Potential sources of phthalate exposure in a Vancouver, BC birth cohort at three months of age

Published: November 1st, 2009

Revised: October 27th, 2013

Abstract

Phthalates are ubiquitous contaminants in humans and are of concern due to reproductive and respiratory effects. Food is considered a major source of phthalates. However, by three months infants exhibit a range of phthalate levels, unlikely to be explained exclusively by breast milk or formula intake. This pilot study uses urinary biomarkers for five major phthalates in infants from Vancouver, BC, at three-months of age to evaluate exposure from baby products and home furnishings.

Methods: The cohort of 150 infants and their families was recruited as part of a pilot for the Canadian Healthy Infant Longitudinal Development cohort (CHILD). A home and phthalate intake assessment (questionnaire, visual inspection, floor dust sample), and urine sample was conducted at three months old. Urine was analyzed for the monoester metabolites of di(2-ethyhexyl) phthalate (DEHP), benzyl butyl phthalate (BBzP), di-n-butyl phthalate (DnBP), di-methyl and di-ethyl phthalate (DMP, DEP) using automated on-line solid phase extraction and separation with HPLC and isotope-dilution tandem mass spectrometry.

Results: The first 48 urine samples showed a range of exposure for the metabolites of DEHP, BBzP, DnBP, DMP and DEP. 3.6–5.9–fold differences were found in mean values of the interquartile range (25th-75th percentile). In preliminary analyses, use of a plastic pacifier, skin products, laminate or vinyl flooring, and presence of a household member working with hazardous materials was more common in the highest exposure quartile, except for mono- (2-ethyl-5-oxohexyl) phthalate one of three metabolites of DEHP. The type of diaper, diaper creams or use of diaper wipes, was not associated with the upper quartile of any phthalates. Phthalates levels in house dust are pending.

Conclusion: These preliminary results from a pilot study of the CHILD birth cohort suggest that phthalate exposures in these three-month-old infants are associated with behavioural and home indoor environmental characteristics.