DINCH metabolites in urine samples of the German Environmental Specimen

Abstract

We analyzed 300 urine samples (24h voids) from the German Environmental Specimen Bank, for specific diisononylcyclohexane-1,2-dicarboxylate (DINCH) metabolites ranging from the simple monoester to several oxidized monoesters. Urine samples were collected in the years 1999, 2003, 2006, 2009 and 2012, 60 samples per year,from 30 male and 30 female volunteers (age: 21-29 years). The design of this retrospective study was chosen to investigate the time trend of DINCH exposure due tothe market introduction of DINCH in 2002 and increasing production volumes ever since (to approx. 200,000 metric tons in 2012). The samples were analyzed byon-line HPLC-MS/MS with isotope dilution quantification. The LOQs for the oxidized DINCH metabolites are 0.05 ìg/l and 0.1 ìg/l for the monoester. All samples wereblinded before analysis. We detected no DINCH metabolites in the 1999 and 2003 samples. From 2006 on the percentage of samples with DINCH metabolites above the LOQ increased significantly over the years (7% in 2006, 43% in 2009 and 98% in 2012). As expected, the hydroxyl monoester (OH-MINCH) was predominantfollowed by the carboxyl monoester (cx-MINCH) and the oxo monoester (oxo-MINCH). The median (and 95th percentile) of the OH-MINCH concentrations (in ìg/L) increased from 0.75, p>0.001). The median (95th percentile) DINCH intake in 2012 was calculated to be 0.14 (1.07) ìg/kg body weight/day. Our results impressivelyshow the advent and development of the exposure of the German population to DINCH since its market introduction in 2002. Daily intakes are still lower compared tothe phthalates it is used for as a substitute; future measurements will enable us to monitor the development of exposure. Quelle: Conference of ISEE, ISES and ISIAQ, Basel, Switzerland 19-23 August 2013