Exposure to the plasticizer di(2-ethylhexyl) terephthalate (DEHTP) in Portuguese children – Urinary metabolite levels and estimated daily intakes

Classical ortho-phthalate plasticizers are, due to their endocrine disrupting potency and reproductive toxicity, increasingly replaced by alternative plasticizers. Di(2-ethylhexyl) terephthalate (DEHTP) is one of these substitutes. In this study, we investigated DEHTP exposure in 107 Portuguese children (4-17years old) by analyzing specific DEHTP metabolites in their urine using a newly developed LC-MS/MS method. We could detect the major, specific DEHTP metabolite mono(2-ethyl-5-carboxypentyl) terephthalate (5cx-MEPTP) in 100% of the samples with levels above the limit of quantification in 96% of the samples (median concentration 4.19μg/L; 95th percentile 26.4μg/L; maximum 3400μg/L). Other minor DEHTP metabolites (5OH-MEHTP, 5oxo-MEHTP and 2cx-MMHTP) were detected at lower rates and levels. Daily DEHTP intakes calculated from urinary 5cx-MEPTP levels were generally far below the tolerable daily intake (TDI) of 1000μg/kgbw/d (median 0.67μg/kgbw/d; 95th percentile 6.25μg/kgbw/d; maximum 690μg/kgbw/d). However, for one child the biomarker-derived health-based guidance value (HBM-I value) for 5cx-MEPTP of 1800μg/L was exceeded by about a factor of two. Levels of 5cx-MEPTP and calculated daily DEHTP intakes were higher in normal/under-weight children who nourished on their usual diet compared to overweight/obese children who received nutritional guidance with fresh and unprocessed food (p=0.043 and p<0.001 respectively). This indicates to processed and fatty foodstuff as a major source of DEHTP exposure. Additionally, we found children of lower age having higher DEHTP intakes (p=0.045). Again, foodstuff as a major DEHTP source, together with other child specific DEHTP sources such as mouthing of toys or ingestion of dust might be contributing factors. With the present study, we provide a first data set on the omnipresent DEHTP exposure in children. So far, general levels of DEHTP exposure seem no cause for concern. However, due to the increasing use of DEHTP as an ortho-phthalate substitute, possible increasing exposures in the future should be followed closely.info:eu-repo/semantics/publishedVersio

Contact allergy to thiurams: multifactorial analysis of clinical surveillance data collected by the IVDK network

To analyse the association between occupation (represented by job title) and contact allergy to thiuram vulcanising agents based on data of a clinical registry (IVDK, www.ivdk.org). Clinical, demographic and allergy patch test data of all patients tested between 1992 and 2006 with the thiuram mix (1% in petrolatum) as part of the baseline series was analysed (n = 121,051). Poisson regression analysis was used to quantify the association between different occupations (and other relevant factors) and a positive patch test reaction to the thiuram mix. Furthermore, the time trend of sensitisation prevalence was analysed in high-risk occupational subgroups identified. In comparison to a largely unexposed reference group (office workers and teachers), rubber manufacturers had a significantly elevated risk (prevalence ratio (PR): 5.1, 95% confidence interval (CI) 2.0-10.5). However, health care workers such as physicians and dentists (PR: 3.8, 95% CI: 3.0-4.8) or nursing staff (PR: 3.0, 95% CI: 2.5-3.6) as well as meat and fish processors (PR 3.5, 95% CI: 2.2-5.3) and cleaners (PR 3.1, 95% CI: 2.5-3.8) were found to have a high sensitisation risk as well. In case of health care workers, a significant downward trend during the study period was observed; while in food processors and cleaners, sensitisation prevalence remained largely stable. The adjusted multifactorial analysis identified occupations yet unknown to be associated with elevated thiuram contact allergy risk, e.g., food processors and cleaners. Thus, (i) further in-depth research can be targeted and (ii) efforts to prevent sensitisation to thiurams focussed, e.g., by limiting thiuram concentrations in products to a residual level which is technically inevitable