Oral exposure to lead for Japanese children and pregnant women, estimated using duplicate food portions and house dust analyses

Abstract

Background: Lead is a toxic metal abundant in the environment. Consumption of food contaminated at low levels of lead, especially by small children and pregnant women, raises a health concern.

Methods: Duplicated food portions and drinking water were collected over 3 days from 88 children and 87 pregnant women in Shimotsuke, Tochigi, Japan. Participants were recruited in this study between January 2014 and October 2015. Dust was also collected from their homes. Lead concentrations were measured and consequent oral lead exposure levels were estimated for this population at high risk to environmental toxicants. Lead concentrations of peripheral and cord blood, taken from children and pregnant women, and were also analyzed.

Results: Lead concentrations in food, drinking water, and house dust were low in general. Oral lead exposure to lead was higher for children (Mean ± SEM; 5.21 ± 0.30 μg/kg BW/week) than in pregnant women (1.47 ± 0.13 μg/kg BW/week). Food and house dust were main sources of lead contamination, but the contribution of house dust widely varied. Means ± SEM of peripheral and cord blood lead concentrations were 0.69 ± 0.04 μg/dL and 0.54 ± 0.05 μg/dL, respectively for pregnant women and 1.30 ± 0.07 μg/dL (peripheral only) in children. We detect no correlation between smoking situations and blood lead concentration in pregnant women.

Conclusion: We conclude that oral lead exposure levels for Japanese children and pregnant women were generally low, with higher concentrations and exposure for children than for pregnant women. More efforts are necessary to clarify the sources of lead contamination and reduce lead exposure of the population at high risk even in Japan.

Keywords: Body burden analysis; Duplicate food portion; House dust; Lead exposure.

Fig. 1

Lead intake per body weight per week from food, drinking water, and house dust. Beeswarm plot of oral exposure of Pb adjusted to the body weight per week (μg/kg BW/week) from food samples (a), drinking water samples (b), house dust samples (c), and total lead exposure (d). Medians (longer horizontal bars in the middle) and 1st and 3rd quartiles (lower and higher horizontal bars, respectively) were indicated in the graphs. The p values were indicated in the graphs (WMW test)

Fig. 2

Lead concentration in blood of pregnant women, cord blood, and children. Lead concentration in peripheral blood of pregnant women and children and cord blood collected when the pregnant women’s delivery. Medians (longer horizontal lines) and 1st and 3rd quartiles (lower and higher horizontal lines, respectively) were indicated in the graph. Lead exposure of pregnant women and children were compared using with Steel-Dwass test. The p values were indicated in the graph

Fig. 3

Smoking experience and passive smoking. Comparison of Pb concentrations in blood of pregnant women (a, b), cord blood (c, d) between non-smokers and smoking experienced (a, c), or between non-smokers and passive smokers (b, d). There was no statistical significance in all comparisons (WMW test)