Sumario: |
Background: Mancozeb and its main metabolite ethylene thiourea (ETU) may alter thyroid
function; thyroid hormones are essential for fetal brain development. In Costa Rica, mancozeb is
aerially sprayed at large-scale banana plantations on a weekly basis.
Objectives: Our goals were to evaluate urinary ETU concentrations in pregnant women living
near large-scale banana plantations, compare their estimated daily intake (EDI) with established
reference doses (RfDs), and identify factors that predict their urinary ETU concentrations.
Methods: We enrolled 451 pregnant women from Matina County, Costa Rica, which has
large-scale banana production. We visited 445 women up to three times during pregnancy to
obtain urine samples (n = 872) and information on factors that possibly influence exposure. We
determined urinary ETU concentrations using liquid chromatography mass spectrometry.
Results: Pregnant women’s median urinary ETU concentrations were more than five times higher
than those reported for other general populations. Seventy-two percent of the women had EDIs
above the RfD. Women who lived closest (1st quartile, < 48 m) to banana plantations on average
had a 45% (95% CI: 23, 72%) higher urinary ETU compared with women who lived farthest away
(4th quartile, ≥ 565 m). Compared with the other women, ETU was also higher in women who
washed agricultural work clothes on the day before sampling (11%; 95% CI: 4.9, 17%), women
who worked in agriculture during pregnancy (19%; 95% CI: 9.3, 29%), and immigrant women
(6.2%; 95% CI: 1.0, 13%).
Conclusions: The pregnant women’s urinary ETU concentrations are of concern, and the
principal source of exposure is likely to be aerial spraying of mancozeb. The factors predicting ETU
provide insight into possibilities for exposure reduction.
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