Exposure to phthalates, bisphenol-a, parabens and organophosphates among mother-child pairs

Abstract

Introduction: Organophosphates, phthalates, parabens and bisphenol-a are chemicals with applications as pesticides, solvents and plasticizers. The long term exposure, even at low doses, has been connected with serious adverse health effects. Early-life exposure is considered as the most critical. Urinary metabolites of the above-mentioned chemicals are used as exposure biomarkers. Methods: Exposure levels were assessed in a mother-child cohort (Crete, Greece) during pregnancy (6th month) and at children (2.5 and 4 years of age) by determining six parabens, bisphenol-a, seven phthalate and six dialkylphosphate metabolites in their urine. Spot samples (N=978) were analyzed with liquid chromatography-tandem mass spectrometry. Phthalates were determined in drinking water and indoor air of houses and car interiors of the study area. Results: Principal component analysis grouped exposure in three main sources: plastic (all phthalates-BPA), personal care products (di-ethyl phthalate-parabens) and food (organophosphates). There were correlations for specific metabolite (2-tailed Spearman, p<0.001) between levels a) at pregnancy and at 2.5 year old children b) and children age/gender. Total daily intake was calculated; in general it was highest in mothers and lowest in 4 years old children. In some cases exceeded ESA and USEPA limits (e.g. 5% of all subjects exceeds USEPA-TDI for di-2ethylhexyl phthalate (DEHP)). Drinking water and indoor air contribution to the total phthalate daily intake was low. Relative rates of DEHP metabolism were calculated. Discussion: Pregnant women and children are exposed to mixtures of the above-mentioned chemicals. Some specific sources (three phthalates and ethyl paraben) are common during pregnancy and at 2.5 years old children. Although levels in our country in most of the studied chemicals are comparable with other studies, exposure is significant. Overall exposure and rate of DEHP metabolism are related with gender and age.