Polychlorinated dioxins, furans, and biphenyls in blood of children and adults living in a dioxin-contaminated area in Tokyo

Abstract

The soil of a residential area in Tokyo was found to contain dioxins, namely polychlorinated dioxins, furans, and dioxin-like biphenyls, the levels of which exceeded the environmental guideline [1,000 pg toxic equivalent (TEQ)/g] by up to 6.8 times. To assess the exposure levels of people living in this area and to study the possible relationship of blood dioxin concentrations of children with breast milk and/or formula feeding, a health survey was carried out in 2006, involving a total of 138 people, including 66 children aged 3-15 years, and blood dioxin concentrations and the characteristics and lifestyles of these people were analyzed. Mean ± standard error of the mean (SEM) of blood dioxin concentrations (pg/g-lipid) of group 1 (3-6 years old), group 2 (7-15 years old), and group 3 (≥16 years old) were 13 ± 1.9, 6.6 ± 0.65, and 10 ± 0.54, respectively. The congener/isomer profile of dioxins in blood samples differed markedly from that of the contaminated soil samples. According to the feeding mode of children, blood dioxin concentrations (pg/g-lipid) were 17 ± 2.9 for breast milk only, 7.4 ± 0.82 for both breast milk and formula, and 4.7 ± 1.1 for formula only, with a significant difference from one another. We conclude that people living in the dioxin-contaminated area are less likely to be exposed to excessive amounts of dioxins, and that blood dioxin concentrations of children aged 3-15 years seem to be strongly affected by breast feeding duration.

Fig. 1

Relationship of blood dioxin concentrations (pg TEQ/g-lipid) with age in the present study (n = 138, open circle), the 2004 Ministry of the Environment survey (n = 264, closed circle), and the 2004 Hachioji City study (n = 12, gray circle)

Fig. 2

Comparison of dioxin profiles (congener and isomer compositions) in blood samples of subjects (n = 248) and those in a representative most highly contaminated soil sample (0–5 cm from the surface) of a nursery ground in a dioxin-contaminated area of Kita City, Tokyo: congener compositions (a, d), isomers of PCDDs and PCDFs (b, e), and isomers of coplanar PCBs (c, f). Amounts of congeners and isomers are shown on a mass basis (a–c) and on a TEQ basis (d–f)

Fig. 3

Relationship of nursing period and blood dioxin concentrations: PCDDs + PCDFs (a), CoPCBs (b), and PCDDs + PCDFs + CoPCBs (c) on a TEQ basis. Breast (closed circle), mixed (breast and formula, gray circle), and formula (open circle) feedings are shown. The line and equation indicate an approximate estimate based on breast feeding

Fig. 4

Relationship of time after weaning to blood dioxin concentrations: PCDDs + PCDFs (a, d), CoPCBs (b, e), and PCDDs + PCDFs + CoPCBs (c, f) on a TEQ basis. Breast (closed circle), mixed (breast and formula, gray circle), and formula (open circle) feedings are shown. The line and equation indicate an approximate estimate based on breast feeding. Data are expressed on regular (a–c) and log (d–f) scales