ABSTRACT
For decades, phthalates have been widely used as plasticizers in a large number of consumer products, leading to a complex exposure to humans via ingestion, inhalation or dermal uptake. Children may have a higher unintended dust intake per day compared to adults. Therefore, dust intake of children could pose a relevant exposure and subsequently a potential health risk. The aim of this study was to determine the relative bioavailability of certain phthalates, such as di(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP) and the non-phthalate plasticizer diisononyl 1,2-cyclohexanedicarboxylic acid (DINCH®, Hexamoll®), after ingestion of dust. Seven 5-week-old male piglets were fed five different dust samples collected from daycare centers. Overall, 0.43â¯g to 0.83â¯g of dust sieved to 63⯵m were administered orally. The piglets' urine was collected over a period of 38â¯h. The excreted metabolites were quantified using an LC-MS/MS method. The mean uptake rates of the applied doses for DEHP, DINP, and DINCH® were 43% ± 11%, 47% ± 26%, and 9% ± 3.5%, respectively. The metabolites of DEHP and DINP showed maximum concentrations in urine after three to five hours, whereas the metabolites of DINCH®, reached maximum concentrations 24â¯h post-dose. The oral bioavailability of the investigated plasticizers was higher compared to the bioaccessibility reported from in vitro digestion tests. Furthermore, the bioavailability of DEHP did not vary substantially between the dust samples, whereas a dose-dependent saturation process for DINP was observed. In addition to other intake pathways, dust could be a source of plasticizers in children using the recent intake rates for dust ingestion.
Subject(s)
Cyclohexanecarboxylic Acids/administration & dosage , Dicarboxylic Acids/administration & dosage , Dust , Phthalic Acids/administration & dosage , Plasticizers/administration & dosage , Administration, Oral , Age Factors , Animals , Animals, Newborn , Biological Availability , Chromatography, Liquid , Cyclohexanecarboxylic Acids/pharmacokinetics , Cyclohexanecarboxylic Acids/toxicity , Cyclohexanecarboxylic Acids/urine , Dicarboxylic Acids/pharmacokinetics , Dicarboxylic Acids/toxicity , Dicarboxylic Acids/urine , Male , Phthalic Acids/pharmacokinetics , Phthalic Acids/toxicity , Phthalic Acids/urine , Plasticizers/pharmacokinetics , Plasticizers/toxicity , Risk Assessment , Sus scrofa , Tandem Mass Spectrometry , Toxicokinetics , UrinalysisABSTRACT
Haem a and cytochrome c were isotopically labelled in mitochondria from rat heart and liver after injection of delta-amino[2,3-(3)H(2)]laevulate, a specific haem precursor. [guanido-(14)C]Arginine or l-[4,5-(3)H(2)]leucine were used to label mitochondrial proteins. Half-lives were measured from biological decay in vivo and were similar (5.5-6.2 days) for haem a, cytochrome c and [(14)C]arginine-labelled proteins. Labelling of hepatic mitochondrial proteins with [(3)H(2)]leucine resulted in a prolonged apparent half-life.
