This study compared manganese in shed baby teeth, maternal, cord and child blood, maternal and child urine, and house dust for 75 mother-child pairs in the Salinas Valley, where manganese-containing fungicides are widely applied. Cord blood manganese was about twice maternal delivery blood. Prenatal tooth dentin manganese correlated with house dust manganese and was higher when a farm worker lived in the home, but did not correlate with blood or urine.
Key numbers
- Blood manganese, geometric mean (GSD): maternal at 26 weeks gestation 14.6 µg/L (1.5; median 14.8; n = 53); maternal at delivery 20.7 µg/L (1.4; n = 53); cord blood 39.9 µg/L (1.4; n = 59); child at 24 months 25.0 µg/L (1.5; n = 37) (Table 1, p. 14698).
- Urine manganese, geometric mean: maternal at 26 weeks 0.5 µg/L (n = 59); child at 24 months 0.8 µg/L (n = 39) (Table 1).
- Tooth dentin manganese to calcium ratio (area under curve × 10,000), geometric mean: prenatal 0.51, postnatal 0.16 (Table 1).
- House dust manganese: geometric mean 153 µg/g (range 37 to 414; n = 46); loading geometric mean 511 µg/m2 (range 6.2 to 18,400) (Table 1).
- With versus without a farm worker in the home: prenatal dentin 0.51 versus 0.39 (p < 0.05); maternal blood at 26 weeks 15.7 versus 11.9 µg/L (p < 0.1); child urine at 24 months 0.59 versus 0.22 µg/L (p < 0.1) (Table 3, p. 14698).
- Prenatal dentin correlated with house dust manganese concentration, rs = 0.44 (95% CI 0.13 to 0.67) (Table 4, p. 14699).
- Limits of detection: 0.003 µg/L in blood and 0.01 µg/L in urine (Methods, p. 14696).
Methods (brief)
Teeth were sectioned and analyzed by laser ablation ICP-MS against calcium, separating prenatal and postnatal dentin and enamel at the neonatal line. Blood and urine were analyzed by ICP-MS. House dust was collected at about 18 weeks gestation. Spearman correlations and comparisons by farm-work status were computed.
Evidence fitness
The paper supports reporting of perinatal manganese levels in several human matrices from an agricultural community and the use of tooth dentin as a marker of prenatal exposure. It does not separate dietary from environmental sources and does not assess health outcomes.
Limitations
The sample is small and from one community with heavy fungicide use. Several group comparisons reach only p < 0.1. Blood and urine manganese are short-term measures, and the study notes that urine is not the main excretion route.
Related evidence
Update history
No substantive edit history is available in this build. The full commit record is available in git.