Lifestyle and Environment · Environmental Exposures
RRM Academy Synopsis
Urine data put 30% of 431 children over the cumulative phthalate limit
About 3 out of 10 Danish children exceeded the cumulative limit for three phthalates, a study of 431 children aged 3 to 6 found, based on urine samples. Dust from each child's home and daycare center allowed a second estimate. Indoor air and dust accounted for about half of children's total DiBP intake.
Key Findings
- Estimated from urine, total intake of di(n-butyl) phthalate (DnBP) exceeded the Tolerable Daily Intake in 22 of 431 children. Total intake of di(isobutyl) phthalate (DiBP) exceeded it in 23 children (5.3%).
- Summed intake of DnBP, DiBP and di(2-ethylhexyl) phthalate (DEHP), estimated from urine, exceeded the relative cumulative Tolerable Daily Intake (TDIcum) in 131 of 431 children (30%).
- Indoor pathways alone, averaged over a week, put DiBP intake above the Tolerable Daily Intake in 14 children (3.2%) and the three-phthalate sum above TDIcum in 26 (6%).
- Indoor air and dust accounted for approximately 100% of total diethyl phthalate (DEP) intake and 50% of DiBP intake, with dermal absorption from the gas-phase the major pathway.
- For butyl benzyl phthalate (BBzP) and DEHP, sources other than indoor air and dust supplied more than 90% of total intake.
Interpretation
The authors calculated intakes with models that rest on many assumptions about air concentrations, skin absorption, dust ingestion and time spent indoors. They suspect the indoor figure for DEP is overestimated. The authors note that the link between the two estimates may be influenced by the time that elapsed, up to a year, between dust collection and urine sampling. Urine came from a morning sample. DiBP has no established limit, so the DnBP limit was applied. The children came from an indoor environment and health study in Odense, Denmark, so the results describe 3- to 6-year-olds there. The study reports no health outcomes.
RRM Context
The authors cite indications that phthalates may affect semen quality and the onset of puberty in girls. They also cite one study that found an association with pregnancy loss. Restorative reproductive medicine looks for root causes in both partners. Chemicals that disrupt hormones are one place to look.
Abstract
Total daily intakes of diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(isobutyl) phthalate (DiBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) were calculated from phthalate metabolite levels measured in the urine of 431 Danish children between 3 and 6 years of age. For each child the intake attributable to exposures in the indoor environment via dust ingestion, inhalation and dermal absorption were estimated from the phthalate levels in the dust collected from the child's home and daycare center. Based on the urine samples, DEHP had the highest total daily intake (median: 4.42 µg/d/kg-bw) and BBzP the lowest (median: 0.49 µg/d/kg-bw). For DEP, DnBP and DiBP, exposures to air and dust in the indoor environment accounted for approximately 100%, 15% and 50% of the total intake, respectively, with dermal absorption from the gas-phase being the major exposure pathway. More than 90% of the total intake of BBzP and DEHP came from sources other than indoor air and dust. Daily intake of DnBP and DiBP from all exposure pathways, based on levels of metabolites in urine samples, exceeded the Tolerable Daily Intake (TDI) for 22 and 23 children, respectively. Indoor exposures resulted in an average daily DiBP intake that exceeded the TDI for 14 children. Using the concept of relative cumulative Tolerable Daily Intake (TDI(cum)), which is applicable for phthalates that have established TDIs based on the same health endpoint, we examined the cumulative total exposure to DnBP, DiBP and DEHP from all pathways; it exceeded the tolerable levels for 30% of the children. From the three indoor pathways alone, several children had a cumulative intake that exceeded TDI(cum). Exposures to phthalates present in the air and dust indoors meaningfully contribute to a child's total intake of certain phthalates. Such exposures, by themselves, may lead to intakes exceeding current limit values.