glyphosate, 0.245 (0.204, 0.293) μg/L for AMPA, and 0.087 (0.077, 0.098) μg/L for MPPA. There was a statistically significant association between sPTB and hydration corrected AMPA biomarker concentration (Adjusted Odds Ratio 1.95, 95% CI 1.07, 3.56). The associations between sPTB and hydration-corrected glyphosate and MPPA concentrations were not statistically significant.
Conclusion: This study demonstrated a statistically significant association between sPTB and exposure to AMPA. This study contributes to the growing literature that exposure to glyphosate-based herbicides during pregnancy is associated with preterm birth.

Abstract

A Research Strategy for Tracking Herbicide Impacts on Children’s Health.

APHA 2022 Annual Meeting and Expo

Background. Children are increasingly exposed to herbicides through airborne exposure in agricultural communities, drinking herbicide-contaminated water, and consumption of herbicide-contaminated food, especially foods produced from genetically modified (GMO) crops, and grain and bean crops sprayed with herbicides late in the growing season to speed up harvest. Exposure can occur in utero through maternal exposure, and throughout infancy and childhood. Children are uniquely sensitive to herbicides and pound-per-pound of body weight have substantially greater exposures than adults. The health effects of early-life exposures are incompletely understood.
Objective. To outline a research strategy for assessing the short- and long-term impacts of early-life herbicide exposures.
Findings. Large, prospective birth cohort studies that enroll women during pregnancy, measure herbicide exposures during pregnancy and early childhood, and track children prospectively are essential for detecting adverse health effects of early-life herbicide exposures. Three key elements in such studies are accurate, individual-level exposure measures, especially during periods of heightened vulnerability; sensitive, validated techniques for detecting health outcomes; and long-term, multi-year follow-up of exposed populations. Collection and proper storage of biological and environmental samples collected in early life enables future application of new biomarkers. To maximize capacity for detecting health effects, data collection techniques need to be harmonized and standardized across multiple studies in different populations. Incorporation of genomic markers enables assessment of individual susceptibility. Clinical and toxicological findings can guide identification of health outcomes.
Conclusions. Prospective, multi-year epidemiologic studies are key to detecting adverse health effects of early-life herbicide exposures. However, efforts to protect children against hazardous herbicides through reduction in herbicide use cannot wait on epidemiologic data and must begin now.